drivers/thunderbolt/path.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt driver - path/tunnel functionality
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  * Copyright (C) 2019, Intel Corporation
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/errno.h>
  11 #include <linux/delay.h>
  12 #include <linux/ktime.h>
  13
  14 #include "tb.h"
  15
  16 static void tb_dump_hop(const struct tb_path_hop *hop, const struct tb_regs_hop *regs)
  17 {
  18         const struct tb_port *port = hop->in_port;
  19
  20         tb_port_dbg(port, " In HopID: %d => Out port: %d Out HopID: %d\n",
  21                     hop->in_hop_index, regs->out_port, regs->next_hop);
  22         tb_port_dbg(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
  23                     regs->weight, regs->priority,
  24                     regs->initial_credits, regs->drop_packages);
  25         tb_port_dbg(port, "   Counter enabled: %d Counter index: %d\n",
  26                     regs->counter_enable, regs->counter);
  27         tb_port_dbg(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
  28                     regs->ingress_fc, regs->egress_fc,
  29                     regs->ingress_shared_buffer, regs->egress_shared_buffer);
  30         tb_port_dbg(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
  31                     regs->unknown1, regs->unknown2, regs->unknown3);
  32 }
  33
  34 static struct tb_port *tb_path_find_dst_port(struct tb_port *src, int src_hopid,
  35                                              int dst_hopid)
  36 {
  37         struct tb_port *port, *out_port = NULL;
  38         struct tb_regs_hop hop;
  39         struct tb_switch *sw;
  40         int i, ret, hopid;
  41
  42         hopid = src_hopid;
  43         port = src;
  44
  45         for (i = 0; port && i < TB_PATH_MAX_HOPS; i++) {
  46                 sw = port->sw;
  47
  48                 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hopid, 2);
  49                 if (ret) {
  50                         tb_port_warn(port, "failed to read path at %d\n", hopid);
  51                         return NULL;
  52                 }
  53
  54                 if (!hop.enable)
  55                         return NULL;
  56
  57                 out_port = &sw->ports[hop.out_port];
  58                 hopid = hop.next_hop;
  59                 port = out_port->remote;
  60         }
  61
  62         return out_port && hopid == dst_hopid ? out_port : NULL;
  63 }
  64
  65 static int tb_path_find_src_hopid(struct tb_port *src,
  66         const struct tb_port *dst, int dst_hopid)
  67 {
  68         struct tb_port *out;
  69         int i;
  70
  71         for (i = TB_PATH_MIN_HOPID; i <= src->config.max_in_hop_id; i++) {
  72                 out = tb_path_find_dst_port(src, i, dst_hopid);
  73                 if (out == dst)
  74                         return i;
  75         }
  76
  77         return 0;
  78 }
  79
  80 /**
  81  * tb_path_discover() - Discover a path
  82  * @src: First input port of a path
  83  * @src_hopid: Starting HopID of a path (%-1 if don't care)
  84  * @dst: Expected destination port of the path (%NULL if don't care)
  85  * @dst_hopid: HopID to the @dst (%-1 if don't care)
  86  * @last: Last port is filled here if not %NULL
  87  * @name: Name of the path
  88  * @alloc_hopid: Allocate HopIDs for the ports
  89  *
  90  * Follows a path starting from @src and @src_hopid to the last output
  91  * port of the path. Allocates HopIDs for the visited ports (if
  92  * @alloc_hopid is true). Call tb_path_free() to release the path and
  93  * allocated HopIDs when the path is not needed anymore.
  94  *
  95  * Note function discovers also incomplete paths so caller should check
  96  * that the @dst port is the expected one. If it is not, the path can be
  97  * cleaned up by calling tb_path_deactivate() before tb_path_free().
  98  *
  99  * Return: Discovered path on success, %NULL in case of failure
 100  */
 101 struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
 102                                  struct tb_port *dst, int dst_hopid,
 103                                  struct tb_port **last, const char *name,
 104                                  bool alloc_hopid)
 105 {
 106         struct tb_port *out_port;
 107         struct tb_regs_hop hop;
 108         struct tb_path *path;
 109         struct tb_switch *sw;
 110         struct tb_port *p;
 111         size_t num_hops;
 112         int ret, i, h;
 113
 114         if (src_hopid < 0 && dst) {
 115                 /*
 116                  * For incomplete paths the intermediate HopID can be
 117                  * different from the one used by the protocol adapter
 118                  * so in that case find a path that ends on @dst with
 119                  * matching @dst_hopid. That should give us the correct
 120                  * HopID for the @src.
 121                  */
 122                 src_hopid = tb_path_find_src_hopid(src, dst, dst_hopid);
 123                 if (!src_hopid)
 124                         return NULL;
 125         }
 126
 127         p = src;
 128         h = src_hopid;
 129         num_hops = 0;
 130
 131         for (i = 0; p && i < TB_PATH_MAX_HOPS; i++) {
 132                 sw = p->sw;
 133
 134                 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
 135                 if (ret) {
 136                         tb_port_warn(p, "failed to read path at %d\n", h);
 137                         return NULL;
 138                 }
 139
 140                 /* If the hop is not enabled we got an incomplete path */
 141                 if (!hop.enable)
 142                         break;
 143
 144                 out_port = &sw->ports[hop.out_port];
 145                 if (last)
 146                         *last = out_port;
 147
 148                 h = hop.next_hop;
 149                 p = out_port->remote;
 150                 num_hops++;
 151         }
 152
 153         path = kzalloc(sizeof(*path), GFP_KERNEL);
 154         if (!path)
 155                 return NULL;
 156
 157         path->name = name;
 158         path->tb = src->sw->tb;
 159         path->path_length = num_hops;
 160         path->activated = true;
 161         path->alloc_hopid = alloc_hopid;
 162
 163         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
 164         if (!path->hops) {
 165                 kfree(path);
 166                 return NULL;
 167         }
 168
 169         tb_dbg(path->tb, "discovering %s path starting from %llx:%u\n",
 170                path->name, tb_route(src->sw), src->port);
 171
 172         p = src;
 173         h = src_hopid;
 174
 175         for (i = 0; i < num_hops; i++) {
 176                 int next_hop;
 177
 178                 sw = p->sw;
 179
 180                 ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
 181                 if (ret) {
 182                         tb_port_warn(p, "failed to read path at %d\n", h);
 183                         goto err;
 184                 }
 185
 186                 if (alloc_hopid && tb_port_alloc_in_hopid(p, h, h) < 0)
 187                         goto err;
 188
 189                 out_port = &sw->ports[hop.out_port];
 190                 next_hop = hop.next_hop;
 191
 192                 if (alloc_hopid &&
 193                     tb_port_alloc_out_hopid(out_port, next_hop, next_hop) < 0) {
 194                         tb_port_release_in_hopid(p, h);
 195                         goto err;
 196                 }
 197
 198                 path->hops[i].in_port = p;
 199                 path->hops[i].in_hop_index = h;
 200                 path->hops[i].in_counter_index = -1;
 201                 path->hops[i].out_port = out_port;
 202                 path->hops[i].next_hop_index = next_hop;
 203
 204                 tb_dump_hop(&path->hops[i], &hop);
 205
 206                 h = next_hop;
 207                 p = out_port->remote;
 208         }
 209
 210         tb_dbg(path->tb, "path discovery complete\n");
 211         return path;
 212
 213 err:
 214         tb_port_warn(src, "failed to discover path starting at HopID %d\n",
 215                      src_hopid);
 216         tb_path_free(path);
 217         return NULL;
 218 }
 219
 220 /**
 221  * tb_path_alloc() - allocate a thunderbolt path between two ports
 222  * @tb: Domain pointer
 223  * @src: Source port of the path
 224  * @src_hopid: HopID used for the first ingress port in the path
 225  * @dst: Destination port of the path
 226  * @dst_hopid: HopID used for the last egress port in the path
 227  * @link_nr: Preferred link if there are dual links on the path
 228  * @name: Name of the path
 229  *
 230  * Creates path between two ports starting with given @src_hopid. Reserves
 231  * HopIDs for each port (they can be different from @src_hopid depending on
 232  * how many HopIDs each port already have reserved). If there are dual
 233  * links on the path, prioritizes using @link_nr but takes into account
 234  * that the lanes may be bonded.
 235  *
 236  * Return: Returns a tb_path on success or NULL on failure.
 237  */
 238 struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
 239                               struct tb_port *dst, int dst_hopid, int link_nr,
 240                               const char *name)
 241 {
 242         struct tb_port *in_port, *out_port, *first_port, *last_port;
 243         int in_hopid, out_hopid;
 244         struct tb_path *path;
 245         size_t num_hops;
 246         int i, ret;
 247
 248         path = kzalloc(sizeof(*path), GFP_KERNEL);
 249         if (!path)
 250                 return NULL;
 251
 252         first_port = last_port = NULL;
 253         i = 0;
 254         tb_for_each_port_on_path(src, dst, in_port) {
 255                 if (!first_port)
 256                         first_port = in_port;
 257                 last_port = in_port;
 258                 i++;
 259         }
 260
 261         /* Check that src and dst are reachable */
 262         if (first_port != src || last_port != dst) {
 263                 kfree(path);
 264                 return NULL;
 265         }
 266
 267         /* Each hop takes two ports */
 268         num_hops = i / 2;
 269
 270         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
 271         if (!path->hops) {
 272                 kfree(path);
 273                 return NULL;
 274         }
 275
 276         path->alloc_hopid = true;
 277
 278         in_hopid = src_hopid;
 279         out_port = NULL;
 280
 281         for (i = 0; i < num_hops; i++) {
 282                 in_port = tb_next_port_on_path(src, dst, out_port);
 283                 if (!in_port)
 284                         goto err;
 285
 286                 /* When lanes are bonded primary link must be used */
 287                 if (!in_port->bonded && in_port->dual_link_port &&
 288                     in_port->link_nr != link_nr)
 289                         in_port = in_port->dual_link_port;
 290
 291                 ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
 292                 if (ret < 0)
 293                         goto err;
 294                 in_hopid = ret;
 295
 296                 out_port = tb_next_port_on_path(src, dst, in_port);
 297                 if (!out_port)
 298                         goto err;
 299
 300                 /*
 301                  * Pick up right port when going from non-bonded to
 302                  * bonded or from bonded to non-bonded.
 303                  */
 304                 if (out_port->dual_link_port) {
 305                         if (!in_port->bonded && out_port->bonded &&
 306                             out_port->link_nr) {
 307                                 /*
 308                                  * Use primary link when going from
 309                                  * non-bonded to bonded.
 310                                  */
 311                                 out_port = out_port->dual_link_port;
 312                         } else if (!out_port->bonded &&
 313                                    out_port->link_nr != link_nr) {
 314                                 /*
 315                                  * If out port is not bonded follow
 316                                  * link_nr.
 317                                  */
 318                                 out_port = out_port->dual_link_port;
 319                         }
 320                 }
 321
 322                 if (i == num_hops - 1)
 323                         ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
 324                                                       dst_hopid);
 325                 else
 326                         ret = tb_port_alloc_out_hopid(out_port, -1, -1);
 327
 328                 if (ret < 0)
 329                         goto err;
 330                 out_hopid = ret;
 331
 332                 path->hops[i].in_hop_index = in_hopid;
 333                 path->hops[i].in_port = in_port;
 334                 path->hops[i].in_counter_index = -1;
 335                 path->hops[i].out_port = out_port;
 336                 path->hops[i].next_hop_index = out_hopid;
 337
 338                 in_hopid = out_hopid;
 339         }
 340
 341         path->tb = tb;
 342         path->path_length = num_hops;
 343         path->name = name;
 344
 345         return path;
 346
 347 err:
 348         tb_path_free(path);
 349         return NULL;
 350 }
 351
 352 /**
 353  * tb_path_free() - free a path
 354  * @path: Path to free
 355  *
 356  * Frees a path. The path does not need to be deactivated.
 357  */
 358 void tb_path_free(struct tb_path *path)
 359 {
 360         if (path->alloc_hopid) {
 361                 int i;
 362
 363                 for (i = 0; i < path->path_length; i++) {
 364                         const struct tb_path_hop *hop = &path->hops[i];
 365
 366                         if (hop->in_port)
 367                                 tb_port_release_in_hopid(hop->in_port,
 368                                                          hop->in_hop_index);
 369                         if (hop->out_port)
 370                                 tb_port_release_out_hopid(hop->out_port,
 371                                                           hop->next_hop_index);
 372                 }
 373         }
 374
 375         kfree(path->hops);
 376         kfree(path);
 377 }
 378
 379 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
 380 {
 381         int i, res;
 382         for (i = first_hop; i < path->path_length; i++) {
 383                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 384                                               -path->hops[i].nfc_credits);
 385                 if (res)
 386                         tb_port_warn(path->hops[i].in_port,
 387                                      "nfc credits deallocation failed for hop %d\n",
 388                                      i);
 389         }
 390 }
 391
 392 static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
 393                                     bool clear_fc)
 394 {
 395         struct tb_regs_hop hop;
 396         ktime_t timeout;
 397         int ret;
 398
 399         /* Disable the path */
 400         ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 401         if (ret)
 402                 return ret;
 403
 404         /* Already disabled */
 405         if (!hop.enable)
 406                 return 0;
 407
 408         hop.enable = 0;
 409
 410         ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 411         if (ret)
 412                 return ret;
 413
 414         /* Wait until it is drained */
 415         timeout = ktime_add_ms(ktime_get(), 500);
 416         do {
 417                 ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
 418                 if (ret)
 419                         return ret;
 420
 421                 if (!hop.pending) {
 422                         if (clear_fc) {
 423                                 /*
 424                                  * Clear flow control. Protocol adapters
 425                                  * IFC and ISE bits are vendor defined
 426                                  * in the USB4 spec so we clear them
 427                                  * only for pre-USB4 adapters.
 428                                  */
 429                                 if (!tb_switch_is_usb4(port->sw)) {
 430                                         hop.ingress_fc = 0;
 431                                         hop.ingress_shared_buffer = 0;
 432                                 }
 433                                 hop.egress_fc = 0;
 434                                 hop.egress_shared_buffer = 0;
 435
 436                                 return tb_port_write(port, &hop, TB_CFG_HOPS,
 437                                                      2 * hop_index, 2);
 438                         }
 439
 440                         return 0;
 441                 }
 442
 443                 usleep_range(10, 20);
 444         } while (ktime_before(ktime_get(), timeout));
 445
 446         return -ETIMEDOUT;
 447 }
 448
 449 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
 450 {
 451         int i, res;
 452
 453         for (i = first_hop; i < path->path_length; i++) {
 454                 res = __tb_path_deactivate_hop(path->hops[i].in_port,
 455                                                path->hops[i].in_hop_index,
 456                                                path->clear_fc);
 457                 if (res && res != -ENODEV)
 458                         tb_port_warn(path->hops[i].in_port,
 459                                      "hop deactivation failed for hop %d, index %d\n",
 460                                      i, path->hops[i].in_hop_index);
 461         }
 462 }
 463
 464 void tb_path_deactivate(struct tb_path *path)
 465 {
 466         if (!path->activated) {
 467                 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
 468                 return;
 469         }
 470         tb_dbg(path->tb,
 471                "deactivating %s path from %llx:%u to %llx:%u\n",
 472                path->name, tb_route(path->hops[0].in_port->sw),
 473                path->hops[0].in_port->port,
 474                tb_route(path->hops[path->path_length - 1].out_port->sw),
 475                path->hops[path->path_length - 1].out_port->port);
 476         __tb_path_deactivate_hops(path, 0);
 477         __tb_path_deallocate_nfc(path, 0);
 478         path->activated = false;
 479 }
 480
 481 /**
 482  * tb_path_activate() - activate a path
 483  * @path: Path to activate
 484  *
 485  * Activate a path starting with the last hop and iterating backwards. The
 486  * caller must fill path->hops before calling tb_path_activate().
 487  *
 488  * Return: Returns 0 on success or an error code on failure.
 489  */
 490 int tb_path_activate(struct tb_path *path)
 491 {
 492         int i, res;
 493         enum tb_path_port out_mask, in_mask;
 494         if (path->activated) {
 495                 tb_WARN(path->tb, "trying to activate already activated path\n");
 496                 return -EINVAL;
 497         }
 498
 499         tb_dbg(path->tb,
 500                "activating %s path from %llx:%u to %llx:%u\n",
 501                path->name, tb_route(path->hops[0].in_port->sw),
 502                path->hops[0].in_port->port,
 503                tb_route(path->hops[path->path_length - 1].out_port->sw),
 504                path->hops[path->path_length - 1].out_port->port);
 505
 506         /* Clear counters. */
 507         for (i = path->path_length - 1; i >= 0; i--) {
 508                 if (path->hops[i].in_counter_index == -1)
 509                         continue;
 510                 res = tb_port_clear_counter(path->hops[i].in_port,
 511                                             path->hops[i].in_counter_index);
 512                 if (res)
 513                         goto err;
 514         }
 515
 516         /* Add non flow controlled credits. */
 517         for (i = path->path_length - 1; i >= 0; i--) {
 518                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 519                                               path->hops[i].nfc_credits);
 520                 if (res) {
 521                         __tb_path_deallocate_nfc(path, i);
 522                         goto err;
 523                 }
 524         }
 525
 526         /* Activate hops. */
 527         for (i = path->path_length - 1; i >= 0; i--) {
 528                 struct tb_regs_hop hop = { 0 };
 529
 530                 /* If it is left active deactivate it first */
 531                 __tb_path_deactivate_hop(path->hops[i].in_port,
 532                                 path->hops[i].in_hop_index, path->clear_fc);
 533
 534                 /* dword 0 */
 535                 hop.next_hop = path->hops[i].next_hop_index;
 536                 hop.out_port = path->hops[i].out_port->port;
 537                 hop.initial_credits = path->hops[i].initial_credits;
 538                 hop.unknown1 = 0;
 539                 hop.enable = 1;
 540
 541                 /* dword 1 */
 542                 out_mask = (i == path->path_length - 1) ?
 543                                 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
 544                 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
 545                 hop.weight = path->weight;
 546                 hop.unknown2 = 0;
 547                 hop.priority = path->priority;
 548                 hop.drop_packages = path->drop_packages;
 549                 hop.counter = path->hops[i].in_counter_index;
 550                 hop.counter_enable = path->hops[i].in_counter_index != -1;
 551                 hop.ingress_fc = path->ingress_fc_enable & in_mask;
 552                 hop.egress_fc = path->egress_fc_enable & out_mask;
 553                 hop.ingress_shared_buffer = path->ingress_shared_buffer
 554                                             & in_mask;
 555                 hop.egress_shared_buffer = path->egress_shared_buffer
 556                                             & out_mask;
 557                 hop.unknown3 = 0;
 558
 559                 tb_port_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
 560                 tb_dump_hop(&path->hops[i], &hop);
 561                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 562                                     2 * path->hops[i].in_hop_index, 2);
 563                 if (res) {
 564                         __tb_path_deactivate_hops(path, i);
 565                         __tb_path_deallocate_nfc(path, 0);
 566                         goto err;
 567                 }
 568         }
 569         path->activated = true;
 570         tb_dbg(path->tb, "path activation complete\n");
 571         return 0;
 572 err:
 573         tb_WARN(path->tb, "path activation failed\n");
 574         return res;
 575 }
 576
 577 /**
 578  * tb_path_is_invalid() - check whether any ports on the path are invalid
 579  * @path: Path to check
 580  *
 581  * Return: Returns true if the path is invalid, false otherwise.
 582  */
 583 bool tb_path_is_invalid(struct tb_path *path)
 584 {
 585         int i = 0;
 586         for (i = 0; i < path->path_length; i++) {
 587                 if (path->hops[i].in_port->sw->is_unplugged)
 588                         return true;
 589                 if (path->hops[i].out_port->sw->is_unplugged)
 590                         return true;
 591         }
 592         return false;
 593 }
 594
 595 /**
 596  * tb_path_port_on_path() - Does the path go through certain port
 597  * @path: Path to check
 598  * @port: Switch to check
 599  *
 600  * Goes over all hops on path and checks if @port is any of them.
 601  * Direction does not matter.
 602  */
 603 bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
 604 {
 605         int i;
 606
 607         for (i = 0; i < path->path_length; i++) {
 608                 if (path->hops[i].in_port == port ||
 609                     path->hops[i].out_port == port)
 610                         return true;
 611         }
 612
 613         return false;
 614 }