4 * Copyright (C) 2010 Nokia Corporation
6 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
7 * Sakari Ailus <sakari.ailus@iki.fi>
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.
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.
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
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <media/media-entity.h>
26 #include <media/media-device.h>
29 * media_entity_init - Initialize a media entity
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.
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.
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
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.
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.
53 media_entity_init(struct media_entity
*entity
, u16 num_pads
,
54 struct media_pad
*pads
, u16 extra_links
)
56 struct media_link
*links
;
57 unsigned int max_links
= num_pads
+ extra_links
;
60 links
= kzalloc(max_links
* sizeof(links
[0]), GFP_KERNEL
);
65 entity
->max_links
= max_links
;
66 entity
->num_links
= 0;
67 entity
->num_backlinks
= 0;
68 entity
->num_pads
= num_pads
;
70 entity
->links
= links
;
72 for (i
= 0; i
< num_pads
; i
++) {
73 pads
[i
].entity
= entity
;
79 EXPORT_SYMBOL_GPL(media_entity_init
);
82 media_entity_cleanup(struct media_entity
*entity
)
86 EXPORT_SYMBOL_GPL(media_entity_cleanup
);
88 /* -----------------------------------------------------------------------------
92 static struct media_entity
*
93 media_entity_other(struct media_entity
*entity
, struct media_link
*link
)
95 if (link
->source
->entity
== entity
)
96 return link
->sink
->entity
;
98 return link
->source
->entity
;
101 /* push an entity to traversal stack */
102 static void stack_push(struct media_entity_graph
*graph
,
103 struct media_entity
*entity
)
105 if (graph
->top
== MEDIA_ENTITY_ENUM_MAX_DEPTH
- 1) {
110 graph
->stack
[graph
->top
].link
= 0;
111 graph
->stack
[graph
->top
].entity
= entity
;
114 static struct media_entity
*stack_pop(struct media_entity_graph
*graph
)
116 struct media_entity
*entity
;
118 entity
= graph
->stack
[graph
->top
].entity
;
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)
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
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
138 void media_entity_graph_walk_start(struct media_entity_graph
*graph
,
139 struct media_entity
*entity
)
142 graph
->stack
[graph
->top
].entity
= NULL
;
143 stack_push(graph
, entity
);
145 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start
);
148 * media_entity_graph_walk_next - Get the next entity in the graph
149 * @graph: Media graph structure
151 * Perform a depth-first traversal of the given media entities graph.
153 * The graph structure must have been previously initialized with a call to
154 * media_entity_graph_walk_start().
156 * Return the next entity in the graph or NULL if the whole graph have been
159 struct media_entity
*
160 media_entity_graph_walk_next(struct media_entity_graph
*graph
)
162 if (stack_top(graph
) == NULL
)
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
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
;
175 /* The link is not enabled so we do not follow. */
176 if (!(link
->flags
& MEDIA_LNK_FL_ENABLED
)) {
181 /* Get the entity in the other end of the link . */
182 next
= media_entity_other(entity
, link
);
184 /* Was it the entity we came here from? */
185 if (next
== stack_peek(graph
)) {
190 /* Push the new entity to stack and start over. */
192 stack_push(graph
, next
);
195 return stack_pop(graph
);
197 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next
);
199 /* -----------------------------------------------------------------------------
204 * media_entity_get - Get a reference to the parent module
205 * @entity: The entity
207 * Get a reference to the parent media device module.
209 * The function will return immediately if @entity is NULL.
211 * Return a pointer to the entity on success or NULL on failure.
213 struct media_entity
*media_entity_get(struct media_entity
*entity
)
218 if (entity
->parent
->dev
&&
219 !try_module_get(entity
->parent
->dev
->driver
->owner
))
224 EXPORT_SYMBOL_GPL(media_entity_get
);
227 * media_entity_put - Release the reference to the parent module
228 * @entity: The entity
230 * Release the reference count acquired by media_entity_get().
232 * The function will return immediately if @entity is NULL.
234 void media_entity_put(struct media_entity
*entity
)
239 if (entity
->parent
->dev
)
240 module_put(entity
->parent
->dev
->driver
->owner
);
242 EXPORT_SYMBOL_GPL(media_entity_put
);
244 /* -----------------------------------------------------------------------------
248 static struct media_link
*media_entity_add_link(struct media_entity
*entity
)
250 if (entity
->num_links
>= entity
->max_links
) {
251 struct media_link
*links
= entity
->links
;
252 unsigned int max_links
= entity
->max_links
+ 2;
255 links
= krealloc(links
, max_links
* sizeof(*links
), GFP_KERNEL
);
259 for (i
= 0; i
< entity
->num_links
; i
++)
260 links
[i
].reverse
->reverse
= &links
[i
];
262 entity
->max_links
= max_links
;
263 entity
->links
= links
;
266 return &entity
->links
[entity
->num_links
++];
270 media_entity_create_link(struct media_entity
*source
, u16 source_pad
,
271 struct media_entity
*sink
, u16 sink_pad
, u32 flags
)
273 struct media_link
*link
;
274 struct media_link
*backlink
;
276 BUG_ON(source
== NULL
|| sink
== NULL
);
277 BUG_ON(source_pad
>= source
->num_pads
);
278 BUG_ON(sink_pad
>= sink
->num_pads
);
280 link
= media_entity_add_link(source
);
284 link
->source
= &source
->pads
[source_pad
];
285 link
->sink
= &sink
->pads
[sink_pad
];
288 /* Create the backlink. Backlinks are used to help graph traversal and
289 * are not reported to userspace.
291 backlink
= media_entity_add_link(sink
);
292 if (backlink
== NULL
) {
297 backlink
->source
= &source
->pads
[source_pad
];
298 backlink
->sink
= &sink
->pads
[sink_pad
];
299 backlink
->flags
= flags
;
301 link
->reverse
= backlink
;
302 backlink
->reverse
= link
;
304 sink
->num_backlinks
++;
308 EXPORT_SYMBOL_GPL(media_entity_create_link
);
310 static int __media_entity_setup_link_notify(struct media_link
*link
, u32 flags
)
312 const u32 mask
= MEDIA_LNK_FL_ENABLED
;
315 /* Notify both entities. */
316 ret
= media_entity_call(link
->source
->entity
, link_setup
,
317 link
->source
, link
->sink
, flags
);
318 if (ret
< 0 && ret
!= -ENOIOCTLCMD
)
321 ret
= media_entity_call(link
->sink
->entity
, link_setup
,
322 link
->sink
, link
->source
, flags
);
323 if (ret
< 0 && ret
!= -ENOIOCTLCMD
) {
324 media_entity_call(link
->source
->entity
, link_setup
,
325 link
->source
, link
->sink
, link
->flags
);
329 link
->flags
= (link
->flags
& ~mask
) | (flags
& mask
);
330 link
->reverse
->flags
= link
->flags
;
336 * __media_entity_setup_link - Configure a media link
337 * @link: The link being configured
338 * @flags: Link configuration flags
340 * The bulk of link setup is handled by the two entities connected through the
341 * link. This function notifies both entities of the link configuration change.
343 * If the link is immutable or if the current and new configuration are
344 * identical, return immediately.
346 * The user is expected to hold link->source->parent->mutex. If not,
347 * media_entity_setup_link() should be used instead.
349 int __media_entity_setup_link(struct media_link
*link
, u32 flags
)
351 struct media_device
*mdev
;
352 struct media_entity
*source
, *sink
;
358 if (link
->flags
& MEDIA_LNK_FL_IMMUTABLE
)
359 return link
->flags
== flags
? 0 : -EINVAL
;
361 if (link
->flags
== flags
)
364 source
= link
->source
->entity
;
365 sink
= link
->sink
->entity
;
367 mdev
= source
->parent
;
369 if ((flags
& MEDIA_LNK_FL_ENABLED
) && mdev
->link_notify
) {
370 ret
= mdev
->link_notify(link
->source
, link
->sink
,
371 MEDIA_LNK_FL_ENABLED
);
376 ret
= __media_entity_setup_link_notify(link
, flags
);
380 if (!(flags
& MEDIA_LNK_FL_ENABLED
) && mdev
->link_notify
)
381 mdev
->link_notify(link
->source
, link
->sink
, 0);
386 if ((flags
& MEDIA_LNK_FL_ENABLED
) && mdev
->link_notify
)
387 mdev
->link_notify(link
->source
, link
->sink
, 0);
392 int media_entity_setup_link(struct media_link
*link
, u32 flags
)
396 mutex_lock(&link
->source
->entity
->parent
->graph_mutex
);
397 ret
= __media_entity_setup_link(link
, flags
);
398 mutex_unlock(&link
->source
->entity
->parent
->graph_mutex
);
402 EXPORT_SYMBOL_GPL(media_entity_setup_link
);
405 * media_entity_find_link - Find a link between two pads
406 * @source: Source pad
409 * Return a pointer to the link between the two entities. If no such link
410 * exists, return NULL.
413 media_entity_find_link(struct media_pad
*source
, struct media_pad
*sink
)
415 struct media_link
*link
;
418 for (i
= 0; i
< source
->entity
->num_links
; ++i
) {
419 link
= &source
->entity
->links
[i
];
421 if (link
->source
->entity
== source
->entity
&&
422 link
->source
->index
== source
->index
&&
423 link
->sink
->entity
== sink
->entity
&&
424 link
->sink
->index
== sink
->index
)
430 EXPORT_SYMBOL_GPL(media_entity_find_link
);
433 * media_entity_remote_source - Find the source pad at the remote end of a link
434 * @pad: Sink pad at the local end of the link
436 * Search for a remote source pad connected to the given sink pad by iterating
437 * over all links originating or terminating at that pad until an enabled link
440 * Return a pointer to the pad at the remote end of the first found enabled
441 * link, or NULL if no enabled link has been found.
443 struct media_pad
*media_entity_remote_source(struct media_pad
*pad
)
447 for (i
= 0; i
< pad
->entity
->num_links
; i
++) {
448 struct media_link
*link
= &pad
->entity
->links
[i
];
450 if (!(link
->flags
& MEDIA_LNK_FL_ENABLED
))
453 if (link
->source
== pad
)
456 if (link
->sink
== pad
)
463 EXPORT_SYMBOL_GPL(media_entity_remote_source
);