drivers/staging/greybus/connection.c

   1 /*
   2  * Greybus connections
   3  *
   4  * Copyright 2014 Google Inc.
   5  * Copyright 2014 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include <linux/workqueue.h>
  11
  12 #include "greybus.h"
  13 #include "greybus_trace.h"
  14
  15
  16 static void gb_connection_kref_release(struct kref *kref);
  17
  18
  19 static DEFINE_SPINLOCK(gb_connections_lock);
  20 static DEFINE_MUTEX(gb_connection_mutex);
  21
  22
  23 /* Caller holds gb_connection_mutex. */
  24 static bool gb_connection_cport_in_use(struct gb_interface *intf, u16 cport_id)
  25 {
  26         struct gb_host_device *hd = intf->hd;
  27         struct gb_connection *connection;
  28
  29         list_for_each_entry(connection, &hd->connections, hd_links) {
  30                 if (connection->intf == intf &&
  31                                 connection->intf_cport_id == cport_id)
  32                         return true;
  33         }
  34
  35         return false;
  36 }
  37
  38 static void gb_connection_get(struct gb_connection *connection)
  39 {
  40         kref_get(&connection->kref);
  41
  42         trace_gb_connection_get(connection);
  43 }
  44
  45 static void gb_connection_put(struct gb_connection *connection)
  46 {
  47         trace_gb_connection_put(connection);
  48
  49         kref_put(&connection->kref, gb_connection_kref_release);
  50 }
  51
  52 /*
  53  * Returns a reference-counted pointer to the connection if found.
  54  */
  55 static struct gb_connection *
  56 gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
  57 {
  58         struct gb_connection *connection;
  59         unsigned long flags;
  60
  61         spin_lock_irqsave(&gb_connections_lock, flags);
  62         list_for_each_entry(connection, &hd->connections, hd_links)
  63                 if (connection->hd_cport_id == cport_id) {
  64                         gb_connection_get(connection);
  65                         goto found;
  66                 }
  67         connection = NULL;
  68 found:
  69         spin_unlock_irqrestore(&gb_connections_lock, flags);
  70
  71         return connection;
  72 }
  73
  74 /*
  75  * Callback from the host driver to let us know that data has been
  76  * received on the bundle.
  77  */
  78 void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
  79                         u8 *data, size_t length)
  80 {
  81         struct gb_connection *connection;
  82
  83         trace_gb_hd_in(hd);
  84
  85         connection = gb_connection_hd_find(hd, cport_id);
  86         if (!connection) {
  87                 dev_err(&hd->dev,
  88                         "nonexistent connection (%zu bytes dropped)\n", length);
  89                 return;
  90         }
  91         gb_connection_recv(connection, data, length);
  92         gb_connection_put(connection);
  93 }
  94 EXPORT_SYMBOL_GPL(greybus_data_rcvd);
  95
  96 static void gb_connection_kref_release(struct kref *kref)
  97 {
  98         struct gb_connection *connection;
  99
 100         connection = container_of(kref, struct gb_connection, kref);
 101
 102         trace_gb_connection_release(connection);
 103
 104         kfree(connection);
 105 }
 106
 107 static void gb_connection_init_name(struct gb_connection *connection)
 108 {
 109         u16 hd_cport_id = connection->hd_cport_id;
 110         u16 cport_id = 0;
 111         u8 intf_id = 0;
 112
 113         if (connection->intf) {
 114                 intf_id = connection->intf->interface_id;
 115                 cport_id = connection->intf_cport_id;
 116         }
 117
 118         snprintf(connection->name, sizeof(connection->name),
 119                         "%u/%u:%u", hd_cport_id, intf_id, cport_id);
 120 }
 121
 122 /*
 123  * _gb_connection_create() - create a Greybus connection
 124  * @hd:                 host device of the connection
 125  * @hd_cport_id:        host-device cport id, or -1 for dynamic allocation
 126  * @intf:               remote interface, or NULL for static connections
 127  * @bundle:             remote-interface bundle (may be NULL)
 128  * @cport_id:           remote-interface cport id, or 0 for static connections
 129  * @handler:            request handler (may be NULL)
 130  * @flags:              connection flags
 131  *
 132  * Create a Greybus connection, representing the bidirectional link
 133  * between a CPort on a (local) Greybus host device and a CPort on
 134  * another Greybus interface.
 135  *
 136  * A connection also maintains the state of operations sent over the
 137  * connection.
 138  *
 139  * Serialised against concurrent create and destroy using the
 140  * gb_connection_mutex.
 141  *
 142  * Return: A pointer to the new connection if successful, or an ERR_PTR
 143  * otherwise.
 144  */
 145 static struct gb_connection *
 146 _gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 147                                 struct gb_interface *intf,
 148                                 struct gb_bundle *bundle, int cport_id,
 149                                 gb_request_handler_t handler,
 150                                 unsigned long flags)
 151 {
 152         struct gb_connection *connection;
 153         unsigned long irqflags;
 154         int ret;
 155
 156         mutex_lock(&gb_connection_mutex);
 157
 158         if (intf && gb_connection_cport_in_use(intf, cport_id)) {
 159                 dev_err(&intf->dev, "cport %u already in use\n", cport_id);
 160                 ret = -EBUSY;
 161                 goto err_unlock;
 162         }
 163
 164         ret = gb_hd_cport_allocate(hd, hd_cport_id, flags);
 165         if (ret < 0) {
 166                 dev_err(&hd->dev, "failed to allocate cport: %d\n", ret);
 167                 goto err_unlock;
 168         }
 169         hd_cport_id = ret;
 170
 171         connection = kzalloc(sizeof(*connection), GFP_KERNEL);
 172         if (!connection) {
 173                 ret = -ENOMEM;
 174                 goto err_hd_cport_release;
 175         }
 176
 177         connection->hd_cport_id = hd_cport_id;
 178         connection->intf_cport_id = cport_id;
 179         connection->hd = hd;
 180         connection->intf = intf;
 181         connection->bundle = bundle;
 182         connection->handler = handler;
 183         connection->flags = flags;
 184         if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
 185                 connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
 186         connection->state = GB_CONNECTION_STATE_DISABLED;
 187
 188         atomic_set(&connection->op_cycle, 0);
 189         mutex_init(&connection->mutex);
 190         spin_lock_init(&connection->lock);
 191         INIT_LIST_HEAD(&connection->operations);
 192
 193         connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
 194                                          dev_name(&hd->dev), hd_cport_id);
 195         if (!connection->wq) {
 196                 ret = -ENOMEM;
 197                 goto err_free_connection;
 198         }
 199
 200         kref_init(&connection->kref);
 201
 202         gb_connection_init_name(connection);
 203
 204         spin_lock_irqsave(&gb_connections_lock, irqflags);
 205         list_add(&connection->hd_links, &hd->connections);
 206
 207         if (bundle)
 208                 list_add(&connection->bundle_links, &bundle->connections);
 209         else
 210                 INIT_LIST_HEAD(&connection->bundle_links);
 211
 212         spin_unlock_irqrestore(&gb_connections_lock, irqflags);
 213
 214         mutex_unlock(&gb_connection_mutex);
 215
 216         trace_gb_connection_create(connection);
 217
 218         return connection;
 219
 220 err_free_connection:
 221         kfree(connection);
 222 err_hd_cport_release:
 223         gb_hd_cport_release(hd, hd_cport_id);
 224 err_unlock:
 225         mutex_unlock(&gb_connection_mutex);
 226
 227         return ERR_PTR(ret);
 228 }
 229
 230 struct gb_connection *
 231 gb_connection_create_static(struct gb_host_device *hd, u16 hd_cport_id,
 232                                         gb_request_handler_t handler)
 233 {
 234         return _gb_connection_create(hd, hd_cport_id, NULL, NULL, 0, handler,
 235                                         GB_CONNECTION_FLAG_HIGH_PRIO);
 236 }
 237
 238 struct gb_connection *
 239 gb_connection_create_control(struct gb_interface *intf)
 240 {
 241         return _gb_connection_create(intf->hd, -1, intf, NULL, 0, NULL,
 242                                         GB_CONNECTION_FLAG_CONTROL |
 243                                         GB_CONNECTION_FLAG_HIGH_PRIO);
 244 }
 245
 246 struct gb_connection *
 247 gb_connection_create(struct gb_bundle *bundle, u16 cport_id,
 248                                         gb_request_handler_t handler)
 249 {
 250         struct gb_interface *intf = bundle->intf;
 251
 252         return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
 253                                         handler, 0);
 254 }
 255 EXPORT_SYMBOL_GPL(gb_connection_create);
 256
 257 struct gb_connection *
 258 gb_connection_create_flags(struct gb_bundle *bundle, u16 cport_id,
 259                                         gb_request_handler_t handler,
 260                                         unsigned long flags)
 261 {
 262         struct gb_interface *intf = bundle->intf;
 263
 264         if (WARN_ON_ONCE(flags & GB_CONNECTION_FLAG_CORE_MASK))
 265                 flags &= ~GB_CONNECTION_FLAG_CORE_MASK;
 266
 267         return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
 268                                         handler, flags);
 269 }
 270 EXPORT_SYMBOL_GPL(gb_connection_create_flags);
 271
 272 struct gb_connection *
 273 gb_connection_create_offloaded(struct gb_bundle *bundle, u16 cport_id,
 274                                         unsigned long flags)
 275 {
 276         flags |= GB_CONNECTION_FLAG_OFFLOADED;
 277
 278         return gb_connection_create_flags(bundle, cport_id, NULL, flags);
 279 }
 280 EXPORT_SYMBOL_GPL(gb_connection_create_offloaded);
 281
 282 static int gb_connection_hd_cport_enable(struct gb_connection *connection)
 283 {
 284         struct gb_host_device *hd = connection->hd;
 285         int ret;
 286
 287         if (!hd->driver->cport_enable)
 288                 return 0;
 289
 290         ret = hd->driver->cport_enable(hd, connection->hd_cport_id,
 291                                         connection->flags);
 292         if (ret) {
 293                 dev_err(&hd->dev, "%s: failed to enable host cport: %d\n",
 294                                 connection->name, ret);
 295                 return ret;
 296         }
 297
 298         return 0;
 299 }
 300
 301 static void gb_connection_hd_cport_disable(struct gb_connection *connection)
 302 {
 303         struct gb_host_device *hd = connection->hd;
 304         int ret;
 305
 306         if (!hd->driver->cport_disable)
 307                 return;
 308
 309         ret = hd->driver->cport_disable(hd, connection->hd_cport_id);
 310         if (ret) {
 311                 dev_err(&hd->dev, "%s: failed to disable host cport: %d\n",
 312                                 connection->name, ret);
 313         }
 314 }
 315
 316 static int gb_connection_hd_cport_flush(struct gb_connection *connection)
 317 {
 318         struct gb_host_device *hd = connection->hd;
 319         int ret;
 320
 321         if (!hd->driver->cport_flush)
 322                 return 0;
 323
 324         ret = hd->driver->cport_flush(hd, connection->hd_cport_id);
 325         if (ret) {
 326                 dev_err(&hd->dev, "%s: failed to flush host cport: %d\n",
 327                                 connection->name, ret);
 328                 return ret;
 329         }
 330
 331         return 0;
 332 }
 333
 334 static int
 335 gb_connection_hd_cport_features_enable(struct gb_connection *connection)
 336 {
 337         struct gb_host_device *hd = connection->hd;
 338         int ret;
 339
 340         if (!hd->driver->cport_features_enable)
 341                 return 0;
 342
 343         ret = hd->driver->cport_features_enable(hd, connection->hd_cport_id);
 344         if (ret) {
 345                 dev_err(&hd->dev, "%s: failed to enable CPort features: %d\n",
 346                         connection->name, ret);
 347                 return ret;
 348         }
 349
 350         return 0;
 351 }
 352
 353 static void
 354 gb_connection_hd_cport_features_disable(struct gb_connection *connection)
 355 {
 356         struct gb_host_device *hd = connection->hd;
 357
 358         if (!hd->driver->cport_features_disable)
 359                 return;
 360
 361         hd->driver->cport_features_disable(hd, connection->hd_cport_id);
 362 }
 363
 364 /*
 365  * Request the SVC to create a connection from AP's cport to interface's
 366  * cport.
 367  */
 368 static int
 369 gb_connection_svc_connection_create(struct gb_connection *connection)
 370 {
 371         struct gb_host_device *hd = connection->hd;
 372         struct gb_interface *intf;
 373         u8 cport_flags;
 374         int ret;
 375
 376         if (gb_connection_is_static(connection))
 377                 return 0;
 378
 379         intf = connection->intf;
 380
 381         /*
 382          * Enable either E2EFC or CSD, unless no flow control is requested.
 383          */
 384         cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
 385         if (gb_connection_flow_control_disabled(connection)) {
 386                 cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
 387         } else if (gb_connection_e2efc_enabled(connection)) {
 388                 cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |
 389                                 GB_SVC_CPORT_FLAG_E2EFC;
 390         }
 391
 392         ret = gb_svc_connection_create(hd->svc,
 393                         hd->svc->ap_intf_id,
 394                         connection->hd_cport_id,
 395                         intf->interface_id,
 396                         connection->intf_cport_id,
 397                         cport_flags);
 398         if (ret) {
 399                 dev_err(&connection->hd->dev,
 400                         "%s: failed to create svc connection: %d\n",
 401                         connection->name, ret);
 402                 return ret;
 403         }
 404
 405         return 0;
 406 }
 407
 408 static void
 409 gb_connection_svc_connection_destroy(struct gb_connection *connection)
 410 {
 411         if (gb_connection_is_static(connection))
 412                 return;
 413
 414         gb_svc_connection_destroy(connection->hd->svc,
 415                                   connection->hd->svc->ap_intf_id,
 416                                   connection->hd_cport_id,
 417                                   connection->intf->interface_id,
 418                                   connection->intf_cport_id);
 419 }
 420
 421 static void
 422 gb_connection_svc_connection_quiescing(struct gb_connection *connection)
 423 {
 424         struct gb_host_device *hd = connection->hd;
 425
 426         if (gb_connection_is_static(connection))
 427                 return;
 428
 429         gb_svc_connection_quiescing(hd->svc,
 430                                         hd->svc->ap_intf_id,
 431                                         connection->hd_cport_id,
 432                                         connection->intf->interface_id,
 433                                         connection->intf_cport_id);
 434 }
 435
 436 /* Inform Interface about active CPorts */
 437 static int gb_connection_control_connected(struct gb_connection *connection)
 438 {
 439         struct gb_control *control;
 440         u16 cport_id = connection->intf_cport_id;
 441         int ret;
 442
 443         if (gb_connection_is_static(connection))
 444                 return 0;
 445
 446         /*
 447          * HACK: Suppress connected request for the offloaded camera
 448          * connection as it is currently not supported by firmware. Note that
 449          * the corresponding non-fatal disconnected event is still sent.
 450          */
 451         if (gb_connection_is_offloaded(connection) &&
 452                         connection->flags & GB_CONNECTION_FLAG_CDSI1) {
 453                 return 0;
 454         }
 455
 456         if (gb_connection_is_control(connection))
 457                 return 0;
 458
 459         control = connection->intf->control;
 460
 461         ret = gb_control_connected_operation(control, cport_id);
 462         if (ret) {
 463                 dev_err(&connection->bundle->dev,
 464                         "failed to connect cport: %d\n", ret);
 465                 return ret;
 466         }
 467
 468         return 0;
 469 }
 470
 471 static void
 472 gb_connection_control_disconnecting(struct gb_connection *connection)
 473 {
 474         struct gb_control *control;
 475         u16 cport_id = connection->intf_cport_id;
 476         int ret;
 477
 478         if (gb_connection_is_static(connection))
 479                 return;
 480
 481         control = connection->intf->control;
 482
 483         ret = gb_control_disconnecting_operation(control, cport_id);
 484         if (ret) {
 485                 dev_err(&connection->hd->dev,
 486                                 "%s: failed to send disconnecting: %d\n",
 487                                 connection->name, ret);
 488         }
 489 }
 490
 491 static void
 492 gb_connection_control_disconnected(struct gb_connection *connection)
 493 {
 494         struct gb_control *control;
 495         u16 cport_id = connection->intf_cport_id;
 496         int ret;
 497
 498         if (gb_connection_is_static(connection))
 499                 return;
 500
 501         control = connection->intf->control;
 502
 503         if (gb_connection_is_control(connection)) {
 504                 if (connection->mode_switch) {
 505                         ret = gb_control_mode_switch_operation(control);
 506                         if (ret) {
 507                                 /*
 508                                  * Allow mode switch to time out waiting for
 509                                  * mailbox event.
 510                                  */
 511                                 return;
 512                         }
 513                 }
 514
 515                 return;
 516         }
 517
 518         ret = gb_control_disconnected_operation(control, cport_id);
 519         if (ret) {
 520                 dev_warn(&connection->bundle->dev,
 521                          "failed to disconnect cport: %d\n", ret);
 522         }
 523 }
 524
 525 static int gb_connection_ping_operation(struct gb_connection *connection)
 526 {
 527         struct gb_operation *operation;
 528         int ret;
 529
 530         operation = gb_operation_create_core(connection,
 531                                                 GB_REQUEST_TYPE_PING,
 532                                                 0, 0, 0,
 533                                                 GFP_KERNEL);
 534         if (!operation)
 535                 return -ENOMEM;
 536
 537         ret = gb_operation_request_send_sync(operation);
 538
 539         gb_operation_put(operation);
 540
 541         return ret;
 542 }
 543
 544 static int gb_connection_ping(struct gb_connection *connection)
 545 {
 546         struct gb_host_device *hd = connection->hd;
 547         int ret;
 548
 549         if (gb_connection_is_static(connection))
 550                 return 0;
 551
 552         if (gb_connection_is_offloaded(connection)) {
 553                 if (!hd->driver->cport_ping)
 554                         return 0;
 555
 556                 ret = hd->driver->cport_ping(hd, connection->intf_cport_id);
 557         } else {
 558                 ret = gb_connection_ping_operation(connection);
 559         }
 560
 561         if (ret) {
 562                 dev_err(&hd->dev, "%s: failed to send ping: %d\n",
 563                                 connection->name, ret);
 564                 return ret;
 565         }
 566
 567         return 0;
 568 }
 569
 570 /*
 571  * Cancel all active operations on a connection.
 572  *
 573  * Locking: Called with connection lock held and state set to DISABLED or
 574  * DISCONNECTING.
 575  */
 576 static void gb_connection_cancel_operations(struct gb_connection *connection,
 577                                                 int errno, unsigned long *flags)
 578         __must_hold(&connection->lock)
 579 {
 580         struct gb_operation *operation;
 581
 582         while (!list_empty(&connection->operations)) {
 583                 operation = list_last_entry(&connection->operations,
 584                                                 struct gb_operation, links);
 585                 gb_operation_get(operation);
 586                 spin_unlock_irqrestore(&connection->lock, *flags);
 587
 588                 if (gb_operation_is_incoming(operation))
 589                         gb_operation_cancel_incoming(operation, errno);
 590                 else
 591                         gb_operation_cancel(operation, errno);
 592
 593                 gb_operation_put(operation);
 594
 595                 spin_lock_irqsave(&connection->lock, *flags);
 596         }
 597 }
 598
 599 /*
 600  * Cancel all active incoming operations on a connection.
 601  *
 602  * Locking: Called with connection lock held and state set to ENABLED_TX.
 603  */
 604 static void
 605 gb_connection_flush_incoming_operations(struct gb_connection *connection,
 606                                                 int errno, unsigned long *flags)
 607         __must_hold(&connection->lock)
 608 {
 609         struct gb_operation *operation;
 610         bool incoming;
 611
 612         while (!list_empty(&connection->operations)) {
 613                 incoming = false;
 614                 list_for_each_entry(operation, &connection->operations,
 615                                                                 links) {
 616                         if (gb_operation_is_incoming(operation)) {
 617                                 gb_operation_get(operation);
 618                                 incoming = true;
 619                                 break;
 620                         }
 621                 }
 622
 623                 if (!incoming)
 624                         break;
 625
 626                 spin_unlock_irqrestore(&connection->lock, *flags);
 627
 628                 /* FIXME: flush, not cancel? */
 629                 gb_operation_cancel_incoming(operation, errno);
 630                 gb_operation_put(operation);
 631
 632                 spin_lock_irqsave(&connection->lock, *flags);
 633         }
 634 }
 635
 636 /*
 637  * _gb_connection_enable() - enable a connection
 638  * @connection:         connection to enable
 639  * @rx:                 whether to enable incoming requests
 640  *
 641  * Connection-enable helper for DISABLED->ENABLED, DISABLED->ENABLED_TX, and
 642  * ENABLED_TX->ENABLED state transitions.
 643  *
 644  * Locking: Caller holds connection->mutex.
 645  */
 646 static int _gb_connection_enable(struct gb_connection *connection, bool rx)
 647 {
 648         int ret;
 649         unsigned long flags;
 650
 651         /* Handle ENABLED_TX -> ENABLED transitions. */
 652         if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
 653                 if (!(connection->handler && rx))
 654                         return 0;
 655
 656                 spin_lock_irqsave(&connection->lock, flags);
 657                 connection->state = GB_CONNECTION_STATE_ENABLED;
 658                 spin_unlock_irqrestore(&connection->lock, flags);
 659
 660                 return 0;
 661         }
 662
 663         ret = gb_connection_hd_cport_enable(connection);
 664         if (ret)
 665                 return ret;
 666
 667         ret = gb_connection_svc_connection_create(connection);
 668         if (ret)
 669                 goto err_hd_cport_disable;
 670
 671         ret = gb_connection_hd_cport_features_enable(connection);
 672         if (ret)
 673                 goto err_svc_connection_destroy;
 674
 675         spin_lock_irqsave(&connection->lock, flags);
 676         if (connection->handler && rx)
 677                 connection->state = GB_CONNECTION_STATE_ENABLED;
 678         else
 679                 connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 680         spin_unlock_irqrestore(&connection->lock, flags);
 681
 682         ret = gb_connection_control_connected(connection);
 683         if (ret)
 684                 goto err_control_disconnecting;
 685
 686         return 0;
 687
 688 err_control_disconnecting:
 689         gb_connection_control_disconnecting(connection);
 690
 691         spin_lock_irqsave(&connection->lock, flags);
 692         connection->state = GB_CONNECTION_STATE_DISCONNECTING;
 693         gb_connection_cancel_operations(connection, -ESHUTDOWN, &flags);
 694         spin_unlock_irqrestore(&connection->lock, flags);
 695
 696         /* Transmit queue should already be empty. */
 697         gb_connection_hd_cport_flush(connection);
 698
 699         gb_connection_ping(connection);
 700         gb_connection_hd_cport_features_disable(connection);
 701         gb_connection_svc_connection_quiescing(connection);
 702         gb_connection_ping(connection);
 703         gb_connection_control_disconnected(connection);
 704         connection->state = GB_CONNECTION_STATE_DISABLED;
 705 err_svc_connection_destroy:
 706         gb_connection_svc_connection_destroy(connection);
 707 err_hd_cport_disable:
 708         gb_connection_hd_cport_disable(connection);
 709
 710         return ret;
 711 }
 712
 713 int gb_connection_enable(struct gb_connection *connection)
 714 {
 715         int ret = 0;
 716
 717         mutex_lock(&connection->mutex);
 718
 719         if (connection->state == GB_CONNECTION_STATE_ENABLED)
 720                 goto out_unlock;
 721
 722         ret = _gb_connection_enable(connection, true);
 723         if (!ret)
 724                 trace_gb_connection_enable(connection);
 725
 726 out_unlock:
 727         mutex_unlock(&connection->mutex);
 728
 729         return ret;
 730 }
 731 EXPORT_SYMBOL_GPL(gb_connection_enable);
 732
 733 int gb_connection_enable_tx(struct gb_connection *connection)
 734 {
 735         int ret = 0;
 736
 737         mutex_lock(&connection->mutex);
 738
 739         if (connection->state == GB_CONNECTION_STATE_ENABLED) {
 740                 ret = -EINVAL;
 741                 goto out_unlock;
 742         }
 743
 744         if (connection->state == GB_CONNECTION_STATE_ENABLED_TX)
 745                 goto out_unlock;
 746
 747         ret = _gb_connection_enable(connection, false);
 748         if (!ret)
 749                 trace_gb_connection_enable(connection);
 750
 751 out_unlock:
 752         mutex_unlock(&connection->mutex);
 753
 754         return ret;
 755 }
 756 EXPORT_SYMBOL_GPL(gb_connection_enable_tx);
 757
 758 void gb_connection_disable_rx(struct gb_connection *connection)
 759 {
 760         unsigned long flags;
 761
 762         mutex_lock(&connection->mutex);
 763
 764         spin_lock_irqsave(&connection->lock, flags);
 765         if (connection->state != GB_CONNECTION_STATE_ENABLED) {
 766                 spin_unlock_irqrestore(&connection->lock, flags);
 767                 goto out_unlock;
 768         }
 769         connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 770         gb_connection_flush_incoming_operations(connection, -ESHUTDOWN, &flags);
 771         spin_unlock_irqrestore(&connection->lock, flags);
 772
 773         trace_gb_connection_disable(connection);
 774
 775 out_unlock:
 776         mutex_unlock(&connection->mutex);
 777 }
 778 EXPORT_SYMBOL_GPL(gb_connection_disable_rx);
 779
 780 void gb_connection_mode_switch_prepare(struct gb_connection *connection)
 781 {
 782         connection->mode_switch = true;
 783 }
 784
 785 void gb_connection_mode_switch_complete(struct gb_connection *connection)
 786 {
 787         gb_connection_svc_connection_destroy(connection);
 788         gb_connection_hd_cport_disable(connection);
 789         connection->mode_switch = false;
 790 }
 791
 792 void gb_connection_disable(struct gb_connection *connection)
 793 {
 794         unsigned long flags;
 795
 796         mutex_lock(&connection->mutex);
 797
 798         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 799                 goto out_unlock;
 800
 801         trace_gb_connection_disable(connection);
 802
 803         gb_connection_control_disconnecting(connection);
 804
 805         spin_lock_irqsave(&connection->lock, flags);
 806         connection->state = GB_CONNECTION_STATE_DISCONNECTING;
 807         gb_connection_cancel_operations(connection, -ESHUTDOWN, &flags);
 808         spin_unlock_irqrestore(&connection->lock, flags);
 809
 810         gb_connection_hd_cport_flush(connection);
 811
 812         gb_connection_ping(connection);
 813         gb_connection_hd_cport_features_disable(connection);
 814         gb_connection_svc_connection_quiescing(connection);
 815         gb_connection_ping(connection);
 816
 817         gb_connection_control_disconnected(connection);
 818
 819         connection->state = GB_CONNECTION_STATE_DISABLED;
 820
 821         /* control-connection tear down is deferred when mode switching */
 822         if (!connection->mode_switch) {
 823                 gb_connection_svc_connection_destroy(connection);
 824                 gb_connection_hd_cport_disable(connection);
 825         }
 826
 827 out_unlock:
 828         mutex_unlock(&connection->mutex);
 829 }
 830 EXPORT_SYMBOL_GPL(gb_connection_disable);
 831
 832 /* Disable a connection without communicating with the remote end. */
 833 void gb_connection_disable_forced(struct gb_connection *connection)
 834 {
 835         unsigned long flags;
 836
 837         mutex_lock(&connection->mutex);
 838
 839         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 840                 goto out_unlock;
 841
 842         trace_gb_connection_disable(connection);
 843
 844         spin_lock_irqsave(&connection->lock, flags);
 845         connection->state = GB_CONNECTION_STATE_DISABLED;
 846         gb_connection_cancel_operations(connection, -ESHUTDOWN, &flags);
 847         spin_unlock_irqrestore(&connection->lock, flags);
 848
 849         gb_connection_hd_cport_flush(connection);
 850         gb_connection_hd_cport_features_disable(connection);
 851         gb_connection_svc_connection_destroy(connection);
 852         gb_connection_hd_cport_disable(connection);
 853
 854 out_unlock:
 855         mutex_unlock(&connection->mutex);
 856 }
 857 EXPORT_SYMBOL_GPL(gb_connection_disable_forced);
 858
 859 /* Caller must have disabled the connection before destroying it. */
 860 void gb_connection_destroy(struct gb_connection *connection)
 861 {
 862         unsigned long flags;
 863
 864         if (!connection)
 865                 return;
 866
 867         if (WARN_ON(connection->state != GB_CONNECTION_STATE_DISABLED))
 868                 gb_connection_disable(connection);
 869
 870         mutex_lock(&gb_connection_mutex);
 871
 872         spin_lock_irqsave(&gb_connections_lock, flags);
 873         list_del(&connection->bundle_links);
 874         list_del(&connection->hd_links);
 875         spin_unlock_irqrestore(&gb_connections_lock, flags);
 876
 877         destroy_workqueue(connection->wq);
 878
 879         gb_hd_cport_release(connection->hd, connection->hd_cport_id);
 880         connection->hd_cport_id = CPORT_ID_BAD;
 881
 882         mutex_unlock(&gb_connection_mutex);
 883
 884         gb_connection_put(connection);
 885 }
 886 EXPORT_SYMBOL_GPL(gb_connection_destroy);
 887
 888 void gb_connection_latency_tag_enable(struct gb_connection *connection)
 889 {
 890         struct gb_host_device *hd = connection->hd;
 891         int ret;
 892
 893         if (!hd->driver->latency_tag_enable)
 894                 return;
 895
 896         ret = hd->driver->latency_tag_enable(hd, connection->hd_cport_id);
 897         if (ret) {
 898                 dev_err(&connection->hd->dev,
 899                         "%s: failed to enable latency tag: %d\n",
 900                         connection->name, ret);
 901         }
 902 }
 903 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_enable);
 904
 905 void gb_connection_latency_tag_disable(struct gb_connection *connection)
 906 {
 907         struct gb_host_device *hd = connection->hd;
 908         int ret;
 909
 910         if (!hd->driver->latency_tag_disable)
 911                 return;
 912
 913         ret = hd->driver->latency_tag_disable(hd, connection->hd_cport_id);
 914         if (ret) {
 915                 dev_err(&connection->hd->dev,
 916                         "%s: failed to disable latency tag: %d\n",
 917                         connection->name, ret);
 918         }
 919 }
 920 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_disable);