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  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/bitmap.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <media/media-entity.h>
  27 #include <media/media-device.h>
  28
  29 static inline const char *gobj_type(enum media_gobj_type type)
  30 {
  31         switch (type) {
  32         case MEDIA_GRAPH_ENTITY:
  33                 return "entity";
  34         case MEDIA_GRAPH_PAD:
  35                 return "pad";
  36         case MEDIA_GRAPH_LINK:
  37                 return "link";
  38         case MEDIA_GRAPH_INTF_DEVNODE:
  39                 return "intf-devnode";
  40         default:
  41                 return "unknown";
  42         }
  43 }
  44
  45 static inline const char *intf_type(struct media_interface *intf)
  46 {
  47         switch (intf->type) {
  48         case MEDIA_INTF_T_DVB_FE:
  49                 return "dvb-frontend";
  50         case MEDIA_INTF_T_DVB_DEMUX:
  51                 return "dvb-demux";
  52         case MEDIA_INTF_T_DVB_DVR:
  53                 return "dvb-dvr";
  54         case MEDIA_INTF_T_DVB_CA:
  55                 return  "dvb-ca";
  56         case MEDIA_INTF_T_DVB_NET:
  57                 return "dvb-net";
  58         case MEDIA_INTF_T_V4L_VIDEO:
  59                 return "v4l-video";
  60         case MEDIA_INTF_T_V4L_VBI:
  61                 return "v4l-vbi";
  62         case MEDIA_INTF_T_V4L_RADIO:
  63                 return "v4l-radio";
  64         case MEDIA_INTF_T_V4L_SUBDEV:
  65                 return "v4l-subdev";
  66         case MEDIA_INTF_T_V4L_SWRADIO:
  67                 return "v4l-swradio";
  68         case MEDIA_INTF_T_V4L_TOUCH:
  69                 return "v4l-touch";
  70         case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
  71                 return "alsa-pcm-capture";
  72         case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
  73                 return "alsa-pcm-playback";
  74         case MEDIA_INTF_T_ALSA_CONTROL:
  75                 return "alsa-control";
  76         case MEDIA_INTF_T_ALSA_COMPRESS:
  77                 return "alsa-compress";
  78         case MEDIA_INTF_T_ALSA_RAWMIDI:
  79                 return "alsa-rawmidi";
  80         case MEDIA_INTF_T_ALSA_HWDEP:
  81                 return "alsa-hwdep";
  82         case MEDIA_INTF_T_ALSA_SEQUENCER:
  83                 return "alsa-sequencer";
  84         case MEDIA_INTF_T_ALSA_TIMER:
  85                 return "alsa-timer";
  86         default:
  87                 return "unknown-intf";
  88         }
  89 };
  90
  91 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  92                                           int idx_max)
  93 {
  94         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  95         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  96                                  GFP_KERNEL);
  97         if (!ent_enum->bmap)
  98                 return -ENOMEM;
  99
 100         bitmap_zero(ent_enum->bmap, idx_max);
 101         ent_enum->idx_max = idx_max;
 102
 103         return 0;
 104 }
 105 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
 106
 107 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
 108 {
 109         kfree(ent_enum->bmap);
 110 }
 111 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
 112
 113 /**
 114  *  dev_dbg_obj - Prints in debug mode a change on some object
 115  *
 116  * @event_name: Name of the event to report. Could be __func__
 117  * @gobj:       Pointer to the object
 118  *
 119  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 120  * won't produce any code.
 121  */
 122 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 123 {
 124 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 125         switch (media_type(gobj)) {
 126         case MEDIA_GRAPH_ENTITY:
 127                 dev_dbg(gobj->mdev->dev,
 128                         "%s id %u: entity '%s'\n",
 129                         event_name, media_id(gobj),
 130                         gobj_to_entity(gobj)->name);
 131                 break;
 132         case MEDIA_GRAPH_LINK:
 133         {
 134                 struct media_link *link = gobj_to_link(gobj);
 135
 136                 dev_dbg(gobj->mdev->dev,
 137                         "%s id %u: %s link id %u ==> id %u\n",
 138                         event_name, media_id(gobj),
 139                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 140                                 "data" : "interface",
 141                         media_id(link->gobj0),
 142                         media_id(link->gobj1));
 143                 break;
 144         }
 145         case MEDIA_GRAPH_PAD:
 146         {
 147                 struct media_pad *pad = gobj_to_pad(gobj);
 148
 149                 dev_dbg(gobj->mdev->dev,
 150                         "%s id %u: %s%spad '%s':%d\n",
 151                         event_name, media_id(gobj),
 152                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 153                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 154                         pad->entity->name, pad->index);
 155                 break;
 156         }
 157         case MEDIA_GRAPH_INTF_DEVNODE:
 158         {
 159                 struct media_interface *intf = gobj_to_intf(gobj);
 160                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 161
 162                 dev_dbg(gobj->mdev->dev,
 163                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 164                         event_name, media_id(gobj),
 165                         intf_type(intf),
 166                         devnode->major, devnode->minor);
 167                 break;
 168         }
 169         }
 170 #endif
 171 }
 172
 173 void media_gobj_create(struct media_device *mdev,
 174                            enum media_gobj_type type,
 175                            struct media_gobj *gobj)
 176 {
 177         BUG_ON(!mdev);
 178
 179         gobj->mdev = mdev;
 180
 181         /* Create a per-type unique object ID */
 182         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 183
 184         switch (type) {
 185         case MEDIA_GRAPH_ENTITY:
 186                 list_add_tail(&gobj->list, &mdev->entities);
 187                 break;
 188         case MEDIA_GRAPH_PAD:
 189                 list_add_tail(&gobj->list, &mdev->pads);
 190                 break;
 191         case MEDIA_GRAPH_LINK:
 192                 list_add_tail(&gobj->list, &mdev->links);
 193                 break;
 194         case MEDIA_GRAPH_INTF_DEVNODE:
 195                 list_add_tail(&gobj->list, &mdev->interfaces);
 196                 break;
 197         }
 198
 199         mdev->topology_version++;
 200
 201         dev_dbg_obj(__func__, gobj);
 202 }
 203
 204 void media_gobj_destroy(struct media_gobj *gobj)
 205 {
 206         dev_dbg_obj(__func__, gobj);
 207
 208         /* Do nothing if the object is not linked. */
 209         if (gobj->mdev == NULL)
 210                 return;
 211
 212         gobj->mdev->topology_version++;
 213
 214         /* Remove the object from mdev list */
 215         list_del(&gobj->list);
 216
 217         gobj->mdev = NULL;
 218 }
 219
 220 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 221                            struct media_pad *pads)
 222 {
 223         struct media_device *mdev = entity->graph_obj.mdev;
 224         unsigned int i;
 225
 226         entity->num_pads = num_pads;
 227         entity->pads = pads;
 228
 229         if (mdev)
 230                 mutex_lock(&mdev->graph_mutex);
 231
 232         for (i = 0; i < num_pads; i++) {
 233                 pads[i].entity = entity;
 234                 pads[i].index = i;
 235                 if (mdev)
 236                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 237                                         &entity->pads[i].graph_obj);
 238         }
 239
 240         if (mdev)
 241                 mutex_unlock(&mdev->graph_mutex);
 242
 243         return 0;
 244 }
 245 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 246
 247 /* -----------------------------------------------------------------------------
 248  * Graph traversal
 249  */
 250
 251 static struct media_entity *
 252 media_entity_other(struct media_entity *entity, struct media_link *link)
 253 {
 254         if (link->source->entity == entity)
 255                 return link->sink->entity;
 256         else
 257                 return link->source->entity;
 258 }
 259
 260 /* push an entity to traversal stack */
 261 static void stack_push(struct media_entity_graph *graph,
 262                        struct media_entity *entity)
 263 {
 264         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 265                 WARN_ON(1);
 266                 return;
 267         }
 268         graph->top++;
 269         graph->stack[graph->top].link = entity->links.next;
 270         graph->stack[graph->top].entity = entity;
 271 }
 272
 273 static struct media_entity *stack_pop(struct media_entity_graph *graph)
 274 {
 275         struct media_entity *entity;
 276
 277         entity = graph->stack[graph->top].entity;
 278         graph->top--;
 279
 280         return entity;
 281 }
 282
 283 #define link_top(en)    ((en)->stack[(en)->top].link)
 284 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 285
 286 /*
 287  * TODO: Get rid of this.
 288  */
 289 #define MEDIA_ENTITY_MAX_PADS           512
 290
 291 /**
 292  * media_entity_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_entity_graph_walk_free().
 299  *
 300  * Returns error on failure, zero on success.
 301  */
 302 __must_check int media_entity_graph_walk_init(
 303         struct media_entity_graph *graph, struct media_device *mdev)
 304 {
 305         return media_entity_enum_init(&graph->ent_enum, mdev);
 306 }
 307 EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
 308
 309 /**
 310  * media_entity_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_entity_graph_walk_cleanup(struct media_entity_graph *graph)
 314 {
 315         media_entity_enum_cleanup(&graph->ent_enum);
 316 }
 317 EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
 318
 319 void media_entity_graph_walk_start(struct media_entity_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 }
 329 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
 330
 331 struct media_entity *
 332 media_entity_graph_walk_next(struct media_entity_graph *graph)
 333 {
 334         if (stack_top(graph) == NULL)
 335                 return NULL;
 336
 337         /*
 338          * Depth first search. Push entity to stack and continue from
 339          * top of the stack until no more entities on the level can be
 340          * found.
 341          */
 342         while (link_top(graph) != &stack_top(graph)->links) {
 343                 struct media_entity *entity = stack_top(graph);
 344                 struct media_link *link;
 345                 struct media_entity *next;
 346
 347                 link = list_entry(link_top(graph), typeof(*link), list);
 348
 349                 /* The link is not enabled so we do not follow. */
 350                 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 351                         link_top(graph) = link_top(graph)->next;
 352                         continue;
 353                 }
 354
 355                 /* Get the entity in the other end of the link . */
 356                 next = media_entity_other(entity, link);
 357
 358                 /* Has the entity already been visited? */
 359                 if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 360                         link_top(graph) = link_top(graph)->next;
 361                         continue;
 362                 }
 363
 364                 /* Push the new entity to stack and start over. */
 365                 link_top(graph) = link_top(graph)->next;
 366                 stack_push(graph, next);
 367         }
 368
 369         return stack_pop(graph);
 370 }
 371 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
 372
 373 /* -----------------------------------------------------------------------------
 374  * Pipeline management
 375  */
 376
 377 __must_check int __media_entity_pipeline_start(struct media_entity *entity,
 378                                                struct media_pipeline *pipe)
 379 {
 380         struct media_device *mdev = entity->graph_obj.mdev;
 381         struct media_entity_graph *graph = &pipe->graph;
 382         struct media_entity *entity_err = entity;
 383         struct media_link *link;
 384         int ret;
 385
 386         if (!pipe->streaming_count++) {
 387                 ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 388                 if (ret)
 389                         goto error_graph_walk_start;
 390         }
 391
 392         media_entity_graph_walk_start(&pipe->graph, entity);
 393
 394         while ((entity = media_entity_graph_walk_next(graph))) {
 395                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 396                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 397
 398                 entity->stream_count++;
 399
 400                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 401                         ret = -EBUSY;
 402                         goto error;
 403                 }
 404
 405                 entity->pipe = pipe;
 406
 407                 /* Already streaming --- no need to check. */
 408                 if (entity->stream_count > 1)
 409                         continue;
 410
 411                 if (!entity->ops || !entity->ops->link_validate)
 412                         continue;
 413
 414                 bitmap_zero(active, entity->num_pads);
 415                 bitmap_fill(has_no_links, entity->num_pads);
 416
 417                 list_for_each_entry(link, &entity->links, list) {
 418                         struct media_pad *pad = link->sink->entity == entity
 419                                                 ? link->sink : link->source;
 420
 421                         /* Mark that a pad is connected by a link. */
 422                         bitmap_clear(has_no_links, pad->index, 1);
 423
 424                         /*
 425                          * Pads that either do not need to connect or
 426                          * are connected through an enabled link are
 427                          * fine.
 428                          */
 429                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 430                             link->flags & MEDIA_LNK_FL_ENABLED)
 431                                 bitmap_set(active, pad->index, 1);
 432
 433                         /*
 434                          * Link validation will only take place for
 435                          * sink ends of the link that are enabled.
 436                          */
 437                         if (link->sink != pad ||
 438                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 439                                 continue;
 440
 441                         ret = entity->ops->link_validate(link);
 442                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 443                                 dev_dbg(entity->graph_obj.mdev->dev,
 444                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 445                                         link->source->entity->name,
 446                                         link->source->index,
 447                                         entity->name, link->sink->index, ret);
 448                                 goto error;
 449                         }
 450                 }
 451
 452                 /* Either no links or validated links are fine. */
 453                 bitmap_or(active, active, has_no_links, entity->num_pads);
 454
 455                 if (!bitmap_full(active, entity->num_pads)) {
 456                         ret = -ENOLINK;
 457                         dev_dbg(entity->graph_obj.mdev->dev,
 458                                 "\"%s\":%u must be connected by an enabled link\n",
 459                                 entity->name,
 460                                 (unsigned)find_first_zero_bit(
 461                                         active, entity->num_pads));
 462                         goto error;
 463                 }
 464         }
 465
 466         return 0;
 467
 468 error:
 469         /*
 470          * Link validation on graph failed. We revert what we did and
 471          * return the error.
 472          */
 473         media_entity_graph_walk_start(graph, entity_err);
 474
 475         while ((entity_err = media_entity_graph_walk_next(graph))) {
 476                 /* don't let the stream_count go negative */
 477                 if (entity->stream_count > 0) {
 478                         entity_err->stream_count--;
 479                         if (entity_err->stream_count == 0)
 480                                 entity_err->pipe = NULL;
 481                 }
 482
 483                 /*
 484                  * We haven't increased stream_count further than this
 485                  * so we quit here.
 486                  */
 487                 if (entity_err == entity)
 488                         break;
 489         }
 490
 491 error_graph_walk_start:
 492         if (!--pipe->streaming_count)
 493                 media_entity_graph_walk_cleanup(graph);
 494
 495         return ret;
 496 }
 497 EXPORT_SYMBOL_GPL(__media_entity_pipeline_start);
 498
 499 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 500                                              struct media_pipeline *pipe)
 501 {
 502         struct media_device *mdev = entity->graph_obj.mdev;
 503         int ret;
 504
 505         mutex_lock(&mdev->graph_mutex);
 506         ret = __media_entity_pipeline_start(entity, pipe);
 507         mutex_unlock(&mdev->graph_mutex);
 508         return ret;
 509 }
 510 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 511
 512 void __media_entity_pipeline_stop(struct media_entity *entity)
 513 {
 514         struct media_entity_graph *graph = &entity->pipe->graph;
 515         struct media_pipeline *pipe = entity->pipe;
 516
 517
 518         WARN_ON(!pipe->streaming_count);
 519         media_entity_graph_walk_start(graph, entity);
 520
 521         while ((entity = media_entity_graph_walk_next(graph))) {
 522                 /* don't let the stream_count go negative */
 523                 if (entity->stream_count > 0) {
 524                         entity->stream_count--;
 525                         if (entity->stream_count == 0)
 526                                 entity->pipe = NULL;
 527                 }
 528         }
 529
 530         if (!--pipe->streaming_count)
 531                 media_entity_graph_walk_cleanup(graph);
 532
 533 }
 534 EXPORT_SYMBOL_GPL(__media_entity_pipeline_stop);
 535
 536 void media_entity_pipeline_stop(struct media_entity *entity)
 537 {
 538         struct media_device *mdev = entity->graph_obj.mdev;
 539
 540         mutex_lock(&mdev->graph_mutex);
 541         __media_entity_pipeline_stop(entity);
 542         mutex_unlock(&mdev->graph_mutex);
 543 }
 544 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
 545
 546 /* -----------------------------------------------------------------------------
 547  * Module use count
 548  */
 549
 550 struct media_entity *media_entity_get(struct media_entity *entity)
 551 {
 552         if (entity == NULL)
 553                 return NULL;
 554
 555         if (entity->graph_obj.mdev->dev &&
 556             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 557                 return NULL;
 558
 559         return entity;
 560 }
 561 EXPORT_SYMBOL_GPL(media_entity_get);
 562
 563 void media_entity_put(struct media_entity *entity)
 564 {
 565         if (entity == NULL)
 566                 return;
 567
 568         if (entity->graph_obj.mdev->dev)
 569                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 570 }
 571 EXPORT_SYMBOL_GPL(media_entity_put);
 572
 573 /* -----------------------------------------------------------------------------
 574  * Links management
 575  */
 576
 577 static struct media_link *media_add_link(struct list_head *head)
 578 {
 579         struct media_link *link;
 580
 581         link = kzalloc(sizeof(*link), GFP_KERNEL);
 582         if (link == NULL)
 583                 return NULL;
 584
 585         list_add_tail(&link->list, head);
 586
 587         return link;
 588 }
 589
 590 static void __media_entity_remove_link(struct media_entity *entity,
 591                                        struct media_link *link)
 592 {
 593         struct media_link *rlink, *tmp;
 594         struct media_entity *remote;
 595
 596         if (link->source->entity == entity)
 597                 remote = link->sink->entity;
 598         else
 599                 remote = link->source->entity;
 600
 601         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 602                 if (rlink != link->reverse)
 603                         continue;
 604
 605                 if (link->source->entity == entity)
 606                         remote->num_backlinks--;
 607
 608                 /* Remove the remote link */
 609                 list_del(&rlink->list);
 610                 media_gobj_destroy(&rlink->graph_obj);
 611                 kfree(rlink);
 612
 613                 if (--remote->num_links == 0)
 614                         break;
 615         }
 616         list_del(&link->list);
 617         media_gobj_destroy(&link->graph_obj);
 618         kfree(link);
 619 }
 620
 621 int
 622 media_create_pad_link(struct media_entity *source, u16 source_pad,
 623                          struct media_entity *sink, u16 sink_pad, u32 flags)
 624 {
 625         struct media_link *link;
 626         struct media_link *backlink;
 627
 628         BUG_ON(source == NULL || sink == NULL);
 629         BUG_ON(source_pad >= source->num_pads);
 630         BUG_ON(sink_pad >= sink->num_pads);
 631
 632         link = media_add_link(&source->links);
 633         if (link == NULL)
 634                 return -ENOMEM;
 635
 636         link->source = &source->pads[source_pad];
 637         link->sink = &sink->pads[sink_pad];
 638         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 639
 640         /* Initialize graph object embedded at the new link */
 641         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 642                         &link->graph_obj);
 643
 644         /* Create the backlink. Backlinks are used to help graph traversal and
 645          * are not reported to userspace.
 646          */
 647         backlink = media_add_link(&sink->links);
 648         if (backlink == NULL) {
 649                 __media_entity_remove_link(source, link);
 650                 return -ENOMEM;
 651         }
 652
 653         backlink->source = &source->pads[source_pad];
 654         backlink->sink = &sink->pads[sink_pad];
 655         backlink->flags = flags;
 656         backlink->is_backlink = true;
 657
 658         /* Initialize graph object embedded at the new link */
 659         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 660                         &backlink->graph_obj);
 661
 662         link->reverse = backlink;
 663         backlink->reverse = link;
 664
 665         sink->num_backlinks++;
 666         sink->num_links++;
 667         source->num_links++;
 668
 669         return 0;
 670 }
 671 EXPORT_SYMBOL_GPL(media_create_pad_link);
 672
 673 int media_create_pad_links(const struct media_device *mdev,
 674                            const u32 source_function,
 675                            struct media_entity *source,
 676                            const u16 source_pad,
 677                            const u32 sink_function,
 678                            struct media_entity *sink,
 679                            const u16 sink_pad,
 680                            u32 flags,
 681                            const bool allow_both_undefined)
 682 {
 683         struct media_entity *entity;
 684         unsigned function;
 685         int ret;
 686
 687         /* Trivial case: 1:1 relation */
 688         if (source && sink)
 689                 return media_create_pad_link(source, source_pad,
 690                                              sink, sink_pad, flags);
 691
 692         /* Worse case scenario: n:n relation */
 693         if (!source && !sink) {
 694                 if (!allow_both_undefined)
 695                         return 0;
 696                 media_device_for_each_entity(source, mdev) {
 697                         if (source->function != source_function)
 698                                 continue;
 699                         media_device_for_each_entity(sink, mdev) {
 700                                 if (sink->function != sink_function)
 701                                         continue;
 702                                 ret = media_create_pad_link(source, source_pad,
 703                                                             sink, sink_pad,
 704                                                             flags);
 705                                 if (ret)
 706                                         return ret;
 707                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 708                                            MEDIA_LNK_FL_IMMUTABLE);
 709                         }
 710                 }
 711                 return 0;
 712         }
 713
 714         /* Handle 1:n and n:1 cases */
 715         if (source)
 716                 function = sink_function;
 717         else
 718                 function = source_function;
 719
 720         media_device_for_each_entity(entity, mdev) {
 721                 if (entity->function != function)
 722                         continue;
 723
 724                 if (source)
 725                         ret = media_create_pad_link(source, source_pad,
 726                                                     entity, sink_pad, flags);
 727                 else
 728                         ret = media_create_pad_link(entity, source_pad,
 729                                                     sink, sink_pad, flags);
 730                 if (ret)
 731                         return ret;
 732                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 733         }
 734         return 0;
 735 }
 736 EXPORT_SYMBOL_GPL(media_create_pad_links);
 737
 738 void __media_entity_remove_links(struct media_entity *entity)
 739 {
 740         struct media_link *link, *tmp;
 741
 742         list_for_each_entry_safe(link, tmp, &entity->links, list)
 743                 __media_entity_remove_link(entity, link);
 744
 745         entity->num_links = 0;
 746         entity->num_backlinks = 0;
 747 }
 748 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 749
 750 void media_entity_remove_links(struct media_entity *entity)
 751 {
 752         struct media_device *mdev = entity->graph_obj.mdev;
 753
 754         /* Do nothing if the entity is not registered. */
 755         if (mdev == NULL)
 756                 return;
 757
 758         mutex_lock(&mdev->graph_mutex);
 759         __media_entity_remove_links(entity);
 760         mutex_unlock(&mdev->graph_mutex);
 761 }
 762 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 763
 764 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 765 {
 766         int ret;
 767
 768         /* Notify both entities. */
 769         ret = media_entity_call(link->source->entity, link_setup,
 770                                 link->source, link->sink, flags);
 771         if (ret < 0 && ret != -ENOIOCTLCMD)
 772                 return ret;
 773
 774         ret = media_entity_call(link->sink->entity, link_setup,
 775                                 link->sink, link->source, flags);
 776         if (ret < 0 && ret != -ENOIOCTLCMD) {
 777                 media_entity_call(link->source->entity, link_setup,
 778                                   link->source, link->sink, link->flags);
 779                 return ret;
 780         }
 781
 782         link->flags = flags;
 783         link->reverse->flags = link->flags;
 784
 785         return 0;
 786 }
 787
 788 int __media_entity_setup_link(struct media_link *link, u32 flags)
 789 {
 790         const u32 mask = MEDIA_LNK_FL_ENABLED;
 791         struct media_device *mdev;
 792         struct media_entity *source, *sink;
 793         int ret = -EBUSY;
 794
 795         if (link == NULL)
 796                 return -EINVAL;
 797
 798         /* The non-modifiable link flags must not be modified. */
 799         if ((link->flags & ~mask) != (flags & ~mask))
 800                 return -EINVAL;
 801
 802         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 803                 return link->flags == flags ? 0 : -EINVAL;
 804
 805         if (link->flags == flags)
 806                 return 0;
 807
 808         source = link->source->entity;
 809         sink = link->sink->entity;
 810
 811         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 812             (source->stream_count || sink->stream_count))
 813                 return -EBUSY;
 814
 815         mdev = source->graph_obj.mdev;
 816
 817         if (mdev->ops && mdev->ops->link_notify) {
 818                 ret = mdev->ops->link_notify(link, flags,
 819                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 820                 if (ret < 0)
 821                         return ret;
 822         }
 823
 824         ret = __media_entity_setup_link_notify(link, flags);
 825
 826         if (mdev->ops && mdev->ops->link_notify)
 827                 mdev->ops->link_notify(link, flags,
 828                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 829
 830         return ret;
 831 }
 832 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 833
 834 int media_entity_setup_link(struct media_link *link, u32 flags)
 835 {
 836         int ret;
 837
 838         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 839         ret = __media_entity_setup_link(link, flags);
 840         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 841
 842         return ret;
 843 }
 844 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 845
 846 struct media_link *
 847 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 848 {
 849         struct media_link *link;
 850
 851         list_for_each_entry(link, &source->entity->links, list) {
 852                 if (link->source->entity == source->entity &&
 853                     link->source->index == source->index &&
 854                     link->sink->entity == sink->entity &&
 855                     link->sink->index == sink->index)
 856                         return link;
 857         }
 858
 859         return NULL;
 860 }
 861 EXPORT_SYMBOL_GPL(media_entity_find_link);
 862
 863 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 864 {
 865         struct media_link *link;
 866
 867         list_for_each_entry(link, &pad->entity->links, list) {
 868                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 869                         continue;
 870
 871                 if (link->source == pad)
 872                         return link->sink;
 873
 874                 if (link->sink == pad)
 875                         return link->source;
 876         }
 877
 878         return NULL;
 879
 880 }
 881 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 882
 883 static void media_interface_init(struct media_device *mdev,
 884                                  struct media_interface *intf,
 885                                  u32 gobj_type,
 886                                  u32 intf_type, u32 flags)
 887 {
 888         intf->type = intf_type;
 889         intf->flags = flags;
 890         INIT_LIST_HEAD(&intf->links);
 891
 892         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 893 }
 894
 895 /* Functions related to the media interface via device nodes */
 896
 897 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 898                                                 u32 type, u32 flags,
 899                                                 u32 major, u32 minor)
 900 {
 901         struct media_intf_devnode *devnode;
 902
 903         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 904         if (!devnode)
 905                 return NULL;
 906
 907         devnode->major = major;
 908         devnode->minor = minor;
 909
 910         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 911                              type, flags);
 912
 913         return devnode;
 914 }
 915 EXPORT_SYMBOL_GPL(media_devnode_create);
 916
 917 void media_devnode_remove(struct media_intf_devnode *devnode)
 918 {
 919         media_remove_intf_links(&devnode->intf);
 920         media_gobj_destroy(&devnode->intf.graph_obj);
 921         kfree(devnode);
 922 }
 923 EXPORT_SYMBOL_GPL(media_devnode_remove);
 924
 925 struct media_link *media_create_intf_link(struct media_entity *entity,
 926                                             struct media_interface *intf,
 927                                             u32 flags)
 928 {
 929         struct media_link *link;
 930
 931         link = media_add_link(&intf->links);
 932         if (link == NULL)
 933                 return NULL;
 934
 935         link->intf = intf;
 936         link->entity = entity;
 937         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 938
 939         /* Initialize graph object embedded at the new link */
 940         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 941                         &link->graph_obj);
 942
 943         return link;
 944 }
 945 EXPORT_SYMBOL_GPL(media_create_intf_link);
 946
 947 void __media_remove_intf_link(struct media_link *link)
 948 {
 949         list_del(&link->list);
 950         media_gobj_destroy(&link->graph_obj);
 951         kfree(link);
 952 }
 953 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 954
 955 void media_remove_intf_link(struct media_link *link)
 956 {
 957         struct media_device *mdev = link->graph_obj.mdev;
 958
 959         /* Do nothing if the intf is not registered. */
 960         if (mdev == NULL)
 961                 return;
 962
 963         mutex_lock(&mdev->graph_mutex);
 964         __media_remove_intf_link(link);
 965         mutex_unlock(&mdev->graph_mutex);
 966 }
 967 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 968
 969 void __media_remove_intf_links(struct media_interface *intf)
 970 {
 971         struct media_link *link, *tmp;
 972
 973         list_for_each_entry_safe(link, tmp, &intf->links, list)
 974                 __media_remove_intf_link(link);
 975
 976 }
 977 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 978
 979 void media_remove_intf_links(struct media_interface *intf)
 980 {
 981         struct media_device *mdev = intf->graph_obj.mdev;
 982
 983         /* Do nothing if the intf is not registered. */
 984         if (mdev == NULL)
 985                 return;
 986
 987         mutex_lock(&mdev->graph_mutex);
 988         __media_remove_intf_links(intf);
 989         mutex_unlock(&mdev->graph_mutex);
 990 }
 991 EXPORT_SYMBOL_GPL(media_remove_intf_links);