drivers/greybus/connection.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Greybus connections
   4  *
   5  * Copyright 2014 Google Inc.
   6  * Copyright 2014 Linaro Ltd.
   7  */
   8
   9 #include <linux/workqueue.h>
  10 #include <linux/greybus.h>
  11
  12 #include "greybus_trace.h"
  13
  14 #define GB_CONNECTION_CPORT_QUIESCE_TIMEOUT     1000
  15
  16 static void gb_connection_kref_release(struct kref *kref);
  17
  18 static DEFINE_SPINLOCK(gb_connections_lock);
  19 static DEFINE_MUTEX(gb_connection_mutex);
  20
  21 /* Caller holds gb_connection_mutex. */
  22 static bool gb_connection_cport_in_use(struct gb_interface *intf, u16 cport_id)
  23 {
  24         struct gb_host_device *hd = intf->hd;
  25         struct gb_connection *connection;
  26
  27         list_for_each_entry(connection, &hd->connections, hd_links) {
  28                 if (connection->intf == intf &&
  29                     connection->intf_cport_id == cport_id)
  30                         return true;
  31         }
  32
  33         return false;
  34 }
  35
  36 static void gb_connection_get(struct gb_connection *connection)
  37 {
  38         kref_get(&connection->kref);
  39
  40         trace_gb_connection_get(connection);
  41 }
  42
  43 static void gb_connection_put(struct gb_connection *connection)
  44 {
  45         trace_gb_connection_put(connection);
  46
  47         kref_put(&connection->kref, gb_connection_kref_release);
  48 }
  49
  50 /*
  51  * Returns a reference-counted pointer to the connection if found.
  52  */
  53 static struct gb_connection *
  54 gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
  55 {
  56         struct gb_connection *connection;
  57         unsigned long flags;
  58
  59         spin_lock_irqsave(&gb_connections_lock, flags);
  60         list_for_each_entry(connection, &hd->connections, hd_links)
  61                 if (connection->hd_cport_id == cport_id) {
  62                         gb_connection_get(connection);
  63                         goto found;
  64                 }
  65         connection = NULL;
  66 found:
  67         spin_unlock_irqrestore(&gb_connections_lock, flags);
  68
  69         return connection;
  70 }
  71
  72 /*
  73  * Callback from the host driver to let us know that data has been
  74  * received on the bundle.
  75  */
  76 void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
  77                        u8 *data, size_t length)
  78 {
  79         struct gb_connection *connection;
  80
  81         trace_gb_hd_in(hd);
  82
  83         connection = gb_connection_hd_find(hd, cport_id);
  84         if (!connection) {
  85                 dev_err(&hd->dev,
  86                         "nonexistent connection (%zu bytes dropped)\n", length);
  87                 return;
  88         }
  89         gb_connection_recv(connection, data, length);
  90         gb_connection_put(connection);
  91 }
  92 EXPORT_SYMBOL_GPL(greybus_data_rcvd);
  93
  94 static void gb_connection_kref_release(struct kref *kref)
  95 {
  96         struct gb_connection *connection;
  97
  98         connection = container_of(kref, struct gb_connection, kref);
  99
 100         trace_gb_connection_release(connection);
 101
 102         kfree(connection);
 103 }
 104
 105 static void gb_connection_init_name(struct gb_connection *connection)
 106 {
 107         u16 hd_cport_id = connection->hd_cport_id;
 108         u16 cport_id = 0;
 109         u8 intf_id = 0;
 110
 111         if (connection->intf) {
 112                 intf_id = connection->intf->interface_id;
 113                 cport_id = connection->intf_cport_id;
 114         }
 115
 116         snprintf(connection->name, sizeof(connection->name),
 117                  "%u/%u:%u", hd_cport_id, intf_id, cport_id);
 118 }
 119
 120 /*
 121  * _gb_connection_create() - create a Greybus connection
 122  * @hd:                 host device of the connection
 123  * @hd_cport_id:        host-device cport id, or -1 for dynamic allocation
 124  * @intf:               remote interface, or NULL for static connections
 125  * @bundle:             remote-interface bundle (may be NULL)
 126  * @cport_id:           remote-interface cport id, or 0 for static connections
 127  * @handler:            request handler (may be NULL)
 128  * @flags:              connection flags
 129  *
 130  * Create a Greybus connection, representing the bidirectional link
 131  * between a CPort on a (local) Greybus host device and a CPort on
 132  * another Greybus interface.
 133  *
 134  * A connection also maintains the state of operations sent over the
 135  * connection.
 136  *
 137  * Serialised against concurrent create and destroy using the
 138  * gb_connection_mutex.
 139  *
 140  * Return: A pointer to the new connection if successful, or an ERR_PTR
 141  * otherwise.
 142  */
 143 static struct gb_connection *
 144 _gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 145                       struct gb_interface *intf,
 146                       struct gb_bundle *bundle, int cport_id,
 147                       gb_request_handler_t handler,
 148                       unsigned long flags)
 149 {
 150         struct gb_connection *connection;
 151         int ret;
 152
 153         mutex_lock(&gb_connection_mutex);
 154
 155         if (intf && gb_connection_cport_in_use(intf, cport_id)) {
 156                 dev_err(&intf->dev, "cport %u already in use\n", cport_id);
 157                 ret = -EBUSY;
 158                 goto err_unlock;
 159         }
 160
 161         ret = gb_hd_cport_allocate(hd, hd_cport_id, flags);
 162         if (ret < 0) {
 163                 dev_err(&hd->dev, "failed to allocate cport: %d\n", ret);
 164                 goto err_unlock;
 165         }
 166         hd_cport_id = ret;
 167
 168         connection = kzalloc(sizeof(*connection), GFP_KERNEL);
 169         if (!connection) {
 170                 ret = -ENOMEM;
 171                 goto err_hd_cport_release;
 172         }
 173
 174         connection->hd_cport_id = hd_cport_id;
 175         connection->intf_cport_id = cport_id;
 176         connection->hd = hd;
 177         connection->intf = intf;
 178         connection->bundle = bundle;
 179         connection->handler = handler;
 180         connection->flags = flags;
 181         if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
 182                 connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
 183         connection->state = GB_CONNECTION_STATE_DISABLED;
 184
 185         atomic_set(&connection->op_cycle, 0);
 186         mutex_init(&connection->mutex);
 187         spin_lock_init(&connection->lock);
 188         INIT_LIST_HEAD(&connection->operations);
 189
 190         connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
 191                                          dev_name(&hd->dev), hd_cport_id);
 192         if (!connection->wq) {
 193                 ret = -ENOMEM;
 194                 goto err_free_connection;
 195         }
 196
 197         kref_init(&connection->kref);
 198
 199         gb_connection_init_name(connection);
 200
 201         spin_lock_irq(&gb_connections_lock);
 202         list_add(&connection->hd_links, &hd->connections);
 203
 204         if (bundle)
 205                 list_add(&connection->bundle_links, &bundle->connections);
 206         else
 207                 INIT_LIST_HEAD(&connection->bundle_links);
 208
 209         spin_unlock_irq(&gb_connections_lock);
 210
 211         mutex_unlock(&gb_connection_mutex);
 212
 213         trace_gb_connection_create(connection);
 214
 215         return connection;
 216
 217 err_free_connection:
 218         kfree(connection);
 219 err_hd_cport_release:
 220         gb_hd_cport_release(hd, hd_cport_id);
 221 err_unlock:
 222         mutex_unlock(&gb_connection_mutex);
 223
 224         return ERR_PTR(ret);
 225 }
 226
 227 struct gb_connection *
 228 gb_connection_create_static(struct gb_host_device *hd, u16 hd_cport_id,
 229                             gb_request_handler_t handler)
 230 {
 231         return _gb_connection_create(hd, hd_cport_id, NULL, NULL, 0, handler,
 232                                      GB_CONNECTION_FLAG_HIGH_PRIO);
 233 }
 234
 235 struct gb_connection *
 236 gb_connection_create_control(struct gb_interface *intf)
 237 {
 238         return _gb_connection_create(intf->hd, -1, intf, NULL, 0, NULL,
 239                                      GB_CONNECTION_FLAG_CONTROL |
 240                                      GB_CONNECTION_FLAG_HIGH_PRIO);
 241 }
 242
 243 struct gb_connection *
 244 gb_connection_create(struct gb_bundle *bundle, u16 cport_id,
 245                      gb_request_handler_t handler)
 246 {
 247         struct gb_interface *intf = bundle->intf;
 248
 249         return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
 250                                      handler, 0);
 251 }
 252 EXPORT_SYMBOL_GPL(gb_connection_create);
 253
 254 struct gb_connection *
 255 gb_connection_create_flags(struct gb_bundle *bundle, u16 cport_id,
 256                            gb_request_handler_t handler,
 257                            unsigned long flags)
 258 {
 259         struct gb_interface *intf = bundle->intf;
 260
 261         if (WARN_ON_ONCE(flags & GB_CONNECTION_FLAG_CORE_MASK))
 262                 flags &= ~GB_CONNECTION_FLAG_CORE_MASK;
 263
 264         return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
 265                                      handler, flags);
 266 }
 267 EXPORT_SYMBOL_GPL(gb_connection_create_flags);
 268
 269 struct gb_connection *
 270 gb_connection_create_offloaded(struct gb_bundle *bundle, u16 cport_id,
 271                                unsigned long flags)
 272 {
 273         flags |= GB_CONNECTION_FLAG_OFFLOADED;
 274
 275         return gb_connection_create_flags(bundle, cport_id, NULL, flags);
 276 }
 277 EXPORT_SYMBOL_GPL(gb_connection_create_offloaded);
 278
 279 static int gb_connection_hd_cport_enable(struct gb_connection *connection)
 280 {
 281         struct gb_host_device *hd = connection->hd;
 282         int ret;
 283
 284         if (!hd->driver->cport_enable)
 285                 return 0;
 286
 287         ret = hd->driver->cport_enable(hd, connection->hd_cport_id,
 288                                        connection->flags);
 289         if (ret) {
 290                 dev_err(&hd->dev, "%s: failed to enable host cport: %d\n",
 291                         connection->name, ret);
 292                 return ret;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static void gb_connection_hd_cport_disable(struct gb_connection *connection)
 299 {
 300         struct gb_host_device *hd = connection->hd;
 301         int ret;
 302
 303         if (!hd->driver->cport_disable)
 304                 return;
 305
 306         ret = hd->driver->cport_disable(hd, connection->hd_cport_id);
 307         if (ret) {
 308                 dev_err(&hd->dev, "%s: failed to disable host cport: %d\n",
 309                         connection->name, ret);
 310         }
 311 }
 312
 313 static int gb_connection_hd_cport_connected(struct gb_connection *connection)
 314 {
 315         struct gb_host_device *hd = connection->hd;
 316         int ret;
 317
 318         if (!hd->driver->cport_connected)
 319                 return 0;
 320
 321         ret = hd->driver->cport_connected(hd, connection->hd_cport_id);
 322         if (ret) {
 323                 dev_err(&hd->dev, "%s: failed to set connected state: %d\n",
 324                         connection->name, ret);
 325                 return ret;
 326         }
 327
 328         return 0;
 329 }
 330
 331 static int gb_connection_hd_cport_flush(struct gb_connection *connection)
 332 {
 333         struct gb_host_device *hd = connection->hd;
 334         int ret;
 335
 336         if (!hd->driver->cport_flush)
 337                 return 0;
 338
 339         ret = hd->driver->cport_flush(hd, connection->hd_cport_id);
 340         if (ret) {
 341                 dev_err(&hd->dev, "%s: failed to flush host cport: %d\n",
 342                         connection->name, ret);
 343                 return ret;
 344         }
 345
 346         return 0;
 347 }
 348
 349 static int gb_connection_hd_cport_quiesce(struct gb_connection *connection)
 350 {
 351         struct gb_host_device *hd = connection->hd;
 352         size_t peer_space;
 353         int ret;
 354
 355         if (!hd->driver->cport_quiesce)
 356                 return 0;
 357
 358         peer_space = sizeof(struct gb_operation_msg_hdr) +
 359                         sizeof(struct gb_cport_shutdown_request);
 360
 361         if (connection->mode_switch)
 362                 peer_space += sizeof(struct gb_operation_msg_hdr);
 363
 364         ret = hd->driver->cport_quiesce(hd, connection->hd_cport_id,
 365                                         peer_space,
 366                                         GB_CONNECTION_CPORT_QUIESCE_TIMEOUT);
 367         if (ret) {
 368                 dev_err(&hd->dev, "%s: failed to quiesce host cport: %d\n",
 369                         connection->name, ret);
 370                 return ret;
 371         }
 372
 373         return 0;
 374 }
 375
 376 static int gb_connection_hd_cport_clear(struct gb_connection *connection)
 377 {
 378         struct gb_host_device *hd = connection->hd;
 379         int ret;
 380
 381         if (!hd->driver->cport_clear)
 382                 return 0;
 383
 384         ret = hd->driver->cport_clear(hd, connection->hd_cport_id);
 385         if (ret) {
 386                 dev_err(&hd->dev, "%s: failed to clear host cport: %d\n",
 387                         connection->name, ret);
 388                 return ret;
 389         }
 390
 391         return 0;
 392 }
 393
 394 /*
 395  * Request the SVC to create a connection from AP's cport to interface's
 396  * cport.
 397  */
 398 static int
 399 gb_connection_svc_connection_create(struct gb_connection *connection)
 400 {
 401         struct gb_host_device *hd = connection->hd;
 402         struct gb_interface *intf;
 403         u8 cport_flags;
 404         int ret;
 405
 406         if (gb_connection_is_static(connection))
 407                 return 0;
 408
 409         intf = connection->intf;
 410
 411         /*
 412          * Enable either E2EFC or CSD, unless no flow control is requested.
 413          */
 414         cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
 415         if (gb_connection_flow_control_disabled(connection)) {
 416                 cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
 417         } else if (gb_connection_e2efc_enabled(connection)) {
 418                 cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |
 419                                 GB_SVC_CPORT_FLAG_E2EFC;
 420         }
 421
 422         ret = gb_svc_connection_create(hd->svc,
 423                                        hd->svc->ap_intf_id,
 424                                        connection->hd_cport_id,
 425                                        intf->interface_id,
 426                                        connection->intf_cport_id,
 427                                        cport_flags);
 428         if (ret) {
 429                 dev_err(&connection->hd->dev,
 430                         "%s: failed to create svc connection: %d\n",
 431                         connection->name, ret);
 432                 return ret;
 433         }
 434
 435         return 0;
 436 }
 437
 438 static void
 439 gb_connection_svc_connection_destroy(struct gb_connection *connection)
 440 {
 441         if (gb_connection_is_static(connection))
 442                 return;
 443
 444         gb_svc_connection_destroy(connection->hd->svc,
 445                                   connection->hd->svc->ap_intf_id,
 446                                   connection->hd_cport_id,
 447                                   connection->intf->interface_id,
 448                                   connection->intf_cport_id);
 449 }
 450
 451 /* Inform Interface about active CPorts */
 452 static int gb_connection_control_connected(struct gb_connection *connection)
 453 {
 454         struct gb_control *control;
 455         u16 cport_id = connection->intf_cport_id;
 456         int ret;
 457
 458         if (gb_connection_is_static(connection))
 459                 return 0;
 460
 461         if (gb_connection_is_control(connection))
 462                 return 0;
 463
 464         control = connection->intf->control;
 465
 466         ret = gb_control_connected_operation(control, cport_id);
 467         if (ret) {
 468                 dev_err(&connection->bundle->dev,
 469                         "failed to connect cport: %d\n", ret);
 470                 return ret;
 471         }
 472
 473         return 0;
 474 }
 475
 476 static void
 477 gb_connection_control_disconnecting(struct gb_connection *connection)
 478 {
 479         struct gb_control *control;
 480         u16 cport_id = connection->intf_cport_id;
 481         int ret;
 482
 483         if (gb_connection_is_static(connection))
 484                 return;
 485
 486         control = connection->intf->control;
 487
 488         ret = gb_control_disconnecting_operation(control, cport_id);
 489         if (ret) {
 490                 dev_err(&connection->hd->dev,
 491                         "%s: failed to send disconnecting: %d\n",
 492                         connection->name, ret);
 493         }
 494 }
 495
 496 static void
 497 gb_connection_control_disconnected(struct gb_connection *connection)
 498 {
 499         struct gb_control *control;
 500         u16 cport_id = connection->intf_cport_id;
 501         int ret;
 502
 503         if (gb_connection_is_static(connection))
 504                 return;
 505
 506         control = connection->intf->control;
 507
 508         if (gb_connection_is_control(connection)) {
 509                 if (connection->mode_switch) {
 510                         ret = gb_control_mode_switch_operation(control);
 511                         if (ret) {
 512                                 /*
 513                                  * Allow mode switch to time out waiting for
 514                                  * mailbox event.
 515                                  */
 516                                 return;
 517                         }
 518                 }
 519
 520                 return;
 521         }
 522
 523         ret = gb_control_disconnected_operation(control, cport_id);
 524         if (ret) {
 525                 dev_warn(&connection->bundle->dev,
 526                          "failed to disconnect cport: %d\n", ret);
 527         }
 528 }
 529
 530 static int gb_connection_shutdown_operation(struct gb_connection *connection,
 531                                             u8 phase)
 532 {
 533         struct gb_cport_shutdown_request *req;
 534         struct gb_operation *operation;
 535         int ret;
 536
 537         operation = gb_operation_create_core(connection,
 538                                              GB_REQUEST_TYPE_CPORT_SHUTDOWN,
 539                                              sizeof(*req), 0, 0,
 540                                              GFP_KERNEL);
 541         if (!operation)
 542                 return -ENOMEM;
 543
 544         req = operation->request->payload;
 545         req->phase = phase;
 546
 547         ret = gb_operation_request_send_sync(operation);
 548
 549         gb_operation_put(operation);
 550
 551         return ret;
 552 }
 553
 554 static int gb_connection_cport_shutdown(struct gb_connection *connection,
 555                                         u8 phase)
 556 {
 557         struct gb_host_device *hd = connection->hd;
 558         const struct gb_hd_driver *drv = hd->driver;
 559         int ret;
 560
 561         if (gb_connection_is_static(connection))
 562                 return 0;
 563
 564         if (gb_connection_is_offloaded(connection)) {
 565                 if (!drv->cport_shutdown)
 566                         return 0;
 567
 568                 ret = drv->cport_shutdown(hd, connection->hd_cport_id, phase,
 569                                           GB_OPERATION_TIMEOUT_DEFAULT);
 570         } else {
 571                 ret = gb_connection_shutdown_operation(connection, phase);
 572         }
 573
 574         if (ret) {
 575                 dev_err(&hd->dev, "%s: failed to send cport shutdown (phase %d): %d\n",
 576                         connection->name, phase, ret);
 577                 return ret;
 578         }
 579
 580         return 0;
 581 }
 582
 583 static int
 584 gb_connection_cport_shutdown_phase_1(struct gb_connection *connection)
 585 {
 586         return gb_connection_cport_shutdown(connection, 1);
 587 }
 588
 589 static int
 590 gb_connection_cport_shutdown_phase_2(struct gb_connection *connection)
 591 {
 592         return gb_connection_cport_shutdown(connection, 2);
 593 }
 594
 595 /*
 596  * Cancel all active operations on a connection.
 597  *
 598  * Locking: Called with connection lock held and state set to DISABLED or
 599  * DISCONNECTING.
 600  */
 601 static void gb_connection_cancel_operations(struct gb_connection *connection,
 602                                             int errno)
 603         __must_hold(&connection->lock)
 604 {
 605         struct gb_operation *operation;
 606
 607         while (!list_empty(&connection->operations)) {
 608                 operation = list_last_entry(&connection->operations,
 609                                             struct gb_operation, links);
 610                 gb_operation_get(operation);
 611                 spin_unlock_irq(&connection->lock);
 612
 613                 if (gb_operation_is_incoming(operation))
 614                         gb_operation_cancel_incoming(operation, errno);
 615                 else
 616                         gb_operation_cancel(operation, errno);
 617
 618                 gb_operation_put(operation);
 619
 620                 spin_lock_irq(&connection->lock);
 621         }
 622 }
 623
 624 /*
 625  * Cancel all active incoming operations on a connection.
 626  *
 627  * Locking: Called with connection lock held and state set to ENABLED_TX.
 628  */
 629 static void
 630 gb_connection_flush_incoming_operations(struct gb_connection *connection,
 631                                         int errno)
 632         __must_hold(&connection->lock)
 633 {
 634         struct gb_operation *operation;
 635         bool incoming;
 636
 637         while (!list_empty(&connection->operations)) {
 638                 incoming = false;
 639                 list_for_each_entry(operation, &connection->operations,
 640                                     links) {
 641                         if (gb_operation_is_incoming(operation)) {
 642                                 gb_operation_get(operation);
 643                                 incoming = true;
 644                                 break;
 645                         }
 646                 }
 647
 648                 if (!incoming)
 649                         break;
 650
 651                 spin_unlock_irq(&connection->lock);
 652
 653                 /* FIXME: flush, not cancel? */
 654                 gb_operation_cancel_incoming(operation, errno);
 655                 gb_operation_put(operation);
 656
 657                 spin_lock_irq(&connection->lock);
 658         }
 659 }
 660
 661 /*
 662  * _gb_connection_enable() - enable a connection
 663  * @connection:         connection to enable
 664  * @rx:                 whether to enable incoming requests
 665  *
 666  * Connection-enable helper for DISABLED->ENABLED, DISABLED->ENABLED_TX, and
 667  * ENABLED_TX->ENABLED state transitions.
 668  *
 669  * Locking: Caller holds connection->mutex.
 670  */
 671 static int _gb_connection_enable(struct gb_connection *connection, bool rx)
 672 {
 673         int ret;
 674
 675         /* Handle ENABLED_TX -> ENABLED transitions. */
 676         if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
 677                 if (!(connection->handler && rx))
 678                         return 0;
 679
 680                 spin_lock_irq(&connection->lock);
 681                 connection->state = GB_CONNECTION_STATE_ENABLED;
 682                 spin_unlock_irq(&connection->lock);
 683
 684                 return 0;
 685         }
 686
 687         ret = gb_connection_hd_cport_enable(connection);
 688         if (ret)
 689                 return ret;
 690
 691         ret = gb_connection_svc_connection_create(connection);
 692         if (ret)
 693                 goto err_hd_cport_clear;
 694
 695         ret = gb_connection_hd_cport_connected(connection);
 696         if (ret)
 697                 goto err_svc_connection_destroy;
 698
 699         spin_lock_irq(&connection->lock);
 700         if (connection->handler && rx)
 701                 connection->state = GB_CONNECTION_STATE_ENABLED;
 702         else
 703                 connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 704         spin_unlock_irq(&connection->lock);
 705
 706         ret = gb_connection_control_connected(connection);
 707         if (ret)
 708                 goto err_control_disconnecting;
 709
 710         return 0;
 711
 712 err_control_disconnecting:
 713         spin_lock_irq(&connection->lock);
 714         connection->state = GB_CONNECTION_STATE_DISCONNECTING;
 715         gb_connection_cancel_operations(connection, -ESHUTDOWN);
 716         spin_unlock_irq(&connection->lock);
 717
 718         /* Transmit queue should already be empty. */
 719         gb_connection_hd_cport_flush(connection);
 720
 721         gb_connection_control_disconnecting(connection);
 722         gb_connection_cport_shutdown_phase_1(connection);
 723         gb_connection_hd_cport_quiesce(connection);
 724         gb_connection_cport_shutdown_phase_2(connection);
 725         gb_connection_control_disconnected(connection);
 726         connection->state = GB_CONNECTION_STATE_DISABLED;
 727 err_svc_connection_destroy:
 728         gb_connection_svc_connection_destroy(connection);
 729 err_hd_cport_clear:
 730         gb_connection_hd_cport_clear(connection);
 731
 732         gb_connection_hd_cport_disable(connection);
 733
 734         return ret;
 735 }
 736
 737 int gb_connection_enable(struct gb_connection *connection)
 738 {
 739         int ret = 0;
 740
 741         mutex_lock(&connection->mutex);
 742
 743         if (connection->state == GB_CONNECTION_STATE_ENABLED)
 744                 goto out_unlock;
 745
 746         ret = _gb_connection_enable(connection, true);
 747         if (!ret)
 748                 trace_gb_connection_enable(connection);
 749
 750 out_unlock:
 751         mutex_unlock(&connection->mutex);
 752
 753         return ret;
 754 }
 755 EXPORT_SYMBOL_GPL(gb_connection_enable);
 756
 757 int gb_connection_enable_tx(struct gb_connection *connection)
 758 {
 759         int ret = 0;
 760
 761         mutex_lock(&connection->mutex);
 762
 763         if (connection->state == GB_CONNECTION_STATE_ENABLED) {
 764                 ret = -EINVAL;
 765                 goto out_unlock;
 766         }
 767
 768         if (connection->state == GB_CONNECTION_STATE_ENABLED_TX)
 769                 goto out_unlock;
 770
 771         ret = _gb_connection_enable(connection, false);
 772         if (!ret)
 773                 trace_gb_connection_enable(connection);
 774
 775 out_unlock:
 776         mutex_unlock(&connection->mutex);
 777
 778         return ret;
 779 }
 780 EXPORT_SYMBOL_GPL(gb_connection_enable_tx);
 781
 782 void gb_connection_disable_rx(struct gb_connection *connection)
 783 {
 784         mutex_lock(&connection->mutex);
 785
 786         spin_lock_irq(&connection->lock);
 787         if (connection->state != GB_CONNECTION_STATE_ENABLED) {
 788                 spin_unlock_irq(&connection->lock);
 789                 goto out_unlock;
 790         }
 791         connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 792         gb_connection_flush_incoming_operations(connection, -ESHUTDOWN);
 793         spin_unlock_irq(&connection->lock);
 794
 795         trace_gb_connection_disable(connection);
 796
 797 out_unlock:
 798         mutex_unlock(&connection->mutex);
 799 }
 800 EXPORT_SYMBOL_GPL(gb_connection_disable_rx);
 801
 802 void gb_connection_mode_switch_prepare(struct gb_connection *connection)
 803 {
 804         connection->mode_switch = true;
 805 }
 806
 807 void gb_connection_mode_switch_complete(struct gb_connection *connection)
 808 {
 809         gb_connection_svc_connection_destroy(connection);
 810         gb_connection_hd_cport_clear(connection);
 811
 812         gb_connection_hd_cport_disable(connection);
 813
 814         connection->mode_switch = false;
 815 }
 816
 817 void gb_connection_disable(struct gb_connection *connection)
 818 {
 819         mutex_lock(&connection->mutex);
 820
 821         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 822                 goto out_unlock;
 823
 824         trace_gb_connection_disable(connection);
 825
 826         spin_lock_irq(&connection->lock);
 827         connection->state = GB_CONNECTION_STATE_DISCONNECTING;
 828         gb_connection_cancel_operations(connection, -ESHUTDOWN);
 829         spin_unlock_irq(&connection->lock);
 830
 831         gb_connection_hd_cport_flush(connection);
 832
 833         gb_connection_control_disconnecting(connection);
 834         gb_connection_cport_shutdown_phase_1(connection);
 835         gb_connection_hd_cport_quiesce(connection);
 836         gb_connection_cport_shutdown_phase_2(connection);
 837         gb_connection_control_disconnected(connection);
 838
 839         connection->state = GB_CONNECTION_STATE_DISABLED;
 840
 841         /* control-connection tear down is deferred when mode switching */
 842         if (!connection->mode_switch) {
 843                 gb_connection_svc_connection_destroy(connection);
 844                 gb_connection_hd_cport_clear(connection);
 845
 846                 gb_connection_hd_cport_disable(connection);
 847         }
 848
 849 out_unlock:
 850         mutex_unlock(&connection->mutex);
 851 }
 852 EXPORT_SYMBOL_GPL(gb_connection_disable);
 853
 854 /* Disable a connection without communicating with the remote end. */
 855 void gb_connection_disable_forced(struct gb_connection *connection)
 856 {
 857         mutex_lock(&connection->mutex);
 858
 859         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 860                 goto out_unlock;
 861
 862         trace_gb_connection_disable(connection);
 863
 864         spin_lock_irq(&connection->lock);
 865         connection->state = GB_CONNECTION_STATE_DISABLED;
 866         gb_connection_cancel_operations(connection, -ESHUTDOWN);
 867         spin_unlock_irq(&connection->lock);
 868
 869         gb_connection_hd_cport_flush(connection);
 870
 871         gb_connection_svc_connection_destroy(connection);
 872         gb_connection_hd_cport_clear(connection);
 873
 874         gb_connection_hd_cport_disable(connection);
 875 out_unlock:
 876         mutex_unlock(&connection->mutex);
 877 }
 878 EXPORT_SYMBOL_GPL(gb_connection_disable_forced);
 879
 880 /* Caller must have disabled the connection before destroying it. */
 881 void gb_connection_destroy(struct gb_connection *connection)
 882 {
 883         if (!connection)
 884                 return;
 885
 886         if (WARN_ON(connection->state != GB_CONNECTION_STATE_DISABLED))
 887                 gb_connection_disable(connection);
 888
 889         mutex_lock(&gb_connection_mutex);
 890
 891         spin_lock_irq(&gb_connections_lock);
 892         list_del(&connection->bundle_links);
 893         list_del(&connection->hd_links);
 894         spin_unlock_irq(&gb_connections_lock);
 895
 896         destroy_workqueue(connection->wq);
 897
 898         gb_hd_cport_release(connection->hd, connection->hd_cport_id);
 899         connection->hd_cport_id = CPORT_ID_BAD;
 900
 901         mutex_unlock(&gb_connection_mutex);
 902
 903         gb_connection_put(connection);
 904 }
 905 EXPORT_SYMBOL_GPL(gb_connection_destroy);
 906
 907 void gb_connection_latency_tag_enable(struct gb_connection *connection)
 908 {
 909         struct gb_host_device *hd = connection->hd;
 910         int ret;
 911
 912         if (!hd->driver->latency_tag_enable)
 913                 return;
 914
 915         ret = hd->driver->latency_tag_enable(hd, connection->hd_cport_id);
 916         if (ret) {
 917                 dev_err(&connection->hd->dev,
 918                         "%s: failed to enable latency tag: %d\n",
 919                         connection->name, ret);
 920         }
 921 }
 922 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_enable);
 923
 924 void gb_connection_latency_tag_disable(struct gb_connection *connection)
 925 {
 926         struct gb_host_device *hd = connection->hd;
 927         int ret;
 928
 929         if (!hd->driver->latency_tag_disable)
 930                 return;
 931
 932         ret = hd->driver->latency_tag_disable(hd, connection->hd_cport_id);
 933         if (ret) {
 934                 dev_err(&connection->hd->dev,
 935                         "%s: failed to disable latency tag: %d\n",
 936                         connection->name, ret);
 937         }
 938 }
 939 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_disable);