2 * Copyright © 2014 Red Hat
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.
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
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>
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>
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>
49 #include "drm_dp_helper_internal.h"
50 #include "drm_dp_mst_topology_internal.h"
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.
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;
65 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
68 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
70 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
71 int id, u8 start_slot, u8 num_slots);
73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
74 struct drm_dp_mst_port *port,
75 int offset, int size, u8 *bytes);
76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
77 struct drm_dp_mst_port *port,
78 int offset, int size, u8 *bytes);
80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
81 struct drm_dp_mst_branch *mstb);
84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
85 struct drm_dp_mst_branch *mstb);
87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
88 struct drm_dp_mst_branch *mstb,
89 struct drm_dp_mst_port *port);
90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
97 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
98 struct drm_dp_mst_branch *branch);
100 #define DBG_PREFIX "[dp_mst]"
102 #define DP_STR(x) [DP_ ## x] = #x
104 static const char *drm_dp_mst_req_type_str(u8 req_type)
106 static const char * const req_type_str[] = {
107 DP_STR(GET_MSG_TRANSACTION_VERSION),
108 DP_STR(LINK_ADDRESS),
109 DP_STR(CONNECTION_STATUS_NOTIFY),
110 DP_STR(ENUM_PATH_RESOURCES),
111 DP_STR(ALLOCATE_PAYLOAD),
112 DP_STR(QUERY_PAYLOAD),
113 DP_STR(RESOURCE_STATUS_NOTIFY),
114 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
115 DP_STR(REMOTE_DPCD_READ),
116 DP_STR(REMOTE_DPCD_WRITE),
117 DP_STR(REMOTE_I2C_READ),
118 DP_STR(REMOTE_I2C_WRITE),
119 DP_STR(POWER_UP_PHY),
120 DP_STR(POWER_DOWN_PHY),
121 DP_STR(SINK_EVENT_NOTIFY),
122 DP_STR(QUERY_STREAM_ENC_STATUS),
125 if (req_type >= ARRAY_SIZE(req_type_str) ||
126 !req_type_str[req_type])
129 return req_type_str[req_type];
133 #define DP_STR(x) [DP_NAK_ ## x] = #x
135 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
137 static const char * const nak_reason_str[] = {
138 DP_STR(WRITE_FAILURE),
139 DP_STR(INVALID_READ),
143 DP_STR(LINK_FAILURE),
144 DP_STR(NO_RESOURCES),
147 DP_STR(ALLOCATE_FAIL),
150 if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
151 !nak_reason_str[nak_reason])
154 return nak_reason_str[nak_reason];
158 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
160 static const char *drm_dp_mst_sideband_tx_state_str(int state)
162 static const char * const sideband_reason_str[] = {
170 if (state >= ARRAY_SIZE(sideband_reason_str) ||
171 !sideband_reason_str[state])
174 return sideband_reason_str[state];
178 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
183 for (i = 0; i < lct; i++) {
185 unpacked_rad[i] = rad[i / 2] >> 4;
187 unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
190 /* TODO: Eventually add something to printk so we can format the rad
193 return snprintf(out, len, "%*phC", lct, unpacked_rad);
196 /* sideband msg handling */
197 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
202 int number_of_bits = num_nibbles * 4;
205 while (number_of_bits != 0) {
208 remainder |= (data[array_index] & bitmask) >> bitshift;
216 if ((remainder & 0x10) == 0x10)
221 while (number_of_bits != 0) {
224 if ((remainder & 0x10) != 0)
231 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
236 int number_of_bits = number_of_bytes * 8;
239 while (number_of_bits != 0) {
242 remainder |= (data[array_index] & bitmask) >> bitshift;
250 if ((remainder & 0x100) == 0x100)
255 while (number_of_bits != 0) {
258 if ((remainder & 0x100) != 0)
262 return remainder & 0xff;
264 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
268 size += (hdr->lct / 2);
272 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
279 buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
280 for (i = 0; i < (hdr->lct / 2); i++)
281 buf[idx++] = hdr->rad[i];
282 buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
283 (hdr->msg_len & 0x3f);
284 buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
286 crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
287 buf[idx - 1] |= (crc4 & 0xf);
292 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
293 struct drm_dp_sideband_msg_hdr *hdr,
294 u8 *buf, int buflen, u8 *hdrlen)
304 len += ((buf[0] & 0xf0) >> 4) / 2;
307 crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
309 if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
310 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
314 hdr->lct = (buf[0] & 0xf0) >> 4;
315 hdr->lcr = (buf[0] & 0xf);
317 for (i = 0; i < (hdr->lct / 2); i++)
318 hdr->rad[i] = buf[idx++];
319 hdr->broadcast = (buf[idx] >> 7) & 0x1;
320 hdr->path_msg = (buf[idx] >> 6) & 0x1;
321 hdr->msg_len = buf[idx] & 0x3f;
323 hdr->somt = (buf[idx] >> 7) & 0x1;
324 hdr->eomt = (buf[idx] >> 6) & 0x1;
325 hdr->seqno = (buf[idx] >> 4) & 0x1;
332 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
333 struct drm_dp_sideband_msg_tx *raw)
339 buf[idx++] = req->req_type & 0x7f;
341 switch (req->req_type) {
342 case DP_ENUM_PATH_RESOURCES:
343 case DP_POWER_DOWN_PHY:
344 case DP_POWER_UP_PHY:
345 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
348 case DP_ALLOCATE_PAYLOAD:
349 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
350 (req->u.allocate_payload.number_sdp_streams & 0xf);
352 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
354 buf[idx] = (req->u.allocate_payload.pbn >> 8);
356 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
358 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
359 buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
360 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
363 if (req->u.allocate_payload.number_sdp_streams & 1) {
364 i = req->u.allocate_payload.number_sdp_streams - 1;
365 buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
369 case DP_QUERY_PAYLOAD:
370 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
372 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
375 case DP_REMOTE_DPCD_READ:
376 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
377 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
379 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
381 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
383 buf[idx] = (req->u.dpcd_read.num_bytes);
387 case DP_REMOTE_DPCD_WRITE:
388 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
389 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
391 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
393 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
395 buf[idx] = (req->u.dpcd_write.num_bytes);
397 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
398 idx += req->u.dpcd_write.num_bytes;
400 case DP_REMOTE_I2C_READ:
401 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
402 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
404 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
405 buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
407 buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
409 memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
410 idx += req->u.i2c_read.transactions[i].num_bytes;
412 buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
413 buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
416 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
418 buf[idx] = (req->u.i2c_read.num_bytes_read);
422 case DP_REMOTE_I2C_WRITE:
423 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
425 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
427 buf[idx] = (req->u.i2c_write.num_bytes);
429 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
430 idx += req->u.i2c_write.num_bytes;
432 case DP_QUERY_STREAM_ENC_STATUS: {
433 const struct drm_dp_query_stream_enc_status *msg;
435 msg = &req->u.enc_status;
436 buf[idx] = msg->stream_id;
438 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
439 idx += sizeof(msg->client_id);
441 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
442 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
443 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
444 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
451 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
453 /* Decode a sideband request we've encoded, mainly used for debugging */
455 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
456 struct drm_dp_sideband_msg_req_body *req)
458 const u8 *buf = raw->msg;
461 req->req_type = buf[idx++] & 0x7f;
462 switch (req->req_type) {
463 case DP_ENUM_PATH_RESOURCES:
464 case DP_POWER_DOWN_PHY:
465 case DP_POWER_UP_PHY:
466 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
468 case DP_ALLOCATE_PAYLOAD:
470 struct drm_dp_allocate_payload *a =
471 &req->u.allocate_payload;
473 a->number_sdp_streams = buf[idx] & 0xf;
474 a->port_number = (buf[idx] >> 4) & 0xf;
476 WARN_ON(buf[++idx] & 0x80);
477 a->vcpi = buf[idx] & 0x7f;
479 a->pbn = buf[++idx] << 8;
480 a->pbn |= buf[++idx];
483 for (i = 0; i < a->number_sdp_streams; i++) {
484 a->sdp_stream_sink[i] =
485 (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
489 case DP_QUERY_PAYLOAD:
490 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
491 WARN_ON(buf[++idx] & 0x80);
492 req->u.query_payload.vcpi = buf[idx] & 0x7f;
494 case DP_REMOTE_DPCD_READ:
496 struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
498 r->port_number = (buf[idx] >> 4) & 0xf;
500 r->dpcd_address = (buf[idx] << 16) & 0xf0000;
501 r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
502 r->dpcd_address |= buf[++idx] & 0xff;
504 r->num_bytes = buf[++idx];
507 case DP_REMOTE_DPCD_WRITE:
509 struct drm_dp_remote_dpcd_write *w =
512 w->port_number = (buf[idx] >> 4) & 0xf;
514 w->dpcd_address = (buf[idx] << 16) & 0xf0000;
515 w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
516 w->dpcd_address |= buf[++idx] & 0xff;
518 w->num_bytes = buf[++idx];
520 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
526 case DP_REMOTE_I2C_READ:
528 struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
529 struct drm_dp_remote_i2c_read_tx *tx;
532 r->num_transactions = buf[idx] & 0x3;
533 r->port_number = (buf[idx] >> 4) & 0xf;
534 for (i = 0; i < r->num_transactions; i++) {
535 tx = &r->transactions[i];
537 tx->i2c_dev_id = buf[++idx] & 0x7f;
538 tx->num_bytes = buf[++idx];
539 tx->bytes = kmemdup(&buf[++idx],
546 idx += tx->num_bytes;
547 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
548 tx->i2c_transaction_delay = buf[idx] & 0xf;
552 for (i = 0; i < r->num_transactions; i++) {
553 tx = &r->transactions[i];
559 r->read_i2c_device_id = buf[++idx] & 0x7f;
560 r->num_bytes_read = buf[++idx];
563 case DP_REMOTE_I2C_WRITE:
565 struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
567 w->port_number = (buf[idx] >> 4) & 0xf;
568 w->write_i2c_device_id = buf[++idx] & 0x7f;
569 w->num_bytes = buf[++idx];
570 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
576 case DP_QUERY_STREAM_ENC_STATUS:
577 req->u.enc_status.stream_id = buf[idx++];
578 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
579 req->u.enc_status.client_id[i] = buf[idx++];
581 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
583 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
585 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
587 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
594 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
597 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
598 int indent, struct drm_printer *printer)
602 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
603 if (req->req_type == DP_LINK_ADDRESS) {
604 /* No contents to print */
605 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
609 P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
612 switch (req->req_type) {
613 case DP_ENUM_PATH_RESOURCES:
614 case DP_POWER_DOWN_PHY:
615 case DP_POWER_UP_PHY:
616 P("port=%d\n", req->u.port_num.port_number);
618 case DP_ALLOCATE_PAYLOAD:
619 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
620 req->u.allocate_payload.port_number,
621 req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
622 req->u.allocate_payload.number_sdp_streams,
623 req->u.allocate_payload.number_sdp_streams,
624 req->u.allocate_payload.sdp_stream_sink);
626 case DP_QUERY_PAYLOAD:
627 P("port=%d vcpi=%d\n",
628 req->u.query_payload.port_number,
629 req->u.query_payload.vcpi);
631 case DP_REMOTE_DPCD_READ:
632 P("port=%d dpcd_addr=%05x len=%d\n",
633 req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
634 req->u.dpcd_read.num_bytes);
636 case DP_REMOTE_DPCD_WRITE:
637 P("port=%d addr=%05x len=%d: %*ph\n",
638 req->u.dpcd_write.port_number,
639 req->u.dpcd_write.dpcd_address,
640 req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
641 req->u.dpcd_write.bytes);
643 case DP_REMOTE_I2C_READ:
644 P("port=%d num_tx=%d id=%d size=%d:\n",
645 req->u.i2c_read.port_number,
646 req->u.i2c_read.num_transactions,
647 req->u.i2c_read.read_i2c_device_id,
648 req->u.i2c_read.num_bytes_read);
651 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
652 const struct drm_dp_remote_i2c_read_tx *rtx =
653 &req->u.i2c_read.transactions[i];
655 P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
656 i, rtx->i2c_dev_id, rtx->num_bytes,
657 rtx->no_stop_bit, rtx->i2c_transaction_delay,
658 rtx->num_bytes, rtx->bytes);
661 case DP_REMOTE_I2C_WRITE:
662 P("port=%d id=%d size=%d: %*ph\n",
663 req->u.i2c_write.port_number,
664 req->u.i2c_write.write_i2c_device_id,
665 req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
666 req->u.i2c_write.bytes);
668 case DP_QUERY_STREAM_ENC_STATUS:
669 P("stream_id=%u client_id=%*ph stream_event=%x "
670 "valid_event=%d stream_behavior=%x valid_behavior=%d",
671 req->u.enc_status.stream_id,
672 (int)ARRAY_SIZE(req->u.enc_status.client_id),
673 req->u.enc_status.client_id, req->u.enc_status.stream_event,
674 req->u.enc_status.valid_stream_event,
675 req->u.enc_status.stream_behavior,
676 req->u.enc_status.valid_stream_behavior);
684 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
687 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
688 const struct drm_dp_sideband_msg_tx *txmsg)
690 struct drm_dp_sideband_msg_req_body req;
695 drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
697 drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
698 txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
699 drm_dp_mst_sideband_tx_state_str(txmsg->state),
700 txmsg->path_msg, buf);
702 ret = drm_dp_decode_sideband_req(txmsg, &req);
704 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
707 drm_dp_dump_sideband_msg_req_body(&req, 1, p);
709 switch (req.req_type) {
710 case DP_REMOTE_DPCD_WRITE:
711 kfree(req.u.dpcd_write.bytes);
713 case DP_REMOTE_I2C_READ:
714 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
715 kfree(req.u.i2c_read.transactions[i].bytes);
717 case DP_REMOTE_I2C_WRITE:
718 kfree(req.u.i2c_write.bytes);
723 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
727 crc4 = drm_dp_msg_data_crc4(msg, len);
731 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
732 struct drm_dp_sideband_msg_tx *raw)
737 buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
742 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
743 struct drm_dp_sideband_msg_hdr *hdr,
747 * ignore out-of-order messages or messages that are part of a
750 if (!hdr->somt && !msg->have_somt)
753 /* get length contained in this portion */
754 msg->curchunk_idx = 0;
755 msg->curchunk_len = hdr->msg_len;
756 msg->curchunk_hdrlen = hdrlen;
758 /* we have already gotten an somt - don't bother parsing */
759 if (hdr->somt && msg->have_somt)
763 memcpy(&msg->initial_hdr, hdr,
764 sizeof(struct drm_dp_sideband_msg_hdr));
765 msg->have_somt = true;
768 msg->have_eomt = true;
773 /* this adds a chunk of msg to the builder to get the final msg */
774 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
775 u8 *replybuf, u8 replybuflen)
779 memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
780 msg->curchunk_idx += replybuflen;
782 if (msg->curchunk_idx >= msg->curchunk_len) {
784 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
785 if (crc4 != msg->chunk[msg->curchunk_len - 1])
786 print_hex_dump(KERN_DEBUG, "wrong crc",
787 DUMP_PREFIX_NONE, 16, 1,
788 msg->chunk, msg->curchunk_len, false);
789 /* copy chunk into bigger msg */
790 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
791 msg->curlen += msg->curchunk_len - 1;
796 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
797 struct drm_dp_sideband_msg_rx *raw,
798 struct drm_dp_sideband_msg_reply_body *repmsg)
803 memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
805 repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
807 if (idx > raw->curlen)
809 for (i = 0; i < repmsg->u.link_addr.nports; i++) {
810 if (raw->msg[idx] & 0x80)
811 repmsg->u.link_addr.ports[i].input_port = 1;
813 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
814 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
817 if (idx > raw->curlen)
819 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
820 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
821 if (repmsg->u.link_addr.ports[i].input_port == 0)
822 repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
824 if (idx > raw->curlen)
826 if (repmsg->u.link_addr.ports[i].input_port == 0) {
827 repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
829 if (idx > raw->curlen)
831 memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
833 if (idx > raw->curlen)
835 repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
836 repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
840 if (idx > raw->curlen)
846 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
850 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
851 struct drm_dp_sideband_msg_reply_body *repmsg)
855 repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
857 if (idx > raw->curlen)
859 repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
861 if (idx > raw->curlen)
864 memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
867 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
871 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
872 struct drm_dp_sideband_msg_reply_body *repmsg)
876 repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
878 if (idx > raw->curlen)
882 DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
886 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
887 struct drm_dp_sideband_msg_reply_body *repmsg)
891 repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
893 if (idx > raw->curlen)
895 repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
898 memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
901 DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
905 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
906 struct drm_dp_sideband_msg_reply_body *repmsg)
910 repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
911 repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
913 if (idx > raw->curlen)
915 repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
917 if (idx > raw->curlen)
919 repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
921 if (idx > raw->curlen)
925 DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
929 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
930 struct drm_dp_sideband_msg_reply_body *repmsg)
934 repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
936 if (idx > raw->curlen)
938 repmsg->u.allocate_payload.vcpi = raw->msg[idx];
940 if (idx > raw->curlen)
942 repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
944 if (idx > raw->curlen)
948 DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
952 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
953 struct drm_dp_sideband_msg_reply_body *repmsg)
957 repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
959 if (idx > raw->curlen)
961 repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
963 if (idx > raw->curlen)
967 DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
971 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
972 struct drm_dp_sideband_msg_reply_body *repmsg)
976 repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
978 if (idx > raw->curlen) {
979 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
987 drm_dp_sideband_parse_query_stream_enc_status(
988 struct drm_dp_sideband_msg_rx *raw,
989 struct drm_dp_sideband_msg_reply_body *repmsg)
991 struct drm_dp_query_stream_enc_status_ack_reply *reply;
993 reply = &repmsg->u.enc_status;
995 reply->stream_id = raw->msg[3];
997 reply->reply_signed = raw->msg[2] & BIT(0);
1000 * NOTE: It's my impression from reading the spec that the below parsing
1001 * is correct. However I noticed while testing with an HDCP 1.4 display
1002 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003 * would expect both bits to be set. So keep the parsing following the
1004 * spec, but beware reality might not match the spec (at least for some
1007 reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008 reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1010 reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011 reply->legacy_device_present = raw->msg[2] & BIT(6);
1012 reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1014 reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015 reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016 reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017 reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1022 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023 struct drm_dp_sideband_msg_rx *raw,
1024 struct drm_dp_sideband_msg_reply_body *msg)
1026 memset(msg, 0, sizeof(*msg));
1027 msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028 msg->req_type = (raw->msg[0] & 0x7f);
1030 if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032 msg->u.nak.reason = raw->msg[17];
1033 msg->u.nak.nak_data = raw->msg[18];
1037 switch (msg->req_type) {
1038 case DP_LINK_ADDRESS:
1039 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040 case DP_QUERY_PAYLOAD:
1041 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042 case DP_REMOTE_DPCD_READ:
1043 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044 case DP_REMOTE_DPCD_WRITE:
1045 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046 case DP_REMOTE_I2C_READ:
1047 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048 case DP_REMOTE_I2C_WRITE:
1049 return true; /* since there's nothing to parse */
1050 case DP_ENUM_PATH_RESOURCES:
1051 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052 case DP_ALLOCATE_PAYLOAD:
1053 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054 case DP_POWER_DOWN_PHY:
1055 case DP_POWER_UP_PHY:
1056 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057 case DP_CLEAR_PAYLOAD_ID_TABLE:
1058 return true; /* since there's nothing to parse */
1059 case DP_QUERY_STREAM_ENC_STATUS:
1060 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1062 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063 msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1069 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070 struct drm_dp_sideband_msg_rx *raw,
1071 struct drm_dp_sideband_msg_req_body *msg)
1075 msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1077 if (idx > raw->curlen)
1080 memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1082 if (idx > raw->curlen)
1085 msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086 msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087 msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088 msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089 msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1093 drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1098 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099 struct drm_dp_sideband_msg_rx *raw,
1100 struct drm_dp_sideband_msg_req_body *msg)
1104 msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1106 if (idx > raw->curlen)
1109 memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1111 if (idx > raw->curlen)
1114 msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1118 drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1122 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123 struct drm_dp_sideband_msg_rx *raw,
1124 struct drm_dp_sideband_msg_req_body *msg)
1126 memset(msg, 0, sizeof(*msg));
1127 msg->req_type = (raw->msg[0] & 0x7f);
1129 switch (msg->req_type) {
1130 case DP_CONNECTION_STATUS_NOTIFY:
1131 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132 case DP_RESOURCE_STATUS_NOTIFY:
1133 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1135 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136 msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1141 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142 u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1144 struct drm_dp_sideband_msg_req_body req;
1146 req.req_type = DP_REMOTE_DPCD_WRITE;
1147 req.u.dpcd_write.port_number = port_num;
1148 req.u.dpcd_write.dpcd_address = offset;
1149 req.u.dpcd_write.num_bytes = num_bytes;
1150 req.u.dpcd_write.bytes = bytes;
1151 drm_dp_encode_sideband_req(&req, msg);
1154 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1156 struct drm_dp_sideband_msg_req_body req;
1158 req.req_type = DP_LINK_ADDRESS;
1159 drm_dp_encode_sideband_req(&req, msg);
1162 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1164 struct drm_dp_sideband_msg_req_body req;
1166 req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167 drm_dp_encode_sideband_req(&req, msg);
1168 msg->path_msg = true;
1171 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1174 struct drm_dp_sideband_msg_req_body req;
1176 req.req_type = DP_ENUM_PATH_RESOURCES;
1177 req.u.port_num.port_number = port_num;
1178 drm_dp_encode_sideband_req(&req, msg);
1179 msg->path_msg = true;
1183 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1185 u8 vcpi, uint16_t pbn,
1186 u8 number_sdp_streams,
1187 u8 *sdp_stream_sink)
1189 struct drm_dp_sideband_msg_req_body req;
1191 memset(&req, 0, sizeof(req));
1192 req.req_type = DP_ALLOCATE_PAYLOAD;
1193 req.u.allocate_payload.port_number = port_num;
1194 req.u.allocate_payload.vcpi = vcpi;
1195 req.u.allocate_payload.pbn = pbn;
1196 req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197 memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198 number_sdp_streams);
1199 drm_dp_encode_sideband_req(&req, msg);
1200 msg->path_msg = true;
1203 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204 int port_num, bool power_up)
1206 struct drm_dp_sideband_msg_req_body req;
1209 req.req_type = DP_POWER_UP_PHY;
1211 req.req_type = DP_POWER_DOWN_PHY;
1213 req.u.port_num.port_number = port_num;
1214 drm_dp_encode_sideband_req(&req, msg);
1215 msg->path_msg = true;
1219 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1222 struct drm_dp_sideband_msg_req_body req;
1224 req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225 req.u.enc_status.stream_id = stream_id;
1226 memcpy(req.u.enc_status.client_id, q_id,
1227 sizeof(req.u.enc_status.client_id));
1228 req.u.enc_status.stream_event = 0;
1229 req.u.enc_status.valid_stream_event = false;
1230 req.u.enc_status.stream_behavior = 0;
1231 req.u.enc_status.valid_stream_behavior = false;
1233 drm_dp_encode_sideband_req(&req, msg);
1237 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1238 struct drm_dp_sideband_msg_tx *txmsg)
1243 * All updates to txmsg->state are protected by mgr->qlock, and the two
1244 * cases we check here are terminal states. For those the barriers
1245 * provided by the wake_up/wait_event pair are enough.
1247 state = READ_ONCE(txmsg->state);
1248 return (state == DRM_DP_SIDEBAND_TX_RX ||
1249 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1252 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1253 struct drm_dp_sideband_msg_tx *txmsg)
1255 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1256 unsigned long wait_timeout = msecs_to_jiffies(4000);
1257 unsigned long wait_expires = jiffies + wait_timeout;
1262 * If the driver provides a way for this, change to
1263 * poll-waiting for the MST reply interrupt if we didn't receive
1264 * it for 50 msec. This would cater for cases where the HPD
1265 * pulse signal got lost somewhere, even though the sink raised
1266 * the corresponding MST interrupt correctly. One example is the
1267 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1268 * filters out short pulses with a duration less than ~540 usec.
1270 * The poll period is 50 msec to avoid missing an interrupt
1271 * after the sink has cleared it (after a 110msec timeout
1272 * since it raised the interrupt).
1274 ret = wait_event_timeout(mgr->tx_waitq,
1275 check_txmsg_state(mgr, txmsg),
1276 mgr->cbs->poll_hpd_irq ?
1277 msecs_to_jiffies(50) :
1280 if (ret || !mgr->cbs->poll_hpd_irq ||
1281 time_after(jiffies, wait_expires))
1284 mgr->cbs->poll_hpd_irq(mgr);
1287 mutex_lock(&mgr->qlock);
1289 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1294 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1295 txmsg, txmsg->state, txmsg->seqno);
1297 /* dump some state */
1301 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1302 txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1303 txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1304 list_del(&txmsg->next);
1307 if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1308 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1310 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1312 mutex_unlock(&mgr->qlock);
1314 drm_dp_mst_kick_tx(mgr);
1318 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1320 struct drm_dp_mst_branch *mstb;
1322 mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1328 memcpy(mstb->rad, rad, lct / 2);
1329 INIT_LIST_HEAD(&mstb->ports);
1330 kref_init(&mstb->topology_kref);
1331 kref_init(&mstb->malloc_kref);
1335 static void drm_dp_free_mst_branch_device(struct kref *kref)
1337 struct drm_dp_mst_branch *mstb =
1338 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1340 if (mstb->port_parent)
1341 drm_dp_mst_put_port_malloc(mstb->port_parent);
1347 * DOC: Branch device and port refcounting
1349 * Topology refcount overview
1350 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1352 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1353 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1354 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1356 * Topology refcounts are not exposed to drivers, and are handled internally
1357 * by the DP MST helpers. The helpers use them in order to prevent the
1358 * in-memory topology state from being changed in the middle of critical
1359 * operations like changing the internal state of payload allocations. This
1360 * means each branch and port will be considered to be connected to the rest
1361 * of the topology until its topology refcount reaches zero. Additionally,
1362 * for ports this means that their associated &struct drm_connector will stay
1363 * registered with userspace until the port's refcount reaches 0.
1365 * Malloc refcount overview
1366 * ~~~~~~~~~~~~~~~~~~~~~~~~
1368 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1369 * drm_dp_mst_branch allocated even after all of its topology references have
1370 * been dropped, so that the driver or MST helpers can safely access each
1371 * branch's last known state before it was disconnected from the topology.
1372 * When the malloc refcount of a port or branch reaches 0, the memory
1373 * allocation containing the &struct drm_dp_mst_branch or &struct
1374 * drm_dp_mst_port respectively will be freed.
1376 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1377 * to drivers. As of writing this documentation, there are no drivers that
1378 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1379 * helpers. Exposing this API to drivers in a race-free manner would take more
1380 * tweaking of the refcounting scheme, however patches are welcome provided
1381 * there is a legitimate driver usecase for this.
1383 * Refcount relationships in a topology
1384 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1386 * Let's take a look at why the relationship between topology and malloc
1387 * refcounts is designed the way it is.
1389 * .. kernel-figure:: dp-mst/topology-figure-1.dot
1391 * An example of topology and malloc refs in a DP MST topology with two
1392 * active payloads. Topology refcount increments are indicated by solid
1393 * lines, and malloc refcount increments are indicated by dashed lines.
1394 * Each starts from the branch which incremented the refcount, and ends at
1395 * the branch to which the refcount belongs to, i.e. the arrow points the
1396 * same way as the C pointers used to reference a structure.
1398 * As you can see in the above figure, every branch increments the topology
1399 * refcount of its children, and increments the malloc refcount of its
1400 * parent. Additionally, every payload increments the malloc refcount of its
1401 * assigned port by 1.
1403 * So, what would happen if MSTB #3 from the above figure was unplugged from
1404 * the system, but the driver hadn't yet removed payload #2 from port #3? The
1405 * topology would start to look like the figure below.
1407 * .. kernel-figure:: dp-mst/topology-figure-2.dot
1409 * Ports and branch devices which have been released from memory are
1410 * colored grey, and references which have been removed are colored red.
1412 * Whenever a port or branch device's topology refcount reaches zero, it will
1413 * decrement the topology refcounts of all its children, the malloc refcount
1414 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1415 * #4, this means they both have been disconnected from the topology and freed
1416 * from memory. But, because payload #2 is still holding a reference to port
1417 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1418 * is still accessible from memory. This also means port #3 has not yet
1419 * decremented the malloc refcount of MSTB #3, so its &struct
1420 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1421 * malloc refcount reaches 0.
1423 * This relationship is necessary because in order to release payload #2, we
1424 * need to be able to figure out the last relative of port #3 that's still
1425 * connected to the topology. In this case, we would travel up the topology as
1428 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1430 * And finally, remove payload #2 by communicating with port #2 through
1431 * sideband transactions.
1435 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1437 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1439 * Increments &drm_dp_mst_branch.malloc_kref. When
1440 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1441 * will be released and @mstb may no longer be used.
1443 * See also: drm_dp_mst_put_mstb_malloc()
1446 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1448 kref_get(&mstb->malloc_kref);
1449 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1453 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1455 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1457 * Decrements &drm_dp_mst_branch.malloc_kref. When
1458 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1459 * will be released and @mstb may no longer be used.
1461 * See also: drm_dp_mst_get_mstb_malloc()
1464 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1466 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1467 kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1470 static void drm_dp_free_mst_port(struct kref *kref)
1472 struct drm_dp_mst_port *port =
1473 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1475 drm_dp_mst_put_mstb_malloc(port->parent);
1480 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1481 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1483 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1484 * reaches 0, the memory allocation for @port will be released and @port may
1485 * no longer be used.
1487 * Because @port could potentially be freed at any time by the DP MST helpers
1488 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1489 * function, drivers that which to make use of &struct drm_dp_mst_port should
1490 * ensure that they grab at least one main malloc reference to their MST ports
1491 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1492 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1494 * See also: drm_dp_mst_put_port_malloc()
1497 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1499 kref_get(&port->malloc_kref);
1500 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1502 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1505 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1506 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1508 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1509 * reaches 0, the memory allocation for @port will be released and @port may
1510 * no longer be used.
1512 * See also: drm_dp_mst_get_port_malloc()
1515 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1517 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1518 kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1520 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1522 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1524 #define STACK_DEPTH 8
1526 static noinline void
1527 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1528 struct drm_dp_mst_topology_ref_history *history,
1529 enum drm_dp_mst_topology_ref_type type)
1531 struct drm_dp_mst_topology_ref_entry *entry = NULL;
1532 depot_stack_handle_t backtrace;
1533 ulong stack_entries[STACK_DEPTH];
1537 n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1538 backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1542 /* Try to find an existing entry for this backtrace */
1543 for (i = 0; i < history->len; i++) {
1544 if (history->entries[i].backtrace == backtrace) {
1545 entry = &history->entries[i];
1550 /* Otherwise add one */
1552 struct drm_dp_mst_topology_ref_entry *new;
1553 int new_len = history->len + 1;
1555 new = krealloc(history->entries, sizeof(*new) * new_len,
1560 entry = &new[history->len];
1561 history->len = new_len;
1562 history->entries = new;
1564 entry->backtrace = backtrace;
1569 entry->ts_nsec = ktime_get_ns();
1573 topology_ref_history_cmp(const void *a, const void *b)
1575 const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1577 if (entry_a->ts_nsec > entry_b->ts_nsec)
1579 else if (entry_a->ts_nsec < entry_b->ts_nsec)
1585 static inline const char *
1586 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1588 if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1595 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1596 void *ptr, const char *type_str)
1598 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1599 char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1608 /* First, sort the list so that it goes from oldest to newest
1611 sort(history->entries, history->len, sizeof(*history->entries),
1612 topology_ref_history_cmp, NULL);
1614 drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1617 for (i = 0; i < history->len; i++) {
1618 const struct drm_dp_mst_topology_ref_entry *entry =
1619 &history->entries[i];
1620 u64 ts_nsec = entry->ts_nsec;
1621 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1623 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1625 drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s",
1627 topology_ref_type_to_str(entry->type),
1628 ts_nsec, rem_nsec / 1000, buf);
1631 /* Now free the history, since this is the only time we expose it */
1632 kfree(history->entries);
1637 static __always_inline void
1638 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1640 __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1644 static __always_inline void
1645 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1647 __dump_topology_ref_history(&port->topology_ref_history, port,
1651 static __always_inline void
1652 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1653 enum drm_dp_mst_topology_ref_type type)
1655 __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1658 static __always_inline void
1659 save_port_topology_ref(struct drm_dp_mst_port *port,
1660 enum drm_dp_mst_topology_ref_type type)
1662 __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1666 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1668 mutex_lock(&mgr->topology_ref_history_lock);
1672 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1674 mutex_unlock(&mgr->topology_ref_history_lock);
1678 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1680 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1682 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1684 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1685 #define save_mstb_topology_ref(mstb, type)
1686 #define save_port_topology_ref(port, type)
1689 struct drm_dp_mst_atomic_payload *
1690 drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
1691 struct drm_dp_mst_port *port)
1693 struct drm_dp_mst_atomic_payload *payload;
1695 list_for_each_entry(payload, &state->payloads, next)
1696 if (payload->port == port)
1701 EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
1703 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1705 struct drm_dp_mst_branch *mstb =
1706 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1707 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1709 drm_dp_mst_dump_mstb_topology_history(mstb);
1711 INIT_LIST_HEAD(&mstb->destroy_next);
1714 * This can get called under mgr->mutex, so we need to perform the
1715 * actual destruction of the mstb in another worker
1717 mutex_lock(&mgr->delayed_destroy_lock);
1718 list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1719 mutex_unlock(&mgr->delayed_destroy_lock);
1720 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1724 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1725 * branch device unless it's zero
1726 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1728 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1729 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1730 * reached 0). Holding a topology reference implies that a malloc reference
1731 * will be held to @mstb as long as the user holds the topology reference.
1733 * Care should be taken to ensure that the user has at least one malloc
1734 * reference to @mstb. If you already have a topology reference to @mstb, you
1735 * should use drm_dp_mst_topology_get_mstb() instead.
1738 * drm_dp_mst_topology_get_mstb()
1739 * drm_dp_mst_topology_put_mstb()
1742 * * 1: A topology reference was grabbed successfully
1743 * * 0: @port is no longer in the topology, no reference was grabbed
1745 static int __must_check
1746 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1750 topology_ref_history_lock(mstb->mgr);
1751 ret = kref_get_unless_zero(&mstb->topology_kref);
1753 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1754 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1757 topology_ref_history_unlock(mstb->mgr);
1763 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1765 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1767 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1768 * not it's already reached 0. This is only valid to use in scenarios where
1769 * you are already guaranteed to have at least one active topology reference
1770 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1773 * drm_dp_mst_topology_try_get_mstb()
1774 * drm_dp_mst_topology_put_mstb()
1776 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1778 topology_ref_history_lock(mstb->mgr);
1780 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1781 WARN_ON(kref_read(&mstb->topology_kref) == 0);
1782 kref_get(&mstb->topology_kref);
1783 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1785 topology_ref_history_unlock(mstb->mgr);
1789 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1791 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1793 * Releases a topology reference from @mstb by decrementing
1794 * &drm_dp_mst_branch.topology_kref.
1797 * drm_dp_mst_topology_try_get_mstb()
1798 * drm_dp_mst_topology_get_mstb()
1801 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1803 topology_ref_history_lock(mstb->mgr);
1805 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1806 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1808 topology_ref_history_unlock(mstb->mgr);
1809 kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1812 static void drm_dp_destroy_port(struct kref *kref)
1814 struct drm_dp_mst_port *port =
1815 container_of(kref, struct drm_dp_mst_port, topology_kref);
1816 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1818 drm_dp_mst_dump_port_topology_history(port);
1820 /* There's nothing that needs locking to destroy an input port yet */
1822 drm_dp_mst_put_port_malloc(port);
1826 drm_edid_free(port->cached_edid);
1829 * we can't destroy the connector here, as we might be holding the
1830 * mode_config.mutex from an EDID retrieval
1832 mutex_lock(&mgr->delayed_destroy_lock);
1833 list_add(&port->next, &mgr->destroy_port_list);
1834 mutex_unlock(&mgr->delayed_destroy_lock);
1835 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1839 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1840 * port unless it's zero
1841 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1843 * Attempts to grab a topology reference to @port, if it hasn't yet been
1844 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1845 * 0). Holding a topology reference implies that a malloc reference will be
1846 * held to @port as long as the user holds the topology reference.
1848 * Care should be taken to ensure that the user has at least one malloc
1849 * reference to @port. If you already have a topology reference to @port, you
1850 * should use drm_dp_mst_topology_get_port() instead.
1853 * drm_dp_mst_topology_get_port()
1854 * drm_dp_mst_topology_put_port()
1857 * * 1: A topology reference was grabbed successfully
1858 * * 0: @port is no longer in the topology, no reference was grabbed
1860 static int __must_check
1861 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1865 topology_ref_history_lock(port->mgr);
1866 ret = kref_get_unless_zero(&port->topology_kref);
1868 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1869 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1872 topology_ref_history_unlock(port->mgr);
1877 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1878 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1880 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1881 * not it's already reached 0. This is only valid to use in scenarios where
1882 * you are already guaranteed to have at least one active topology reference
1883 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1886 * drm_dp_mst_topology_try_get_port()
1887 * drm_dp_mst_topology_put_port()
1889 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1891 topology_ref_history_lock(port->mgr);
1893 WARN_ON(kref_read(&port->topology_kref) == 0);
1894 kref_get(&port->topology_kref);
1895 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1896 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1898 topology_ref_history_unlock(port->mgr);
1902 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1903 * @port: The &struct drm_dp_mst_port to release the topology reference from
1905 * Releases a topology reference from @port by decrementing
1906 * &drm_dp_mst_port.topology_kref.
1909 * drm_dp_mst_topology_try_get_port()
1910 * drm_dp_mst_topology_get_port()
1912 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1914 topology_ref_history_lock(port->mgr);
1916 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1917 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1919 topology_ref_history_unlock(port->mgr);
1920 kref_put(&port->topology_kref, drm_dp_destroy_port);
1923 static struct drm_dp_mst_branch *
1924 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1925 struct drm_dp_mst_branch *to_find)
1927 struct drm_dp_mst_port *port;
1928 struct drm_dp_mst_branch *rmstb;
1930 if (to_find == mstb)
1933 list_for_each_entry(port, &mstb->ports, next) {
1935 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1936 port->mstb, to_find);
1944 static struct drm_dp_mst_branch *
1945 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1946 struct drm_dp_mst_branch *mstb)
1948 struct drm_dp_mst_branch *rmstb = NULL;
1950 mutex_lock(&mgr->lock);
1951 if (mgr->mst_primary) {
1952 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1953 mgr->mst_primary, mstb);
1955 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1958 mutex_unlock(&mgr->lock);
1962 static struct drm_dp_mst_port *
1963 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1964 struct drm_dp_mst_port *to_find)
1966 struct drm_dp_mst_port *port, *mport;
1968 list_for_each_entry(port, &mstb->ports, next) {
1969 if (port == to_find)
1973 mport = drm_dp_mst_topology_get_port_validated_locked(
1974 port->mstb, to_find);
1982 static struct drm_dp_mst_port *
1983 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1984 struct drm_dp_mst_port *port)
1986 struct drm_dp_mst_port *rport = NULL;
1988 mutex_lock(&mgr->lock);
1989 if (mgr->mst_primary) {
1990 rport = drm_dp_mst_topology_get_port_validated_locked(
1991 mgr->mst_primary, port);
1993 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1996 mutex_unlock(&mgr->lock);
2000 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2002 struct drm_dp_mst_port *port;
2005 list_for_each_entry(port, &mstb->ports, next) {
2006 if (port->port_num == port_num) {
2007 ret = drm_dp_mst_topology_try_get_port(port);
2008 return ret ? port : NULL;
2016 * calculate a new RAD for this MST branch device
2017 * if parent has an LCT of 2 then it has 1 nibble of RAD,
2018 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2020 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2023 int parent_lct = port->parent->lct;
2025 int idx = (parent_lct - 1) / 2;
2027 if (parent_lct > 1) {
2028 memcpy(rad, port->parent->rad, idx + 1);
2029 shift = (parent_lct % 2) ? 4 : 0;
2033 rad[idx] |= port->port_num << shift;
2034 return parent_lct + 1;
2037 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2040 case DP_PEER_DEVICE_DP_LEGACY_CONV:
2041 case DP_PEER_DEVICE_SST_SINK:
2043 case DP_PEER_DEVICE_MST_BRANCHING:
2044 /* For sst branch device */
2054 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2057 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2058 struct drm_dp_mst_branch *mstb;
2062 if (port->pdt == new_pdt && port->mcs == new_mcs)
2065 /* Teardown the old pdt, if there is one */
2066 if (port->pdt != DP_PEER_DEVICE_NONE) {
2067 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2069 * If the new PDT would also have an i2c bus,
2070 * don't bother with reregistering it
2072 if (new_pdt != DP_PEER_DEVICE_NONE &&
2073 drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2074 port->pdt = new_pdt;
2075 port->mcs = new_mcs;
2079 /* remove i2c over sideband */
2080 drm_dp_mst_unregister_i2c_bus(port);
2082 mutex_lock(&mgr->lock);
2083 drm_dp_mst_topology_put_mstb(port->mstb);
2085 mutex_unlock(&mgr->lock);
2089 port->pdt = new_pdt;
2090 port->mcs = new_mcs;
2092 if (port->pdt != DP_PEER_DEVICE_NONE) {
2093 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2094 /* add i2c over sideband */
2095 ret = drm_dp_mst_register_i2c_bus(port);
2097 lct = drm_dp_calculate_rad(port, rad);
2098 mstb = drm_dp_add_mst_branch_device(lct, rad);
2101 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2105 mutex_lock(&mgr->lock);
2107 mstb->mgr = port->mgr;
2108 mstb->port_parent = port;
2111 * Make sure this port's memory allocation stays
2112 * around until its child MSTB releases it
2114 drm_dp_mst_get_port_malloc(port);
2115 mutex_unlock(&mgr->lock);
2117 /* And make sure we send a link address for this */
2124 port->pdt = DP_PEER_DEVICE_NONE;
2129 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2130 * @aux: Fake sideband AUX CH
2131 * @offset: address of the (first) register to read
2132 * @buffer: buffer to store the register values
2133 * @size: number of bytes in @buffer
2135 * Performs the same functionality for remote devices via
2136 * sideband messaging as drm_dp_dpcd_read() does for local
2137 * devices via actual AUX CH.
2139 * Return: Number of bytes read, or negative error code on failure.
2141 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2142 unsigned int offset, void *buffer, size_t size)
2144 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2147 return drm_dp_send_dpcd_read(port->mgr, port,
2148 offset, size, buffer);
2152 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2153 * @aux: Fake sideband AUX CH
2154 * @offset: address of the (first) register to write
2155 * @buffer: buffer containing the values to write
2156 * @size: number of bytes in @buffer
2158 * Performs the same functionality for remote devices via
2159 * sideband messaging as drm_dp_dpcd_write() does for local
2160 * devices via actual AUX CH.
2162 * Return: number of bytes written on success, negative error code on failure.
2164 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2165 unsigned int offset, void *buffer, size_t size)
2167 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2170 return drm_dp_send_dpcd_write(port->mgr, port,
2171 offset, size, buffer);
2174 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2178 memcpy(mstb->guid, guid, 16);
2180 if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2181 if (mstb->port_parent) {
2182 ret = drm_dp_send_dpcd_write(mstb->mgr,
2184 DP_GUID, 16, mstb->guid);
2186 ret = drm_dp_dpcd_write(mstb->mgr->aux,
2187 DP_GUID, mstb->guid, 16);
2191 if (ret < 16 && ret > 0)
2194 return ret == 16 ? 0 : ret;
2197 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2200 size_t proppath_size)
2205 snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2206 for (i = 0; i < (mstb->lct - 1); i++) {
2207 int shift = (i % 2) ? 0 : 4;
2208 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2210 snprintf(temp, sizeof(temp), "-%d", port_num);
2211 strlcat(proppath, temp, proppath_size);
2213 snprintf(temp, sizeof(temp), "-%d", pnum);
2214 strlcat(proppath, temp, proppath_size);
2218 * drm_dp_mst_connector_late_register() - Late MST connector registration
2219 * @connector: The MST connector
2220 * @port: The MST port for this connector
2222 * Helper to register the remote aux device for this MST port. Drivers should
2223 * call this from their mst connector's late_register hook to enable MST aux
2226 * Return: 0 on success, negative error code on failure.
2228 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2229 struct drm_dp_mst_port *port)
2231 drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2232 port->aux.name, connector->kdev->kobj.name);
2234 port->aux.dev = connector->kdev;
2235 return drm_dp_aux_register_devnode(&port->aux);
2237 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2240 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2241 * @connector: The MST connector
2242 * @port: The MST port for this connector
2244 * Helper to unregister the remote aux device for this MST port, registered by
2245 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2246 * connector's early_unregister hook.
2248 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2249 struct drm_dp_mst_port *port)
2251 drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2252 port->aux.name, connector->kdev->kobj.name);
2253 drm_dp_aux_unregister_devnode(&port->aux);
2255 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2258 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2259 struct drm_dp_mst_port *port)
2261 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2265 build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2266 port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2267 if (!port->connector) {
2272 if (port->pdt != DP_PEER_DEVICE_NONE &&
2273 drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2274 port->port_num >= DP_MST_LOGICAL_PORT_0)
2275 port->cached_edid = drm_edid_read_ddc(port->connector,
2278 drm_connector_register(port->connector);
2282 drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2286 * Drop a topology reference, and unlink the port from the in-memory topology
2290 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2291 struct drm_dp_mst_port *port)
2293 mutex_lock(&mgr->lock);
2294 port->parent->num_ports--;
2295 list_del(&port->next);
2296 mutex_unlock(&mgr->lock);
2297 drm_dp_mst_topology_put_port(port);
2300 static struct drm_dp_mst_port *
2301 drm_dp_mst_add_port(struct drm_device *dev,
2302 struct drm_dp_mst_topology_mgr *mgr,
2303 struct drm_dp_mst_branch *mstb, u8 port_number)
2305 struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2310 kref_init(&port->topology_kref);
2311 kref_init(&port->malloc_kref);
2312 port->parent = mstb;
2313 port->port_num = port_number;
2315 port->aux.name = "DPMST";
2316 port->aux.dev = dev->dev;
2317 port->aux.is_remote = true;
2319 /* initialize the MST downstream port's AUX crc work queue */
2320 port->aux.drm_dev = dev;
2321 drm_dp_remote_aux_init(&port->aux);
2324 * Make sure the memory allocation for our parent branch stays
2325 * around until our own memory allocation is released
2327 drm_dp_mst_get_mstb_malloc(mstb);
2333 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2334 struct drm_device *dev,
2335 struct drm_dp_link_addr_reply_port *port_msg)
2337 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2338 struct drm_dp_mst_port *port;
2339 int old_ddps = 0, ret;
2340 u8 new_pdt = DP_PEER_DEVICE_NONE;
2342 bool created = false, send_link_addr = false, changed = false;
2344 port = drm_dp_get_port(mstb, port_msg->port_number);
2346 port = drm_dp_mst_add_port(dev, mgr, mstb,
2347 port_msg->port_number);
2352 } else if (!port->input && port_msg->input_port && port->connector) {
2353 /* Since port->connector can't be changed here, we create a
2354 * new port if input_port changes from 0 to 1
2356 drm_dp_mst_topology_unlink_port(mgr, port);
2357 drm_dp_mst_topology_put_port(port);
2358 port = drm_dp_mst_add_port(dev, mgr, mstb,
2359 port_msg->port_number);
2364 } else if (port->input && !port_msg->input_port) {
2366 } else if (port->connector) {
2367 /* We're updating a port that's exposed to userspace, so do it
2370 drm_modeset_lock(&mgr->base.lock, NULL);
2372 old_ddps = port->ddps;
2373 changed = port->ddps != port_msg->ddps ||
2375 (port->ldps != port_msg->legacy_device_plug_status ||
2376 port->dpcd_rev != port_msg->dpcd_revision ||
2377 port->mcs != port_msg->mcs ||
2378 port->pdt != port_msg->peer_device_type ||
2379 port->num_sdp_stream_sinks !=
2380 port_msg->num_sdp_stream_sinks));
2383 port->input = port_msg->input_port;
2385 new_pdt = port_msg->peer_device_type;
2386 new_mcs = port_msg->mcs;
2387 port->ddps = port_msg->ddps;
2388 port->ldps = port_msg->legacy_device_plug_status;
2389 port->dpcd_rev = port_msg->dpcd_revision;
2390 port->num_sdp_streams = port_msg->num_sdp_streams;
2391 port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2393 /* manage mstb port lists with mgr lock - take a reference
2396 mutex_lock(&mgr->lock);
2397 drm_dp_mst_topology_get_port(port);
2398 list_add(&port->next, &mstb->ports);
2400 mutex_unlock(&mgr->lock);
2404 * Reprobe PBN caps on both hotplug, and when re-probing the link
2405 * for our parent mstb
2407 if (old_ddps != port->ddps || !created) {
2408 if (port->ddps && !port->input) {
2409 ret = drm_dp_send_enum_path_resources(mgr, mstb,
2418 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2420 send_link_addr = true;
2421 } else if (ret < 0) {
2422 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2427 * If this port wasn't just created, then we're reprobing because
2428 * we're coming out of suspend. In this case, always resend the link
2429 * address if there's an MSTB on this port
2431 if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2433 send_link_addr = true;
2435 if (port->connector)
2436 drm_modeset_unlock(&mgr->base.lock);
2437 else if (!port->input)
2438 drm_dp_mst_port_add_connector(mstb, port);
2440 if (send_link_addr && port->mstb) {
2441 ret = drm_dp_send_link_address(mgr, port->mstb);
2442 if (ret == 1) /* MSTB below us changed */
2448 /* put reference to this port */
2449 drm_dp_mst_topology_put_port(port);
2453 drm_dp_mst_topology_unlink_port(mgr, port);
2454 if (port->connector)
2455 drm_modeset_unlock(&mgr->base.lock);
2457 drm_dp_mst_topology_put_port(port);
2462 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2463 struct drm_dp_connection_status_notify *conn_stat)
2465 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2466 struct drm_dp_mst_port *port;
2470 bool dowork = false, create_connector = false;
2472 port = drm_dp_get_port(mstb, conn_stat->port_number);
2476 if (port->connector) {
2477 if (!port->input && conn_stat->input_port) {
2479 * We can't remove a connector from an already exposed
2480 * port, so just throw the port out and make sure we
2481 * reprobe the link address of it's parent MSTB
2483 drm_dp_mst_topology_unlink_port(mgr, port);
2484 mstb->link_address_sent = false;
2489 /* Locking is only needed if the port's exposed to userspace */
2490 drm_modeset_lock(&mgr->base.lock, NULL);
2491 } else if (port->input && !conn_stat->input_port) {
2492 create_connector = true;
2493 /* Reprobe link address so we get num_sdp_streams */
2494 mstb->link_address_sent = false;
2498 old_ddps = port->ddps;
2499 port->input = conn_stat->input_port;
2500 port->ldps = conn_stat->legacy_device_plug_status;
2501 port->ddps = conn_stat->displayport_device_plug_status;
2503 if (old_ddps != port->ddps) {
2504 if (port->ddps && !port->input)
2505 drm_dp_send_enum_path_resources(mgr, mstb, port);
2510 new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2511 new_mcs = conn_stat->message_capability_status;
2512 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2515 } else if (ret < 0) {
2516 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2520 if (port->connector)
2521 drm_modeset_unlock(&mgr->base.lock);
2522 else if (create_connector)
2523 drm_dp_mst_port_add_connector(mstb, port);
2526 drm_dp_mst_topology_put_port(port);
2530 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2533 struct drm_dp_mst_branch *mstb;
2534 struct drm_dp_mst_port *port;
2536 /* find the port by iterating down */
2538 mutex_lock(&mgr->lock);
2539 mstb = mgr->mst_primary;
2544 for (i = 0; i < lct - 1; i++) {
2545 int shift = (i % 2) ? 0 : 4;
2546 int port_num = (rad[i / 2] >> shift) & 0xf;
2548 list_for_each_entry(port, &mstb->ports, next) {
2549 if (port->port_num == port_num) {
2553 "failed to lookup MSTB with lct %d, rad %02x\n",
2562 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2566 mutex_unlock(&mgr->lock);
2570 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2571 struct drm_dp_mst_branch *mstb,
2572 const uint8_t *guid)
2574 struct drm_dp_mst_branch *found_mstb;
2575 struct drm_dp_mst_port *port;
2580 if (memcmp(mstb->guid, guid, 16) == 0)
2584 list_for_each_entry(port, &mstb->ports, next) {
2585 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2594 static struct drm_dp_mst_branch *
2595 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2596 const uint8_t *guid)
2598 struct drm_dp_mst_branch *mstb;
2601 /* find the port by iterating down */
2602 mutex_lock(&mgr->lock);
2604 mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2606 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2611 mutex_unlock(&mgr->lock);
2615 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2616 struct drm_dp_mst_branch *mstb)
2618 struct drm_dp_mst_port *port;
2620 bool changed = false;
2622 if (!mstb->link_address_sent) {
2623 ret = drm_dp_send_link_address(mgr, mstb);
2630 list_for_each_entry(port, &mstb->ports, next) {
2631 if (port->input || !port->ddps || !port->mstb)
2634 ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2644 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2646 struct drm_dp_mst_topology_mgr *mgr =
2647 container_of(work, struct drm_dp_mst_topology_mgr, work);
2648 struct drm_device *dev = mgr->dev;
2649 struct drm_dp_mst_branch *mstb;
2651 bool clear_payload_id_table;
2653 mutex_lock(&mgr->probe_lock);
2655 mutex_lock(&mgr->lock);
2656 clear_payload_id_table = !mgr->payload_id_table_cleared;
2657 mgr->payload_id_table_cleared = true;
2659 mstb = mgr->mst_primary;
2661 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2665 mutex_unlock(&mgr->lock);
2667 mutex_unlock(&mgr->probe_lock);
2672 * Certain branch devices seem to incorrectly report an available_pbn
2673 * of 0 on downstream sinks, even after clearing the
2674 * DP_PAYLOAD_ALLOCATE_* registers in
2675 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2676 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2677 * things work again.
2679 if (clear_payload_id_table) {
2680 drm_dbg_kms(dev, "Clearing payload ID table\n");
2681 drm_dp_send_clear_payload_id_table(mgr, mstb);
2684 ret = drm_dp_check_and_send_link_address(mgr, mstb);
2685 drm_dp_mst_topology_put_mstb(mstb);
2687 mutex_unlock(&mgr->probe_lock);
2689 drm_kms_helper_hotplug_event(dev);
2692 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2697 if (memchr_inv(guid, 0, 16))
2700 salt = get_jiffies_64();
2702 memcpy(&guid[0], &salt, sizeof(u64));
2703 memcpy(&guid[8], &salt, sizeof(u64));
2708 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2709 u8 port_num, u32 offset, u8 num_bytes)
2711 struct drm_dp_sideband_msg_req_body req;
2713 req.req_type = DP_REMOTE_DPCD_READ;
2714 req.u.dpcd_read.port_number = port_num;
2715 req.u.dpcd_read.dpcd_address = offset;
2716 req.u.dpcd_read.num_bytes = num_bytes;
2717 drm_dp_encode_sideband_req(&req, msg);
2720 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2721 bool up, u8 *msg, int len)
2724 int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2725 int tosend, total, offset;
2732 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2734 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2737 if (ret != tosend) {
2738 if (ret == -EIO && retries < 5) {
2742 drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2748 } while (total > 0);
2752 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2753 struct drm_dp_sideband_msg_tx *txmsg)
2755 struct drm_dp_mst_branch *mstb = txmsg->dst;
2758 req_type = txmsg->msg[0] & 0x7f;
2759 if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2760 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2761 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2765 hdr->path_msg = txmsg->path_msg;
2766 if (hdr->broadcast) {
2770 hdr->lct = mstb->lct;
2771 hdr->lcr = mstb->lct - 1;
2774 memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2779 * process a single block of the next message in the sideband queue
2781 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2782 struct drm_dp_sideband_msg_tx *txmsg,
2786 struct drm_dp_sideband_msg_hdr hdr;
2787 int len, space, idx, tosend;
2790 if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2793 memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2795 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2796 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2798 /* make hdr from dst mst */
2799 ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2803 /* amount left to send in this message */
2804 len = txmsg->cur_len - txmsg->cur_offset;
2806 /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2807 space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2809 tosend = min(len, space);
2810 if (len == txmsg->cur_len)
2816 hdr.msg_len = tosend + 1;
2817 drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2818 memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2819 /* add crc at end */
2820 drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2823 ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2825 if (drm_debug_enabled(DRM_UT_DP)) {
2826 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2828 drm_printf(&p, "sideband msg failed to send\n");
2829 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2834 txmsg->cur_offset += tosend;
2835 if (txmsg->cur_offset == txmsg->cur_len) {
2836 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2842 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2844 struct drm_dp_sideband_msg_tx *txmsg;
2847 WARN_ON(!mutex_is_locked(&mgr->qlock));
2849 /* construct a chunk from the first msg in the tx_msg queue */
2850 if (list_empty(&mgr->tx_msg_downq))
2853 txmsg = list_first_entry(&mgr->tx_msg_downq,
2854 struct drm_dp_sideband_msg_tx, next);
2855 ret = process_single_tx_qlock(mgr, txmsg, false);
2857 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2858 list_del(&txmsg->next);
2859 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2860 wake_up_all(&mgr->tx_waitq);
2864 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2865 struct drm_dp_sideband_msg_tx *txmsg)
2867 mutex_lock(&mgr->qlock);
2868 list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2870 if (drm_debug_enabled(DRM_UT_DP)) {
2871 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2873 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2876 if (list_is_singular(&mgr->tx_msg_downq))
2877 process_single_down_tx_qlock(mgr);
2878 mutex_unlock(&mgr->qlock);
2882 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2883 struct drm_dp_link_address_ack_reply *reply)
2885 struct drm_dp_link_addr_reply_port *port_reply;
2888 for (i = 0; i < reply->nports; i++) {
2889 port_reply = &reply->ports[i];
2890 drm_dbg_kms(mgr->dev,
2891 "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2893 port_reply->input_port,
2894 port_reply->peer_device_type,
2895 port_reply->port_number,
2896 port_reply->dpcd_revision,
2899 port_reply->legacy_device_plug_status,
2900 port_reply->num_sdp_streams,
2901 port_reply->num_sdp_stream_sinks);
2905 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2906 struct drm_dp_mst_branch *mstb)
2908 struct drm_dp_sideband_msg_tx *txmsg;
2909 struct drm_dp_link_address_ack_reply *reply;
2910 struct drm_dp_mst_port *port, *tmp;
2911 int i, ret, port_mask = 0;
2912 bool changed = false;
2914 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2919 build_link_address(txmsg);
2921 mstb->link_address_sent = true;
2922 drm_dp_queue_down_tx(mgr, txmsg);
2924 /* FIXME: Actually do some real error handling here */
2925 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2927 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2930 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2931 drm_err(mgr->dev, "link address NAK received\n");
2936 reply = &txmsg->reply.u.link_addr;
2937 drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2938 drm_dp_dump_link_address(mgr, reply);
2940 ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2944 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2945 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2949 for (i = 0; i < reply->nports; i++) {
2950 port_mask |= BIT(reply->ports[i].port_number);
2951 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2959 /* Prune any ports that are currently a part of mstb in our in-memory
2960 * topology, but were not seen in this link address. Usually this
2961 * means that they were removed while the topology was out of sync,
2962 * e.g. during suspend/resume
2964 mutex_lock(&mgr->lock);
2965 list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2966 if (port_mask & BIT(port->port_num))
2969 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
2971 list_del(&port->next);
2972 drm_dp_mst_topology_put_port(port);
2975 mutex_unlock(&mgr->lock);
2979 mstb->link_address_sent = false;
2981 return ret < 0 ? ret : changed;
2985 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2986 struct drm_dp_mst_branch *mstb)
2988 struct drm_dp_sideband_msg_tx *txmsg;
2991 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2996 build_clear_payload_id_table(txmsg);
2998 drm_dp_queue_down_tx(mgr, txmsg);
3000 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3001 if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3002 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3008 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3009 struct drm_dp_mst_branch *mstb,
3010 struct drm_dp_mst_port *port)
3012 struct drm_dp_enum_path_resources_ack_reply *path_res;
3013 struct drm_dp_sideband_msg_tx *txmsg;
3016 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3021 build_enum_path_resources(txmsg, port->port_num);
3023 drm_dp_queue_down_tx(mgr, txmsg);
3025 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3028 path_res = &txmsg->reply.u.path_resources;
3030 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3031 drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3033 if (port->port_num != path_res->port_number)
3034 DRM_ERROR("got incorrect port in response\n");
3036 drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3037 path_res->port_number,
3038 path_res->full_payload_bw_number,
3039 path_res->avail_payload_bw_number);
3042 * If something changed, make sure we send a
3045 if (port->full_pbn != path_res->full_payload_bw_number ||
3046 port->fec_capable != path_res->fec_capable)
3049 port->full_pbn = path_res->full_payload_bw_number;
3050 port->fec_capable = path_res->fec_capable;
3058 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3060 if (!mstb->port_parent)
3063 if (mstb->port_parent->mstb != mstb)
3064 return mstb->port_parent;
3066 return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3070 * Searches upwards in the topology starting from mstb to try to find the
3071 * closest available parent of mstb that's still connected to the rest of the
3072 * topology. This can be used in order to perform operations like releasing
3073 * payloads, where the branch device which owned the payload may no longer be
3074 * around and thus would require that the payload on the last living relative
3077 static struct drm_dp_mst_branch *
3078 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3079 struct drm_dp_mst_branch *mstb,
3082 struct drm_dp_mst_branch *rmstb = NULL;
3083 struct drm_dp_mst_port *found_port;
3085 mutex_lock(&mgr->lock);
3086 if (!mgr->mst_primary)
3090 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3094 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3095 rmstb = found_port->parent;
3096 *port_num = found_port->port_num;
3098 /* Search again, starting from this parent */
3099 mstb = found_port->parent;
3103 mutex_unlock(&mgr->lock);
3107 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3108 struct drm_dp_mst_port *port,
3112 struct drm_dp_sideband_msg_tx *txmsg;
3113 struct drm_dp_mst_branch *mstb;
3115 u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3118 port_num = port->port_num;
3119 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3121 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3129 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3135 for (i = 0; i < port->num_sdp_streams; i++)
3139 build_allocate_payload(txmsg, port_num,
3141 pbn, port->num_sdp_streams, sinks);
3143 drm_dp_queue_down_tx(mgr, txmsg);
3146 * FIXME: there is a small chance that between getting the last
3147 * connected mstb and sending the payload message, the last connected
3148 * mstb could also be removed from the topology. In the future, this
3149 * needs to be fixed by restarting the
3150 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3151 * timeout if the topology is still connected to the system.
3153 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3155 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3162 drm_dp_mst_topology_put_mstb(mstb);
3166 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3167 struct drm_dp_mst_port *port, bool power_up)
3169 struct drm_dp_sideband_msg_tx *txmsg;
3172 port = drm_dp_mst_topology_get_port_validated(mgr, port);
3176 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3178 drm_dp_mst_topology_put_port(port);
3182 txmsg->dst = port->parent;
3183 build_power_updown_phy(txmsg, port->port_num, power_up);
3184 drm_dp_queue_down_tx(mgr, txmsg);
3186 ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3188 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3194 drm_dp_mst_topology_put_port(port);
3198 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3200 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3201 struct drm_dp_mst_port *port,
3202 struct drm_dp_query_stream_enc_status_ack_reply *status)
3204 struct drm_dp_mst_topology_state *state;
3205 struct drm_dp_mst_atomic_payload *payload;
3206 struct drm_dp_sideband_msg_tx *txmsg;
3210 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3214 port = drm_dp_mst_topology_get_port_validated(mgr, port);
3220 get_random_bytes(nonce, sizeof(nonce));
3222 drm_modeset_lock(&mgr->base.lock, NULL);
3223 state = to_drm_dp_mst_topology_state(mgr->base.state);
3224 payload = drm_atomic_get_mst_payload_state(state, port);
3227 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3228 * transaction at the MST Branch device directly connected to the
3231 txmsg->dst = mgr->mst_primary;
3233 build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
3235 drm_dp_queue_down_tx(mgr, txmsg);
3237 ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3240 } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3241 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3247 memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3250 drm_modeset_unlock(&mgr->base.lock);
3251 drm_dp_mst_topology_put_port(port);
3256 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3258 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3259 struct drm_dp_mst_atomic_payload *payload)
3261 return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
3262 payload->time_slots);
3265 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3266 struct drm_dp_mst_atomic_payload *payload)
3269 struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3274 ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
3275 drm_dp_mst_topology_put_port(port);
3279 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3280 struct drm_dp_mst_topology_state *mst_state,
3281 struct drm_dp_mst_atomic_payload *payload)
3283 drm_dbg_kms(mgr->dev, "\n");
3285 /* it's okay for these to fail */
3286 drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
3287 drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
3293 * drm_dp_add_payload_part1() - Execute payload update part 1
3294 * @mgr: Manager to use.
3295 * @mst_state: The MST atomic state
3296 * @payload: The payload to write
3298 * Determines the starting time slot for the given payload, and programs the VCPI for this payload
3299 * into hardware. After calling this, the driver should generate ACT and payload packets.
3301 * Returns: 0 on success, error code on failure. In the event that this fails,
3302 * @payload.vc_start_slot will also be set to -1.
3304 int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3305 struct drm_dp_mst_topology_state *mst_state,
3306 struct drm_dp_mst_atomic_payload *payload)
3308 struct drm_dp_mst_port *port;
3311 port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3313 drm_dbg_kms(mgr->dev,
3314 "VCPI %d for port %p not in topology, not creating a payload\n",
3315 payload->vcpi, payload->port);
3316 payload->vc_start_slot = -1;
3320 if (mgr->payload_count == 0)
3321 mgr->next_start_slot = mst_state->start_slot;
3323 payload->vc_start_slot = mgr->next_start_slot;
3325 ret = drm_dp_create_payload_step1(mgr, payload);
3326 drm_dp_mst_topology_put_port(port);
3328 drm_warn(mgr->dev, "Failed to create MST payload for port %p: %d\n",
3329 payload->port, ret);
3330 payload->vc_start_slot = -1;
3334 mgr->payload_count++;
3335 mgr->next_start_slot += payload->time_slots;
3339 EXPORT_SYMBOL(drm_dp_add_payload_part1);
3342 * drm_dp_remove_payload() - Remove an MST payload
3343 * @mgr: Manager to use.
3344 * @mst_state: The MST atomic state
3345 * @old_payload: The payload with its old state
3346 * @new_payload: The payload to write
3348 * Removes a payload from an MST topology if it was successfully assigned a start slot. Also updates
3349 * the starting time slots of all other payloads which would have been shifted towards the start of
3350 * the VC table as a result. After calling this, the driver should generate ACT and payload packets.
3352 void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
3353 struct drm_dp_mst_topology_state *mst_state,
3354 const struct drm_dp_mst_atomic_payload *old_payload,
3355 struct drm_dp_mst_atomic_payload *new_payload)
3357 struct drm_dp_mst_atomic_payload *pos;
3358 bool send_remove = false;
3360 /* We failed to make the payload, so nothing to do */
3361 if (new_payload->vc_start_slot == -1)
3364 mutex_lock(&mgr->lock);
3365 send_remove = drm_dp_mst_port_downstream_of_branch(new_payload->port, mgr->mst_primary);
3366 mutex_unlock(&mgr->lock);
3369 drm_dp_destroy_payload_step1(mgr, mst_state, new_payload);
3371 drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n",
3374 list_for_each_entry(pos, &mst_state->payloads, next) {
3375 if (pos != new_payload && pos->vc_start_slot > new_payload->vc_start_slot)
3376 pos->vc_start_slot -= old_payload->time_slots;
3378 new_payload->vc_start_slot = -1;
3380 mgr->payload_count--;
3381 mgr->next_start_slot -= old_payload->time_slots;
3383 if (new_payload->delete)
3384 drm_dp_mst_put_port_malloc(new_payload->port);
3386 EXPORT_SYMBOL(drm_dp_remove_payload);
3389 * drm_dp_add_payload_part2() - Execute payload update part 2
3390 * @mgr: Manager to use.
3391 * @state: The global atomic state
3392 * @payload: The payload to update
3394 * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
3395 * function will send the sideband messages to finish allocating this payload.
3397 * Returns: 0 on success, negative error code on failure.
3399 int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3400 struct drm_atomic_state *state,
3401 struct drm_dp_mst_atomic_payload *payload)
3405 /* Skip failed payloads */
3406 if (payload->vc_start_slot == -1) {
3407 drm_dbg_kms(mgr->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
3408 payload->port->connector->name);
3412 ret = drm_dp_create_payload_step2(mgr, payload);
3414 if (!payload->delete)
3415 drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
3416 payload->port, ret);
3418 drm_dbg_kms(mgr->dev, "Step 2 of removing MST payload for %p failed: %d\n",
3419 payload->port, ret);
3424 EXPORT_SYMBOL(drm_dp_add_payload_part2);
3426 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3427 struct drm_dp_mst_port *port,
3428 int offset, int size, u8 *bytes)
3431 struct drm_dp_sideband_msg_tx *txmsg;
3432 struct drm_dp_mst_branch *mstb;
3434 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3438 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3444 build_dpcd_read(txmsg, port->port_num, offset, size);
3445 txmsg->dst = port->parent;
3447 drm_dp_queue_down_tx(mgr, txmsg);
3449 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3453 if (txmsg->reply.reply_type == 1) {
3454 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3455 mstb, port->port_num, offset, size);
3460 if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3465 ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3467 memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3472 drm_dp_mst_topology_put_mstb(mstb);
3477 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3478 struct drm_dp_mst_port *port,
3479 int offset, int size, u8 *bytes)
3482 struct drm_dp_sideband_msg_tx *txmsg;
3483 struct drm_dp_mst_branch *mstb;
3485 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3489 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3495 build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3498 drm_dp_queue_down_tx(mgr, txmsg);
3500 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3502 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3510 drm_dp_mst_topology_put_mstb(mstb);
3514 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3516 struct drm_dp_sideband_msg_reply_body reply;
3518 reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3519 reply.req_type = req_type;
3520 drm_dp_encode_sideband_reply(&reply, msg);
3524 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3525 struct drm_dp_mst_branch *mstb,
3526 int req_type, bool broadcast)
3528 struct drm_dp_sideband_msg_tx *txmsg;
3530 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3535 drm_dp_encode_up_ack_reply(txmsg, req_type);
3537 mutex_lock(&mgr->qlock);
3538 /* construct a chunk from the first msg in the tx_msg queue */
3539 process_single_tx_qlock(mgr, txmsg, true);
3540 mutex_unlock(&mgr->qlock);
3547 * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3548 * @mgr: The &drm_dp_mst_topology_mgr to use
3549 * @link_rate: link rate in 10kbits/s units
3550 * @link_lane_count: lane count
3552 * Calculate the total bandwidth of a MultiStream Transport link. The returned
3553 * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3554 * convert the number of PBNs required for a given stream to the number of
3555 * timeslots this stream requires in each MTP.
3557 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3558 int link_rate, int link_lane_count)
3560 if (link_rate == 0 || link_lane_count == 0)
3561 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3562 link_rate, link_lane_count);
3564 /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3565 return link_rate * link_lane_count / 54000;
3567 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3570 * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3571 * @aux: The DP AUX channel to use
3572 * @dpcd: A cached copy of the DPCD capabilities for this sink
3574 * Returns: %True if the sink supports MST, %false otherwise
3576 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3577 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3581 if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3584 if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3587 return mstm_cap & DP_MST_CAP;
3589 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3592 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3593 * @mgr: manager to set state for
3594 * @mst_state: true to enable MST on this connector - false to disable.
3596 * This is called by the driver when it detects an MST capable device plugged
3597 * into a DP MST capable port, or when a DP MST capable device is unplugged.
3599 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3602 struct drm_dp_mst_branch *mstb = NULL;
3604 mutex_lock(&mgr->lock);
3605 if (mst_state == mgr->mst_state)
3608 mgr->mst_state = mst_state;
3609 /* set the device into MST mode */
3611 WARN_ON(mgr->mst_primary);
3614 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3616 drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3617 mgr->aux->name, ret);
3621 /* add initial branch device at LCT 1 */
3622 mstb = drm_dp_add_mst_branch_device(1, NULL);
3629 /* give this the main reference */
3630 mgr->mst_primary = mstb;
3631 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3633 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3636 DP_UPSTREAM_IS_SRC);
3640 /* Write reset payload */
3641 drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
3643 queue_work(system_long_wq, &mgr->work);
3647 /* disable MST on the device */
3648 mstb = mgr->mst_primary;
3649 mgr->mst_primary = NULL;
3650 /* this can fail if the device is gone */
3651 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3653 mgr->payload_id_table_cleared = false;
3655 memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
3656 memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
3660 mutex_unlock(&mgr->lock);
3662 drm_dp_mst_topology_put_mstb(mstb);
3666 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3669 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3671 struct drm_dp_mst_port *port;
3673 /* The link address will need to be re-sent on resume */
3674 mstb->link_address_sent = false;
3676 list_for_each_entry(port, &mstb->ports, next)
3678 drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3682 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3683 * @mgr: manager to suspend
3685 * This function tells the MST device that we can't handle UP messages
3686 * anymore. This should stop it from sending any since we are suspended.
3688 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3690 mutex_lock(&mgr->lock);
3691 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3692 DP_MST_EN | DP_UPSTREAM_IS_SRC);
3693 mutex_unlock(&mgr->lock);
3694 flush_work(&mgr->up_req_work);
3695 flush_work(&mgr->work);
3696 flush_work(&mgr->delayed_destroy_work);
3698 mutex_lock(&mgr->lock);
3699 if (mgr->mst_state && mgr->mst_primary)
3700 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3701 mutex_unlock(&mgr->lock);
3703 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3706 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3707 * @mgr: manager to resume
3708 * @sync: whether or not to perform topology reprobing synchronously
3710 * This will fetch DPCD and see if the device is still there,
3711 * if it is, it will rewrite the MSTM control bits, and return.
3713 * If the device fails this returns -1, and the driver should do
3714 * a full MST reprobe, in case we were undocked.
3716 * During system resume (where it is assumed that the driver will be calling
3717 * drm_atomic_helper_resume()) this function should be called beforehand with
3718 * @sync set to true. In contexts like runtime resume where the driver is not
3719 * expected to be calling drm_atomic_helper_resume(), this function should be
3720 * called with @sync set to false in order to avoid deadlocking.
3722 * Returns: -1 if the MST topology was removed while we were suspended, 0
3725 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3731 mutex_lock(&mgr->lock);
3732 if (!mgr->mst_primary)
3735 if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3736 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3740 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3743 DP_UPSTREAM_IS_SRC);
3745 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3749 /* Some hubs forget their guids after they resume */
3750 ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3752 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3756 ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3758 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3763 * For the final step of resuming the topology, we need to bring the
3764 * state of our in-memory topology back into sync with reality. So,
3765 * restart the probing process as if we're probing a new hub
3767 queue_work(system_long_wq, &mgr->work);
3768 mutex_unlock(&mgr->lock);
3771 drm_dbg_kms(mgr->dev,
3772 "Waiting for link probe work to finish re-syncing topology...\n");
3773 flush_work(&mgr->work);
3779 mutex_unlock(&mgr->lock);
3782 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3785 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3786 struct drm_dp_mst_branch **mstb)
3790 int replylen, curreply;
3793 struct drm_dp_sideband_msg_hdr hdr;
3794 struct drm_dp_sideband_msg_rx *msg =
3795 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3796 int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3797 DP_SIDEBAND_MSG_DOWN_REP_BASE;
3802 len = min(mgr->max_dpcd_transaction_bytes, 16);
3803 ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3805 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3809 ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3811 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3812 1, replyblock, len, false);
3813 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3818 /* Caller is responsible for giving back this reference */
3819 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3821 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3826 if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3827 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3831 replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3832 ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3834 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3838 replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3840 while (replylen > 0) {
3841 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3842 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3845 drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3850 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3852 drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3862 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3864 struct drm_dp_sideband_msg_tx *txmsg;
3865 struct drm_dp_mst_branch *mstb = NULL;
3866 struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3868 if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3869 goto out_clear_reply;
3871 /* Multi-packet message transmission, don't clear the reply */
3872 if (!msg->have_eomt)
3875 /* find the message */
3876 mutex_lock(&mgr->qlock);
3877 txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3878 struct drm_dp_sideband_msg_tx, next);
3879 mutex_unlock(&mgr->qlock);
3881 /* Were we actually expecting a response, and from this mstb? */
3882 if (!txmsg || txmsg->dst != mstb) {
3883 struct drm_dp_sideband_msg_hdr *hdr;
3885 hdr = &msg->initial_hdr;
3886 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
3887 mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
3888 goto out_clear_reply;
3891 drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
3893 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3894 drm_dbg_kms(mgr->dev,
3895 "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3896 txmsg->reply.req_type,
3897 drm_dp_mst_req_type_str(txmsg->reply.req_type),
3898 txmsg->reply.u.nak.reason,
3899 drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3900 txmsg->reply.u.nak.nak_data);
3903 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3904 drm_dp_mst_topology_put_mstb(mstb);
3906 mutex_lock(&mgr->qlock);
3907 txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3908 list_del(&txmsg->next);
3909 mutex_unlock(&mgr->qlock);
3911 wake_up_all(&mgr->tx_waitq);
3916 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3919 drm_dp_mst_topology_put_mstb(mstb);
3925 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3926 struct drm_dp_pending_up_req *up_req)
3928 struct drm_dp_mst_branch *mstb = NULL;
3929 struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3930 struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3931 bool hotplug = false, dowork = false;
3933 if (hdr->broadcast) {
3934 const u8 *guid = NULL;
3936 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3937 guid = msg->u.conn_stat.guid;
3938 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3939 guid = msg->u.resource_stat.guid;
3942 mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3944 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3948 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
3952 /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3953 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3954 dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3958 drm_dp_mst_topology_put_mstb(mstb);
3961 queue_work(system_long_wq, &mgr->work);
3965 static void drm_dp_mst_up_req_work(struct work_struct *work)
3967 struct drm_dp_mst_topology_mgr *mgr =
3968 container_of(work, struct drm_dp_mst_topology_mgr,
3970 struct drm_dp_pending_up_req *up_req;
3971 bool send_hotplug = false;
3973 mutex_lock(&mgr->probe_lock);
3975 mutex_lock(&mgr->up_req_lock);
3976 up_req = list_first_entry_or_null(&mgr->up_req_list,
3977 struct drm_dp_pending_up_req,
3980 list_del(&up_req->next);
3981 mutex_unlock(&mgr->up_req_lock);
3986 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
3989 mutex_unlock(&mgr->probe_lock);
3992 drm_kms_helper_hotplug_event(mgr->dev);
3995 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
3997 struct drm_dp_pending_up_req *up_req;
3999 if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4002 if (!mgr->up_req_recv.have_eomt)
4005 up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4009 INIT_LIST_HEAD(&up_req->next);
4011 drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4013 if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4014 up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4015 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4016 up_req->msg.req_type);
4021 drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4024 if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4025 const struct drm_dp_connection_status_notify *conn_stat =
4026 &up_req->msg.u.conn_stat;
4028 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4029 conn_stat->port_number,
4030 conn_stat->legacy_device_plug_status,
4031 conn_stat->displayport_device_plug_status,
4032 conn_stat->message_capability_status,
4033 conn_stat->input_port,
4034 conn_stat->peer_device_type);
4035 } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4036 const struct drm_dp_resource_status_notify *res_stat =
4037 &up_req->msg.u.resource_stat;
4039 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4040 res_stat->port_number,
4041 res_stat->available_pbn);
4044 up_req->hdr = mgr->up_req_recv.initial_hdr;
4045 mutex_lock(&mgr->up_req_lock);
4046 list_add_tail(&up_req->next, &mgr->up_req_list);
4047 mutex_unlock(&mgr->up_req_lock);
4048 queue_work(system_long_wq, &mgr->up_req_work);
4051 memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4056 * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event
4057 * @mgr: manager to notify irq for.
4058 * @esi: 4 bytes from SINK_COUNT_ESI
4059 * @ack: 4 bytes used to ack events starting from SINK_COUNT_ESI
4060 * @handled: whether the hpd interrupt was consumed or not
4062 * This should be called from the driver when it detects a HPD IRQ,
4063 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4064 * topology manager will process the sideband messages received
4065 * as indicated in the DEVICE_SERVICE_IRQ_VECTOR_ESI0 and set the
4066 * corresponding flags that Driver has to ack the DP receiver later.
4068 * Note that driver shall also call
4069 * drm_dp_mst_hpd_irq_send_new_request() if the 'handled' is set
4070 * after calling this function, to try to kick off a new request in
4071 * the queue if the previous message transaction is completed.
4074 * drm_dp_mst_hpd_irq_send_new_request()
4076 int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u8 *esi,
4077 u8 *ack, bool *handled)
4082 sc = DP_GET_SINK_COUNT(esi[0]);
4084 if (sc != mgr->sink_count) {
4085 mgr->sink_count = sc;
4089 if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4090 ret = drm_dp_mst_handle_down_rep(mgr);
4092 ack[1] |= DP_DOWN_REP_MSG_RDY;
4095 if (esi[1] & DP_UP_REQ_MSG_RDY) {
4096 ret |= drm_dp_mst_handle_up_req(mgr);
4098 ack[1] |= DP_UP_REQ_MSG_RDY;
4103 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_handle_event);
4106 * drm_dp_mst_hpd_irq_send_new_request() - MST hotplug IRQ kick off new request
4107 * @mgr: manager to notify irq for.
4109 * This should be called from the driver when mst irq event is handled
4110 * and acked. Note that new down request should only be sent when
4111 * previous message transaction is completed. Source is not supposed to generate
4112 * interleaved message transactions.
4114 void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr)
4116 struct drm_dp_sideband_msg_tx *txmsg;
4119 mutex_lock(&mgr->qlock);
4120 txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4121 struct drm_dp_sideband_msg_tx, next);
4122 /* If last transaction is not completed yet*/
4124 txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
4125 txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
4127 mutex_unlock(&mgr->qlock);
4130 drm_dp_mst_kick_tx(mgr);
4132 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_send_new_request);
4134 * drm_dp_mst_detect_port() - get connection status for an MST port
4135 * @connector: DRM connector for this port
4136 * @ctx: The acquisition context to use for grabbing locks
4137 * @mgr: manager for this port
4138 * @port: pointer to a port
4140 * This returns the current connection state for a port.
4143 drm_dp_mst_detect_port(struct drm_connector *connector,
4144 struct drm_modeset_acquire_ctx *ctx,
4145 struct drm_dp_mst_topology_mgr *mgr,
4146 struct drm_dp_mst_port *port)
4150 /* we need to search for the port in the mgr in case it's gone */
4151 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4153 return connector_status_disconnected;
4155 ret = drm_modeset_lock(&mgr->base.lock, ctx);
4159 ret = connector_status_disconnected;
4164 switch (port->pdt) {
4165 case DP_PEER_DEVICE_NONE:
4167 case DP_PEER_DEVICE_MST_BRANCHING:
4169 ret = connector_status_connected;
4172 case DP_PEER_DEVICE_SST_SINK:
4173 ret = connector_status_connected;
4174 /* for logical ports - cache the EDID */
4175 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4176 port->cached_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4178 case DP_PEER_DEVICE_DP_LEGACY_CONV:
4180 ret = connector_status_connected;
4184 drm_dp_mst_topology_put_port(port);
4187 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4190 * drm_dp_mst_edid_read() - get EDID for an MST port
4191 * @connector: toplevel connector to get EDID for
4192 * @mgr: manager for this port
4193 * @port: unverified pointer to a port.
4195 * This returns an EDID for the port connected to a connector,
4196 * It validates the pointer still exists so the caller doesn't require a
4199 const struct drm_edid *drm_dp_mst_edid_read(struct drm_connector *connector,
4200 struct drm_dp_mst_topology_mgr *mgr,
4201 struct drm_dp_mst_port *port)
4203 const struct drm_edid *drm_edid;
4205 /* we need to search for the port in the mgr in case it's gone */
4206 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4210 if (port->cached_edid)
4211 drm_edid = drm_edid_dup(port->cached_edid);
4213 drm_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4215 drm_dp_mst_topology_put_port(port);
4219 EXPORT_SYMBOL(drm_dp_mst_edid_read);
4222 * drm_dp_mst_get_edid() - get EDID for an MST port
4223 * @connector: toplevel connector to get EDID for
4224 * @mgr: manager for this port
4225 * @port: unverified pointer to a port.
4227 * This function is deprecated; please use drm_dp_mst_edid_read() instead.
4229 * This returns an EDID for the port connected to a connector,
4230 * It validates the pointer still exists so the caller doesn't require a
4233 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
4234 struct drm_dp_mst_topology_mgr *mgr,
4235 struct drm_dp_mst_port *port)
4237 const struct drm_edid *drm_edid;
4240 drm_edid = drm_dp_mst_edid_read(connector, mgr, port);
4242 edid = drm_edid_duplicate(drm_edid_raw(drm_edid));
4244 drm_edid_free(drm_edid);
4248 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4251 * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
4252 * @state: global atomic state
4253 * @mgr: MST topology manager for the port
4254 * @port: port to find time slots for
4255 * @pbn: bandwidth required for the mode in PBN
4257 * Allocates time slots to @port, replacing any previous time slot allocations it may
4258 * have had. Any atomic drivers which support MST must call this function in
4259 * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
4260 * change the current time slot allocation for the new state, and ensure the MST
4261 * atomic state is added whenever the state of payloads in the topology changes.
4263 * Allocations set by this function are not checked against the bandwidth
4264 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4266 * Additionally, it is OK to call this function multiple times on the same
4267 * @port as needed. It is not OK however, to call this function and
4268 * drm_dp_atomic_release_time_slots() in the same atomic check phase.
4271 * drm_dp_atomic_release_time_slots()
4272 * drm_dp_mst_atomic_check()
4275 * Total slots in the atomic state assigned for this port, or a negative error
4276 * code if the port no longer exists
4278 int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
4279 struct drm_dp_mst_topology_mgr *mgr,
4280 struct drm_dp_mst_port *port, int pbn)
4282 struct drm_dp_mst_topology_state *topology_state;
4283 struct drm_dp_mst_atomic_payload *payload = NULL;
4284 struct drm_connector_state *conn_state;
4285 int prev_slots = 0, prev_bw = 0, req_slots;
4287 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4288 if (IS_ERR(topology_state))
4289 return PTR_ERR(topology_state);
4291 conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4292 topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
4294 /* Find the current allocation for this port, if any */
4295 payload = drm_atomic_get_mst_payload_state(topology_state, port);
4297 prev_slots = payload->time_slots;
4298 prev_bw = payload->pbn;
4301 * This should never happen, unless the driver tries
4302 * releasing and allocating the same timeslot allocation,
4305 if (drm_WARN_ON(mgr->dev, payload->delete)) {
4307 "cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
4313 req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
4315 drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
4316 port->connector->base.id, port->connector->name,
4317 port, prev_slots, req_slots);
4318 drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4319 port->connector->base.id, port->connector->name,
4320 port, prev_bw, pbn);
4322 /* Add the new allocation to the state, note the VCPI isn't assigned until the end */
4324 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
4328 drm_dp_mst_get_port_malloc(port);
4329 payload->port = port;
4330 payload->vc_start_slot = -1;
4331 list_add(&payload->next, &topology_state->payloads);
4333 payload->time_slots = req_slots;
4338 EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
4341 * drm_dp_atomic_release_time_slots() - Release allocated time slots
4342 * @state: global atomic state
4343 * @mgr: MST topology manager for the port
4344 * @port: The port to release the time slots from
4346 * Releases any time slots that have been allocated to a port in the atomic
4347 * state. Any atomic drivers which support MST must call this function
4348 * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
4349 * This helper will check whether time slots would be released by the new state and
4350 * respond accordingly, along with ensuring the MST state is always added to the
4351 * atomic state whenever a new state would modify the state of payloads on the
4354 * It is OK to call this even if @port has been removed from the system.
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_find_time_slots() on the same @port in a single atomic check
4361 * drm_dp_atomic_find_time_slots()
4362 * drm_dp_mst_atomic_check()
4365 * 0 on success, negative error code otherwise
4367 int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
4368 struct drm_dp_mst_topology_mgr *mgr,
4369 struct drm_dp_mst_port *port)
4371 struct drm_dp_mst_topology_state *topology_state;
4372 struct drm_dp_mst_atomic_payload *payload;
4373 struct drm_connector_state *old_conn_state, *new_conn_state;
4374 bool update_payload = true;
4376 old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
4377 if (!old_conn_state->crtc)
4380 /* If the CRTC isn't disabled by this state, don't release it's payload */
4381 new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4382 if (new_conn_state->crtc) {
4383 struct drm_crtc_state *crtc_state =
4384 drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4386 /* No modeset means no payload changes, so it's safe to not pull in the MST state */
4387 if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
4390 if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
4391 update_payload = false;
4394 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4395 if (IS_ERR(topology_state))
4396 return PTR_ERR(topology_state);
4398 topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4399 if (!update_payload)
4402 payload = drm_atomic_get_mst_payload_state(topology_state, port);
4403 if (WARN_ON(!payload)) {
4404 drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
4405 port, &topology_state->base);
4409 if (new_conn_state->crtc)
4412 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots);
4413 if (!payload->delete) {
4415 payload->delete = true;
4416 topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
4421 EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
4424 * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
4425 * @state: global atomic state
4427 * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
4428 * currently assigned to an MST topology. Drivers must call this hook from their
4429 * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
4432 * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
4434 int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
4436 struct drm_dp_mst_topology_mgr *mgr;
4437 struct drm_dp_mst_topology_state *mst_state;
4438 struct drm_crtc *crtc;
4439 struct drm_crtc_state *crtc_state;
4440 int i, j, commit_idx, num_commit_deps;
4442 for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
4443 if (!mst_state->pending_crtc_mask)
4446 num_commit_deps = hweight32(mst_state->pending_crtc_mask);
4447 mst_state->commit_deps = kmalloc_array(num_commit_deps,
4448 sizeof(*mst_state->commit_deps), GFP_KERNEL);
4449 if (!mst_state->commit_deps)
4451 mst_state->num_commit_deps = num_commit_deps;
4454 for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
4455 if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
4456 mst_state->commit_deps[commit_idx++] =
4457 drm_crtc_commit_get(crtc_state->commit);
4464 EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
4467 * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
4468 * prepare new MST state for commit
4469 * @state: global atomic state
4471 * Goes through any MST topologies in this atomic state, and waits for any pending commits which
4472 * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
4473 * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
4474 * with eachother by forcing them to be executed sequentially in situations where the only resources
4475 * the modeset objects in these commits share are an MST topology.
4477 * This function also prepares the new MST state for commit by performing some state preparation
4478 * which can't be done until this point, such as reading back the final VC start slots (which are
4479 * determined at commit-time) from the previous state.
4481 * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
4482 * or whatever their equivalent of that is.
4484 void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
4486 struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
4487 struct drm_dp_mst_topology_mgr *mgr;
4488 struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
4491 for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
4492 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
4493 ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
4495 drm_err(state->dev, "Failed to wait for %s: %d\n",
4496 old_mst_state->commit_deps[j]->crtc->name, ret);
4499 /* Now that previous state is committed, it's safe to copy over the start slot
4502 list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
4503 if (old_payload->delete)
4506 new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
4508 new_payload->vc_start_slot = old_payload->vc_start_slot;
4512 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
4515 * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
4517 * @new_conn_state: The new connector state of the &drm_connector
4518 * @mgr: The MST topology manager for the &drm_connector
4520 * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
4521 * serialize non-blocking commits happening on the real DP connector of an MST topology switching
4522 * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
4523 * MST topology will never share the same &drm_encoder.
4525 * This function takes care of this serialization issue, by checking a root MST connector's atomic
4526 * state to determine if it is about to have a modeset - and then pulling in the MST topology state
4527 * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
4529 * Drivers implementing MST must call this function from the
4530 * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
4531 * driving MST sinks.
4534 * 0 on success, negative error code otherwise
4536 int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
4537 struct drm_dp_mst_topology_mgr *mgr)
4539 struct drm_atomic_state *state = new_conn_state->state;
4540 struct drm_connector_state *old_conn_state =
4541 drm_atomic_get_old_connector_state(state, new_conn_state->connector);
4542 struct drm_crtc_state *crtc_state;
4543 struct drm_dp_mst_topology_state *mst_state = NULL;
4545 if (new_conn_state->crtc) {
4546 crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4547 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4548 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4549 if (IS_ERR(mst_state))
4550 return PTR_ERR(mst_state);
4552 mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
4556 if (old_conn_state->crtc) {
4557 crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
4558 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4560 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4561 if (IS_ERR(mst_state))
4562 return PTR_ERR(mst_state);
4565 mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4571 EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
4574 * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4575 * @mst_state: mst_state to update
4576 * @link_encoding_cap: the ecoding format on the link
4578 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4580 if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4581 mst_state->total_avail_slots = 64;
4582 mst_state->start_slot = 0;
4584 mst_state->total_avail_slots = 63;
4585 mst_state->start_slot = 1;
4588 DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4589 (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4592 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4594 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4595 int id, u8 start_slot, u8 num_slots)
4597 u8 payload_alloc[3], status;
4601 drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4602 DP_PAYLOAD_TABLE_UPDATED);
4604 payload_alloc[0] = id;
4605 payload_alloc[1] = start_slot;
4606 payload_alloc[2] = num_slots;
4608 ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4610 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4615 ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4617 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4621 if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4624 usleep_range(10000, 20000);
4627 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4637 static int do_get_act_status(struct drm_dp_aux *aux)
4642 ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4650 * drm_dp_check_act_status() - Polls for ACT handled status.
4651 * @mgr: manager to use
4653 * Tries waiting for the MST hub to finish updating it's payload table by
4654 * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4658 * 0 if the ACT was handled in time, negative error code on failure.
4660 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4663 * There doesn't seem to be any recommended retry count or timeout in
4664 * the MST specification. Since some hubs have been observed to take
4665 * over 1 second to update their payload allocations under certain
4666 * conditions, we use a rather large timeout value.
4668 const int timeout_ms = 3000;
4671 ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4672 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4673 200, timeout_ms * USEC_PER_MSEC);
4674 if (ret < 0 && status >= 0) {
4675 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4676 timeout_ms, status);
4678 } else if (status < 0) {
4680 * Failure here isn't unexpected - the hub may have
4681 * just been unplugged
4683 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4689 EXPORT_SYMBOL(drm_dp_check_act_status);
4692 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4693 * @clock: dot clock for the mode
4694 * @bpp: bpp for the mode.
4695 * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4697 * This uses the formula in the spec to calculate the PBN value for a mode.
4699 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4702 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4703 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4704 * common multiplier to render an integer PBN for all link rate/lane
4705 * counts combinations
4707 * peak_kbps *= (1006/1000)
4708 * peak_kbps *= (64/54)
4709 * peak_kbps *= 8 convert to bytes
4711 * If the bpp is in units of 1/16, further divide by 16. Put this
4712 * factor in the numerator rather than the denominator to avoid
4717 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4718 8 * 54 * 1000 * 1000);
4720 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4721 8 * 54 * 1000 * 1000);
4723 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4725 /* we want to kick the TX after we've ack the up/down IRQs. */
4726 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4728 queue_work(system_long_wq, &mgr->tx_work);
4732 * Helper function for parsing DP device types into convenient strings
4733 * for use with dp_mst_topology
4735 static const char *pdt_to_string(u8 pdt)
4738 case DP_PEER_DEVICE_NONE:
4740 case DP_PEER_DEVICE_SOURCE_OR_SST:
4741 return "SOURCE OR SST";
4742 case DP_PEER_DEVICE_MST_BRANCHING:
4743 return "MST BRANCHING";
4744 case DP_PEER_DEVICE_SST_SINK:
4746 case DP_PEER_DEVICE_DP_LEGACY_CONV:
4747 return "DP LEGACY CONV";
4753 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4754 struct drm_dp_mst_branch *mstb)
4756 struct drm_dp_mst_port *port;
4757 int tabs = mstb->lct;
4761 for (i = 0; i < tabs; i++)
4765 seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4766 list_for_each_entry(port, &mstb->ports, next) {
4767 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4771 port->input ? "input" : "output",
4772 pdt_to_string(port->pdt),
4775 port->num_sdp_streams,
4776 port->num_sdp_stream_sinks,
4777 port->fec_capable ? "true" : "false",
4780 drm_dp_mst_dump_mstb(m, port->mstb);
4784 #define DP_PAYLOAD_TABLE_SIZE 64
4786 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4791 for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4792 if (drm_dp_dpcd_read(mgr->aux,
4793 DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4800 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4801 struct drm_dp_mst_port *port, char *name,
4804 struct edid *mst_edid;
4806 mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4807 drm_edid_get_monitor_name(mst_edid, name, namelen);
4812 * drm_dp_mst_dump_topology(): dump topology to seq file.
4813 * @m: seq_file to dump output to
4814 * @mgr: manager to dump current topology for.
4816 * helper to dump MST topology to a seq file for debugfs.
4818 void drm_dp_mst_dump_topology(struct seq_file *m,
4819 struct drm_dp_mst_topology_mgr *mgr)
4821 struct drm_dp_mst_topology_state *state;
4822 struct drm_dp_mst_atomic_payload *payload;
4825 mutex_lock(&mgr->lock);
4826 if (mgr->mst_primary)
4827 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4830 mutex_unlock(&mgr->lock);
4832 ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
4836 state = to_drm_dp_mst_topology_state(mgr->base.state);
4837 seq_printf(m, "\n*** Atomic state info ***\n");
4838 seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
4839 state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div);
4841 seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | sink name |\n");
4842 for (i = 0; i < mgr->max_payloads; i++) {
4843 list_for_each_entry(payload, &state->payloads, next) {
4846 if (payload->vcpi != i || payload->delete)
4849 fetch_monitor_name(mgr, payload->port, name, sizeof(name));
4850 seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %19s\n",
4852 payload->port->port_num,
4854 payload->vc_start_slot,
4855 payload->vc_start_slot + payload->time_slots - 1,
4857 payload->dsc_enabled ? "Y" : "N",
4858 (*name != 0) ? name : "Unknown");
4862 seq_printf(m, "\n*** DPCD Info ***\n");
4863 mutex_lock(&mgr->lock);
4864 if (mgr->mst_primary) {
4865 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4868 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4869 seq_printf(m, "dpcd read failed\n");
4872 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4874 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4876 seq_printf(m, "faux/mst read failed\n");
4879 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4881 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4883 seq_printf(m, "mst ctrl read failed\n");
4886 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4888 /* dump the standard OUI branch header */
4889 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4890 if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
4891 seq_printf(m, "branch oui read failed\n");
4894 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4896 for (i = 0x3; i < 0x8 && buf[i]; i++)
4897 seq_printf(m, "%c", buf[i]);
4898 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4899 buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4900 if (dump_dp_payload_table(mgr, buf))
4901 seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4905 mutex_unlock(&mgr->lock);
4906 drm_modeset_unlock(&mgr->base.lock);
4908 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4910 static void drm_dp_tx_work(struct work_struct *work)
4912 struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4914 mutex_lock(&mgr->qlock);
4915 if (!list_empty(&mgr->tx_msg_downq))
4916 process_single_down_tx_qlock(mgr);
4917 mutex_unlock(&mgr->qlock);
4921 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4923 drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4925 if (port->connector) {
4926 drm_connector_unregister(port->connector);
4927 drm_connector_put(port->connector);
4930 drm_dp_mst_put_port_malloc(port);
4934 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4936 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4937 struct drm_dp_mst_port *port, *port_tmp;
4938 struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4939 bool wake_tx = false;
4941 mutex_lock(&mgr->lock);
4942 list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4943 list_del(&port->next);
4944 drm_dp_mst_topology_put_port(port);
4946 mutex_unlock(&mgr->lock);
4948 /* drop any tx slot msg */
4949 mutex_lock(&mstb->mgr->qlock);
4950 list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4951 if (txmsg->dst != mstb)
4954 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4955 list_del(&txmsg->next);
4958 mutex_unlock(&mstb->mgr->qlock);
4961 wake_up_all(&mstb->mgr->tx_waitq);
4963 drm_dp_mst_put_mstb_malloc(mstb);
4966 static void drm_dp_delayed_destroy_work(struct work_struct *work)
4968 struct drm_dp_mst_topology_mgr *mgr =
4969 container_of(work, struct drm_dp_mst_topology_mgr,
4970 delayed_destroy_work);
4971 bool send_hotplug = false, go_again;
4974 * Not a regular list traverse as we have to drop the destroy
4975 * connector lock before destroying the mstb/port, to avoid AB->BA
4976 * ordering between this lock and the config mutex.
4982 struct drm_dp_mst_branch *mstb;
4984 mutex_lock(&mgr->delayed_destroy_lock);
4985 mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
4986 struct drm_dp_mst_branch,
4989 list_del(&mstb->destroy_next);
4990 mutex_unlock(&mgr->delayed_destroy_lock);
4995 drm_dp_delayed_destroy_mstb(mstb);
5000 struct drm_dp_mst_port *port;
5002 mutex_lock(&mgr->delayed_destroy_lock);
5003 port = list_first_entry_or_null(&mgr->destroy_port_list,
5004 struct drm_dp_mst_port,
5007 list_del(&port->next);
5008 mutex_unlock(&mgr->delayed_destroy_lock);
5013 drm_dp_delayed_destroy_port(port);
5014 send_hotplug = true;
5020 drm_kms_helper_hotplug_event(mgr->dev);
5023 static struct drm_private_state *
5024 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5026 struct drm_dp_mst_topology_state *state, *old_state =
5027 to_dp_mst_topology_state(obj->state);
5028 struct drm_dp_mst_atomic_payload *pos, *payload;
5030 state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5034 __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5036 INIT_LIST_HEAD(&state->payloads);
5037 state->commit_deps = NULL;
5038 state->num_commit_deps = 0;
5039 state->pending_crtc_mask = 0;
5041 list_for_each_entry(pos, &old_state->payloads, next) {
5042 /* Prune leftover freed timeslot allocations */
5046 payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
5050 drm_dp_mst_get_port_malloc(payload->port);
5051 list_add(&payload->next, &state->payloads);
5054 return &state->base;
5057 list_for_each_entry_safe(pos, payload, &state->payloads, next) {
5058 drm_dp_mst_put_port_malloc(pos->port);
5066 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5067 struct drm_private_state *state)
5069 struct drm_dp_mst_topology_state *mst_state =
5070 to_dp_mst_topology_state(state);
5071 struct drm_dp_mst_atomic_payload *pos, *tmp;
5074 list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
5075 /* We only keep references to ports with active payloads */
5077 drm_dp_mst_put_port_malloc(pos->port);
5081 for (i = 0; i < mst_state->num_commit_deps; i++)
5082 drm_crtc_commit_put(mst_state->commit_deps[i]);
5084 kfree(mst_state->commit_deps);
5088 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5089 struct drm_dp_mst_branch *branch)
5091 while (port->parent) {
5092 if (port->parent == branch)
5095 if (port->parent->port_parent)
5096 port = port->parent->port_parent;
5104 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5105 struct drm_dp_mst_topology_state *state);
5108 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5109 struct drm_dp_mst_topology_state *state)
5111 struct drm_dp_mst_atomic_payload *payload;
5112 struct drm_dp_mst_port *port;
5113 int pbn_used = 0, ret;
5116 /* Check that we have at least one port in our state that's downstream
5117 * of this branch, otherwise we can skip this branch
5119 list_for_each_entry(payload, &state->payloads, next) {
5120 if (!payload->pbn ||
5121 !drm_dp_mst_port_downstream_of_branch(payload->port, mstb))
5130 if (mstb->port_parent)
5131 drm_dbg_atomic(mstb->mgr->dev,
5132 "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5133 mstb->port_parent->parent, mstb->port_parent, mstb);
5135 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5137 list_for_each_entry(port, &mstb->ports, next) {
5138 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5149 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5150 struct drm_dp_mst_topology_state *state)
5152 struct drm_dp_mst_atomic_payload *payload;
5155 if (port->pdt == DP_PEER_DEVICE_NONE)
5158 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5159 payload = drm_atomic_get_mst_payload_state(state, port);
5164 * This could happen if the sink deasserted its HPD line, but
5165 * the branch device still reports it as attached (PDT != NONE).
5167 if (!port->full_pbn) {
5168 drm_dbg_atomic(port->mgr->dev,
5169 "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5170 port->parent, port);
5174 pbn_used = payload->pbn;
5176 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5182 if (pbn_used > port->full_pbn) {
5183 drm_dbg_atomic(port->mgr->dev,
5184 "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5185 port->parent, port, pbn_used, port->full_pbn);
5189 drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5190 port->parent, port, pbn_used, port->full_pbn);
5196 drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
5197 struct drm_dp_mst_topology_state *mst_state)
5199 struct drm_dp_mst_atomic_payload *payload;
5200 int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5202 list_for_each_entry(payload, &mst_state->payloads, next) {
5203 /* Releasing payloads is always OK-even if the port is gone */
5204 if (payload->delete) {
5205 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
5210 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
5211 payload->port, payload->time_slots);
5213 avail_slots -= payload->time_slots;
5214 if (avail_slots < 0) {
5215 drm_dbg_atomic(mgr->dev,
5216 "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
5217 payload->port, mst_state, avail_slots + payload->time_slots);
5221 if (++payload_count > mgr->max_payloads) {
5222 drm_dbg_atomic(mgr->dev,
5223 "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5224 mgr, mst_state, mgr->max_payloads);
5229 if (!payload->vcpi) {
5230 payload->vcpi = ffz(mst_state->payload_mask) + 1;
5231 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
5232 payload->port, payload->vcpi);
5233 mst_state->payload_mask |= BIT(payload->vcpi - 1);
5238 mst_state->pbn_div = 0;
5240 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
5241 mgr, mst_state, mst_state->pbn_div, avail_slots,
5242 mst_state->total_avail_slots - avail_slots);
5248 * drm_dp_mst_add_affected_dsc_crtcs
5249 * @state: Pointer to the new struct drm_dp_mst_topology_state
5250 * @mgr: MST topology manager
5252 * Whenever there is a change in mst topology
5253 * DSC configuration would have to be recalculated
5254 * therefore we need to trigger modeset on all affected
5255 * CRTCs in that topology
5258 * drm_dp_mst_atomic_enable_dsc()
5260 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5262 struct drm_dp_mst_topology_state *mst_state;
5263 struct drm_dp_mst_atomic_payload *pos;
5264 struct drm_connector *connector;
5265 struct drm_connector_state *conn_state;
5266 struct drm_crtc *crtc;
5267 struct drm_crtc_state *crtc_state;
5269 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5271 if (IS_ERR(mst_state))
5272 return PTR_ERR(mst_state);
5274 list_for_each_entry(pos, &mst_state->payloads, next) {
5276 connector = pos->port->connector;
5281 conn_state = drm_atomic_get_connector_state(state, connector);
5283 if (IS_ERR(conn_state))
5284 return PTR_ERR(conn_state);
5286 crtc = conn_state->crtc;
5291 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5294 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5296 if (IS_ERR(crtc_state))
5297 return PTR_ERR(crtc_state);
5299 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5302 crtc_state->mode_changed = true;
5306 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5309 * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5310 * @state: Pointer to the new drm_atomic_state
5311 * @port: Pointer to the affected MST Port
5312 * @pbn: Newly recalculated bw required for link with DSC enabled
5313 * @enable: Boolean flag to enable or disable DSC on the port
5315 * This function enables DSC on the given Port
5316 * by recalculating its vcpi from pbn provided
5317 * and sets dsc_enable flag to keep track of which
5318 * ports have DSC enabled
5321 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5322 struct drm_dp_mst_port *port,
5323 int pbn, bool enable)
5325 struct drm_dp_mst_topology_state *mst_state;
5326 struct drm_dp_mst_atomic_payload *payload;
5329 mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5330 if (IS_ERR(mst_state))
5331 return PTR_ERR(mst_state);
5333 payload = drm_atomic_get_mst_payload_state(mst_state, port);
5335 drm_dbg_atomic(state->dev,
5336 "[MST PORT:%p] Couldn't find payload in mst state %p\n",
5341 if (payload->dsc_enabled == enable) {
5342 drm_dbg_atomic(state->dev,
5343 "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
5344 port, enable, payload->time_slots);
5345 time_slots = payload->time_slots;
5349 time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
5350 drm_dbg_atomic(state->dev,
5351 "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
5357 payload->dsc_enabled = enable;
5361 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5364 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5365 * atomic update is valid
5366 * @state: Pointer to the new &struct drm_dp_mst_topology_state
5368 * Checks the given topology state for an atomic update to ensure that it's
5369 * valid. This includes checking whether there's enough bandwidth to support
5370 * the new timeslot allocations in the atomic update.
5372 * Any atomic drivers supporting DP MST must make sure to call this after
5373 * checking the rest of their state in their
5374 * &drm_mode_config_funcs.atomic_check() callback.
5377 * drm_dp_atomic_find_time_slots()
5378 * drm_dp_atomic_release_time_slots()
5382 * 0 if the new state is valid, negative error code otherwise.
5384 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5386 struct drm_dp_mst_topology_mgr *mgr;
5387 struct drm_dp_mst_topology_state *mst_state;
5390 for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5391 if (!mgr->mst_state)
5394 ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
5398 mutex_lock(&mgr->lock);
5399 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5401 mutex_unlock(&mgr->lock);
5410 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5412 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5413 .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5414 .atomic_destroy_state = drm_dp_mst_destroy_state,
5416 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5419 * drm_atomic_get_mst_topology_state: get MST topology state
5420 * @state: global atomic state
5421 * @mgr: MST topology manager, also the private object in this case
5423 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5424 * state vtable so that the private object state returned is that of a MST
5429 * The MST topology state or error pointer.
5431 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5432 struct drm_dp_mst_topology_mgr *mgr)
5434 return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5436 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5439 * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any
5440 * @state: global atomic state
5441 * @mgr: MST topology manager, also the private object in this case
5443 * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic
5444 * state vtable so that the private object state returned is that of a MST
5449 * The old MST topology state, or NULL if there's no topology state for this MST mgr
5450 * in the global atomic state
5452 struct drm_dp_mst_topology_state *
5453 drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
5454 struct drm_dp_mst_topology_mgr *mgr)
5456 struct drm_private_state *old_priv_state =
5457 drm_atomic_get_old_private_obj_state(state, &mgr->base);
5459 return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL;
5461 EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state);
5464 * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
5465 * @state: global atomic state
5466 * @mgr: MST topology manager, also the private object in this case
5468 * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic
5469 * state vtable so that the private object state returned is that of a MST
5474 * The new MST topology state, or NULL if there's no topology state for this MST mgr
5475 * in the global atomic state
5477 struct drm_dp_mst_topology_state *
5478 drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
5479 struct drm_dp_mst_topology_mgr *mgr)
5481 struct drm_private_state *new_priv_state =
5482 drm_atomic_get_new_private_obj_state(state, &mgr->base);
5484 return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL;
5486 EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
5489 * drm_dp_mst_topology_mgr_init - initialise a topology manager
5490 * @mgr: manager struct to initialise
5491 * @dev: device providing this structure - for i2c addition.
5492 * @aux: DP helper aux channel to talk to this device
5493 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5494 * @max_payloads: maximum number of payloads this GPU can source
5495 * @conn_base_id: the connector object ID the MST device is connected to.
5497 * Return 0 for success, or negative error code on failure
5499 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5500 struct drm_device *dev, struct drm_dp_aux *aux,
5501 int max_dpcd_transaction_bytes, int max_payloads,
5504 struct drm_dp_mst_topology_state *mst_state;
5506 mutex_init(&mgr->lock);
5507 mutex_init(&mgr->qlock);
5508 mutex_init(&mgr->delayed_destroy_lock);
5509 mutex_init(&mgr->up_req_lock);
5510 mutex_init(&mgr->probe_lock);
5511 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5512 mutex_init(&mgr->topology_ref_history_lock);
5515 INIT_LIST_HEAD(&mgr->tx_msg_downq);
5516 INIT_LIST_HEAD(&mgr->destroy_port_list);
5517 INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5518 INIT_LIST_HEAD(&mgr->up_req_list);
5521 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5522 * requeuing will be also flushed when deiniting the topology manager.
5524 mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5525 if (mgr->delayed_destroy_wq == NULL)
5528 INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5529 INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5530 INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5531 INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5532 init_waitqueue_head(&mgr->tx_waitq);
5535 mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5536 mgr->max_payloads = max_payloads;
5537 mgr->conn_base_id = conn_base_id;
5539 mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5540 if (mst_state == NULL)
5543 mst_state->total_avail_slots = 63;
5544 mst_state->start_slot = 1;
5546 mst_state->mgr = mgr;
5547 INIT_LIST_HEAD(&mst_state->payloads);
5549 drm_atomic_private_obj_init(dev, &mgr->base,
5551 &drm_dp_mst_topology_state_funcs);
5555 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5558 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5559 * @mgr: manager to destroy
5561 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
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;
5572 drm_atomic_private_obj_fini(&mgr->base);
5575 mutex_destroy(&mgr->delayed_destroy_lock);
5576 mutex_destroy(&mgr->qlock);
5577 mutex_destroy(&mgr->lock);
5578 mutex_destroy(&mgr->up_req_lock);
5579 mutex_destroy(&mgr->probe_lock);
5580 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5581 mutex_destroy(&mgr->topology_ref_history_lock);
5584 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5586 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5590 if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5593 for (i = 0; i < num - 1; i++) {
5594 if (msgs[i].flags & I2C_M_RD ||
5599 return msgs[num - 1].flags & I2C_M_RD &&
5600 msgs[num - 1].len <= 0xff;
5603 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5607 for (i = 0; i < num - 1; i++) {
5608 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5613 return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5616 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5617 struct drm_dp_mst_port *port,
5618 struct i2c_msg *msgs, int num)
5620 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5622 struct drm_dp_sideband_msg_req_body msg;
5623 struct drm_dp_sideband_msg_tx *txmsg = NULL;
5626 memset(&msg, 0, sizeof(msg));
5627 msg.req_type = DP_REMOTE_I2C_READ;
5628 msg.u.i2c_read.num_transactions = num - 1;
5629 msg.u.i2c_read.port_number = port->port_num;
5630 for (i = 0; i < num - 1; i++) {
5631 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5632 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5633 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5634 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5636 msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5637 msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5639 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5646 drm_dp_encode_sideband_req(&msg, txmsg);
5648 drm_dp_queue_down_tx(mgr, txmsg);
5650 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5653 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5657 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5661 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5669 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5670 struct drm_dp_mst_port *port,
5671 struct i2c_msg *msgs, int num)
5673 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5675 struct drm_dp_sideband_msg_req_body msg;
5676 struct drm_dp_sideband_msg_tx *txmsg = NULL;
5679 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5684 for (i = 0; i < num; i++) {
5685 memset(&msg, 0, sizeof(msg));
5686 msg.req_type = DP_REMOTE_I2C_WRITE;
5687 msg.u.i2c_write.port_number = port->port_num;
5688 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5689 msg.u.i2c_write.num_bytes = msgs[i].len;
5690 msg.u.i2c_write.bytes = msgs[i].buf;
5692 memset(txmsg, 0, sizeof(*txmsg));
5695 drm_dp_encode_sideband_req(&msg, txmsg);
5696 drm_dp_queue_down_tx(mgr, txmsg);
5698 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5700 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5715 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5716 struct i2c_msg *msgs, int num)
5718 struct drm_dp_aux *aux = adapter->algo_data;
5719 struct drm_dp_mst_port *port =
5720 container_of(aux, struct drm_dp_mst_port, aux);
5721 struct drm_dp_mst_branch *mstb;
5722 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5725 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5729 if (remote_i2c_read_ok(msgs, num)) {
5730 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5731 } else if (remote_i2c_write_ok(msgs, num)) {
5732 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5734 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5738 drm_dp_mst_topology_put_mstb(mstb);
5742 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5744 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5745 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5746 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5747 I2C_FUNC_10BIT_ADDR;
5750 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5751 .functionality = drm_dp_mst_i2c_functionality,
5752 .master_xfer = drm_dp_mst_i2c_xfer,
5756 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5757 * @port: The port to add the I2C bus on
5759 * Returns 0 on success or a negative error code on failure.
5761 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5763 struct drm_dp_aux *aux = &port->aux;
5764 struct device *parent_dev = port->mgr->dev->dev;
5766 aux->ddc.algo = &drm_dp_mst_i2c_algo;
5767 aux->ddc.algo_data = aux;
5768 aux->ddc.retries = 3;
5770 aux->ddc.class = I2C_CLASS_DDC;
5771 aux->ddc.owner = THIS_MODULE;
5772 /* FIXME: set the kdev of the port's connector as parent */
5773 aux->ddc.dev.parent = parent_dev;
5774 aux->ddc.dev.of_node = parent_dev->of_node;
5776 strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5777 sizeof(aux->ddc.name));
5779 return i2c_add_adapter(&aux->ddc);
5783 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5784 * @port: The port to remove the I2C bus from
5786 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5788 i2c_del_adapter(&port->aux.ddc);
5792 * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5793 * @port: The port to check
5795 * A single physical MST hub object can be represented in the topology
5796 * by multiple branches, with virtual ports between those branches.
5798 * As of DP1.4, An MST hub with internal (virtual) ports must expose
5799 * certain DPCD registers over those ports. See sections 2.6.1.1.1
5800 * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5802 * May acquire mgr->lock
5805 * true if the port is a virtual DP peer device, false otherwise
5807 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5809 struct drm_dp_mst_port *downstream_port;
5811 if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5814 /* Virtual DP Sink (Internal Display Panel) */
5815 if (port->port_num >= 8)
5818 /* DP-to-HDMI Protocol Converter */
5819 if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5825 mutex_lock(&port->mgr->lock);
5826 if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5828 port->mstb->num_ports == 2) {
5829 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5830 if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5831 !downstream_port->input) {
5832 mutex_unlock(&port->mgr->lock);
5837 mutex_unlock(&port->mgr->lock);
5843 * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5844 * @port: The port to check. A leaf of the MST tree with an attached display.
5846 * Depending on the situation, DSC may be enabled via the endpoint aux,
5847 * the immediately upstream aux, or the connector's physical aux.
5849 * This is both the correct aux to read DSC_CAPABILITY and the
5850 * correct aux to write DSC_ENABLED.
5852 * This operation can be expensive (up to four aux reads), so
5853 * the caller should cache the return.
5856 * NULL if DSC cannot be enabled on this port, otherwise the aux device
5858 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5860 struct drm_dp_mst_port *immediate_upstream_port;
5861 struct drm_dp_mst_port *fec_port;
5862 struct drm_dp_desc desc = {};
5869 if (port->parent->port_parent)
5870 immediate_upstream_port = port->parent->port_parent;
5872 immediate_upstream_port = NULL;
5874 fec_port = immediate_upstream_port;
5877 * Each physical link (i.e. not a virtual port) between the
5878 * output and the primary device must support FEC
5880 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5881 !fec_port->fec_capable)
5884 fec_port = fec_port->parent->port_parent;
5887 /* DP-to-DP peer device */
5888 if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5891 if (drm_dp_dpcd_read(&port->aux,
5892 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5894 if (drm_dp_dpcd_read(&port->aux,
5895 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5897 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5898 DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5901 /* Enpoint decompression with DP-to-DP peer device */
5902 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5903 (endpoint_fec & DP_FEC_CAPABLE) &&
5904 (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
5905 port->passthrough_aux = &immediate_upstream_port->aux;
5909 /* Virtual DPCD decompression with DP-to-DP peer device */
5910 return &immediate_upstream_port->aux;
5913 /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5914 if (drm_dp_mst_is_virtual_dpcd(port))
5919 * Applies to ports for which:
5920 * - Physical aux has Synaptics OUI
5921 * - DPv1.4 or higher
5922 * - Port is on primary branch device
5923 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5925 if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5928 if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5929 port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5930 port->parent == port->mgr->mst_primary) {
5931 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5933 if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5936 if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5937 ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5938 != DP_DWN_STRM_PORT_TYPE_ANALOG))
5939 return port->mgr->aux;
5943 * The check below verifies if the MST sink
5944 * connected to the GPU is capable of DSC -
5945 * therefore the endpoint needs to be
5946 * both DSC and FEC capable.
5948 if (drm_dp_dpcd_read(&port->aux,
5949 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5951 if (drm_dp_dpcd_read(&port->aux,
5952 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5954 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5955 (endpoint_fec & DP_FEC_CAPABLE))
5960 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);