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Laurent Pinchart53e269c2009-12-09 08:40:00 -03001/*
2 * Media entity
3 *
4 * Copyright (C) 2010 Nokia Corporation
5 *
6 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
7 * Sakari Ailus <sakari.ailus@iki.fi>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <media/media-entity.h>
Laurent Pinchart503c3d822010-03-07 15:04:59 -030026#include <media/media-device.h>
Laurent Pinchart53e269c2009-12-09 08:40:00 -030027
28/**
29 * media_entity_init - Initialize a media entity
30 *
31 * @num_pads: Total number of sink and source pads.
32 * @extra_links: Initial estimate of the number of extra links.
33 * @pads: Array of 'num_pads' pads.
34 *
35 * The total number of pads is an intrinsic property of entities known by the
36 * entity driver, while the total number of links depends on hardware design
37 * and is an extrinsic property unknown to the entity driver. However, in most
38 * use cases the entity driver can guess the number of links which can safely
39 * be assumed to be equal to or larger than the number of pads.
40 *
41 * For those reasons the links array can be preallocated based on the entity
42 * driver guess and will be reallocated later if extra links need to be
43 * created.
44 *
45 * This function allocates a links array with enough space to hold at least
46 * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
47 * be set to the number of allocated elements.
48 *
49 * The pads array is managed by the entity driver and passed to
50 * media_entity_init() where its pointer will be stored in the entity structure.
51 */
52int
53media_entity_init(struct media_entity *entity, u16 num_pads,
54 struct media_pad *pads, u16 extra_links)
55{
56 struct media_link *links;
57 unsigned int max_links = num_pads + extra_links;
58 unsigned int i;
59
60 links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
61 if (links == NULL)
62 return -ENOMEM;
63
64 entity->group_id = 0;
65 entity->max_links = max_links;
66 entity->num_links = 0;
67 entity->num_backlinks = 0;
68 entity->num_pads = num_pads;
69 entity->pads = pads;
70 entity->links = links;
71
72 for (i = 0; i < num_pads; i++) {
73 pads[i].entity = entity;
74 pads[i].index = i;
75 }
76
77 return 0;
78}
79EXPORT_SYMBOL_GPL(media_entity_init);
80
81void
82media_entity_cleanup(struct media_entity *entity)
83{
84 kfree(entity->links);
85}
86EXPORT_SYMBOL_GPL(media_entity_cleanup);
87
Sakari Ailusa5ccc482010-03-07 16:14:14 -030088/* -----------------------------------------------------------------------------
89 * Graph traversal
90 */
91
92static struct media_entity *
93media_entity_other(struct media_entity *entity, struct media_link *link)
94{
95 if (link->source->entity == entity)
96 return link->sink->entity;
97 else
98 return link->source->entity;
99}
100
101/* push an entity to traversal stack */
102static void stack_push(struct media_entity_graph *graph,
103 struct media_entity *entity)
104{
105 if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
106 WARN_ON(1);
107 return;
108 }
109 graph->top++;
110 graph->stack[graph->top].link = 0;
111 graph->stack[graph->top].entity = entity;
112}
113
114static struct media_entity *stack_pop(struct media_entity_graph *graph)
115{
116 struct media_entity *entity;
117
118 entity = graph->stack[graph->top].entity;
119 graph->top--;
120
121 return entity;
122}
123
124#define stack_peek(en) ((en)->stack[(en)->top - 1].entity)
125#define link_top(en) ((en)->stack[(en)->top].link)
126#define stack_top(en) ((en)->stack[(en)->top].entity)
127
128/**
129 * media_entity_graph_walk_start - Start walking the media graph at a given entity
130 * @graph: Media graph structure that will be used to walk the graph
131 * @entity: Starting entity
132 *
133 * This function initializes the graph traversal structure to walk the entities
134 * graph starting at the given entity. The traversal structure must not be
135 * modified by the caller during graph traversal. When done the structure can
136 * safely be freed.
137 */
138void media_entity_graph_walk_start(struct media_entity_graph *graph,
139 struct media_entity *entity)
140{
141 graph->top = 0;
142 graph->stack[graph->top].entity = NULL;
143 stack_push(graph, entity);
144}
145EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
146
147/**
148 * media_entity_graph_walk_next - Get the next entity in the graph
149 * @graph: Media graph structure
150 *
151 * Perform a depth-first traversal of the given media entities graph.
152 *
153 * The graph structure must have been previously initialized with a call to
154 * media_entity_graph_walk_start().
155 *
156 * Return the next entity in the graph or NULL if the whole graph have been
157 * traversed.
158 */
159struct media_entity *
160media_entity_graph_walk_next(struct media_entity_graph *graph)
161{
162 if (stack_top(graph) == NULL)
163 return NULL;
164
165 /*
166 * Depth first search. Push entity to stack and continue from
167 * top of the stack until no more entities on the level can be
168 * found.
169 */
170 while (link_top(graph) < stack_top(graph)->num_links) {
171 struct media_entity *entity = stack_top(graph);
172 struct media_link *link = &entity->links[link_top(graph)];
173 struct media_entity *next;
174
175 /* The link is not enabled so we do not follow. */
176 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
177 link_top(graph)++;
178 continue;
179 }
180
181 /* Get the entity in the other end of the link . */
182 next = media_entity_other(entity, link);
183
184 /* Was it the entity we came here from? */
185 if (next == stack_peek(graph)) {
186 link_top(graph)++;
187 continue;
188 }
189
190 /* Push the new entity to stack and start over. */
191 link_top(graph)++;
192 stack_push(graph, next);
193 }
194
195 return stack_pop(graph);
196}
197EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
198
199/* -----------------------------------------------------------------------------
Laurent Pincharte02188c2010-08-25 09:00:41 -0300200 * Pipeline management
201 */
202
203/**
204 * media_entity_pipeline_start - Mark a pipeline as streaming
205 * @entity: Starting entity
206 * @pipe: Media pipeline to be assigned to all entities in the pipeline.
207 *
208 * Mark all entities connected to a given entity through enabled links, either
209 * directly or indirectly, as streaming. The given pipeline object is assigned to
210 * every entity in the pipeline and stored in the media_entity pipe field.
211 *
212 * Calls to this function can be nested, in which case the same number of
213 * media_entity_pipeline_stop() calls will be required to stop streaming. The
214 * pipeline pointer must be identical for all nested calls to
215 * media_entity_pipeline_start().
216 */
Sakari Ailusaf88be32012-01-11 06:25:15 -0300217__must_check int media_entity_pipeline_start(struct media_entity *entity,
218 struct media_pipeline *pipe)
Laurent Pincharte02188c2010-08-25 09:00:41 -0300219{
220 struct media_device *mdev = entity->parent;
221 struct media_entity_graph graph;
Sakari Ailusaf88be32012-01-11 06:25:15 -0300222 struct media_entity *entity_err = entity;
223 int ret;
Laurent Pincharte02188c2010-08-25 09:00:41 -0300224
225 mutex_lock(&mdev->graph_mutex);
226
227 media_entity_graph_walk_start(&graph, entity);
228
229 while ((entity = media_entity_graph_walk_next(&graph))) {
Sakari Ailusaf88be32012-01-11 06:25:15 -0300230 unsigned int i;
231
Laurent Pincharte02188c2010-08-25 09:00:41 -0300232 entity->stream_count++;
233 WARN_ON(entity->pipe && entity->pipe != pipe);
234 entity->pipe = pipe;
Sakari Ailusaf88be32012-01-11 06:25:15 -0300235
236 /* Already streaming --- no need to check. */
237 if (entity->stream_count > 1)
238 continue;
239
240 if (!entity->ops || !entity->ops->link_validate)
241 continue;
242
243 for (i = 0; i < entity->num_links; i++) {
244 struct media_link *link = &entity->links[i];
245
246 /* Is this pad part of an enabled link? */
247 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
248 continue;
249
250 /* Are we the sink or not? */
251 if (link->sink->entity != entity)
252 continue;
253
254 ret = entity->ops->link_validate(link);
255 if (ret < 0 && ret != -ENOIOCTLCMD)
256 goto error;
257 }
Laurent Pincharte02188c2010-08-25 09:00:41 -0300258 }
259
260 mutex_unlock(&mdev->graph_mutex);
Sakari Ailusaf88be32012-01-11 06:25:15 -0300261
262 return 0;
263
264error:
265 /*
266 * Link validation on graph failed. We revert what we did and
267 * return the error.
268 */
269 media_entity_graph_walk_start(&graph, entity_err);
270
271 while ((entity_err = media_entity_graph_walk_next(&graph))) {
272 entity_err->stream_count--;
273 if (entity_err->stream_count == 0)
274 entity_err->pipe = NULL;
275
276 /*
277 * We haven't increased stream_count further than this
278 * so we quit here.
279 */
280 if (entity_err == entity)
281 break;
282 }
283
284 mutex_unlock(&mdev->graph_mutex);
285
286 return ret;
Laurent Pincharte02188c2010-08-25 09:00:41 -0300287}
288EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
289
290/**
291 * media_entity_pipeline_stop - Mark a pipeline as not streaming
292 * @entity: Starting entity
293 *
294 * Mark all entities connected to a given entity through enabled links, either
295 * directly or indirectly, as not streaming. The media_entity pipe field is
296 * reset to NULL.
297 *
298 * If multiple calls to media_entity_pipeline_start() have been made, the same
299 * number of calls to this function are required to mark the pipeline as not
300 * streaming.
301 */
302void media_entity_pipeline_stop(struct media_entity *entity)
303{
304 struct media_device *mdev = entity->parent;
305 struct media_entity_graph graph;
306
307 mutex_lock(&mdev->graph_mutex);
308
309 media_entity_graph_walk_start(&graph, entity);
310
311 while ((entity = media_entity_graph_walk_next(&graph))) {
312 entity->stream_count--;
313 if (entity->stream_count == 0)
314 entity->pipe = NULL;
315 }
316
317 mutex_unlock(&mdev->graph_mutex);
318}
319EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
320
321/* -----------------------------------------------------------------------------
Laurent Pinchart503c3d822010-03-07 15:04:59 -0300322 * Module use count
323 */
324
325/*
326 * media_entity_get - Get a reference to the parent module
327 * @entity: The entity
328 *
329 * Get a reference to the parent media device module.
330 *
331 * The function will return immediately if @entity is NULL.
332 *
333 * Return a pointer to the entity on success or NULL on failure.
334 */
335struct media_entity *media_entity_get(struct media_entity *entity)
336{
337 if (entity == NULL)
338 return NULL;
339
340 if (entity->parent->dev &&
341 !try_module_get(entity->parent->dev->driver->owner))
342 return NULL;
343
344 return entity;
345}
346EXPORT_SYMBOL_GPL(media_entity_get);
347
348/*
349 * media_entity_put - Release the reference to the parent module
350 * @entity: The entity
351 *
352 * Release the reference count acquired by media_entity_get().
353 *
354 * The function will return immediately if @entity is NULL.
355 */
356void media_entity_put(struct media_entity *entity)
357{
358 if (entity == NULL)
359 return;
360
361 if (entity->parent->dev)
362 module_put(entity->parent->dev->driver->owner);
363}
364EXPORT_SYMBOL_GPL(media_entity_put);
365
366/* -----------------------------------------------------------------------------
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300367 * Links management
368 */
369
Laurent Pinchart53e269c2009-12-09 08:40:00 -0300370static struct media_link *media_entity_add_link(struct media_entity *entity)
371{
372 if (entity->num_links >= entity->max_links) {
373 struct media_link *links = entity->links;
374 unsigned int max_links = entity->max_links + 2;
375 unsigned int i;
376
377 links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
378 if (links == NULL)
379 return NULL;
380
381 for (i = 0; i < entity->num_links; i++)
382 links[i].reverse->reverse = &links[i];
383
384 entity->max_links = max_links;
385 entity->links = links;
386 }
387
388 return &entity->links[entity->num_links++];
389}
390
391int
392media_entity_create_link(struct media_entity *source, u16 source_pad,
393 struct media_entity *sink, u16 sink_pad, u32 flags)
394{
395 struct media_link *link;
396 struct media_link *backlink;
397
398 BUG_ON(source == NULL || sink == NULL);
399 BUG_ON(source_pad >= source->num_pads);
400 BUG_ON(sink_pad >= sink->num_pads);
401
402 link = media_entity_add_link(source);
403 if (link == NULL)
404 return -ENOMEM;
405
406 link->source = &source->pads[source_pad];
407 link->sink = &sink->pads[sink_pad];
408 link->flags = flags;
409
410 /* Create the backlink. Backlinks are used to help graph traversal and
411 * are not reported to userspace.
412 */
413 backlink = media_entity_add_link(sink);
414 if (backlink == NULL) {
415 source->num_links--;
416 return -ENOMEM;
417 }
418
419 backlink->source = &source->pads[source_pad];
420 backlink->sink = &sink->pads[sink_pad];
421 backlink->flags = flags;
422
423 link->reverse = backlink;
424 backlink->reverse = link;
425
426 sink->num_backlinks++;
427
428 return 0;
429}
430EXPORT_SYMBOL_GPL(media_entity_create_link);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300431
432static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
433{
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300434 int ret;
435
436 /* Notify both entities. */
437 ret = media_entity_call(link->source->entity, link_setup,
438 link->source, link->sink, flags);
439 if (ret < 0 && ret != -ENOIOCTLCMD)
440 return ret;
441
442 ret = media_entity_call(link->sink->entity, link_setup,
443 link->sink, link->source, flags);
444 if (ret < 0 && ret != -ENOIOCTLCMD) {
445 media_entity_call(link->source->entity, link_setup,
446 link->source, link->sink, link->flags);
447 return ret;
448 }
449
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300450 link->flags = flags;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300451 link->reverse->flags = link->flags;
452
453 return 0;
454}
455
456/**
457 * __media_entity_setup_link - Configure a media link
458 * @link: The link being configured
459 * @flags: Link configuration flags
460 *
461 * The bulk of link setup is handled by the two entities connected through the
462 * link. This function notifies both entities of the link configuration change.
463 *
464 * If the link is immutable or if the current and new configuration are
465 * identical, return immediately.
466 *
467 * The user is expected to hold link->source->parent->mutex. If not,
468 * media_entity_setup_link() should be used instead.
469 */
470int __media_entity_setup_link(struct media_link *link, u32 flags)
471{
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300472 const u32 mask = MEDIA_LNK_FL_ENABLED;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300473 struct media_device *mdev;
474 struct media_entity *source, *sink;
475 int ret = -EBUSY;
476
477 if (link == NULL)
478 return -EINVAL;
479
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300480 /* The non-modifiable link flags must not be modified. */
481 if ((link->flags & ~mask) != (flags & ~mask))
482 return -EINVAL;
483
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300484 if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
485 return link->flags == flags ? 0 : -EINVAL;
486
487 if (link->flags == flags)
488 return 0;
489
490 source = link->source->entity;
491 sink = link->sink->entity;
492
Laurent Pincharte02188c2010-08-25 09:00:41 -0300493 if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
494 (source->stream_count || sink->stream_count))
495 return -EBUSY;
496
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300497 mdev = source->parent;
498
499 if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) {
500 ret = mdev->link_notify(link->source, link->sink,
501 MEDIA_LNK_FL_ENABLED);
502 if (ret < 0)
503 return ret;
504 }
505
506 ret = __media_entity_setup_link_notify(link, flags);
507 if (ret < 0)
508 goto err;
509
510 if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
511 mdev->link_notify(link->source, link->sink, 0);
512
513 return 0;
514
515err:
516 if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
517 mdev->link_notify(link->source, link->sink, 0);
518
519 return ret;
520}
521
522int media_entity_setup_link(struct media_link *link, u32 flags)
523{
524 int ret;
525
526 mutex_lock(&link->source->entity->parent->graph_mutex);
527 ret = __media_entity_setup_link(link, flags);
528 mutex_unlock(&link->source->entity->parent->graph_mutex);
529
530 return ret;
531}
532EXPORT_SYMBOL_GPL(media_entity_setup_link);
533
534/**
535 * media_entity_find_link - Find a link between two pads
536 * @source: Source pad
537 * @sink: Sink pad
538 *
539 * Return a pointer to the link between the two entities. If no such link
540 * exists, return NULL.
541 */
542struct media_link *
543media_entity_find_link(struct media_pad *source, struct media_pad *sink)
544{
545 struct media_link *link;
546 unsigned int i;
547
548 for (i = 0; i < source->entity->num_links; ++i) {
549 link = &source->entity->links[i];
550
551 if (link->source->entity == source->entity &&
552 link->source->index == source->index &&
553 link->sink->entity == sink->entity &&
554 link->sink->index == sink->index)
555 return link;
556 }
557
558 return NULL;
559}
560EXPORT_SYMBOL_GPL(media_entity_find_link);
561
562/**
563 * media_entity_remote_source - Find the source pad at the remote end of a link
564 * @pad: Sink pad at the local end of the link
565 *
566 * Search for a remote source pad connected to the given sink pad by iterating
567 * over all links originating or terminating at that pad until an enabled link
568 * is found.
569 *
570 * Return a pointer to the pad at the remote end of the first found enabled
571 * link, or NULL if no enabled link has been found.
572 */
573struct media_pad *media_entity_remote_source(struct media_pad *pad)
574{
575 unsigned int i;
576
577 for (i = 0; i < pad->entity->num_links; i++) {
578 struct media_link *link = &pad->entity->links[i];
579
580 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
581 continue;
582
583 if (link->source == pad)
584 return link->sink;
585
586 if (link->sink == pad)
587 return link->source;
588 }
589
590 return NULL;
591
592}
593EXPORT_SYMBOL_GPL(media_entity_remote_source);