drivers/media/media-entity.c

   1 /*
   2  * Media entity
   3  *
   4  * Copyright (C) 2010 Nokia Corporation
   5  *
   6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   7  *           Sakari Ailus <sakari.ailus@iki.fi>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/bitmap.h>
  20 #include <linux/module.h>
  21 #include <linux/property.h>
  22 #include <linux/slab.h>
  23 #include <media/media-entity.h>
  24 #include <media/media-device.h>
  25
  26 static inline const char *gobj_type(enum media_gobj_type type)
  27 {
  28         switch (type) {
  29         case MEDIA_GRAPH_ENTITY:
  30                 return "entity";
  31         case MEDIA_GRAPH_PAD:
  32                 return "pad";
  33         case MEDIA_GRAPH_LINK:
  34                 return "link";
  35         case MEDIA_GRAPH_INTF_DEVNODE:
  36                 return "intf-devnode";
  37         default:
  38                 return "unknown";
  39         }
  40 }
  41
  42 static inline const char *intf_type(struct media_interface *intf)
  43 {
  44         switch (intf->type) {
  45         case MEDIA_INTF_T_DVB_FE:
  46                 return "dvb-frontend";
  47         case MEDIA_INTF_T_DVB_DEMUX:
  48                 return "dvb-demux";
  49         case MEDIA_INTF_T_DVB_DVR:
  50                 return "dvb-dvr";
  51         case MEDIA_INTF_T_DVB_CA:
  52                 return  "dvb-ca";
  53         case MEDIA_INTF_T_DVB_NET:
  54                 return "dvb-net";
  55         case MEDIA_INTF_T_V4L_VIDEO:
  56                 return "v4l-video";
  57         case MEDIA_INTF_T_V4L_VBI:
  58                 return "v4l-vbi";
  59         case MEDIA_INTF_T_V4L_RADIO:
  60                 return "v4l-radio";
  61         case MEDIA_INTF_T_V4L_SUBDEV:
  62                 return "v4l-subdev";
  63         case MEDIA_INTF_T_V4L_SWRADIO:
  64                 return "v4l-swradio";
  65         case MEDIA_INTF_T_V4L_TOUCH:
  66                 return "v4l-touch";
  67         case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
  68                 return "alsa-pcm-capture";
  69         case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
  70                 return "alsa-pcm-playback";
  71         case MEDIA_INTF_T_ALSA_CONTROL:
  72                 return "alsa-control";
  73         case MEDIA_INTF_T_ALSA_COMPRESS:
  74                 return "alsa-compress";
  75         case MEDIA_INTF_T_ALSA_RAWMIDI:
  76                 return "alsa-rawmidi";
  77         case MEDIA_INTF_T_ALSA_HWDEP:
  78                 return "alsa-hwdep";
  79         case MEDIA_INTF_T_ALSA_SEQUENCER:
  80                 return "alsa-sequencer";
  81         case MEDIA_INTF_T_ALSA_TIMER:
  82                 return "alsa-timer";
  83         default:
  84                 return "unknown-intf";
  85         }
  86 };
  87
  88 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  89                                           int idx_max)
  90 {
  91         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  92         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  93                                  GFP_KERNEL);
  94         if (!ent_enum->bmap)
  95                 return -ENOMEM;
  96
  97         bitmap_zero(ent_enum->bmap, idx_max);
  98         ent_enum->idx_max = idx_max;
  99
 100         return 0;
 101 }
 102 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
 103
 104 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
 105 {
 106         kfree(ent_enum->bmap);
 107 }
 108 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
 109
 110 /**
 111  *  dev_dbg_obj - Prints in debug mode a change on some object
 112  *
 113  * @event_name: Name of the event to report. Could be __func__
 114  * @gobj:       Pointer to the object
 115  *
 116  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 117  * won't produce any code.
 118  */
 119 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 120 {
 121 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 122         switch (media_type(gobj)) {
 123         case MEDIA_GRAPH_ENTITY:
 124                 dev_dbg(gobj->mdev->dev,
 125                         "%s id %u: entity '%s'\n",
 126                         event_name, media_id(gobj),
 127                         gobj_to_entity(gobj)->name);
 128                 break;
 129         case MEDIA_GRAPH_LINK:
 130         {
 131                 struct media_link *link = gobj_to_link(gobj);
 132
 133                 dev_dbg(gobj->mdev->dev,
 134                         "%s id %u: %s link id %u ==> id %u\n",
 135                         event_name, media_id(gobj),
 136                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 137                                 "data" : "interface",
 138                         media_id(link->gobj0),
 139                         media_id(link->gobj1));
 140                 break;
 141         }
 142         case MEDIA_GRAPH_PAD:
 143         {
 144                 struct media_pad *pad = gobj_to_pad(gobj);
 145
 146                 dev_dbg(gobj->mdev->dev,
 147                         "%s id %u: %s%spad '%s':%d\n",
 148                         event_name, media_id(gobj),
 149                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 150                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 151                         pad->entity->name, pad->index);
 152                 break;
 153         }
 154         case MEDIA_GRAPH_INTF_DEVNODE:
 155         {
 156                 struct media_interface *intf = gobj_to_intf(gobj);
 157                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 158
 159                 dev_dbg(gobj->mdev->dev,
 160                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 161                         event_name, media_id(gobj),
 162                         intf_type(intf),
 163                         devnode->major, devnode->minor);
 164                 break;
 165         }
 166         }
 167 #endif
 168 }
 169
 170 void media_gobj_create(struct media_device *mdev,
 171                            enum media_gobj_type type,
 172                            struct media_gobj *gobj)
 173 {
 174         BUG_ON(!mdev);
 175
 176         gobj->mdev = mdev;
 177
 178         /* Create a per-type unique object ID */
 179         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 180
 181         switch (type) {
 182         case MEDIA_GRAPH_ENTITY:
 183                 list_add_tail(&gobj->list, &mdev->entities);
 184                 break;
 185         case MEDIA_GRAPH_PAD:
 186                 list_add_tail(&gobj->list, &mdev->pads);
 187                 break;
 188         case MEDIA_GRAPH_LINK:
 189                 list_add_tail(&gobj->list, &mdev->links);
 190                 break;
 191         case MEDIA_GRAPH_INTF_DEVNODE:
 192                 list_add_tail(&gobj->list, &mdev->interfaces);
 193                 break;
 194         }
 195
 196         mdev->topology_version++;
 197
 198         dev_dbg_obj(__func__, gobj);
 199 }
 200
 201 void media_gobj_destroy(struct media_gobj *gobj)
 202 {
 203         /* Do nothing if the object is not linked. */
 204         if (gobj->mdev == NULL)
 205                 return;
 206
 207         dev_dbg_obj(__func__, gobj);
 208
 209         gobj->mdev->topology_version++;
 210
 211         /* Remove the object from mdev list */
 212         list_del(&gobj->list);
 213
 214         gobj->mdev = NULL;
 215 }
 216
 217 /*
 218  * TODO: Get rid of this.
 219  */
 220 #define MEDIA_ENTITY_MAX_PADS           512
 221
 222 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 223                            struct media_pad *pads)
 224 {
 225         struct media_device *mdev = entity->graph_obj.mdev;
 226         unsigned int i;
 227
 228         if (num_pads >= MEDIA_ENTITY_MAX_PADS)
 229                 return -E2BIG;
 230
 231         entity->num_pads = num_pads;
 232         entity->pads = pads;
 233
 234         if (mdev)
 235                 mutex_lock(&mdev->graph_mutex);
 236
 237         for (i = 0; i < num_pads; i++) {
 238                 pads[i].entity = entity;
 239                 pads[i].index = i;
 240                 if (mdev)
 241                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 242                                         &entity->pads[i].graph_obj);
 243         }
 244
 245         if (mdev)
 246                 mutex_unlock(&mdev->graph_mutex);
 247
 248         return 0;
 249 }
 250 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 251
 252 /* -----------------------------------------------------------------------------
 253  * Graph traversal
 254  */
 255
 256 static struct media_entity *
 257 media_entity_other(struct media_entity *entity, struct media_link *link)
 258 {
 259         if (link->source->entity == entity)
 260                 return link->sink->entity;
 261         else
 262                 return link->source->entity;
 263 }
 264
 265 /* push an entity to traversal stack */
 266 static void stack_push(struct media_graph *graph,
 267                        struct media_entity *entity)
 268 {
 269         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 270                 WARN_ON(1);
 271                 return;
 272         }
 273         graph->top++;
 274         graph->stack[graph->top].link = entity->links.next;
 275         graph->stack[graph->top].entity = entity;
 276 }
 277
 278 static struct media_entity *stack_pop(struct media_graph *graph)
 279 {
 280         struct media_entity *entity;
 281
 282         entity = graph->stack[graph->top].entity;
 283         graph->top--;
 284
 285         return entity;
 286 }
 287
 288 #define link_top(en)    ((en)->stack[(en)->top].link)
 289 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 290
 291 /**
 292  * media_graph_walk_init - Allocate resources for graph walk
 293  * @graph: Media graph structure that will be used to walk the graph
 294  * @mdev: Media device
 295  *
 296  * Reserve resources for graph walk in media device's current
 297  * state. The memory must be released using
 298  * media_graph_walk_free().
 299  *
 300  * Returns error on failure, zero on success.
 301  */
 302 __must_check int media_graph_walk_init(
 303         struct media_graph *graph, struct media_device *mdev)
 304 {
 305         return media_entity_enum_init(&graph->ent_enum, mdev);
 306 }
 307 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 308
 309 /**
 310  * media_graph_walk_cleanup - Release resources related to graph walking
 311  * @graph: Media graph structure that was used to walk the graph
 312  */
 313 void media_graph_walk_cleanup(struct media_graph *graph)
 314 {
 315         media_entity_enum_cleanup(&graph->ent_enum);
 316 }
 317 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 318
 319 void media_graph_walk_start(struct media_graph *graph,
 320                             struct media_entity *entity)
 321 {
 322         media_entity_enum_zero(&graph->ent_enum);
 323         media_entity_enum_set(&graph->ent_enum, entity);
 324
 325         graph->top = 0;
 326         graph->stack[graph->top].entity = NULL;
 327         stack_push(graph, entity);
 328         dev_dbg(entity->graph_obj.mdev->dev,
 329                 "begin graph walk at '%s'\n", entity->name);
 330 }
 331 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 332
 333 static void media_graph_walk_iter(struct media_graph *graph)
 334 {
 335         struct media_entity *entity = stack_top(graph);
 336         struct media_link *link;
 337         struct media_entity *next;
 338
 339         link = list_entry(link_top(graph), typeof(*link), list);
 340
 341         /* The link is not enabled so we do not follow. */
 342         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 343                 link_top(graph) = link_top(graph)->next;
 344                 dev_dbg(entity->graph_obj.mdev->dev,
 345                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 346                         link->source->entity->name, link->source->index,
 347                         link->sink->entity->name, link->sink->index);
 348                 return;
 349         }
 350
 351         /* Get the entity in the other end of the link . */
 352         next = media_entity_other(entity, link);
 353
 354         /* Has the entity already been visited? */
 355         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 356                 link_top(graph) = link_top(graph)->next;
 357                 dev_dbg(entity->graph_obj.mdev->dev,
 358                         "walk: skipping entity '%s' (already seen)\n",
 359                         next->name);
 360                 return;
 361         }
 362
 363         /* Push the new entity to stack and start over. */
 364         link_top(graph) = link_top(graph)->next;
 365         stack_push(graph, next);
 366         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 367                 next->name);
 368 }
 369
 370 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 371 {
 372         struct media_entity *entity;
 373
 374         if (stack_top(graph) == NULL)
 375                 return NULL;
 376
 377         /*
 378          * Depth first search. Push entity to stack and continue from
 379          * top of the stack until no more entities on the level can be
 380          * found.
 381          */
 382         while (link_top(graph) != &stack_top(graph)->links)
 383                 media_graph_walk_iter(graph);
 384
 385         entity = stack_pop(graph);
 386         dev_dbg(entity->graph_obj.mdev->dev,
 387                 "walk: returning entity '%s'\n", entity->name);
 388
 389         return entity;
 390 }
 391 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 392
 393 int media_entity_get_fwnode_pad(struct media_entity *entity,
 394                                 struct fwnode_handle *fwnode,
 395                                 unsigned long direction_flags)
 396 {
 397         struct fwnode_endpoint endpoint;
 398         unsigned int i;
 399         int ret;
 400
 401         if (!entity->ops || !entity->ops->get_fwnode_pad) {
 402                 for (i = 0; i < entity->num_pads; i++) {
 403                         if (entity->pads[i].flags & direction_flags)
 404                                 return i;
 405                 }
 406
 407                 return -ENXIO;
 408         }
 409
 410         ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
 411         if (ret)
 412                 return ret;
 413
 414         ret = entity->ops->get_fwnode_pad(&endpoint);
 415         if (ret < 0)
 416                 return ret;
 417
 418         if (ret >= entity->num_pads)
 419                 return -ENXIO;
 420
 421         if (!(entity->pads[ret].flags & direction_flags))
 422                 return -ENXIO;
 423
 424         return ret;
 425 }
 426 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
 427
 428 /* -----------------------------------------------------------------------------
 429  * Pipeline management
 430  */
 431
 432 __must_check int __media_pipeline_start(struct media_entity *entity,
 433                                         struct media_pipeline *pipe)
 434 {
 435         struct media_device *mdev = entity->graph_obj.mdev;
 436         struct media_graph *graph = &pipe->graph;
 437         struct media_entity *entity_err = entity;
 438         struct media_link *link;
 439         int ret;
 440
 441         if (!pipe->streaming_count++) {
 442                 ret = media_graph_walk_init(&pipe->graph, mdev);
 443                 if (ret)
 444                         goto error_graph_walk_start;
 445         }
 446
 447         media_graph_walk_start(&pipe->graph, entity);
 448
 449         while ((entity = media_graph_walk_next(graph))) {
 450                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 451                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 452
 453                 entity->stream_count++;
 454
 455                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 456                         ret = -EBUSY;
 457                         goto error;
 458                 }
 459
 460                 entity->pipe = pipe;
 461
 462                 /* Already streaming --- no need to check. */
 463                 if (entity->stream_count > 1)
 464                         continue;
 465
 466                 if (!entity->ops || !entity->ops->link_validate)
 467                         continue;
 468
 469                 bitmap_zero(active, entity->num_pads);
 470                 bitmap_fill(has_no_links, entity->num_pads);
 471
 472                 list_for_each_entry(link, &entity->links, list) {
 473                         struct media_pad *pad = link->sink->entity == entity
 474                                                 ? link->sink : link->source;
 475
 476                         /* Mark that a pad is connected by a link. */
 477                         bitmap_clear(has_no_links, pad->index, 1);
 478
 479                         /*
 480                          * Pads that either do not need to connect or
 481                          * are connected through an enabled link are
 482                          * fine.
 483                          */
 484                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 485                             link->flags & MEDIA_LNK_FL_ENABLED)
 486                                 bitmap_set(active, pad->index, 1);
 487
 488                         /*
 489                          * Link validation will only take place for
 490                          * sink ends of the link that are enabled.
 491                          */
 492                         if (link->sink != pad ||
 493                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 494                                 continue;
 495
 496                         ret = entity->ops->link_validate(link);
 497                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 498                                 dev_dbg(entity->graph_obj.mdev->dev,
 499                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 500                                         link->source->entity->name,
 501                                         link->source->index,
 502                                         entity->name, link->sink->index, ret);
 503                                 goto error;
 504                         }
 505                 }
 506
 507                 /* Either no links or validated links are fine. */
 508                 bitmap_or(active, active, has_no_links, entity->num_pads);
 509
 510                 if (!bitmap_full(active, entity->num_pads)) {
 511                         ret = -ENOLINK;
 512                         dev_dbg(entity->graph_obj.mdev->dev,
 513                                 "'%s':%u must be connected by an enabled link\n",
 514                                 entity->name,
 515                                 (unsigned)find_first_zero_bit(
 516                                         active, entity->num_pads));
 517                         goto error;
 518                 }
 519         }
 520
 521         return 0;
 522
 523 error:
 524         /*
 525          * Link validation on graph failed. We revert what we did and
 526          * return the error.
 527          */
 528         media_graph_walk_start(graph, entity_err);
 529
 530         while ((entity_err = media_graph_walk_next(graph))) {
 531                 /* Sanity check for negative stream_count */
 532                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 533                         entity_err->stream_count--;
 534                         if (entity_err->stream_count == 0)
 535                                 entity_err->pipe = NULL;
 536                 }
 537
 538                 /*
 539                  * We haven't increased stream_count further than this
 540                  * so we quit here.
 541                  */
 542                 if (entity_err == entity)
 543                         break;
 544         }
 545
 546 error_graph_walk_start:
 547         if (!--pipe->streaming_count)
 548                 media_graph_walk_cleanup(graph);
 549
 550         return ret;
 551 }
 552 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 553
 554 __must_check int media_pipeline_start(struct media_entity *entity,
 555                                       struct media_pipeline *pipe)
 556 {
 557         struct media_device *mdev = entity->graph_obj.mdev;
 558         int ret;
 559
 560         mutex_lock(&mdev->graph_mutex);
 561         ret = __media_pipeline_start(entity, pipe);
 562         mutex_unlock(&mdev->graph_mutex);
 563         return ret;
 564 }
 565 EXPORT_SYMBOL_GPL(media_pipeline_start);
 566
 567 void __media_pipeline_stop(struct media_entity *entity)
 568 {
 569         struct media_graph *graph = &entity->pipe->graph;
 570         struct media_pipeline *pipe = entity->pipe;
 571
 572         /*
 573          * If the following check fails, the driver has performed an
 574          * unbalanced call to media_pipeline_stop()
 575          */
 576         if (WARN_ON(!pipe))
 577                 return;
 578
 579         media_graph_walk_start(graph, entity);
 580
 581         while ((entity = media_graph_walk_next(graph))) {
 582                 /* Sanity check for negative stream_count */
 583                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 584                         entity->stream_count--;
 585                         if (entity->stream_count == 0)
 586                                 entity->pipe = NULL;
 587                 }
 588         }
 589
 590         if (!--pipe->streaming_count)
 591                 media_graph_walk_cleanup(graph);
 592
 593 }
 594 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 595
 596 void media_pipeline_stop(struct media_entity *entity)
 597 {
 598         struct media_device *mdev = entity->graph_obj.mdev;
 599
 600         mutex_lock(&mdev->graph_mutex);
 601         __media_pipeline_stop(entity);
 602         mutex_unlock(&mdev->graph_mutex);
 603 }
 604 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 605
 606 /* -----------------------------------------------------------------------------
 607  * Module use count
 608  */
 609
 610 struct media_entity *media_entity_get(struct media_entity *entity)
 611 {
 612         if (entity == NULL)
 613                 return NULL;
 614
 615         if (entity->graph_obj.mdev->dev &&
 616             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 617                 return NULL;
 618
 619         return entity;
 620 }
 621 EXPORT_SYMBOL_GPL(media_entity_get);
 622
 623 void media_entity_put(struct media_entity *entity)
 624 {
 625         if (entity == NULL)
 626                 return;
 627
 628         if (entity->graph_obj.mdev->dev)
 629                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 630 }
 631 EXPORT_SYMBOL_GPL(media_entity_put);
 632
 633 /* -----------------------------------------------------------------------------
 634  * Links management
 635  */
 636
 637 static struct media_link *media_add_link(struct list_head *head)
 638 {
 639         struct media_link *link;
 640
 641         link = kzalloc(sizeof(*link), GFP_KERNEL);
 642         if (link == NULL)
 643                 return NULL;
 644
 645         list_add_tail(&link->list, head);
 646
 647         return link;
 648 }
 649
 650 static void __media_entity_remove_link(struct media_entity *entity,
 651                                        struct media_link *link)
 652 {
 653         struct media_link *rlink, *tmp;
 654         struct media_entity *remote;
 655
 656         if (link->source->entity == entity)
 657                 remote = link->sink->entity;
 658         else
 659                 remote = link->source->entity;
 660
 661         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 662                 if (rlink != link->reverse)
 663                         continue;
 664
 665                 if (link->source->entity == entity)
 666                         remote->num_backlinks--;
 667
 668                 /* Remove the remote link */
 669                 list_del(&rlink->list);
 670                 media_gobj_destroy(&rlink->graph_obj);
 671                 kfree(rlink);
 672
 673                 if (--remote->num_links == 0)
 674                         break;
 675         }
 676         list_del(&link->list);
 677         media_gobj_destroy(&link->graph_obj);
 678         kfree(link);
 679 }
 680
 681 int
 682 media_create_pad_link(struct media_entity *source, u16 source_pad,
 683                          struct media_entity *sink, u16 sink_pad, u32 flags)
 684 {
 685         struct media_link *link;
 686         struct media_link *backlink;
 687
 688         BUG_ON(source == NULL || sink == NULL);
 689         BUG_ON(source_pad >= source->num_pads);
 690         BUG_ON(sink_pad >= sink->num_pads);
 691
 692         link = media_add_link(&source->links);
 693         if (link == NULL)
 694                 return -ENOMEM;
 695
 696         link->source = &source->pads[source_pad];
 697         link->sink = &sink->pads[sink_pad];
 698         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 699
 700         /* Initialize graph object embedded at the new link */
 701         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 702                         &link->graph_obj);
 703
 704         /* Create the backlink. Backlinks are used to help graph traversal and
 705          * are not reported to userspace.
 706          */
 707         backlink = media_add_link(&sink->links);
 708         if (backlink == NULL) {
 709                 __media_entity_remove_link(source, link);
 710                 return -ENOMEM;
 711         }
 712
 713         backlink->source = &source->pads[source_pad];
 714         backlink->sink = &sink->pads[sink_pad];
 715         backlink->flags = flags;
 716         backlink->is_backlink = true;
 717
 718         /* Initialize graph object embedded at the new link */
 719         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 720                         &backlink->graph_obj);
 721
 722         link->reverse = backlink;
 723         backlink->reverse = link;
 724
 725         sink->num_backlinks++;
 726         sink->num_links++;
 727         source->num_links++;
 728
 729         return 0;
 730 }
 731 EXPORT_SYMBOL_GPL(media_create_pad_link);
 732
 733 int media_create_pad_links(const struct media_device *mdev,
 734                            const u32 source_function,
 735                            struct media_entity *source,
 736                            const u16 source_pad,
 737                            const u32 sink_function,
 738                            struct media_entity *sink,
 739                            const u16 sink_pad,
 740                            u32 flags,
 741                            const bool allow_both_undefined)
 742 {
 743         struct media_entity *entity;
 744         unsigned function;
 745         int ret;
 746
 747         /* Trivial case: 1:1 relation */
 748         if (source && sink)
 749                 return media_create_pad_link(source, source_pad,
 750                                              sink, sink_pad, flags);
 751
 752         /* Worse case scenario: n:n relation */
 753         if (!source && !sink) {
 754                 if (!allow_both_undefined)
 755                         return 0;
 756                 media_device_for_each_entity(source, mdev) {
 757                         if (source->function != source_function)
 758                                 continue;
 759                         media_device_for_each_entity(sink, mdev) {
 760                                 if (sink->function != sink_function)
 761                                         continue;
 762                                 ret = media_create_pad_link(source, source_pad,
 763                                                             sink, sink_pad,
 764                                                             flags);
 765                                 if (ret)
 766                                         return ret;
 767                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 768                                            MEDIA_LNK_FL_IMMUTABLE);
 769                         }
 770                 }
 771                 return 0;
 772         }
 773
 774         /* Handle 1:n and n:1 cases */
 775         if (source)
 776                 function = sink_function;
 777         else
 778                 function = source_function;
 779
 780         media_device_for_each_entity(entity, mdev) {
 781                 if (entity->function != function)
 782                         continue;
 783
 784                 if (source)
 785                         ret = media_create_pad_link(source, source_pad,
 786                                                     entity, sink_pad, flags);
 787                 else
 788                         ret = media_create_pad_link(entity, source_pad,
 789                                                     sink, sink_pad, flags);
 790                 if (ret)
 791                         return ret;
 792                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 793         }
 794         return 0;
 795 }
 796 EXPORT_SYMBOL_GPL(media_create_pad_links);
 797
 798 void __media_entity_remove_links(struct media_entity *entity)
 799 {
 800         struct media_link *link, *tmp;
 801
 802         list_for_each_entry_safe(link, tmp, &entity->links, list)
 803                 __media_entity_remove_link(entity, link);
 804
 805         entity->num_links = 0;
 806         entity->num_backlinks = 0;
 807 }
 808 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 809
 810 void media_entity_remove_links(struct media_entity *entity)
 811 {
 812         struct media_device *mdev = entity->graph_obj.mdev;
 813
 814         /* Do nothing if the entity is not registered. */
 815         if (mdev == NULL)
 816                 return;
 817
 818         mutex_lock(&mdev->graph_mutex);
 819         __media_entity_remove_links(entity);
 820         mutex_unlock(&mdev->graph_mutex);
 821 }
 822 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 823
 824 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 825 {
 826         int ret;
 827
 828         /* Notify both entities. */
 829         ret = media_entity_call(link->source->entity, link_setup,
 830                                 link->source, link->sink, flags);
 831         if (ret < 0 && ret != -ENOIOCTLCMD)
 832                 return ret;
 833
 834         ret = media_entity_call(link->sink->entity, link_setup,
 835                                 link->sink, link->source, flags);
 836         if (ret < 0 && ret != -ENOIOCTLCMD) {
 837                 media_entity_call(link->source->entity, link_setup,
 838                                   link->source, link->sink, link->flags);
 839                 return ret;
 840         }
 841
 842         link->flags = flags;
 843         link->reverse->flags = link->flags;
 844
 845         return 0;
 846 }
 847
 848 int __media_entity_setup_link(struct media_link *link, u32 flags)
 849 {
 850         const u32 mask = MEDIA_LNK_FL_ENABLED;
 851         struct media_device *mdev;
 852         struct media_entity *source, *sink;
 853         int ret = -EBUSY;
 854
 855         if (link == NULL)
 856                 return -EINVAL;
 857
 858         /* The non-modifiable link flags must not be modified. */
 859         if ((link->flags & ~mask) != (flags & ~mask))
 860                 return -EINVAL;
 861
 862         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 863                 return link->flags == flags ? 0 : -EINVAL;
 864
 865         if (link->flags == flags)
 866                 return 0;
 867
 868         source = link->source->entity;
 869         sink = link->sink->entity;
 870
 871         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 872             (source->stream_count || sink->stream_count))
 873                 return -EBUSY;
 874
 875         mdev = source->graph_obj.mdev;
 876
 877         if (mdev->ops && mdev->ops->link_notify) {
 878                 ret = mdev->ops->link_notify(link, flags,
 879                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 880                 if (ret < 0)
 881                         return ret;
 882         }
 883
 884         ret = __media_entity_setup_link_notify(link, flags);
 885
 886         if (mdev->ops && mdev->ops->link_notify)
 887                 mdev->ops->link_notify(link, flags,
 888                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 889
 890         return ret;
 891 }
 892 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 893
 894 int media_entity_setup_link(struct media_link *link, u32 flags)
 895 {
 896         int ret;
 897
 898         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 899         ret = __media_entity_setup_link(link, flags);
 900         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 901
 902         return ret;
 903 }
 904 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 905
 906 struct media_link *
 907 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 908 {
 909         struct media_link *link;
 910
 911         list_for_each_entry(link, &source->entity->links, list) {
 912                 if (link->source->entity == source->entity &&
 913                     link->source->index == source->index &&
 914                     link->sink->entity == sink->entity &&
 915                     link->sink->index == sink->index)
 916                         return link;
 917         }
 918
 919         return NULL;
 920 }
 921 EXPORT_SYMBOL_GPL(media_entity_find_link);
 922
 923 struct media_pad *media_entity_remote_pad(const struct media_pad *pad)
 924 {
 925         struct media_link *link;
 926
 927         list_for_each_entry(link, &pad->entity->links, list) {
 928                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 929                         continue;
 930
 931                 if (link->source == pad)
 932                         return link->sink;
 933
 934                 if (link->sink == pad)
 935                         return link->source;
 936         }
 937
 938         return NULL;
 939
 940 }
 941 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 942
 943 static void media_interface_init(struct media_device *mdev,
 944                                  struct media_interface *intf,
 945                                  u32 gobj_type,
 946                                  u32 intf_type, u32 flags)
 947 {
 948         intf->type = intf_type;
 949         intf->flags = flags;
 950         INIT_LIST_HEAD(&intf->links);
 951
 952         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 953 }
 954
 955 /* Functions related to the media interface via device nodes */
 956
 957 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 958                                                 u32 type, u32 flags,
 959                                                 u32 major, u32 minor)
 960 {
 961         struct media_intf_devnode *devnode;
 962
 963         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 964         if (!devnode)
 965                 return NULL;
 966
 967         devnode->major = major;
 968         devnode->minor = minor;
 969
 970         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 971                              type, flags);
 972
 973         return devnode;
 974 }
 975 EXPORT_SYMBOL_GPL(media_devnode_create);
 976
 977 void media_devnode_remove(struct media_intf_devnode *devnode)
 978 {
 979         media_remove_intf_links(&devnode->intf);
 980         media_gobj_destroy(&devnode->intf.graph_obj);
 981         kfree(devnode);
 982 }
 983 EXPORT_SYMBOL_GPL(media_devnode_remove);
 984
 985 struct media_link *media_create_intf_link(struct media_entity *entity,
 986                                             struct media_interface *intf,
 987                                             u32 flags)
 988 {
 989         struct media_link *link;
 990
 991         link = media_add_link(&intf->links);
 992         if (link == NULL)
 993                 return NULL;
 994
 995         link->intf = intf;
 996         link->entity = entity;
 997         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 998
 999         /* Initialize graph object embedded at the new link */
1000         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
1001                         &link->graph_obj);
1002
1003         return link;
1004 }
1005 EXPORT_SYMBOL_GPL(media_create_intf_link);
1006
1007 void __media_remove_intf_link(struct media_link *link)
1008 {
1009         list_del(&link->list);
1010         media_gobj_destroy(&link->graph_obj);
1011         kfree(link);
1012 }
1013 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
1014
1015 void media_remove_intf_link(struct media_link *link)
1016 {
1017         struct media_device *mdev = link->graph_obj.mdev;
1018
1019         /* Do nothing if the intf is not registered. */
1020         if (mdev == NULL)
1021                 return;
1022
1023         mutex_lock(&mdev->graph_mutex);
1024         __media_remove_intf_link(link);
1025         mutex_unlock(&mdev->graph_mutex);
1026 }
1027 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1028
1029 void __media_remove_intf_links(struct media_interface *intf)
1030 {
1031         struct media_link *link, *tmp;
1032
1033         list_for_each_entry_safe(link, tmp, &intf->links, list)
1034                 __media_remove_intf_link(link);
1035
1036 }
1037 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1038
1039 void media_remove_intf_links(struct media_interface *intf)
1040 {
1041         struct media_device *mdev = intf->graph_obj.mdev;
1042
1043         /* Do nothing if the intf is not registered. */
1044         if (mdev == NULL)
1045                 return;
1046
1047         mutex_lock(&mdev->graph_mutex);
1048         __media_remove_intf_links(intf);
1049         mutex_unlock(&mdev->graph_mutex);
1050 }
1051 EXPORT_SYMBOL_GPL(media_remove_intf_links);