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         gobj->mdev->topology_version++;
 209
 210         /* Remove the object from mdev list */
 211         list_del(&gobj->list);
 212 }
 213
 214 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 215                            struct media_pad *pads)
 216 {
 217         struct media_device *mdev = entity->graph_obj.mdev;
 218         unsigned int i;
 219
 220         entity->num_pads = num_pads;
 221         entity->pads = pads;
 222
 223         if (mdev)
 224                 mutex_lock(&mdev->graph_mutex);
 225
 226         for (i = 0; i < num_pads; i++) {
 227                 pads[i].entity = entity;
 228                 pads[i].index = i;
 229                 if (mdev)
 230                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 231                                         &entity->pads[i].graph_obj);
 232         }
 233
 234         if (mdev)
 235                 mutex_unlock(&mdev->graph_mutex);
 236
 237         return 0;
 238 }
 239 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 240
 241 /* -----------------------------------------------------------------------------
 242  * Graph traversal
 243  */
 244
 245 static struct media_entity *
 246 media_entity_other(struct media_entity *entity, struct media_link *link)
 247 {
 248         if (link->source->entity == entity)
 249                 return link->sink->entity;
 250         else
 251                 return link->source->entity;
 252 }
 253
 254 /* push an entity to traversal stack */
 255 static void stack_push(struct media_entity_graph *graph,
 256                        struct media_entity *entity)
 257 {
 258         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 259                 WARN_ON(1);
 260                 return;
 261         }
 262         graph->top++;
 263         graph->stack[graph->top].link = entity->links.next;
 264         graph->stack[graph->top].entity = entity;
 265 }
 266
 267 static struct media_entity *stack_pop(struct media_entity_graph *graph)
 268 {
 269         struct media_entity *entity;
 270
 271         entity = graph->stack[graph->top].entity;
 272         graph->top--;
 273
 274         return entity;
 275 }
 276
 277 #define link_top(en)    ((en)->stack[(en)->top].link)
 278 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 279
 280 /*
 281  * TODO: Get rid of this.
 282  */
 283 #define MEDIA_ENTITY_MAX_PADS           512
 284
 285 /**
 286  * media_entity_graph_walk_init - Allocate resources for graph walk
 287  * @graph: Media graph structure that will be used to walk the graph
 288  * @mdev: Media device
 289  *
 290  * Reserve resources for graph walk in media device's current
 291  * state. The memory must be released using
 292  * media_entity_graph_walk_free().
 293  *
 294  * Returns error on failure, zero on success.
 295  */
 296 __must_check int media_entity_graph_walk_init(
 297         struct media_entity_graph *graph, struct media_device *mdev)
 298 {
 299         return media_entity_enum_init(&graph->ent_enum, mdev);
 300 }
 301 EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
 302
 303 /**
 304  * media_entity_graph_walk_cleanup - Release resources related to graph walking
 305  * @graph: Media graph structure that was used to walk the graph
 306  */
 307 void media_entity_graph_walk_cleanup(struct media_entity_graph *graph)
 308 {
 309         media_entity_enum_cleanup(&graph->ent_enum);
 310 }
 311 EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
 312
 313 void media_entity_graph_walk_start(struct media_entity_graph *graph,
 314                                    struct media_entity *entity)
 315 {
 316         media_entity_enum_zero(&graph->ent_enum);
 317         media_entity_enum_set(&graph->ent_enum, entity);
 318
 319         graph->top = 0;
 320         graph->stack[graph->top].entity = NULL;
 321         stack_push(graph, entity);
 322 }
 323 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
 324
 325 struct media_entity *
 326 media_entity_graph_walk_next(struct media_entity_graph *graph)
 327 {
 328         if (stack_top(graph) == NULL)
 329                 return NULL;
 330
 331         /*
 332          * Depth first search. Push entity to stack and continue from
 333          * top of the stack until no more entities on the level can be
 334          * found.
 335          */
 336         while (link_top(graph) != &stack_top(graph)->links) {
 337                 struct media_entity *entity = stack_top(graph);
 338                 struct media_link *link;
 339                 struct media_entity *next;
 340
 341                 link = list_entry(link_top(graph), typeof(*link), list);
 342
 343                 /* The link is not enabled so we do not follow. */
 344                 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 345                         link_top(graph) = link_top(graph)->next;
 346                         continue;
 347                 }
 348
 349                 /* Get the entity in the other end of the link . */
 350                 next = media_entity_other(entity, link);
 351
 352                 /* Has the entity already been visited? */
 353                 if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 354                         link_top(graph) = link_top(graph)->next;
 355                         continue;
 356                 }
 357
 358                 /* Push the new entity to stack and start over. */
 359                 link_top(graph) = link_top(graph)->next;
 360                 stack_push(graph, next);
 361         }
 362
 363         return stack_pop(graph);
 364 }
 365 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
 366
 367 /* -----------------------------------------------------------------------------
 368  * Pipeline management
 369  */
 370
 371 __must_check int __media_entity_pipeline_start(struct media_entity *entity,
 372                                                struct media_pipeline *pipe)
 373 {
 374         struct media_device *mdev = entity->graph_obj.mdev;
 375         struct media_entity_graph *graph = &pipe->graph;
 376         struct media_entity *entity_err = entity;
 377         struct media_link *link;
 378         int ret;
 379
 380         if (!pipe->streaming_count++) {
 381                 ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 382                 if (ret)
 383                         goto error_graph_walk_start;
 384         }
 385
 386         media_entity_graph_walk_start(&pipe->graph, entity);
 387
 388         while ((entity = media_entity_graph_walk_next(graph))) {
 389                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 390                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 391
 392                 entity->stream_count++;
 393
 394                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 395                         ret = -EBUSY;
 396                         goto error;
 397                 }
 398
 399                 entity->pipe = pipe;
 400
 401                 /* Already streaming --- no need to check. */
 402                 if (entity->stream_count > 1)
 403                         continue;
 404
 405                 if (!entity->ops || !entity->ops->link_validate)
 406                         continue;
 407
 408                 bitmap_zero(active, entity->num_pads);
 409                 bitmap_fill(has_no_links, entity->num_pads);
 410
 411                 list_for_each_entry(link, &entity->links, list) {
 412                         struct media_pad *pad = link->sink->entity == entity
 413                                                 ? link->sink : link->source;
 414
 415                         /* Mark that a pad is connected by a link. */
 416                         bitmap_clear(has_no_links, pad->index, 1);
 417
 418                         /*
 419                          * Pads that either do not need to connect or
 420                          * are connected through an enabled link are
 421                          * fine.
 422                          */
 423                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 424                             link->flags & MEDIA_LNK_FL_ENABLED)
 425                                 bitmap_set(active, pad->index, 1);
 426
 427                         /*
 428                          * Link validation will only take place for
 429                          * sink ends of the link that are enabled.
 430                          */
 431                         if (link->sink != pad ||
 432                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 433                                 continue;
 434
 435                         ret = entity->ops->link_validate(link);
 436                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 437                                 dev_dbg(entity->graph_obj.mdev->dev,
 438                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 439                                         link->source->entity->name,
 440                                         link->source->index,
 441                                         entity->name, link->sink->index, ret);
 442                                 goto error;
 443                         }
 444                 }
 445
 446                 /* Either no links or validated links are fine. */
 447                 bitmap_or(active, active, has_no_links, entity->num_pads);
 448
 449                 if (!bitmap_full(active, entity->num_pads)) {
 450                         ret = -ENOLINK;
 451                         dev_dbg(entity->graph_obj.mdev->dev,
 452                                 "\"%s\":%u must be connected by an enabled link\n",
 453                                 entity->name,
 454                                 (unsigned)find_first_zero_bit(
 455                                         active, entity->num_pads));
 456                         goto error;
 457                 }
 458         }
 459
 460         return 0;
 461
 462 error:
 463         /*
 464          * Link validation on graph failed. We revert what we did and
 465          * return the error.
 466          */
 467         media_entity_graph_walk_start(graph, entity_err);
 468
 469         while ((entity_err = media_entity_graph_walk_next(graph))) {
 470                 /* don't let the stream_count go negative */
 471                 if (entity->stream_count > 0) {
 472                         entity_err->stream_count--;
 473                         if (entity_err->stream_count == 0)
 474                                 entity_err->pipe = NULL;
 475                 }
 476
 477                 /*
 478                  * We haven't increased stream_count further than this
 479                  * so we quit here.
 480                  */
 481                 if (entity_err == entity)
 482                         break;
 483         }
 484
 485 error_graph_walk_start:
 486         if (!--pipe->streaming_count)
 487                 media_entity_graph_walk_cleanup(graph);
 488
 489         return ret;
 490 }
 491 EXPORT_SYMBOL_GPL(__media_entity_pipeline_start);
 492
 493 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 494                                              struct media_pipeline *pipe)
 495 {
 496         struct media_device *mdev = entity->graph_obj.mdev;
 497         int ret;
 498
 499         mutex_lock(&mdev->graph_mutex);
 500         ret = __media_entity_pipeline_start(entity, pipe);
 501         mutex_unlock(&mdev->graph_mutex);
 502         return ret;
 503 }
 504 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 505
 506 void __media_entity_pipeline_stop(struct media_entity *entity)
 507 {
 508         struct media_entity_graph *graph = &entity->pipe->graph;
 509         struct media_pipeline *pipe = entity->pipe;
 510
 511
 512         WARN_ON(!pipe->streaming_count);
 513         media_entity_graph_walk_start(graph, entity);
 514
 515         while ((entity = media_entity_graph_walk_next(graph))) {
 516                 /* don't let the stream_count go negative */
 517                 if (entity->stream_count > 0) {
 518                         entity->stream_count--;
 519                         if (entity->stream_count == 0)
 520                                 entity->pipe = NULL;
 521                 }
 522         }
 523
 524         if (!--pipe->streaming_count)
 525                 media_entity_graph_walk_cleanup(graph);
 526
 527 }
 528 EXPORT_SYMBOL_GPL(__media_entity_pipeline_stop);
 529
 530 void media_entity_pipeline_stop(struct media_entity *entity)
 531 {
 532         struct media_device *mdev = entity->graph_obj.mdev;
 533
 534         mutex_lock(&mdev->graph_mutex);
 535         __media_entity_pipeline_stop(entity);
 536         mutex_unlock(&mdev->graph_mutex);
 537 }
 538 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
 539
 540 /* -----------------------------------------------------------------------------
 541  * Module use count
 542  */
 543
 544 struct media_entity *media_entity_get(struct media_entity *entity)
 545 {
 546         if (entity == NULL)
 547                 return NULL;
 548
 549         if (entity->graph_obj.mdev->dev &&
 550             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 551                 return NULL;
 552
 553         return entity;
 554 }
 555 EXPORT_SYMBOL_GPL(media_entity_get);
 556
 557 void media_entity_put(struct media_entity *entity)
 558 {
 559         if (entity == NULL)
 560                 return;
 561
 562         if (entity->graph_obj.mdev->dev)
 563                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 564 }
 565 EXPORT_SYMBOL_GPL(media_entity_put);
 566
 567 /* -----------------------------------------------------------------------------
 568  * Links management
 569  */
 570
 571 static struct media_link *media_add_link(struct list_head *head)
 572 {
 573         struct media_link *link;
 574
 575         link = kzalloc(sizeof(*link), GFP_KERNEL);
 576         if (link == NULL)
 577                 return NULL;
 578
 579         list_add_tail(&link->list, head);
 580
 581         return link;
 582 }
 583
 584 static void __media_entity_remove_link(struct media_entity *entity,
 585                                        struct media_link *link)
 586 {
 587         struct media_link *rlink, *tmp;
 588         struct media_entity *remote;
 589
 590         if (link->source->entity == entity)
 591                 remote = link->sink->entity;
 592         else
 593                 remote = link->source->entity;
 594
 595         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 596                 if (rlink != link->reverse)
 597                         continue;
 598
 599                 if (link->source->entity == entity)
 600                         remote->num_backlinks--;
 601
 602                 /* Remove the remote link */
 603                 list_del(&rlink->list);
 604                 media_gobj_destroy(&rlink->graph_obj);
 605                 kfree(rlink);
 606
 607                 if (--remote->num_links == 0)
 608                         break;
 609         }
 610         list_del(&link->list);
 611         media_gobj_destroy(&link->graph_obj);
 612         kfree(link);
 613 }
 614
 615 int
 616 media_create_pad_link(struct media_entity *source, u16 source_pad,
 617                          struct media_entity *sink, u16 sink_pad, u32 flags)
 618 {
 619         struct media_link *link;
 620         struct media_link *backlink;
 621
 622         BUG_ON(source == NULL || sink == NULL);
 623         BUG_ON(source_pad >= source->num_pads);
 624         BUG_ON(sink_pad >= sink->num_pads);
 625
 626         link = media_add_link(&source->links);
 627         if (link == NULL)
 628                 return -ENOMEM;
 629
 630         link->source = &source->pads[source_pad];
 631         link->sink = &sink->pads[sink_pad];
 632         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 633
 634         /* Initialize graph object embedded at the new link */
 635         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 636                         &link->graph_obj);
 637
 638         /* Create the backlink. Backlinks are used to help graph traversal and
 639          * are not reported to userspace.
 640          */
 641         backlink = media_add_link(&sink->links);
 642         if (backlink == NULL) {
 643                 __media_entity_remove_link(source, link);
 644                 return -ENOMEM;
 645         }
 646
 647         backlink->source = &source->pads[source_pad];
 648         backlink->sink = &sink->pads[sink_pad];
 649         backlink->flags = flags;
 650         backlink->is_backlink = true;
 651
 652         /* Initialize graph object embedded at the new link */
 653         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 654                         &backlink->graph_obj);
 655
 656         link->reverse = backlink;
 657         backlink->reverse = link;
 658
 659         sink->num_backlinks++;
 660         sink->num_links++;
 661         source->num_links++;
 662
 663         return 0;
 664 }
 665 EXPORT_SYMBOL_GPL(media_create_pad_link);
 666
 667 int media_create_pad_links(const struct media_device *mdev,
 668                            const u32 source_function,
 669                            struct media_entity *source,
 670                            const u16 source_pad,
 671                            const u32 sink_function,
 672                            struct media_entity *sink,
 673                            const u16 sink_pad,
 674                            u32 flags,
 675                            const bool allow_both_undefined)
 676 {
 677         struct media_entity *entity;
 678         unsigned function;
 679         int ret;
 680
 681         /* Trivial case: 1:1 relation */
 682         if (source && sink)
 683                 return media_create_pad_link(source, source_pad,
 684                                              sink, sink_pad, flags);
 685
 686         /* Worse case scenario: n:n relation */
 687         if (!source && !sink) {
 688                 if (!allow_both_undefined)
 689                         return 0;
 690                 media_device_for_each_entity(source, mdev) {
 691                         if (source->function != source_function)
 692                                 continue;
 693                         media_device_for_each_entity(sink, mdev) {
 694                                 if (sink->function != sink_function)
 695                                         continue;
 696                                 ret = media_create_pad_link(source, source_pad,
 697                                                             sink, sink_pad,
 698                                                             flags);
 699                                 if (ret)
 700                                         return ret;
 701                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 702                                            MEDIA_LNK_FL_IMMUTABLE);
 703                         }
 704                 }
 705                 return 0;
 706         }
 707
 708         /* Handle 1:n and n:1 cases */
 709         if (source)
 710                 function = sink_function;
 711         else
 712                 function = source_function;
 713
 714         media_device_for_each_entity(entity, mdev) {
 715                 if (entity->function != function)
 716                         continue;
 717
 718                 if (source)
 719                         ret = media_create_pad_link(source, source_pad,
 720                                                     entity, sink_pad, flags);
 721                 else
 722                         ret = media_create_pad_link(entity, source_pad,
 723                                                     sink, sink_pad, flags);
 724                 if (ret)
 725                         return ret;
 726                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 727         }
 728         return 0;
 729 }
 730 EXPORT_SYMBOL_GPL(media_create_pad_links);
 731
 732 void __media_entity_remove_links(struct media_entity *entity)
 733 {
 734         struct media_link *link, *tmp;
 735
 736         list_for_each_entry_safe(link, tmp, &entity->links, list)
 737                 __media_entity_remove_link(entity, link);
 738
 739         entity->num_links = 0;
 740         entity->num_backlinks = 0;
 741 }
 742 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 743
 744 void media_entity_remove_links(struct media_entity *entity)
 745 {
 746         struct media_device *mdev = entity->graph_obj.mdev;
 747
 748         /* Do nothing if the entity is not registered. */
 749         if (mdev == NULL)
 750                 return;
 751
 752         mutex_lock(&mdev->graph_mutex);
 753         __media_entity_remove_links(entity);
 754         mutex_unlock(&mdev->graph_mutex);
 755 }
 756 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 757
 758 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 759 {
 760         int ret;
 761
 762         /* Notify both entities. */
 763         ret = media_entity_call(link->source->entity, link_setup,
 764                                 link->source, link->sink, flags);
 765         if (ret < 0 && ret != -ENOIOCTLCMD)
 766                 return ret;
 767
 768         ret = media_entity_call(link->sink->entity, link_setup,
 769                                 link->sink, link->source, flags);
 770         if (ret < 0 && ret != -ENOIOCTLCMD) {
 771                 media_entity_call(link->source->entity, link_setup,
 772                                   link->source, link->sink, link->flags);
 773                 return ret;
 774         }
 775
 776         link->flags = flags;
 777         link->reverse->flags = link->flags;
 778
 779         return 0;
 780 }
 781
 782 int __media_entity_setup_link(struct media_link *link, u32 flags)
 783 {
 784         const u32 mask = MEDIA_LNK_FL_ENABLED;
 785         struct media_device *mdev;
 786         struct media_entity *source, *sink;
 787         int ret = -EBUSY;
 788
 789         if (link == NULL)
 790                 return -EINVAL;
 791
 792         /* The non-modifiable link flags must not be modified. */
 793         if ((link->flags & ~mask) != (flags & ~mask))
 794                 return -EINVAL;
 795
 796         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 797                 return link->flags == flags ? 0 : -EINVAL;
 798
 799         if (link->flags == flags)
 800                 return 0;
 801
 802         source = link->source->entity;
 803         sink = link->sink->entity;
 804
 805         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 806             (source->stream_count || sink->stream_count))
 807                 return -EBUSY;
 808
 809         mdev = source->graph_obj.mdev;
 810
 811         if (mdev->ops && mdev->ops->link_notify) {
 812                 ret = mdev->ops->link_notify(link, flags,
 813                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 814                 if (ret < 0)
 815                         return ret;
 816         }
 817
 818         ret = __media_entity_setup_link_notify(link, flags);
 819
 820         if (mdev->ops && mdev->ops->link_notify)
 821                 mdev->ops->link_notify(link, flags,
 822                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 823
 824         return ret;
 825 }
 826 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 827
 828 int media_entity_setup_link(struct media_link *link, u32 flags)
 829 {
 830         int ret;
 831
 832         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 833         ret = __media_entity_setup_link(link, flags);
 834         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 835
 836         return ret;
 837 }
 838 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 839
 840 struct media_link *
 841 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 842 {
 843         struct media_link *link;
 844
 845         list_for_each_entry(link, &source->entity->links, list) {
 846                 if (link->source->entity == source->entity &&
 847                     link->source->index == source->index &&
 848                     link->sink->entity == sink->entity &&
 849                     link->sink->index == sink->index)
 850                         return link;
 851         }
 852
 853         return NULL;
 854 }
 855 EXPORT_SYMBOL_GPL(media_entity_find_link);
 856
 857 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 858 {
 859         struct media_link *link;
 860
 861         list_for_each_entry(link, &pad->entity->links, list) {
 862                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 863                         continue;
 864
 865                 if (link->source == pad)
 866                         return link->sink;
 867
 868                 if (link->sink == pad)
 869                         return link->source;
 870         }
 871
 872         return NULL;
 873
 874 }
 875 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 876
 877 static void media_interface_init(struct media_device *mdev,
 878                                  struct media_interface *intf,
 879                                  u32 gobj_type,
 880                                  u32 intf_type, u32 flags)
 881 {
 882         intf->type = intf_type;
 883         intf->flags = flags;
 884         INIT_LIST_HEAD(&intf->links);
 885
 886         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 887 }
 888
 889 /* Functions related to the media interface via device nodes */
 890
 891 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 892                                                 u32 type, u32 flags,
 893                                                 u32 major, u32 minor)
 894 {
 895         struct media_intf_devnode *devnode;
 896
 897         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 898         if (!devnode)
 899                 return NULL;
 900
 901         devnode->major = major;
 902         devnode->minor = minor;
 903
 904         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 905                              type, flags);
 906
 907         return devnode;
 908 }
 909 EXPORT_SYMBOL_GPL(media_devnode_create);
 910
 911 void media_devnode_remove(struct media_intf_devnode *devnode)
 912 {
 913         media_remove_intf_links(&devnode->intf);
 914         media_gobj_destroy(&devnode->intf.graph_obj);
 915         kfree(devnode);
 916 }
 917 EXPORT_SYMBOL_GPL(media_devnode_remove);
 918
 919 struct media_link *media_create_intf_link(struct media_entity *entity,
 920                                             struct media_interface *intf,
 921                                             u32 flags)
 922 {
 923         struct media_link *link;
 924
 925         link = media_add_link(&intf->links);
 926         if (link == NULL)
 927                 return NULL;
 928
 929         link->intf = intf;
 930         link->entity = entity;
 931         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 932
 933         /* Initialize graph object embedded at the new link */
 934         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 935                         &link->graph_obj);
 936
 937         return link;
 938 }
 939 EXPORT_SYMBOL_GPL(media_create_intf_link);
 940
 941 void __media_remove_intf_link(struct media_link *link)
 942 {
 943         list_del(&link->list);
 944         media_gobj_destroy(&link->graph_obj);
 945         kfree(link);
 946 }
 947 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 948
 949 void media_remove_intf_link(struct media_link *link)
 950 {
 951         struct media_device *mdev = link->graph_obj.mdev;
 952
 953         /* Do nothing if the intf is not registered. */
 954         if (mdev == NULL)
 955                 return;
 956
 957         mutex_lock(&mdev->graph_mutex);
 958         __media_remove_intf_link(link);
 959         mutex_unlock(&mdev->graph_mutex);
 960 }
 961 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 962
 963 void __media_remove_intf_links(struct media_interface *intf)
 964 {
 965         struct media_link *link, *tmp;
 966
 967         list_for_each_entry_safe(link, tmp, &intf->links, list)
 968                 __media_remove_intf_link(link);
 969
 970 }
 971 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 972
 973 void media_remove_intf_links(struct media_interface *intf)
 974 {
 975         struct media_device *mdev = intf->graph_obj.mdev;
 976
 977         /* Do nothing if the intf is not registered. */
 978         if (mdev == NULL)
 979                 return;
 980
 981         mutex_lock(&mdev->graph_mutex);
 982         __media_remove_intf_links(intf);
 983         mutex_unlock(&mdev->graph_mutex);
 984 }
 985 EXPORT_SYMBOL_GPL(media_remove_intf_links);