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 "frontend";
  50         case MEDIA_INTF_T_DVB_DEMUX:
  51                 return "demux";
  52         case MEDIA_INTF_T_DVB_DVR:
  53                 return "DVR";
  54         case MEDIA_INTF_T_DVB_CA:
  55                 return  "CA";
  56         case MEDIA_INTF_T_DVB_NET:
  57                 return "dvbnet";
  58         case MEDIA_INTF_T_V4L_VIDEO:
  59                 return "video";
  60         case MEDIA_INTF_T_V4L_VBI:
  61                 return "vbi";
  62         case MEDIA_INTF_T_V4L_RADIO:
  63                 return "radio";
  64         case MEDIA_INTF_T_V4L_SUBDEV:
  65                 return "v4l2-subdev";
  66         case MEDIA_INTF_T_V4L_SWRADIO:
  67                 return "swradio";
  68         default:
  69                 return "unknown-intf";
  70         }
  71 };
  72
  73 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  74                                           int idx_max)
  75 {
  76         ent_enum->bmap = kcalloc(DIV_ROUND_UP(idx_max, BITS_PER_LONG),
  77                                  sizeof(long), GFP_KERNEL);
  78         if (!ent_enum->bmap)
  79                 return -ENOMEM;
  80
  81         bitmap_zero(ent_enum->bmap, idx_max);
  82         ent_enum->idx_max = idx_max;
  83
  84         return 0;
  85 }
  86 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
  87
  88 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
  89 {
  90         kfree(ent_enum->bmap);
  91 }
  92 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
  93
  94 /**
  95  *  dev_dbg_obj - Prints in debug mode a change on some object
  96  *
  97  * @event_name: Name of the event to report. Could be __func__
  98  * @gobj:       Pointer to the object
  99  *
 100  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 101  * won't produce any code.
 102  */
 103 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 104 {
 105 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 106         switch (media_type(gobj)) {
 107         case MEDIA_GRAPH_ENTITY:
 108                 dev_dbg(gobj->mdev->dev,
 109                         "%s: id 0x%08x entity#%d: '%s'\n",
 110                         event_name, gobj->id, media_localid(gobj),
 111                         gobj_to_entity(gobj)->name);
 112                 break;
 113         case MEDIA_GRAPH_LINK:
 114         {
 115                 struct media_link *link = gobj_to_link(gobj);
 116
 117                 dev_dbg(gobj->mdev->dev,
 118                         "%s: id 0x%08x link#%d: %s#%d ==> %s#%d\n",
 119                         event_name, gobj->id, media_localid(gobj),
 120
 121                         gobj_type(media_type(link->gobj0)),
 122                         media_localid(link->gobj0),
 123
 124                         gobj_type(media_type(link->gobj1)),
 125                         media_localid(link->gobj1));
 126                 break;
 127         }
 128         case MEDIA_GRAPH_PAD:
 129         {
 130                 struct media_pad *pad = gobj_to_pad(gobj);
 131
 132                 dev_dbg(gobj->mdev->dev,
 133                         "%s: id 0x%08x %s%spad#%d: '%s':%d\n",
 134                         event_name, gobj->id,
 135                         pad->flags & MEDIA_PAD_FL_SINK   ? "  sink " : "",
 136                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 137                         media_localid(gobj),
 138                         pad->entity->name, pad->index);
 139                 break;
 140         }
 141         case MEDIA_GRAPH_INTF_DEVNODE:
 142         {
 143                 struct media_interface *intf = gobj_to_intf(gobj);
 144                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 145
 146                 dev_dbg(gobj->mdev->dev,
 147                         "%s: id 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
 148                         event_name, gobj->id, media_localid(gobj),
 149                         intf_type(intf),
 150                         devnode->major, devnode->minor);
 151                 break;
 152         }
 153         }
 154 #endif
 155 }
 156
 157 void media_gobj_create(struct media_device *mdev,
 158                            enum media_gobj_type type,
 159                            struct media_gobj *gobj)
 160 {
 161         BUG_ON(!mdev);
 162
 163         gobj->mdev = mdev;
 164
 165         /* Create a per-type unique object ID */
 166         switch (type) {
 167         case MEDIA_GRAPH_ENTITY:
 168                 gobj->id = media_gobj_gen_id(type, ++mdev->entity_id);
 169                 list_add_tail(&gobj->list, &mdev->entities);
 170                 break;
 171         case MEDIA_GRAPH_PAD:
 172                 gobj->id = media_gobj_gen_id(type, ++mdev->pad_id);
 173                 list_add_tail(&gobj->list, &mdev->pads);
 174                 break;
 175         case MEDIA_GRAPH_LINK:
 176                 gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
 177                 list_add_tail(&gobj->list, &mdev->links);
 178                 break;
 179         case MEDIA_GRAPH_INTF_DEVNODE:
 180                 gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
 181                 list_add_tail(&gobj->list, &mdev->interfaces);
 182                 break;
 183         }
 184
 185         mdev->topology_version++;
 186
 187         dev_dbg_obj(__func__, gobj);
 188 }
 189
 190 void media_gobj_destroy(struct media_gobj *gobj)
 191 {
 192         dev_dbg_obj(__func__, gobj);
 193
 194         gobj->mdev->topology_version++;
 195
 196         /* Remove the object from mdev list */
 197         list_del(&gobj->list);
 198 }
 199
 200 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 201                            struct media_pad *pads)
 202 {
 203         struct media_device *mdev = entity->graph_obj.mdev;
 204         unsigned int i;
 205
 206         entity->num_pads = num_pads;
 207         entity->pads = pads;
 208
 209         if (mdev)
 210                 spin_lock(&mdev->lock);
 211
 212         for (i = 0; i < num_pads; i++) {
 213                 pads[i].entity = entity;
 214                 pads[i].index = i;
 215                 if (mdev)
 216                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 217                                         &entity->pads[i].graph_obj);
 218         }
 219
 220         if (mdev)
 221                 spin_unlock(&mdev->lock);
 222
 223         return 0;
 224 }
 225 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 226
 227 /* -----------------------------------------------------------------------------
 228  * Graph traversal
 229  */
 230
 231 static struct media_entity *
 232 media_entity_other(struct media_entity *entity, struct media_link *link)
 233 {
 234         if (link->source->entity == entity)
 235                 return link->sink->entity;
 236         else
 237                 return link->source->entity;
 238 }
 239
 240 /* push an entity to traversal stack */
 241 static void stack_push(struct media_entity_graph *graph,
 242                        struct media_entity *entity)
 243 {
 244         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 245                 WARN_ON(1);
 246                 return;
 247         }
 248         graph->top++;
 249         graph->stack[graph->top].link = entity->links.next;
 250         graph->stack[graph->top].entity = entity;
 251 }
 252
 253 static struct media_entity *stack_pop(struct media_entity_graph *graph)
 254 {
 255         struct media_entity *entity;
 256
 257         entity = graph->stack[graph->top].entity;
 258         graph->top--;
 259
 260         return entity;
 261 }
 262
 263 #define link_top(en)    ((en)->stack[(en)->top].link)
 264 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 265
 266 /*
 267  * TODO: Get rid of this.
 268  */
 269 #define MEDIA_ENTITY_MAX_PADS           63
 270
 271 /**
 272  * media_entity_graph_walk_init - Allocate resources for graph walk
 273  * @graph: Media graph structure that will be used to walk the graph
 274  * @mdev: Media device
 275  *
 276  * Reserve resources for graph walk in media device's current
 277  * state. The memory must be released using
 278  * media_entity_graph_walk_free().
 279  *
 280  * Returns error on failure, zero on success.
 281  */
 282 __must_check int media_entity_graph_walk_init(
 283         struct media_entity_graph *graph, struct media_device *mdev)
 284 {
 285         return media_entity_enum_init(&graph->ent_enum, mdev);
 286 }
 287 EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
 288
 289 /**
 290  * media_entity_graph_walk_cleanup - Release resources related to graph walking
 291  * @graph: Media graph structure that was used to walk the graph
 292  */
 293 void media_entity_graph_walk_cleanup(struct media_entity_graph *graph)
 294 {
 295         media_entity_enum_cleanup(&graph->ent_enum);
 296 }
 297 EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
 298
 299 void media_entity_graph_walk_start(struct media_entity_graph *graph,
 300                                    struct media_entity *entity)
 301 {
 302         media_entity_enum_zero(&graph->ent_enum);
 303         media_entity_enum_set(&graph->ent_enum, entity);
 304
 305         graph->top = 0;
 306         graph->stack[graph->top].entity = NULL;
 307         stack_push(graph, entity);
 308 }
 309 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
 310
 311 struct media_entity *
 312 media_entity_graph_walk_next(struct media_entity_graph *graph)
 313 {
 314         if (stack_top(graph) == NULL)
 315                 return NULL;
 316
 317         /*
 318          * Depth first search. Push entity to stack and continue from
 319          * top of the stack until no more entities on the level can be
 320          * found.
 321          */
 322         while (link_top(graph) != &stack_top(graph)->links) {
 323                 struct media_entity *entity = stack_top(graph);
 324                 struct media_link *link;
 325                 struct media_entity *next;
 326
 327                 link = list_entry(link_top(graph), typeof(*link), list);
 328
 329                 /* The link is not enabled so we do not follow. */
 330                 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 331                         link_top(graph) = link_top(graph)->next;
 332                         continue;
 333                 }
 334
 335                 /* Get the entity in the other end of the link . */
 336                 next = media_entity_other(entity, link);
 337
 338                 /* Has the entity already been visited? */
 339                 if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 340                         link_top(graph) = link_top(graph)->next;
 341                         continue;
 342                 }
 343
 344                 /* Push the new entity to stack and start over. */
 345                 link_top(graph) = link_top(graph)->next;
 346                 stack_push(graph, next);
 347         }
 348
 349         return stack_pop(graph);
 350 }
 351 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
 352
 353 /* -----------------------------------------------------------------------------
 354  * Pipeline management
 355  */
 356
 357 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 358                                              struct media_pipeline *pipe)
 359 {
 360         struct media_device *mdev = entity->graph_obj.mdev;
 361         struct media_entity_graph *graph = &pipe->graph;
 362         struct media_entity *entity_err = entity;
 363         struct media_link *link;
 364         int ret;
 365
 366         mutex_lock(&mdev->graph_mutex);
 367
 368         if (!pipe->streaming_count++) {
 369                 ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 370                 if (ret)
 371                         goto error_graph_walk_start;
 372         }
 373
 374         media_entity_graph_walk_start(&pipe->graph, entity);
 375
 376         while ((entity = media_entity_graph_walk_next(graph))) {
 377                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 378                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 379
 380                 entity->stream_count++;
 381
 382                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 383                         ret = -EBUSY;
 384                         goto error;
 385                 }
 386
 387                 entity->pipe = pipe;
 388
 389                 /* Already streaming --- no need to check. */
 390                 if (entity->stream_count > 1)
 391                         continue;
 392
 393                 if (!entity->ops || !entity->ops->link_validate)
 394                         continue;
 395
 396                 bitmap_zero(active, entity->num_pads);
 397                 bitmap_fill(has_no_links, entity->num_pads);
 398
 399                 list_for_each_entry(link, &entity->links, list) {
 400                         struct media_pad *pad = link->sink->entity == entity
 401                                                 ? link->sink : link->source;
 402
 403                         /* Mark that a pad is connected by a link. */
 404                         bitmap_clear(has_no_links, pad->index, 1);
 405
 406                         /*
 407                          * Pads that either do not need to connect or
 408                          * are connected through an enabled link are
 409                          * fine.
 410                          */
 411                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 412                             link->flags & MEDIA_LNK_FL_ENABLED)
 413                                 bitmap_set(active, pad->index, 1);
 414
 415                         /*
 416                          * Link validation will only take place for
 417                          * sink ends of the link that are enabled.
 418                          */
 419                         if (link->sink != pad ||
 420                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 421                                 continue;
 422
 423                         ret = entity->ops->link_validate(link);
 424                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 425                                 dev_dbg(entity->graph_obj.mdev->dev,
 426                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 427                                         link->source->entity->name,
 428                                         link->source->index,
 429                                         entity->name, link->sink->index, ret);
 430                                 goto error;
 431                         }
 432                 }
 433
 434                 /* Either no links or validated links are fine. */
 435                 bitmap_or(active, active, has_no_links, entity->num_pads);
 436
 437                 if (!bitmap_full(active, entity->num_pads)) {
 438                         ret = -EPIPE;
 439                         dev_dbg(entity->graph_obj.mdev->dev,
 440                                 "\"%s\":%u must be connected by an enabled link\n",
 441                                 entity->name,
 442                                 (unsigned)find_first_zero_bit(
 443                                         active, entity->num_pads));
 444                         goto error;
 445                 }
 446         }
 447
 448         mutex_unlock(&mdev->graph_mutex);
 449
 450         return 0;
 451
 452 error:
 453         /*
 454          * Link validation on graph failed. We revert what we did and
 455          * return the error.
 456          */
 457         media_entity_graph_walk_start(graph, entity_err);
 458
 459         while ((entity_err = media_entity_graph_walk_next(graph))) {
 460                 entity_err->stream_count--;
 461                 if (entity_err->stream_count == 0)
 462                         entity_err->pipe = NULL;
 463
 464                 /*
 465                  * We haven't increased stream_count further than this
 466                  * so we quit here.
 467                  */
 468                 if (entity_err == entity)
 469                         break;
 470         }
 471
 472 error_graph_walk_start:
 473         if (!--pipe->streaming_count)
 474                 media_entity_graph_walk_cleanup(graph);
 475
 476         mutex_unlock(&mdev->graph_mutex);
 477
 478         return ret;
 479 }
 480 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 481
 482 void media_entity_pipeline_stop(struct media_entity *entity)
 483 {
 484         struct media_device *mdev = entity->graph_obj.mdev;
 485         struct media_entity_graph *graph = &entity->pipe->graph;
 486         struct media_pipeline *pipe = entity->pipe;
 487
 488         mutex_lock(&mdev->graph_mutex);
 489
 490         WARN_ON(!pipe->streaming_count);
 491         media_entity_graph_walk_start(graph, entity);
 492
 493         while ((entity = media_entity_graph_walk_next(graph))) {
 494                 entity->stream_count--;
 495                 if (entity->stream_count == 0)
 496                         entity->pipe = NULL;
 497         }
 498
 499         if (!--pipe->streaming_count)
 500                 media_entity_graph_walk_cleanup(graph);
 501
 502         mutex_unlock(&mdev->graph_mutex);
 503 }
 504 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
 505
 506 /* -----------------------------------------------------------------------------
 507  * Module use count
 508  */
 509
 510 struct media_entity *media_entity_get(struct media_entity *entity)
 511 {
 512         if (entity == NULL)
 513                 return NULL;
 514
 515         if (entity->graph_obj.mdev->dev &&
 516             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 517                 return NULL;
 518
 519         return entity;
 520 }
 521 EXPORT_SYMBOL_GPL(media_entity_get);
 522
 523 void media_entity_put(struct media_entity *entity)
 524 {
 525         if (entity == NULL)
 526                 return;
 527
 528         if (entity->graph_obj.mdev->dev)
 529                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 530 }
 531 EXPORT_SYMBOL_GPL(media_entity_put);
 532
 533 /* -----------------------------------------------------------------------------
 534  * Links management
 535  */
 536
 537 static struct media_link *media_add_link(struct list_head *head)
 538 {
 539         struct media_link *link;
 540
 541         link = kzalloc(sizeof(*link), GFP_KERNEL);
 542         if (link == NULL)
 543                 return NULL;
 544
 545         list_add_tail(&link->list, head);
 546
 547         return link;
 548 }
 549
 550 static void __media_entity_remove_link(struct media_entity *entity,
 551                                        struct media_link *link)
 552 {
 553         struct media_link *rlink, *tmp;
 554         struct media_entity *remote;
 555
 556         if (link->source->entity == entity)
 557                 remote = link->sink->entity;
 558         else
 559                 remote = link->source->entity;
 560
 561         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 562                 if (rlink != link->reverse)
 563                         continue;
 564
 565                 if (link->source->entity == entity)
 566                         remote->num_backlinks--;
 567
 568                 /* Remove the remote link */
 569                 list_del(&rlink->list);
 570                 media_gobj_destroy(&rlink->graph_obj);
 571                 kfree(rlink);
 572
 573                 if (--remote->num_links == 0)
 574                         break;
 575         }
 576         list_del(&link->list);
 577         media_gobj_destroy(&link->graph_obj);
 578         kfree(link);
 579 }
 580
 581 int
 582 media_create_pad_link(struct media_entity *source, u16 source_pad,
 583                          struct media_entity *sink, u16 sink_pad, u32 flags)
 584 {
 585         struct media_link *link;
 586         struct media_link *backlink;
 587
 588         BUG_ON(source == NULL || sink == NULL);
 589         BUG_ON(source_pad >= source->num_pads);
 590         BUG_ON(sink_pad >= sink->num_pads);
 591
 592         link = media_add_link(&source->links);
 593         if (link == NULL)
 594                 return -ENOMEM;
 595
 596         link->source = &source->pads[source_pad];
 597         link->sink = &sink->pads[sink_pad];
 598         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 599
 600         /* Initialize graph object embedded at the new link */
 601         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 602                         &link->graph_obj);
 603
 604         /* Create the backlink. Backlinks are used to help graph traversal and
 605          * are not reported to userspace.
 606          */
 607         backlink = media_add_link(&sink->links);
 608         if (backlink == NULL) {
 609                 __media_entity_remove_link(source, link);
 610                 return -ENOMEM;
 611         }
 612
 613         backlink->source = &source->pads[source_pad];
 614         backlink->sink = &sink->pads[sink_pad];
 615         backlink->flags = flags;
 616         backlink->is_backlink = true;
 617
 618         /* Initialize graph object embedded at the new link */
 619         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 620                         &backlink->graph_obj);
 621
 622         link->reverse = backlink;
 623         backlink->reverse = link;
 624
 625         sink->num_backlinks++;
 626         sink->num_links++;
 627         source->num_links++;
 628
 629         return 0;
 630 }
 631 EXPORT_SYMBOL_GPL(media_create_pad_link);
 632
 633 void __media_entity_remove_links(struct media_entity *entity)
 634 {
 635         struct media_link *link, *tmp;
 636
 637         list_for_each_entry_safe(link, tmp, &entity->links, list)
 638                 __media_entity_remove_link(entity, link);
 639
 640         entity->num_links = 0;
 641         entity->num_backlinks = 0;
 642 }
 643 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 644
 645 void media_entity_remove_links(struct media_entity *entity)
 646 {
 647         struct media_device *mdev = entity->graph_obj.mdev;
 648
 649         /* Do nothing if the entity is not registered. */
 650         if (mdev == NULL)
 651                 return;
 652
 653         spin_lock(&mdev->lock);
 654         __media_entity_remove_links(entity);
 655         spin_unlock(&mdev->lock);
 656 }
 657 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 658
 659 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 660 {
 661         int ret;
 662
 663         /* Notify both entities. */
 664         ret = media_entity_call(link->source->entity, link_setup,
 665                                 link->source, link->sink, flags);
 666         if (ret < 0 && ret != -ENOIOCTLCMD)
 667                 return ret;
 668
 669         ret = media_entity_call(link->sink->entity, link_setup,
 670                                 link->sink, link->source, flags);
 671         if (ret < 0 && ret != -ENOIOCTLCMD) {
 672                 media_entity_call(link->source->entity, link_setup,
 673                                   link->source, link->sink, link->flags);
 674                 return ret;
 675         }
 676
 677         link->flags = flags;
 678         link->reverse->flags = link->flags;
 679
 680         return 0;
 681 }
 682
 683 int __media_entity_setup_link(struct media_link *link, u32 flags)
 684 {
 685         const u32 mask = MEDIA_LNK_FL_ENABLED;
 686         struct media_device *mdev;
 687         struct media_entity *source, *sink;
 688         int ret = -EBUSY;
 689
 690         if (link == NULL)
 691                 return -EINVAL;
 692
 693         /* The non-modifiable link flags must not be modified. */
 694         if ((link->flags & ~mask) != (flags & ~mask))
 695                 return -EINVAL;
 696
 697         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 698                 return link->flags == flags ? 0 : -EINVAL;
 699
 700         if (link->flags == flags)
 701                 return 0;
 702
 703         source = link->source->entity;
 704         sink = link->sink->entity;
 705
 706         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 707             (source->stream_count || sink->stream_count))
 708                 return -EBUSY;
 709
 710         mdev = source->graph_obj.mdev;
 711
 712         if (mdev->link_notify) {
 713                 ret = mdev->link_notify(link, flags,
 714                                         MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 715                 if (ret < 0)
 716                         return ret;
 717         }
 718
 719         ret = __media_entity_setup_link_notify(link, flags);
 720
 721         if (mdev->link_notify)
 722                 mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);
 723
 724         return ret;
 725 }
 726
 727 int media_entity_setup_link(struct media_link *link, u32 flags)
 728 {
 729         int ret;
 730
 731         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 732         ret = __media_entity_setup_link(link, flags);
 733         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 734
 735         return ret;
 736 }
 737 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 738
 739 struct media_link *
 740 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 741 {
 742         struct media_link *link;
 743
 744         list_for_each_entry(link, &source->entity->links, list) {
 745                 if (link->source->entity == source->entity &&
 746                     link->source->index == source->index &&
 747                     link->sink->entity == sink->entity &&
 748                     link->sink->index == sink->index)
 749                         return link;
 750         }
 751
 752         return NULL;
 753 }
 754 EXPORT_SYMBOL_GPL(media_entity_find_link);
 755
 756 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 757 {
 758         struct media_link *link;
 759
 760         list_for_each_entry(link, &pad->entity->links, list) {
 761                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 762                         continue;
 763
 764                 if (link->source == pad)
 765                         return link->sink;
 766
 767                 if (link->sink == pad)
 768                         return link->source;
 769         }
 770
 771         return NULL;
 772
 773 }
 774 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 775
 776 static void media_interface_init(struct media_device *mdev,
 777                                  struct media_interface *intf,
 778                                  u32 gobj_type,
 779                                  u32 intf_type, u32 flags)
 780 {
 781         intf->type = intf_type;
 782         intf->flags = flags;
 783         INIT_LIST_HEAD(&intf->links);
 784
 785         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 786 }
 787
 788 /* Functions related to the media interface via device nodes */
 789
 790 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 791                                                 u32 type, u32 flags,
 792                                                 u32 major, u32 minor)
 793 {
 794         struct media_intf_devnode *devnode;
 795
 796         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 797         if (!devnode)
 798                 return NULL;
 799
 800         devnode->major = major;
 801         devnode->minor = minor;
 802
 803         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 804                              type, flags);
 805
 806         return devnode;
 807 }
 808 EXPORT_SYMBOL_GPL(media_devnode_create);
 809
 810 void media_devnode_remove(struct media_intf_devnode *devnode)
 811 {
 812         media_remove_intf_links(&devnode->intf);
 813         media_gobj_destroy(&devnode->intf.graph_obj);
 814         kfree(devnode);
 815 }
 816 EXPORT_SYMBOL_GPL(media_devnode_remove);
 817
 818 struct media_link *media_create_intf_link(struct media_entity *entity,
 819                                             struct media_interface *intf,
 820                                             u32 flags)
 821 {
 822         struct media_link *link;
 823
 824         link = media_add_link(&intf->links);
 825         if (link == NULL)
 826                 return NULL;
 827
 828         link->intf = intf;
 829         link->entity = entity;
 830         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 831
 832         /* Initialize graph object embedded at the new link */
 833         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 834                         &link->graph_obj);
 835
 836         return link;
 837 }
 838 EXPORT_SYMBOL_GPL(media_create_intf_link);
 839
 840 void __media_remove_intf_link(struct media_link *link)
 841 {
 842         list_del(&link->list);
 843         media_gobj_destroy(&link->graph_obj);
 844         kfree(link);
 845 }
 846 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 847
 848 void media_remove_intf_link(struct media_link *link)
 849 {
 850         struct media_device *mdev = link->graph_obj.mdev;
 851
 852         /* Do nothing if the intf is not registered. */
 853         if (mdev == NULL)
 854                 return;
 855
 856         spin_lock(&mdev->lock);
 857         __media_remove_intf_link(link);
 858         spin_unlock(&mdev->lock);
 859 }
 860 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 861
 862 void __media_remove_intf_links(struct media_interface *intf)
 863 {
 864         struct media_link *link, *tmp;
 865
 866         list_for_each_entry_safe(link, tmp, &intf->links, list)
 867                 __media_remove_intf_link(link);
 868
 869 }
 870 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 871
 872 void media_remove_intf_links(struct media_interface *intf)
 873 {
 874         struct media_device *mdev = intf->graph_obj.mdev;
 875
 876         /* Do nothing if the intf is not registered. */
 877         if (mdev == NULL)
 878                 return;
 879
 880         spin_lock(&mdev->lock);
 881         __media_remove_intf_links(intf);
 882         spin_unlock(&mdev->lock);
 883 }
 884 EXPORT_SYMBOL_GPL(media_remove_intf_links);