drivers/media/mc/mc-entity.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Media entity
   4  *
   5  * Copyright (C) 2010 Nokia Corporation
   6  *
   7  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   8  *           Sakari Ailus <sakari.ailus@iki.fi>
   9  */
  10
  11 #include <linux/bitmap.h>
  12 #include <linux/property.h>
  13 #include <linux/slab.h>
  14 #include <media/media-entity.h>
  15 #include <media/media-device.h>
  16
  17 static inline const char *gobj_type(enum media_gobj_type type)
  18 {
  19         switch (type) {
  20         case MEDIA_GRAPH_ENTITY:
  21                 return "entity";
  22         case MEDIA_GRAPH_PAD:
  23                 return "pad";
  24         case MEDIA_GRAPH_LINK:
  25                 return "link";
  26         case MEDIA_GRAPH_INTF_DEVNODE:
  27                 return "intf-devnode";
  28         default:
  29                 return "unknown";
  30         }
  31 }
  32
  33 static inline const char *intf_type(struct media_interface *intf)
  34 {
  35         switch (intf->type) {
  36         case MEDIA_INTF_T_DVB_FE:
  37                 return "dvb-frontend";
  38         case MEDIA_INTF_T_DVB_DEMUX:
  39                 return "dvb-demux";
  40         case MEDIA_INTF_T_DVB_DVR:
  41                 return "dvb-dvr";
  42         case MEDIA_INTF_T_DVB_CA:
  43                 return  "dvb-ca";
  44         case MEDIA_INTF_T_DVB_NET:
  45                 return "dvb-net";
  46         case MEDIA_INTF_T_V4L_VIDEO:
  47                 return "v4l-video";
  48         case MEDIA_INTF_T_V4L_VBI:
  49                 return "v4l-vbi";
  50         case MEDIA_INTF_T_V4L_RADIO:
  51                 return "v4l-radio";
  52         case MEDIA_INTF_T_V4L_SUBDEV:
  53                 return "v4l-subdev";
  54         case MEDIA_INTF_T_V4L_SWRADIO:
  55                 return "v4l-swradio";
  56         case MEDIA_INTF_T_V4L_TOUCH:
  57                 return "v4l-touch";
  58         default:
  59                 return "unknown-intf";
  60         }
  61 };
  62
  63 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  64                                           int idx_max)
  65 {
  66         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  67         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  68                                  GFP_KERNEL);
  69         if (!ent_enum->bmap)
  70                 return -ENOMEM;
  71
  72         bitmap_zero(ent_enum->bmap, idx_max);
  73         ent_enum->idx_max = idx_max;
  74
  75         return 0;
  76 }
  77 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
  78
  79 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
  80 {
  81         kfree(ent_enum->bmap);
  82 }
  83 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
  84
  85 /**
  86  *  dev_dbg_obj - Prints in debug mode a change on some object
  87  *
  88  * @event_name: Name of the event to report. Could be __func__
  89  * @gobj:       Pointer to the object
  90  *
  91  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
  92  * won't produce any code.
  93  */
  94 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
  95 {
  96 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
  97         switch (media_type(gobj)) {
  98         case MEDIA_GRAPH_ENTITY:
  99                 dev_dbg(gobj->mdev->dev,
 100                         "%s id %u: entity '%s'\n",
 101                         event_name, media_id(gobj),
 102                         gobj_to_entity(gobj)->name);
 103                 break;
 104         case MEDIA_GRAPH_LINK:
 105         {
 106                 struct media_link *link = gobj_to_link(gobj);
 107
 108                 dev_dbg(gobj->mdev->dev,
 109                         "%s id %u: %s link id %u ==> id %u\n",
 110                         event_name, media_id(gobj),
 111                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 112                                 "data" : "interface",
 113                         media_id(link->gobj0),
 114                         media_id(link->gobj1));
 115                 break;
 116         }
 117         case MEDIA_GRAPH_PAD:
 118         {
 119                 struct media_pad *pad = gobj_to_pad(gobj);
 120
 121                 dev_dbg(gobj->mdev->dev,
 122                         "%s id %u: %s%spad '%s':%d\n",
 123                         event_name, media_id(gobj),
 124                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 125                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 126                         pad->entity->name, pad->index);
 127                 break;
 128         }
 129         case MEDIA_GRAPH_INTF_DEVNODE:
 130         {
 131                 struct media_interface *intf = gobj_to_intf(gobj);
 132                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 133
 134                 dev_dbg(gobj->mdev->dev,
 135                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 136                         event_name, media_id(gobj),
 137                         intf_type(intf),
 138                         devnode->major, devnode->minor);
 139                 break;
 140         }
 141         }
 142 #endif
 143 }
 144
 145 void media_gobj_create(struct media_device *mdev,
 146                            enum media_gobj_type type,
 147                            struct media_gobj *gobj)
 148 {
 149         BUG_ON(!mdev);
 150
 151         gobj->mdev = mdev;
 152
 153         /* Create a per-type unique object ID */
 154         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 155
 156         switch (type) {
 157         case MEDIA_GRAPH_ENTITY:
 158                 list_add_tail(&gobj->list, &mdev->entities);
 159                 break;
 160         case MEDIA_GRAPH_PAD:
 161                 list_add_tail(&gobj->list, &mdev->pads);
 162                 break;
 163         case MEDIA_GRAPH_LINK:
 164                 list_add_tail(&gobj->list, &mdev->links);
 165                 break;
 166         case MEDIA_GRAPH_INTF_DEVNODE:
 167                 list_add_tail(&gobj->list, &mdev->interfaces);
 168                 break;
 169         }
 170
 171         mdev->topology_version++;
 172
 173         dev_dbg_obj(__func__, gobj);
 174 }
 175
 176 void media_gobj_destroy(struct media_gobj *gobj)
 177 {
 178         /* Do nothing if the object is not linked. */
 179         if (gobj->mdev == NULL)
 180                 return;
 181
 182         dev_dbg_obj(__func__, gobj);
 183
 184         gobj->mdev->topology_version++;
 185
 186         /* Remove the object from mdev list */
 187         list_del(&gobj->list);
 188
 189         gobj->mdev = NULL;
 190 }
 191
 192 /*
 193  * TODO: Get rid of this.
 194  */
 195 #define MEDIA_ENTITY_MAX_PADS           512
 196
 197 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 198                            struct media_pad *pads)
 199 {
 200         struct media_device *mdev = entity->graph_obj.mdev;
 201         unsigned int i;
 202
 203         if (num_pads >= MEDIA_ENTITY_MAX_PADS)
 204                 return -E2BIG;
 205
 206         entity->num_pads = num_pads;
 207         entity->pads = pads;
 208
 209         if (mdev)
 210                 mutex_lock(&mdev->graph_mutex);
 211
 212         for (i = 0; i < num_pads; i++) {
 213                 pads[i].entity = entity;
 214                 pads[i].index = i;
 215                 if (mdev)
 216                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 217                                         &entity->pads[i].graph_obj);
 218         }
 219
 220         if (mdev)
 221                 mutex_unlock(&mdev->graph_mutex);
 222
 223         return 0;
 224 }
 225 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 226
 227 /* -----------------------------------------------------------------------------
 228  * Graph traversal
 229  */
 230
 231 static struct media_entity *
 232 media_entity_other(struct media_entity *entity, struct media_link *link)
 233 {
 234         if (link->source->entity == entity)
 235                 return link->sink->entity;
 236         else
 237                 return link->source->entity;
 238 }
 239
 240 /* push an entity to traversal stack */
 241 static void stack_push(struct media_graph *graph,
 242                        struct media_entity *entity)
 243 {
 244         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 245                 WARN_ON(1);
 246                 return;
 247         }
 248         graph->top++;
 249         graph->stack[graph->top].link = entity->links.next;
 250         graph->stack[graph->top].entity = entity;
 251 }
 252
 253 static struct media_entity *stack_pop(struct media_graph *graph)
 254 {
 255         struct media_entity *entity;
 256
 257         entity = graph->stack[graph->top].entity;
 258         graph->top--;
 259
 260         return entity;
 261 }
 262
 263 #define link_top(en)    ((en)->stack[(en)->top].link)
 264 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 265
 266 /**
 267  * media_graph_walk_init - Allocate resources for graph walk
 268  * @graph: Media graph structure that will be used to walk the graph
 269  * @mdev: Media device
 270  *
 271  * Reserve resources for graph walk in media device's current
 272  * state. The memory must be released using
 273  * media_graph_walk_free().
 274  *
 275  * Returns error on failure, zero on success.
 276  */
 277 __must_check int media_graph_walk_init(
 278         struct media_graph *graph, struct media_device *mdev)
 279 {
 280         return media_entity_enum_init(&graph->ent_enum, mdev);
 281 }
 282 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 283
 284 /**
 285  * media_graph_walk_cleanup - Release resources related to graph walking
 286  * @graph: Media graph structure that was used to walk the graph
 287  */
 288 void media_graph_walk_cleanup(struct media_graph *graph)
 289 {
 290         media_entity_enum_cleanup(&graph->ent_enum);
 291 }
 292 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 293
 294 void media_graph_walk_start(struct media_graph *graph,
 295                             struct media_entity *entity)
 296 {
 297         media_entity_enum_zero(&graph->ent_enum);
 298         media_entity_enum_set(&graph->ent_enum, entity);
 299
 300         graph->top = 0;
 301         graph->stack[graph->top].entity = NULL;
 302         stack_push(graph, entity);
 303         dev_dbg(entity->graph_obj.mdev->dev,
 304                 "begin graph walk at '%s'\n", entity->name);
 305 }
 306 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 307
 308 static void media_graph_walk_iter(struct media_graph *graph)
 309 {
 310         struct media_entity *entity = stack_top(graph);
 311         struct media_link *link;
 312         struct media_entity *next;
 313
 314         link = list_entry(link_top(graph), typeof(*link), list);
 315
 316         /* The link is not enabled so we do not follow. */
 317         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 318                 link_top(graph) = link_top(graph)->next;
 319                 dev_dbg(entity->graph_obj.mdev->dev,
 320                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 321                         link->source->entity->name, link->source->index,
 322                         link->sink->entity->name, link->sink->index);
 323                 return;
 324         }
 325
 326         /* Get the entity in the other end of the link . */
 327         next = media_entity_other(entity, link);
 328
 329         /* Has the entity already been visited? */
 330         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 331                 link_top(graph) = link_top(graph)->next;
 332                 dev_dbg(entity->graph_obj.mdev->dev,
 333                         "walk: skipping entity '%s' (already seen)\n",
 334                         next->name);
 335                 return;
 336         }
 337
 338         /* Push the new entity to stack and start over. */
 339         link_top(graph) = link_top(graph)->next;
 340         stack_push(graph, next);
 341         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 342                 next->name);
 343 }
 344
 345 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 346 {
 347         struct media_entity *entity;
 348
 349         if (stack_top(graph) == NULL)
 350                 return NULL;
 351
 352         /*
 353          * Depth first search. Push entity to stack and continue from
 354          * top of the stack until no more entities on the level can be
 355          * found.
 356          */
 357         while (link_top(graph) != &stack_top(graph)->links)
 358                 media_graph_walk_iter(graph);
 359
 360         entity = stack_pop(graph);
 361         dev_dbg(entity->graph_obj.mdev->dev,
 362                 "walk: returning entity '%s'\n", entity->name);
 363
 364         return entity;
 365 }
 366 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 367
 368 int media_entity_get_fwnode_pad(struct media_entity *entity,
 369                                 struct fwnode_handle *fwnode,
 370                                 unsigned long direction_flags)
 371 {
 372         struct fwnode_endpoint endpoint;
 373         unsigned int i;
 374         int ret;
 375
 376         if (!entity->ops || !entity->ops->get_fwnode_pad) {
 377                 for (i = 0; i < entity->num_pads; i++) {
 378                         if (entity->pads[i].flags & direction_flags)
 379                                 return i;
 380                 }
 381
 382                 return -ENXIO;
 383         }
 384
 385         ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
 386         if (ret)
 387                 return ret;
 388
 389         ret = entity->ops->get_fwnode_pad(&endpoint);
 390         if (ret < 0)
 391                 return ret;
 392
 393         if (ret >= entity->num_pads)
 394                 return -ENXIO;
 395
 396         if (!(entity->pads[ret].flags & direction_flags))
 397                 return -ENXIO;
 398
 399         return ret;
 400 }
 401 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
 402
 403 /* -----------------------------------------------------------------------------
 404  * Pipeline management
 405  */
 406
 407 __must_check int __media_pipeline_start(struct media_entity *entity,
 408                                         struct media_pipeline *pipe)
 409 {
 410         struct media_device *mdev = entity->graph_obj.mdev;
 411         struct media_graph *graph = &pipe->graph;
 412         struct media_entity *entity_err = entity;
 413         struct media_link *link;
 414         int ret;
 415
 416         if (!pipe->streaming_count++) {
 417                 ret = media_graph_walk_init(&pipe->graph, mdev);
 418                 if (ret)
 419                         goto error_graph_walk_start;
 420         }
 421
 422         media_graph_walk_start(&pipe->graph, entity);
 423
 424         while ((entity = media_graph_walk_next(graph))) {
 425                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 426                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 427
 428                 entity->stream_count++;
 429
 430                 if (entity->pipe && entity->pipe != pipe) {
 431                         pr_err("Pipe active for %s. Can't start for %s\n",
 432                                 entity->name,
 433                                 entity_err->name);
 434                         ret = -EBUSY;
 435                         goto error;
 436                 }
 437
 438                 entity->pipe = pipe;
 439
 440                 /* Already streaming --- no need to check. */
 441                 if (entity->stream_count > 1)
 442                         continue;
 443
 444                 if (!entity->ops || !entity->ops->link_validate)
 445                         continue;
 446
 447                 bitmap_zero(active, entity->num_pads);
 448                 bitmap_fill(has_no_links, entity->num_pads);
 449
 450                 list_for_each_entry(link, &entity->links, list) {
 451                         struct media_pad *pad = link->sink->entity == entity
 452                                                 ? link->sink : link->source;
 453
 454                         /* Mark that a pad is connected by a link. */
 455                         bitmap_clear(has_no_links, pad->index, 1);
 456
 457                         /*
 458                          * Pads that either do not need to connect or
 459                          * are connected through an enabled link are
 460                          * fine.
 461                          */
 462                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 463                             link->flags & MEDIA_LNK_FL_ENABLED)
 464                                 bitmap_set(active, pad->index, 1);
 465
 466                         /*
 467                          * Link validation will only take place for
 468                          * sink ends of the link that are enabled.
 469                          */
 470                         if (link->sink != pad ||
 471                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 472                                 continue;
 473
 474                         ret = entity->ops->link_validate(link);
 475                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 476                                 dev_dbg(entity->graph_obj.mdev->dev,
 477                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 478                                         link->source->entity->name,
 479                                         link->source->index,
 480                                         entity->name, link->sink->index, ret);
 481                                 goto error;
 482                         }
 483                 }
 484
 485                 /* Either no links or validated links are fine. */
 486                 bitmap_or(active, active, has_no_links, entity->num_pads);
 487
 488                 if (!bitmap_full(active, entity->num_pads)) {
 489                         ret = -ENOLINK;
 490                         dev_dbg(entity->graph_obj.mdev->dev,
 491                                 "'%s':%u must be connected by an enabled link\n",
 492                                 entity->name,
 493                                 (unsigned)find_first_zero_bit(
 494                                         active, entity->num_pads));
 495                         goto error;
 496                 }
 497         }
 498
 499         return 0;
 500
 501 error:
 502         /*
 503          * Link validation on graph failed. We revert what we did and
 504          * return the error.
 505          */
 506         media_graph_walk_start(graph, entity_err);
 507
 508         while ((entity_err = media_graph_walk_next(graph))) {
 509                 /* Sanity check for negative stream_count */
 510                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 511                         entity_err->stream_count--;
 512                         if (entity_err->stream_count == 0)
 513                                 entity_err->pipe = NULL;
 514                 }
 515
 516                 /*
 517                  * We haven't increased stream_count further than this
 518                  * so we quit here.
 519                  */
 520                 if (entity_err == entity)
 521                         break;
 522         }
 523
 524 error_graph_walk_start:
 525         if (!--pipe->streaming_count)
 526                 media_graph_walk_cleanup(graph);
 527
 528         return ret;
 529 }
 530 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 531
 532 __must_check int media_pipeline_start(struct media_entity *entity,
 533                                       struct media_pipeline *pipe)
 534 {
 535         struct media_device *mdev = entity->graph_obj.mdev;
 536         int ret;
 537
 538         mutex_lock(&mdev->graph_mutex);
 539         ret = __media_pipeline_start(entity, pipe);
 540         mutex_unlock(&mdev->graph_mutex);
 541         return ret;
 542 }
 543 EXPORT_SYMBOL_GPL(media_pipeline_start);
 544
 545 void __media_pipeline_stop(struct media_entity *entity)
 546 {
 547         struct media_graph *graph = &entity->pipe->graph;
 548         struct media_pipeline *pipe = entity->pipe;
 549
 550         /*
 551          * If the following check fails, the driver has performed an
 552          * unbalanced call to media_pipeline_stop()
 553          */
 554         if (WARN_ON(!pipe))
 555                 return;
 556
 557         media_graph_walk_start(graph, entity);
 558
 559         while ((entity = media_graph_walk_next(graph))) {
 560                 /* Sanity check for negative stream_count */
 561                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 562                         entity->stream_count--;
 563                         if (entity->stream_count == 0)
 564                                 entity->pipe = NULL;
 565                 }
 566         }
 567
 568         if (!--pipe->streaming_count)
 569                 media_graph_walk_cleanup(graph);
 570
 571 }
 572 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 573
 574 void media_pipeline_stop(struct media_entity *entity)
 575 {
 576         struct media_device *mdev = entity->graph_obj.mdev;
 577
 578         mutex_lock(&mdev->graph_mutex);
 579         __media_pipeline_stop(entity);
 580         mutex_unlock(&mdev->graph_mutex);
 581 }
 582 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 583
 584 /* -----------------------------------------------------------------------------
 585  * Links management
 586  */
 587
 588 static struct media_link *media_add_link(struct list_head *head)
 589 {
 590         struct media_link *link;
 591
 592         link = kzalloc(sizeof(*link), GFP_KERNEL);
 593         if (link == NULL)
 594                 return NULL;
 595
 596         list_add_tail(&link->list, head);
 597
 598         return link;
 599 }
 600
 601 static void __media_entity_remove_link(struct media_entity *entity,
 602                                        struct media_link *link)
 603 {
 604         struct media_link *rlink, *tmp;
 605         struct media_entity *remote;
 606
 607         if (link->source->entity == entity)
 608                 remote = link->sink->entity;
 609         else
 610                 remote = link->source->entity;
 611
 612         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 613                 if (rlink != link->reverse)
 614                         continue;
 615
 616                 if (link->source->entity == entity)
 617                         remote->num_backlinks--;
 618
 619                 /* Remove the remote link */
 620                 list_del(&rlink->list);
 621                 media_gobj_destroy(&rlink->graph_obj);
 622                 kfree(rlink);
 623
 624                 if (--remote->num_links == 0)
 625                         break;
 626         }
 627         list_del(&link->list);
 628         media_gobj_destroy(&link->graph_obj);
 629         kfree(link);
 630 }
 631
 632 int media_get_pad_index(struct media_entity *entity, bool is_sink,
 633                         enum media_pad_signal_type sig_type)
 634 {
 635         int i;
 636         bool pad_is_sink;
 637
 638         if (!entity)
 639                 return -EINVAL;
 640
 641         for (i = 0; i < entity->num_pads; i++) {
 642                 if (entity->pads[i].flags & MEDIA_PAD_FL_SINK)
 643                         pad_is_sink = true;
 644                 else if (entity->pads[i].flags & MEDIA_PAD_FL_SOURCE)
 645                         pad_is_sink = false;
 646                 else
 647                         continue;       /* This is an error! */
 648
 649                 if (pad_is_sink != is_sink)
 650                         continue;
 651                 if (entity->pads[i].sig_type == sig_type)
 652                         return i;
 653         }
 654         return -EINVAL;
 655 }
 656 EXPORT_SYMBOL_GPL(media_get_pad_index);
 657
 658 int
 659 media_create_pad_link(struct media_entity *source, u16 source_pad,
 660                          struct media_entity *sink, u16 sink_pad, u32 flags)
 661 {
 662         struct media_link *link;
 663         struct media_link *backlink;
 664
 665         if (WARN_ON(!source || !sink) ||
 666             WARN_ON(source_pad >= source->num_pads) ||
 667             WARN_ON(sink_pad >= sink->num_pads))
 668                 return -EINVAL;
 669         if (WARN_ON(!(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE)))
 670                 return -EINVAL;
 671         if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
 672                 return -EINVAL;
 673
 674         link = media_add_link(&source->links);
 675         if (link == NULL)
 676                 return -ENOMEM;
 677
 678         link->source = &source->pads[source_pad];
 679         link->sink = &sink->pads[sink_pad];
 680         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 681
 682         /* Initialize graph object embedded at the new link */
 683         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 684                         &link->graph_obj);
 685
 686         /* Create the backlink. Backlinks are used to help graph traversal and
 687          * are not reported to userspace.
 688          */
 689         backlink = media_add_link(&sink->links);
 690         if (backlink == NULL) {
 691                 __media_entity_remove_link(source, link);
 692                 return -ENOMEM;
 693         }
 694
 695         backlink->source = &source->pads[source_pad];
 696         backlink->sink = &sink->pads[sink_pad];
 697         backlink->flags = flags;
 698         backlink->is_backlink = true;
 699
 700         /* Initialize graph object embedded at the new link */
 701         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 702                         &backlink->graph_obj);
 703
 704         link->reverse = backlink;
 705         backlink->reverse = link;
 706
 707         sink->num_backlinks++;
 708         sink->num_links++;
 709         source->num_links++;
 710
 711         return 0;
 712 }
 713 EXPORT_SYMBOL_GPL(media_create_pad_link);
 714
 715 int media_create_pad_links(const struct media_device *mdev,
 716                            const u32 source_function,
 717                            struct media_entity *source,
 718                            const u16 source_pad,
 719                            const u32 sink_function,
 720                            struct media_entity *sink,
 721                            const u16 sink_pad,
 722                            u32 flags,
 723                            const bool allow_both_undefined)
 724 {
 725         struct media_entity *entity;
 726         unsigned function;
 727         int ret;
 728
 729         /* Trivial case: 1:1 relation */
 730         if (source && sink)
 731                 return media_create_pad_link(source, source_pad,
 732                                              sink, sink_pad, flags);
 733
 734         /* Worse case scenario: n:n relation */
 735         if (!source && !sink) {
 736                 if (!allow_both_undefined)
 737                         return 0;
 738                 media_device_for_each_entity(source, mdev) {
 739                         if (source->function != source_function)
 740                                 continue;
 741                         media_device_for_each_entity(sink, mdev) {
 742                                 if (sink->function != sink_function)
 743                                         continue;
 744                                 ret = media_create_pad_link(source, source_pad,
 745                                                             sink, sink_pad,
 746                                                             flags);
 747                                 if (ret)
 748                                         return ret;
 749                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 750                                            MEDIA_LNK_FL_IMMUTABLE);
 751                         }
 752                 }
 753                 return 0;
 754         }
 755
 756         /* Handle 1:n and n:1 cases */
 757         if (source)
 758                 function = sink_function;
 759         else
 760                 function = source_function;
 761
 762         media_device_for_each_entity(entity, mdev) {
 763                 if (entity->function != function)
 764                         continue;
 765
 766                 if (source)
 767                         ret = media_create_pad_link(source, source_pad,
 768                                                     entity, sink_pad, flags);
 769                 else
 770                         ret = media_create_pad_link(entity, source_pad,
 771                                                     sink, sink_pad, flags);
 772                 if (ret)
 773                         return ret;
 774                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 775         }
 776         return 0;
 777 }
 778 EXPORT_SYMBOL_GPL(media_create_pad_links);
 779
 780 void __media_entity_remove_links(struct media_entity *entity)
 781 {
 782         struct media_link *link, *tmp;
 783
 784         list_for_each_entry_safe(link, tmp, &entity->links, list)
 785                 __media_entity_remove_link(entity, link);
 786
 787         entity->num_links = 0;
 788         entity->num_backlinks = 0;
 789 }
 790 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 791
 792 void media_entity_remove_links(struct media_entity *entity)
 793 {
 794         struct media_device *mdev = entity->graph_obj.mdev;
 795
 796         /* Do nothing if the entity is not registered. */
 797         if (mdev == NULL)
 798                 return;
 799
 800         mutex_lock(&mdev->graph_mutex);
 801         __media_entity_remove_links(entity);
 802         mutex_unlock(&mdev->graph_mutex);
 803 }
 804 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 805
 806 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 807 {
 808         int ret;
 809
 810         /* Notify both entities. */
 811         ret = media_entity_call(link->source->entity, link_setup,
 812                                 link->source, link->sink, flags);
 813         if (ret < 0 && ret != -ENOIOCTLCMD)
 814                 return ret;
 815
 816         ret = media_entity_call(link->sink->entity, link_setup,
 817                                 link->sink, link->source, flags);
 818         if (ret < 0 && ret != -ENOIOCTLCMD) {
 819                 media_entity_call(link->source->entity, link_setup,
 820                                   link->source, link->sink, link->flags);
 821                 return ret;
 822         }
 823
 824         link->flags = flags;
 825         link->reverse->flags = link->flags;
 826
 827         return 0;
 828 }
 829
 830 int __media_entity_setup_link(struct media_link *link, u32 flags)
 831 {
 832         const u32 mask = MEDIA_LNK_FL_ENABLED;
 833         struct media_device *mdev;
 834         struct media_entity *source, *sink;
 835         int ret = -EBUSY;
 836
 837         if (link == NULL)
 838                 return -EINVAL;
 839
 840         /* The non-modifiable link flags must not be modified. */
 841         if ((link->flags & ~mask) != (flags & ~mask))
 842                 return -EINVAL;
 843
 844         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 845                 return link->flags == flags ? 0 : -EINVAL;
 846
 847         if (link->flags == flags)
 848                 return 0;
 849
 850         source = link->source->entity;
 851         sink = link->sink->entity;
 852
 853         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 854             (source->stream_count || sink->stream_count))
 855                 return -EBUSY;
 856
 857         mdev = source->graph_obj.mdev;
 858
 859         if (mdev->ops && mdev->ops->link_notify) {
 860                 ret = mdev->ops->link_notify(link, flags,
 861                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 862                 if (ret < 0)
 863                         return ret;
 864         }
 865
 866         ret = __media_entity_setup_link_notify(link, flags);
 867
 868         if (mdev->ops && mdev->ops->link_notify)
 869                 mdev->ops->link_notify(link, flags,
 870                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 871
 872         return ret;
 873 }
 874 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 875
 876 int media_entity_setup_link(struct media_link *link, u32 flags)
 877 {
 878         int ret;
 879
 880         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 881         ret = __media_entity_setup_link(link, flags);
 882         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 883
 884         return ret;
 885 }
 886 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 887
 888 struct media_link *
 889 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 890 {
 891         struct media_link *link;
 892
 893         list_for_each_entry(link, &source->entity->links, list) {
 894                 if (link->source->entity == source->entity &&
 895                     link->source->index == source->index &&
 896                     link->sink->entity == sink->entity &&
 897                     link->sink->index == sink->index)
 898                         return link;
 899         }
 900
 901         return NULL;
 902 }
 903 EXPORT_SYMBOL_GPL(media_entity_find_link);
 904
 905 struct media_pad *media_entity_remote_pad(const struct media_pad *pad)
 906 {
 907         struct media_link *link;
 908
 909         list_for_each_entry(link, &pad->entity->links, list) {
 910                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 911                         continue;
 912
 913                 if (link->source == pad)
 914                         return link->sink;
 915
 916                 if (link->sink == pad)
 917                         return link->source;
 918         }
 919
 920         return NULL;
 921
 922 }
 923 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 924
 925 static void media_interface_init(struct media_device *mdev,
 926                                  struct media_interface *intf,
 927                                  u32 gobj_type,
 928                                  u32 intf_type, u32 flags)
 929 {
 930         intf->type = intf_type;
 931         intf->flags = flags;
 932         INIT_LIST_HEAD(&intf->links);
 933
 934         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 935 }
 936
 937 /* Functions related to the media interface via device nodes */
 938
 939 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 940                                                 u32 type, u32 flags,
 941                                                 u32 major, u32 minor)
 942 {
 943         struct media_intf_devnode *devnode;
 944
 945         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 946         if (!devnode)
 947                 return NULL;
 948
 949         devnode->major = major;
 950         devnode->minor = minor;
 951
 952         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 953                              type, flags);
 954
 955         return devnode;
 956 }
 957 EXPORT_SYMBOL_GPL(media_devnode_create);
 958
 959 void media_devnode_remove(struct media_intf_devnode *devnode)
 960 {
 961         media_remove_intf_links(&devnode->intf);
 962         media_gobj_destroy(&devnode->intf.graph_obj);
 963         kfree(devnode);
 964 }
 965 EXPORT_SYMBOL_GPL(media_devnode_remove);
 966
 967 struct media_link *media_create_intf_link(struct media_entity *entity,
 968                                             struct media_interface *intf,
 969                                             u32 flags)
 970 {
 971         struct media_link *link;
 972
 973         link = media_add_link(&intf->links);
 974         if (link == NULL)
 975                 return NULL;
 976
 977         link->intf = intf;
 978         link->entity = entity;
 979         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 980
 981         /* Initialize graph object embedded at the new link */
 982         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 983                         &link->graph_obj);
 984
 985         return link;
 986 }
 987 EXPORT_SYMBOL_GPL(media_create_intf_link);
 988
 989 void __media_remove_intf_link(struct media_link *link)
 990 {
 991         list_del(&link->list);
 992         media_gobj_destroy(&link->graph_obj);
 993         kfree(link);
 994 }
 995 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 996
 997 void media_remove_intf_link(struct media_link *link)
 998 {
 999         struct media_device *mdev = link->graph_obj.mdev;
1000
1001         /* Do nothing if the intf is not registered. */
1002         if (mdev == NULL)
1003                 return;
1004
1005         mutex_lock(&mdev->graph_mutex);
1006         __media_remove_intf_link(link);
1007         mutex_unlock(&mdev->graph_mutex);
1008 }
1009 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1010
1011 void __media_remove_intf_links(struct media_interface *intf)
1012 {
1013         struct media_link *link, *tmp;
1014
1015         list_for_each_entry_safe(link, tmp, &intf->links, list)
1016                 __media_remove_intf_link(link);
1017
1018 }
1019 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1020
1021 void media_remove_intf_links(struct media_interface *intf)
1022 {
1023         struct media_device *mdev = intf->graph_obj.mdev;
1024
1025         /* Do nothing if the intf is not registered. */
1026         if (mdev == NULL)
1027                 return;
1028
1029         mutex_lock(&mdev->graph_mutex);
1030         __media_remove_intf_links(intf);
1031         mutex_unlock(&mdev->graph_mutex);
1032 }
1033 EXPORT_SYMBOL_GPL(media_remove_intf_links);