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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Media entity
4 *
5 * Copyright (C) 2010 Nokia Corporation
6 *
7 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
8 * Sakari Ailus <sakari.ailus@iki.fi>
9 */
10
11#include <linux/bitmap.h>
12#include <linux/list.h>
13#include <linux/property.h>
14#include <linux/slab.h>
15#include <media/media-entity.h>
16#include <media/media-device.h>
17
18static inline const char *intf_type(struct media_interface *intf)
19{
20 switch (intf->type) {
21 case MEDIA_INTF_T_DVB_FE:
22 return "dvb-frontend";
23 case MEDIA_INTF_T_DVB_DEMUX:
24 return "dvb-demux";
25 case MEDIA_INTF_T_DVB_DVR:
26 return "dvb-dvr";
27 case MEDIA_INTF_T_DVB_CA:
28 return "dvb-ca";
29 case MEDIA_INTF_T_DVB_NET:
30 return "dvb-net";
31 case MEDIA_INTF_T_V4L_VIDEO:
32 return "v4l-video";
33 case MEDIA_INTF_T_V4L_VBI:
34 return "v4l-vbi";
35 case MEDIA_INTF_T_V4L_RADIO:
36 return "v4l-radio";
37 case MEDIA_INTF_T_V4L_SUBDEV:
38 return "v4l-subdev";
39 case MEDIA_INTF_T_V4L_SWRADIO:
40 return "v4l-swradio";
41 case MEDIA_INTF_T_V4L_TOUCH:
42 return "v4l-touch";
43 default:
44 return "unknown-intf";
45 }
46};
47
48static inline const char *link_type_name(struct media_link *link)
49{
50 switch (link->flags & MEDIA_LNK_FL_LINK_TYPE) {
51 case MEDIA_LNK_FL_DATA_LINK:
52 return "data";
53 case MEDIA_LNK_FL_INTERFACE_LINK:
54 return "interface";
55 case MEDIA_LNK_FL_ANCILLARY_LINK:
56 return "ancillary";
57 default:
58 return "unknown";
59 }
60}
61
62__must_check int media_entity_enum_init(struct media_entity_enum *ent_enum,
63 struct media_device *mdev)
64{
65 int idx_max;
66
67 idx_max = ALIGN(mdev->entity_internal_idx_max + 1, BITS_PER_LONG);
68 ent_enum->bmap = bitmap_zalloc(idx_max, GFP_KERNEL);
69 if (!ent_enum->bmap)
70 return -ENOMEM;
71
72 ent_enum->idx_max = idx_max;
73
74 return 0;
75}
76EXPORT_SYMBOL_GPL(media_entity_enum_init);
77
78void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
79{
80 bitmap_free(ent_enum->bmap);
81}
82EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
83
84/**
85 * dev_dbg_obj - Prints in debug mode a change on some object
86 *
87 * @event_name: Name of the event to report. Could be __func__
88 * @gobj: Pointer to the object
89 *
90 * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
91 * won't produce any code.
92 */
93static void dev_dbg_obj(const char *event_name, struct media_gobj *gobj)
94{
95#if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
96 switch (media_type(gobj)) {
97 case MEDIA_GRAPH_ENTITY:
98 dev_dbg(gobj->mdev->dev,
99 "%s id %u: entity '%s'\n",
100 event_name, media_id(gobj),
101 gobj_to_entity(gobj)->name);
102 break;
103 case MEDIA_GRAPH_LINK:
104 {
105 struct media_link *link = gobj_to_link(gobj);
106
107 dev_dbg(gobj->mdev->dev,
108 "%s id %u: %s link id %u ==> id %u\n",
109 event_name, media_id(gobj), link_type_name(link),
110 media_id(link->gobj0),
111 media_id(link->gobj1));
112 break;
113 }
114 case MEDIA_GRAPH_PAD:
115 {
116 struct media_pad *pad = gobj_to_pad(gobj);
117
118 dev_dbg(gobj->mdev->dev,
119 "%s id %u: %s%spad '%s':%d\n",
120 event_name, media_id(gobj),
121 pad->flags & MEDIA_PAD_FL_SINK ? "sink " : "",
122 pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
123 pad->entity->name, pad->index);
124 break;
125 }
126 case MEDIA_GRAPH_INTF_DEVNODE:
127 {
128 struct media_interface *intf = gobj_to_intf(gobj);
129 struct media_intf_devnode *devnode = intf_to_devnode(intf);
130
131 dev_dbg(gobj->mdev->dev,
132 "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
133 event_name, media_id(gobj),
134 intf_type(intf),
135 devnode->major, devnode->minor);
136 break;
137 }
138 }
139#endif
140}
141
142void media_gobj_create(struct media_device *mdev,
143 enum media_gobj_type type,
144 struct media_gobj *gobj)
145{
146 BUG_ON(!mdev);
147
148 gobj->mdev = mdev;
149
150 /* Create a per-type unique object ID */
151 gobj->id = media_gobj_gen_id(type, ++mdev->id);
152
153 switch (type) {
154 case MEDIA_GRAPH_ENTITY:
155 list_add_tail(&gobj->list, &mdev->entities);
156 break;
157 case MEDIA_GRAPH_PAD:
158 list_add_tail(&gobj->list, &mdev->pads);
159 break;
160 case MEDIA_GRAPH_LINK:
161 list_add_tail(&gobj->list, &mdev->links);
162 break;
163 case MEDIA_GRAPH_INTF_DEVNODE:
164 list_add_tail(&gobj->list, &mdev->interfaces);
165 break;
166 }
167
168 mdev->topology_version++;
169
170 dev_dbg_obj(__func__, gobj);
171}
172
173void media_gobj_destroy(struct media_gobj *gobj)
174{
175 /* Do nothing if the object is not linked. */
176 if (gobj->mdev == NULL)
177 return;
178
179 dev_dbg_obj(__func__, gobj);
180
181 gobj->mdev->topology_version++;
182
183 /* Remove the object from mdev list */
184 list_del(&gobj->list);
185
186 gobj->mdev = NULL;
187}
188
189/*
190 * TODO: Get rid of this.
191 */
192#define MEDIA_ENTITY_MAX_PADS 512
193
194int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
195 struct media_pad *pads)
196{
197 struct media_device *mdev = entity->graph_obj.mdev;
198 struct media_pad *iter;
199 unsigned int i = 0;
200
201 if (num_pads >= MEDIA_ENTITY_MAX_PADS)
202 return -E2BIG;
203
204 entity->num_pads = num_pads;
205 entity->pads = pads;
206
207 if (mdev)
208 mutex_lock(&mdev->graph_mutex);
209
210 media_entity_for_each_pad(entity, iter) {
211 iter->entity = entity;
212 iter->index = i++;
213 if (mdev)
214 media_gobj_create(mdev, MEDIA_GRAPH_PAD,
215 &iter->graph_obj);
216 }
217
218 if (mdev)
219 mutex_unlock(&mdev->graph_mutex);
220
221 return 0;
222}
223EXPORT_SYMBOL_GPL(media_entity_pads_init);
224
225/* -----------------------------------------------------------------------------
226 * Graph traversal
227 */
228
229/*
230 * This function checks the interdependency inside the entity between @pad0
231 * and @pad1. If two pads are interdependent they are part of the same pipeline
232 * and enabling one of the pads means that the other pad will become "locked"
233 * and doesn't allow configuration changes.
234 *
235 * This function uses the &media_entity_operations.has_pad_interdep() operation
236 * to check the dependency inside the entity between @pad0 and @pad1. If the
237 * has_pad_interdep operation is not implemented, all pads of the entity are
238 * considered to be interdependent.
239 */
240static bool media_entity_has_pad_interdep(struct media_entity *entity,
241 unsigned int pad0, unsigned int pad1)
242{
243 if (pad0 >= entity->num_pads || pad1 >= entity->num_pads)
244 return false;
245
246 if (entity->pads[pad0].flags & entity->pads[pad1].flags &
247 (MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_SOURCE))
248 return false;
249
250 if (!entity->ops || !entity->ops->has_pad_interdep)
251 return true;
252
253 return entity->ops->has_pad_interdep(entity, pad0, pad1);
254}
255
256static struct media_entity *
257media_entity_other(struct media_entity *entity, struct media_link *link)
258{
259 if (link->source->entity == entity)
260 return link->sink->entity;
261 else
262 return link->source->entity;
263}
264
265/* push an entity to traversal stack */
266static void stack_push(struct media_graph *graph,
267 struct media_entity *entity)
268{
269 if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
270 WARN_ON(1);
271 return;
272 }
273 graph->top++;
274 graph->stack[graph->top].link = entity->links.next;
275 graph->stack[graph->top].entity = entity;
276}
277
278static struct media_entity *stack_pop(struct media_graph *graph)
279{
280 struct media_entity *entity;
281
282 entity = graph->stack[graph->top].entity;
283 graph->top--;
284
285 return entity;
286}
287
288#define link_top(en) ((en)->stack[(en)->top].link)
289#define stack_top(en) ((en)->stack[(en)->top].entity)
290
291/**
292 * media_graph_walk_init - Allocate resources for graph walk
293 * @graph: Media graph structure that will be used to walk the graph
294 * @mdev: Media device
295 *
296 * Reserve resources for graph walk in media device's current
297 * state. The memory must be released using
298 * media_graph_walk_free().
299 *
300 * Returns error on failure, zero on success.
301 */
302__must_check int media_graph_walk_init(
303 struct media_graph *graph, struct media_device *mdev)
304{
305 return media_entity_enum_init(&graph->ent_enum, mdev);
306}
307EXPORT_SYMBOL_GPL(media_graph_walk_init);
308
309/**
310 * media_graph_walk_cleanup - Release resources related to graph walking
311 * @graph: Media graph structure that was used to walk the graph
312 */
313void media_graph_walk_cleanup(struct media_graph *graph)
314{
315 media_entity_enum_cleanup(&graph->ent_enum);
316}
317EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
318
319void media_graph_walk_start(struct media_graph *graph,
320 struct media_entity *entity)
321{
322 media_entity_enum_zero(&graph->ent_enum);
323 media_entity_enum_set(&graph->ent_enum, entity);
324
325 graph->top = 0;
326 graph->stack[graph->top].entity = NULL;
327 stack_push(graph, entity);
328 dev_dbg(entity->graph_obj.mdev->dev,
329 "begin graph walk at '%s'\n", entity->name);
330}
331EXPORT_SYMBOL_GPL(media_graph_walk_start);
332
333static void media_graph_walk_iter(struct media_graph *graph)
334{
335 struct media_entity *entity = stack_top(graph);
336 struct media_link *link;
337 struct media_entity *next;
338
339 link = list_entry(link_top(graph), typeof(*link), list);
340
341 /* If the link is not a data link, don't follow it */
342 if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) != MEDIA_LNK_FL_DATA_LINK) {
343 link_top(graph) = link_top(graph)->next;
344 return;
345 }
346
347 /* The link is not enabled so we do not follow. */
348 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
349 link_top(graph) = link_top(graph)->next;
350 dev_dbg(entity->graph_obj.mdev->dev,
351 "walk: skipping disabled link '%s':%u -> '%s':%u\n",
352 link->source->entity->name, link->source->index,
353 link->sink->entity->name, link->sink->index);
354 return;
355 }
356
357 /* Get the entity at the other end of the link. */
358 next = media_entity_other(entity, link);
359
360 /* Has the entity already been visited? */
361 if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
362 link_top(graph) = link_top(graph)->next;
363 dev_dbg(entity->graph_obj.mdev->dev,
364 "walk: skipping entity '%s' (already seen)\n",
365 next->name);
366 return;
367 }
368
369 /* Push the new entity to stack and start over. */
370 link_top(graph) = link_top(graph)->next;
371 stack_push(graph, next);
372 dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
373 next->name);
374 lockdep_assert_held(&entity->graph_obj.mdev->graph_mutex);
375}
376
377struct media_entity *media_graph_walk_next(struct media_graph *graph)
378{
379 struct media_entity *entity;
380
381 if (stack_top(graph) == NULL)
382 return NULL;
383
384 /*
385 * Depth first search. Push entity to stack and continue from
386 * top of the stack until no more entities on the level can be
387 * found.
388 */
389 while (link_top(graph) != &stack_top(graph)->links)
390 media_graph_walk_iter(graph);
391
392 entity = stack_pop(graph);
393 dev_dbg(entity->graph_obj.mdev->dev,
394 "walk: returning entity '%s'\n", entity->name);
395
396 return entity;
397}
398EXPORT_SYMBOL_GPL(media_graph_walk_next);
399
400/* -----------------------------------------------------------------------------
401 * Pipeline management
402 */
403
404/*
405 * The pipeline traversal stack stores pads that are reached during graph
406 * traversal, with a list of links to be visited to continue the traversal.
407 * When a new pad is reached, an entry is pushed on the top of the stack and
408 * points to the incoming pad and the first link of the entity.
409 *
410 * To find further pads in the pipeline, the traversal algorithm follows
411 * internal pad dependencies in the entity, and then links in the graph. It
412 * does so by iterating over all links of the entity, and following enabled
413 * links that originate from a pad that is internally connected to the incoming
414 * pad, as reported by the media_entity_has_pad_interdep() function.
415 */
416
417/**
418 * struct media_pipeline_walk_entry - Entry in the pipeline traversal stack
419 *
420 * @pad: The media pad being visited
421 * @links: Links left to be visited
422 */
423struct media_pipeline_walk_entry {
424 struct media_pad *pad;
425 struct list_head *links;
426};
427
428/**
429 * struct media_pipeline_walk - State used by the media pipeline traversal
430 * algorithm
431 *
432 * @mdev: The media device
433 * @stack: Depth-first search stack
434 * @stack.size: Number of allocated entries in @stack.entries
435 * @stack.top: Index of the top stack entry (-1 if the stack is empty)
436 * @stack.entries: Stack entries
437 */
438struct media_pipeline_walk {
439 struct media_device *mdev;
440
441 struct {
442 unsigned int size;
443 int top;
444 struct media_pipeline_walk_entry *entries;
445 } stack;
446};
447
448#define MEDIA_PIPELINE_STACK_GROW_STEP 16
449
450static struct media_pipeline_walk_entry *
451media_pipeline_walk_top(struct media_pipeline_walk *walk)
452{
453 return &walk->stack.entries[walk->stack.top];
454}
455
456static bool media_pipeline_walk_empty(struct media_pipeline_walk *walk)
457{
458 return walk->stack.top == -1;
459}
460
461/* Increase the stack size by MEDIA_PIPELINE_STACK_GROW_STEP elements. */
462static int media_pipeline_walk_resize(struct media_pipeline_walk *walk)
463{
464 struct media_pipeline_walk_entry *entries;
465 unsigned int new_size;
466
467 /* Safety check, to avoid stack overflows in case of bugs. */
468 if (walk->stack.size >= 256)
469 return -E2BIG;
470
471 new_size = walk->stack.size + MEDIA_PIPELINE_STACK_GROW_STEP;
472
473 entries = krealloc(walk->stack.entries,
474 new_size * sizeof(*walk->stack.entries),
475 GFP_KERNEL);
476 if (!entries)
477 return -ENOMEM;
478
479 walk->stack.entries = entries;
480 walk->stack.size = new_size;
481
482 return 0;
483}
484
485/* Push a new entry on the stack. */
486static int media_pipeline_walk_push(struct media_pipeline_walk *walk,
487 struct media_pad *pad)
488{
489 struct media_pipeline_walk_entry *entry;
490 int ret;
491
492 if (walk->stack.top + 1 >= walk->stack.size) {
493 ret = media_pipeline_walk_resize(walk);
494 if (ret)
495 return ret;
496 }
497
498 walk->stack.top++;
499 entry = media_pipeline_walk_top(walk);
500 entry->pad = pad;
501 entry->links = pad->entity->links.next;
502
503 dev_dbg(walk->mdev->dev,
504 "media pipeline: pushed entry %u: '%s':%u\n",
505 walk->stack.top, pad->entity->name, pad->index);
506
507 return 0;
508}
509
510/*
511 * Move the top entry link cursor to the next link. If all links of the entry
512 * have been visited, pop the entry itself.
513 */
514static void media_pipeline_walk_pop(struct media_pipeline_walk *walk)
515{
516 struct media_pipeline_walk_entry *entry;
517
518 if (WARN_ON(walk->stack.top < 0))
519 return;
520
521 entry = media_pipeline_walk_top(walk);
522
523 if (entry->links->next == &entry->pad->entity->links) {
524 dev_dbg(walk->mdev->dev,
525 "media pipeline: entry %u has no more links, popping\n",
526 walk->stack.top);
527
528 walk->stack.top--;
529 return;
530 }
531
532 entry->links = entry->links->next;
533
534 dev_dbg(walk->mdev->dev,
535 "media pipeline: moved entry %u to next link\n",
536 walk->stack.top);
537}
538
539/* Free all memory allocated while walking the pipeline. */
540static void media_pipeline_walk_destroy(struct media_pipeline_walk *walk)
541{
542 kfree(walk->stack.entries);
543}
544
545/* Add a pad to the pipeline and push it to the stack. */
546static int media_pipeline_add_pad(struct media_pipeline *pipe,
547 struct media_pipeline_walk *walk,
548 struct media_pad *pad)
549{
550 struct media_pipeline_pad *ppad;
551
552 list_for_each_entry(ppad, &pipe->pads, list) {
553 if (ppad->pad == pad) {
554 dev_dbg(pad->graph_obj.mdev->dev,
555 "media pipeline: already contains pad '%s':%u\n",
556 pad->entity->name, pad->index);
557 return 0;
558 }
559 }
560
561 ppad = kzalloc(sizeof(*ppad), GFP_KERNEL);
562 if (!ppad)
563 return -ENOMEM;
564
565 ppad->pipe = pipe;
566 ppad->pad = pad;
567
568 list_add_tail(&ppad->list, &pipe->pads);
569
570 dev_dbg(pad->graph_obj.mdev->dev,
571 "media pipeline: added pad '%s':%u\n",
572 pad->entity->name, pad->index);
573
574 return media_pipeline_walk_push(walk, pad);
575}
576
577/* Explore the next link of the entity at the top of the stack. */
578static int media_pipeline_explore_next_link(struct media_pipeline *pipe,
579 struct media_pipeline_walk *walk)
580{
581 struct media_pipeline_walk_entry *entry = media_pipeline_walk_top(walk);
582 struct media_pad *pad;
583 struct media_link *link;
584 struct media_pad *local;
585 struct media_pad *remote;
586 int ret;
587
588 pad = entry->pad;
589 link = list_entry(entry->links, typeof(*link), list);
590 media_pipeline_walk_pop(walk);
591
592 dev_dbg(walk->mdev->dev,
593 "media pipeline: exploring link '%s':%u -> '%s':%u\n",
594 link->source->entity->name, link->source->index,
595 link->sink->entity->name, link->sink->index);
596
597 /* Skip links that are not enabled. */
598 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
599 dev_dbg(walk->mdev->dev,
600 "media pipeline: skipping link (disabled)\n");
601 return 0;
602 }
603
604 /* Get the local pad and remote pad. */
605 if (link->source->entity == pad->entity) {
606 local = link->source;
607 remote = link->sink;
608 } else {
609 local = link->sink;
610 remote = link->source;
611 }
612
613 /*
614 * Skip links that originate from a different pad than the incoming pad
615 * that is not connected internally in the entity to the incoming pad.
616 */
617 if (pad != local &&
618 !media_entity_has_pad_interdep(pad->entity, pad->index, local->index)) {
619 dev_dbg(walk->mdev->dev,
620 "media pipeline: skipping link (no route)\n");
621 return 0;
622 }
623
624 /*
625 * Add the local and remote pads of the link to the pipeline and push
626 * them to the stack, if they're not already present.
627 */
628 ret = media_pipeline_add_pad(pipe, walk, local);
629 if (ret)
630 return ret;
631
632 ret = media_pipeline_add_pad(pipe, walk, remote);
633 if (ret)
634 return ret;
635
636 return 0;
637}
638
639static void media_pipeline_cleanup(struct media_pipeline *pipe)
640{
641 while (!list_empty(&pipe->pads)) {
642 struct media_pipeline_pad *ppad;
643
644 ppad = list_first_entry(&pipe->pads, typeof(*ppad), list);
645 list_del(&ppad->list);
646 kfree(ppad);
647 }
648}
649
650static int media_pipeline_populate(struct media_pipeline *pipe,
651 struct media_pad *pad)
652{
653 struct media_pipeline_walk walk = { };
654 struct media_pipeline_pad *ppad;
655 int ret;
656
657 /*
658 * Populate the media pipeline by walking the media graph, starting
659 * from @pad.
660 */
661 INIT_LIST_HEAD(&pipe->pads);
662 pipe->mdev = pad->graph_obj.mdev;
663
664 walk.mdev = pipe->mdev;
665 walk.stack.top = -1;
666 ret = media_pipeline_add_pad(pipe, &walk, pad);
667 if (ret)
668 goto done;
669
670 /*
671 * Use a depth-first search algorithm: as long as the stack is not
672 * empty, explore the next link of the top entry. The
673 * media_pipeline_explore_next_link() function will either move to the
674 * next link, pop the entry if fully visited, or add new entries on
675 * top.
676 */
677 while (!media_pipeline_walk_empty(&walk)) {
678 ret = media_pipeline_explore_next_link(pipe, &walk);
679 if (ret)
680 goto done;
681 }
682
683 dev_dbg(pad->graph_obj.mdev->dev,
684 "media pipeline populated, found pads:\n");
685
686 list_for_each_entry(ppad, &pipe->pads, list)
687 dev_dbg(pad->graph_obj.mdev->dev, "- '%s':%u\n",
688 ppad->pad->entity->name, ppad->pad->index);
689
690 WARN_ON(walk.stack.top != -1);
691
692 ret = 0;
693
694done:
695 media_pipeline_walk_destroy(&walk);
696
697 if (ret)
698 media_pipeline_cleanup(pipe);
699
700 return ret;
701}
702
703__must_check int __media_pipeline_start(struct media_pad *pad,
704 struct media_pipeline *pipe)
705{
706 struct media_device *mdev = pad->entity->graph_obj.mdev;
707 struct media_pipeline_pad *err_ppad;
708 struct media_pipeline_pad *ppad;
709 int ret;
710
711 lockdep_assert_held(&mdev->graph_mutex);
712
713 /*
714 * If the entity is already part of a pipeline, that pipeline must
715 * be the same as the pipe given to media_pipeline_start().
716 */
717 if (WARN_ON(pad->pipe && pad->pipe != pipe))
718 return -EINVAL;
719
720 /*
721 * If the pipeline has already been started, it is guaranteed to be
722 * valid, so just increase the start count.
723 */
724 if (pipe->start_count) {
725 pipe->start_count++;
726 return 0;
727 }
728
729 /*
730 * Populate the pipeline. This populates the media_pipeline pads list
731 * with media_pipeline_pad instances for each pad found during graph
732 * walk.
733 */
734 ret = media_pipeline_populate(pipe, pad);
735 if (ret)
736 return ret;
737
738 /*
739 * Now that all the pads in the pipeline have been gathered, perform
740 * the validation steps.
741 */
742
743 list_for_each_entry(ppad, &pipe->pads, list) {
744 struct media_pad *pad = ppad->pad;
745 struct media_entity *entity = pad->entity;
746 bool has_enabled_link = false;
747 bool has_link = false;
748 struct media_link *link;
749
750 dev_dbg(mdev->dev, "Validating pad '%s':%u\n", pad->entity->name,
751 pad->index);
752
753 /*
754 * 1. Ensure that the pad doesn't already belong to a different
755 * pipeline.
756 */
757 if (pad->pipe) {
758 dev_dbg(mdev->dev, "Failed to start pipeline: pad '%s':%u busy\n",
759 pad->entity->name, pad->index);
760 ret = -EBUSY;
761 goto error;
762 }
763
764 /*
765 * 2. Validate all active links whose sink is the current pad.
766 * Validation of the source pads is performed in the context of
767 * the connected sink pad to avoid duplicating checks.
768 */
769 for_each_media_entity_data_link(entity, link) {
770 /* Skip links unrelated to the current pad. */
771 if (link->sink != pad && link->source != pad)
772 continue;
773
774 /* Record if the pad has links and enabled links. */
775 if (link->flags & MEDIA_LNK_FL_ENABLED)
776 has_enabled_link = true;
777 has_link = true;
778
779 /*
780 * Validate the link if it's enabled and has the
781 * current pad as its sink.
782 */
783 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
784 continue;
785
786 if (link->sink != pad)
787 continue;
788
789 if (!entity->ops || !entity->ops->link_validate)
790 continue;
791
792 ret = entity->ops->link_validate(link);
793 if (ret) {
794 dev_dbg(mdev->dev,
795 "Link '%s':%u -> '%s':%u failed validation: %d\n",
796 link->source->entity->name,
797 link->source->index,
798 link->sink->entity->name,
799 link->sink->index, ret);
800 goto error;
801 }
802
803 dev_dbg(mdev->dev,
804 "Link '%s':%u -> '%s':%u is valid\n",
805 link->source->entity->name,
806 link->source->index,
807 link->sink->entity->name,
808 link->sink->index);
809 }
810
811 /*
812 * 3. If the pad has the MEDIA_PAD_FL_MUST_CONNECT flag set,
813 * ensure that it has either no link or an enabled link.
814 */
815 if ((pad->flags & MEDIA_PAD_FL_MUST_CONNECT) && has_link &&
816 !has_enabled_link) {
817 dev_dbg(mdev->dev,
818 "Pad '%s':%u must be connected by an enabled link\n",
819 pad->entity->name, pad->index);
820 ret = -ENOLINK;
821 goto error;
822 }
823
824 /* Validation passed, store the pipe pointer in the pad. */
825 pad->pipe = pipe;
826 }
827
828 pipe->start_count++;
829
830 return 0;
831
832error:
833 /*
834 * Link validation on graph failed. We revert what we did and
835 * return the error.
836 */
837
838 list_for_each_entry(err_ppad, &pipe->pads, list) {
839 if (err_ppad == ppad)
840 break;
841
842 err_ppad->pad->pipe = NULL;
843 }
844
845 media_pipeline_cleanup(pipe);
846
847 return ret;
848}
849EXPORT_SYMBOL_GPL(__media_pipeline_start);
850
851__must_check int media_pipeline_start(struct media_pad *pad,
852 struct media_pipeline *pipe)
853{
854 struct media_device *mdev = pad->entity->graph_obj.mdev;
855 int ret;
856
857 mutex_lock(&mdev->graph_mutex);
858 ret = __media_pipeline_start(pad, pipe);
859 mutex_unlock(&mdev->graph_mutex);
860 return ret;
861}
862EXPORT_SYMBOL_GPL(media_pipeline_start);
863
864void __media_pipeline_stop(struct media_pad *pad)
865{
866 struct media_pipeline *pipe = pad->pipe;
867 struct media_pipeline_pad *ppad;
868
869 /*
870 * If the following check fails, the driver has performed an
871 * unbalanced call to media_pipeline_stop()
872 */
873 if (WARN_ON(!pipe))
874 return;
875
876 if (--pipe->start_count)
877 return;
878
879 list_for_each_entry(ppad, &pipe->pads, list)
880 ppad->pad->pipe = NULL;
881
882 media_pipeline_cleanup(pipe);
883
884 if (pipe->allocated)
885 kfree(pipe);
886}
887EXPORT_SYMBOL_GPL(__media_pipeline_stop);
888
889void media_pipeline_stop(struct media_pad *pad)
890{
891 struct media_device *mdev = pad->entity->graph_obj.mdev;
892
893 mutex_lock(&mdev->graph_mutex);
894 __media_pipeline_stop(pad);
895 mutex_unlock(&mdev->graph_mutex);
896}
897EXPORT_SYMBOL_GPL(media_pipeline_stop);
898
899__must_check int media_pipeline_alloc_start(struct media_pad *pad)
900{
901 struct media_device *mdev = pad->entity->graph_obj.mdev;
902 struct media_pipeline *new_pipe = NULL;
903 struct media_pipeline *pipe;
904 int ret;
905
906 mutex_lock(&mdev->graph_mutex);
907
908 /*
909 * Is the entity already part of a pipeline? If not, we need to allocate
910 * a pipe.
911 */
912 pipe = media_pad_pipeline(pad);
913 if (!pipe) {
914 new_pipe = kzalloc(sizeof(*new_pipe), GFP_KERNEL);
915 if (!new_pipe) {
916 ret = -ENOMEM;
917 goto out;
918 }
919
920 pipe = new_pipe;
921 pipe->allocated = true;
922 }
923
924 ret = __media_pipeline_start(pad, pipe);
925 if (ret)
926 kfree(new_pipe);
927
928out:
929 mutex_unlock(&mdev->graph_mutex);
930
931 return ret;
932}
933EXPORT_SYMBOL_GPL(media_pipeline_alloc_start);
934
935/* -----------------------------------------------------------------------------
936 * Links management
937 */
938
939static struct media_link *media_add_link(struct list_head *head)
940{
941 struct media_link *link;
942
943 link = kzalloc(sizeof(*link), GFP_KERNEL);
944 if (link == NULL)
945 return NULL;
946
947 list_add_tail(&link->list, head);
948
949 return link;
950}
951
952static void __media_entity_remove_link(struct media_entity *entity,
953 struct media_link *link)
954{
955 struct media_link *rlink, *tmp;
956 struct media_entity *remote;
957
958 /* Remove the reverse links for a data link. */
959 if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == MEDIA_LNK_FL_DATA_LINK) {
960 if (link->source->entity == entity)
961 remote = link->sink->entity;
962 else
963 remote = link->source->entity;
964
965 list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
966 if (rlink != link->reverse)
967 continue;
968
969 if (link->source->entity == entity)
970 remote->num_backlinks--;
971
972 /* Remove the remote link */
973 list_del(&rlink->list);
974 media_gobj_destroy(&rlink->graph_obj);
975 kfree(rlink);
976
977 if (--remote->num_links == 0)
978 break;
979 }
980 }
981
982 list_del(&link->list);
983 media_gobj_destroy(&link->graph_obj);
984 kfree(link);
985}
986
987int media_get_pad_index(struct media_entity *entity, bool is_sink,
988 enum media_pad_signal_type sig_type)
989{
990 int i;
991 bool pad_is_sink;
992
993 if (!entity)
994 return -EINVAL;
995
996 for (i = 0; i < entity->num_pads; i++) {
997 if (entity->pads[i].flags & MEDIA_PAD_FL_SINK)
998 pad_is_sink = true;
999 else if (entity->pads[i].flags & MEDIA_PAD_FL_SOURCE)
1000 pad_is_sink = false;
1001 else
1002 continue; /* This is an error! */
1003
1004 if (pad_is_sink != is_sink)
1005 continue;
1006 if (entity->pads[i].sig_type == sig_type)
1007 return i;
1008 }
1009 return -EINVAL;
1010}
1011EXPORT_SYMBOL_GPL(media_get_pad_index);
1012
1013int
1014media_create_pad_link(struct media_entity *source, u16 source_pad,
1015 struct media_entity *sink, u16 sink_pad, u32 flags)
1016{
1017 struct media_link *link;
1018 struct media_link *backlink;
1019
1020 if (WARN_ON(!source || !sink) ||
1021 WARN_ON(source_pad >= source->num_pads) ||
1022 WARN_ON(sink_pad >= sink->num_pads))
1023 return -EINVAL;
1024 if (WARN_ON(!(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE)))
1025 return -EINVAL;
1026 if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
1027 return -EINVAL;
1028
1029 link = media_add_link(&source->links);
1030 if (link == NULL)
1031 return -ENOMEM;
1032
1033 link->source = &source->pads[source_pad];
1034 link->sink = &sink->pads[sink_pad];
1035 link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
1036
1037 /* Initialize graph object embedded at the new link */
1038 media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
1039 &link->graph_obj);
1040
1041 /* Create the backlink. Backlinks are used to help graph traversal and
1042 * are not reported to userspace.
1043 */
1044 backlink = media_add_link(&sink->links);
1045 if (backlink == NULL) {
1046 __media_entity_remove_link(source, link);
1047 return -ENOMEM;
1048 }
1049
1050 backlink->source = &source->pads[source_pad];
1051 backlink->sink = &sink->pads[sink_pad];
1052 backlink->flags = flags;
1053 backlink->is_backlink = true;
1054
1055 /* Initialize graph object embedded at the new link */
1056 media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
1057 &backlink->graph_obj);
1058
1059 link->reverse = backlink;
1060 backlink->reverse = link;
1061
1062 sink->num_backlinks++;
1063 sink->num_links++;
1064 source->num_links++;
1065
1066 return 0;
1067}
1068EXPORT_SYMBOL_GPL(media_create_pad_link);
1069
1070int media_create_pad_links(const struct media_device *mdev,
1071 const u32 source_function,
1072 struct media_entity *source,
1073 const u16 source_pad,
1074 const u32 sink_function,
1075 struct media_entity *sink,
1076 const u16 sink_pad,
1077 u32 flags,
1078 const bool allow_both_undefined)
1079{
1080 struct media_entity *entity;
1081 unsigned function;
1082 int ret;
1083
1084 /* Trivial case: 1:1 relation */
1085 if (source && sink)
1086 return media_create_pad_link(source, source_pad,
1087 sink, sink_pad, flags);
1088
1089 /* Worse case scenario: n:n relation */
1090 if (!source && !sink) {
1091 if (!allow_both_undefined)
1092 return 0;
1093 media_device_for_each_entity(source, mdev) {
1094 if (source->function != source_function)
1095 continue;
1096 media_device_for_each_entity(sink, mdev) {
1097 if (sink->function != sink_function)
1098 continue;
1099 ret = media_create_pad_link(source, source_pad,
1100 sink, sink_pad,
1101 flags);
1102 if (ret)
1103 return ret;
1104 flags &= ~(MEDIA_LNK_FL_ENABLED |
1105 MEDIA_LNK_FL_IMMUTABLE);
1106 }
1107 }
1108 return 0;
1109 }
1110
1111 /* Handle 1:n and n:1 cases */
1112 if (source)
1113 function = sink_function;
1114 else
1115 function = source_function;
1116
1117 media_device_for_each_entity(entity, mdev) {
1118 if (entity->function != function)
1119 continue;
1120
1121 if (source)
1122 ret = media_create_pad_link(source, source_pad,
1123 entity, sink_pad, flags);
1124 else
1125 ret = media_create_pad_link(entity, source_pad,
1126 sink, sink_pad, flags);
1127 if (ret)
1128 return ret;
1129 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
1130 }
1131 return 0;
1132}
1133EXPORT_SYMBOL_GPL(media_create_pad_links);
1134
1135void __media_entity_remove_links(struct media_entity *entity)
1136{
1137 struct media_link *link, *tmp;
1138
1139 list_for_each_entry_safe(link, tmp, &entity->links, list)
1140 __media_entity_remove_link(entity, link);
1141
1142 entity->num_links = 0;
1143 entity->num_backlinks = 0;
1144}
1145EXPORT_SYMBOL_GPL(__media_entity_remove_links);
1146
1147void media_entity_remove_links(struct media_entity *entity)
1148{
1149 struct media_device *mdev = entity->graph_obj.mdev;
1150
1151 /* Do nothing if the entity is not registered. */
1152 if (mdev == NULL)
1153 return;
1154
1155 mutex_lock(&mdev->graph_mutex);
1156 __media_entity_remove_links(entity);
1157 mutex_unlock(&mdev->graph_mutex);
1158}
1159EXPORT_SYMBOL_GPL(media_entity_remove_links);
1160
1161static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
1162{
1163 int ret;
1164
1165 /* Notify both entities. */
1166 ret = media_entity_call(link->source->entity, link_setup,
1167 link->source, link->sink, flags);
1168 if (ret < 0 && ret != -ENOIOCTLCMD)
1169 return ret;
1170
1171 ret = media_entity_call(link->sink->entity, link_setup,
1172 link->sink, link->source, flags);
1173 if (ret < 0 && ret != -ENOIOCTLCMD) {
1174 media_entity_call(link->source->entity, link_setup,
1175 link->source, link->sink, link->flags);
1176 return ret;
1177 }
1178
1179 link->flags = flags;
1180 link->reverse->flags = link->flags;
1181
1182 return 0;
1183}
1184
1185int __media_entity_setup_link(struct media_link *link, u32 flags)
1186{
1187 const u32 mask = MEDIA_LNK_FL_ENABLED;
1188 struct media_device *mdev;
1189 struct media_pad *source, *sink;
1190 int ret = -EBUSY;
1191
1192 if (link == NULL)
1193 return -EINVAL;
1194
1195 /* The non-modifiable link flags must not be modified. */
1196 if ((link->flags & ~mask) != (flags & ~mask))
1197 return -EINVAL;
1198
1199 if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
1200 return link->flags == flags ? 0 : -EINVAL;
1201
1202 if (link->flags == flags)
1203 return 0;
1204
1205 source = link->source;
1206 sink = link->sink;
1207
1208 if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
1209 (media_pad_is_streaming(source) || media_pad_is_streaming(sink)))
1210 return -EBUSY;
1211
1212 mdev = source->graph_obj.mdev;
1213
1214 if (mdev->ops && mdev->ops->link_notify) {
1215 ret = mdev->ops->link_notify(link, flags,
1216 MEDIA_DEV_NOTIFY_PRE_LINK_CH);
1217 if (ret < 0)
1218 return ret;
1219 }
1220
1221 ret = __media_entity_setup_link_notify(link, flags);
1222
1223 if (mdev->ops && mdev->ops->link_notify)
1224 mdev->ops->link_notify(link, flags,
1225 MEDIA_DEV_NOTIFY_POST_LINK_CH);
1226
1227 return ret;
1228}
1229EXPORT_SYMBOL_GPL(__media_entity_setup_link);
1230
1231int media_entity_setup_link(struct media_link *link, u32 flags)
1232{
1233 int ret;
1234
1235 mutex_lock(&link->graph_obj.mdev->graph_mutex);
1236 ret = __media_entity_setup_link(link, flags);
1237 mutex_unlock(&link->graph_obj.mdev->graph_mutex);
1238
1239 return ret;
1240}
1241EXPORT_SYMBOL_GPL(media_entity_setup_link);
1242
1243struct media_link *
1244media_entity_find_link(struct media_pad *source, struct media_pad *sink)
1245{
1246 struct media_link *link;
1247
1248 for_each_media_entity_data_link(source->entity, link) {
1249 if (link->source->entity == source->entity &&
1250 link->source->index == source->index &&
1251 link->sink->entity == sink->entity &&
1252 link->sink->index == sink->index)
1253 return link;
1254 }
1255
1256 return NULL;
1257}
1258EXPORT_SYMBOL_GPL(media_entity_find_link);
1259
1260struct media_pad *media_pad_remote_pad_first(const struct media_pad *pad)
1261{
1262 struct media_link *link;
1263
1264 for_each_media_entity_data_link(pad->entity, link) {
1265 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
1266 continue;
1267
1268 if (link->source == pad)
1269 return link->sink;
1270
1271 if (link->sink == pad)
1272 return link->source;
1273 }
1274
1275 return NULL;
1276
1277}
1278EXPORT_SYMBOL_GPL(media_pad_remote_pad_first);
1279
1280struct media_pad *
1281media_entity_remote_pad_unique(const struct media_entity *entity,
1282 unsigned int type)
1283{
1284 struct media_pad *pad = NULL;
1285 struct media_link *link;
1286
1287 list_for_each_entry(link, &entity->links, list) {
1288 struct media_pad *local_pad;
1289 struct media_pad *remote_pad;
1290
1291 if (((link->flags & MEDIA_LNK_FL_LINK_TYPE) !=
1292 MEDIA_LNK_FL_DATA_LINK) ||
1293 !(link->flags & MEDIA_LNK_FL_ENABLED))
1294 continue;
1295
1296 if (type == MEDIA_PAD_FL_SOURCE) {
1297 local_pad = link->sink;
1298 remote_pad = link->source;
1299 } else {
1300 local_pad = link->source;
1301 remote_pad = link->sink;
1302 }
1303
1304 if (local_pad->entity == entity) {
1305 if (pad)
1306 return ERR_PTR(-ENOTUNIQ);
1307
1308 pad = remote_pad;
1309 }
1310 }
1311
1312 if (!pad)
1313 return ERR_PTR(-ENOLINK);
1314
1315 return pad;
1316}
1317EXPORT_SYMBOL_GPL(media_entity_remote_pad_unique);
1318
1319struct media_pad *media_pad_remote_pad_unique(const struct media_pad *pad)
1320{
1321 struct media_pad *found_pad = NULL;
1322 struct media_link *link;
1323
1324 list_for_each_entry(link, &pad->entity->links, list) {
1325 struct media_pad *remote_pad;
1326
1327 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
1328 continue;
1329
1330 if (link->sink == pad)
1331 remote_pad = link->source;
1332 else if (link->source == pad)
1333 remote_pad = link->sink;
1334 else
1335 continue;
1336
1337 if (found_pad)
1338 return ERR_PTR(-ENOTUNIQ);
1339
1340 found_pad = remote_pad;
1341 }
1342
1343 if (!found_pad)
1344 return ERR_PTR(-ENOLINK);
1345
1346 return found_pad;
1347}
1348EXPORT_SYMBOL_GPL(media_pad_remote_pad_unique);
1349
1350int media_entity_get_fwnode_pad(struct media_entity *entity,
1351 struct fwnode_handle *fwnode,
1352 unsigned long direction_flags)
1353{
1354 struct fwnode_endpoint endpoint;
1355 unsigned int i;
1356 int ret;
1357
1358 if (!entity->ops || !entity->ops->get_fwnode_pad) {
1359 for (i = 0; i < entity->num_pads; i++) {
1360 if (entity->pads[i].flags & direction_flags)
1361 return i;
1362 }
1363
1364 return -ENXIO;
1365 }
1366
1367 ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
1368 if (ret)
1369 return ret;
1370
1371 ret = entity->ops->get_fwnode_pad(entity, &endpoint);
1372 if (ret < 0)
1373 return ret;
1374
1375 if (ret >= entity->num_pads)
1376 return -ENXIO;
1377
1378 if (!(entity->pads[ret].flags & direction_flags))
1379 return -ENXIO;
1380
1381 return ret;
1382}
1383EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
1384
1385struct media_pipeline *media_entity_pipeline(struct media_entity *entity)
1386{
1387 struct media_pad *pad;
1388
1389 media_entity_for_each_pad(entity, pad) {
1390 if (pad->pipe)
1391 return pad->pipe;
1392 }
1393
1394 return NULL;
1395}
1396EXPORT_SYMBOL_GPL(media_entity_pipeline);
1397
1398struct media_pipeline *media_pad_pipeline(struct media_pad *pad)
1399{
1400 return pad->pipe;
1401}
1402EXPORT_SYMBOL_GPL(media_pad_pipeline);
1403
1404static void media_interface_init(struct media_device *mdev,
1405 struct media_interface *intf,
1406 u32 gobj_type,
1407 u32 intf_type, u32 flags)
1408{
1409 intf->type = intf_type;
1410 intf->flags = flags;
1411 INIT_LIST_HEAD(&intf->links);
1412
1413 media_gobj_create(mdev, gobj_type, &intf->graph_obj);
1414}
1415
1416/* Functions related to the media interface via device nodes */
1417
1418struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
1419 u32 type, u32 flags,
1420 u32 major, u32 minor)
1421{
1422 struct media_intf_devnode *devnode;
1423
1424 devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
1425 if (!devnode)
1426 return NULL;
1427
1428 devnode->major = major;
1429 devnode->minor = minor;
1430
1431 media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
1432 type, flags);
1433
1434 return devnode;
1435}
1436EXPORT_SYMBOL_GPL(media_devnode_create);
1437
1438void media_devnode_remove(struct media_intf_devnode *devnode)
1439{
1440 media_remove_intf_links(&devnode->intf);
1441 media_gobj_destroy(&devnode->intf.graph_obj);
1442 kfree(devnode);
1443}
1444EXPORT_SYMBOL_GPL(media_devnode_remove);
1445
1446struct media_link *media_create_intf_link(struct media_entity *entity,
1447 struct media_interface *intf,
1448 u32 flags)
1449{
1450 struct media_link *link;
1451
1452 link = media_add_link(&intf->links);
1453 if (link == NULL)
1454 return NULL;
1455
1456 link->intf = intf;
1457 link->entity = entity;
1458 link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
1459
1460 /* Initialize graph object embedded at the new link */
1461 media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
1462 &link->graph_obj);
1463
1464 return link;
1465}
1466EXPORT_SYMBOL_GPL(media_create_intf_link);
1467
1468void __media_remove_intf_link(struct media_link *link)
1469{
1470 list_del(&link->list);
1471 media_gobj_destroy(&link->graph_obj);
1472 kfree(link);
1473}
1474EXPORT_SYMBOL_GPL(__media_remove_intf_link);
1475
1476void media_remove_intf_link(struct media_link *link)
1477{
1478 struct media_device *mdev = link->graph_obj.mdev;
1479
1480 /* Do nothing if the intf is not registered. */
1481 if (mdev == NULL)
1482 return;
1483
1484 mutex_lock(&mdev->graph_mutex);
1485 __media_remove_intf_link(link);
1486 mutex_unlock(&mdev->graph_mutex);
1487}
1488EXPORT_SYMBOL_GPL(media_remove_intf_link);
1489
1490void __media_remove_intf_links(struct media_interface *intf)
1491{
1492 struct media_link *link, *tmp;
1493
1494 list_for_each_entry_safe(link, tmp, &intf->links, list)
1495 __media_remove_intf_link(link);
1496
1497}
1498EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1499
1500void media_remove_intf_links(struct media_interface *intf)
1501{
1502 struct media_device *mdev = intf->graph_obj.mdev;
1503
1504 /* Do nothing if the intf is not registered. */
1505 if (mdev == NULL)
1506 return;
1507
1508 mutex_lock(&mdev->graph_mutex);
1509 __media_remove_intf_links(intf);
1510 mutex_unlock(&mdev->graph_mutex);
1511}
1512EXPORT_SYMBOL_GPL(media_remove_intf_links);
1513
1514struct media_link *media_create_ancillary_link(struct media_entity *primary,
1515 struct media_entity *ancillary)
1516{
1517 struct media_link *link;
1518
1519 link = media_add_link(&primary->links);
1520 if (!link)
1521 return ERR_PTR(-ENOMEM);
1522
1523 link->gobj0 = &primary->graph_obj;
1524 link->gobj1 = &ancillary->graph_obj;
1525 link->flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED |
1526 MEDIA_LNK_FL_ANCILLARY_LINK;
1527
1528 /* Initialize graph object embedded in the new link */
1529 media_gobj_create(primary->graph_obj.mdev, MEDIA_GRAPH_LINK,
1530 &link->graph_obj);
1531
1532 return link;
1533}
1534EXPORT_SYMBOL_GPL(media_create_ancillary_link);
1535
1536struct media_link *__media_entity_next_link(struct media_entity *entity,
1537 struct media_link *link,
1538 unsigned long link_type)
1539{
1540 link = link ? list_next_entry(link, list)
1541 : list_first_entry(&entity->links, typeof(*link), list);
1542
1543 list_for_each_entry_from(link, &entity->links, list)
1544 if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == link_type)
1545 return link;
1546
1547 return NULL;
1548}
1549EXPORT_SYMBOL_GPL(__media_entity_next_link);