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 /**
  30  *  dev_dbg_obj - Prints in debug mode a change on some object
  31  *
  32  * @event_name: Name of the event to report. Could be __func__
  33  * @gobj:       Pointer to the object
  34  *
  35  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
  36  * won't produce any code.
  37  */
  38 static inline const char *gobj_type(enum media_gobj_type type)
  39 {
  40         switch (type) {
  41         case MEDIA_GRAPH_ENTITY:
  42                 return "entity";
  43         case MEDIA_GRAPH_PAD:
  44                 return "pad";
  45         case MEDIA_GRAPH_LINK:
  46                 return "link";
  47         case MEDIA_GRAPH_INTF_DEVNODE:
  48                 return "intf-devnode";
  49         default:
  50                 return "unknown";
  51         }
  52 }
  53
  54 static inline const char *intf_type(struct media_interface *intf)
  55 {
  56         switch (intf->type) {
  57         case MEDIA_INTF_T_DVB_FE:
  58                 return "frontend";
  59         case MEDIA_INTF_T_DVB_DEMUX:
  60                 return "demux";
  61         case MEDIA_INTF_T_DVB_DVR:
  62                 return "DVR";
  63         case MEDIA_INTF_T_DVB_CA:
  64                 return  "CA";
  65         case MEDIA_INTF_T_DVB_NET:
  66                 return "dvbnet";
  67         case MEDIA_INTF_T_V4L_VIDEO:
  68                 return "video";
  69         case MEDIA_INTF_T_V4L_VBI:
  70                 return "vbi";
  71         case MEDIA_INTF_T_V4L_RADIO:
  72                 return "radio";
  73         case MEDIA_INTF_T_V4L_SUBDEV:
  74                 return "v4l2-subdev";
  75         case MEDIA_INTF_T_V4L_SWRADIO:
  76                 return "swradio";
  77         default:
  78                 return "unknown-intf";
  79         }
  80 };
  81
  82 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
  83 {
  84 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
  85         switch (media_type(gobj)) {
  86         case MEDIA_GRAPH_ENTITY:
  87                 dev_dbg(gobj->mdev->dev,
  88                         "%s: id 0x%08x entity#%d: '%s'\n",
  89                         event_name, gobj->id, media_localid(gobj),
  90                         gobj_to_entity(gobj)->name);
  91                 break;
  92         case MEDIA_GRAPH_LINK:
  93         {
  94                 struct media_link *link = gobj_to_link(gobj);
  95
  96                 dev_dbg(gobj->mdev->dev,
  97                         "%s: id 0x%08x link#%d: %s#%d ==> %s#%d\n",
  98                         event_name, gobj->id, media_localid(gobj),
  99
 100                         gobj_type(media_type(link->gobj0)),
 101                         media_localid(link->gobj0),
 102
 103                         gobj_type(media_type(link->gobj1)),
 104                         media_localid(link->gobj1));
 105                 break;
 106         }
 107         case MEDIA_GRAPH_PAD:
 108         {
 109                 struct media_pad *pad = gobj_to_pad(gobj);
 110
 111                 dev_dbg(gobj->mdev->dev,
 112                         "%s: id 0x%08x pad#%d: '%s':%d\n",
 113                         event_name, gobj->id, media_localid(gobj),
 114                         pad->entity->name, pad->index);
 115                 break;
 116         }
 117         case MEDIA_GRAPH_INTF_DEVNODE:
 118         {
 119                 struct media_interface *intf = gobj_to_intf(gobj);
 120                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 121
 122                 dev_dbg(gobj->mdev->dev,
 123                         "%s: id 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
 124                         event_name, gobj->id, media_localid(gobj),
 125                         intf_type(intf),
 126                         devnode->major, devnode->minor);
 127                 break;
 128         }
 129         }
 130 #endif
 131 }
 132
 133 /**
 134  *  media_gobj_init - Initialize a graph object
 135  *
 136  * @mdev:       Pointer to the media_device that contains the object
 137  * @type:       Type of the object
 138  * @gobj:       Pointer to the object
 139  *
 140  * This routine initializes the embedded struct media_gobj inside a
 141  * media graph object. It is called automatically if media_*_create()
 142  * calls are used. However, if the object (entity, link, pad, interface)
 143  * is embedded on some other object, this function should be called before
 144  * registering the object at the media controller.
 145  */
 146 void media_gobj_init(struct media_device *mdev,
 147                            enum media_gobj_type type,
 148                            struct media_gobj *gobj)
 149 {
 150         BUG_ON(!mdev);
 151
 152         gobj->mdev = mdev;
 153
 154         /* Create a per-type unique object ID */
 155         switch (type) {
 156         case MEDIA_GRAPH_ENTITY:
 157                 gobj->id = media_gobj_gen_id(type, ++mdev->entity_id);
 158                 break;
 159         case MEDIA_GRAPH_PAD:
 160                 gobj->id = media_gobj_gen_id(type, ++mdev->pad_id);
 161                 break;
 162         case MEDIA_GRAPH_LINK:
 163                 gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
 164                 break;
 165         case MEDIA_GRAPH_INTF_DEVNODE:
 166                 gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
 167                 break;
 168         }
 169         dev_dbg_obj(__func__, gobj);
 170 }
 171
 172 /**
 173  *  media_gobj_remove - Stop using a graph object on a media device
 174  *
 175  * @graph_obj:  Pointer to the object
 176  *
 177  * This should be called at media_device_unregister_*() routines
 178  */
 179 void media_gobj_remove(struct media_gobj *gobj)
 180 {
 181         dev_dbg_obj(__func__, gobj);
 182 }
 183
 184 /**
 185  * media_entity_init - Initialize a media entity
 186  *
 187  * @num_pads: Total number of sink and source pads.
 188  * @pads: Array of 'num_pads' pads.
 189  *
 190  * The total number of pads is an intrinsic property of entities known by the
 191  * entity driver, while the total number of links depends on hardware design
 192  * and is an extrinsic property unknown to the entity driver. However, in most
 193  * use cases the number of links can safely be assumed to be equal to or
 194  * larger than the number of pads.
 195  *
 196  * For those reasons the links array can be preallocated based on the number
 197  * of pads and will be reallocated later if extra links need to be created.
 198  *
 199  * This function allocates a links array with enough space to hold at least
 200  * 'num_pads' elements. The media_entity::max_links field will be set to the
 201  * number of allocated elements.
 202  *
 203  * The pads array is managed by the entity driver and passed to
 204  * media_entity_init() where its pointer will be stored in the entity structure.
 205  */
 206 int
 207 media_entity_init(struct media_entity *entity, u16 num_pads,
 208                   struct media_pad *pads)
 209 {
 210         unsigned int i;
 211
 212         entity->group_id = 0;
 213         entity->num_links = 0;
 214         entity->num_backlinks = 0;
 215         entity->num_pads = num_pads;
 216         entity->pads = pads;
 217
 218         for (i = 0; i < num_pads; i++) {
 219                 pads[i].entity = entity;
 220                 pads[i].index = i;
 221         }
 222
 223         return 0;
 224 }
 225 EXPORT_SYMBOL_GPL(media_entity_init);
 226
 227 void
 228 media_entity_cleanup(struct media_entity *entity)
 229 {
 230         struct media_link *link, *tmp;
 231
 232         list_for_each_entry_safe(link, tmp, &entity->links, list) {
 233                 media_gobj_remove(&link->graph_obj);
 234                 list_del(&link->list);
 235                 kfree(link);
 236         }
 237 }
 238 EXPORT_SYMBOL_GPL(media_entity_cleanup);
 239
 240 /* -----------------------------------------------------------------------------
 241  * Graph traversal
 242  */
 243
 244 static struct media_entity *
 245 media_entity_other(struct media_entity *entity, struct media_link *link)
 246 {
 247         if (link->source->entity == entity)
 248                 return link->sink->entity;
 249         else
 250                 return link->source->entity;
 251 }
 252
 253 /* push an entity to traversal stack */
 254 static void stack_push(struct media_entity_graph *graph,
 255                        struct media_entity *entity)
 256 {
 257         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 258                 WARN_ON(1);
 259                 return;
 260         }
 261         graph->top++;
 262         graph->stack[graph->top].link = (&entity->links)->next;
 263         graph->stack[graph->top].entity = entity;
 264 }
 265
 266 static struct media_entity *stack_pop(struct media_entity_graph *graph)
 267 {
 268         struct media_entity *entity;
 269
 270         entity = graph->stack[graph->top].entity;
 271         graph->top--;
 272
 273         return entity;
 274 }
 275
 276 #define link_top(en)    ((en)->stack[(en)->top].link)
 277 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 278
 279 /**
 280  * media_entity_graph_walk_start - Start walking the media graph at a given entity
 281  * @graph: Media graph structure that will be used to walk the graph
 282  * @entity: Starting entity
 283  *
 284  * This function initializes the graph traversal structure to walk the entities
 285  * graph starting at the given entity. The traversal structure must not be
 286  * modified by the caller during graph traversal. When done the structure can
 287  * safely be freed.
 288  */
 289 void media_entity_graph_walk_start(struct media_entity_graph *graph,
 290                                    struct media_entity *entity)
 291 {
 292         graph->top = 0;
 293         graph->stack[graph->top].entity = NULL;
 294         bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID);
 295
 296         if (WARN_ON(media_entity_id(entity) >= MEDIA_ENTITY_ENUM_MAX_ID))
 297                 return;
 298
 299         __set_bit(media_entity_id(entity), graph->entities);
 300         stack_push(graph, entity);
 301 }
 302 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
 303
 304
 305 /**
 306  * media_entity_graph_walk_next - Get the next entity in the graph
 307  * @graph: Media graph structure
 308  *
 309  * Perform a depth-first traversal of the given media entities graph.
 310  *
 311  * The graph structure must have been previously initialized with a call to
 312  * media_entity_graph_walk_start().
 313  *
 314  * Return the next entity in the graph or NULL if the whole graph have been
 315  * traversed.
 316  */
 317 struct media_entity *
 318 media_entity_graph_walk_next(struct media_entity_graph *graph)
 319 {
 320         if (stack_top(graph) == NULL)
 321                 return NULL;
 322
 323         /*
 324          * Depth first search. Push entity to stack and continue from
 325          * top of the stack until no more entities on the level can be
 326          * found.
 327          */
 328         while (link_top(graph) != &(stack_top(graph)->links)) {
 329                 struct media_entity *entity = stack_top(graph);
 330                 struct media_link *link;
 331                 struct media_entity *next;
 332
 333                 link = list_entry(link_top(graph), typeof(*link), list);
 334
 335                 /* The link is not enabled so we do not follow. */
 336                 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 337                         link_top(graph) = link_top(graph)->next;
 338                         continue;
 339                 }
 340
 341                 /* Get the entity in the other end of the link . */
 342                 next = media_entity_other(entity, link);
 343                 if (WARN_ON(media_entity_id(next) >= MEDIA_ENTITY_ENUM_MAX_ID))
 344                         return NULL;
 345
 346                 /* Has the entity already been visited? */
 347                 if (__test_and_set_bit(media_entity_id(next), graph->entities)) {
 348                         link_top(graph) = link_top(graph)->next;
 349                         continue;
 350                 }
 351
 352                 /* Push the new entity to stack and start over. */
 353                 link_top(graph) = link_top(graph)->next;
 354                 stack_push(graph, next);
 355         }
 356
 357         return stack_pop(graph);
 358 }
 359 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
 360
 361 /* -----------------------------------------------------------------------------
 362  * Pipeline management
 363  */
 364
 365 /**
 366  * media_entity_pipeline_start - Mark a pipeline as streaming
 367  * @entity: Starting entity
 368  * @pipe: Media pipeline to be assigned to all entities in the pipeline.
 369  *
 370  * Mark all entities connected to a given entity through enabled links, either
 371  * directly or indirectly, as streaming. The given pipeline object is assigned to
 372  * every entity in the pipeline and stored in the media_entity pipe field.
 373  *
 374  * Calls to this function can be nested, in which case the same number of
 375  * media_entity_pipeline_stop() calls will be required to stop streaming. The
 376  * pipeline pointer must be identical for all nested calls to
 377  * media_entity_pipeline_start().
 378  */
 379 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 380                                              struct media_pipeline *pipe)
 381 {
 382         struct media_device *mdev = entity->graph_obj.mdev;
 383         struct media_entity_graph graph;
 384         struct media_entity *entity_err = entity;
 385         struct media_link *link;
 386         int ret;
 387
 388         mutex_lock(&mdev->graph_mutex);
 389
 390         media_entity_graph_walk_start(&graph, entity);
 391
 392         while ((entity = media_entity_graph_walk_next(&graph))) {
 393                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 394                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 395
 396                 entity->stream_count++;
 397                 WARN_ON(entity->pipe && entity->pipe != pipe);
 398                 entity->pipe = pipe;
 399
 400                 /* Already streaming --- no need to check. */
 401                 if (entity->stream_count > 1)
 402                         continue;
 403
 404                 if (!entity->ops || !entity->ops->link_validate)
 405                         continue;
 406
 407                 bitmap_zero(active, entity->num_pads);
 408                 bitmap_fill(has_no_links, entity->num_pads);
 409
 410                 list_for_each_entry(link, &entity->links, list) {
 411                         struct media_pad *pad = link->sink->entity == entity
 412                                                 ? link->sink : link->source;
 413
 414                         /* Mark that a pad is connected by a link. */
 415                         bitmap_clear(has_no_links, pad->index, 1);
 416
 417                         /*
 418                          * Pads that either do not need to connect or
 419                          * are connected through an enabled link are
 420                          * fine.
 421                          */
 422                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 423                             link->flags & MEDIA_LNK_FL_ENABLED)
 424                                 bitmap_set(active, pad->index, 1);
 425
 426                         /*
 427                          * Link validation will only take place for
 428                          * sink ends of the link that are enabled.
 429                          */
 430                         if (link->sink != pad ||
 431                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 432                                 continue;
 433
 434                         ret = entity->ops->link_validate(link);
 435                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 436                                 dev_dbg(entity->graph_obj.mdev->dev,
 437                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 438                                         link->source->entity->name,
 439                                         link->source->index,
 440                                         entity->name, link->sink->index, ret);
 441                                 goto error;
 442                         }
 443                 }
 444
 445                 /* Either no links or validated links are fine. */
 446                 bitmap_or(active, active, has_no_links, entity->num_pads);
 447
 448                 if (!bitmap_full(active, entity->num_pads)) {
 449                         ret = -EPIPE;
 450                         dev_dbg(entity->graph_obj.mdev->dev,
 451                                 "\"%s\":%u must be connected by an enabled link\n",
 452                                 entity->name,
 453                                 (unsigned)find_first_zero_bit(
 454                                         active, entity->num_pads));
 455                         goto error;
 456                 }
 457         }
 458
 459         mutex_unlock(&mdev->graph_mutex);
 460
 461         return 0;
 462
 463 error:
 464         /*
 465          * Link validation on graph failed. We revert what we did and
 466          * return the error.
 467          */
 468         media_entity_graph_walk_start(&graph, entity_err);
 469
 470         while ((entity_err = media_entity_graph_walk_next(&graph))) {
 471                 entity_err->stream_count--;
 472                 if (entity_err->stream_count == 0)
 473                         entity_err->pipe = NULL;
 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         mutex_unlock(&mdev->graph_mutex);
 484
 485         return ret;
 486 }
 487 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 488
 489 /**
 490  * media_entity_pipeline_stop - Mark a pipeline as not streaming
 491  * @entity: Starting entity
 492  *
 493  * Mark all entities connected to a given entity through enabled links, either
 494  * directly or indirectly, as not streaming. The media_entity pipe field is
 495  * reset to NULL.
 496  *
 497  * If multiple calls to media_entity_pipeline_start() have been made, the same
 498  * number of calls to this function are required to mark the pipeline as not
 499  * streaming.
 500  */
 501 void media_entity_pipeline_stop(struct media_entity *entity)
 502 {
 503         struct media_device *mdev = entity->graph_obj.mdev;
 504         struct media_entity_graph graph;
 505
 506         mutex_lock(&mdev->graph_mutex);
 507
 508         media_entity_graph_walk_start(&graph, entity);
 509
 510         while ((entity = media_entity_graph_walk_next(&graph))) {
 511                 entity->stream_count--;
 512                 if (entity->stream_count == 0)
 513                         entity->pipe = NULL;
 514         }
 515
 516         mutex_unlock(&mdev->graph_mutex);
 517 }
 518 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
 519
 520 /* -----------------------------------------------------------------------------
 521  * Module use count
 522  */
 523
 524 /*
 525  * media_entity_get - Get a reference to the parent module
 526  * @entity: The entity
 527  *
 528  * Get a reference to the parent media device module.
 529  *
 530  * The function will return immediately if @entity is NULL.
 531  *
 532  * Return a pointer to the entity on success or NULL on failure.
 533  */
 534 struct media_entity *media_entity_get(struct media_entity *entity)
 535 {
 536         if (entity == NULL)
 537                 return NULL;
 538
 539         if (entity->graph_obj.mdev->dev &&
 540             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 541                 return NULL;
 542
 543         return entity;
 544 }
 545 EXPORT_SYMBOL_GPL(media_entity_get);
 546
 547 /*
 548  * media_entity_put - Release the reference to the parent module
 549  * @entity: The entity
 550  *
 551  * Release the reference count acquired by media_entity_get().
 552  *
 553  * The function will return immediately if @entity is NULL.
 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 int
 586 media_create_pad_link(struct media_entity *source, u16 source_pad,
 587                          struct media_entity *sink, u16 sink_pad, u32 flags)
 588 {
 589         struct media_link *link;
 590         struct media_link *backlink;
 591
 592         BUG_ON(source == NULL || sink == NULL);
 593         BUG_ON(source_pad >= source->num_pads);
 594         BUG_ON(sink_pad >= sink->num_pads);
 595
 596         link = media_add_link(&source->links);
 597         if (link == NULL)
 598                 return -ENOMEM;
 599
 600         link->source = &source->pads[source_pad];
 601         link->sink = &sink->pads[sink_pad];
 602         link->flags = flags;
 603
 604         /* Initialize graph object embedded at the new link */
 605         media_gobj_init(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 606                         &link->graph_obj);
 607
 608         /* Create the backlink. Backlinks are used to help graph traversal and
 609          * are not reported to userspace.
 610          */
 611         backlink = media_add_link(&sink->links);
 612         if (backlink == NULL) {
 613                 __media_entity_remove_link(source, link);
 614                 return -ENOMEM;
 615         }
 616
 617         backlink->source = &source->pads[source_pad];
 618         backlink->sink = &sink->pads[sink_pad];
 619         backlink->flags = flags;
 620
 621         /* Initialize graph object embedded at the new link */
 622         media_gobj_init(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 623                         &backlink->graph_obj);
 624
 625         link->reverse = backlink;
 626         backlink->reverse = link;
 627
 628         sink->num_backlinks++;
 629         sink->num_links++;
 630         source->num_links++;
 631
 632         return 0;
 633 }
 634 EXPORT_SYMBOL_GPL(media_create_pad_link);
 635
 636 static void __media_entity_remove_link(struct media_entity *entity,
 637                                        struct media_link *link)
 638 {
 639         struct media_link *rlink, *tmp;
 640         struct media_entity *remote;
 641         unsigned int r = 0;
 642
 643         if (link->source->entity == entity)
 644                 remote = link->sink->entity;
 645         else
 646                 remote = link->source->entity;
 647
 648         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 649                 if (rlink != link->reverse) {
 650                         r++;
 651                         continue;
 652                 }
 653
 654                 if (link->source->entity == entity)
 655                         remote->num_backlinks--;
 656
 657                 if (--remote->num_links == 0)
 658                         break;
 659
 660                 /* Remove the remote link */
 661                 list_del(&rlink->list);
 662                 kfree(rlink);
 663         }
 664         list_del(&link->list);
 665         kfree(link);
 666 }
 667
 668 void __media_entity_remove_links(struct media_entity *entity)
 669 {
 670         struct media_link *link, *tmp;
 671
 672         list_for_each_entry_safe(link, tmp, &entity->links, list)
 673                 __media_entity_remove_link(entity, link);
 674
 675         entity->num_links = 0;
 676         entity->num_backlinks = 0;
 677 }
 678 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 679
 680 void media_entity_remove_links(struct media_entity *entity)
 681 {
 682         /* Do nothing if the entity is not registered. */
 683         if (entity->graph_obj.mdev == NULL)
 684                 return;
 685
 686         mutex_lock(&entity->graph_obj.mdev->graph_mutex);
 687         __media_entity_remove_links(entity);
 688         mutex_unlock(&entity->graph_obj.mdev->graph_mutex);
 689 }
 690 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 691
 692 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 693 {
 694         int ret;
 695
 696         /* Notify both entities. */
 697         ret = media_entity_call(link->source->entity, link_setup,
 698                                 link->source, link->sink, flags);
 699         if (ret < 0 && ret != -ENOIOCTLCMD)
 700                 return ret;
 701
 702         ret = media_entity_call(link->sink->entity, link_setup,
 703                                 link->sink, link->source, flags);
 704         if (ret < 0 && ret != -ENOIOCTLCMD) {
 705                 media_entity_call(link->source->entity, link_setup,
 706                                   link->source, link->sink, link->flags);
 707                 return ret;
 708         }
 709
 710         link->flags = flags;
 711         link->reverse->flags = link->flags;
 712
 713         return 0;
 714 }
 715
 716 /**
 717  * __media_entity_setup_link - Configure a media link
 718  * @link: The link being configured
 719  * @flags: Link configuration flags
 720  *
 721  * The bulk of link setup is handled by the two entities connected through the
 722  * link. This function notifies both entities of the link configuration change.
 723  *
 724  * If the link is immutable or if the current and new configuration are
 725  * identical, return immediately.
 726  *
 727  * The user is expected to hold link->source->parent->mutex. If not,
 728  * media_entity_setup_link() should be used instead.
 729  */
 730 int __media_entity_setup_link(struct media_link *link, u32 flags)
 731 {
 732         const u32 mask = MEDIA_LNK_FL_ENABLED;
 733         struct media_device *mdev;
 734         struct media_entity *source, *sink;
 735         int ret = -EBUSY;
 736
 737         if (link == NULL)
 738                 return -EINVAL;
 739
 740         /* The non-modifiable link flags must not be modified. */
 741         if ((link->flags & ~mask) != (flags & ~mask))
 742                 return -EINVAL;
 743
 744         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 745                 return link->flags == flags ? 0 : -EINVAL;
 746
 747         if (link->flags == flags)
 748                 return 0;
 749
 750         source = link->source->entity;
 751         sink = link->sink->entity;
 752
 753         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 754             (source->stream_count || sink->stream_count))
 755                 return -EBUSY;
 756
 757         mdev = source->graph_obj.mdev;
 758
 759         if (mdev->link_notify) {
 760                 ret = mdev->link_notify(link, flags,
 761                                         MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 762                 if (ret < 0)
 763                         return ret;
 764         }
 765
 766         ret = __media_entity_setup_link_notify(link, flags);
 767
 768         if (mdev->link_notify)
 769                 mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);
 770
 771         return ret;
 772 }
 773
 774 int media_entity_setup_link(struct media_link *link, u32 flags)
 775 {
 776         int ret;
 777
 778         mutex_lock(&link->source->entity->graph_obj.mdev->graph_mutex);
 779         ret = __media_entity_setup_link(link, flags);
 780         mutex_unlock(&link->source->entity->graph_obj.mdev->graph_mutex);
 781
 782         return ret;
 783 }
 784 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 785
 786 /**
 787  * media_entity_find_link - Find a link between two pads
 788  * @source: Source pad
 789  * @sink: Sink pad
 790  *
 791  * Return a pointer to the link between the two entities. If no such link
 792  * exists, return NULL.
 793  */
 794 struct media_link *
 795 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 796 {
 797         struct media_link *link;
 798
 799         list_for_each_entry(link, &source->entity->links, list) {
 800                 if (link->source->entity == source->entity &&
 801                     link->source->index == source->index &&
 802                     link->sink->entity == sink->entity &&
 803                     link->sink->index == sink->index)
 804                         return link;
 805         }
 806
 807         return NULL;
 808 }
 809 EXPORT_SYMBOL_GPL(media_entity_find_link);
 810
 811 /**
 812  * media_entity_remote_pad - Find the pad at the remote end of a link
 813  * @pad: Pad at the local end of the link
 814  *
 815  * Search for a remote pad connected to the given pad by iterating over all
 816  * links originating or terminating at that pad until an enabled link is found.
 817  *
 818  * Return a pointer to the pad at the remote end of the first found enabled
 819  * link, or NULL if no enabled link has been found.
 820  */
 821 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 822 {
 823         struct media_link *link;
 824
 825         list_for_each_entry(link, &pad->entity->links, list) {
 826                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 827                         continue;
 828
 829                 if (link->source == pad)
 830                         return link->sink;
 831
 832                 if (link->sink == pad)
 833                         return link->source;
 834         }
 835
 836         return NULL;
 837
 838 }
 839 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 840
 841
 842 static void media_interface_init(struct media_device *mdev,
 843                                  struct media_interface *intf,
 844                                  u32 gobj_type,
 845                                  u32 intf_type, u32 flags)
 846 {
 847         intf->type = intf_type;
 848         intf->flags = flags;
 849         INIT_LIST_HEAD(&intf->links);
 850
 851         media_gobj_init(mdev, gobj_type, &intf->graph_obj);
 852 }
 853
 854 /* Functions related to the media interface via device nodes */
 855
 856 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 857                                                 u32 type, u32 flags,
 858                                                 u32 major, u32 minor,
 859                                                 gfp_t gfp_flags)
 860 {
 861         struct media_intf_devnode *devnode;
 862
 863         devnode = kzalloc(sizeof(*devnode), gfp_flags);
 864         if (!devnode)
 865                 return NULL;
 866
 867         devnode->major = major;
 868         devnode->minor = minor;
 869
 870         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 871                              type, flags);
 872
 873         return devnode;
 874 }
 875 EXPORT_SYMBOL_GPL(media_devnode_create);
 876
 877 void media_devnode_remove(struct media_intf_devnode *devnode)
 878 {
 879         media_gobj_remove(&devnode->intf.graph_obj);
 880         kfree(devnode);
 881 }
 882 EXPORT_SYMBOL_GPL(media_devnode_remove);
 883
 884 struct media_link *media_create_intf_link(struct media_entity *entity,
 885                                             struct media_interface *intf,
 886                                             u32 flags)
 887 {
 888         struct media_link *link;
 889
 890         link = media_add_link(&intf->links);
 891         if (link == NULL)
 892                 return NULL;
 893
 894         link->intf = intf;
 895         link->entity = entity;
 896         link->flags = flags;
 897
 898         /* Initialize graph object embedded at the new link */
 899         media_gobj_init(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 900                         &link->graph_obj);
 901
 902         return link;
 903 }
 904 EXPORT_SYMBOL_GPL(media_create_intf_link);
 905
 906
 907 static void __media_remove_intf_link(struct media_link *link)
 908 {
 909         media_gobj_remove(&link->graph_obj);
 910         kfree(link);
 911 }
 912
 913 void media_remove_intf_link(struct media_link *link)
 914 {
 915         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 916         __media_remove_intf_link(link);
 917         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 918 }
 919 EXPORT_SYMBOL_GPL(media_remove_intf_link);