xref: /linux/drivers/media/mc/mc-entity.c (revision 288440de9e5fdb4a3ff73864850f080c1250fc81)
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 
18 static 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 
48 static 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 					  int idx_max)
64 {
65 	idx_max = ALIGN(idx_max, BITS_PER_LONG);
66 	ent_enum->bmap = bitmap_zalloc(idx_max, GFP_KERNEL);
67 	if (!ent_enum->bmap)
68 		return -ENOMEM;
69 
70 	ent_enum->idx_max = idx_max;
71 
72 	return 0;
73 }
74 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
75 
76 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
77 {
78 	bitmap_free(ent_enum->bmap);
79 }
80 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
81 
82 /**
83  *  dev_dbg_obj - Prints in debug mode a change on some object
84  *
85  * @event_name:	Name of the event to report. Could be __func__
86  * @gobj:	Pointer to the object
87  *
88  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
89  * won't produce any code.
90  */
91 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
92 {
93 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
94 	switch (media_type(gobj)) {
95 	case MEDIA_GRAPH_ENTITY:
96 		dev_dbg(gobj->mdev->dev,
97 			"%s id %u: entity '%s'\n",
98 			event_name, media_id(gobj),
99 			gobj_to_entity(gobj)->name);
100 		break;
101 	case MEDIA_GRAPH_LINK:
102 	{
103 		struct media_link *link = gobj_to_link(gobj);
104 
105 		dev_dbg(gobj->mdev->dev,
106 			"%s id %u: %s link id %u ==> id %u\n",
107 			event_name, media_id(gobj), link_type_name(link),
108 			media_id(link->gobj0),
109 			media_id(link->gobj1));
110 		break;
111 	}
112 	case MEDIA_GRAPH_PAD:
113 	{
114 		struct media_pad *pad = gobj_to_pad(gobj);
115 
116 		dev_dbg(gobj->mdev->dev,
117 			"%s id %u: %s%spad '%s':%d\n",
118 			event_name, media_id(gobj),
119 			pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
120 			pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
121 			pad->entity->name, pad->index);
122 		break;
123 	}
124 	case MEDIA_GRAPH_INTF_DEVNODE:
125 	{
126 		struct media_interface *intf = gobj_to_intf(gobj);
127 		struct media_intf_devnode *devnode = intf_to_devnode(intf);
128 
129 		dev_dbg(gobj->mdev->dev,
130 			"%s id %u: intf_devnode %s - major: %d, minor: %d\n",
131 			event_name, media_id(gobj),
132 			intf_type(intf),
133 			devnode->major, devnode->minor);
134 		break;
135 	}
136 	}
137 #endif
138 }
139 
140 void media_gobj_create(struct media_device *mdev,
141 			   enum media_gobj_type type,
142 			   struct media_gobj *gobj)
143 {
144 	BUG_ON(!mdev);
145 
146 	gobj->mdev = mdev;
147 
148 	/* Create a per-type unique object ID */
149 	gobj->id = media_gobj_gen_id(type, ++mdev->id);
150 
151 	switch (type) {
152 	case MEDIA_GRAPH_ENTITY:
153 		list_add_tail(&gobj->list, &mdev->entities);
154 		break;
155 	case MEDIA_GRAPH_PAD:
156 		list_add_tail(&gobj->list, &mdev->pads);
157 		break;
158 	case MEDIA_GRAPH_LINK:
159 		list_add_tail(&gobj->list, &mdev->links);
160 		break;
161 	case MEDIA_GRAPH_INTF_DEVNODE:
162 		list_add_tail(&gobj->list, &mdev->interfaces);
163 		break;
164 	}
165 
166 	mdev->topology_version++;
167 
168 	dev_dbg_obj(__func__, gobj);
169 }
170 
171 void media_gobj_destroy(struct media_gobj *gobj)
172 {
173 	/* Do nothing if the object is not linked. */
174 	if (gobj->mdev == NULL)
175 		return;
176 
177 	dev_dbg_obj(__func__, gobj);
178 
179 	gobj->mdev->topology_version++;
180 
181 	/* Remove the object from mdev list */
182 	list_del(&gobj->list);
183 
184 	gobj->mdev = NULL;
185 }
186 
187 /*
188  * TODO: Get rid of this.
189  */
190 #define MEDIA_ENTITY_MAX_PADS		512
191 
192 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
193 			   struct media_pad *pads)
194 {
195 	struct media_device *mdev = entity->graph_obj.mdev;
196 	unsigned int i;
197 
198 	if (num_pads >= MEDIA_ENTITY_MAX_PADS)
199 		return -E2BIG;
200 
201 	entity->num_pads = num_pads;
202 	entity->pads = pads;
203 
204 	if (mdev)
205 		mutex_lock(&mdev->graph_mutex);
206 
207 	for (i = 0; i < num_pads; i++) {
208 		pads[i].entity = entity;
209 		pads[i].index = i;
210 		if (mdev)
211 			media_gobj_create(mdev, MEDIA_GRAPH_PAD,
212 					&entity->pads[i].graph_obj);
213 	}
214 
215 	if (mdev)
216 		mutex_unlock(&mdev->graph_mutex);
217 
218 	return 0;
219 }
220 EXPORT_SYMBOL_GPL(media_entity_pads_init);
221 
222 /* -----------------------------------------------------------------------------
223  * Graph traversal
224  */
225 
226 static struct media_entity *
227 media_entity_other(struct media_entity *entity, struct media_link *link)
228 {
229 	if (link->source->entity == entity)
230 		return link->sink->entity;
231 	else
232 		return link->source->entity;
233 }
234 
235 /* push an entity to traversal stack */
236 static void stack_push(struct media_graph *graph,
237 		       struct media_entity *entity)
238 {
239 	if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
240 		WARN_ON(1);
241 		return;
242 	}
243 	graph->top++;
244 	graph->stack[graph->top].link = entity->links.next;
245 	graph->stack[graph->top].entity = entity;
246 }
247 
248 static struct media_entity *stack_pop(struct media_graph *graph)
249 {
250 	struct media_entity *entity;
251 
252 	entity = graph->stack[graph->top].entity;
253 	graph->top--;
254 
255 	return entity;
256 }
257 
258 #define link_top(en)	((en)->stack[(en)->top].link)
259 #define stack_top(en)	((en)->stack[(en)->top].entity)
260 
261 /**
262  * media_graph_walk_init - Allocate resources for graph walk
263  * @graph: Media graph structure that will be used to walk the graph
264  * @mdev: Media device
265  *
266  * Reserve resources for graph walk in media device's current
267  * state. The memory must be released using
268  * media_graph_walk_free().
269  *
270  * Returns error on failure, zero on success.
271  */
272 __must_check int media_graph_walk_init(
273 	struct media_graph *graph, struct media_device *mdev)
274 {
275 	return media_entity_enum_init(&graph->ent_enum, mdev);
276 }
277 EXPORT_SYMBOL_GPL(media_graph_walk_init);
278 
279 /**
280  * media_graph_walk_cleanup - Release resources related to graph walking
281  * @graph: Media graph structure that was used to walk the graph
282  */
283 void media_graph_walk_cleanup(struct media_graph *graph)
284 {
285 	media_entity_enum_cleanup(&graph->ent_enum);
286 }
287 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
288 
289 void media_graph_walk_start(struct media_graph *graph,
290 			    struct media_entity *entity)
291 {
292 	media_entity_enum_zero(&graph->ent_enum);
293 	media_entity_enum_set(&graph->ent_enum, entity);
294 
295 	graph->top = 0;
296 	graph->stack[graph->top].entity = NULL;
297 	stack_push(graph, entity);
298 	dev_dbg(entity->graph_obj.mdev->dev,
299 		"begin graph walk at '%s'\n", entity->name);
300 }
301 EXPORT_SYMBOL_GPL(media_graph_walk_start);
302 
303 static void media_graph_walk_iter(struct media_graph *graph)
304 {
305 	struct media_entity *entity = stack_top(graph);
306 	struct media_link *link;
307 	struct media_entity *next;
308 
309 	link = list_entry(link_top(graph), typeof(*link), list);
310 
311 	/* If the link is not a data link, don't follow it */
312 	if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) != MEDIA_LNK_FL_DATA_LINK) {
313 		link_top(graph) = link_top(graph)->next;
314 		return;
315 	}
316 
317 	/* The link is not enabled so we do not follow. */
318 	if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
319 		link_top(graph) = link_top(graph)->next;
320 		dev_dbg(entity->graph_obj.mdev->dev,
321 			"walk: skipping disabled link '%s':%u -> '%s':%u\n",
322 			link->source->entity->name, link->source->index,
323 			link->sink->entity->name, link->sink->index);
324 		return;
325 	}
326 
327 	/* Get the entity at the other end of the link. */
328 	next = media_entity_other(entity, link);
329 
330 	/* Has the entity already been visited? */
331 	if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
332 		link_top(graph) = link_top(graph)->next;
333 		dev_dbg(entity->graph_obj.mdev->dev,
334 			"walk: skipping entity '%s' (already seen)\n",
335 			next->name);
336 		return;
337 	}
338 
339 	/* Push the new entity to stack and start over. */
340 	link_top(graph) = link_top(graph)->next;
341 	stack_push(graph, next);
342 	dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
343 		next->name);
344 	lockdep_assert_held(&entity->graph_obj.mdev->graph_mutex);
345 }
346 
347 struct media_entity *media_graph_walk_next(struct media_graph *graph)
348 {
349 	struct media_entity *entity;
350 
351 	if (stack_top(graph) == NULL)
352 		return NULL;
353 
354 	/*
355 	 * Depth first search. Push entity to stack and continue from
356 	 * top of the stack until no more entities on the level can be
357 	 * found.
358 	 */
359 	while (link_top(graph) != &stack_top(graph)->links)
360 		media_graph_walk_iter(graph);
361 
362 	entity = stack_pop(graph);
363 	dev_dbg(entity->graph_obj.mdev->dev,
364 		"walk: returning entity '%s'\n", entity->name);
365 
366 	return entity;
367 }
368 EXPORT_SYMBOL_GPL(media_graph_walk_next);
369 
370 int media_entity_get_fwnode_pad(struct media_entity *entity,
371 				struct fwnode_handle *fwnode,
372 				unsigned long direction_flags)
373 {
374 	struct fwnode_endpoint endpoint;
375 	unsigned int i;
376 	int ret;
377 
378 	if (!entity->ops || !entity->ops->get_fwnode_pad) {
379 		for (i = 0; i < entity->num_pads; i++) {
380 			if (entity->pads[i].flags & direction_flags)
381 				return i;
382 		}
383 
384 		return -ENXIO;
385 	}
386 
387 	ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
388 	if (ret)
389 		return ret;
390 
391 	ret = entity->ops->get_fwnode_pad(entity, &endpoint);
392 	if (ret < 0)
393 		return ret;
394 
395 	if (ret >= entity->num_pads)
396 		return -ENXIO;
397 
398 	if (!(entity->pads[ret].flags & direction_flags))
399 		return -ENXIO;
400 
401 	return ret;
402 }
403 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
404 
405 /* -----------------------------------------------------------------------------
406  * Pipeline management
407  */
408 
409 __must_check int __media_pipeline_start(struct media_entity *entity,
410 					struct media_pipeline *pipe)
411 {
412 	struct media_device *mdev = entity->graph_obj.mdev;
413 	struct media_graph *graph = &pipe->graph;
414 	struct media_entity *entity_err = entity;
415 	struct media_link *link;
416 	int ret;
417 
418 	if (pipe->streaming_count) {
419 		pipe->streaming_count++;
420 		return 0;
421 	}
422 
423 	ret = media_graph_walk_init(&pipe->graph, mdev);
424 	if (ret)
425 		return ret;
426 
427 	media_graph_walk_start(&pipe->graph, entity);
428 
429 	while ((entity = media_graph_walk_next(graph))) {
430 		DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
431 		DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
432 
433 		if (entity->pipe && entity->pipe != pipe) {
434 			pr_err("Pipe active for %s. Can't start for %s\n",
435 				entity->name,
436 				entity_err->name);
437 			ret = -EBUSY;
438 			goto error;
439 		}
440 
441 		/* Already streaming --- no need to check. */
442 		if (entity->pipe)
443 			continue;
444 
445 		entity->pipe = pipe;
446 
447 		if (!entity->ops || !entity->ops->link_validate)
448 			continue;
449 
450 		bitmap_zero(active, entity->num_pads);
451 		bitmap_fill(has_no_links, entity->num_pads);
452 
453 		for_each_media_entity_data_link(entity, link) {
454 			struct media_pad *pad = link->sink->entity == entity
455 						? link->sink : link->source;
456 
457 			/* Mark that a pad is connected by a link. */
458 			bitmap_clear(has_no_links, pad->index, 1);
459 
460 			/*
461 			 * Pads that either do not need to connect or
462 			 * are connected through an enabled link are
463 			 * fine.
464 			 */
465 			if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
466 			    link->flags & MEDIA_LNK_FL_ENABLED)
467 				bitmap_set(active, pad->index, 1);
468 
469 			/*
470 			 * Link validation will only take place for
471 			 * sink ends of the link that are enabled.
472 			 */
473 			if (link->sink != pad ||
474 			    !(link->flags & MEDIA_LNK_FL_ENABLED))
475 				continue;
476 
477 			ret = entity->ops->link_validate(link);
478 			if (ret < 0 && ret != -ENOIOCTLCMD) {
479 				dev_dbg(entity->graph_obj.mdev->dev,
480 					"link validation failed for '%s':%u -> '%s':%u, error %d\n",
481 					link->source->entity->name,
482 					link->source->index,
483 					entity->name, link->sink->index, ret);
484 				goto error;
485 			}
486 		}
487 
488 		/* Either no links or validated links are fine. */
489 		bitmap_or(active, active, has_no_links, entity->num_pads);
490 
491 		if (!bitmap_full(active, entity->num_pads)) {
492 			ret = -ENOLINK;
493 			dev_dbg(entity->graph_obj.mdev->dev,
494 				"'%s':%u must be connected by an enabled link\n",
495 				entity->name,
496 				(unsigned)find_first_zero_bit(
497 					active, entity->num_pads));
498 			goto error;
499 		}
500 	}
501 
502 	pipe->streaming_count++;
503 
504 	return 0;
505 
506 error:
507 	/*
508 	 * Link validation on graph failed. We revert what we did and
509 	 * return the error.
510 	 */
511 	media_graph_walk_start(graph, entity_err);
512 
513 	while ((entity_err = media_graph_walk_next(graph))) {
514 		entity_err->pipe = NULL;
515 
516 		/*
517 		 * We haven't started entities further than this so we quit
518 		 * here.
519 		 */
520 		if (entity_err == entity)
521 			break;
522 	}
523 
524 	media_graph_walk_cleanup(graph);
525 
526 	return ret;
527 }
528 EXPORT_SYMBOL_GPL(__media_pipeline_start);
529 
530 __must_check int media_pipeline_start(struct media_entity *entity,
531 				      struct media_pipeline *pipe)
532 {
533 	struct media_device *mdev = entity->graph_obj.mdev;
534 	int ret;
535 
536 	mutex_lock(&mdev->graph_mutex);
537 	ret = __media_pipeline_start(entity, pipe);
538 	mutex_unlock(&mdev->graph_mutex);
539 	return ret;
540 }
541 EXPORT_SYMBOL_GPL(media_pipeline_start);
542 
543 void __media_pipeline_stop(struct media_entity *entity)
544 {
545 	struct media_graph *graph = &entity->pipe->graph;
546 	struct media_pipeline *pipe = entity->pipe;
547 
548 	/*
549 	 * If the following check fails, the driver has performed an
550 	 * unbalanced call to media_pipeline_stop()
551 	 */
552 	if (WARN_ON(!pipe))
553 		return;
554 
555 	if (--pipe->streaming_count)
556 		return;
557 
558 	media_graph_walk_start(graph, entity);
559 
560 	while ((entity = media_graph_walk_next(graph)))
561 		entity->pipe = NULL;
562 
563 	media_graph_walk_cleanup(graph);
564 
565 }
566 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
567 
568 void media_pipeline_stop(struct media_entity *entity)
569 {
570 	struct media_device *mdev = entity->graph_obj.mdev;
571 
572 	mutex_lock(&mdev->graph_mutex);
573 	__media_pipeline_stop(entity);
574 	mutex_unlock(&mdev->graph_mutex);
575 }
576 EXPORT_SYMBOL_GPL(media_pipeline_stop);
577 
578 /* -----------------------------------------------------------------------------
579  * Links management
580  */
581 
582 static struct media_link *media_add_link(struct list_head *head)
583 {
584 	struct media_link *link;
585 
586 	link = kzalloc(sizeof(*link), GFP_KERNEL);
587 	if (link == NULL)
588 		return NULL;
589 
590 	list_add_tail(&link->list, head);
591 
592 	return link;
593 }
594 
595 static void __media_entity_remove_link(struct media_entity *entity,
596 				       struct media_link *link)
597 {
598 	struct media_link *rlink, *tmp;
599 	struct media_entity *remote;
600 
601 	/* Remove the reverse links for a data link. */
602 	if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == MEDIA_LNK_FL_DATA_LINK) {
603 		if (link->source->entity == entity)
604 			remote = link->sink->entity;
605 		else
606 			remote = link->source->entity;
607 
608 		list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
609 			if (rlink != link->reverse)
610 				continue;
611 
612 			if (link->source->entity == entity)
613 				remote->num_backlinks--;
614 
615 			/* Remove the remote link */
616 			list_del(&rlink->list);
617 			media_gobj_destroy(&rlink->graph_obj);
618 			kfree(rlink);
619 
620 			if (--remote->num_links == 0)
621 				break;
622 		}
623 	}
624 
625 	list_del(&link->list);
626 	media_gobj_destroy(&link->graph_obj);
627 	kfree(link);
628 }
629 
630 int media_get_pad_index(struct media_entity *entity, bool is_sink,
631 			enum media_pad_signal_type sig_type)
632 {
633 	int i;
634 	bool pad_is_sink;
635 
636 	if (!entity)
637 		return -EINVAL;
638 
639 	for (i = 0; i < entity->num_pads; i++) {
640 		if (entity->pads[i].flags & MEDIA_PAD_FL_SINK)
641 			pad_is_sink = true;
642 		else if (entity->pads[i].flags & MEDIA_PAD_FL_SOURCE)
643 			pad_is_sink = false;
644 		else
645 			continue;	/* This is an error! */
646 
647 		if (pad_is_sink != is_sink)
648 			continue;
649 		if (entity->pads[i].sig_type == sig_type)
650 			return i;
651 	}
652 	return -EINVAL;
653 }
654 EXPORT_SYMBOL_GPL(media_get_pad_index);
655 
656 int
657 media_create_pad_link(struct media_entity *source, u16 source_pad,
658 			 struct media_entity *sink, u16 sink_pad, u32 flags)
659 {
660 	struct media_link *link;
661 	struct media_link *backlink;
662 
663 	if (WARN_ON(!source || !sink) ||
664 	    WARN_ON(source_pad >= source->num_pads) ||
665 	    WARN_ON(sink_pad >= sink->num_pads))
666 		return -EINVAL;
667 	if (WARN_ON(!(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE)))
668 		return -EINVAL;
669 	if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
670 		return -EINVAL;
671 
672 	link = media_add_link(&source->links);
673 	if (link == NULL)
674 		return -ENOMEM;
675 
676 	link->source = &source->pads[source_pad];
677 	link->sink = &sink->pads[sink_pad];
678 	link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
679 
680 	/* Initialize graph object embedded at the new link */
681 	media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
682 			&link->graph_obj);
683 
684 	/* Create the backlink. Backlinks are used to help graph traversal and
685 	 * are not reported to userspace.
686 	 */
687 	backlink = media_add_link(&sink->links);
688 	if (backlink == NULL) {
689 		__media_entity_remove_link(source, link);
690 		return -ENOMEM;
691 	}
692 
693 	backlink->source = &source->pads[source_pad];
694 	backlink->sink = &sink->pads[sink_pad];
695 	backlink->flags = flags;
696 	backlink->is_backlink = true;
697 
698 	/* Initialize graph object embedded at the new link */
699 	media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
700 			&backlink->graph_obj);
701 
702 	link->reverse = backlink;
703 	backlink->reverse = link;
704 
705 	sink->num_backlinks++;
706 	sink->num_links++;
707 	source->num_links++;
708 
709 	return 0;
710 }
711 EXPORT_SYMBOL_GPL(media_create_pad_link);
712 
713 int media_create_pad_links(const struct media_device *mdev,
714 			   const u32 source_function,
715 			   struct media_entity *source,
716 			   const u16 source_pad,
717 			   const u32 sink_function,
718 			   struct media_entity *sink,
719 			   const u16 sink_pad,
720 			   u32 flags,
721 			   const bool allow_both_undefined)
722 {
723 	struct media_entity *entity;
724 	unsigned function;
725 	int ret;
726 
727 	/* Trivial case: 1:1 relation */
728 	if (source && sink)
729 		return media_create_pad_link(source, source_pad,
730 					     sink, sink_pad, flags);
731 
732 	/* Worse case scenario: n:n relation */
733 	if (!source && !sink) {
734 		if (!allow_both_undefined)
735 			return 0;
736 		media_device_for_each_entity(source, mdev) {
737 			if (source->function != source_function)
738 				continue;
739 			media_device_for_each_entity(sink, mdev) {
740 				if (sink->function != sink_function)
741 					continue;
742 				ret = media_create_pad_link(source, source_pad,
743 							    sink, sink_pad,
744 							    flags);
745 				if (ret)
746 					return ret;
747 				flags &= ~(MEDIA_LNK_FL_ENABLED |
748 					   MEDIA_LNK_FL_IMMUTABLE);
749 			}
750 		}
751 		return 0;
752 	}
753 
754 	/* Handle 1:n and n:1 cases */
755 	if (source)
756 		function = sink_function;
757 	else
758 		function = source_function;
759 
760 	media_device_for_each_entity(entity, mdev) {
761 		if (entity->function != function)
762 			continue;
763 
764 		if (source)
765 			ret = media_create_pad_link(source, source_pad,
766 						    entity, sink_pad, flags);
767 		else
768 			ret = media_create_pad_link(entity, source_pad,
769 						    sink, sink_pad, flags);
770 		if (ret)
771 			return ret;
772 		flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
773 	}
774 	return 0;
775 }
776 EXPORT_SYMBOL_GPL(media_create_pad_links);
777 
778 void __media_entity_remove_links(struct media_entity *entity)
779 {
780 	struct media_link *link, *tmp;
781 
782 	list_for_each_entry_safe(link, tmp, &entity->links, list)
783 		__media_entity_remove_link(entity, link);
784 
785 	entity->num_links = 0;
786 	entity->num_backlinks = 0;
787 }
788 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
789 
790 void media_entity_remove_links(struct media_entity *entity)
791 {
792 	struct media_device *mdev = entity->graph_obj.mdev;
793 
794 	/* Do nothing if the entity is not registered. */
795 	if (mdev == NULL)
796 		return;
797 
798 	mutex_lock(&mdev->graph_mutex);
799 	__media_entity_remove_links(entity);
800 	mutex_unlock(&mdev->graph_mutex);
801 }
802 EXPORT_SYMBOL_GPL(media_entity_remove_links);
803 
804 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
805 {
806 	int ret;
807 
808 	/* Notify both entities. */
809 	ret = media_entity_call(link->source->entity, link_setup,
810 				link->source, link->sink, flags);
811 	if (ret < 0 && ret != -ENOIOCTLCMD)
812 		return ret;
813 
814 	ret = media_entity_call(link->sink->entity, link_setup,
815 				link->sink, link->source, flags);
816 	if (ret < 0 && ret != -ENOIOCTLCMD) {
817 		media_entity_call(link->source->entity, link_setup,
818 				  link->source, link->sink, link->flags);
819 		return ret;
820 	}
821 
822 	link->flags = flags;
823 	link->reverse->flags = link->flags;
824 
825 	return 0;
826 }
827 
828 int __media_entity_setup_link(struct media_link *link, u32 flags)
829 {
830 	const u32 mask = MEDIA_LNK_FL_ENABLED;
831 	struct media_device *mdev;
832 	struct media_entity *source, *sink;
833 	int ret = -EBUSY;
834 
835 	if (link == NULL)
836 		return -EINVAL;
837 
838 	/* The non-modifiable link flags must not be modified. */
839 	if ((link->flags & ~mask) != (flags & ~mask))
840 		return -EINVAL;
841 
842 	if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
843 		return link->flags == flags ? 0 : -EINVAL;
844 
845 	if (link->flags == flags)
846 		return 0;
847 
848 	source = link->source->entity;
849 	sink = link->sink->entity;
850 
851 	if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
852 	    (media_entity_is_streaming(source) ||
853 	     media_entity_is_streaming(sink)))
854 		return -EBUSY;
855 
856 	mdev = source->graph_obj.mdev;
857 
858 	if (mdev->ops && mdev->ops->link_notify) {
859 		ret = mdev->ops->link_notify(link, flags,
860 					     MEDIA_DEV_NOTIFY_PRE_LINK_CH);
861 		if (ret < 0)
862 			return ret;
863 	}
864 
865 	ret = __media_entity_setup_link_notify(link, flags);
866 
867 	if (mdev->ops && mdev->ops->link_notify)
868 		mdev->ops->link_notify(link, flags,
869 				       MEDIA_DEV_NOTIFY_POST_LINK_CH);
870 
871 	return ret;
872 }
873 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
874 
875 int media_entity_setup_link(struct media_link *link, u32 flags)
876 {
877 	int ret;
878 
879 	mutex_lock(&link->graph_obj.mdev->graph_mutex);
880 	ret = __media_entity_setup_link(link, flags);
881 	mutex_unlock(&link->graph_obj.mdev->graph_mutex);
882 
883 	return ret;
884 }
885 EXPORT_SYMBOL_GPL(media_entity_setup_link);
886 
887 struct media_link *
888 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
889 {
890 	struct media_link *link;
891 
892 	for_each_media_entity_data_link(source->entity, link) {
893 		if (link->source->entity == source->entity &&
894 		    link->source->index == source->index &&
895 		    link->sink->entity == sink->entity &&
896 		    link->sink->index == sink->index)
897 			return link;
898 	}
899 
900 	return NULL;
901 }
902 EXPORT_SYMBOL_GPL(media_entity_find_link);
903 
904 struct media_pad *media_pad_remote_pad_first(const struct media_pad *pad)
905 {
906 	struct media_link *link;
907 
908 	for_each_media_entity_data_link(pad->entity, link) {
909 		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
910 			continue;
911 
912 		if (link->source == pad)
913 			return link->sink;
914 
915 		if (link->sink == pad)
916 			return link->source;
917 	}
918 
919 	return NULL;
920 
921 }
922 EXPORT_SYMBOL_GPL(media_pad_remote_pad_first);
923 
924 struct media_pad *
925 media_entity_remote_pad_unique(const struct media_entity *entity,
926 			       unsigned int type)
927 {
928 	struct media_pad *pad = NULL;
929 	struct media_link *link;
930 
931 	list_for_each_entry(link, &entity->links, list) {
932 		struct media_pad *local_pad;
933 		struct media_pad *remote_pad;
934 
935 		if (((link->flags & MEDIA_LNK_FL_LINK_TYPE) !=
936 		     MEDIA_LNK_FL_DATA_LINK) ||
937 		    !(link->flags & MEDIA_LNK_FL_ENABLED))
938 			continue;
939 
940 		if (type == MEDIA_PAD_FL_SOURCE) {
941 			local_pad = link->sink;
942 			remote_pad = link->source;
943 		} else {
944 			local_pad = link->source;
945 			remote_pad = link->sink;
946 		}
947 
948 		if (local_pad->entity == entity) {
949 			if (pad)
950 				return ERR_PTR(-ENOTUNIQ);
951 
952 			pad = remote_pad;
953 		}
954 	}
955 
956 	if (!pad)
957 		return ERR_PTR(-ENOLINK);
958 
959 	return pad;
960 }
961 EXPORT_SYMBOL_GPL(media_entity_remote_pad_unique);
962 
963 struct media_pad *media_pad_remote_pad_unique(const struct media_pad *pad)
964 {
965 	struct media_pad *found_pad = NULL;
966 	struct media_link *link;
967 
968 	list_for_each_entry(link, &pad->entity->links, list) {
969 		struct media_pad *remote_pad;
970 
971 		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
972 			continue;
973 
974 		if (link->sink == pad)
975 			remote_pad = link->source;
976 		else if (link->source == pad)
977 			remote_pad = link->sink;
978 		else
979 			continue;
980 
981 		if (found_pad)
982 			return ERR_PTR(-ENOTUNIQ);
983 
984 		found_pad = remote_pad;
985 	}
986 
987 	if (!found_pad)
988 		return ERR_PTR(-ENOLINK);
989 
990 	return found_pad;
991 }
992 EXPORT_SYMBOL_GPL(media_pad_remote_pad_unique);
993 
994 static void media_interface_init(struct media_device *mdev,
995 				 struct media_interface *intf,
996 				 u32 gobj_type,
997 				 u32 intf_type, u32 flags)
998 {
999 	intf->type = intf_type;
1000 	intf->flags = flags;
1001 	INIT_LIST_HEAD(&intf->links);
1002 
1003 	media_gobj_create(mdev, gobj_type, &intf->graph_obj);
1004 }
1005 
1006 /* Functions related to the media interface via device nodes */
1007 
1008 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
1009 						u32 type, u32 flags,
1010 						u32 major, u32 minor)
1011 {
1012 	struct media_intf_devnode *devnode;
1013 
1014 	devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
1015 	if (!devnode)
1016 		return NULL;
1017 
1018 	devnode->major = major;
1019 	devnode->minor = minor;
1020 
1021 	media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
1022 			     type, flags);
1023 
1024 	return devnode;
1025 }
1026 EXPORT_SYMBOL_GPL(media_devnode_create);
1027 
1028 void media_devnode_remove(struct media_intf_devnode *devnode)
1029 {
1030 	media_remove_intf_links(&devnode->intf);
1031 	media_gobj_destroy(&devnode->intf.graph_obj);
1032 	kfree(devnode);
1033 }
1034 EXPORT_SYMBOL_GPL(media_devnode_remove);
1035 
1036 struct media_link *media_create_intf_link(struct media_entity *entity,
1037 					    struct media_interface *intf,
1038 					    u32 flags)
1039 {
1040 	struct media_link *link;
1041 
1042 	link = media_add_link(&intf->links);
1043 	if (link == NULL)
1044 		return NULL;
1045 
1046 	link->intf = intf;
1047 	link->entity = entity;
1048 	link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
1049 
1050 	/* Initialize graph object embedded at the new link */
1051 	media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
1052 			&link->graph_obj);
1053 
1054 	return link;
1055 }
1056 EXPORT_SYMBOL_GPL(media_create_intf_link);
1057 
1058 void __media_remove_intf_link(struct media_link *link)
1059 {
1060 	list_del(&link->list);
1061 	media_gobj_destroy(&link->graph_obj);
1062 	kfree(link);
1063 }
1064 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
1065 
1066 void media_remove_intf_link(struct media_link *link)
1067 {
1068 	struct media_device *mdev = link->graph_obj.mdev;
1069 
1070 	/* Do nothing if the intf is not registered. */
1071 	if (mdev == NULL)
1072 		return;
1073 
1074 	mutex_lock(&mdev->graph_mutex);
1075 	__media_remove_intf_link(link);
1076 	mutex_unlock(&mdev->graph_mutex);
1077 }
1078 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1079 
1080 void __media_remove_intf_links(struct media_interface *intf)
1081 {
1082 	struct media_link *link, *tmp;
1083 
1084 	list_for_each_entry_safe(link, tmp, &intf->links, list)
1085 		__media_remove_intf_link(link);
1086 
1087 }
1088 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1089 
1090 void media_remove_intf_links(struct media_interface *intf)
1091 {
1092 	struct media_device *mdev = intf->graph_obj.mdev;
1093 
1094 	/* Do nothing if the intf is not registered. */
1095 	if (mdev == NULL)
1096 		return;
1097 
1098 	mutex_lock(&mdev->graph_mutex);
1099 	__media_remove_intf_links(intf);
1100 	mutex_unlock(&mdev->graph_mutex);
1101 }
1102 EXPORT_SYMBOL_GPL(media_remove_intf_links);
1103 
1104 struct media_link *media_create_ancillary_link(struct media_entity *primary,
1105 					       struct media_entity *ancillary)
1106 {
1107 	struct media_link *link;
1108 
1109 	link = media_add_link(&primary->links);
1110 	if (!link)
1111 		return ERR_PTR(-ENOMEM);
1112 
1113 	link->gobj0 = &primary->graph_obj;
1114 	link->gobj1 = &ancillary->graph_obj;
1115 	link->flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED |
1116 		      MEDIA_LNK_FL_ANCILLARY_LINK;
1117 
1118 	/* Initialize graph object embedded in the new link */
1119 	media_gobj_create(primary->graph_obj.mdev, MEDIA_GRAPH_LINK,
1120 			  &link->graph_obj);
1121 
1122 	return link;
1123 }
1124 EXPORT_SYMBOL_GPL(media_create_ancillary_link);
1125 
1126 struct media_link *__media_entity_next_link(struct media_entity *entity,
1127 					    struct media_link *link,
1128 					    unsigned long link_type)
1129 {
1130 	link = link ? list_next_entry(link, list)
1131 		    : list_first_entry(&entity->links, typeof(*link), list);
1132 
1133 	list_for_each_entry_from(link, &entity->links, list)
1134 		if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == link_type)
1135 			return link;
1136 
1137 	return NULL;
1138 }
1139 EXPORT_SYMBOL_GPL(__media_entity_next_link);
1140