drivers/gpu/drm/display/drm_dp_mst_topology.c

   1 /*
   2  * Copyright © 2014 Red Hat
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/bitfield.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/kernel.h>
  29 #include <linux/random.h>
  30 #include <linux/sched.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/iopoll.h>
  33
  34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35 #include <linux/stacktrace.h>
  36 #include <linux/sort.h>
  37 #include <linux/timekeeping.h>
  38 #include <linux/math64.h>
  39 #endif
  40
  41 #include <drm/display/drm_dp_mst_helper.h>
  42 #include <drm/drm_atomic.h>
  43 #include <drm/drm_atomic_helper.h>
  44 #include <drm/drm_drv.h>
  45 #include <drm/drm_edid.h>
  46 #include <drm/drm_print.h>
  47 #include <drm/drm_probe_helper.h>
  48
  49 #include "drm_dp_helper_internal.h"
  50 #include "drm_dp_mst_topology_internal.h"
  51
  52 /**
  53  * DOC: dp mst helper
  54  *
  55  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  56  * protocol. The helpers contain a topology manager and bandwidth manager.
  57  * The helpers encapsulate the sending and received of sideband msgs.
  58  */
  59 struct drm_dp_pending_up_req {
  60         struct drm_dp_sideband_msg_hdr hdr;
  61         struct drm_dp_sideband_msg_req_body msg;
  62         struct list_head next;
  63 };
  64
  65 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  66                                   char *buf);
  67
  68 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  69
  70 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  71                                      int id,
  72                                      struct drm_dp_payload *payload);
  73
  74 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  75                                  struct drm_dp_mst_port *port,
  76                                  int offset, int size, u8 *bytes);
  77 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  78                                   struct drm_dp_mst_port *port,
  79                                   int offset, int size, u8 *bytes);
  80
  81 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  82                                     struct drm_dp_mst_branch *mstb);
  83
  84 static void
  85 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  86                                    struct drm_dp_mst_branch *mstb);
  87
  88 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  89                                            struct drm_dp_mst_branch *mstb,
  90                                            struct drm_dp_mst_port *port);
  91 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  92                                  u8 *guid);
  93
  94 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  95 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  96 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  97
  98 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  99                                                  struct drm_dp_mst_branch *branch);
 100
 101 #define DBG_PREFIX "[dp_mst]"
 102
 103 #define DP_STR(x) [DP_ ## x] = #x
 104
 105 static const char *drm_dp_mst_req_type_str(u8 req_type)
 106 {
 107         static const char * const req_type_str[] = {
 108                 DP_STR(GET_MSG_TRANSACTION_VERSION),
 109                 DP_STR(LINK_ADDRESS),
 110                 DP_STR(CONNECTION_STATUS_NOTIFY),
 111                 DP_STR(ENUM_PATH_RESOURCES),
 112                 DP_STR(ALLOCATE_PAYLOAD),
 113                 DP_STR(QUERY_PAYLOAD),
 114                 DP_STR(RESOURCE_STATUS_NOTIFY),
 115                 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 116                 DP_STR(REMOTE_DPCD_READ),
 117                 DP_STR(REMOTE_DPCD_WRITE),
 118                 DP_STR(REMOTE_I2C_READ),
 119                 DP_STR(REMOTE_I2C_WRITE),
 120                 DP_STR(POWER_UP_PHY),
 121                 DP_STR(POWER_DOWN_PHY),
 122                 DP_STR(SINK_EVENT_NOTIFY),
 123                 DP_STR(QUERY_STREAM_ENC_STATUS),
 124         };
 125
 126         if (req_type >= ARRAY_SIZE(req_type_str) ||
 127             !req_type_str[req_type])
 128                 return "unknown";
 129
 130         return req_type_str[req_type];
 131 }
 132
 133 #undef DP_STR
 134 #define DP_STR(x) [DP_NAK_ ## x] = #x
 135
 136 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 137 {
 138         static const char * const nak_reason_str[] = {
 139                 DP_STR(WRITE_FAILURE),
 140                 DP_STR(INVALID_READ),
 141                 DP_STR(CRC_FAILURE),
 142                 DP_STR(BAD_PARAM),
 143                 DP_STR(DEFER),
 144                 DP_STR(LINK_FAILURE),
 145                 DP_STR(NO_RESOURCES),
 146                 DP_STR(DPCD_FAIL),
 147                 DP_STR(I2C_NAK),
 148                 DP_STR(ALLOCATE_FAIL),
 149         };
 150
 151         if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 152             !nak_reason_str[nak_reason])
 153                 return "unknown";
 154
 155         return nak_reason_str[nak_reason];
 156 }
 157
 158 #undef DP_STR
 159 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 160
 161 static const char *drm_dp_mst_sideband_tx_state_str(int state)
 162 {
 163         static const char * const sideband_reason_str[] = {
 164                 DP_STR(QUEUED),
 165                 DP_STR(START_SEND),
 166                 DP_STR(SENT),
 167                 DP_STR(RX),
 168                 DP_STR(TIMEOUT),
 169         };
 170
 171         if (state >= ARRAY_SIZE(sideband_reason_str) ||
 172             !sideband_reason_str[state])
 173                 return "unknown";
 174
 175         return sideband_reason_str[state];
 176 }
 177
 178 static int
 179 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 180 {
 181         int i;
 182         u8 unpacked_rad[16];
 183
 184         for (i = 0; i < lct; i++) {
 185                 if (i % 2)
 186                         unpacked_rad[i] = rad[i / 2] >> 4;
 187                 else
 188                         unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 189         }
 190
 191         /* TODO: Eventually add something to printk so we can format the rad
 192          * like this: 1.2.3
 193          */
 194         return snprintf(out, len, "%*phC", lct, unpacked_rad);
 195 }
 196
 197 /* sideband msg handling */
 198 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 199 {
 200         u8 bitmask = 0x80;
 201         u8 bitshift = 7;
 202         u8 array_index = 0;
 203         int number_of_bits = num_nibbles * 4;
 204         u8 remainder = 0;
 205
 206         while (number_of_bits != 0) {
 207                 number_of_bits--;
 208                 remainder <<= 1;
 209                 remainder |= (data[array_index] & bitmask) >> bitshift;
 210                 bitmask >>= 1;
 211                 bitshift--;
 212                 if (bitmask == 0) {
 213                         bitmask = 0x80;
 214                         bitshift = 7;
 215                         array_index++;
 216                 }
 217                 if ((remainder & 0x10) == 0x10)
 218                         remainder ^= 0x13;
 219         }
 220
 221         number_of_bits = 4;
 222         while (number_of_bits != 0) {
 223                 number_of_bits--;
 224                 remainder <<= 1;
 225                 if ((remainder & 0x10) != 0)
 226                         remainder ^= 0x13;
 227         }
 228
 229         return remainder;
 230 }
 231
 232 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 233 {
 234         u8 bitmask = 0x80;
 235         u8 bitshift = 7;
 236         u8 array_index = 0;
 237         int number_of_bits = number_of_bytes * 8;
 238         u16 remainder = 0;
 239
 240         while (number_of_bits != 0) {
 241                 number_of_bits--;
 242                 remainder <<= 1;
 243                 remainder |= (data[array_index] & bitmask) >> bitshift;
 244                 bitmask >>= 1;
 245                 bitshift--;
 246                 if (bitmask == 0) {
 247                         bitmask = 0x80;
 248                         bitshift = 7;
 249                         array_index++;
 250                 }
 251                 if ((remainder & 0x100) == 0x100)
 252                         remainder ^= 0xd5;
 253         }
 254
 255         number_of_bits = 8;
 256         while (number_of_bits != 0) {
 257                 number_of_bits--;
 258                 remainder <<= 1;
 259                 if ((remainder & 0x100) != 0)
 260                         remainder ^= 0xd5;
 261         }
 262
 263         return remainder & 0xff;
 264 }
 265 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 266 {
 267         u8 size = 3;
 268
 269         size += (hdr->lct / 2);
 270         return size;
 271 }
 272
 273 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 274                                            u8 *buf, int *len)
 275 {
 276         int idx = 0;
 277         int i;
 278         u8 crc4;
 279
 280         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 281         for (i = 0; i < (hdr->lct / 2); i++)
 282                 buf[idx++] = hdr->rad[i];
 283         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 284                 (hdr->msg_len & 0x3f);
 285         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 286
 287         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 288         buf[idx - 1] |= (crc4 & 0xf);
 289
 290         *len = idx;
 291 }
 292
 293 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 294                                            struct drm_dp_sideband_msg_hdr *hdr,
 295                                            u8 *buf, int buflen, u8 *hdrlen)
 296 {
 297         u8 crc4;
 298         u8 len;
 299         int i;
 300         u8 idx;
 301
 302         if (buf[0] == 0)
 303                 return false;
 304         len = 3;
 305         len += ((buf[0] & 0xf0) >> 4) / 2;
 306         if (len > buflen)
 307                 return false;
 308         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 309
 310         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 311                 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 312                 return false;
 313         }
 314
 315         hdr->lct = (buf[0] & 0xf0) >> 4;
 316         hdr->lcr = (buf[0] & 0xf);
 317         idx = 1;
 318         for (i = 0; i < (hdr->lct / 2); i++)
 319                 hdr->rad[i] = buf[idx++];
 320         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 321         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 322         hdr->msg_len = buf[idx] & 0x3f;
 323         idx++;
 324         hdr->somt = (buf[idx] >> 7) & 0x1;
 325         hdr->eomt = (buf[idx] >> 6) & 0x1;
 326         hdr->seqno = (buf[idx] >> 4) & 0x1;
 327         idx++;
 328         *hdrlen = idx;
 329         return true;
 330 }
 331
 332 void
 333 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 334                            struct drm_dp_sideband_msg_tx *raw)
 335 {
 336         int idx = 0;
 337         int i;
 338         u8 *buf = raw->msg;
 339
 340         buf[idx++] = req->req_type & 0x7f;
 341
 342         switch (req->req_type) {
 343         case DP_ENUM_PATH_RESOURCES:
 344         case DP_POWER_DOWN_PHY:
 345         case DP_POWER_UP_PHY:
 346                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 347                 idx++;
 348                 break;
 349         case DP_ALLOCATE_PAYLOAD:
 350                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 351                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 352                 idx++;
 353                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 354                 idx++;
 355                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 356                 idx++;
 357                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 358                 idx++;
 359                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 360                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 361                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 362                         idx++;
 363                 }
 364                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 365                         i = req->u.allocate_payload.number_sdp_streams - 1;
 366                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 367                         idx++;
 368                 }
 369                 break;
 370         case DP_QUERY_PAYLOAD:
 371                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 372                 idx++;
 373                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 374                 idx++;
 375                 break;
 376         case DP_REMOTE_DPCD_READ:
 377                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 378                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 379                 idx++;
 380                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 381                 idx++;
 382                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 383                 idx++;
 384                 buf[idx] = (req->u.dpcd_read.num_bytes);
 385                 idx++;
 386                 break;
 387
 388         case DP_REMOTE_DPCD_WRITE:
 389                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 390                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 391                 idx++;
 392                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 393                 idx++;
 394                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 395                 idx++;
 396                 buf[idx] = (req->u.dpcd_write.num_bytes);
 397                 idx++;
 398                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 399                 idx += req->u.dpcd_write.num_bytes;
 400                 break;
 401         case DP_REMOTE_I2C_READ:
 402                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 403                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 404                 idx++;
 405                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 406                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 407                         idx++;
 408                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 409                         idx++;
 410                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 411                         idx += req->u.i2c_read.transactions[i].num_bytes;
 412
 413                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 414                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 415                         idx++;
 416                 }
 417                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 418                 idx++;
 419                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 420                 idx++;
 421                 break;
 422
 423         case DP_REMOTE_I2C_WRITE:
 424                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 425                 idx++;
 426                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 427                 idx++;
 428                 buf[idx] = (req->u.i2c_write.num_bytes);
 429                 idx++;
 430                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 431                 idx += req->u.i2c_write.num_bytes;
 432                 break;
 433         case DP_QUERY_STREAM_ENC_STATUS: {
 434                 const struct drm_dp_query_stream_enc_status *msg;
 435
 436                 msg = &req->u.enc_status;
 437                 buf[idx] = msg->stream_id;
 438                 idx++;
 439                 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 440                 idx += sizeof(msg->client_id);
 441                 buf[idx] = 0;
 442                 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 443                 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 444                 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 445                 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 446                 idx++;
 447                 }
 448                 break;
 449         }
 450         raw->cur_len = idx;
 451 }
 452 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 453
 454 /* Decode a sideband request we've encoded, mainly used for debugging */
 455 int
 456 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 457                            struct drm_dp_sideband_msg_req_body *req)
 458 {
 459         const u8 *buf = raw->msg;
 460         int i, idx = 0;
 461
 462         req->req_type = buf[idx++] & 0x7f;
 463         switch (req->req_type) {
 464         case DP_ENUM_PATH_RESOURCES:
 465         case DP_POWER_DOWN_PHY:
 466         case DP_POWER_UP_PHY:
 467                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 468                 break;
 469         case DP_ALLOCATE_PAYLOAD:
 470                 {
 471                         struct drm_dp_allocate_payload *a =
 472                                 &req->u.allocate_payload;
 473
 474                         a->number_sdp_streams = buf[idx] & 0xf;
 475                         a->port_number = (buf[idx] >> 4) & 0xf;
 476
 477                         WARN_ON(buf[++idx] & 0x80);
 478                         a->vcpi = buf[idx] & 0x7f;
 479
 480                         a->pbn = buf[++idx] << 8;
 481                         a->pbn |= buf[++idx];
 482
 483                         idx++;
 484                         for (i = 0; i < a->number_sdp_streams; i++) {
 485                                 a->sdp_stream_sink[i] =
 486                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 487                         }
 488                 }
 489                 break;
 490         case DP_QUERY_PAYLOAD:
 491                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 492                 WARN_ON(buf[++idx] & 0x80);
 493                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 494                 break;
 495         case DP_REMOTE_DPCD_READ:
 496                 {
 497                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 498
 499                         r->port_number = (buf[idx] >> 4) & 0xf;
 500
 501                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 502                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 503                         r->dpcd_address |= buf[++idx] & 0xff;
 504
 505                         r->num_bytes = buf[++idx];
 506                 }
 507                 break;
 508         case DP_REMOTE_DPCD_WRITE:
 509                 {
 510                         struct drm_dp_remote_dpcd_write *w =
 511                                 &req->u.dpcd_write;
 512
 513                         w->port_number = (buf[idx] >> 4) & 0xf;
 514
 515                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 516                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 517                         w->dpcd_address |= buf[++idx] & 0xff;
 518
 519                         w->num_bytes = buf[++idx];
 520
 521                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 522                                            GFP_KERNEL);
 523                         if (!w->bytes)
 524                                 return -ENOMEM;
 525                 }
 526                 break;
 527         case DP_REMOTE_I2C_READ:
 528                 {
 529                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 530                         struct drm_dp_remote_i2c_read_tx *tx;
 531                         bool failed = false;
 532
 533                         r->num_transactions = buf[idx] & 0x3;
 534                         r->port_number = (buf[idx] >> 4) & 0xf;
 535                         for (i = 0; i < r->num_transactions; i++) {
 536                                 tx = &r->transactions[i];
 537
 538                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 539                                 tx->num_bytes = buf[++idx];
 540                                 tx->bytes = kmemdup(&buf[++idx],
 541                                                     tx->num_bytes,
 542                                                     GFP_KERNEL);
 543                                 if (!tx->bytes) {
 544                                         failed = true;
 545                                         break;
 546                                 }
 547                                 idx += tx->num_bytes;
 548                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 549                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 550                         }
 551
 552                         if (failed) {
 553                                 for (i = 0; i < r->num_transactions; i++) {
 554                                         tx = &r->transactions[i];
 555                                         kfree(tx->bytes);
 556                                 }
 557                                 return -ENOMEM;
 558                         }
 559
 560                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 561                         r->num_bytes_read = buf[++idx];
 562                 }
 563                 break;
 564         case DP_REMOTE_I2C_WRITE:
 565                 {
 566                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 567
 568                         w->port_number = (buf[idx] >> 4) & 0xf;
 569                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 570                         w->num_bytes = buf[++idx];
 571                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 572                                            GFP_KERNEL);
 573                         if (!w->bytes)
 574                                 return -ENOMEM;
 575                 }
 576                 break;
 577         case DP_QUERY_STREAM_ENC_STATUS:
 578                 req->u.enc_status.stream_id = buf[idx++];
 579                 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 580                         req->u.enc_status.client_id[i] = buf[idx++];
 581
 582                 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 583                                                            buf[idx]);
 584                 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 585                                                                  buf[idx]);
 586                 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 587                                                               buf[idx]);
 588                 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 589                                                                     buf[idx]);
 590                 break;
 591         }
 592
 593         return 0;
 594 }
 595 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 596
 597 void
 598 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 599                                   int indent, struct drm_printer *printer)
 600 {
 601         int i;
 602
 603 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 604         if (req->req_type == DP_LINK_ADDRESS) {
 605                 /* No contents to print */
 606                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 607                 return;
 608         }
 609
 610         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 611         indent++;
 612
 613         switch (req->req_type) {
 614         case DP_ENUM_PATH_RESOURCES:
 615         case DP_POWER_DOWN_PHY:
 616         case DP_POWER_UP_PHY:
 617                 P("port=%d\n", req->u.port_num.port_number);
 618                 break;
 619         case DP_ALLOCATE_PAYLOAD:
 620                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 621                   req->u.allocate_payload.port_number,
 622                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 623                   req->u.allocate_payload.number_sdp_streams,
 624                   req->u.allocate_payload.number_sdp_streams,
 625                   req->u.allocate_payload.sdp_stream_sink);
 626                 break;
 627         case DP_QUERY_PAYLOAD:
 628                 P("port=%d vcpi=%d\n",
 629                   req->u.query_payload.port_number,
 630                   req->u.query_payload.vcpi);
 631                 break;
 632         case DP_REMOTE_DPCD_READ:
 633                 P("port=%d dpcd_addr=%05x len=%d\n",
 634                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 635                   req->u.dpcd_read.num_bytes);
 636                 break;
 637         case DP_REMOTE_DPCD_WRITE:
 638                 P("port=%d addr=%05x len=%d: %*ph\n",
 639                   req->u.dpcd_write.port_number,
 640                   req->u.dpcd_write.dpcd_address,
 641                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 642                   req->u.dpcd_write.bytes);
 643                 break;
 644         case DP_REMOTE_I2C_READ:
 645                 P("port=%d num_tx=%d id=%d size=%d:\n",
 646                   req->u.i2c_read.port_number,
 647                   req->u.i2c_read.num_transactions,
 648                   req->u.i2c_read.read_i2c_device_id,
 649                   req->u.i2c_read.num_bytes_read);
 650
 651                 indent++;
 652                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 653                         const struct drm_dp_remote_i2c_read_tx *rtx =
 654                                 &req->u.i2c_read.transactions[i];
 655
 656                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 657                           i, rtx->i2c_dev_id, rtx->num_bytes,
 658                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 659                           rtx->num_bytes, rtx->bytes);
 660                 }
 661                 break;
 662         case DP_REMOTE_I2C_WRITE:
 663                 P("port=%d id=%d size=%d: %*ph\n",
 664                   req->u.i2c_write.port_number,
 665                   req->u.i2c_write.write_i2c_device_id,
 666                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 667                   req->u.i2c_write.bytes);
 668                 break;
 669         case DP_QUERY_STREAM_ENC_STATUS:
 670                 P("stream_id=%u client_id=%*ph stream_event=%x "
 671                   "valid_event=%d stream_behavior=%x valid_behavior=%d",
 672                   req->u.enc_status.stream_id,
 673                   (int)ARRAY_SIZE(req->u.enc_status.client_id),
 674                   req->u.enc_status.client_id, req->u.enc_status.stream_event,
 675                   req->u.enc_status.valid_stream_event,
 676                   req->u.enc_status.stream_behavior,
 677                   req->u.enc_status.valid_stream_behavior);
 678                 break;
 679         default:
 680                 P("???\n");
 681                 break;
 682         }
 683 #undef P
 684 }
 685 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 686
 687 static inline void
 688 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 689                                 const struct drm_dp_sideband_msg_tx *txmsg)
 690 {
 691         struct drm_dp_sideband_msg_req_body req;
 692         char buf[64];
 693         int ret;
 694         int i;
 695
 696         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 697                               sizeof(buf));
 698         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 699                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 700                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 701                    txmsg->path_msg, buf);
 702
 703         ret = drm_dp_decode_sideband_req(txmsg, &req);
 704         if (ret) {
 705                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 706                 return;
 707         }
 708         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 709
 710         switch (req.req_type) {
 711         case DP_REMOTE_DPCD_WRITE:
 712                 kfree(req.u.dpcd_write.bytes);
 713                 break;
 714         case DP_REMOTE_I2C_READ:
 715                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 716                         kfree(req.u.i2c_read.transactions[i].bytes);
 717                 break;
 718         case DP_REMOTE_I2C_WRITE:
 719                 kfree(req.u.i2c_write.bytes);
 720                 break;
 721         }
 722 }
 723
 724 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 725 {
 726         u8 crc4;
 727
 728         crc4 = drm_dp_msg_data_crc4(msg, len);
 729         msg[len] = crc4;
 730 }
 731
 732 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 733                                          struct drm_dp_sideband_msg_tx *raw)
 734 {
 735         int idx = 0;
 736         u8 *buf = raw->msg;
 737
 738         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 739
 740         raw->cur_len = idx;
 741 }
 742
 743 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 744                                           struct drm_dp_sideband_msg_hdr *hdr,
 745                                           u8 hdrlen)
 746 {
 747         /*
 748          * ignore out-of-order messages or messages that are part of a
 749          * failed transaction
 750          */
 751         if (!hdr->somt && !msg->have_somt)
 752                 return false;
 753
 754         /* get length contained in this portion */
 755         msg->curchunk_idx = 0;
 756         msg->curchunk_len = hdr->msg_len;
 757         msg->curchunk_hdrlen = hdrlen;
 758
 759         /* we have already gotten an somt - don't bother parsing */
 760         if (hdr->somt && msg->have_somt)
 761                 return false;
 762
 763         if (hdr->somt) {
 764                 memcpy(&msg->initial_hdr, hdr,
 765                        sizeof(struct drm_dp_sideband_msg_hdr));
 766                 msg->have_somt = true;
 767         }
 768         if (hdr->eomt)
 769                 msg->have_eomt = true;
 770
 771         return true;
 772 }
 773
 774 /* this adds a chunk of msg to the builder to get the final msg */
 775 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 776                                            u8 *replybuf, u8 replybuflen)
 777 {
 778         u8 crc4;
 779
 780         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 781         msg->curchunk_idx += replybuflen;
 782
 783         if (msg->curchunk_idx >= msg->curchunk_len) {
 784                 /* do CRC */
 785                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 786                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 787                         print_hex_dump(KERN_DEBUG, "wrong crc",
 788                                        DUMP_PREFIX_NONE, 16, 1,
 789                                        msg->chunk,  msg->curchunk_len, false);
 790                 /* copy chunk into bigger msg */
 791                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 792                 msg->curlen += msg->curchunk_len - 1;
 793         }
 794         return true;
 795 }
 796
 797 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 798                                                struct drm_dp_sideband_msg_rx *raw,
 799                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 800 {
 801         int idx = 1;
 802         int i;
 803
 804         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 805         idx += 16;
 806         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 807         idx++;
 808         if (idx > raw->curlen)
 809                 goto fail_len;
 810         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 811                 if (raw->msg[idx] & 0x80)
 812                         repmsg->u.link_addr.ports[i].input_port = 1;
 813
 814                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 815                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 816
 817                 idx++;
 818                 if (idx > raw->curlen)
 819                         goto fail_len;
 820                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 821                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 822                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 823                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 824                 idx++;
 825                 if (idx > raw->curlen)
 826                         goto fail_len;
 827                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 828                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 829                         idx++;
 830                         if (idx > raw->curlen)
 831                                 goto fail_len;
 832                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 833                         idx += 16;
 834                         if (idx > raw->curlen)
 835                                 goto fail_len;
 836                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 837                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 838                         idx++;
 839
 840                 }
 841                 if (idx > raw->curlen)
 842                         goto fail_len;
 843         }
 844
 845         return true;
 846 fail_len:
 847         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 848         return false;
 849 }
 850
 851 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 852                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 853 {
 854         int idx = 1;
 855
 856         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 857         idx++;
 858         if (idx > raw->curlen)
 859                 goto fail_len;
 860         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 861         idx++;
 862         if (idx > raw->curlen)
 863                 goto fail_len;
 864
 865         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 866         return true;
 867 fail_len:
 868         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 869         return false;
 870 }
 871
 872 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 873                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 874 {
 875         int idx = 1;
 876
 877         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 878         idx++;
 879         if (idx > raw->curlen)
 880                 goto fail_len;
 881         return true;
 882 fail_len:
 883         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 884         return false;
 885 }
 886
 887 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 888                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 889 {
 890         int idx = 1;
 891
 892         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 893         idx++;
 894         if (idx > raw->curlen)
 895                 goto fail_len;
 896         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 897         idx++;
 898         /* TODO check */
 899         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 900         return true;
 901 fail_len:
 902         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 903         return false;
 904 }
 905
 906 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 907                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 908 {
 909         int idx = 1;
 910
 911         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 912         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 913         idx++;
 914         if (idx > raw->curlen)
 915                 goto fail_len;
 916         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 917         idx += 2;
 918         if (idx > raw->curlen)
 919                 goto fail_len;
 920         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 921         idx += 2;
 922         if (idx > raw->curlen)
 923                 goto fail_len;
 924         return true;
 925 fail_len:
 926         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 927         return false;
 928 }
 929
 930 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 931                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 932 {
 933         int idx = 1;
 934
 935         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 936         idx++;
 937         if (idx > raw->curlen)
 938                 goto fail_len;
 939         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 940         idx++;
 941         if (idx > raw->curlen)
 942                 goto fail_len;
 943         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 944         idx += 2;
 945         if (idx > raw->curlen)
 946                 goto fail_len;
 947         return true;
 948 fail_len:
 949         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 950         return false;
 951 }
 952
 953 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 954                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 955 {
 956         int idx = 1;
 957
 958         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 959         idx++;
 960         if (idx > raw->curlen)
 961                 goto fail_len;
 962         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 963         idx += 2;
 964         if (idx > raw->curlen)
 965                 goto fail_len;
 966         return true;
 967 fail_len:
 968         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 969         return false;
 970 }
 971
 972 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 973                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 974 {
 975         int idx = 1;
 976
 977         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 978         idx++;
 979         if (idx > raw->curlen) {
 980                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 981                               idx, raw->curlen);
 982                 return false;
 983         }
 984         return true;
 985 }
 986
 987 static bool
 988 drm_dp_sideband_parse_query_stream_enc_status(
 989                                 struct drm_dp_sideband_msg_rx *raw,
 990                                 struct drm_dp_sideband_msg_reply_body *repmsg)
 991 {
 992         struct drm_dp_query_stream_enc_status_ack_reply *reply;
 993
 994         reply = &repmsg->u.enc_status;
 995
 996         reply->stream_id = raw->msg[3];
 997
 998         reply->reply_signed = raw->msg[2] & BIT(0);
 999
1000         /*
1001          * NOTE: It's my impression from reading the spec that the below parsing
1002          * is correct. However I noticed while testing with an HDCP 1.4 display
1003          * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1004          * would expect both bits to be set. So keep the parsing following the
1005          * spec, but beware reality might not match the spec (at least for some
1006          * configurations).
1007          */
1008         reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1009         reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1010
1011         reply->query_capable_device_present = raw->msg[2] & BIT(5);
1012         reply->legacy_device_present = raw->msg[2] & BIT(6);
1013         reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1014
1015         reply->auth_completed = !!(raw->msg[1] & BIT(3));
1016         reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1017         reply->repeater_present = !!(raw->msg[1] & BIT(5));
1018         reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1019
1020         return true;
1021 }
1022
1023 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1024                                         struct drm_dp_sideband_msg_rx *raw,
1025                                         struct drm_dp_sideband_msg_reply_body *msg)
1026 {
1027         memset(msg, 0, sizeof(*msg));
1028         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1029         msg->req_type = (raw->msg[0] & 0x7f);
1030
1031         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1032                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1033                 msg->u.nak.reason = raw->msg[17];
1034                 msg->u.nak.nak_data = raw->msg[18];
1035                 return false;
1036         }
1037
1038         switch (msg->req_type) {
1039         case DP_LINK_ADDRESS:
1040                 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1041         case DP_QUERY_PAYLOAD:
1042                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1043         case DP_REMOTE_DPCD_READ:
1044                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1045         case DP_REMOTE_DPCD_WRITE:
1046                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1047         case DP_REMOTE_I2C_READ:
1048                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1049         case DP_REMOTE_I2C_WRITE:
1050                 return true; /* since there's nothing to parse */
1051         case DP_ENUM_PATH_RESOURCES:
1052                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1053         case DP_ALLOCATE_PAYLOAD:
1054                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1055         case DP_POWER_DOWN_PHY:
1056         case DP_POWER_UP_PHY:
1057                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1058         case DP_CLEAR_PAYLOAD_ID_TABLE:
1059                 return true; /* since there's nothing to parse */
1060         case DP_QUERY_STREAM_ENC_STATUS:
1061                 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1062         default:
1063                 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1064                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1065                 return false;
1066         }
1067 }
1068
1069 static bool
1070 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1071                                                struct drm_dp_sideband_msg_rx *raw,
1072                                                struct drm_dp_sideband_msg_req_body *msg)
1073 {
1074         int idx = 1;
1075
1076         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1077         idx++;
1078         if (idx > raw->curlen)
1079                 goto fail_len;
1080
1081         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1082         idx += 16;
1083         if (idx > raw->curlen)
1084                 goto fail_len;
1085
1086         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1087         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1088         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1089         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1090         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1091         idx++;
1092         return true;
1093 fail_len:
1094         drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1095                     idx, raw->curlen);
1096         return false;
1097 }
1098
1099 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1100                                                          struct drm_dp_sideband_msg_rx *raw,
1101                                                          struct drm_dp_sideband_msg_req_body *msg)
1102 {
1103         int idx = 1;
1104
1105         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1106         idx++;
1107         if (idx > raw->curlen)
1108                 goto fail_len;
1109
1110         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1111         idx += 16;
1112         if (idx > raw->curlen)
1113                 goto fail_len;
1114
1115         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1116         idx++;
1117         return true;
1118 fail_len:
1119         drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1120         return false;
1121 }
1122
1123 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1124                                       struct drm_dp_sideband_msg_rx *raw,
1125                                       struct drm_dp_sideband_msg_req_body *msg)
1126 {
1127         memset(msg, 0, sizeof(*msg));
1128         msg->req_type = (raw->msg[0] & 0x7f);
1129
1130         switch (msg->req_type) {
1131         case DP_CONNECTION_STATUS_NOTIFY:
1132                 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1133         case DP_RESOURCE_STATUS_NOTIFY:
1134                 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1135         default:
1136                 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1137                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1138                 return false;
1139         }
1140 }
1141
1142 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1143                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1144 {
1145         struct drm_dp_sideband_msg_req_body req;
1146
1147         req.req_type = DP_REMOTE_DPCD_WRITE;
1148         req.u.dpcd_write.port_number = port_num;
1149         req.u.dpcd_write.dpcd_address = offset;
1150         req.u.dpcd_write.num_bytes = num_bytes;
1151         req.u.dpcd_write.bytes = bytes;
1152         drm_dp_encode_sideband_req(&req, msg);
1153 }
1154
1155 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1156 {
1157         struct drm_dp_sideband_msg_req_body req;
1158
1159         req.req_type = DP_LINK_ADDRESS;
1160         drm_dp_encode_sideband_req(&req, msg);
1161 }
1162
1163 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1164 {
1165         struct drm_dp_sideband_msg_req_body req;
1166
1167         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1168         drm_dp_encode_sideband_req(&req, msg);
1169         msg->path_msg = true;
1170 }
1171
1172 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1173                                      int port_num)
1174 {
1175         struct drm_dp_sideband_msg_req_body req;
1176
1177         req.req_type = DP_ENUM_PATH_RESOURCES;
1178         req.u.port_num.port_number = port_num;
1179         drm_dp_encode_sideband_req(&req, msg);
1180         msg->path_msg = true;
1181         return 0;
1182 }
1183
1184 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1185                                    int port_num,
1186                                    u8 vcpi, uint16_t pbn,
1187                                    u8 number_sdp_streams,
1188                                    u8 *sdp_stream_sink)
1189 {
1190         struct drm_dp_sideband_msg_req_body req;
1191
1192         memset(&req, 0, sizeof(req));
1193         req.req_type = DP_ALLOCATE_PAYLOAD;
1194         req.u.allocate_payload.port_number = port_num;
1195         req.u.allocate_payload.vcpi = vcpi;
1196         req.u.allocate_payload.pbn = pbn;
1197         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1198         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1199                    number_sdp_streams);
1200         drm_dp_encode_sideband_req(&req, msg);
1201         msg->path_msg = true;
1202 }
1203
1204 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1205                                    int port_num, bool power_up)
1206 {
1207         struct drm_dp_sideband_msg_req_body req;
1208
1209         if (power_up)
1210                 req.req_type = DP_POWER_UP_PHY;
1211         else
1212                 req.req_type = DP_POWER_DOWN_PHY;
1213
1214         req.u.port_num.port_number = port_num;
1215         drm_dp_encode_sideband_req(&req, msg);
1216         msg->path_msg = true;
1217 }
1218
1219 static int
1220 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1221                               u8 *q_id)
1222 {
1223         struct drm_dp_sideband_msg_req_body req;
1224
1225         req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1226         req.u.enc_status.stream_id = stream_id;
1227         memcpy(req.u.enc_status.client_id, q_id,
1228                sizeof(req.u.enc_status.client_id));
1229         req.u.enc_status.stream_event = 0;
1230         req.u.enc_status.valid_stream_event = false;
1231         req.u.enc_status.stream_behavior = 0;
1232         req.u.enc_status.valid_stream_behavior = false;
1233
1234         drm_dp_encode_sideband_req(&req, msg);
1235         return 0;
1236 }
1237
1238 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1239                                         struct drm_dp_vcpi *vcpi)
1240 {
1241         int ret, vcpi_ret;
1242
1243         mutex_lock(&mgr->payload_lock);
1244         ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1245         if (ret > mgr->max_payloads) {
1246                 ret = -EINVAL;
1247                 drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
1248                 goto out_unlock;
1249         }
1250
1251         vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1252         if (vcpi_ret > mgr->max_payloads) {
1253                 ret = -EINVAL;
1254                 drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
1255                 goto out_unlock;
1256         }
1257
1258         set_bit(ret, &mgr->payload_mask);
1259         set_bit(vcpi_ret, &mgr->vcpi_mask);
1260         vcpi->vcpi = vcpi_ret + 1;
1261         mgr->proposed_vcpis[ret - 1] = vcpi;
1262 out_unlock:
1263         mutex_unlock(&mgr->payload_lock);
1264         return ret;
1265 }
1266
1267 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1268                                       int vcpi)
1269 {
1270         int i;
1271
1272         if (vcpi == 0)
1273                 return;
1274
1275         mutex_lock(&mgr->payload_lock);
1276         drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
1277         clear_bit(vcpi - 1, &mgr->vcpi_mask);
1278
1279         for (i = 0; i < mgr->max_payloads; i++) {
1280                 if (mgr->proposed_vcpis[i] &&
1281                     mgr->proposed_vcpis[i]->vcpi == vcpi) {
1282                         mgr->proposed_vcpis[i] = NULL;
1283                         clear_bit(i + 1, &mgr->payload_mask);
1284                 }
1285         }
1286         mutex_unlock(&mgr->payload_lock);
1287 }
1288
1289 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1290                               struct drm_dp_sideband_msg_tx *txmsg)
1291 {
1292         unsigned int state;
1293
1294         /*
1295          * All updates to txmsg->state are protected by mgr->qlock, and the two
1296          * cases we check here are terminal states. For those the barriers
1297          * provided by the wake_up/wait_event pair are enough.
1298          */
1299         state = READ_ONCE(txmsg->state);
1300         return (state == DRM_DP_SIDEBAND_TX_RX ||
1301                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1302 }
1303
1304 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1305                                     struct drm_dp_sideband_msg_tx *txmsg)
1306 {
1307         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1308         unsigned long wait_timeout = msecs_to_jiffies(4000);
1309         unsigned long wait_expires = jiffies + wait_timeout;
1310         int ret;
1311
1312         for (;;) {
1313                 /*
1314                  * If the driver provides a way for this, change to
1315                  * poll-waiting for the MST reply interrupt if we didn't receive
1316                  * it for 50 msec. This would cater for cases where the HPD
1317                  * pulse signal got lost somewhere, even though the sink raised
1318                  * the corresponding MST interrupt correctly. One example is the
1319                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1320                  * filters out short pulses with a duration less than ~540 usec.
1321                  *
1322                  * The poll period is 50 msec to avoid missing an interrupt
1323                  * after the sink has cleared it (after a 110msec timeout
1324                  * since it raised the interrupt).
1325                  */
1326                 ret = wait_event_timeout(mgr->tx_waitq,
1327                                          check_txmsg_state(mgr, txmsg),
1328                                          mgr->cbs->poll_hpd_irq ?
1329                                                 msecs_to_jiffies(50) :
1330                                                 wait_timeout);
1331
1332                 if (ret || !mgr->cbs->poll_hpd_irq ||
1333                     time_after(jiffies, wait_expires))
1334                         break;
1335
1336                 mgr->cbs->poll_hpd_irq(mgr);
1337         }
1338
1339         mutex_lock(&mgr->qlock);
1340         if (ret > 0) {
1341                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1342                         ret = -EIO;
1343                         goto out;
1344                 }
1345         } else {
1346                 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1347                             txmsg, txmsg->state, txmsg->seqno);
1348
1349                 /* dump some state */
1350                 ret = -EIO;
1351
1352                 /* remove from q */
1353                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1354                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1355                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1356                         list_del(&txmsg->next);
1357         }
1358 out:
1359         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1360                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1361
1362                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1363         }
1364         mutex_unlock(&mgr->qlock);
1365
1366         drm_dp_mst_kick_tx(mgr);
1367         return ret;
1368 }
1369
1370 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1371 {
1372         struct drm_dp_mst_branch *mstb;
1373
1374         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1375         if (!mstb)
1376                 return NULL;
1377
1378         mstb->lct = lct;
1379         if (lct > 1)
1380                 memcpy(mstb->rad, rad, lct / 2);
1381         INIT_LIST_HEAD(&mstb->ports);
1382         kref_init(&mstb->topology_kref);
1383         kref_init(&mstb->malloc_kref);
1384         return mstb;
1385 }
1386
1387 static void drm_dp_free_mst_branch_device(struct kref *kref)
1388 {
1389         struct drm_dp_mst_branch *mstb =
1390                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1391
1392         if (mstb->port_parent)
1393                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1394
1395         kfree(mstb);
1396 }
1397
1398 /**
1399  * DOC: Branch device and port refcounting
1400  *
1401  * Topology refcount overview
1402  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1403  *
1404  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1405  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1406  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1407  *
1408  * Topology refcounts are not exposed to drivers, and are handled internally
1409  * by the DP MST helpers. The helpers use them in order to prevent the
1410  * in-memory topology state from being changed in the middle of critical
1411  * operations like changing the internal state of payload allocations. This
1412  * means each branch and port will be considered to be connected to the rest
1413  * of the topology until its topology refcount reaches zero. Additionally,
1414  * for ports this means that their associated &struct drm_connector will stay
1415  * registered with userspace until the port's refcount reaches 0.
1416  *
1417  * Malloc refcount overview
1418  * ~~~~~~~~~~~~~~~~~~~~~~~~
1419  *
1420  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1421  * drm_dp_mst_branch allocated even after all of its topology references have
1422  * been dropped, so that the driver or MST helpers can safely access each
1423  * branch's last known state before it was disconnected from the topology.
1424  * When the malloc refcount of a port or branch reaches 0, the memory
1425  * allocation containing the &struct drm_dp_mst_branch or &struct
1426  * drm_dp_mst_port respectively will be freed.
1427  *
1428  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1429  * to drivers. As of writing this documentation, there are no drivers that
1430  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1431  * helpers. Exposing this API to drivers in a race-free manner would take more
1432  * tweaking of the refcounting scheme, however patches are welcome provided
1433  * there is a legitimate driver usecase for this.
1434  *
1435  * Refcount relationships in a topology
1436  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1437  *
1438  * Let's take a look at why the relationship between topology and malloc
1439  * refcounts is designed the way it is.
1440  *
1441  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1442  *
1443  *    An example of topology and malloc refs in a DP MST topology with two
1444  *    active payloads. Topology refcount increments are indicated by solid
1445  *    lines, and malloc refcount increments are indicated by dashed lines.
1446  *    Each starts from the branch which incremented the refcount, and ends at
1447  *    the branch to which the refcount belongs to, i.e. the arrow points the
1448  *    same way as the C pointers used to reference a structure.
1449  *
1450  * As you can see in the above figure, every branch increments the topology
1451  * refcount of its children, and increments the malloc refcount of its
1452  * parent. Additionally, every payload increments the malloc refcount of its
1453  * assigned port by 1.
1454  *
1455  * So, what would happen if MSTB #3 from the above figure was unplugged from
1456  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1457  * topology would start to look like the figure below.
1458  *
1459  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1460  *
1461  *    Ports and branch devices which have been released from memory are
1462  *    colored grey, and references which have been removed are colored red.
1463  *
1464  * Whenever a port or branch device's topology refcount reaches zero, it will
1465  * decrement the topology refcounts of all its children, the malloc refcount
1466  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1467  * #4, this means they both have been disconnected from the topology and freed
1468  * from memory. But, because payload #2 is still holding a reference to port
1469  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1470  * is still accessible from memory. This also means port #3 has not yet
1471  * decremented the malloc refcount of MSTB #3, so its &struct
1472  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1473  * malloc refcount reaches 0.
1474  *
1475  * This relationship is necessary because in order to release payload #2, we
1476  * need to be able to figure out the last relative of port #3 that's still
1477  * connected to the topology. In this case, we would travel up the topology as
1478  * shown below.
1479  *
1480  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1481  *
1482  * And finally, remove payload #2 by communicating with port #2 through
1483  * sideband transactions.
1484  */
1485
1486 /**
1487  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1488  * device
1489  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1490  *
1491  * Increments &drm_dp_mst_branch.malloc_kref. When
1492  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1493  * will be released and @mstb may no longer be used.
1494  *
1495  * See also: drm_dp_mst_put_mstb_malloc()
1496  */
1497 static void
1498 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1499 {
1500         kref_get(&mstb->malloc_kref);
1501         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1502 }
1503
1504 /**
1505  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1506  * device
1507  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1508  *
1509  * Decrements &drm_dp_mst_branch.malloc_kref. When
1510  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1511  * will be released and @mstb may no longer be used.
1512  *
1513  * See also: drm_dp_mst_get_mstb_malloc()
1514  */
1515 static void
1516 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1517 {
1518         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1519         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1520 }
1521
1522 static void drm_dp_free_mst_port(struct kref *kref)
1523 {
1524         struct drm_dp_mst_port *port =
1525                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1526
1527         drm_dp_mst_put_mstb_malloc(port->parent);
1528         kfree(port);
1529 }
1530
1531 /**
1532  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1533  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1534  *
1535  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1536  * reaches 0, the memory allocation for @port will be released and @port may
1537  * no longer be used.
1538  *
1539  * Because @port could potentially be freed at any time by the DP MST helpers
1540  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1541  * function, drivers that which to make use of &struct drm_dp_mst_port should
1542  * ensure that they grab at least one main malloc reference to their MST ports
1543  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1544  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1545  *
1546  * See also: drm_dp_mst_put_port_malloc()
1547  */
1548 void
1549 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1550 {
1551         kref_get(&port->malloc_kref);
1552         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1553 }
1554 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1555
1556 /**
1557  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1558  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1559  *
1560  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1561  * reaches 0, the memory allocation for @port will be released and @port may
1562  * no longer be used.
1563  *
1564  * See also: drm_dp_mst_get_port_malloc()
1565  */
1566 void
1567 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1568 {
1569         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1570         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1571 }
1572 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1573
1574 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1575
1576 #define STACK_DEPTH 8
1577
1578 static noinline void
1579 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1580                     struct drm_dp_mst_topology_ref_history *history,
1581                     enum drm_dp_mst_topology_ref_type type)
1582 {
1583         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1584         depot_stack_handle_t backtrace;
1585         ulong stack_entries[STACK_DEPTH];
1586         uint n;
1587         int i;
1588
1589         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1590         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1591         if (!backtrace)
1592                 return;
1593
1594         /* Try to find an existing entry for this backtrace */
1595         for (i = 0; i < history->len; i++) {
1596                 if (history->entries[i].backtrace == backtrace) {
1597                         entry = &history->entries[i];
1598                         break;
1599                 }
1600         }
1601
1602         /* Otherwise add one */
1603         if (!entry) {
1604                 struct drm_dp_mst_topology_ref_entry *new;
1605                 int new_len = history->len + 1;
1606
1607                 new = krealloc(history->entries, sizeof(*new) * new_len,
1608                                GFP_KERNEL);
1609                 if (!new)
1610                         return;
1611
1612                 entry = &new[history->len];
1613                 history->len = new_len;
1614                 history->entries = new;
1615
1616                 entry->backtrace = backtrace;
1617                 entry->type = type;
1618                 entry->count = 0;
1619         }
1620         entry->count++;
1621         entry->ts_nsec = ktime_get_ns();
1622 }
1623
1624 static int
1625 topology_ref_history_cmp(const void *a, const void *b)
1626 {
1627         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1628
1629         if (entry_a->ts_nsec > entry_b->ts_nsec)
1630                 return 1;
1631         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1632                 return -1;
1633         else
1634                 return 0;
1635 }
1636
1637 static inline const char *
1638 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1639 {
1640         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1641                 return "get";
1642         else
1643                 return "put";
1644 }
1645
1646 static void
1647 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1648                             void *ptr, const char *type_str)
1649 {
1650         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1651         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1652         int i;
1653
1654         if (!buf)
1655                 return;
1656
1657         if (!history->len)
1658                 goto out;
1659
1660         /* First, sort the list so that it goes from oldest to newest
1661          * reference entry
1662          */
1663         sort(history->entries, history->len, sizeof(*history->entries),
1664              topology_ref_history_cmp, NULL);
1665
1666         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1667                    type_str, ptr);
1668
1669         for (i = 0; i < history->len; i++) {
1670                 const struct drm_dp_mst_topology_ref_entry *entry =
1671                         &history->entries[i];
1672                 u64 ts_nsec = entry->ts_nsec;
1673                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1674
1675                 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1676
1677                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1678                            entry->count,
1679                            topology_ref_type_to_str(entry->type),
1680                            ts_nsec, rem_nsec / 1000, buf);
1681         }
1682
1683         /* Now free the history, since this is the only time we expose it */
1684         kfree(history->entries);
1685 out:
1686         kfree(buf);
1687 }
1688
1689 static __always_inline void
1690 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1691 {
1692         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1693                                     "MSTB");
1694 }
1695
1696 static __always_inline void
1697 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1698 {
1699         __dump_topology_ref_history(&port->topology_ref_history, port,
1700                                     "Port");
1701 }
1702
1703 static __always_inline void
1704 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1705                        enum drm_dp_mst_topology_ref_type type)
1706 {
1707         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1708 }
1709
1710 static __always_inline void
1711 save_port_topology_ref(struct drm_dp_mst_port *port,
1712                        enum drm_dp_mst_topology_ref_type type)
1713 {
1714         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1715 }
1716
1717 static inline void
1718 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1719 {
1720         mutex_lock(&mgr->topology_ref_history_lock);
1721 }
1722
1723 static inline void
1724 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1725 {
1726         mutex_unlock(&mgr->topology_ref_history_lock);
1727 }
1728 #else
1729 static inline void
1730 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1731 static inline void
1732 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1733 static inline void
1734 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1735 static inline void
1736 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1737 #define save_mstb_topology_ref(mstb, type)
1738 #define save_port_topology_ref(port, type)
1739 #endif
1740
1741 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1742 {
1743         struct drm_dp_mst_branch *mstb =
1744                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1745         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1746
1747         drm_dp_mst_dump_mstb_topology_history(mstb);
1748
1749         INIT_LIST_HEAD(&mstb->destroy_next);
1750
1751         /*
1752          * This can get called under mgr->mutex, so we need to perform the
1753          * actual destruction of the mstb in another worker
1754          */
1755         mutex_lock(&mgr->delayed_destroy_lock);
1756         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1757         mutex_unlock(&mgr->delayed_destroy_lock);
1758         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1759 }
1760
1761 /**
1762  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1763  * branch device unless it's zero
1764  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1765  *
1766  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1767  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1768  * reached 0). Holding a topology reference implies that a malloc reference
1769  * will be held to @mstb as long as the user holds the topology reference.
1770  *
1771  * Care should be taken to ensure that the user has at least one malloc
1772  * reference to @mstb. If you already have a topology reference to @mstb, you
1773  * should use drm_dp_mst_topology_get_mstb() instead.
1774  *
1775  * See also:
1776  * drm_dp_mst_topology_get_mstb()
1777  * drm_dp_mst_topology_put_mstb()
1778  *
1779  * Returns:
1780  * * 1: A topology reference was grabbed successfully
1781  * * 0: @port is no longer in the topology, no reference was grabbed
1782  */
1783 static int __must_check
1784 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1785 {
1786         int ret;
1787
1788         topology_ref_history_lock(mstb->mgr);
1789         ret = kref_get_unless_zero(&mstb->topology_kref);
1790         if (ret) {
1791                 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1792                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1793         }
1794
1795         topology_ref_history_unlock(mstb->mgr);
1796
1797         return ret;
1798 }
1799
1800 /**
1801  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1802  * branch device
1803  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1804  *
1805  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1806  * not it's already reached 0. This is only valid to use in scenarios where
1807  * you are already guaranteed to have at least one active topology reference
1808  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1809  *
1810  * See also:
1811  * drm_dp_mst_topology_try_get_mstb()
1812  * drm_dp_mst_topology_put_mstb()
1813  */
1814 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1815 {
1816         topology_ref_history_lock(mstb->mgr);
1817
1818         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1819         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1820         kref_get(&mstb->topology_kref);
1821         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1822
1823         topology_ref_history_unlock(mstb->mgr);
1824 }
1825
1826 /**
1827  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1828  * device
1829  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1830  *
1831  * Releases a topology reference from @mstb by decrementing
1832  * &drm_dp_mst_branch.topology_kref.
1833  *
1834  * See also:
1835  * drm_dp_mst_topology_try_get_mstb()
1836  * drm_dp_mst_topology_get_mstb()
1837  */
1838 static void
1839 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1840 {
1841         topology_ref_history_lock(mstb->mgr);
1842
1843         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1844         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1845
1846         topology_ref_history_unlock(mstb->mgr);
1847         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1848 }
1849
1850 static void drm_dp_destroy_port(struct kref *kref)
1851 {
1852         struct drm_dp_mst_port *port =
1853                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1854         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1855
1856         drm_dp_mst_dump_port_topology_history(port);
1857
1858         /* There's nothing that needs locking to destroy an input port yet */
1859         if (port->input) {
1860                 drm_dp_mst_put_port_malloc(port);
1861                 return;
1862         }
1863
1864         kfree(port->cached_edid);
1865
1866         /*
1867          * we can't destroy the connector here, as we might be holding the
1868          * mode_config.mutex from an EDID retrieval
1869          */
1870         mutex_lock(&mgr->delayed_destroy_lock);
1871         list_add(&port->next, &mgr->destroy_port_list);
1872         mutex_unlock(&mgr->delayed_destroy_lock);
1873         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1874 }
1875
1876 /**
1877  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1878  * port unless it's zero
1879  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1880  *
1881  * Attempts to grab a topology reference to @port, if it hasn't yet been
1882  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1883  * 0). Holding a topology reference implies that a malloc reference will be
1884  * held to @port as long as the user holds the topology reference.
1885  *
1886  * Care should be taken to ensure that the user has at least one malloc
1887  * reference to @port. If you already have a topology reference to @port, you
1888  * should use drm_dp_mst_topology_get_port() instead.
1889  *
1890  * See also:
1891  * drm_dp_mst_topology_get_port()
1892  * drm_dp_mst_topology_put_port()
1893  *
1894  * Returns:
1895  * * 1: A topology reference was grabbed successfully
1896  * * 0: @port is no longer in the topology, no reference was grabbed
1897  */
1898 static int __must_check
1899 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1900 {
1901         int ret;
1902
1903         topology_ref_history_lock(port->mgr);
1904         ret = kref_get_unless_zero(&port->topology_kref);
1905         if (ret) {
1906                 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1907                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1908         }
1909
1910         topology_ref_history_unlock(port->mgr);
1911         return ret;
1912 }
1913
1914 /**
1915  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1916  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1917  *
1918  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1919  * not it's already reached 0. This is only valid to use in scenarios where
1920  * you are already guaranteed to have at least one active topology reference
1921  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1922  *
1923  * See also:
1924  * drm_dp_mst_topology_try_get_port()
1925  * drm_dp_mst_topology_put_port()
1926  */
1927 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1928 {
1929         topology_ref_history_lock(port->mgr);
1930
1931         WARN_ON(kref_read(&port->topology_kref) == 0);
1932         kref_get(&port->topology_kref);
1933         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1934         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1935
1936         topology_ref_history_unlock(port->mgr);
1937 }
1938
1939 /**
1940  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1941  * @port: The &struct drm_dp_mst_port to release the topology reference from
1942  *
1943  * Releases a topology reference from @port by decrementing
1944  * &drm_dp_mst_port.topology_kref.
1945  *
1946  * See also:
1947  * drm_dp_mst_topology_try_get_port()
1948  * drm_dp_mst_topology_get_port()
1949  */
1950 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1951 {
1952         topology_ref_history_lock(port->mgr);
1953
1954         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1955         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1956
1957         topology_ref_history_unlock(port->mgr);
1958         kref_put(&port->topology_kref, drm_dp_destroy_port);
1959 }
1960
1961 static struct drm_dp_mst_branch *
1962 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1963                                               struct drm_dp_mst_branch *to_find)
1964 {
1965         struct drm_dp_mst_port *port;
1966         struct drm_dp_mst_branch *rmstb;
1967
1968         if (to_find == mstb)
1969                 return mstb;
1970
1971         list_for_each_entry(port, &mstb->ports, next) {
1972                 if (port->mstb) {
1973                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1974                             port->mstb, to_find);
1975                         if (rmstb)
1976                                 return rmstb;
1977                 }
1978         }
1979         return NULL;
1980 }
1981
1982 static struct drm_dp_mst_branch *
1983 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1984                                        struct drm_dp_mst_branch *mstb)
1985 {
1986         struct drm_dp_mst_branch *rmstb = NULL;
1987
1988         mutex_lock(&mgr->lock);
1989         if (mgr->mst_primary) {
1990                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1991                     mgr->mst_primary, mstb);
1992
1993                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1994                         rmstb = NULL;
1995         }
1996         mutex_unlock(&mgr->lock);
1997         return rmstb;
1998 }
1999
2000 static struct drm_dp_mst_port *
2001 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
2002                                               struct drm_dp_mst_port *to_find)
2003 {
2004         struct drm_dp_mst_port *port, *mport;
2005
2006         list_for_each_entry(port, &mstb->ports, next) {
2007                 if (port == to_find)
2008                         return port;
2009
2010                 if (port->mstb) {
2011                         mport = drm_dp_mst_topology_get_port_validated_locked(
2012                             port->mstb, to_find);
2013                         if (mport)
2014                                 return mport;
2015                 }
2016         }
2017         return NULL;
2018 }
2019
2020 static struct drm_dp_mst_port *
2021 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2022                                        struct drm_dp_mst_port *port)
2023 {
2024         struct drm_dp_mst_port *rport = NULL;
2025
2026         mutex_lock(&mgr->lock);
2027         if (mgr->mst_primary) {
2028                 rport = drm_dp_mst_topology_get_port_validated_locked(
2029                     mgr->mst_primary, port);
2030
2031                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
2032                         rport = NULL;
2033         }
2034         mutex_unlock(&mgr->lock);
2035         return rport;
2036 }
2037
2038 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2039 {
2040         struct drm_dp_mst_port *port;
2041         int ret;
2042
2043         list_for_each_entry(port, &mstb->ports, next) {
2044                 if (port->port_num == port_num) {
2045                         ret = drm_dp_mst_topology_try_get_port(port);
2046                         return ret ? port : NULL;
2047                 }
2048         }
2049
2050         return NULL;
2051 }
2052
2053 /*
2054  * calculate a new RAD for this MST branch device
2055  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2056  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2057  */
2058 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2059                                  u8 *rad)
2060 {
2061         int parent_lct = port->parent->lct;
2062         int shift = 4;
2063         int idx = (parent_lct - 1) / 2;
2064
2065         if (parent_lct > 1) {
2066                 memcpy(rad, port->parent->rad, idx + 1);
2067                 shift = (parent_lct % 2) ? 4 : 0;
2068         } else
2069                 rad[0] = 0;
2070
2071         rad[idx] |= port->port_num << shift;
2072         return parent_lct + 1;
2073 }
2074
2075 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2076 {
2077         switch (pdt) {
2078         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2079         case DP_PEER_DEVICE_SST_SINK:
2080                 return true;
2081         case DP_PEER_DEVICE_MST_BRANCHING:
2082                 /* For sst branch device */
2083                 if (!mcs)
2084                         return true;
2085
2086                 return false;
2087         }
2088         return true;
2089 }
2090
2091 static int
2092 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2093                     bool new_mcs)
2094 {
2095         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2096         struct drm_dp_mst_branch *mstb;
2097         u8 rad[8], lct;
2098         int ret = 0;
2099
2100         if (port->pdt == new_pdt && port->mcs == new_mcs)
2101                 return 0;
2102
2103         /* Teardown the old pdt, if there is one */
2104         if (port->pdt != DP_PEER_DEVICE_NONE) {
2105                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2106                         /*
2107                          * If the new PDT would also have an i2c bus,
2108                          * don't bother with reregistering it
2109                          */
2110                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2111                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2112                                 port->pdt = new_pdt;
2113                                 port->mcs = new_mcs;
2114                                 return 0;
2115                         }
2116
2117                         /* remove i2c over sideband */
2118                         drm_dp_mst_unregister_i2c_bus(port);
2119                 } else {
2120                         mutex_lock(&mgr->lock);
2121                         drm_dp_mst_topology_put_mstb(port->mstb);
2122                         port->mstb = NULL;
2123                         mutex_unlock(&mgr->lock);
2124                 }
2125         }
2126
2127         port->pdt = new_pdt;
2128         port->mcs = new_mcs;
2129
2130         if (port->pdt != DP_PEER_DEVICE_NONE) {
2131                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2132                         /* add i2c over sideband */
2133                         ret = drm_dp_mst_register_i2c_bus(port);
2134                 } else {
2135                         lct = drm_dp_calculate_rad(port, rad);
2136                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2137                         if (!mstb) {
2138                                 ret = -ENOMEM;
2139                                 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2140                                 goto out;
2141                         }
2142
2143                         mutex_lock(&mgr->lock);
2144                         port->mstb = mstb;
2145                         mstb->mgr = port->mgr;
2146                         mstb->port_parent = port;
2147
2148                         /*
2149                          * Make sure this port's memory allocation stays
2150                          * around until its child MSTB releases it
2151                          */
2152                         drm_dp_mst_get_port_malloc(port);
2153                         mutex_unlock(&mgr->lock);
2154
2155                         /* And make sure we send a link address for this */
2156                         ret = 1;
2157                 }
2158         }
2159
2160 out:
2161         if (ret < 0)
2162                 port->pdt = DP_PEER_DEVICE_NONE;
2163         return ret;
2164 }
2165
2166 /**
2167  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2168  * @aux: Fake sideband AUX CH
2169  * @offset: address of the (first) register to read
2170  * @buffer: buffer to store the register values
2171  * @size: number of bytes in @buffer
2172  *
2173  * Performs the same functionality for remote devices via
2174  * sideband messaging as drm_dp_dpcd_read() does for local
2175  * devices via actual AUX CH.
2176  *
2177  * Return: Number of bytes read, or negative error code on failure.
2178  */
2179 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2180                              unsigned int offset, void *buffer, size_t size)
2181 {
2182         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2183                                                     aux);
2184
2185         return drm_dp_send_dpcd_read(port->mgr, port,
2186                                      offset, size, buffer);
2187 }
2188
2189 /**
2190  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2191  * @aux: Fake sideband AUX CH
2192  * @offset: address of the (first) register to write
2193  * @buffer: buffer containing the values to write
2194  * @size: number of bytes in @buffer
2195  *
2196  * Performs the same functionality for remote devices via
2197  * sideband messaging as drm_dp_dpcd_write() does for local
2198  * devices via actual AUX CH.
2199  *
2200  * Return: number of bytes written on success, negative error code on failure.
2201  */
2202 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2203                               unsigned int offset, void *buffer, size_t size)
2204 {
2205         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2206                                                     aux);
2207
2208         return drm_dp_send_dpcd_write(port->mgr, port,
2209                                       offset, size, buffer);
2210 }
2211
2212 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2213 {
2214         int ret = 0;
2215
2216         memcpy(mstb->guid, guid, 16);
2217
2218         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2219                 if (mstb->port_parent) {
2220                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2221                                                      mstb->port_parent,
2222                                                      DP_GUID, 16, mstb->guid);
2223                 } else {
2224                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2225                                                 DP_GUID, mstb->guid, 16);
2226                 }
2227         }
2228
2229         if (ret < 16 && ret > 0)
2230                 return -EPROTO;
2231
2232         return ret == 16 ? 0 : ret;
2233 }
2234
2235 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2236                                 int pnum,
2237                                 char *proppath,
2238                                 size_t proppath_size)
2239 {
2240         int i;
2241         char temp[8];
2242
2243         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2244         for (i = 0; i < (mstb->lct - 1); i++) {
2245                 int shift = (i % 2) ? 0 : 4;
2246                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2247
2248                 snprintf(temp, sizeof(temp), "-%d", port_num);
2249                 strlcat(proppath, temp, proppath_size);
2250         }
2251         snprintf(temp, sizeof(temp), "-%d", pnum);
2252         strlcat(proppath, temp, proppath_size);
2253 }
2254
2255 /**
2256  * drm_dp_mst_connector_late_register() - Late MST connector registration
2257  * @connector: The MST connector
2258  * @port: The MST port for this connector
2259  *
2260  * Helper to register the remote aux device for this MST port. Drivers should
2261  * call this from their mst connector's late_register hook to enable MST aux
2262  * devices.
2263  *
2264  * Return: 0 on success, negative error code on failure.
2265  */
2266 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2267                                        struct drm_dp_mst_port *port)
2268 {
2269         drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2270                     port->aux.name, connector->kdev->kobj.name);
2271
2272         port->aux.dev = connector->kdev;
2273         return drm_dp_aux_register_devnode(&port->aux);
2274 }
2275 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2276
2277 /**
2278  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2279  * @connector: The MST connector
2280  * @port: The MST port for this connector
2281  *
2282  * Helper to unregister the remote aux device for this MST port, registered by
2283  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2284  * connector's early_unregister hook.
2285  */
2286 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2287                                            struct drm_dp_mst_port *port)
2288 {
2289         drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2290                     port->aux.name, connector->kdev->kobj.name);
2291         drm_dp_aux_unregister_devnode(&port->aux);
2292 }
2293 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2294
2295 static void
2296 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2297                               struct drm_dp_mst_port *port)
2298 {
2299         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2300         char proppath[255];
2301         int ret;
2302
2303         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2304         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2305         if (!port->connector) {
2306                 ret = -ENOMEM;
2307                 goto error;
2308         }
2309
2310         if (port->pdt != DP_PEER_DEVICE_NONE &&
2311             drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2312             port->port_num >= DP_MST_LOGICAL_PORT_0)
2313                 port->cached_edid = drm_get_edid(port->connector,
2314                                                  &port->aux.ddc);
2315
2316         drm_connector_register(port->connector);
2317         return;
2318
2319 error:
2320         drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2321 }
2322
2323 /*
2324  * Drop a topology reference, and unlink the port from the in-memory topology
2325  * layout
2326  */
2327 static void
2328 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2329                                 struct drm_dp_mst_port *port)
2330 {
2331         mutex_lock(&mgr->lock);
2332         port->parent->num_ports--;
2333         list_del(&port->next);
2334         mutex_unlock(&mgr->lock);
2335         drm_dp_mst_topology_put_port(port);
2336 }
2337
2338 static struct drm_dp_mst_port *
2339 drm_dp_mst_add_port(struct drm_device *dev,
2340                     struct drm_dp_mst_topology_mgr *mgr,
2341                     struct drm_dp_mst_branch *mstb, u8 port_number)
2342 {
2343         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2344
2345         if (!port)
2346                 return NULL;
2347
2348         kref_init(&port->topology_kref);
2349         kref_init(&port->malloc_kref);
2350         port->parent = mstb;
2351         port->port_num = port_number;
2352         port->mgr = mgr;
2353         port->aux.name = "DPMST";
2354         port->aux.dev = dev->dev;
2355         port->aux.is_remote = true;
2356
2357         /* initialize the MST downstream port's AUX crc work queue */
2358         port->aux.drm_dev = dev;
2359         drm_dp_remote_aux_init(&port->aux);
2360
2361         /*
2362          * Make sure the memory allocation for our parent branch stays
2363          * around until our own memory allocation is released
2364          */
2365         drm_dp_mst_get_mstb_malloc(mstb);
2366
2367         return port;
2368 }
2369
2370 static int
2371 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2372                                     struct drm_device *dev,
2373                                     struct drm_dp_link_addr_reply_port *port_msg)
2374 {
2375         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2376         struct drm_dp_mst_port *port;
2377         int old_ddps = 0, ret;
2378         u8 new_pdt = DP_PEER_DEVICE_NONE;
2379         bool new_mcs = 0;
2380         bool created = false, send_link_addr = false, changed = false;
2381
2382         port = drm_dp_get_port(mstb, port_msg->port_number);
2383         if (!port) {
2384                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2385                                            port_msg->port_number);
2386                 if (!port)
2387                         return -ENOMEM;
2388                 created = true;
2389                 changed = true;
2390         } else if (!port->input && port_msg->input_port && port->connector) {
2391                 /* Since port->connector can't be changed here, we create a
2392                  * new port if input_port changes from 0 to 1
2393                  */
2394                 drm_dp_mst_topology_unlink_port(mgr, port);
2395                 drm_dp_mst_topology_put_port(port);
2396                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2397                                            port_msg->port_number);
2398                 if (!port)
2399                         return -ENOMEM;
2400                 changed = true;
2401                 created = true;
2402         } else if (port->input && !port_msg->input_port) {
2403                 changed = true;
2404         } else if (port->connector) {
2405                 /* We're updating a port that's exposed to userspace, so do it
2406                  * under lock
2407                  */
2408                 drm_modeset_lock(&mgr->base.lock, NULL);
2409
2410                 old_ddps = port->ddps;
2411                 changed = port->ddps != port_msg->ddps ||
2412                         (port->ddps &&
2413                          (port->ldps != port_msg->legacy_device_plug_status ||
2414                           port->dpcd_rev != port_msg->dpcd_revision ||
2415                           port->mcs != port_msg->mcs ||
2416                           port->pdt != port_msg->peer_device_type ||
2417                           port->num_sdp_stream_sinks !=
2418                           port_msg->num_sdp_stream_sinks));
2419         }
2420
2421         port->input = port_msg->input_port;
2422         if (!port->input)
2423                 new_pdt = port_msg->peer_device_type;
2424         new_mcs = port_msg->mcs;
2425         port->ddps = port_msg->ddps;
2426         port->ldps = port_msg->legacy_device_plug_status;
2427         port->dpcd_rev = port_msg->dpcd_revision;
2428         port->num_sdp_streams = port_msg->num_sdp_streams;
2429         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2430
2431         /* manage mstb port lists with mgr lock - take a reference
2432            for this list */
2433         if (created) {
2434                 mutex_lock(&mgr->lock);
2435                 drm_dp_mst_topology_get_port(port);
2436                 list_add(&port->next, &mstb->ports);
2437                 mstb->num_ports++;
2438                 mutex_unlock(&mgr->lock);
2439         }
2440
2441         /*
2442          * Reprobe PBN caps on both hotplug, and when re-probing the link
2443          * for our parent mstb
2444          */
2445         if (old_ddps != port->ddps || !created) {
2446                 if (port->ddps && !port->input) {
2447                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2448                                                               port);
2449                         if (ret == 1)
2450                                 changed = true;
2451                 } else {
2452                         port->full_pbn = 0;
2453                 }
2454         }
2455
2456         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2457         if (ret == 1) {
2458                 send_link_addr = true;
2459         } else if (ret < 0) {
2460                 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2461                 goto fail;
2462         }
2463
2464         /*
2465          * If this port wasn't just created, then we're reprobing because
2466          * we're coming out of suspend. In this case, always resend the link
2467          * address if there's an MSTB on this port
2468          */
2469         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2470             port->mcs)
2471                 send_link_addr = true;
2472
2473         if (port->connector)
2474                 drm_modeset_unlock(&mgr->base.lock);
2475         else if (!port->input)
2476                 drm_dp_mst_port_add_connector(mstb, port);
2477
2478         if (send_link_addr && port->mstb) {
2479                 ret = drm_dp_send_link_address(mgr, port->mstb);
2480                 if (ret == 1) /* MSTB below us changed */
2481                         changed = true;
2482                 else if (ret < 0)
2483                         goto fail_put;
2484         }
2485
2486         /* put reference to this port */
2487         drm_dp_mst_topology_put_port(port);
2488         return changed;
2489
2490 fail:
2491         drm_dp_mst_topology_unlink_port(mgr, port);
2492         if (port->connector)
2493                 drm_modeset_unlock(&mgr->base.lock);
2494 fail_put:
2495         drm_dp_mst_topology_put_port(port);
2496         return ret;
2497 }
2498
2499 static void
2500 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2501                             struct drm_dp_connection_status_notify *conn_stat)
2502 {
2503         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2504         struct drm_dp_mst_port *port;
2505         int old_ddps, ret;
2506         u8 new_pdt;
2507         bool new_mcs;
2508         bool dowork = false, create_connector = false;
2509
2510         port = drm_dp_get_port(mstb, conn_stat->port_number);
2511         if (!port)
2512                 return;
2513
2514         if (port->connector) {
2515                 if (!port->input && conn_stat->input_port) {
2516                         /*
2517                          * We can't remove a connector from an already exposed
2518                          * port, so just throw the port out and make sure we
2519                          * reprobe the link address of it's parent MSTB
2520                          */
2521                         drm_dp_mst_topology_unlink_port(mgr, port);
2522                         mstb->link_address_sent = false;
2523                         dowork = true;
2524                         goto out;
2525                 }
2526
2527                 /* Locking is only needed if the port's exposed to userspace */
2528                 drm_modeset_lock(&mgr->base.lock, NULL);
2529         } else if (port->input && !conn_stat->input_port) {
2530                 create_connector = true;
2531                 /* Reprobe link address so we get num_sdp_streams */
2532                 mstb->link_address_sent = false;
2533                 dowork = true;
2534         }
2535
2536         old_ddps = port->ddps;
2537         port->input = conn_stat->input_port;
2538         port->ldps = conn_stat->legacy_device_plug_status;
2539         port->ddps = conn_stat->displayport_device_plug_status;
2540
2541         if (old_ddps != port->ddps) {
2542                 if (port->ddps && !port->input)
2543                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2544                 else
2545                         port->full_pbn = 0;
2546         }
2547
2548         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2549         new_mcs = conn_stat->message_capability_status;
2550         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2551         if (ret == 1) {
2552                 dowork = true;
2553         } else if (ret < 0) {
2554                 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2555                 dowork = false;
2556         }
2557
2558         if (port->connector)
2559                 drm_modeset_unlock(&mgr->base.lock);
2560         else if (create_connector)
2561                 drm_dp_mst_port_add_connector(mstb, port);
2562
2563 out:
2564         drm_dp_mst_topology_put_port(port);
2565         if (dowork)
2566                 queue_work(system_long_wq, &mstb->mgr->work);
2567 }
2568
2569 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2570                                                                u8 lct, u8 *rad)
2571 {
2572         struct drm_dp_mst_branch *mstb;
2573         struct drm_dp_mst_port *port;
2574         int i, ret;
2575         /* find the port by iterating down */
2576
2577         mutex_lock(&mgr->lock);
2578         mstb = mgr->mst_primary;
2579
2580         if (!mstb)
2581                 goto out;
2582
2583         for (i = 0; i < lct - 1; i++) {
2584                 int shift = (i % 2) ? 0 : 4;
2585                 int port_num = (rad[i / 2] >> shift) & 0xf;
2586
2587                 list_for_each_entry(port, &mstb->ports, next) {
2588                         if (port->port_num == port_num) {
2589                                 mstb = port->mstb;
2590                                 if (!mstb) {
2591                                         drm_err(mgr->dev,
2592                                                 "failed to lookup MSTB with lct %d, rad %02x\n",
2593                                                 lct, rad[0]);
2594                                         goto out;
2595                                 }
2596
2597                                 break;
2598                         }
2599                 }
2600         }
2601         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2602         if (!ret)
2603                 mstb = NULL;
2604 out:
2605         mutex_unlock(&mgr->lock);
2606         return mstb;
2607 }
2608
2609 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2610         struct drm_dp_mst_branch *mstb,
2611         const uint8_t *guid)
2612 {
2613         struct drm_dp_mst_branch *found_mstb;
2614         struct drm_dp_mst_port *port;
2615
2616         if (memcmp(mstb->guid, guid, 16) == 0)
2617                 return mstb;
2618
2619
2620         list_for_each_entry(port, &mstb->ports, next) {
2621                 if (!port->mstb)
2622                         continue;
2623
2624                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2625
2626                 if (found_mstb)
2627                         return found_mstb;
2628         }
2629
2630         return NULL;
2631 }
2632
2633 static struct drm_dp_mst_branch *
2634 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2635                                      const uint8_t *guid)
2636 {
2637         struct drm_dp_mst_branch *mstb;
2638         int ret;
2639
2640         /* find the port by iterating down */
2641         mutex_lock(&mgr->lock);
2642
2643         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2644         if (mstb) {
2645                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2646                 if (!ret)
2647                         mstb = NULL;
2648         }
2649
2650         mutex_unlock(&mgr->lock);
2651         return mstb;
2652 }
2653
2654 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2655                                                struct drm_dp_mst_branch *mstb)
2656 {
2657         struct drm_dp_mst_port *port;
2658         int ret;
2659         bool changed = false;
2660
2661         if (!mstb->link_address_sent) {
2662                 ret = drm_dp_send_link_address(mgr, mstb);
2663                 if (ret == 1)
2664                         changed = true;
2665                 else if (ret < 0)
2666                         return ret;
2667         }
2668
2669         list_for_each_entry(port, &mstb->ports, next) {
2670                 if (port->input || !port->ddps || !port->mstb)
2671                         continue;
2672
2673                 ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2674                 if (ret == 1)
2675                         changed = true;
2676                 else if (ret < 0)
2677                         return ret;
2678         }
2679
2680         return changed;
2681 }
2682
2683 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2684 {
2685         struct drm_dp_mst_topology_mgr *mgr =
2686                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2687         struct drm_device *dev = mgr->dev;
2688         struct drm_dp_mst_branch *mstb;
2689         int ret;
2690         bool clear_payload_id_table;
2691
2692         mutex_lock(&mgr->probe_lock);
2693
2694         mutex_lock(&mgr->lock);
2695         clear_payload_id_table = !mgr->payload_id_table_cleared;
2696         mgr->payload_id_table_cleared = true;
2697
2698         mstb = mgr->mst_primary;
2699         if (mstb) {
2700                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2701                 if (!ret)
2702                         mstb = NULL;
2703         }
2704         mutex_unlock(&mgr->lock);
2705         if (!mstb) {
2706                 mutex_unlock(&mgr->probe_lock);
2707                 return;
2708         }
2709
2710         /*
2711          * Certain branch devices seem to incorrectly report an available_pbn
2712          * of 0 on downstream sinks, even after clearing the
2713          * DP_PAYLOAD_ALLOCATE_* registers in
2714          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2715          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2716          * things work again.
2717          */
2718         if (clear_payload_id_table) {
2719                 drm_dbg_kms(dev, "Clearing payload ID table\n");
2720                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2721         }
2722
2723         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2724         drm_dp_mst_topology_put_mstb(mstb);
2725
2726         mutex_unlock(&mgr->probe_lock);
2727         if (ret > 0)
2728                 drm_kms_helper_hotplug_event(dev);
2729 }
2730
2731 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2732                                  u8 *guid)
2733 {
2734         u64 salt;
2735
2736         if (memchr_inv(guid, 0, 16))
2737                 return true;
2738
2739         salt = get_jiffies_64();
2740
2741         memcpy(&guid[0], &salt, sizeof(u64));
2742         memcpy(&guid[8], &salt, sizeof(u64));
2743
2744         return false;
2745 }
2746
2747 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2748                             u8 port_num, u32 offset, u8 num_bytes)
2749 {
2750         struct drm_dp_sideband_msg_req_body req;
2751
2752         req.req_type = DP_REMOTE_DPCD_READ;
2753         req.u.dpcd_read.port_number = port_num;
2754         req.u.dpcd_read.dpcd_address = offset;
2755         req.u.dpcd_read.num_bytes = num_bytes;
2756         drm_dp_encode_sideband_req(&req, msg);
2757 }
2758
2759 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2760                                     bool up, u8 *msg, int len)
2761 {
2762         int ret;
2763         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2764         int tosend, total, offset;
2765         int retries = 0;
2766
2767 retry:
2768         total = len;
2769         offset = 0;
2770         do {
2771                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2772
2773                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2774                                         &msg[offset],
2775                                         tosend);
2776                 if (ret != tosend) {
2777                         if (ret == -EIO && retries < 5) {
2778                                 retries++;
2779                                 goto retry;
2780                         }
2781                         drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2782
2783                         return -EIO;
2784                 }
2785                 offset += tosend;
2786                 total -= tosend;
2787         } while (total > 0);
2788         return 0;
2789 }
2790
2791 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2792                                   struct drm_dp_sideband_msg_tx *txmsg)
2793 {
2794         struct drm_dp_mst_branch *mstb = txmsg->dst;
2795         u8 req_type;
2796
2797         req_type = txmsg->msg[0] & 0x7f;
2798         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2799                 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2800                 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2801                 hdr->broadcast = 1;
2802         else
2803                 hdr->broadcast = 0;
2804         hdr->path_msg = txmsg->path_msg;
2805         if (hdr->broadcast) {
2806                 hdr->lct = 1;
2807                 hdr->lcr = 6;
2808         } else {
2809                 hdr->lct = mstb->lct;
2810                 hdr->lcr = mstb->lct - 1;
2811         }
2812
2813         memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2814
2815         return 0;
2816 }
2817 /*
2818  * process a single block of the next message in the sideband queue
2819  */
2820 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2821                                    struct drm_dp_sideband_msg_tx *txmsg,
2822                                    bool up)
2823 {
2824         u8 chunk[48];
2825         struct drm_dp_sideband_msg_hdr hdr;
2826         int len, space, idx, tosend;
2827         int ret;
2828
2829         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2830                 return 0;
2831
2832         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2833
2834         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2835                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2836
2837         /* make hdr from dst mst */
2838         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2839         if (ret < 0)
2840                 return ret;
2841
2842         /* amount left to send in this message */
2843         len = txmsg->cur_len - txmsg->cur_offset;
2844
2845         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2846         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2847
2848         tosend = min(len, space);
2849         if (len == txmsg->cur_len)
2850                 hdr.somt = 1;
2851         if (space >= len)
2852                 hdr.eomt = 1;
2853
2854
2855         hdr.msg_len = tosend + 1;
2856         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2857         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2858         /* add crc at end */
2859         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2860         idx += tosend + 1;
2861
2862         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2863         if (ret) {
2864                 if (drm_debug_enabled(DRM_UT_DP)) {
2865                         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2866
2867                         drm_printf(&p, "sideband msg failed to send\n");
2868                         drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2869                 }
2870                 return ret;
2871         }
2872
2873         txmsg->cur_offset += tosend;
2874         if (txmsg->cur_offset == txmsg->cur_len) {
2875                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2876                 return 1;
2877         }
2878         return 0;
2879 }
2880
2881 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2882 {
2883         struct drm_dp_sideband_msg_tx *txmsg;
2884         int ret;
2885
2886         WARN_ON(!mutex_is_locked(&mgr->qlock));
2887
2888         /* construct a chunk from the first msg in the tx_msg queue */
2889         if (list_empty(&mgr->tx_msg_downq))
2890                 return;
2891
2892         txmsg = list_first_entry(&mgr->tx_msg_downq,
2893                                  struct drm_dp_sideband_msg_tx, next);
2894         ret = process_single_tx_qlock(mgr, txmsg, false);
2895         if (ret < 0) {
2896                 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2897                 list_del(&txmsg->next);
2898                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2899                 wake_up_all(&mgr->tx_waitq);
2900         }
2901 }
2902
2903 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2904                                  struct drm_dp_sideband_msg_tx *txmsg)
2905 {
2906         mutex_lock(&mgr->qlock);
2907         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2908
2909         if (drm_debug_enabled(DRM_UT_DP)) {
2910                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2911
2912                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2913         }
2914
2915         if (list_is_singular(&mgr->tx_msg_downq))
2916                 process_single_down_tx_qlock(mgr);
2917         mutex_unlock(&mgr->qlock);
2918 }
2919
2920 static void
2921 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2922                          struct drm_dp_link_address_ack_reply *reply)
2923 {
2924         struct drm_dp_link_addr_reply_port *port_reply;
2925         int i;
2926
2927         for (i = 0; i < reply->nports; i++) {
2928                 port_reply = &reply->ports[i];
2929                 drm_dbg_kms(mgr->dev,
2930                             "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2931                             i,
2932                             port_reply->input_port,
2933                             port_reply->peer_device_type,
2934                             port_reply->port_number,
2935                             port_reply->dpcd_revision,
2936                             port_reply->mcs,
2937                             port_reply->ddps,
2938                             port_reply->legacy_device_plug_status,
2939                             port_reply->num_sdp_streams,
2940                             port_reply->num_sdp_stream_sinks);
2941         }
2942 }
2943
2944 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2945                                      struct drm_dp_mst_branch *mstb)
2946 {
2947         struct drm_dp_sideband_msg_tx *txmsg;
2948         struct drm_dp_link_address_ack_reply *reply;
2949         struct drm_dp_mst_port *port, *tmp;
2950         int i, ret, port_mask = 0;
2951         bool changed = false;
2952
2953         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2954         if (!txmsg)
2955                 return -ENOMEM;
2956
2957         txmsg->dst = mstb;
2958         build_link_address(txmsg);
2959
2960         mstb->link_address_sent = true;
2961         drm_dp_queue_down_tx(mgr, txmsg);
2962
2963         /* FIXME: Actually do some real error handling here */
2964         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2965         if (ret <= 0) {
2966                 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2967                 goto out;
2968         }
2969         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2970                 drm_err(mgr->dev, "link address NAK received\n");
2971                 ret = -EIO;
2972                 goto out;
2973         }
2974
2975         reply = &txmsg->reply.u.link_addr;
2976         drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2977         drm_dp_dump_link_address(mgr, reply);
2978
2979         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2980         if (ret) {
2981                 char buf[64];
2982
2983                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2984                 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2985                 goto out;
2986         }
2987
2988         for (i = 0; i < reply->nports; i++) {
2989                 port_mask |= BIT(reply->ports[i].port_number);
2990                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2991                                                           &reply->ports[i]);
2992                 if (ret == 1)
2993                         changed = true;
2994                 else if (ret < 0)
2995                         goto out;
2996         }
2997
2998         /* Prune any ports that are currently a part of mstb in our in-memory
2999          * topology, but were not seen in this link address. Usually this
3000          * means that they were removed while the topology was out of sync,
3001          * e.g. during suspend/resume
3002          */
3003         mutex_lock(&mgr->lock);
3004         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3005                 if (port_mask & BIT(port->port_num))
3006                         continue;
3007
3008                 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
3009                             port->port_num);
3010                 list_del(&port->next);
3011                 drm_dp_mst_topology_put_port(port);
3012                 changed = true;
3013         }
3014         mutex_unlock(&mgr->lock);
3015
3016 out:
3017         if (ret <= 0)
3018                 mstb->link_address_sent = false;
3019         kfree(txmsg);
3020         return ret < 0 ? ret : changed;
3021 }
3022
3023 static void
3024 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3025                                    struct drm_dp_mst_branch *mstb)
3026 {
3027         struct drm_dp_sideband_msg_tx *txmsg;
3028         int ret;
3029
3030         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3031         if (!txmsg)
3032                 return;
3033
3034         txmsg->dst = mstb;
3035         build_clear_payload_id_table(txmsg);
3036
3037         drm_dp_queue_down_tx(mgr, txmsg);
3038
3039         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3040         if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3041                 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3042
3043         kfree(txmsg);
3044 }
3045
3046 static int
3047 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3048                                 struct drm_dp_mst_branch *mstb,
3049                                 struct drm_dp_mst_port *port)
3050 {
3051         struct drm_dp_enum_path_resources_ack_reply *path_res;
3052         struct drm_dp_sideband_msg_tx *txmsg;
3053         int ret;
3054
3055         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3056         if (!txmsg)
3057                 return -ENOMEM;
3058
3059         txmsg->dst = mstb;
3060         build_enum_path_resources(txmsg, port->port_num);
3061
3062         drm_dp_queue_down_tx(mgr, txmsg);
3063
3064         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3065         if (ret > 0) {
3066                 ret = 0;
3067                 path_res = &txmsg->reply.u.path_resources;
3068
3069                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3070                         drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3071                 } else {
3072                         if (port->port_num != path_res->port_number)
3073                                 DRM_ERROR("got incorrect port in response\n");
3074
3075                         drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3076                                     path_res->port_number,
3077                                     path_res->full_payload_bw_number,
3078                                     path_res->avail_payload_bw_number);
3079
3080                         /*
3081                          * If something changed, make sure we send a
3082                          * hotplug
3083                          */
3084                         if (port->full_pbn != path_res->full_payload_bw_number ||
3085                             port->fec_capable != path_res->fec_capable)
3086                                 ret = 1;
3087
3088                         port->full_pbn = path_res->full_payload_bw_number;
3089                         port->fec_capable = path_res->fec_capable;
3090                 }
3091         }
3092
3093         kfree(txmsg);
3094         return ret;
3095 }
3096
3097 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3098 {
3099         if (!mstb->port_parent)
3100                 return NULL;
3101
3102         if (mstb->port_parent->mstb != mstb)
3103                 return mstb->port_parent;
3104
3105         return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3106 }
3107
3108 /*
3109  * Searches upwards in the topology starting from mstb to try to find the
3110  * closest available parent of mstb that's still connected to the rest of the
3111  * topology. This can be used in order to perform operations like releasing
3112  * payloads, where the branch device which owned the payload may no longer be
3113  * around and thus would require that the payload on the last living relative
3114  * be freed instead.
3115  */
3116 static struct drm_dp_mst_branch *
3117 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3118                                         struct drm_dp_mst_branch *mstb,
3119                                         int *port_num)
3120 {
3121         struct drm_dp_mst_branch *rmstb = NULL;
3122         struct drm_dp_mst_port *found_port;
3123
3124         mutex_lock(&mgr->lock);
3125         if (!mgr->mst_primary)
3126                 goto out;
3127
3128         do {
3129                 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3130                 if (!found_port)
3131                         break;
3132
3133                 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3134                         rmstb = found_port->parent;
3135                         *port_num = found_port->port_num;
3136                 } else {
3137                         /* Search again, starting from this parent */
3138                         mstb = found_port->parent;
3139                 }
3140         } while (!rmstb);
3141 out:
3142         mutex_unlock(&mgr->lock);
3143         return rmstb;
3144 }
3145
3146 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3147                                    struct drm_dp_mst_port *port,
3148                                    int id,
3149                                    int pbn)
3150 {
3151         struct drm_dp_sideband_msg_tx *txmsg;
3152         struct drm_dp_mst_branch *mstb;
3153         int ret, port_num;
3154         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3155         int i;
3156
3157         port_num = port->port_num;
3158         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3159         if (!mstb) {
3160                 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3161                                                                port->parent,
3162                                                                &port_num);
3163
3164                 if (!mstb)
3165                         return -EINVAL;
3166         }
3167
3168         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3169         if (!txmsg) {
3170                 ret = -ENOMEM;
3171                 goto fail_put;
3172         }
3173
3174         for (i = 0; i < port->num_sdp_streams; i++)
3175                 sinks[i] = i;
3176
3177         txmsg->dst = mstb;
3178         build_allocate_payload(txmsg, port_num,
3179                                id,
3180                                pbn, port->num_sdp_streams, sinks);
3181
3182         drm_dp_queue_down_tx(mgr, txmsg);
3183
3184         /*
3185          * FIXME: there is a small chance that between getting the last
3186          * connected mstb and sending the payload message, the last connected
3187          * mstb could also be removed from the topology. In the future, this
3188          * needs to be fixed by restarting the
3189          * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3190          * timeout if the topology is still connected to the system.
3191          */
3192         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3193         if (ret > 0) {
3194                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3195                         ret = -EINVAL;
3196                 else
3197                         ret = 0;
3198         }
3199         kfree(txmsg);
3200 fail_put:
3201         drm_dp_mst_topology_put_mstb(mstb);
3202         return ret;
3203 }
3204
3205 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3206                                  struct drm_dp_mst_port *port, bool power_up)
3207 {
3208         struct drm_dp_sideband_msg_tx *txmsg;
3209         int ret;
3210
3211         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3212         if (!port)
3213                 return -EINVAL;
3214
3215         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3216         if (!txmsg) {
3217                 drm_dp_mst_topology_put_port(port);
3218                 return -ENOMEM;
3219         }
3220
3221         txmsg->dst = port->parent;
3222         build_power_updown_phy(txmsg, port->port_num, power_up);
3223         drm_dp_queue_down_tx(mgr, txmsg);
3224
3225         ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3226         if (ret > 0) {
3227                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3228                         ret = -EINVAL;
3229                 else
3230                         ret = 0;
3231         }
3232         kfree(txmsg);
3233         drm_dp_mst_topology_put_port(port);
3234
3235         return ret;
3236 }
3237 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3238
3239 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3240                 struct drm_dp_mst_port *port,
3241                 struct drm_dp_query_stream_enc_status_ack_reply *status)
3242 {
3243         struct drm_dp_sideband_msg_tx *txmsg;
3244         u8 nonce[7];
3245         int ret;
3246
3247         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3248         if (!txmsg)
3249                 return -ENOMEM;
3250
3251         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3252         if (!port) {
3253                 ret = -EINVAL;
3254                 goto out_get_port;
3255         }
3256
3257         get_random_bytes(nonce, sizeof(nonce));
3258
3259         /*
3260          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3261          *  transaction at the MST Branch device directly connected to the
3262          *  Source"
3263          */
3264         txmsg->dst = mgr->mst_primary;
3265
3266         build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3267
3268         drm_dp_queue_down_tx(mgr, txmsg);
3269
3270         ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3271         if (ret < 0) {
3272                 goto out;
3273         } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3274                 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3275                 ret = -ENXIO;
3276                 goto out;
3277         }
3278
3279         ret = 0;
3280         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3281
3282 out:
3283         drm_dp_mst_topology_put_port(port);
3284 out_get_port:
3285         kfree(txmsg);
3286         return ret;
3287 }
3288 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3289
3290 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3291                                        int id,
3292                                        struct drm_dp_payload *payload)
3293 {
3294         int ret;
3295
3296         ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3297         if (ret < 0) {
3298                 payload->payload_state = 0;
3299                 return ret;
3300         }
3301         payload->payload_state = DP_PAYLOAD_LOCAL;
3302         return 0;
3303 }
3304
3305 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3306                                        struct drm_dp_mst_port *port,
3307                                        int id,
3308                                        struct drm_dp_payload *payload)
3309 {
3310         int ret;
3311
3312         ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3313         if (ret < 0)
3314                 return ret;
3315         payload->payload_state = DP_PAYLOAD_REMOTE;
3316         return ret;
3317 }
3318
3319 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3320                                         struct drm_dp_mst_port *port,
3321                                         int id,
3322                                         struct drm_dp_payload *payload)
3323 {
3324         drm_dbg_kms(mgr->dev, "\n");
3325         /* it's okay for these to fail */
3326         if (port) {
3327                 drm_dp_payload_send_msg(mgr, port, id, 0);
3328         }
3329
3330         drm_dp_dpcd_write_payload(mgr, id, payload);
3331         payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3332         return 0;
3333 }
3334
3335 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3336                                         int id,
3337                                         struct drm_dp_payload *payload)
3338 {
3339         payload->payload_state = 0;
3340         return 0;
3341 }
3342
3343 /**
3344  * drm_dp_update_payload_part1() - Execute payload update part 1
3345  * @mgr: manager to use.
3346  * @start_slot: this is the cur slot
3347  *
3348  * NOTE: start_slot is a temporary workaround for non-atomic drivers,
3349  * this will be removed when non-atomic mst helpers are moved out of the helper
3350  *
3351  * This iterates over all proposed virtual channels, and tries to
3352  * allocate space in the link for them. For 0->slots transitions,
3353  * this step just writes the VCPI to the MST device. For slots->0
3354  * transitions, this writes the updated VCPIs and removes the
3355  * remote VC payloads.
3356  *
3357  * after calling this the driver should generate ACT and payload
3358  * packets.
3359  */
3360 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot)
3361 {
3362         struct drm_dp_payload req_payload;
3363         struct drm_dp_mst_port *port;
3364         int i, j;
3365         int cur_slots = start_slot;
3366         bool skip;
3367
3368         mutex_lock(&mgr->payload_lock);
3369         for (i = 0; i < mgr->max_payloads; i++) {
3370                 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3371                 struct drm_dp_payload *payload = &mgr->payloads[i];
3372                 bool put_port = false;
3373
3374                 /* solve the current payloads - compare to the hw ones
3375                    - update the hw view */
3376                 req_payload.start_slot = cur_slots;
3377                 if (vcpi) {
3378                         port = container_of(vcpi, struct drm_dp_mst_port,
3379                                             vcpi);
3380
3381                         mutex_lock(&mgr->lock);
3382                         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3383                         mutex_unlock(&mgr->lock);
3384
3385                         if (skip) {
3386                                 drm_dbg_kms(mgr->dev,
3387                                             "Virtual channel %d is not in current topology\n",
3388                                             i);
3389                                 continue;
3390                         }
3391                         /* Validated ports don't matter if we're releasing
3392                          * VCPI
3393                          */
3394                         if (vcpi->num_slots) {
3395                                 port = drm_dp_mst_topology_get_port_validated(
3396                                     mgr, port);
3397                                 if (!port) {
3398                                         if (vcpi->num_slots == payload->num_slots) {
3399                                                 cur_slots += vcpi->num_slots;
3400                                                 payload->start_slot = req_payload.start_slot;
3401                                                 continue;
3402                                         } else {
3403                                                 drm_dbg_kms(mgr->dev,
3404                                                             "Fail:set payload to invalid sink");
3405                                                 mutex_unlock(&mgr->payload_lock);
3406                                                 return -EINVAL;
3407                                         }
3408                                 }
3409                                 put_port = true;
3410                         }
3411
3412                         req_payload.num_slots = vcpi->num_slots;
3413                         req_payload.vcpi = vcpi->vcpi;
3414                 } else {
3415                         port = NULL;
3416                         req_payload.num_slots = 0;
3417                 }
3418
3419                 payload->start_slot = req_payload.start_slot;
3420                 /* work out what is required to happen with this payload */
3421                 if (payload->num_slots != req_payload.num_slots) {
3422
3423                         /* need to push an update for this payload */
3424                         if (req_payload.num_slots) {
3425                                 drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3426                                                             &req_payload);
3427                                 payload->num_slots = req_payload.num_slots;
3428                                 payload->vcpi = req_payload.vcpi;
3429
3430                         } else if (payload->num_slots) {
3431                                 payload->num_slots = 0;
3432                                 drm_dp_destroy_payload_step1(mgr, port,
3433                                                              payload->vcpi,
3434                                                              payload);
3435                                 req_payload.payload_state =
3436                                         payload->payload_state;
3437                                 payload->start_slot = 0;
3438                         }
3439                         payload->payload_state = req_payload.payload_state;
3440                 }
3441                 cur_slots += req_payload.num_slots;
3442
3443                 if (put_port)
3444                         drm_dp_mst_topology_put_port(port);
3445         }
3446
3447         for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3448                 if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3449                         i++;
3450                         continue;
3451                 }
3452
3453                 drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
3454                 for (j = i; j < mgr->max_payloads - 1; j++) {
3455                         mgr->payloads[j] = mgr->payloads[j + 1];
3456                         mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3457
3458                         if (mgr->proposed_vcpis[j] &&
3459                             mgr->proposed_vcpis[j]->num_slots) {
3460                                 set_bit(j + 1, &mgr->payload_mask);
3461                         } else {
3462                                 clear_bit(j + 1, &mgr->payload_mask);
3463                         }
3464                 }
3465
3466                 memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3467                        sizeof(struct drm_dp_payload));
3468                 mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3469                 clear_bit(mgr->max_payloads, &mgr->payload_mask);
3470         }
3471         mutex_unlock(&mgr->payload_lock);
3472
3473         return 0;
3474 }
3475 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3476
3477 /**
3478  * drm_dp_update_payload_part2() - Execute payload update part 2
3479  * @mgr: manager to use.
3480  *
3481  * This iterates over all proposed virtual channels, and tries to
3482  * allocate space in the link for them. For 0->slots transitions,
3483  * this step writes the remote VC payload commands. For slots->0
3484  * this just resets some internal state.
3485  */
3486 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3487 {
3488         struct drm_dp_mst_port *port;
3489         int i;
3490         int ret = 0;
3491         bool skip;
3492
3493         mutex_lock(&mgr->payload_lock);
3494         for (i = 0; i < mgr->max_payloads; i++) {
3495
3496                 if (!mgr->proposed_vcpis[i])
3497                         continue;
3498
3499                 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3500
3501                 mutex_lock(&mgr->lock);
3502                 skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3503                 mutex_unlock(&mgr->lock);
3504
3505                 if (skip)
3506                         continue;
3507
3508                 drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
3509                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3510                         ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3511                 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3512                         ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3513                 }
3514                 if (ret) {
3515                         mutex_unlock(&mgr->payload_lock);
3516                         return ret;
3517                 }
3518         }
3519         mutex_unlock(&mgr->payload_lock);
3520         return 0;
3521 }
3522 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3523
3524 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3525                                  struct drm_dp_mst_port *port,
3526                                  int offset, int size, u8 *bytes)
3527 {
3528         int ret = 0;
3529         struct drm_dp_sideband_msg_tx *txmsg;
3530         struct drm_dp_mst_branch *mstb;
3531
3532         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3533         if (!mstb)
3534                 return -EINVAL;
3535
3536         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3537         if (!txmsg) {
3538                 ret = -ENOMEM;
3539                 goto fail_put;
3540         }
3541
3542         build_dpcd_read(txmsg, port->port_num, offset, size);
3543         txmsg->dst = port->parent;
3544
3545         drm_dp_queue_down_tx(mgr, txmsg);
3546
3547         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3548         if (ret < 0)
3549                 goto fail_free;
3550
3551         if (txmsg->reply.reply_type == 1) {
3552                 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3553                             mstb, port->port_num, offset, size);
3554                 ret = -EIO;
3555                 goto fail_free;
3556         }
3557
3558         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3559                 ret = -EPROTO;
3560                 goto fail_free;
3561         }
3562
3563         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3564                     size);
3565         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3566
3567 fail_free:
3568         kfree(txmsg);
3569 fail_put:
3570         drm_dp_mst_topology_put_mstb(mstb);
3571
3572         return ret;
3573 }
3574
3575 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3576                                   struct drm_dp_mst_port *port,
3577                                   int offset, int size, u8 *bytes)
3578 {
3579         int ret;
3580         struct drm_dp_sideband_msg_tx *txmsg;
3581         struct drm_dp_mst_branch *mstb;
3582
3583         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3584         if (!mstb)
3585                 return -EINVAL;
3586
3587         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3588         if (!txmsg) {
3589                 ret = -ENOMEM;
3590                 goto fail_put;
3591         }
3592
3593         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3594         txmsg->dst = mstb;
3595
3596         drm_dp_queue_down_tx(mgr, txmsg);
3597
3598         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3599         if (ret > 0) {
3600                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3601                         ret = -EIO;
3602                 else
3603                         ret = size;
3604         }
3605
3606         kfree(txmsg);
3607 fail_put:
3608         drm_dp_mst_topology_put_mstb(mstb);
3609         return ret;
3610 }
3611
3612 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3613 {
3614         struct drm_dp_sideband_msg_reply_body reply;
3615
3616         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3617         reply.req_type = req_type;
3618         drm_dp_encode_sideband_reply(&reply, msg);
3619         return 0;
3620 }
3621
3622 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3623                                     struct drm_dp_mst_branch *mstb,
3624                                     int req_type, bool broadcast)
3625 {
3626         struct drm_dp_sideband_msg_tx *txmsg;
3627
3628         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3629         if (!txmsg)
3630                 return -ENOMEM;
3631
3632         txmsg->dst = mstb;
3633         drm_dp_encode_up_ack_reply(txmsg, req_type);
3634
3635         mutex_lock(&mgr->qlock);
3636         /* construct a chunk from the first msg in the tx_msg queue */
3637         process_single_tx_qlock(mgr, txmsg, true);
3638         mutex_unlock(&mgr->qlock);
3639
3640         kfree(txmsg);
3641         return 0;
3642 }
3643
3644 /**
3645  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3646  * @mgr: The &drm_dp_mst_topology_mgr to use
3647  * @link_rate: link rate in 10kbits/s units
3648  * @link_lane_count: lane count
3649  *
3650  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3651  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3652  * convert the number of PBNs required for a given stream to the number of
3653  * timeslots this stream requires in each MTP.
3654  */
3655 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3656                              int link_rate, int link_lane_count)
3657 {
3658         if (link_rate == 0 || link_lane_count == 0)
3659                 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3660                             link_rate, link_lane_count);
3661
3662         /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3663         return link_rate * link_lane_count / 54000;
3664 }
3665 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3666
3667 /**
3668  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3669  * @aux: The DP AUX channel to use
3670  * @dpcd: A cached copy of the DPCD capabilities for this sink
3671  *
3672  * Returns: %True if the sink supports MST, %false otherwise
3673  */
3674 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3675                          const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3676 {
3677         u8 mstm_cap;
3678
3679         if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3680                 return false;
3681
3682         if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3683                 return false;
3684
3685         return mstm_cap & DP_MST_CAP;
3686 }
3687 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3688
3689 /**
3690  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3691  * @mgr: manager to set state for
3692  * @mst_state: true to enable MST on this connector - false to disable.
3693  *
3694  * This is called by the driver when it detects an MST capable device plugged
3695  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3696  */
3697 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3698 {
3699         int ret = 0;
3700         struct drm_dp_mst_branch *mstb = NULL;
3701
3702         mutex_lock(&mgr->payload_lock);
3703         mutex_lock(&mgr->lock);
3704         if (mst_state == mgr->mst_state)
3705                 goto out_unlock;
3706
3707         mgr->mst_state = mst_state;
3708         /* set the device into MST mode */
3709         if (mst_state) {
3710                 struct drm_dp_payload reset_pay;
3711                 int lane_count;
3712                 int link_rate;
3713
3714                 WARN_ON(mgr->mst_primary);
3715
3716                 /* get dpcd info */
3717                 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3718                 if (ret < 0) {
3719                         drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3720                                     mgr->aux->name, ret);
3721                         goto out_unlock;
3722                 }
3723
3724                 lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
3725                 link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
3726                 mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
3727                                                         link_rate,
3728                                                         lane_count);
3729                 if (mgr->pbn_div == 0) {
3730                         ret = -EINVAL;
3731                         goto out_unlock;
3732                 }
3733
3734                 /* add initial branch device at LCT 1 */
3735                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3736                 if (mstb == NULL) {
3737                         ret = -ENOMEM;
3738                         goto out_unlock;
3739                 }
3740                 mstb->mgr = mgr;
3741
3742                 /* give this the main reference */
3743                 mgr->mst_primary = mstb;
3744                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3745
3746                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3747                                          DP_MST_EN |
3748                                          DP_UP_REQ_EN |
3749                                          DP_UPSTREAM_IS_SRC);
3750                 if (ret < 0)
3751                         goto out_unlock;
3752
3753                 reset_pay.start_slot = 0;
3754                 reset_pay.num_slots = 0x3f;
3755                 drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3756
3757                 queue_work(system_long_wq, &mgr->work);
3758
3759                 ret = 0;
3760         } else {
3761                 /* disable MST on the device */
3762                 mstb = mgr->mst_primary;
3763                 mgr->mst_primary = NULL;
3764                 /* this can fail if the device is gone */
3765                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3766                 ret = 0;
3767                 memset(mgr->payloads, 0,
3768                        mgr->max_payloads * sizeof(mgr->payloads[0]));
3769                 memset(mgr->proposed_vcpis, 0,
3770                        mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3771                 mgr->payload_mask = 0;
3772                 set_bit(0, &mgr->payload_mask);
3773                 mgr->vcpi_mask = 0;
3774                 mgr->payload_id_table_cleared = false;
3775         }
3776
3777 out_unlock:
3778         mutex_unlock(&mgr->lock);
3779         mutex_unlock(&mgr->payload_lock);
3780         if (mstb)
3781                 drm_dp_mst_topology_put_mstb(mstb);
3782         return ret;
3783
3784 }
3785 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3786
3787 static void
3788 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3789 {
3790         struct drm_dp_mst_port *port;
3791
3792         /* The link address will need to be re-sent on resume */
3793         mstb->link_address_sent = false;
3794
3795         list_for_each_entry(port, &mstb->ports, next)
3796                 if (port->mstb)
3797                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3798 }
3799
3800 /**
3801  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3802  * @mgr: manager to suspend
3803  *
3804  * This function tells the MST device that we can't handle UP messages
3805  * anymore. This should stop it from sending any since we are suspended.
3806  */
3807 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3808 {
3809         mutex_lock(&mgr->lock);
3810         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3811                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3812         mutex_unlock(&mgr->lock);
3813         flush_work(&mgr->up_req_work);
3814         flush_work(&mgr->work);
3815         flush_work(&mgr->delayed_destroy_work);
3816
3817         mutex_lock(&mgr->lock);
3818         if (mgr->mst_state && mgr->mst_primary)
3819                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3820         mutex_unlock(&mgr->lock);
3821 }
3822 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3823
3824 /**
3825  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3826  * @mgr: manager to resume
3827  * @sync: whether or not to perform topology reprobing synchronously
3828  *
3829  * This will fetch DPCD and see if the device is still there,
3830  * if it is, it will rewrite the MSTM control bits, and return.
3831  *
3832  * If the device fails this returns -1, and the driver should do
3833  * a full MST reprobe, in case we were undocked.
3834  *
3835  * During system resume (where it is assumed that the driver will be calling
3836  * drm_atomic_helper_resume()) this function should be called beforehand with
3837  * @sync set to true. In contexts like runtime resume where the driver is not
3838  * expected to be calling drm_atomic_helper_resume(), this function should be
3839  * called with @sync set to false in order to avoid deadlocking.
3840  *
3841  * Returns: -1 if the MST topology was removed while we were suspended, 0
3842  * otherwise.
3843  */
3844 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3845                                    bool sync)
3846 {
3847         int ret;
3848         u8 guid[16];
3849
3850         mutex_lock(&mgr->lock);
3851         if (!mgr->mst_primary)
3852                 goto out_fail;
3853
3854         if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3855                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3856                 goto out_fail;
3857         }
3858
3859         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3860                                  DP_MST_EN |
3861                                  DP_UP_REQ_EN |
3862                                  DP_UPSTREAM_IS_SRC);
3863         if (ret < 0) {
3864                 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3865                 goto out_fail;
3866         }
3867
3868         /* Some hubs forget their guids after they resume */
3869         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3870         if (ret != 16) {
3871                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3872                 goto out_fail;
3873         }
3874
3875         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3876         if (ret) {
3877                 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3878                 goto out_fail;
3879         }
3880
3881         /*
3882          * For the final step of resuming the topology, we need to bring the
3883          * state of our in-memory topology back into sync with reality. So,
3884          * restart the probing process as if we're probing a new hub
3885          */
3886         queue_work(system_long_wq, &mgr->work);
3887         mutex_unlock(&mgr->lock);
3888
3889         if (sync) {
3890                 drm_dbg_kms(mgr->dev,
3891                             "Waiting for link probe work to finish re-syncing topology...\n");
3892                 flush_work(&mgr->work);
3893         }
3894
3895         return 0;
3896
3897 out_fail:
3898         mutex_unlock(&mgr->lock);
3899         return -1;
3900 }
3901 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3902
3903 static bool
3904 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3905                       struct drm_dp_mst_branch **mstb)
3906 {
3907         int len;
3908         u8 replyblock[32];
3909         int replylen, curreply;
3910         int ret;
3911         u8 hdrlen;
3912         struct drm_dp_sideband_msg_hdr hdr;
3913         struct drm_dp_sideband_msg_rx *msg =
3914                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3915         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3916                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3917
3918         if (!up)
3919                 *mstb = NULL;
3920
3921         len = min(mgr->max_dpcd_transaction_bytes, 16);
3922         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3923         if (ret != len) {
3924                 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3925                 return false;
3926         }
3927
3928         ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3929         if (ret == false) {
3930                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3931                                1, replyblock, len, false);
3932                 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3933                 return false;
3934         }
3935
3936         if (!up) {
3937                 /* Caller is responsible for giving back this reference */
3938                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3939                 if (!*mstb) {
3940                         drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3941                         return false;
3942                 }
3943         }
3944
3945         if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3946                 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3947                 return false;
3948         }
3949
3950         replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3951         ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3952         if (!ret) {
3953                 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3954                 return false;
3955         }
3956
3957         replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3958         curreply = len;
3959         while (replylen > 0) {
3960                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3961                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3962                                     replyblock, len);
3963                 if (ret != len) {
3964                         drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3965                                     len, ret);
3966                         return false;
3967                 }
3968
3969                 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3970                 if (!ret) {
3971                         drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3972                         return false;
3973                 }
3974
3975                 curreply += len;
3976                 replylen -= len;
3977         }
3978         return true;
3979 }
3980
3981 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3982 {
3983         struct drm_dp_sideband_msg_tx *txmsg;
3984         struct drm_dp_mst_branch *mstb = NULL;
3985         struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3986
3987         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3988                 goto out;
3989
3990         /* Multi-packet message transmission, don't clear the reply */
3991         if (!msg->have_eomt)
3992                 goto out;
3993
3994         /* find the message */
3995         mutex_lock(&mgr->qlock);
3996         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3997                                          struct drm_dp_sideband_msg_tx, next);
3998         mutex_unlock(&mgr->qlock);
3999
4000         /* Were we actually expecting a response, and from this mstb? */
4001         if (!txmsg || txmsg->dst != mstb) {
4002                 struct drm_dp_sideband_msg_hdr *hdr;
4003
4004                 hdr = &msg->initial_hdr;
4005                 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
4006                             mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
4007                 goto out_clear_reply;
4008         }
4009
4010         drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
4011
4012         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4013                 drm_dbg_kms(mgr->dev,
4014                             "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
4015                             txmsg->reply.req_type,
4016                             drm_dp_mst_req_type_str(txmsg->reply.req_type),
4017                             txmsg->reply.u.nak.reason,
4018                             drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
4019                             txmsg->reply.u.nak.nak_data);
4020         }
4021
4022         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4023         drm_dp_mst_topology_put_mstb(mstb);
4024
4025         mutex_lock(&mgr->qlock);
4026         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
4027         list_del(&txmsg->next);
4028         mutex_unlock(&mgr->qlock);
4029
4030         wake_up_all(&mgr->tx_waitq);
4031
4032         return 0;
4033
4034 out_clear_reply:
4035         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4036 out:
4037         if (mstb)
4038                 drm_dp_mst_topology_put_mstb(mstb);
4039
4040         return 0;
4041 }
4042
4043 static inline bool
4044 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4045                           struct drm_dp_pending_up_req *up_req)
4046 {
4047         struct drm_dp_mst_branch *mstb = NULL;
4048         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4049         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4050         bool hotplug = false;
4051
4052         if (hdr->broadcast) {
4053                 const u8 *guid = NULL;
4054
4055                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4056                         guid = msg->u.conn_stat.guid;
4057                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4058                         guid = msg->u.resource_stat.guid;
4059
4060                 if (guid)
4061                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4062         } else {
4063                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4064         }
4065
4066         if (!mstb) {
4067                 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
4068                 return false;
4069         }
4070
4071         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4072         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4073                 drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4074                 hotplug = true;
4075         }
4076
4077         drm_dp_mst_topology_put_mstb(mstb);
4078         return hotplug;
4079 }
4080
4081 static void drm_dp_mst_up_req_work(struct work_struct *work)
4082 {
4083         struct drm_dp_mst_topology_mgr *mgr =
4084                 container_of(work, struct drm_dp_mst_topology_mgr,
4085                              up_req_work);
4086         struct drm_dp_pending_up_req *up_req;
4087         bool send_hotplug = false;
4088
4089         mutex_lock(&mgr->probe_lock);
4090         while (true) {
4091                 mutex_lock(&mgr->up_req_lock);
4092                 up_req = list_first_entry_or_null(&mgr->up_req_list,
4093                                                   struct drm_dp_pending_up_req,
4094                                                   next);
4095                 if (up_req)
4096                         list_del(&up_req->next);
4097                 mutex_unlock(&mgr->up_req_lock);
4098
4099                 if (!up_req)
4100                         break;
4101
4102                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4103                 kfree(up_req);
4104         }
4105         mutex_unlock(&mgr->probe_lock);
4106
4107         if (send_hotplug)
4108                 drm_kms_helper_hotplug_event(mgr->dev);
4109 }
4110
4111 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4112 {
4113         struct drm_dp_pending_up_req *up_req;
4114
4115         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4116                 goto out;
4117
4118         if (!mgr->up_req_recv.have_eomt)
4119                 return 0;
4120
4121         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4122         if (!up_req)
4123                 return -ENOMEM;
4124
4125         INIT_LIST_HEAD(&up_req->next);
4126
4127         drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4128
4129         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4130             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4131                 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4132                             up_req->msg.req_type);
4133                 kfree(up_req);
4134                 goto out;
4135         }
4136
4137         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4138                                  false);
4139
4140         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4141                 const struct drm_dp_connection_status_notify *conn_stat =
4142                         &up_req->msg.u.conn_stat;
4143
4144                 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4145                             conn_stat->port_number,
4146                             conn_stat->legacy_device_plug_status,
4147                             conn_stat->displayport_device_plug_status,
4148                             conn_stat->message_capability_status,
4149                             conn_stat->input_port,
4150                             conn_stat->peer_device_type);
4151         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4152                 const struct drm_dp_resource_status_notify *res_stat =
4153                         &up_req->msg.u.resource_stat;
4154
4155                 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4156                             res_stat->port_number,
4157                             res_stat->available_pbn);
4158         }
4159
4160         up_req->hdr = mgr->up_req_recv.initial_hdr;
4161         mutex_lock(&mgr->up_req_lock);
4162         list_add_tail(&up_req->next, &mgr->up_req_list);
4163         mutex_unlock(&mgr->up_req_lock);
4164         queue_work(system_long_wq, &mgr->up_req_work);
4165
4166 out:
4167         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4168         return 0;
4169 }
4170
4171 /**
4172  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4173  * @mgr: manager to notify irq for.
4174  * @esi: 4 bytes from SINK_COUNT_ESI
4175  * @handled: whether the hpd interrupt was consumed or not
4176  *
4177  * This should be called from the driver when it detects a short IRQ,
4178  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4179  * topology manager will process the sideband messages received as a result
4180  * of this.
4181  */
4182 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4183 {
4184         int ret = 0;
4185         int sc;
4186         *handled = false;
4187         sc = DP_GET_SINK_COUNT(esi[0]);
4188
4189         if (sc != mgr->sink_count) {
4190                 mgr->sink_count = sc;
4191                 *handled = true;
4192         }
4193
4194         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4195                 ret = drm_dp_mst_handle_down_rep(mgr);
4196                 *handled = true;
4197         }
4198
4199         if (esi[1] & DP_UP_REQ_MSG_RDY) {
4200                 ret |= drm_dp_mst_handle_up_req(mgr);
4201                 *handled = true;
4202         }
4203
4204         drm_dp_mst_kick_tx(mgr);
4205         return ret;
4206 }
4207 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4208
4209 /**
4210  * drm_dp_mst_detect_port() - get connection status for an MST port
4211  * @connector: DRM connector for this port
4212  * @ctx: The acquisition context to use for grabbing locks
4213  * @mgr: manager for this port
4214  * @port: pointer to a port
4215  *
4216  * This returns the current connection state for a port.
4217  */
4218 int
4219 drm_dp_mst_detect_port(struct drm_connector *connector,
4220                        struct drm_modeset_acquire_ctx *ctx,
4221                        struct drm_dp_mst_topology_mgr *mgr,
4222                        struct drm_dp_mst_port *port)
4223 {
4224         int ret;
4225
4226         /* we need to search for the port in the mgr in case it's gone */
4227         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4228         if (!port)
4229                 return connector_status_disconnected;
4230
4231         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4232         if (ret)
4233                 goto out;
4234
4235         ret = connector_status_disconnected;
4236
4237         if (!port->ddps)
4238                 goto out;
4239
4240         switch (port->pdt) {
4241         case DP_PEER_DEVICE_NONE:
4242                 break;
4243         case DP_PEER_DEVICE_MST_BRANCHING:
4244                 if (!port->mcs)
4245                         ret = connector_status_connected;
4246                 break;
4247
4248         case DP_PEER_DEVICE_SST_SINK:
4249                 ret = connector_status_connected;
4250                 /* for logical ports - cache the EDID */
4251                 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4252                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4253                 break;
4254         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4255                 if (port->ldps)
4256                         ret = connector_status_connected;
4257                 break;
4258         }
4259 out:
4260         drm_dp_mst_topology_put_port(port);
4261         return ret;
4262 }
4263 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4264
4265 /**
4266  * drm_dp_mst_get_edid() - get EDID for an MST port
4267  * @connector: toplevel connector to get EDID for
4268  * @mgr: manager for this port
4269  * @port: unverified pointer to a port.
4270  *
4271  * This returns an EDID for the port connected to a connector,
4272  * It validates the pointer still exists so the caller doesn't require a
4273  * reference.
4274  */
4275 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4276 {
4277         struct edid *edid = NULL;
4278
4279         /* we need to search for the port in the mgr in case it's gone */
4280         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4281         if (!port)
4282                 return NULL;
4283
4284         if (port->cached_edid)
4285                 edid = drm_edid_duplicate(port->cached_edid);
4286         else {
4287                 edid = drm_get_edid(connector, &port->aux.ddc);
4288         }
4289         port->has_audio = drm_detect_monitor_audio(edid);
4290         drm_dp_mst_topology_put_port(port);
4291         return edid;
4292 }
4293 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4294
4295 /**
4296  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4297  * @mgr: manager to use
4298  * @pbn: payload bandwidth to convert into slots.
4299  *
4300  * Calculate the number of VCPI slots that will be required for the given PBN
4301  * value. This function is deprecated, and should not be used in atomic
4302  * drivers.
4303  *
4304  * RETURNS:
4305  * The total slots required for this port, or error.
4306  */
4307 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4308                            int pbn)
4309 {
4310         int num_slots;
4311
4312         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4313
4314         /* max. time slots - one slot for MTP header */
4315         if (num_slots > 63)
4316                 return -ENOSPC;
4317         return num_slots;
4318 }
4319 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4320
4321 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4322                             struct drm_dp_vcpi *vcpi, int pbn, int slots)
4323 {
4324         int ret;
4325
4326         vcpi->pbn = pbn;
4327         vcpi->aligned_pbn = slots * mgr->pbn_div;
4328         vcpi->num_slots = slots;
4329
4330         ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4331         if (ret < 0)
4332                 return ret;
4333         return 0;
4334 }
4335
4336 /**
4337  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4338  * @state: global atomic state
4339  * @mgr: MST topology manager for the port
4340  * @port: port to find vcpi slots for
4341  * @pbn: bandwidth required for the mode in PBN
4342  * @pbn_div: divider for DSC mode that takes FEC into account
4343  *
4344  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4345  * may have had. Any atomic drivers which support MST must call this function
4346  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4347  * current VCPI allocation for the new state, but only when
4348  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4349  * to ensure compatibility with userspace applications that still use the
4350  * legacy modesetting UAPI.
4351  *
4352  * Allocations set by this function are not checked against the bandwidth
4353  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4354  *
4355  * Additionally, it is OK to call this function multiple times on the same
4356  * @port as needed. It is not OK however, to call this function and
4357  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4358  *
4359  * See also:
4360  * drm_dp_atomic_release_vcpi_slots()
4361  * drm_dp_mst_atomic_check()
4362  *
4363  * Returns:
4364  * Total slots in the atomic state assigned for this port, or a negative error
4365  * code if the port no longer exists
4366  */
4367 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4368                                   struct drm_dp_mst_topology_mgr *mgr,
4369                                   struct drm_dp_mst_port *port, int pbn,
4370                                   int pbn_div)
4371 {
4372         struct drm_dp_mst_topology_state *topology_state;
4373         struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4374         int prev_slots, prev_bw, req_slots;
4375
4376         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4377         if (IS_ERR(topology_state))
4378                 return PTR_ERR(topology_state);
4379
4380         /* Find the current allocation for this port, if any */
4381         list_for_each_entry(pos, &topology_state->vcpis, next) {
4382                 if (pos->port == port) {
4383                         vcpi = pos;
4384                         prev_slots = vcpi->vcpi;
4385                         prev_bw = vcpi->pbn;
4386
4387                         /*
4388                          * This should never happen, unless the driver tries
4389                          * releasing and allocating the same VCPI allocation,
4390                          * which is an error
4391                          */
4392                         if (WARN_ON(!prev_slots)) {
4393                                 drm_err(mgr->dev,
4394                                         "cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4395                                         port);
4396                                 return -EINVAL;
4397                         }
4398
4399                         break;
4400                 }
4401         }
4402         if (!vcpi) {
4403                 prev_slots = 0;
4404                 prev_bw = 0;
4405         }
4406
4407         if (pbn_div <= 0)
4408                 pbn_div = mgr->pbn_div;
4409
4410         req_slots = DIV_ROUND_UP(pbn, pbn_div);
4411
4412         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4413                        port->connector->base.id, port->connector->name,
4414                        port, prev_slots, req_slots);
4415         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4416                        port->connector->base.id, port->connector->name,
4417                        port, prev_bw, pbn);
4418
4419         /* Add the new allocation to the state */
4420         if (!vcpi) {
4421                 vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4422                 if (!vcpi)
4423                         return -ENOMEM;
4424
4425                 drm_dp_mst_get_port_malloc(port);
4426                 vcpi->port = port;
4427                 list_add(&vcpi->next, &topology_state->vcpis);
4428         }
4429         vcpi->vcpi = req_slots;
4430         vcpi->pbn = pbn;
4431
4432         return req_slots;
4433 }
4434 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4435
4436 /**
4437  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4438  * @state: global atomic state
4439  * @mgr: MST topology manager for the port
4440  * @port: The port to release the VCPI slots from
4441  *
4442  * Releases any VCPI slots that have been allocated to a port in the atomic
4443  * state. Any atomic drivers which support MST must call this function in
4444  * their &drm_connector_helper_funcs.atomic_check() callback when the
4445  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4446  * removed) when it had VCPI allocated in the previous atomic state.
4447  *
4448  * It is OK to call this even if @port has been removed from the system.
4449  * Additionally, it is OK to call this function multiple times on the same
4450  * @port as needed. It is not OK however, to call this function and
4451  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4452  * phase.
4453  *
4454  * See also:
4455  * drm_dp_atomic_find_vcpi_slots()
4456  * drm_dp_mst_atomic_check()
4457  *
4458  * Returns:
4459  * 0 if all slots for this port were added back to
4460  * &drm_dp_mst_topology_state.avail_slots or negative error code
4461  */
4462 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4463                                      struct drm_dp_mst_topology_mgr *mgr,
4464                                      struct drm_dp_mst_port *port)
4465 {
4466         struct drm_dp_mst_topology_state *topology_state;
4467         struct drm_dp_vcpi_allocation *pos;
4468         bool found = false;
4469
4470         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4471         if (IS_ERR(topology_state))
4472                 return PTR_ERR(topology_state);
4473
4474         list_for_each_entry(pos, &topology_state->vcpis, next) {
4475                 if (pos->port == port) {
4476                         found = true;
4477                         break;
4478                 }
4479         }
4480         if (WARN_ON(!found)) {
4481                 drm_err(mgr->dev, "no VCPI for [MST PORT:%p] found in mst state %p\n",
4482                         port, &topology_state->base);
4483                 return -EINVAL;
4484         }
4485
4486         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4487         if (pos->vcpi) {
4488                 drm_dp_mst_put_port_malloc(port);
4489                 pos->vcpi = 0;
4490                 pos->pbn = 0;
4491         }
4492
4493         return 0;
4494 }
4495 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4496
4497 /**
4498  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4499  * @mst_state: mst_state to update
4500  * @link_encoding_cap: the ecoding format on the link
4501  */
4502 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4503 {
4504         if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4505                 mst_state->total_avail_slots = 64;
4506                 mst_state->start_slot = 0;
4507         } else {
4508                 mst_state->total_avail_slots = 63;
4509                 mst_state->start_slot = 1;
4510         }
4511
4512         DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4513                       (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4514                       mst_state);
4515 }
4516 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4517
4518 /**
4519  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4520  * @mgr: manager for this port
4521  * @port: port to allocate a virtual channel for.
4522  * @pbn: payload bandwidth number to request
4523  * @slots: returned number of slots for this PBN.
4524  */
4525 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4526                               struct drm_dp_mst_port *port, int pbn, int slots)
4527 {
4528         int ret;
4529
4530         if (slots < 0)
4531                 return false;
4532
4533         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4534         if (!port)
4535                 return false;
4536
4537         if (port->vcpi.vcpi > 0) {
4538                 drm_dbg_kms(mgr->dev,
4539                             "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4540                             port->vcpi.vcpi, port->vcpi.pbn, pbn);
4541                 if (pbn == port->vcpi.pbn) {
4542                         drm_dp_mst_topology_put_port(port);
4543                         return true;
4544                 }
4545         }
4546
4547         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4548         if (ret) {
4549                 drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d ret=%d\n",
4550                             DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4551                 drm_dp_mst_topology_put_port(port);
4552                 goto out;
4553         }
4554         drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
4555
4556         /* Keep port allocated until its payload has been removed */
4557         drm_dp_mst_get_port_malloc(port);
4558         drm_dp_mst_topology_put_port(port);
4559         return true;
4560 out:
4561         return false;
4562 }
4563 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4564
4565 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4566 {
4567         int slots = 0;
4568
4569         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4570         if (!port)
4571                 return slots;
4572
4573         slots = port->vcpi.num_slots;
4574         drm_dp_mst_topology_put_port(port);
4575         return slots;
4576 }
4577 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4578
4579 /**
4580  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4581  * @mgr: manager for this port
4582  * @port: unverified pointer to a port.
4583  *
4584  * This just resets the number of slots for the ports VCPI for later programming.
4585  */
4586 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4587 {
4588         /*
4589          * A port with VCPI will remain allocated until its VCPI is
4590          * released, no verified ref needed
4591          */
4592
4593         port->vcpi.num_slots = 0;
4594 }
4595 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4596
4597 /**
4598  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4599  * @mgr: manager for this port
4600  * @port: port to deallocate vcpi for
4601  *
4602  * This can be called unconditionally, regardless of whether
4603  * drm_dp_mst_allocate_vcpi() succeeded or not.
4604  */
4605 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4606                                 struct drm_dp_mst_port *port)
4607 {
4608         bool skip;
4609
4610         if (!port->vcpi.vcpi)
4611                 return;
4612
4613         mutex_lock(&mgr->lock);
4614         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
4615         mutex_unlock(&mgr->lock);
4616
4617         if (skip)
4618                 return;
4619
4620         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4621         port->vcpi.num_slots = 0;
4622         port->vcpi.pbn = 0;
4623         port->vcpi.aligned_pbn = 0;
4624         port->vcpi.vcpi = 0;
4625         drm_dp_mst_put_port_malloc(port);
4626 }
4627 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4628
4629 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4630                                      int id, struct drm_dp_payload *payload)
4631 {
4632         u8 payload_alloc[3], status;
4633         int ret;
4634         int retries = 0;
4635
4636         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4637                            DP_PAYLOAD_TABLE_UPDATED);
4638
4639         payload_alloc[0] = id;
4640         payload_alloc[1] = payload->start_slot;
4641         payload_alloc[2] = payload->num_slots;
4642
4643         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4644         if (ret != 3) {
4645                 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4646                 goto fail;
4647         }
4648
4649 retry:
4650         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4651         if (ret < 0) {
4652                 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4653                 goto fail;
4654         }
4655
4656         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4657                 retries++;
4658                 if (retries < 20) {
4659                         usleep_range(10000, 20000);
4660                         goto retry;
4661                 }
4662                 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4663                             status);
4664                 ret = -EINVAL;
4665                 goto fail;
4666         }
4667         ret = 0;
4668 fail:
4669         return ret;
4670 }
4671
4672 static int do_get_act_status(struct drm_dp_aux *aux)
4673 {
4674         int ret;
4675         u8 status;
4676
4677         ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4678         if (ret < 0)
4679                 return ret;
4680
4681         return status;
4682 }
4683
4684 /**
4685  * drm_dp_check_act_status() - Polls for ACT handled status.
4686  * @mgr: manager to use
4687  *
4688  * Tries waiting for the MST hub to finish updating it's payload table by
4689  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4690  * take that long).
4691  *
4692  * Returns:
4693  * 0 if the ACT was handled in time, negative error code on failure.
4694  */
4695 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4696 {
4697         /*
4698          * There doesn't seem to be any recommended retry count or timeout in
4699          * the MST specification. Since some hubs have been observed to take
4700          * over 1 second to update their payload allocations under certain
4701          * conditions, we use a rather large timeout value.
4702          */
4703         const int timeout_ms = 3000;
4704         int ret, status;
4705
4706         ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4707                                  status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4708                                  200, timeout_ms * USEC_PER_MSEC);
4709         if (ret < 0 && status >= 0) {
4710                 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4711                         timeout_ms, status);
4712                 return -EINVAL;
4713         } else if (status < 0) {
4714                 /*
4715                  * Failure here isn't unexpected - the hub may have
4716                  * just been unplugged
4717                  */
4718                 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4719                 return status;
4720         }
4721
4722         return 0;
4723 }
4724 EXPORT_SYMBOL(drm_dp_check_act_status);
4725
4726 /**
4727  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4728  * @clock: dot clock for the mode
4729  * @bpp: bpp for the mode.
4730  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4731  *
4732  * This uses the formula in the spec to calculate the PBN value for a mode.
4733  */
4734 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4735 {
4736         /*
4737          * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4738          * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4739          * common multiplier to render an integer PBN for all link rate/lane
4740          * counts combinations
4741          * calculate
4742          * peak_kbps *= (1006/1000)
4743          * peak_kbps *= (64/54)
4744          * peak_kbps *= 8    convert to bytes
4745          *
4746          * If the bpp is in units of 1/16, further divide by 16. Put this
4747          * factor in the numerator rather than the denominator to avoid
4748          * integer overflow
4749          */
4750
4751         if (dsc)
4752                 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4753                                         8 * 54 * 1000 * 1000);
4754
4755         return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4756                                 8 * 54 * 1000 * 1000);
4757 }
4758 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4759
4760 /* we want to kick the TX after we've ack the up/down IRQs. */
4761 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4762 {
4763         queue_work(system_long_wq, &mgr->tx_work);
4764 }
4765
4766 /*
4767  * Helper function for parsing DP device types into convenient strings
4768  * for use with dp_mst_topology
4769  */
4770 static const char *pdt_to_string(u8 pdt)
4771 {
4772         switch (pdt) {
4773         case DP_PEER_DEVICE_NONE:
4774                 return "NONE";
4775         case DP_PEER_DEVICE_SOURCE_OR_SST:
4776                 return "SOURCE OR SST";
4777         case DP_PEER_DEVICE_MST_BRANCHING:
4778                 return "MST BRANCHING";
4779         case DP_PEER_DEVICE_SST_SINK:
4780                 return "SST SINK";
4781         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4782                 return "DP LEGACY CONV";
4783         default:
4784                 return "ERR";
4785         }
4786 }
4787
4788 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4789                                  struct drm_dp_mst_branch *mstb)
4790 {
4791         struct drm_dp_mst_port *port;
4792         int tabs = mstb->lct;
4793         char prefix[10];
4794         int i;
4795
4796         for (i = 0; i < tabs; i++)
4797                 prefix[i] = '\t';
4798         prefix[i] = '\0';
4799
4800         seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4801         list_for_each_entry(port, &mstb->ports, next) {
4802                 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4803                            prefix,
4804                            port->port_num,
4805                            port,
4806                            port->input ? "input" : "output",
4807                            pdt_to_string(port->pdt),
4808                            port->ddps,
4809                            port->ldps,
4810                            port->num_sdp_streams,
4811                            port->num_sdp_stream_sinks,
4812                            port->fec_capable ? "true" : "false",
4813                            port->connector);
4814                 if (port->mstb)
4815                         drm_dp_mst_dump_mstb(m, port->mstb);
4816         }
4817 }
4818
4819 #define DP_PAYLOAD_TABLE_SIZE           64
4820
4821 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4822                                   char *buf)
4823 {
4824         int i;
4825
4826         for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4827                 if (drm_dp_dpcd_read(mgr->aux,
4828                                      DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4829                                      &buf[i], 16) != 16)
4830                         return false;
4831         }
4832         return true;
4833 }
4834
4835 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4836                                struct drm_dp_mst_port *port, char *name,
4837                                int namelen)
4838 {
4839         struct edid *mst_edid;
4840
4841         mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4842         drm_edid_get_monitor_name(mst_edid, name, namelen);
4843         kfree(mst_edid);
4844 }
4845
4846 /**
4847  * drm_dp_mst_dump_topology(): dump topology to seq file.
4848  * @m: seq_file to dump output to
4849  * @mgr: manager to dump current topology for.
4850  *
4851  * helper to dump MST topology to a seq file for debugfs.
4852  */
4853 void drm_dp_mst_dump_topology(struct seq_file *m,
4854                               struct drm_dp_mst_topology_mgr *mgr)
4855 {
4856         int i;
4857         struct drm_dp_mst_port *port;
4858
4859         mutex_lock(&mgr->lock);
4860         if (mgr->mst_primary)
4861                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4862
4863         /* dump VCPIs */
4864         mutex_unlock(&mgr->lock);
4865
4866         mutex_lock(&mgr->payload_lock);
4867         seq_printf(m, "\n*** VCPI Info ***\n");
4868         seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
4869
4870         seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
4871         for (i = 0; i < mgr->max_payloads; i++) {
4872                 if (mgr->proposed_vcpis[i]) {
4873                         char name[14];
4874
4875                         port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4876                         fetch_monitor_name(mgr, port, name, sizeof(name));
4877                         seq_printf(m, "%10d%10d%10d%10d%20s\n",
4878                                    i,
4879                                    port->port_num,
4880                                    port->vcpi.vcpi,
4881                                    port->vcpi.num_slots,
4882                                    (*name != 0) ? name : "Unknown");
4883                 } else
4884                         seq_printf(m, "%6d - Unused\n", i);
4885         }
4886         seq_printf(m, "\n*** Payload Info ***\n");
4887         seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
4888         for (i = 0; i < mgr->max_payloads; i++) {
4889                 seq_printf(m, "%10d%10d%15d%10d\n",
4890                            i,
4891                            mgr->payloads[i].payload_state,
4892                            mgr->payloads[i].start_slot,
4893                            mgr->payloads[i].num_slots);
4894         }
4895         mutex_unlock(&mgr->payload_lock);
4896
4897         seq_printf(m, "\n*** DPCD Info ***\n");
4898         mutex_lock(&mgr->lock);
4899         if (mgr->mst_primary) {
4900                 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4901                 int ret;
4902
4903                 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4904                         seq_printf(m, "dpcd read failed\n");
4905                         goto out;
4906                 }
4907                 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4908
4909                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4910                 if (ret) {
4911                         seq_printf(m, "faux/mst read failed\n");
4912                         goto out;
4913                 }
4914                 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4915
4916                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4917                 if (ret) {
4918                         seq_printf(m, "mst ctrl read failed\n");
4919                         goto out;
4920                 }
4921                 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4922
4923                 /* dump the standard OUI branch header */
4924                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4925                 if (ret) {
4926                         seq_printf(m, "branch oui read failed\n");
4927                         goto out;
4928                 }
4929                 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4930
4931                 for (i = 0x3; i < 0x8 && buf[i]; i++)
4932                         seq_printf(m, "%c", buf[i]);
4933                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4934                            buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4935                 if (dump_dp_payload_table(mgr, buf))
4936                         seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4937         }
4938
4939 out:
4940         mutex_unlock(&mgr->lock);
4941
4942 }
4943 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4944
4945 static void drm_dp_tx_work(struct work_struct *work)
4946 {
4947         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4948
4949         mutex_lock(&mgr->qlock);
4950         if (!list_empty(&mgr->tx_msg_downq))
4951                 process_single_down_tx_qlock(mgr);
4952         mutex_unlock(&mgr->qlock);
4953 }
4954
4955 static inline void
4956 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4957 {
4958         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4959
4960         if (port->connector) {
4961                 drm_connector_unregister(port->connector);
4962                 drm_connector_put(port->connector);
4963         }
4964
4965         drm_dp_mst_put_port_malloc(port);
4966 }
4967
4968 static inline void
4969 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4970 {
4971         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4972         struct drm_dp_mst_port *port, *port_tmp;
4973         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4974         bool wake_tx = false;
4975
4976         mutex_lock(&mgr->lock);
4977         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4978                 list_del(&port->next);
4979                 drm_dp_mst_topology_put_port(port);
4980         }
4981         mutex_unlock(&mgr->lock);
4982
4983         /* drop any tx slot msg */
4984         mutex_lock(&mstb->mgr->qlock);
4985         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4986                 if (txmsg->dst != mstb)
4987                         continue;
4988
4989                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4990                 list_del(&txmsg->next);
4991                 wake_tx = true;
4992         }
4993         mutex_unlock(&mstb->mgr->qlock);
4994
4995         if (wake_tx)
4996                 wake_up_all(&mstb->mgr->tx_waitq);
4997
4998         drm_dp_mst_put_mstb_malloc(mstb);
4999 }
5000
5001 static void drm_dp_delayed_destroy_work(struct work_struct *work)
5002 {
5003         struct drm_dp_mst_topology_mgr *mgr =
5004                 container_of(work, struct drm_dp_mst_topology_mgr,
5005                              delayed_destroy_work);
5006         bool send_hotplug = false, go_again;
5007
5008         /*
5009          * Not a regular list traverse as we have to drop the destroy
5010          * connector lock before destroying the mstb/port, to avoid AB->BA
5011          * ordering between this lock and the config mutex.
5012          */
5013         do {
5014                 go_again = false;
5015
5016                 for (;;) {
5017                         struct drm_dp_mst_branch *mstb;
5018
5019                         mutex_lock(&mgr->delayed_destroy_lock);
5020                         mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5021                                                         struct drm_dp_mst_branch,
5022                                                         destroy_next);
5023                         if (mstb)
5024                                 list_del(&mstb->destroy_next);
5025                         mutex_unlock(&mgr->delayed_destroy_lock);
5026
5027                         if (!mstb)
5028                                 break;
5029
5030                         drm_dp_delayed_destroy_mstb(mstb);
5031                         go_again = true;
5032                 }
5033
5034                 for (;;) {
5035                         struct drm_dp_mst_port *port;
5036
5037                         mutex_lock(&mgr->delayed_destroy_lock);
5038                         port = list_first_entry_or_null(&mgr->destroy_port_list,
5039                                                         struct drm_dp_mst_port,
5040                                                         next);
5041                         if (port)
5042                                 list_del(&port->next);
5043                         mutex_unlock(&mgr->delayed_destroy_lock);
5044
5045                         if (!port)
5046                                 break;
5047
5048                         drm_dp_delayed_destroy_port(port);
5049                         send_hotplug = true;
5050                         go_again = true;
5051                 }
5052         } while (go_again);
5053
5054         if (send_hotplug)
5055                 drm_kms_helper_hotplug_event(mgr->dev);
5056 }
5057
5058 static struct drm_private_state *
5059 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5060 {
5061         struct drm_dp_mst_topology_state *state, *old_state =
5062                 to_dp_mst_topology_state(obj->state);
5063         struct drm_dp_vcpi_allocation *pos, *vcpi;
5064
5065         state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5066         if (!state)
5067                 return NULL;
5068
5069         __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5070
5071         INIT_LIST_HEAD(&state->vcpis);
5072
5073         list_for_each_entry(pos, &old_state->vcpis, next) {
5074                 /* Prune leftover freed VCPI allocations */
5075                 if (!pos->vcpi)
5076                         continue;
5077
5078                 vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
5079                 if (!vcpi)
5080                         goto fail;
5081
5082                 drm_dp_mst_get_port_malloc(vcpi->port);
5083                 list_add(&vcpi->next, &state->vcpis);
5084         }
5085
5086         return &state->base;
5087
5088 fail:
5089         list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
5090                 drm_dp_mst_put_port_malloc(pos->port);
5091                 kfree(pos);
5092         }
5093         kfree(state);
5094
5095         return NULL;
5096 }
5097
5098 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5099                                      struct drm_private_state *state)
5100 {
5101         struct drm_dp_mst_topology_state *mst_state =
5102                 to_dp_mst_topology_state(state);
5103         struct drm_dp_vcpi_allocation *pos, *tmp;
5104
5105         list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5106                 /* We only keep references to ports with non-zero VCPIs */
5107                 if (pos->vcpi)
5108                         drm_dp_mst_put_port_malloc(pos->port);
5109                 kfree(pos);
5110         }
5111
5112         kfree(mst_state);
5113 }
5114
5115 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5116                                                  struct drm_dp_mst_branch *branch)
5117 {
5118         while (port->parent) {
5119                 if (port->parent == branch)
5120                         return true;
5121
5122                 if (port->parent->port_parent)
5123                         port = port->parent->port_parent;
5124                 else
5125                         break;
5126         }
5127         return false;
5128 }
5129
5130 static int
5131 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5132                                       struct drm_dp_mst_topology_state *state);
5133
5134 static int
5135 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5136                                       struct drm_dp_mst_topology_state *state)
5137 {
5138         struct drm_dp_vcpi_allocation *vcpi;
5139         struct drm_dp_mst_port *port;
5140         int pbn_used = 0, ret;
5141         bool found = false;
5142
5143         /* Check that we have at least one port in our state that's downstream
5144          * of this branch, otherwise we can skip this branch
5145          */
5146         list_for_each_entry(vcpi, &state->vcpis, next) {
5147                 if (!vcpi->pbn ||
5148                     !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5149                         continue;
5150
5151                 found = true;
5152                 break;
5153         }
5154         if (!found)
5155                 return 0;
5156
5157         if (mstb->port_parent)
5158                 drm_dbg_atomic(mstb->mgr->dev,
5159                                "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5160                                mstb->port_parent->parent, mstb->port_parent, mstb);
5161         else
5162                 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5163
5164         list_for_each_entry(port, &mstb->ports, next) {
5165                 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5166                 if (ret < 0)
5167                         return ret;
5168
5169                 pbn_used += ret;
5170         }
5171
5172         return pbn_used;
5173 }
5174
5175 static int
5176 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5177                                       struct drm_dp_mst_topology_state *state)
5178 {
5179         struct drm_dp_vcpi_allocation *vcpi;
5180         int pbn_used = 0;
5181
5182         if (port->pdt == DP_PEER_DEVICE_NONE)
5183                 return 0;
5184
5185         if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5186                 bool found = false;
5187
5188                 list_for_each_entry(vcpi, &state->vcpis, next) {
5189                         if (vcpi->port != port)
5190                                 continue;
5191                         if (!vcpi->pbn)
5192                                 return 0;
5193
5194                         found = true;
5195                         break;
5196                 }
5197                 if (!found)
5198                         return 0;
5199
5200                 /*
5201                  * This could happen if the sink deasserted its HPD line, but
5202                  * the branch device still reports it as attached (PDT != NONE).
5203                  */
5204                 if (!port->full_pbn) {
5205                         drm_dbg_atomic(port->mgr->dev,
5206                                        "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5207                                        port->parent, port);
5208                         return -EINVAL;
5209                 }
5210
5211                 pbn_used = vcpi->pbn;
5212         } else {
5213                 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5214                                                                  state);
5215                 if (pbn_used <= 0)
5216                         return pbn_used;
5217         }
5218
5219         if (pbn_used > port->full_pbn) {
5220                 drm_dbg_atomic(port->mgr->dev,
5221                                "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5222                                port->parent, port, pbn_used, port->full_pbn);
5223                 return -ENOSPC;
5224         }
5225
5226         drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5227                        port->parent, port, pbn_used, port->full_pbn);
5228
5229         return pbn_used;
5230 }
5231
5232 static inline int
5233 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5234                                          struct drm_dp_mst_topology_state *mst_state)
5235 {
5236         struct drm_dp_vcpi_allocation *vcpi;
5237         int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5238
5239         list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5240                 /* Releasing VCPI is always OK-even if the port is gone */
5241                 if (!vcpi->vcpi) {
5242                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
5243                                        vcpi->port);
5244                         continue;
5245                 }
5246
5247                 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
5248                                vcpi->port, vcpi->vcpi);
5249
5250                 avail_slots -= vcpi->vcpi;
5251                 if (avail_slots < 0) {
5252                         drm_dbg_atomic(mgr->dev,
5253                                        "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5254                                        vcpi->port, mst_state, avail_slots + vcpi->vcpi);
5255                         return -ENOSPC;
5256                 }
5257
5258                 if (++payload_count > mgr->max_payloads) {
5259                         drm_dbg_atomic(mgr->dev,
5260                                        "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5261                                        mgr, mst_state, mgr->max_payloads);
5262                         return -EINVAL;
5263                 }
5264         }
5265         drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5266                        mgr, mst_state, avail_slots, mst_state->total_avail_slots - avail_slots);
5267
5268         return 0;
5269 }
5270
5271 /**
5272  * drm_dp_mst_add_affected_dsc_crtcs
5273  * @state: Pointer to the new struct drm_dp_mst_topology_state
5274  * @mgr: MST topology manager
5275  *
5276  * Whenever there is a change in mst topology
5277  * DSC configuration would have to be recalculated
5278  * therefore we need to trigger modeset on all affected
5279  * CRTCs in that topology
5280  *
5281  * See also:
5282  * drm_dp_mst_atomic_enable_dsc()
5283  */
5284 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5285 {
5286         struct drm_dp_mst_topology_state *mst_state;
5287         struct drm_dp_vcpi_allocation *pos;
5288         struct drm_connector *connector;
5289         struct drm_connector_state *conn_state;
5290         struct drm_crtc *crtc;
5291         struct drm_crtc_state *crtc_state;
5292
5293         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5294
5295         if (IS_ERR(mst_state))
5296                 return -EINVAL;
5297
5298         list_for_each_entry(pos, &mst_state->vcpis, next) {
5299
5300                 connector = pos->port->connector;
5301
5302                 if (!connector)
5303                         return -EINVAL;
5304
5305                 conn_state = drm_atomic_get_connector_state(state, connector);
5306
5307                 if (IS_ERR(conn_state))
5308                         return PTR_ERR(conn_state);
5309
5310                 crtc = conn_state->crtc;
5311
5312                 if (!crtc)
5313                         continue;
5314
5315                 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5316                         continue;
5317
5318                 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5319
5320                 if (IS_ERR(crtc_state))
5321                         return PTR_ERR(crtc_state);
5322
5323                 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5324                                mgr, crtc);
5325
5326                 crtc_state->mode_changed = true;
5327         }
5328         return 0;
5329 }
5330 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5331
5332 /**
5333  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5334  * @state: Pointer to the new drm_atomic_state
5335  * @port: Pointer to the affected MST Port
5336  * @pbn: Newly recalculated bw required for link with DSC enabled
5337  * @pbn_div: Divider to calculate correct number of pbn per slot
5338  * @enable: Boolean flag to enable or disable DSC on the port
5339  *
5340  * This function enables DSC on the given Port
5341  * by recalculating its vcpi from pbn provided
5342  * and sets dsc_enable flag to keep track of which
5343  * ports have DSC enabled
5344  *
5345  */
5346 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5347                                  struct drm_dp_mst_port *port,
5348                                  int pbn, int pbn_div,
5349                                  bool enable)
5350 {
5351         struct drm_dp_mst_topology_state *mst_state;
5352         struct drm_dp_vcpi_allocation *pos;
5353         bool found = false;
5354         int vcpi = 0;
5355
5356         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5357
5358         if (IS_ERR(mst_state))
5359                 return PTR_ERR(mst_state);
5360
5361         list_for_each_entry(pos, &mst_state->vcpis, next) {
5362                 if (pos->port == port) {
5363                         found = true;
5364                         break;
5365                 }
5366         }
5367
5368         if (!found) {
5369                 drm_dbg_atomic(state->dev,
5370                                "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5371                                port, mst_state);
5372                 return -EINVAL;
5373         }
5374
5375         if (pos->dsc_enabled == enable) {
5376                 drm_dbg_atomic(state->dev,
5377                                "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5378                                port, enable, pos->vcpi);
5379                 vcpi = pos->vcpi;
5380         }
5381
5382         if (enable) {
5383                 vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5384                 drm_dbg_atomic(state->dev,
5385                                "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5386                                port, vcpi);
5387                 if (vcpi < 0)
5388                         return -EINVAL;
5389         }
5390
5391         pos->dsc_enabled = enable;
5392
5393         return vcpi;
5394 }
5395 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5396 /**
5397  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5398  * atomic update is valid
5399  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5400  *
5401  * Checks the given topology state for an atomic update to ensure that it's
5402  * valid. This includes checking whether there's enough bandwidth to support
5403  * the new VCPI allocations in the atomic update.
5404  *
5405  * Any atomic drivers supporting DP MST must make sure to call this after
5406  * checking the rest of their state in their
5407  * &drm_mode_config_funcs.atomic_check() callback.
5408  *
5409  * See also:
5410  * drm_dp_atomic_find_vcpi_slots()
5411  * drm_dp_atomic_release_vcpi_slots()
5412  *
5413  * Returns:
5414  *
5415  * 0 if the new state is valid, negative error code otherwise.
5416  */
5417 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5418 {
5419         struct drm_dp_mst_topology_mgr *mgr;
5420         struct drm_dp_mst_topology_state *mst_state;
5421         int i, ret = 0;
5422
5423         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5424                 if (!mgr->mst_state)
5425                         continue;
5426
5427                 ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5428                 if (ret)
5429                         break;
5430
5431                 mutex_lock(&mgr->lock);
5432                 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5433                                                             mst_state);
5434                 mutex_unlock(&mgr->lock);
5435                 if (ret < 0)
5436                         break;
5437                 else
5438                         ret = 0;
5439         }
5440
5441         return ret;
5442 }
5443 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5444
5445 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5446         .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5447         .atomic_destroy_state = drm_dp_mst_destroy_state,
5448 };
5449 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5450
5451 /**
5452  * drm_atomic_get_mst_topology_state: get MST topology state
5453  *
5454  * @state: global atomic state
5455  * @mgr: MST topology manager, also the private object in this case
5456  *
5457  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5458  * state vtable so that the private object state returned is that of a MST
5459  * topology object.
5460  *
5461  * RETURNS:
5462  *
5463  * The MST topology state or error pointer.
5464  */
5465 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5466                                                                     struct drm_dp_mst_topology_mgr *mgr)
5467 {
5468         return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5469 }
5470 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5471
5472 /**
5473  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5474  * @mgr: manager struct to initialise
5475  * @dev: device providing this structure - for i2c addition.
5476  * @aux: DP helper aux channel to talk to this device
5477  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5478  * @max_payloads: maximum number of payloads this GPU can source
5479  * @max_lane_count: maximum number of lanes this GPU supports
5480  * @max_link_rate: maximum link rate per lane this GPU supports in kHz
5481  * @conn_base_id: the connector object ID the MST device is connected to.
5482  *
5483  * Return 0 for success, or negative error code on failure
5484  */
5485 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5486                                  struct drm_device *dev, struct drm_dp_aux *aux,
5487                                  int max_dpcd_transaction_bytes, int max_payloads,
5488                                  int max_lane_count, int max_link_rate,
5489                                  int conn_base_id)
5490 {
5491         struct drm_dp_mst_topology_state *mst_state;
5492
5493         mutex_init(&mgr->lock);
5494         mutex_init(&mgr->qlock);
5495         mutex_init(&mgr->payload_lock);
5496         mutex_init(&mgr->delayed_destroy_lock);
5497         mutex_init(&mgr->up_req_lock);
5498         mutex_init(&mgr->probe_lock);
5499 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5500         mutex_init(&mgr->topology_ref_history_lock);
5501         stack_depot_init();
5502 #endif
5503         INIT_LIST_HEAD(&mgr->tx_msg_downq);
5504         INIT_LIST_HEAD(&mgr->destroy_port_list);
5505         INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5506         INIT_LIST_HEAD(&mgr->up_req_list);
5507
5508         /*
5509          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5510          * requeuing will be also flushed when deiniting the topology manager.
5511          */
5512         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5513         if (mgr->delayed_destroy_wq == NULL)
5514                 return -ENOMEM;
5515
5516         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5517         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5518         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5519         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5520         init_waitqueue_head(&mgr->tx_waitq);
5521         mgr->dev = dev;
5522         mgr->aux = aux;
5523         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5524         mgr->max_payloads = max_payloads;
5525         mgr->max_lane_count = max_lane_count;
5526         mgr->max_link_rate = max_link_rate;
5527         mgr->conn_base_id = conn_base_id;
5528         if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5529             max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5530                 return -EINVAL;
5531         mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5532         if (!mgr->payloads)
5533                 return -ENOMEM;
5534         mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5535         if (!mgr->proposed_vcpis)
5536                 return -ENOMEM;
5537         set_bit(0, &mgr->payload_mask);
5538
5539         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5540         if (mst_state == NULL)
5541                 return -ENOMEM;
5542
5543         mst_state->total_avail_slots = 63;
5544         mst_state->start_slot = 1;
5545
5546         mst_state->mgr = mgr;
5547         INIT_LIST_HEAD(&mst_state->vcpis);
5548
5549         drm_atomic_private_obj_init(dev, &mgr->base,
5550                                     &mst_state->base,
5551                                     &drm_dp_mst_topology_state_funcs);
5552
5553         return 0;
5554 }
5555 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5556
5557 /**
5558  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5559  * @mgr: manager to destroy
5560  */
5561 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5562 {
5563         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5564         flush_work(&mgr->work);
5565         /* The following will also drain any requeued work on the WQ. */
5566         if (mgr->delayed_destroy_wq) {
5567                 destroy_workqueue(mgr->delayed_destroy_wq);
5568                 mgr->delayed_destroy_wq = NULL;
5569         }
5570         mutex_lock(&mgr->payload_lock);
5571         kfree(mgr->payloads);
5572         mgr->payloads = NULL;
5573         kfree(mgr->proposed_vcpis);
5574         mgr->proposed_vcpis = NULL;
5575         mutex_unlock(&mgr->payload_lock);
5576         mgr->dev = NULL;
5577         mgr->aux = NULL;
5578         drm_atomic_private_obj_fini(&mgr->base);
5579         mgr->funcs = NULL;
5580
5581         mutex_destroy(&mgr->delayed_destroy_lock);
5582         mutex_destroy(&mgr->payload_lock);
5583         mutex_destroy(&mgr->qlock);
5584         mutex_destroy(&mgr->lock);
5585         mutex_destroy(&mgr->up_req_lock);
5586         mutex_destroy(&mgr->probe_lock);
5587 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5588         mutex_destroy(&mgr->topology_ref_history_lock);
5589 #endif
5590 }
5591 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5592
5593 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5594 {
5595         int i;
5596
5597         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5598                 return false;
5599
5600         for (i = 0; i < num - 1; i++) {
5601                 if (msgs[i].flags & I2C_M_RD ||
5602                     msgs[i].len > 0xff)
5603                         return false;
5604         }
5605
5606         return msgs[num - 1].flags & I2C_M_RD &&
5607                 msgs[num - 1].len <= 0xff;
5608 }
5609
5610 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5611 {
5612         int i;
5613
5614         for (i = 0; i < num - 1; i++) {
5615                 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5616                     msgs[i].len > 0xff)
5617                         return false;
5618         }
5619
5620         return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5621 }
5622
5623 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5624                                struct drm_dp_mst_port *port,
5625                                struct i2c_msg *msgs, int num)
5626 {
5627         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5628         unsigned int i;
5629         struct drm_dp_sideband_msg_req_body msg;
5630         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5631         int ret;
5632
5633         memset(&msg, 0, sizeof(msg));
5634         msg.req_type = DP_REMOTE_I2C_READ;
5635         msg.u.i2c_read.num_transactions = num - 1;
5636         msg.u.i2c_read.port_number = port->port_num;
5637         for (i = 0; i < num - 1; i++) {
5638                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5639                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5640                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5641                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5642         }
5643         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5644         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5645
5646         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5647         if (!txmsg) {
5648                 ret = -ENOMEM;
5649                 goto out;
5650         }
5651
5652         txmsg->dst = mstb;
5653         drm_dp_encode_sideband_req(&msg, txmsg);
5654
5655         drm_dp_queue_down_tx(mgr, txmsg);
5656
5657         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5658         if (ret > 0) {
5659
5660                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5661                         ret = -EREMOTEIO;
5662                         goto out;
5663                 }
5664                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5665                         ret = -EIO;
5666                         goto out;
5667                 }
5668                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5669                 ret = num;
5670         }
5671 out:
5672         kfree(txmsg);
5673         return ret;
5674 }
5675
5676 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5677                                 struct drm_dp_mst_port *port,
5678                                 struct i2c_msg *msgs, int num)
5679 {
5680         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5681         unsigned int i;
5682         struct drm_dp_sideband_msg_req_body msg;
5683         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5684         int ret;
5685
5686         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5687         if (!txmsg) {
5688                 ret = -ENOMEM;
5689                 goto out;
5690         }
5691         for (i = 0; i < num; i++) {
5692                 memset(&msg, 0, sizeof(msg));
5693                 msg.req_type = DP_REMOTE_I2C_WRITE;
5694                 msg.u.i2c_write.port_number = port->port_num;
5695                 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5696                 msg.u.i2c_write.num_bytes = msgs[i].len;
5697                 msg.u.i2c_write.bytes = msgs[i].buf;
5698
5699                 memset(txmsg, 0, sizeof(*txmsg));
5700                 txmsg->dst = mstb;
5701
5702                 drm_dp_encode_sideband_req(&msg, txmsg);
5703                 drm_dp_queue_down_tx(mgr, txmsg);
5704
5705                 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5706                 if (ret > 0) {
5707                         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5708                                 ret = -EREMOTEIO;
5709                                 goto out;
5710                         }
5711                 } else {
5712                         goto out;
5713                 }
5714         }
5715         ret = num;
5716 out:
5717         kfree(txmsg);
5718         return ret;
5719 }
5720
5721 /* I2C device */
5722 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5723                                struct i2c_msg *msgs, int num)
5724 {
5725         struct drm_dp_aux *aux = adapter->algo_data;
5726         struct drm_dp_mst_port *port =
5727                 container_of(aux, struct drm_dp_mst_port, aux);
5728         struct drm_dp_mst_branch *mstb;
5729         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5730         int ret;
5731
5732         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5733         if (!mstb)
5734                 return -EREMOTEIO;
5735
5736         if (remote_i2c_read_ok(msgs, num)) {
5737                 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5738         } else if (remote_i2c_write_ok(msgs, num)) {
5739                 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5740         } else {
5741                 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5742                 ret = -EIO;
5743         }
5744
5745         drm_dp_mst_topology_put_mstb(mstb);
5746         return ret;
5747 }
5748
5749 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5750 {
5751         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5752                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5753                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5754                I2C_FUNC_10BIT_ADDR;
5755 }
5756
5757 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5758         .functionality = drm_dp_mst_i2c_functionality,
5759         .master_xfer = drm_dp_mst_i2c_xfer,
5760 };
5761
5762 /**
5763  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5764  * @port: The port to add the I2C bus on
5765  *
5766  * Returns 0 on success or a negative error code on failure.
5767  */
5768 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5769 {
5770         struct drm_dp_aux *aux = &port->aux;
5771         struct device *parent_dev = port->mgr->dev->dev;
5772
5773         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5774         aux->ddc.algo_data = aux;
5775         aux->ddc.retries = 3;
5776
5777         aux->ddc.class = I2C_CLASS_DDC;
5778         aux->ddc.owner = THIS_MODULE;
5779         /* FIXME: set the kdev of the port's connector as parent */
5780         aux->ddc.dev.parent = parent_dev;
5781         aux->ddc.dev.of_node = parent_dev->of_node;
5782
5783         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5784                 sizeof(aux->ddc.name));
5785
5786         return i2c_add_adapter(&aux->ddc);
5787 }
5788
5789 /**
5790  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5791  * @port: The port to remove the I2C bus from
5792  */
5793 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5794 {
5795         i2c_del_adapter(&port->aux.ddc);
5796 }
5797
5798 /**
5799  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5800  * @port: The port to check
5801  *
5802  * A single physical MST hub object can be represented in the topology
5803  * by multiple branches, with virtual ports between those branches.
5804  *
5805  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5806  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5807  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5808  *
5809  * May acquire mgr->lock
5810  *
5811  * Returns:
5812  * true if the port is a virtual DP peer device, false otherwise
5813  */
5814 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5815 {
5816         struct drm_dp_mst_port *downstream_port;
5817
5818         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5819                 return false;
5820
5821         /* Virtual DP Sink (Internal Display Panel) */
5822         if (port->port_num >= 8)
5823                 return true;
5824
5825         /* DP-to-HDMI Protocol Converter */
5826         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5827             !port->mcs &&
5828             port->ldps)
5829                 return true;
5830
5831         /* DP-to-DP */
5832         mutex_lock(&port->mgr->lock);
5833         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5834             port->mstb &&
5835             port->mstb->num_ports == 2) {
5836                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5837                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5838                             !downstream_port->input) {
5839                                 mutex_unlock(&port->mgr->lock);
5840                                 return true;
5841                         }
5842                 }
5843         }
5844         mutex_unlock(&port->mgr->lock);
5845
5846         return false;
5847 }
5848
5849 /**
5850  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5851  * @port: The port to check. A leaf of the MST tree with an attached display.
5852  *
5853  * Depending on the situation, DSC may be enabled via the endpoint aux,
5854  * the immediately upstream aux, or the connector's physical aux.
5855  *
5856  * This is both the correct aux to read DSC_CAPABILITY and the
5857  * correct aux to write DSC_ENABLED.
5858  *
5859  * This operation can be expensive (up to four aux reads), so
5860  * the caller should cache the return.
5861  *
5862  * Returns:
5863  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5864  */
5865 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5866 {
5867         struct drm_dp_mst_port *immediate_upstream_port;
5868         struct drm_dp_mst_port *fec_port;
5869         struct drm_dp_desc desc = {};
5870         u8 endpoint_fec;
5871         u8 endpoint_dsc;
5872
5873         if (!port)
5874                 return NULL;
5875
5876         if (port->parent->port_parent)
5877                 immediate_upstream_port = port->parent->port_parent;
5878         else
5879                 immediate_upstream_port = NULL;
5880
5881         fec_port = immediate_upstream_port;
5882         while (fec_port) {
5883                 /*
5884                  * Each physical link (i.e. not a virtual port) between the
5885                  * output and the primary device must support FEC
5886                  */
5887                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5888                     !fec_port->fec_capable)
5889                         return NULL;
5890
5891                 fec_port = fec_port->parent->port_parent;
5892         }
5893
5894         /* DP-to-DP peer device */
5895         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5896                 u8 upstream_dsc;
5897
5898                 if (drm_dp_dpcd_read(&port->aux,
5899                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5900                         return NULL;
5901                 if (drm_dp_dpcd_read(&port->aux,
5902                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5903                         return NULL;
5904                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5905                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5906                         return NULL;
5907
5908                 /* Enpoint decompression with DP-to-DP peer device */
5909                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5910                     (endpoint_fec & DP_FEC_CAPABLE) &&
5911                     (upstream_dsc & 0x2) /* DSC passthrough */)
5912                         return &port->aux;
5913
5914                 /* Virtual DPCD decompression with DP-to-DP peer device */
5915                 return &immediate_upstream_port->aux;
5916         }
5917
5918         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5919         if (drm_dp_mst_is_virtual_dpcd(port))
5920                 return &port->aux;
5921
5922         /*
5923          * Synaptics quirk
5924          * Applies to ports for which:
5925          * - Physical aux has Synaptics OUI
5926          * - DPv1.4 or higher
5927          * - Port is on primary branch device
5928          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5929          */
5930         if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5931                 return NULL;
5932
5933         if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5934             port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5935             port->parent == port->mgr->mst_primary) {
5936                 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5937
5938                 if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5939                         return NULL;
5940
5941                 if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5942                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5943                      != DP_DWN_STRM_PORT_TYPE_ANALOG))
5944                         return port->mgr->aux;
5945         }
5946
5947         /*
5948          * The check below verifies if the MST sink
5949          * connected to the GPU is capable of DSC -
5950          * therefore the endpoint needs to be
5951          * both DSC and FEC capable.
5952          */
5953         if (drm_dp_dpcd_read(&port->aux,
5954            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5955                 return NULL;
5956         if (drm_dp_dpcd_read(&port->aux,
5957            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5958                 return NULL;
5959         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5960            (endpoint_fec & DP_FEC_CAPABLE))
5961                 return &port->aux;
5962
5963         return NULL;
5964 }
5965 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);