summaryrefslogtreecommitdiffstats
path: root/drivers/media/media-entity.c
blob: 6795c920d460d74b11db9f33b6c9272f811b316d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
/*
 * Media entity
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *	     Sakari Ailus <sakari.ailus@iki.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <media/media-entity.h>
#include <media/media-device.h>

/**
 * media_entity_init - Initialize a media entity
 *
 * @num_pads: Total number of sink and source pads.
 * @extra_links: Initial estimate of the number of extra links.
 * @pads: Array of 'num_pads' pads.
 *
 * The total number of pads is an intrinsic property of entities known by the
 * entity driver, while the total number of links depends on hardware design
 * and is an extrinsic property unknown to the entity driver. However, in most
 * use cases the entity driver can guess the number of links which can safely
 * be assumed to be equal to or larger than the number of pads.
 *
 * For those reasons the links array can be preallocated based on the entity
 * driver guess and will be reallocated later if extra links need to be
 * created.
 *
 * This function allocates a links array with enough space to hold at least
 * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
 * be set to the number of allocated elements.
 *
 * The pads array is managed by the entity driver and passed to
 * media_entity_init() where its pointer will be stored in the entity structure.
 */
int
media_entity_init(struct media_entity *entity, u16 num_pads,
		  struct media_pad *pads, u16 extra_links)
{
	struct media_link *links;
	unsigned int max_links = num_pads + extra_links;
	unsigned int i;

	links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
	if (links == NULL)
		return -ENOMEM;

	entity->group_id = 0;
	entity->max_links = max_links;
	entity->num_links = 0;
	entity->num_backlinks = 0;
	entity->num_pads = num_pads;
	entity->pads = pads;
	entity->links = links;

	for (i = 0; i < num_pads; i++) {
		pads[i].entity = entity;
		pads[i].index = i;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(media_entity_init);

void
media_entity_cleanup(struct media_entity *entity)
{
	kfree(entity->links);
}
EXPORT_SYMBOL_GPL(media_entity_cleanup);

/* -----------------------------------------------------------------------------
 * Graph traversal
 */

static struct media_entity *
media_entity_other(struct media_entity *entity, struct media_link *link)
{
	if (link->source->entity == entity)
		return link->sink->entity;
	else
		return link->source->entity;
}

/* push an entity to traversal stack */
static void stack_push(struct media_entity_graph *graph,
		       struct media_entity *entity)
{
	if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
		WARN_ON(1);
		return;
	}
	graph->top++;
	graph->stack[graph->top].link = 0;
	graph->stack[graph->top].entity = entity;
}

static struct media_entity *stack_pop(struct media_entity_graph *graph)
{
	struct media_entity *entity;

	entity = graph->stack[graph->top].entity;
	graph->top--;

	return entity;
}

#define stack_peek(en)	((en)->stack[(en)->top - 1].entity)
#define link_top(en)	((en)->stack[(en)->top].link)
#define stack_top(en)	((en)->stack[(en)->top].entity)

/**
 * media_entity_graph_walk_start - Start walking the media graph at a given entity
 * @graph: Media graph structure that will be used to walk the graph
 * @entity: Starting entity
 *
 * This function initializes the graph traversal structure to walk the entities
 * graph starting at the given entity. The traversal structure must not be
 * modified by the caller during graph traversal. When done the structure can
 * safely be freed.
 */
void media_entity_graph_walk_start(struct media_entity_graph *graph,
				   struct media_entity *entity)
{
	graph->top = 0;
	graph->stack[graph->top].entity = NULL;
	stack_push(graph, entity);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);

/**
 * media_entity_graph_walk_next - Get the next entity in the graph
 * @graph: Media graph structure
 *
 * Perform a depth-first traversal of the given media entities graph.
 *
 * The graph structure must have been previously initialized with a call to
 * media_entity_graph_walk_start().
 *
 * Return the next entity in the graph or NULL if the whole graph have been
 * traversed.
 */
struct media_entity *
media_entity_graph_walk_next(struct media_entity_graph *graph)
{
	if (stack_top(graph) == NULL)
		return NULL;

	/*
	 * Depth first search. Push entity to stack and continue from
	 * top of the stack until no more entities on the level can be
	 * found.
	 */
	while (link_top(graph) < stack_top(graph)->num_links) {
		struct media_entity *entity = stack_top(graph);
		struct media_link *link = &entity->links[link_top(graph)];
		struct media_entity *next;

		/* The link is not enabled so we do not follow. */
		if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
			link_top(graph)++;
			continue;
		}

		/* Get the entity in the other end of the link . */
		next = media_entity_other(entity, link);

		/* Was it the entity we came here from? */
		if (next == stack_peek(graph)) {
			link_top(graph)++;
			continue;
		}

		/* Push the new entity to stack and start over. */
		link_top(graph)++;
		stack_push(graph, next);
	}

	return stack_pop(graph);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);

/* -----------------------------------------------------------------------------
 * Module use count
 */

/*
 * media_entity_get - Get a reference to the parent module
 * @entity: The entity
 *
 * Get a reference to the parent media device module.
 *
 * The function will return immediately if @entity is NULL.
 *
 * Return a pointer to the entity on success or NULL on failure.
 */
struct media_entity *media_entity_get(struct media_entity *entity)
{
	if (entity == NULL)
		return NULL;

	if (entity->parent->dev &&
	    !try_module_get(entity->parent->dev->driver->owner))
		return NULL;

	return entity;
}
EXPORT_SYMBOL_GPL(media_entity_get);

/*
 * media_entity_put - Release the reference to the parent module
 * @entity: The entity
 *
 * Release the reference count acquired by media_entity_get().
 *
 * The function will return immediately if @entity is NULL.
 */
void media_entity_put(struct media_entity *entity)
{
	if (entity == NULL)
		return;

	if (entity->parent->dev)
		module_put(entity->parent->dev->driver->owner);
}
EXPORT_SYMBOL_GPL(media_entity_put);

/* -----------------------------------------------------------------------------
 * Links management
 */

static struct media_link *media_entity_add_link(struct media_entity *entity)
{
	if (entity->num_links >= entity->max_links) {
		struct media_link *links = entity->links;
		unsigned int max_links = entity->max_links + 2;
		unsigned int i;

		links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
		if (links == NULL)
			return NULL;

		for (i = 0; i < entity->num_links; i++)
			links[i].reverse->reverse = &links[i];

		entity->max_links = max_links;
		entity->links = links;
	}

	return &entity->links[entity->num_links++];
}

int
media_entity_create_link(struct media_entity *source, u16 source_pad,
			 struct media_entity *sink, u16 sink_pad, u32 flags)
{
	struct media_link *link;
	struct media_link *backlink;

	BUG_ON(source == NULL || sink == NULL);
	BUG_ON(source_pad >= source->num_pads);
	BUG_ON(sink_pad >= sink->num_pads);

	link = media_entity_add_link(source);
	if (link == NULL)
		return -ENOMEM;

	link->source = &source->pads[source_pad];
	link->sink = &sink->pads[sink_pad];
	link->flags = flags;

	/* Create the backlink. Backlinks are used to help graph traversal and
	 * are not reported to userspace.
	 */
	backlink = media_entity_add_link(sink);
	if (backlink == NULL) {
		source->num_links--;
		return -ENOMEM;
	}

	backlink->source = &source->pads[source_pad];
	backlink->sink = &sink->pads[sink_pad];
	backlink->flags = flags;

	link->reverse = backlink;
	backlink->reverse = link;

	sink->num_backlinks++;

	return 0;
}
EXPORT_SYMBOL_GPL(media_entity_create_link);

static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
{
	const u32 mask = MEDIA_LNK_FL_ENABLED;
	int ret;

	/* Notify both entities. */
	ret = media_entity_call(link->source->entity, link_setup,
				link->source, link->sink, flags);
	if (ret < 0 && ret != -ENOIOCTLCMD)
		return ret;

	ret = media_entity_call(link->sink->entity, link_setup,
				link->sink, link->source, flags);
	if (ret < 0 && ret != -ENOIOCTLCMD) {
		media_entity_call(link->source->entity, link_setup,
				  link->source, link->sink, link->flags);
		return ret;
	}

	link->flags = (link->flags & ~mask) | (flags & mask);
	link->reverse->flags = link->flags;

	return 0;
}

/**
 * __media_entity_setup_link - Configure a media link
 * @link: The link being configured
 * @flags: Link configuration flags
 *
 * The bulk of link setup is handled by the two entities connected through the
 * link. This function notifies both entities of the link configuration change.
 *
 * If the link is immutable or if the current and new configuration are
 * identical, return immediately.
 *
 * The user is expected to hold link->source->parent->mutex. If not,
 * media_entity_setup_link() should be used instead.
 */
int __media_entity_setup_link(struct media_link *link, u32 flags)
{
	struct media_device *mdev;
	struct media_entity *source, *sink;
	int ret = -EBUSY;

	if (link == NULL)
		return -EINVAL;

	if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
		return link->flags == flags ? 0 : -EINVAL;

	if (link->flags == flags)
		return 0;

	source = link->source->entity;
	sink = link->sink->entity;

	mdev = source->parent;

	if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) {
		ret = mdev->link_notify(link->source, link->sink,
					MEDIA_LNK_FL_ENABLED);
		if (ret < 0)
			return ret;
	}

	ret = __media_entity_setup_link_notify(link, flags);
	if (ret < 0)
		goto err;

	if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
		mdev->link_notify(link->source, link->sink, 0);

	return 0;

err:
	if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
		mdev->link_notify(link->source, link->sink, 0);

	return ret;
}

int media_entity_setup_link(struct media_link *link, u32 flags)
{
	int ret;

	mutex_lock(&link->source->entity->parent->graph_mutex);
	ret = __media_entity_setup_link(link, flags);
	mutex_unlock(&link->source->entity->parent->graph_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(media_entity_setup_link);

/**
 * media_entity_find_link - Find a link between two pads
 * @source: Source pad
 * @sink: Sink pad
 *
 * Return a pointer to the link between the two entities. If no such link
 * exists, return NULL.
 */
struct media_link *
media_entity_find_link(struct media_pad *source, struct media_pad *sink)
{
	struct media_link *link;
	unsigned int i;

	for (i = 0; i < source->entity->num_links; ++i) {
		link = &source->entity->links[i];

		if (link->source->entity == source->entity &&
		    link->source->index == source->index &&
		    link->sink->entity == sink->entity &&
		    link->sink->index == sink->index)
			return link;
	}

	return NULL;
}
EXPORT_SYMBOL_GPL(media_entity_find_link);

/**
 * media_entity_remote_source - Find the source pad at the remote end of a link
 * @pad: Sink pad at the local end of the link
 *
 * Search for a remote source pad connected to the given sink pad by iterating
 * over all links originating or terminating at that pad until an enabled link
 * is found.
 *
 * Return a pointer to the pad at the remote end of the first found enabled
 * link, or NULL if no enabled link has been found.
 */
struct media_pad *media_entity_remote_source(struct media_pad *pad)
{
	unsigned int i;

	for (i = 0; i < pad->entity->num_links; i++) {
		struct media_link *link = &pad->entity->links[i];

		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
			continue;

		if (link->source == pad)
			return link->sink;

		if (link->sink == pad)
			return link->source;
	}

	return NULL;

}
EXPORT_SYMBOL_GPL(media_entity_remote_source);
OpenPOWER on IntegriCloud