[media] media-entitiy: add a function to create multiple links

Sometimes, it is desired to create 1:n and n:1 or even
n:n links between different entities with the same
function.

This is actually needed to support DVB devices that
have multiple frontends. While we could do a function
like that internally at the DVB core, such function is
generic enough to be at media-entity, and it could be
useful on some other places.

So, add such function.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Mauro Carvalho Chehab 2015-12-30 09:45:48 -02:00
parent 33c6853347
commit b01cc9ce7c
2 changed files with 116 additions and 0 deletions

View file

@ -625,6 +625,71 @@ media_create_pad_link(struct media_entity *source, u16 source_pad,
}
EXPORT_SYMBOL_GPL(media_create_pad_link);
int media_create_pad_links(const struct media_device *mdev,
const u32 source_function,
struct media_entity *source,
const u16 source_pad,
const u32 sink_function,
struct media_entity *sink,
const u16 sink_pad,
u32 flags,
const bool allow_both_undefined)
{
struct media_entity *entity;
unsigned function;
int ret;
/* Trivial case: 1:1 relation */
if (source && sink)
return media_create_pad_link(source, source_pad,
sink, sink_pad, flags);
/* Worse case scenario: n:n relation */
if (!source && !sink) {
if (!allow_both_undefined)
return 0;
media_device_for_each_entity(source, mdev) {
if (source->function != source_function)
continue;
media_device_for_each_entity(sink, mdev) {
if (sink->function != sink_function)
continue;
ret = media_create_pad_link(source, source_pad,
sink, sink_pad,
flags);
if (ret)
return ret;
flags &= ~(MEDIA_LNK_FL_ENABLED |
MEDIA_LNK_FL_IMMUTABLE);
}
}
return 0;
}
/* Handle 1:n and n:1 cases */
if (source)
function = sink_function;
else
function = source_function;
media_device_for_each_entity(entity, mdev) {
if (entity->function != function)
continue;
if (source)
ret = media_create_pad_link(source, source_pad,
entity, sink_pad, flags);
else
ret = media_create_pad_link(entity, source_pad,
sink, sink_pad, flags);
if (ret)
return ret;
flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
}
return 0;
}
EXPORT_SYMBOL_GPL(media_create_pad_links);
void __media_entity_remove_links(struct media_entity *entity)
{
struct media_link *link, *tmp;

View file

@ -613,6 +613,57 @@ static inline void media_entity_cleanup(struct media_entity *entity) {};
__must_check int media_create_pad_link(struct media_entity *source,
u16 source_pad, struct media_entity *sink,
u16 sink_pad, u32 flags);
/**
* media_create_pad_links() - creates a link between two entities.
*
* @mdev: Pointer to the media_device that contains the object
* @source_function: Function of the source entities. Used only if @source is
* NULL.
* @source: pointer to &media_entity of the source pad. If NULL, it will use
* all entities that matches the @sink_function.
* @source_pad: number of the source pad in the pads array
* @sink_function: Function of the sink entities. Used only if @sink is NULL.
* @sink: pointer to &media_entity of the sink pad. If NULL, it will use
* all entities that matches the @sink_function.
* @sink_pad: number of the sink pad in the pads array.
* @flags: Link flags, as defined in include/uapi/linux/media.h.
* @allow_both_undefined: if true, then both @source and @sink can be NULL.
* In such case, it will create a crossbar between all entities that
* matches @source_function to all entities that matches @sink_function.
* If false, it will return 0 and won't create any link if both @source
* and @sink are NULL.
*
* Valid values for flags:
* A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
* used to transfer media data. If multiple links are created and this
* flag is passed as an argument, only the first created link will have
* this flag.
*
* A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
* be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
* %MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
* always enabled.
*
* It is common for some devices to have multiple source and/or sink entities
* of the same type that should be linked. While media_create_pad_link()
* creates link by link, this function is meant to allow 1:n, n:1 and even
* cross-bar (n:n) links.
*
* NOTE: Before calling this function, media_entity_pads_init() and
* media_device_register_entity() should be called previously for the entities
* to be linked.
*/
int media_create_pad_links(const struct media_device *mdev,
const u32 source_function,
struct media_entity *source,
const u16 source_pad,
const u32 sink_function,
struct media_entity *sink,
const u16 sink_pad,
u32 flags,
const bool allow_both_undefined);
void __media_entity_remove_links(struct media_entity *entity);
/**