Root/drivers/media/media-entity.c

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>
26#include <media/media-device.h>
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 */
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
88/* -----------------------------------------------------------------------------
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/* -----------------------------------------------------------------------------
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__must_check int 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    struct media_entity *entity_err = entity;
223    int ret;
224
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))) {
230        unsigned int i;
231
232        entity->stream_count++;
233        WARN_ON(entity->pipe && entity->pipe != pipe);
234        entity->pipe = pipe;
235
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        }
258    }
259
260    mutex_unlock(&mdev->graph_mutex);
261
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;
287}
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/* -----------------------------------------------------------------------------
322 * 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/* -----------------------------------------------------------------------------
367 * Links management
368 */
369
370static 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);
431
432static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
433{
434    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
450    link->flags = flags;
451    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{
472    const u32 mask = MEDIA_LNK_FL_ENABLED;
473    struct media_device *mdev;
474    struct media_entity *source, *sink;
475    int ret = -EBUSY;
476
477    if (link == NULL)
478        return -EINVAL;
479
480    /* The non-modifiable link flags must not be modified. */
481    if ((link->flags & ~mask) != (flags & ~mask))
482        return -EINVAL;
483
484    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
493    if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
494        (source->stream_count || sink->stream_count))
495        return -EBUSY;
496
497    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);
594

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive