blob: 37c334edc7e8c10d3a6430f64a29b1f16088d929 [file] [log] [blame]
Laurent Pinchart53e269c2009-12-09 08:40:00 -03001/*
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
Laurent Pinchart5c7b25b2013-06-07 12:45:11 -030023#include <linux/bitmap.h>
Laurent Pinchart53e269c2009-12-09 08:40:00 -030024#include <linux/module.h>
25#include <linux/slab.h>
26#include <media/media-entity.h>
Laurent Pinchart503c3d822010-03-07 15:04:59 -030027#include <media/media-device.h>
Laurent Pinchart53e269c2009-12-09 08:40:00 -030028
29/**
30 * media_entity_init - Initialize a media entity
31 *
32 * @num_pads: Total number of sink and source pads.
33 * @extra_links: Initial estimate of the number of extra links.
34 * @pads: Array of 'num_pads' pads.
35 *
36 * The total number of pads is an intrinsic property of entities known by the
37 * entity driver, while the total number of links depends on hardware design
38 * and is an extrinsic property unknown to the entity driver. However, in most
39 * use cases the entity driver can guess the number of links which can safely
40 * be assumed to be equal to or larger than the number of pads.
41 *
42 * For those reasons the links array can be preallocated based on the entity
43 * driver guess and will be reallocated later if extra links need to be
44 * created.
45 *
46 * This function allocates a links array with enough space to hold at least
47 * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
48 * be set to the number of allocated elements.
49 *
50 * The pads array is managed by the entity driver and passed to
51 * media_entity_init() where its pointer will be stored in the entity structure.
52 */
53int
54media_entity_init(struct media_entity *entity, u16 num_pads,
55 struct media_pad *pads, u16 extra_links)
56{
57 struct media_link *links;
58 unsigned int max_links = num_pads + extra_links;
59 unsigned int i;
60
61 links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
62 if (links == NULL)
63 return -ENOMEM;
64
65 entity->group_id = 0;
66 entity->max_links = max_links;
67 entity->num_links = 0;
68 entity->num_backlinks = 0;
69 entity->num_pads = num_pads;
70 entity->pads = pads;
71 entity->links = links;
72
73 for (i = 0; i < num_pads; i++) {
74 pads[i].entity = entity;
75 pads[i].index = i;
76 }
77
78 return 0;
79}
80EXPORT_SYMBOL_GPL(media_entity_init);
81
82void
83media_entity_cleanup(struct media_entity *entity)
84{
85 kfree(entity->links);
86}
87EXPORT_SYMBOL_GPL(media_entity_cleanup);
88
Sakari Ailusa5ccc482010-03-07 16:14:14 -030089/* -----------------------------------------------------------------------------
90 * Graph traversal
91 */
92
93static struct media_entity *
94media_entity_other(struct media_entity *entity, struct media_link *link)
95{
96 if (link->source->entity == entity)
97 return link->sink->entity;
98 else
99 return link->source->entity;
100}
101
102/* push an entity to traversal stack */
103static void stack_push(struct media_entity_graph *graph,
104 struct media_entity *entity)
105{
106 if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
107 WARN_ON(1);
108 return;
109 }
110 graph->top++;
111 graph->stack[graph->top].link = 0;
112 graph->stack[graph->top].entity = entity;
113}
114
115static struct media_entity *stack_pop(struct media_entity_graph *graph)
116{
117 struct media_entity *entity;
118
119 entity = graph->stack[graph->top].entity;
120 graph->top--;
121
122 return entity;
123}
124
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300125#define link_top(en) ((en)->stack[(en)->top].link)
126#define stack_top(en) ((en)->stack[(en)->top].entity)
127
128/**
129 * media_entity_graph_walk_start - Start walking the media graph at a given entity
130 * @graph: Media graph structure that will be used to walk the graph
131 * @entity: Starting entity
132 *
133 * This function initializes the graph traversal structure to walk the entities
134 * graph starting at the given entity. The traversal structure must not be
135 * modified by the caller during graph traversal. When done the structure can
136 * safely be freed.
137 */
138void media_entity_graph_walk_start(struct media_entity_graph *graph,
139 struct media_entity *entity)
140{
141 graph->top = 0;
142 graph->stack[graph->top].entity = NULL;
Laurent Pinchart5c7b25b2013-06-07 12:45:11 -0300143 bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID);
144
145 if (WARN_ON(entity->id >= MEDIA_ENTITY_ENUM_MAX_ID))
146 return;
147
148 __set_bit(entity->id, graph->entities);
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300149 stack_push(graph, entity);
150}
151EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
152
153/**
154 * media_entity_graph_walk_next - Get the next entity in the graph
155 * @graph: Media graph structure
156 *
157 * Perform a depth-first traversal of the given media entities graph.
158 *
159 * The graph structure must have been previously initialized with a call to
160 * media_entity_graph_walk_start().
161 *
162 * Return the next entity in the graph or NULL if the whole graph have been
163 * traversed.
164 */
165struct media_entity *
166media_entity_graph_walk_next(struct media_entity_graph *graph)
167{
168 if (stack_top(graph) == NULL)
169 return NULL;
170
171 /*
172 * Depth first search. Push entity to stack and continue from
173 * top of the stack until no more entities on the level can be
174 * found.
175 */
176 while (link_top(graph) < stack_top(graph)->num_links) {
177 struct media_entity *entity = stack_top(graph);
178 struct media_link *link = &entity->links[link_top(graph)];
179 struct media_entity *next;
180
181 /* The link is not enabled so we do not follow. */
182 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
183 link_top(graph)++;
184 continue;
185 }
186
187 /* Get the entity in the other end of the link . */
188 next = media_entity_other(entity, link);
Laurent Pinchart5c7b25b2013-06-07 12:45:11 -0300189 if (WARN_ON(next->id >= MEDIA_ENTITY_ENUM_MAX_ID))
190 return NULL;
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300191
Laurent Pinchart5c7b25b2013-06-07 12:45:11 -0300192 /* Has the entity already been visited? */
193 if (__test_and_set_bit(next->id, graph->entities)) {
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300194 link_top(graph)++;
195 continue;
196 }
197
198 /* Push the new entity to stack and start over. */
199 link_top(graph)++;
200 stack_push(graph, next);
201 }
202
203 return stack_pop(graph);
204}
205EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
206
207/* -----------------------------------------------------------------------------
Laurent Pincharte02188c2010-08-25 09:00:41 -0300208 * Pipeline management
209 */
210
211/**
212 * media_entity_pipeline_start - Mark a pipeline as streaming
213 * @entity: Starting entity
214 * @pipe: Media pipeline to be assigned to all entities in the pipeline.
215 *
216 * Mark all entities connected to a given entity through enabled links, either
217 * directly or indirectly, as streaming. The given pipeline object is assigned to
218 * every entity in the pipeline and stored in the media_entity pipe field.
219 *
220 * Calls to this function can be nested, in which case the same number of
221 * media_entity_pipeline_stop() calls will be required to stop streaming. The
222 * pipeline pointer must be identical for all nested calls to
223 * media_entity_pipeline_start().
224 */
Sakari Ailusaf88be32012-01-11 06:25:15 -0300225__must_check int media_entity_pipeline_start(struct media_entity *entity,
226 struct media_pipeline *pipe)
Laurent Pincharte02188c2010-08-25 09:00:41 -0300227{
228 struct media_device *mdev = entity->parent;
229 struct media_entity_graph graph;
Sakari Ailusaf88be32012-01-11 06:25:15 -0300230 struct media_entity *entity_err = entity;
231 int ret;
Laurent Pincharte02188c2010-08-25 09:00:41 -0300232
233 mutex_lock(&mdev->graph_mutex);
234
235 media_entity_graph_walk_start(&graph, entity);
236
237 while ((entity = media_entity_graph_walk_next(&graph))) {
Sakari Ailusde49c282013-10-13 08:00:26 -0300238 DECLARE_BITMAP(active, entity->num_pads);
239 DECLARE_BITMAP(has_no_links, entity->num_pads);
Sakari Ailusaf88be32012-01-11 06:25:15 -0300240 unsigned int i;
241
Laurent Pincharte02188c2010-08-25 09:00:41 -0300242 entity->stream_count++;
243 WARN_ON(entity->pipe && entity->pipe != pipe);
244 entity->pipe = pipe;
Sakari Ailusaf88be32012-01-11 06:25:15 -0300245
246 /* Already streaming --- no need to check. */
247 if (entity->stream_count > 1)
248 continue;
249
250 if (!entity->ops || !entity->ops->link_validate)
251 continue;
252
Sakari Ailusde49c282013-10-13 08:00:26 -0300253 bitmap_zero(active, entity->num_pads);
254 bitmap_fill(has_no_links, entity->num_pads);
255
Sakari Ailusaf88be32012-01-11 06:25:15 -0300256 for (i = 0; i < entity->num_links; i++) {
257 struct media_link *link = &entity->links[i];
Sakari Ailusde49c282013-10-13 08:00:26 -0300258 struct media_pad *pad = link->sink->entity == entity
259 ? link->sink : link->source;
Sakari Ailusaf88be32012-01-11 06:25:15 -0300260
Sakari Ailusde49c282013-10-13 08:00:26 -0300261 /* Mark that a pad is connected by a link. */
262 bitmap_clear(has_no_links, pad->index, 1);
Sakari Ailusaf88be32012-01-11 06:25:15 -0300263
Sakari Ailusde49c282013-10-13 08:00:26 -0300264 /*
265 * Pads that either do not need to connect or
266 * are connected through an enabled link are
267 * fine.
268 */
269 if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
270 link->flags & MEDIA_LNK_FL_ENABLED)
271 bitmap_set(active, pad->index, 1);
272
273 /*
274 * Link validation will only take place for
275 * sink ends of the link that are enabled.
276 */
277 if (link->sink != pad ||
278 !(link->flags & MEDIA_LNK_FL_ENABLED))
Sakari Ailusaf88be32012-01-11 06:25:15 -0300279 continue;
280
281 ret = entity->ops->link_validate(link);
282 if (ret < 0 && ret != -ENOIOCTLCMD)
283 goto error;
284 }
Sakari Ailusde49c282013-10-13 08:00:26 -0300285
286 /* Either no links or validated links are fine. */
287 bitmap_or(active, active, has_no_links, entity->num_pads);
288
289 if (!bitmap_full(active, entity->num_pads)) {
290 ret = -EPIPE;
291 goto error;
292 }
Laurent Pincharte02188c2010-08-25 09:00:41 -0300293 }
294
295 mutex_unlock(&mdev->graph_mutex);
Sakari Ailusaf88be32012-01-11 06:25:15 -0300296
297 return 0;
298
299error:
300 /*
301 * Link validation on graph failed. We revert what we did and
302 * return the error.
303 */
304 media_entity_graph_walk_start(&graph, entity_err);
305
306 while ((entity_err = media_entity_graph_walk_next(&graph))) {
307 entity_err->stream_count--;
308 if (entity_err->stream_count == 0)
309 entity_err->pipe = NULL;
310
311 /*
312 * We haven't increased stream_count further than this
313 * so we quit here.
314 */
315 if (entity_err == entity)
316 break;
317 }
318
319 mutex_unlock(&mdev->graph_mutex);
320
321 return ret;
Laurent Pincharte02188c2010-08-25 09:00:41 -0300322}
323EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
324
325/**
326 * media_entity_pipeline_stop - Mark a pipeline as not streaming
327 * @entity: Starting entity
328 *
329 * Mark all entities connected to a given entity through enabled links, either
330 * directly or indirectly, as not streaming. The media_entity pipe field is
331 * reset to NULL.
332 *
333 * If multiple calls to media_entity_pipeline_start() have been made, the same
334 * number of calls to this function are required to mark the pipeline as not
335 * streaming.
336 */
337void media_entity_pipeline_stop(struct media_entity *entity)
338{
339 struct media_device *mdev = entity->parent;
340 struct media_entity_graph graph;
341
342 mutex_lock(&mdev->graph_mutex);
343
344 media_entity_graph_walk_start(&graph, entity);
345
346 while ((entity = media_entity_graph_walk_next(&graph))) {
347 entity->stream_count--;
348 if (entity->stream_count == 0)
349 entity->pipe = NULL;
350 }
351
352 mutex_unlock(&mdev->graph_mutex);
353}
354EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
355
356/* -----------------------------------------------------------------------------
Laurent Pinchart503c3d822010-03-07 15:04:59 -0300357 * Module use count
358 */
359
360/*
361 * media_entity_get - Get a reference to the parent module
362 * @entity: The entity
363 *
364 * Get a reference to the parent media device module.
365 *
366 * The function will return immediately if @entity is NULL.
367 *
368 * Return a pointer to the entity on success or NULL on failure.
369 */
370struct media_entity *media_entity_get(struct media_entity *entity)
371{
372 if (entity == NULL)
373 return NULL;
374
375 if (entity->parent->dev &&
376 !try_module_get(entity->parent->dev->driver->owner))
377 return NULL;
378
379 return entity;
380}
381EXPORT_SYMBOL_GPL(media_entity_get);
382
383/*
384 * media_entity_put - Release the reference to the parent module
385 * @entity: The entity
386 *
387 * Release the reference count acquired by media_entity_get().
388 *
389 * The function will return immediately if @entity is NULL.
390 */
391void media_entity_put(struct media_entity *entity)
392{
393 if (entity == NULL)
394 return;
395
396 if (entity->parent->dev)
397 module_put(entity->parent->dev->driver->owner);
398}
399EXPORT_SYMBOL_GPL(media_entity_put);
400
401/* -----------------------------------------------------------------------------
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300402 * Links management
403 */
404
Laurent Pinchart53e269c2009-12-09 08:40:00 -0300405static struct media_link *media_entity_add_link(struct media_entity *entity)
406{
407 if (entity->num_links >= entity->max_links) {
408 struct media_link *links = entity->links;
409 unsigned int max_links = entity->max_links + 2;
410 unsigned int i;
411
412 links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
413 if (links == NULL)
414 return NULL;
415
416 for (i = 0; i < entity->num_links; i++)
417 links[i].reverse->reverse = &links[i];
418
419 entity->max_links = max_links;
420 entity->links = links;
421 }
422
423 return &entity->links[entity->num_links++];
424}
425
426int
427media_entity_create_link(struct media_entity *source, u16 source_pad,
428 struct media_entity *sink, u16 sink_pad, u32 flags)
429{
430 struct media_link *link;
431 struct media_link *backlink;
432
433 BUG_ON(source == NULL || sink == NULL);
434 BUG_ON(source_pad >= source->num_pads);
435 BUG_ON(sink_pad >= sink->num_pads);
436
437 link = media_entity_add_link(source);
438 if (link == NULL)
439 return -ENOMEM;
440
441 link->source = &source->pads[source_pad];
442 link->sink = &sink->pads[sink_pad];
443 link->flags = flags;
444
445 /* Create the backlink. Backlinks are used to help graph traversal and
446 * are not reported to userspace.
447 */
448 backlink = media_entity_add_link(sink);
449 if (backlink == NULL) {
450 source->num_links--;
451 return -ENOMEM;
452 }
453
454 backlink->source = &source->pads[source_pad];
455 backlink->sink = &sink->pads[sink_pad];
456 backlink->flags = flags;
457
458 link->reverse = backlink;
459 backlink->reverse = link;
460
461 sink->num_backlinks++;
462
463 return 0;
464}
465EXPORT_SYMBOL_GPL(media_entity_create_link);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300466
Sylwester Nawrocki7349cec2013-05-09 08:29:32 -0300467void __media_entity_remove_links(struct media_entity *entity)
468{
469 unsigned int i;
470
471 for (i = 0; i < entity->num_links; i++) {
472 struct media_link *link = &entity->links[i];
473 struct media_entity *remote;
474 unsigned int r = 0;
475
476 if (link->source->entity == entity)
477 remote = link->sink->entity;
478 else
479 remote = link->source->entity;
480
481 while (r < remote->num_links) {
482 struct media_link *rlink = &remote->links[r];
483
484 if (rlink != link->reverse) {
485 r++;
486 continue;
487 }
488
489 if (link->source->entity == entity)
490 remote->num_backlinks--;
491
492 if (--remote->num_links == 0)
493 break;
494
495 /* Insert last entry in place of the dropped link. */
496 *rlink = remote->links[remote->num_links];
497 }
498 }
499
500 entity->num_links = 0;
501 entity->num_backlinks = 0;
502}
503EXPORT_SYMBOL_GPL(__media_entity_remove_links);
504
505void media_entity_remove_links(struct media_entity *entity)
506{
507 /* Do nothing if the entity is not registered. */
508 if (entity->parent == NULL)
509 return;
510
511 mutex_lock(&entity->parent->graph_mutex);
512 __media_entity_remove_links(entity);
513 mutex_unlock(&entity->parent->graph_mutex);
514}
515EXPORT_SYMBOL_GPL(media_entity_remove_links);
516
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300517static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
518{
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300519 int ret;
520
521 /* Notify both entities. */
522 ret = media_entity_call(link->source->entity, link_setup,
523 link->source, link->sink, flags);
524 if (ret < 0 && ret != -ENOIOCTLCMD)
525 return ret;
526
527 ret = media_entity_call(link->sink->entity, link_setup,
528 link->sink, link->source, flags);
529 if (ret < 0 && ret != -ENOIOCTLCMD) {
530 media_entity_call(link->source->entity, link_setup,
531 link->source, link->sink, link->flags);
532 return ret;
533 }
534
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300535 link->flags = flags;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300536 link->reverse->flags = link->flags;
537
538 return 0;
539}
540
541/**
542 * __media_entity_setup_link - Configure a media link
543 * @link: The link being configured
544 * @flags: Link configuration flags
545 *
546 * The bulk of link setup is handled by the two entities connected through the
547 * link. This function notifies both entities of the link configuration change.
548 *
549 * If the link is immutable or if the current and new configuration are
550 * identical, return immediately.
551 *
552 * The user is expected to hold link->source->parent->mutex. If not,
553 * media_entity_setup_link() should be used instead.
554 */
555int __media_entity_setup_link(struct media_link *link, u32 flags)
556{
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300557 const u32 mask = MEDIA_LNK_FL_ENABLED;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300558 struct media_device *mdev;
559 struct media_entity *source, *sink;
560 int ret = -EBUSY;
561
562 if (link == NULL)
563 return -EINVAL;
564
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300565 /* The non-modifiable link flags must not be modified. */
566 if ((link->flags & ~mask) != (flags & ~mask))
567 return -EINVAL;
568
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300569 if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
570 return link->flags == flags ? 0 : -EINVAL;
571
572 if (link->flags == flags)
573 return 0;
574
575 source = link->source->entity;
576 sink = link->sink->entity;
577
Laurent Pincharte02188c2010-08-25 09:00:41 -0300578 if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
579 (source->stream_count || sink->stream_count))
580 return -EBUSY;
581
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300582 mdev = source->parent;
583
Sylwester Nawrocki813f5c02013-05-31 10:37:26 -0300584 if (mdev->link_notify) {
585 ret = mdev->link_notify(link, flags,
586 MEDIA_DEV_NOTIFY_PRE_LINK_CH);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300587 if (ret < 0)
588 return ret;
589 }
590
591 ret = __media_entity_setup_link_notify(link, flags);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300592
Sylwester Nawrocki813f5c02013-05-31 10:37:26 -0300593 if (mdev->link_notify)
594 mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300595
596 return ret;
597}
598
599int media_entity_setup_link(struct media_link *link, u32 flags)
600{
601 int ret;
602
603 mutex_lock(&link->source->entity->parent->graph_mutex);
604 ret = __media_entity_setup_link(link, flags);
605 mutex_unlock(&link->source->entity->parent->graph_mutex);
606
607 return ret;
608}
609EXPORT_SYMBOL_GPL(media_entity_setup_link);
610
611/**
612 * media_entity_find_link - Find a link between two pads
613 * @source: Source pad
614 * @sink: Sink pad
615 *
616 * Return a pointer to the link between the two entities. If no such link
617 * exists, return NULL.
618 */
619struct media_link *
620media_entity_find_link(struct media_pad *source, struct media_pad *sink)
621{
622 struct media_link *link;
623 unsigned int i;
624
625 for (i = 0; i < source->entity->num_links; ++i) {
626 link = &source->entity->links[i];
627
628 if (link->source->entity == source->entity &&
629 link->source->index == source->index &&
630 link->sink->entity == sink->entity &&
631 link->sink->index == sink->index)
632 return link;
633 }
634
635 return NULL;
636}
637EXPORT_SYMBOL_GPL(media_entity_find_link);
638
639/**
Andrzej Hajda1bddf1b2013-06-03 05:16:13 -0300640 * media_entity_remote_pad - Find the pad at the remote end of a link
641 * @pad: Pad at the local end of the link
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300642 *
Andrzej Hajda1bddf1b2013-06-03 05:16:13 -0300643 * Search for a remote pad connected to the given pad by iterating over all
644 * links originating or terminating at that pad until an enabled link is found.
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300645 *
646 * Return a pointer to the pad at the remote end of the first found enabled
647 * link, or NULL if no enabled link has been found.
648 */
Andrzej Hajda1bddf1b2013-06-03 05:16:13 -0300649struct media_pad *media_entity_remote_pad(struct media_pad *pad)
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300650{
651 unsigned int i;
652
653 for (i = 0; i < pad->entity->num_links; i++) {
654 struct media_link *link = &pad->entity->links[i];
655
656 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
657 continue;
658
659 if (link->source == pad)
660 return link->sink;
661
662 if (link->sink == pad)
663 return link->source;
664 }
665
666 return NULL;
667
668}
Andrzej Hajda1bddf1b2013-06-03 05:16:13 -0300669EXPORT_SYMBOL_GPL(media_entity_remote_pad);