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@xxxxxxxxxxxxxxx>
---
drivers/media/media-entity.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
include/media/media-entity.h | 51 ++++++++++++++++++++++++++++++++++
2 files changed, 116 insertions(+)
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index eb38bc35320a..e89d85a7d31b 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -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;
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 79dd81fd463e..fe485d367985 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -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);
/**
--
2.5.0
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