xref: /openbmc/linux/drivers/media/mc/mc-entity.c (revision 465191d6)
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/property.h>
13 #include <linux/slab.h>
14 #include <media/media-entity.h>
15 #include <media/media-device.h>
16 
17 static inline const char *intf_type(struct media_interface *intf)
18 {
19 	switch (intf->type) {
20 	case MEDIA_INTF_T_DVB_FE:
21 		return "dvb-frontend";
22 	case MEDIA_INTF_T_DVB_DEMUX:
23 		return "dvb-demux";
24 	case MEDIA_INTF_T_DVB_DVR:
25 		return "dvb-dvr";
26 	case MEDIA_INTF_T_DVB_CA:
27 		return  "dvb-ca";
28 	case MEDIA_INTF_T_DVB_NET:
29 		return "dvb-net";
30 	case MEDIA_INTF_T_V4L_VIDEO:
31 		return "v4l-video";
32 	case MEDIA_INTF_T_V4L_VBI:
33 		return "v4l-vbi";
34 	case MEDIA_INTF_T_V4L_RADIO:
35 		return "v4l-radio";
36 	case MEDIA_INTF_T_V4L_SUBDEV:
37 		return "v4l-subdev";
38 	case MEDIA_INTF_T_V4L_SWRADIO:
39 		return "v4l-swradio";
40 	case MEDIA_INTF_T_V4L_TOUCH:
41 		return "v4l-touch";
42 	default:
43 		return "unknown-intf";
44 	}
45 };
46 
47 static inline const char *link_type_name(struct media_link *link)
48 {
49 	switch (link->flags & MEDIA_LNK_FL_LINK_TYPE) {
50 	case MEDIA_LNK_FL_DATA_LINK:
51 		return "data";
52 	case MEDIA_LNK_FL_INTERFACE_LINK:
53 		return "interface";
54 	case MEDIA_LNK_FL_ANCILLARY_LINK:
55 		return "ancillary";
56 	default:
57 		return "unknown";
58 	}
59 }
60 
61 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
62 					  int idx_max)
63 {
64 	idx_max = ALIGN(idx_max, BITS_PER_LONG);
65 	ent_enum->bmap = bitmap_zalloc(idx_max, GFP_KERNEL);
66 	if (!ent_enum->bmap)
67 		return -ENOMEM;
68 
69 	ent_enum->idx_max = idx_max;
70 
71 	return 0;
72 }
73 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
74 
75 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
76 {
77 	bitmap_free(ent_enum->bmap);
78 }
79 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
80 
81 /**
82  *  dev_dbg_obj - Prints in debug mode a change on some object
83  *
84  * @event_name:	Name of the event to report. Could be __func__
85  * @gobj:	Pointer to the object
86  *
87  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
88  * won't produce any code.
89  */
90 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
91 {
92 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
93 	switch (media_type(gobj)) {
94 	case MEDIA_GRAPH_ENTITY:
95 		dev_dbg(gobj->mdev->dev,
96 			"%s id %u: entity '%s'\n",
97 			event_name, media_id(gobj),
98 			gobj_to_entity(gobj)->name);
99 		break;
100 	case MEDIA_GRAPH_LINK:
101 	{
102 		struct media_link *link = gobj_to_link(gobj);
103 
104 		dev_dbg(gobj->mdev->dev,
105 			"%s id %u: %s link id %u ==> id %u\n",
106 			event_name, media_id(gobj), link_type_name(link),
107 			media_id(link->gobj0),
108 			media_id(link->gobj1));
109 		break;
110 	}
111 	case MEDIA_GRAPH_PAD:
112 	{
113 		struct media_pad *pad = gobj_to_pad(gobj);
114 
115 		dev_dbg(gobj->mdev->dev,
116 			"%s id %u: %s%spad '%s':%d\n",
117 			event_name, media_id(gobj),
118 			pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
119 			pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
120 			pad->entity->name, pad->index);
121 		break;
122 	}
123 	case MEDIA_GRAPH_INTF_DEVNODE:
124 	{
125 		struct media_interface *intf = gobj_to_intf(gobj);
126 		struct media_intf_devnode *devnode = intf_to_devnode(intf);
127 
128 		dev_dbg(gobj->mdev->dev,
129 			"%s id %u: intf_devnode %s - major: %d, minor: %d\n",
130 			event_name, media_id(gobj),
131 			intf_type(intf),
132 			devnode->major, devnode->minor);
133 		break;
134 	}
135 	}
136 #endif
137 }
138 
139 void media_gobj_create(struct media_device *mdev,
140 			   enum media_gobj_type type,
141 			   struct media_gobj *gobj)
142 {
143 	BUG_ON(!mdev);
144 
145 	gobj->mdev = mdev;
146 
147 	/* Create a per-type unique object ID */
148 	gobj->id = media_gobj_gen_id(type, ++mdev->id);
149 
150 	switch (type) {
151 	case MEDIA_GRAPH_ENTITY:
152 		list_add_tail(&gobj->list, &mdev->entities);
153 		break;
154 	case MEDIA_GRAPH_PAD:
155 		list_add_tail(&gobj->list, &mdev->pads);
156 		break;
157 	case MEDIA_GRAPH_LINK:
158 		list_add_tail(&gobj->list, &mdev->links);
159 		break;
160 	case MEDIA_GRAPH_INTF_DEVNODE:
161 		list_add_tail(&gobj->list, &mdev->interfaces);
162 		break;
163 	}
164 
165 	mdev->topology_version++;
166 
167 	dev_dbg_obj(__func__, gobj);
168 }
169 
170 void media_gobj_destroy(struct media_gobj *gobj)
171 {
172 	/* Do nothing if the object is not linked. */
173 	if (gobj->mdev == NULL)
174 		return;
175 
176 	dev_dbg_obj(__func__, gobj);
177 
178 	gobj->mdev->topology_version++;
179 
180 	/* Remove the object from mdev list */
181 	list_del(&gobj->list);
182 
183 	gobj->mdev = NULL;
184 }
185 
186 /*
187  * TODO: Get rid of this.
188  */
189 #define MEDIA_ENTITY_MAX_PADS		512
190 
191 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
192 			   struct media_pad *pads)
193 {
194 	struct media_device *mdev = entity->graph_obj.mdev;
195 	unsigned int i;
196 
197 	if (num_pads >= MEDIA_ENTITY_MAX_PADS)
198 		return -E2BIG;
199 
200 	entity->num_pads = num_pads;
201 	entity->pads = pads;
202 
203 	if (mdev)
204 		mutex_lock(&mdev->graph_mutex);
205 
206 	for (i = 0; i < num_pads; i++) {
207 		pads[i].entity = entity;
208 		pads[i].index = i;
209 		if (mdev)
210 			media_gobj_create(mdev, MEDIA_GRAPH_PAD,
211 					&entity->pads[i].graph_obj);
212 	}
213 
214 	if (mdev)
215 		mutex_unlock(&mdev->graph_mutex);
216 
217 	return 0;
218 }
219 EXPORT_SYMBOL_GPL(media_entity_pads_init);
220 
221 /* -----------------------------------------------------------------------------
222  * Graph traversal
223  */
224 
225 static struct media_entity *
226 media_entity_other(struct media_entity *entity, struct media_link *link)
227 {
228 	if (link->source->entity == entity)
229 		return link->sink->entity;
230 	else
231 		return link->source->entity;
232 }
233 
234 /* push an entity to traversal stack */
235 static void stack_push(struct media_graph *graph,
236 		       struct media_entity *entity)
237 {
238 	if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
239 		WARN_ON(1);
240 		return;
241 	}
242 	graph->top++;
243 	graph->stack[graph->top].link = entity->links.next;
244 	graph->stack[graph->top].entity = entity;
245 }
246 
247 static struct media_entity *stack_pop(struct media_graph *graph)
248 {
249 	struct media_entity *entity;
250 
251 	entity = graph->stack[graph->top].entity;
252 	graph->top--;
253 
254 	return entity;
255 }
256 
257 #define link_top(en)	((en)->stack[(en)->top].link)
258 #define stack_top(en)	((en)->stack[(en)->top].entity)
259 
260 /**
261  * media_graph_walk_init - Allocate resources for graph walk
262  * @graph: Media graph structure that will be used to walk the graph
263  * @mdev: Media device
264  *
265  * Reserve resources for graph walk in media device's current
266  * state. The memory must be released using
267  * media_graph_walk_free().
268  *
269  * Returns error on failure, zero on success.
270  */
271 __must_check int media_graph_walk_init(
272 	struct media_graph *graph, struct media_device *mdev)
273 {
274 	return media_entity_enum_init(&graph->ent_enum, mdev);
275 }
276 EXPORT_SYMBOL_GPL(media_graph_walk_init);
277 
278 /**
279  * media_graph_walk_cleanup - Release resources related to graph walking
280  * @graph: Media graph structure that was used to walk the graph
281  */
282 void media_graph_walk_cleanup(struct media_graph *graph)
283 {
284 	media_entity_enum_cleanup(&graph->ent_enum);
285 }
286 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
287 
288 void media_graph_walk_start(struct media_graph *graph,
289 			    struct media_entity *entity)
290 {
291 	media_entity_enum_zero(&graph->ent_enum);
292 	media_entity_enum_set(&graph->ent_enum, entity);
293 
294 	graph->top = 0;
295 	graph->stack[graph->top].entity = NULL;
296 	stack_push(graph, entity);
297 	dev_dbg(entity->graph_obj.mdev->dev,
298 		"begin graph walk at '%s'\n", entity->name);
299 }
300 EXPORT_SYMBOL_GPL(media_graph_walk_start);
301 
302 static void media_graph_walk_iter(struct media_graph *graph)
303 {
304 	struct media_entity *entity = stack_top(graph);
305 	struct media_link *link;
306 	struct media_entity *next;
307 
308 	link = list_entry(link_top(graph), typeof(*link), list);
309 
310 	/* If the link is not a data link, don't follow it */
311 	if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) != MEDIA_LNK_FL_DATA_LINK) {
312 		link_top(graph) = link_top(graph)->next;
313 		return;
314 	}
315 
316 	/* The link is not enabled so we do not follow. */
317 	if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
318 		link_top(graph) = link_top(graph)->next;
319 		dev_dbg(entity->graph_obj.mdev->dev,
320 			"walk: skipping disabled link '%s':%u -> '%s':%u\n",
321 			link->source->entity->name, link->source->index,
322 			link->sink->entity->name, link->sink->index);
323 		return;
324 	}
325 
326 	/* Get the entity at the other end of the link. */
327 	next = media_entity_other(entity, link);
328 
329 	/* Has the entity already been visited? */
330 	if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
331 		link_top(graph) = link_top(graph)->next;
332 		dev_dbg(entity->graph_obj.mdev->dev,
333 			"walk: skipping entity '%s' (already seen)\n",
334 			next->name);
335 		return;
336 	}
337 
338 	/* Push the new entity to stack and start over. */
339 	link_top(graph) = link_top(graph)->next;
340 	stack_push(graph, next);
341 	dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
342 		next->name);
343 	lockdep_assert_held(&entity->graph_obj.mdev->graph_mutex);
344 }
345 
346 struct media_entity *media_graph_walk_next(struct media_graph *graph)
347 {
348 	struct media_entity *entity;
349 
350 	if (stack_top(graph) == NULL)
351 		return NULL;
352 
353 	/*
354 	 * Depth first search. Push entity to stack and continue from
355 	 * top of the stack until no more entities on the level can be
356 	 * found.
357 	 */
358 	while (link_top(graph) != &stack_top(graph)->links)
359 		media_graph_walk_iter(graph);
360 
361 	entity = stack_pop(graph);
362 	dev_dbg(entity->graph_obj.mdev->dev,
363 		"walk: returning entity '%s'\n", entity->name);
364 
365 	return entity;
366 }
367 EXPORT_SYMBOL_GPL(media_graph_walk_next);
368 
369 int media_entity_get_fwnode_pad(struct media_entity *entity,
370 				struct fwnode_handle *fwnode,
371 				unsigned long direction_flags)
372 {
373 	struct fwnode_endpoint endpoint;
374 	unsigned int i;
375 	int ret;
376 
377 	if (!entity->ops || !entity->ops->get_fwnode_pad) {
378 		for (i = 0; i < entity->num_pads; i++) {
379 			if (entity->pads[i].flags & direction_flags)
380 				return i;
381 		}
382 
383 		return -ENXIO;
384 	}
385 
386 	ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
387 	if (ret)
388 		return ret;
389 
390 	ret = entity->ops->get_fwnode_pad(entity, &endpoint);
391 	if (ret < 0)
392 		return ret;
393 
394 	if (ret >= entity->num_pads)
395 		return -ENXIO;
396 
397 	if (!(entity->pads[ret].flags & direction_flags))
398 		return -ENXIO;
399 
400 	return ret;
401 }
402 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
403 
404 /* -----------------------------------------------------------------------------
405  * Pipeline management
406  */
407 
408 __must_check int __media_pipeline_start(struct media_entity *entity,
409 					struct media_pipeline *pipe)
410 {
411 	struct media_device *mdev = entity->graph_obj.mdev;
412 	struct media_graph *graph = &pipe->graph;
413 	struct media_entity *entity_err = entity;
414 	struct media_link *link;
415 	int ret;
416 
417 	if (pipe->streaming_count) {
418 		pipe->streaming_count++;
419 		return 0;
420 	}
421 
422 	ret = media_graph_walk_init(&pipe->graph, mdev);
423 	if (ret)
424 		return ret;
425 
426 	media_graph_walk_start(&pipe->graph, entity);
427 
428 	while ((entity = media_graph_walk_next(graph))) {
429 		DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
430 		DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
431 
432 		if (entity->pipe && entity->pipe != pipe) {
433 			pr_err("Pipe active for %s. Can't start for %s\n",
434 				entity->name,
435 				entity_err->name);
436 			ret = -EBUSY;
437 			goto error;
438 		}
439 
440 		/* Already streaming --- no need to check. */
441 		if (entity->pipe)
442 			continue;
443 
444 		entity->pipe = pipe;
445 
446 		if (!entity->ops || !entity->ops->link_validate)
447 			continue;
448 
449 		bitmap_zero(active, entity->num_pads);
450 		bitmap_fill(has_no_links, entity->num_pads);
451 
452 		list_for_each_entry(link, &entity->links, list) {
453 			struct media_pad *pad = link->sink->entity == entity
454 						? link->sink : link->source;
455 
456 			/* Mark that a pad is connected by a link. */
457 			bitmap_clear(has_no_links, pad->index, 1);
458 
459 			/*
460 			 * Pads that either do not need to connect or
461 			 * are connected through an enabled link are
462 			 * fine.
463 			 */
464 			if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
465 			    link->flags & MEDIA_LNK_FL_ENABLED)
466 				bitmap_set(active, pad->index, 1);
467 
468 			/*
469 			 * Link validation will only take place for
470 			 * sink ends of the link that are enabled.
471 			 */
472 			if (link->sink != pad ||
473 			    !(link->flags & MEDIA_LNK_FL_ENABLED))
474 				continue;
475 
476 			ret = entity->ops->link_validate(link);
477 			if (ret < 0 && ret != -ENOIOCTLCMD) {
478 				dev_dbg(entity->graph_obj.mdev->dev,
479 					"link validation failed for '%s':%u -> '%s':%u, error %d\n",
480 					link->source->entity->name,
481 					link->source->index,
482 					entity->name, link->sink->index, ret);
483 				goto error;
484 			}
485 		}
486 
487 		/* Either no links or validated links are fine. */
488 		bitmap_or(active, active, has_no_links, entity->num_pads);
489 
490 		if (!bitmap_full(active, entity->num_pads)) {
491 			ret = -ENOLINK;
492 			dev_dbg(entity->graph_obj.mdev->dev,
493 				"'%s':%u must be connected by an enabled link\n",
494 				entity->name,
495 				(unsigned)find_first_zero_bit(
496 					active, entity->num_pads));
497 			goto error;
498 		}
499 	}
500 
501 	pipe->streaming_count++;
502 
503 	return 0;
504 
505 error:
506 	/*
507 	 * Link validation on graph failed. We revert what we did and
508 	 * return the error.
509 	 */
510 	media_graph_walk_start(graph, entity_err);
511 
512 	while ((entity_err = media_graph_walk_next(graph))) {
513 		entity_err->pipe = NULL;
514 
515 		/*
516 		 * We haven't started entities further than this so we quit
517 		 * here.
518 		 */
519 		if (entity_err == entity)
520 			break;
521 	}
522 
523 	media_graph_walk_cleanup(graph);
524 
525 	return ret;
526 }
527 EXPORT_SYMBOL_GPL(__media_pipeline_start);
528 
529 __must_check int media_pipeline_start(struct media_entity *entity,
530 				      struct media_pipeline *pipe)
531 {
532 	struct media_device *mdev = entity->graph_obj.mdev;
533 	int ret;
534 
535 	mutex_lock(&mdev->graph_mutex);
536 	ret = __media_pipeline_start(entity, pipe);
537 	mutex_unlock(&mdev->graph_mutex);
538 	return ret;
539 }
540 EXPORT_SYMBOL_GPL(media_pipeline_start);
541 
542 void __media_pipeline_stop(struct media_entity *entity)
543 {
544 	struct media_graph *graph = &entity->pipe->graph;
545 	struct media_pipeline *pipe = entity->pipe;
546 
547 	/*
548 	 * If the following check fails, the driver has performed an
549 	 * unbalanced call to media_pipeline_stop()
550 	 */
551 	if (WARN_ON(!pipe))
552 		return;
553 
554 	if (--pipe->streaming_count)
555 		return;
556 
557 	media_graph_walk_start(graph, entity);
558 
559 	while ((entity = media_graph_walk_next(graph)))
560 		entity->pipe = NULL;
561 
562 	media_graph_walk_cleanup(graph);
563 
564 }
565 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
566 
567 void media_pipeline_stop(struct media_entity *entity)
568 {
569 	struct media_device *mdev = entity->graph_obj.mdev;
570 
571 	mutex_lock(&mdev->graph_mutex);
572 	__media_pipeline_stop(entity);
573 	mutex_unlock(&mdev->graph_mutex);
574 }
575 EXPORT_SYMBOL_GPL(media_pipeline_stop);
576 
577 /* -----------------------------------------------------------------------------
578  * Links management
579  */
580 
581 static struct media_link *media_add_link(struct list_head *head)
582 {
583 	struct media_link *link;
584 
585 	link = kzalloc(sizeof(*link), GFP_KERNEL);
586 	if (link == NULL)
587 		return NULL;
588 
589 	list_add_tail(&link->list, head);
590 
591 	return link;
592 }
593 
594 static void __media_entity_remove_link(struct media_entity *entity,
595 				       struct media_link *link)
596 {
597 	struct media_link *rlink, *tmp;
598 	struct media_entity *remote;
599 
600 	/* Remove the reverse links for a data link. */
601 	if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == MEDIA_LNK_FL_DATA_LINK) {
602 		if (link->source->entity == entity)
603 			remote = link->sink->entity;
604 		else
605 			remote = link->source->entity;
606 
607 		list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
608 			if (rlink != link->reverse)
609 				continue;
610 
611 			if (link->source->entity == entity)
612 				remote->num_backlinks--;
613 
614 			/* Remove the remote link */
615 			list_del(&rlink->list);
616 			media_gobj_destroy(&rlink->graph_obj);
617 			kfree(rlink);
618 
619 			if (--remote->num_links == 0)
620 				break;
621 		}
622 	}
623 
624 	list_del(&link->list);
625 	media_gobj_destroy(&link->graph_obj);
626 	kfree(link);
627 }
628 
629 int media_get_pad_index(struct media_entity *entity, bool is_sink,
630 			enum media_pad_signal_type sig_type)
631 {
632 	int i;
633 	bool pad_is_sink;
634 
635 	if (!entity)
636 		return -EINVAL;
637 
638 	for (i = 0; i < entity->num_pads; i++) {
639 		if (entity->pads[i].flags & MEDIA_PAD_FL_SINK)
640 			pad_is_sink = true;
641 		else if (entity->pads[i].flags & MEDIA_PAD_FL_SOURCE)
642 			pad_is_sink = false;
643 		else
644 			continue;	/* This is an error! */
645 
646 		if (pad_is_sink != is_sink)
647 			continue;
648 		if (entity->pads[i].sig_type == sig_type)
649 			return i;
650 	}
651 	return -EINVAL;
652 }
653 EXPORT_SYMBOL_GPL(media_get_pad_index);
654 
655 int
656 media_create_pad_link(struct media_entity *source, u16 source_pad,
657 			 struct media_entity *sink, u16 sink_pad, u32 flags)
658 {
659 	struct media_link *link;
660 	struct media_link *backlink;
661 
662 	if (WARN_ON(!source || !sink) ||
663 	    WARN_ON(source_pad >= source->num_pads) ||
664 	    WARN_ON(sink_pad >= sink->num_pads))
665 		return -EINVAL;
666 	if (WARN_ON(!(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE)))
667 		return -EINVAL;
668 	if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
669 		return -EINVAL;
670 
671 	link = media_add_link(&source->links);
672 	if (link == NULL)
673 		return -ENOMEM;
674 
675 	link->source = &source->pads[source_pad];
676 	link->sink = &sink->pads[sink_pad];
677 	link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
678 
679 	/* Initialize graph object embedded at the new link */
680 	media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
681 			&link->graph_obj);
682 
683 	/* Create the backlink. Backlinks are used to help graph traversal and
684 	 * are not reported to userspace.
685 	 */
686 	backlink = media_add_link(&sink->links);
687 	if (backlink == NULL) {
688 		__media_entity_remove_link(source, link);
689 		return -ENOMEM;
690 	}
691 
692 	backlink->source = &source->pads[source_pad];
693 	backlink->sink = &sink->pads[sink_pad];
694 	backlink->flags = flags;
695 	backlink->is_backlink = true;
696 
697 	/* Initialize graph object embedded at the new link */
698 	media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
699 			&backlink->graph_obj);
700 
701 	link->reverse = backlink;
702 	backlink->reverse = link;
703 
704 	sink->num_backlinks++;
705 	sink->num_links++;
706 	source->num_links++;
707 
708 	return 0;
709 }
710 EXPORT_SYMBOL_GPL(media_create_pad_link);
711 
712 int media_create_pad_links(const struct media_device *mdev,
713 			   const u32 source_function,
714 			   struct media_entity *source,
715 			   const u16 source_pad,
716 			   const u32 sink_function,
717 			   struct media_entity *sink,
718 			   const u16 sink_pad,
719 			   u32 flags,
720 			   const bool allow_both_undefined)
721 {
722 	struct media_entity *entity;
723 	unsigned function;
724 	int ret;
725 
726 	/* Trivial case: 1:1 relation */
727 	if (source && sink)
728 		return media_create_pad_link(source, source_pad,
729 					     sink, sink_pad, flags);
730 
731 	/* Worse case scenario: n:n relation */
732 	if (!source && !sink) {
733 		if (!allow_both_undefined)
734 			return 0;
735 		media_device_for_each_entity(source, mdev) {
736 			if (source->function != source_function)
737 				continue;
738 			media_device_for_each_entity(sink, mdev) {
739 				if (sink->function != sink_function)
740 					continue;
741 				ret = media_create_pad_link(source, source_pad,
742 							    sink, sink_pad,
743 							    flags);
744 				if (ret)
745 					return ret;
746 				flags &= ~(MEDIA_LNK_FL_ENABLED |
747 					   MEDIA_LNK_FL_IMMUTABLE);
748 			}
749 		}
750 		return 0;
751 	}
752 
753 	/* Handle 1:n and n:1 cases */
754 	if (source)
755 		function = sink_function;
756 	else
757 		function = source_function;
758 
759 	media_device_for_each_entity(entity, mdev) {
760 		if (entity->function != function)
761 			continue;
762 
763 		if (source)
764 			ret = media_create_pad_link(source, source_pad,
765 						    entity, sink_pad, flags);
766 		else
767 			ret = media_create_pad_link(entity, source_pad,
768 						    sink, sink_pad, flags);
769 		if (ret)
770 			return ret;
771 		flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
772 	}
773 	return 0;
774 }
775 EXPORT_SYMBOL_GPL(media_create_pad_links);
776 
777 void __media_entity_remove_links(struct media_entity *entity)
778 {
779 	struct media_link *link, *tmp;
780 
781 	list_for_each_entry_safe(link, tmp, &entity->links, list)
782 		__media_entity_remove_link(entity, link);
783 
784 	entity->num_links = 0;
785 	entity->num_backlinks = 0;
786 }
787 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
788 
789 void media_entity_remove_links(struct media_entity *entity)
790 {
791 	struct media_device *mdev = entity->graph_obj.mdev;
792 
793 	/* Do nothing if the entity is not registered. */
794 	if (mdev == NULL)
795 		return;
796 
797 	mutex_lock(&mdev->graph_mutex);
798 	__media_entity_remove_links(entity);
799 	mutex_unlock(&mdev->graph_mutex);
800 }
801 EXPORT_SYMBOL_GPL(media_entity_remove_links);
802 
803 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
804 {
805 	int ret;
806 
807 	/* Notify both entities. */
808 	ret = media_entity_call(link->source->entity, link_setup,
809 				link->source, link->sink, flags);
810 	if (ret < 0 && ret != -ENOIOCTLCMD)
811 		return ret;
812 
813 	ret = media_entity_call(link->sink->entity, link_setup,
814 				link->sink, link->source, flags);
815 	if (ret < 0 && ret != -ENOIOCTLCMD) {
816 		media_entity_call(link->source->entity, link_setup,
817 				  link->source, link->sink, link->flags);
818 		return ret;
819 	}
820 
821 	link->flags = flags;
822 	link->reverse->flags = link->flags;
823 
824 	return 0;
825 }
826 
827 int __media_entity_setup_link(struct media_link *link, u32 flags)
828 {
829 	const u32 mask = MEDIA_LNK_FL_ENABLED;
830 	struct media_device *mdev;
831 	struct media_entity *source, *sink;
832 	int ret = -EBUSY;
833 
834 	if (link == NULL)
835 		return -EINVAL;
836 
837 	/* The non-modifiable link flags must not be modified. */
838 	if ((link->flags & ~mask) != (flags & ~mask))
839 		return -EINVAL;
840 
841 	if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
842 		return link->flags == flags ? 0 : -EINVAL;
843 
844 	if (link->flags == flags)
845 		return 0;
846 
847 	source = link->source->entity;
848 	sink = link->sink->entity;
849 
850 	if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
851 	    (media_entity_is_streaming(source) ||
852 	     media_entity_is_streaming(sink)))
853 		return -EBUSY;
854 
855 	mdev = source->graph_obj.mdev;
856 
857 	if (mdev->ops && mdev->ops->link_notify) {
858 		ret = mdev->ops->link_notify(link, flags,
859 					     MEDIA_DEV_NOTIFY_PRE_LINK_CH);
860 		if (ret < 0)
861 			return ret;
862 	}
863 
864 	ret = __media_entity_setup_link_notify(link, flags);
865 
866 	if (mdev->ops && mdev->ops->link_notify)
867 		mdev->ops->link_notify(link, flags,
868 				       MEDIA_DEV_NOTIFY_POST_LINK_CH);
869 
870 	return ret;
871 }
872 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
873 
874 int media_entity_setup_link(struct media_link *link, u32 flags)
875 {
876 	int ret;
877 
878 	mutex_lock(&link->graph_obj.mdev->graph_mutex);
879 	ret = __media_entity_setup_link(link, flags);
880 	mutex_unlock(&link->graph_obj.mdev->graph_mutex);
881 
882 	return ret;
883 }
884 EXPORT_SYMBOL_GPL(media_entity_setup_link);
885 
886 struct media_link *
887 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
888 {
889 	struct media_link *link;
890 
891 	list_for_each_entry(link, &source->entity->links, list) {
892 		if (link->source->entity == source->entity &&
893 		    link->source->index == source->index &&
894 		    link->sink->entity == sink->entity &&
895 		    link->sink->index == sink->index)
896 			return link;
897 	}
898 
899 	return NULL;
900 }
901 EXPORT_SYMBOL_GPL(media_entity_find_link);
902 
903 struct media_pad *media_entity_remote_pad(const struct media_pad *pad)
904 {
905 	struct media_link *link;
906 
907 	list_for_each_entry(link, &pad->entity->links, list) {
908 		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
909 			continue;
910 
911 		if (link->source == pad)
912 			return link->sink;
913 
914 		if (link->sink == pad)
915 			return link->source;
916 	}
917 
918 	return NULL;
919 
920 }
921 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
922 
923 static void media_interface_init(struct media_device *mdev,
924 				 struct media_interface *intf,
925 				 u32 gobj_type,
926 				 u32 intf_type, u32 flags)
927 {
928 	intf->type = intf_type;
929 	intf->flags = flags;
930 	INIT_LIST_HEAD(&intf->links);
931 
932 	media_gobj_create(mdev, gobj_type, &intf->graph_obj);
933 }
934 
935 /* Functions related to the media interface via device nodes */
936 
937 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
938 						u32 type, u32 flags,
939 						u32 major, u32 minor)
940 {
941 	struct media_intf_devnode *devnode;
942 
943 	devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
944 	if (!devnode)
945 		return NULL;
946 
947 	devnode->major = major;
948 	devnode->minor = minor;
949 
950 	media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
951 			     type, flags);
952 
953 	return devnode;
954 }
955 EXPORT_SYMBOL_GPL(media_devnode_create);
956 
957 void media_devnode_remove(struct media_intf_devnode *devnode)
958 {
959 	media_remove_intf_links(&devnode->intf);
960 	media_gobj_destroy(&devnode->intf.graph_obj);
961 	kfree(devnode);
962 }
963 EXPORT_SYMBOL_GPL(media_devnode_remove);
964 
965 struct media_link *media_create_intf_link(struct media_entity *entity,
966 					    struct media_interface *intf,
967 					    u32 flags)
968 {
969 	struct media_link *link;
970 
971 	link = media_add_link(&intf->links);
972 	if (link == NULL)
973 		return NULL;
974 
975 	link->intf = intf;
976 	link->entity = entity;
977 	link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
978 
979 	/* Initialize graph object embedded at the new link */
980 	media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
981 			&link->graph_obj);
982 
983 	return link;
984 }
985 EXPORT_SYMBOL_GPL(media_create_intf_link);
986 
987 void __media_remove_intf_link(struct media_link *link)
988 {
989 	list_del(&link->list);
990 	media_gobj_destroy(&link->graph_obj);
991 	kfree(link);
992 }
993 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
994 
995 void media_remove_intf_link(struct media_link *link)
996 {
997 	struct media_device *mdev = link->graph_obj.mdev;
998 
999 	/* Do nothing if the intf is not registered. */
1000 	if (mdev == NULL)
1001 		return;
1002 
1003 	mutex_lock(&mdev->graph_mutex);
1004 	__media_remove_intf_link(link);
1005 	mutex_unlock(&mdev->graph_mutex);
1006 }
1007 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1008 
1009 void __media_remove_intf_links(struct media_interface *intf)
1010 {
1011 	struct media_link *link, *tmp;
1012 
1013 	list_for_each_entry_safe(link, tmp, &intf->links, list)
1014 		__media_remove_intf_link(link);
1015 
1016 }
1017 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1018 
1019 void media_remove_intf_links(struct media_interface *intf)
1020 {
1021 	struct media_device *mdev = intf->graph_obj.mdev;
1022 
1023 	/* Do nothing if the intf is not registered. */
1024 	if (mdev == NULL)
1025 		return;
1026 
1027 	mutex_lock(&mdev->graph_mutex);
1028 	__media_remove_intf_links(intf);
1029 	mutex_unlock(&mdev->graph_mutex);
1030 }
1031 EXPORT_SYMBOL_GPL(media_remove_intf_links);
1032 
1033 struct media_link *media_create_ancillary_link(struct media_entity *primary,
1034 					       struct media_entity *ancillary)
1035 {
1036 	struct media_link *link;
1037 
1038 	link = media_add_link(&primary->links);
1039 	if (!link)
1040 		return ERR_PTR(-ENOMEM);
1041 
1042 	link->gobj0 = &primary->graph_obj;
1043 	link->gobj1 = &ancillary->graph_obj;
1044 	link->flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED |
1045 		      MEDIA_LNK_FL_ANCILLARY_LINK;
1046 
1047 	/* Initialize graph object embedded in the new link */
1048 	media_gobj_create(primary->graph_obj.mdev, MEDIA_GRAPH_LINK,
1049 			  &link->graph_obj);
1050 
1051 	return link;
1052 }
1053 EXPORT_SYMBOL_GPL(media_create_ancillary_link);
1054