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Commit b01cc9ce authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

[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: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 33c68533

drivers/media/media-entity.c

+65 −0
Original line number Diff line number Diff line
@@ -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;

include/media/media-entity.h

+51 −0
Original line number Diff line number Diff line
@@ -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);



/**