Commit | Line | Data |
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53e269c1 LP |
1 | /* |
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> | |
503c3d82 | 26 | #include <media/media-device.h> |
53e269c1 LP |
27 | |
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 | */ | |
52 | int | |
53 | media_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 | } | |
79 | EXPORT_SYMBOL_GPL(media_entity_init); | |
80 | ||
81 | void | |
82 | media_entity_cleanup(struct media_entity *entity) | |
83 | { | |
84 | kfree(entity->links); | |
85 | } | |
86 | EXPORT_SYMBOL_GPL(media_entity_cleanup); | |
87 | ||
a5ccc48a SA |
88 | /* ----------------------------------------------------------------------------- |
89 | * Graph traversal | |
90 | */ | |
91 | ||
92 | static struct media_entity * | |
93 | media_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 */ | |
102 | static 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 | ||
114 | static 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 | */ | |
138 | void 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 | } | |
145 | EXPORT_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 | */ | |
159 | struct media_entity * | |
160 | media_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 | } | |
197 | EXPORT_SYMBOL_GPL(media_entity_graph_walk_next); | |
198 | ||
e02188c9 LP |
199 | /* ----------------------------------------------------------------------------- |
200 | * 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 | */ | |
217 | void 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 | } | |
235 | EXPORT_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 | */ | |
249 | void 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 | } | |
266 | EXPORT_SYMBOL_GPL(media_entity_pipeline_stop); | |
267 | ||
503c3d82 LP |
268 | /* ----------------------------------------------------------------------------- |
269 | * 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 | */ | |
282 | struct 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 | } | |
293 | EXPORT_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 | */ | |
303 | void 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 | } | |
311 | EXPORT_SYMBOL_GPL(media_entity_put); | |
312 | ||
a5ccc48a SA |
313 | /* ----------------------------------------------------------------------------- |
314 | * Links management | |
315 | */ | |
316 | ||
53e269c1 LP |
317 | static 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 | ||
338 | int | |
339 | media_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 | } | |
377 | EXPORT_SYMBOL_GPL(media_entity_create_link); | |
97548ed4 LP |
378 | |
379 | static int __media_entity_setup_link_notify(struct media_link *link, u32 flags) | |
380 | { | |
97548ed4 LP |
381 | 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 | ||
7a6f0b22 | 397 | link->flags = flags; |
97548ed4 LP |
398 | 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 | */ | |
417 | int __media_entity_setup_link(struct media_link *link, u32 flags) | |
418 | { | |
7a6f0b22 | 419 | const u32 mask = MEDIA_LNK_FL_ENABLED; |
97548ed4 LP |
420 | struct media_device *mdev; |
421 | struct media_entity *source, *sink; | |
422 | int ret = -EBUSY; | |
423 | ||
424 | if (link == NULL) | |
425 | return -EINVAL; | |
426 | ||
7a6f0b22 LP |
427 | /* The non-modifiable link flags must not be modified. */ |
428 | if ((link->flags & ~mask) != (flags & ~mask)) | |
429 | return -EINVAL; | |
430 | ||
97548ed4 LP |
431 | 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 | ||
e02188c9 LP |
440 | if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) && |
441 | (source->stream_count || sink->stream_count)) | |
442 | return -EBUSY; | |
443 | ||
97548ed4 LP |
444 | 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 | ||
462 | err: | |
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 | ||
469 | int 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 | } | |
479 | EXPORT_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 | */ | |
489 | struct media_link * | |
490 | media_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 | } | |
507 | EXPORT_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 | */ | |
520 | struct 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 | } | |
540 | EXPORT_SYMBOL_GPL(media_entity_remote_source); |