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