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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 Pinchart503c3d82010-03-07 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 */
217void media_entity_pipeline_start(struct media_entity *entity,
218 struct media_pipeline *pipe)
219{
220 struct media_device *mdev = entity->parent;
221 struct media_entity_graph graph;
222
223 mutex_lock(&mdev->graph_mutex);
224
225 media_entity_graph_walk_start(&graph, entity);
226
227 while ((entity = media_entity_graph_walk_next(&graph))) {
228 entity->stream_count++;
229 WARN_ON(entity->pipe && entity->pipe != pipe);
230 entity->pipe = pipe;
231 }
232
233 mutex_unlock(&mdev->graph_mutex);
234}
235EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
236
237/**
238 * media_entity_pipeline_stop - Mark a pipeline as not streaming
239 * @entity: Starting entity
240 *
241 * Mark all entities connected to a given entity through enabled links, either
242 * directly or indirectly, as not streaming. The media_entity pipe field is
243 * reset to NULL.
244 *
245 * If multiple calls to media_entity_pipeline_start() have been made, the same
246 * number of calls to this function are required to mark the pipeline as not
247 * streaming.
248 */
249void media_entity_pipeline_stop(struct media_entity *entity)
250{
251 struct media_device *mdev = entity->parent;
252 struct media_entity_graph graph;
253
254 mutex_lock(&mdev->graph_mutex);
255
256 media_entity_graph_walk_start(&graph, entity);
257
258 while ((entity = media_entity_graph_walk_next(&graph))) {
259 entity->stream_count--;
260 if (entity->stream_count == 0)
261 entity->pipe = NULL;
262 }
263
264 mutex_unlock(&mdev->graph_mutex);
265}
266EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
267
268/* -----------------------------------------------------------------------------
Laurent Pinchart503c3d82010-03-07 15:04:59 -0300269 * Module use count
270 */
271
272/*
273 * media_entity_get - Get a reference to the parent module
274 * @entity: The entity
275 *
276 * Get a reference to the parent media device module.
277 *
278 * The function will return immediately if @entity is NULL.
279 *
280 * Return a pointer to the entity on success or NULL on failure.
281 */
282struct media_entity *media_entity_get(struct media_entity *entity)
283{
284 if (entity == NULL)
285 return NULL;
286
287 if (entity->parent->dev &&
288 !try_module_get(entity->parent->dev->driver->owner))
289 return NULL;
290
291 return entity;
292}
293EXPORT_SYMBOL_GPL(media_entity_get);
294
295/*
296 * media_entity_put - Release the reference to the parent module
297 * @entity: The entity
298 *
299 * Release the reference count acquired by media_entity_get().
300 *
301 * The function will return immediately if @entity is NULL.
302 */
303void media_entity_put(struct media_entity *entity)
304{
305 if (entity == NULL)
306 return;
307
308 if (entity->parent->dev)
309 module_put(entity->parent->dev->driver->owner);
310}
311EXPORT_SYMBOL_GPL(media_entity_put);
312
313/* -----------------------------------------------------------------------------
Sakari Ailusa5ccc482010-03-07 16:14:14 -0300314 * Links management
315 */
316
Laurent Pinchart53e269c2009-12-09 08:40:00 -0300317static struct media_link *media_entity_add_link(struct media_entity *entity)
318{
319 if (entity->num_links >= entity->max_links) {
320 struct media_link *links = entity->links;
321 unsigned int max_links = entity->max_links + 2;
322 unsigned int i;
323
324 links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
325 if (links == NULL)
326 return NULL;
327
328 for (i = 0; i < entity->num_links; i++)
329 links[i].reverse->reverse = &links[i];
330
331 entity->max_links = max_links;
332 entity->links = links;
333 }
334
335 return &entity->links[entity->num_links++];
336}
337
338int
339media_entity_create_link(struct media_entity *source, u16 source_pad,
340 struct media_entity *sink, u16 sink_pad, u32 flags)
341{
342 struct media_link *link;
343 struct media_link *backlink;
344
345 BUG_ON(source == NULL || sink == NULL);
346 BUG_ON(source_pad >= source->num_pads);
347 BUG_ON(sink_pad >= sink->num_pads);
348
349 link = media_entity_add_link(source);
350 if (link == NULL)
351 return -ENOMEM;
352
353 link->source = &source->pads[source_pad];
354 link->sink = &sink->pads[sink_pad];
355 link->flags = flags;
356
357 /* Create the backlink. Backlinks are used to help graph traversal and
358 * are not reported to userspace.
359 */
360 backlink = media_entity_add_link(sink);
361 if (backlink == NULL) {
362 source->num_links--;
363 return -ENOMEM;
364 }
365
366 backlink->source = &source->pads[source_pad];
367 backlink->sink = &sink->pads[sink_pad];
368 backlink->flags = flags;
369
370 link->reverse = backlink;
371 backlink->reverse = link;
372
373 sink->num_backlinks++;
374
375 return 0;
376}
377EXPORT_SYMBOL_GPL(media_entity_create_link);
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300378
379static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
380{
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300381 int ret;
382
383 /* Notify both entities. */
384 ret = media_entity_call(link->source->entity, link_setup,
385 link->source, link->sink, flags);
386 if (ret < 0 && ret != -ENOIOCTLCMD)
387 return ret;
388
389 ret = media_entity_call(link->sink->entity, link_setup,
390 link->sink, link->source, flags);
391 if (ret < 0 && ret != -ENOIOCTLCMD) {
392 media_entity_call(link->source->entity, link_setup,
393 link->source, link->sink, link->flags);
394 return ret;
395 }
396
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300397 link->flags = flags;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300398 link->reverse->flags = link->flags;
399
400 return 0;
401}
402
403/**
404 * __media_entity_setup_link - Configure a media link
405 * @link: The link being configured
406 * @flags: Link configuration flags
407 *
408 * The bulk of link setup is handled by the two entities connected through the
409 * link. This function notifies both entities of the link configuration change.
410 *
411 * If the link is immutable or if the current and new configuration are
412 * identical, return immediately.
413 *
414 * The user is expected to hold link->source->parent->mutex. If not,
415 * media_entity_setup_link() should be used instead.
416 */
417int __media_entity_setup_link(struct media_link *link, u32 flags)
418{
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300419 const u32 mask = MEDIA_LNK_FL_ENABLED;
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300420 struct media_device *mdev;
421 struct media_entity *source, *sink;
422 int ret = -EBUSY;
423
424 if (link == NULL)
425 return -EINVAL;
426
Laurent Pinchart7a6f0b22011-03-11 11:34:35 -0300427 /* The non-modifiable link flags must not be modified. */
428 if ((link->flags & ~mask) != (flags & ~mask))
429 return -EINVAL;
430
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300431 if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
432 return link->flags == flags ? 0 : -EINVAL;
433
434 if (link->flags == flags)
435 return 0;
436
437 source = link->source->entity;
438 sink = link->sink->entity;
439
Laurent Pincharte02188c2010-08-25 09:00:41 -0300440 if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
441 (source->stream_count || sink->stream_count))
442 return -EBUSY;
443
Laurent Pinchart97548ed2009-12-09 08:40:03 -0300444 mdev = source->parent;
445
446 if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) {
447 ret = mdev->link_notify(link->source, link->sink,
448 MEDIA_LNK_FL_ENABLED);
449 if (ret < 0)
450 return ret;
451 }
452
453 ret = __media_entity_setup_link_notify(link, flags);
454 if (ret < 0)
455 goto err;
456
457 if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
458 mdev->link_notify(link->source, link->sink, 0);
459
460 return 0;
461
462err:
463 if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
464 mdev->link_notify(link->source, link->sink, 0);
465
466 return ret;
467}
468
469int media_entity_setup_link(struct media_link *link, u32 flags)
470{
471 int ret;
472
473 mutex_lock(&link->source->entity->parent->graph_mutex);
474 ret = __media_entity_setup_link(link, flags);
475 mutex_unlock(&link->source->entity->parent->graph_mutex);
476
477 return ret;
478}
479EXPORT_SYMBOL_GPL(media_entity_setup_link);
480
481/**
482 * media_entity_find_link - Find a link between two pads
483 * @source: Source pad
484 * @sink: Sink pad
485 *
486 * Return a pointer to the link between the two entities. If no such link
487 * exists, return NULL.
488 */
489struct media_link *
490media_entity_find_link(struct media_pad *source, struct media_pad *sink)
491{
492 struct media_link *link;
493 unsigned int i;
494
495 for (i = 0; i < source->entity->num_links; ++i) {
496 link = &source->entity->links[i];
497
498 if (link->source->entity == source->entity &&
499 link->source->index == source->index &&
500 link->sink->entity == sink->entity &&
501 link->sink->index == sink->index)
502 return link;
503 }
504
505 return NULL;
506}
507EXPORT_SYMBOL_GPL(media_entity_find_link);
508
509/**
510 * media_entity_remote_source - Find the source pad at the remote end of a link
511 * @pad: Sink pad at the local end of the link
512 *
513 * Search for a remote source pad connected to the given sink pad by iterating
514 * over all links originating or terminating at that pad until an enabled link
515 * is found.
516 *
517 * Return a pointer to the pad at the remote end of the first found enabled
518 * link, or NULL if no enabled link has been found.
519 */
520struct media_pad *media_entity_remote_source(struct media_pad *pad)
521{
522 unsigned int i;
523
524 for (i = 0; i < pad->entity->num_links; i++) {
525 struct media_link *link = &pad->entity->links[i];
526
527 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
528 continue;
529
530 if (link->source == pad)
531 return link->sink;
532
533 if (link->sink == pad)
534 return link->source;
535 }
536
537 return NULL;
538
539}
540EXPORT_SYMBOL_GPL(media_entity_remote_source);