On 03/10/2023 13:52, Sakari Ailus wrote:
> Internal source pads will be used as routing endpoints in V4L2
> [GS]_ROUTING IOCTLs, to indicate that the stream begins in the entity.
>
> Also prevent creating links to pads that have been flagged as internal and
> initialising source pads with internal flag set.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> Documentation/userspace-api/media/glossary.rst | 6 ++++++
> .../userspace-api/media/mediactl/media-types.rst | 6 ++++++
> drivers/media/mc/mc-entity.c | 10 ++++++++--
> include/uapi/linux/media.h | 1 +
> 4 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/glossary.rst b/Documentation/userspace-api/media/glossary.rst
> index 96a360edbf3b..f7b99a4527c7 100644
> --- a/Documentation/userspace-api/media/glossary.rst
> +++ b/Documentation/userspace-api/media/glossary.rst
> @@ -173,6 +173,12 @@ Glossary
> An integrated circuit that integrates all components of a computer
> or other electronic systems.
>
> +_media-glossary-stream:
> + Stream
> + A distinct flow of data (image data or metadata) over a media pipeline
> + from source to sink. A source may be e.g. an image sensor and a sink
> + e.g. a memory buffer.
Hmm, I think this is a bit confusing. I think it would be better to replace
"from source to sink" with "from the initial source to the final sink".
The original text doesn't make it clear that there can be many hops in between.
So also: "A source" -> "An initial source", and "a sink" -> "a final sink".
Note that "media pipeline" isn't defined either. Should that be added?
Finally, I think this should be a separate patch as it has nothing to do with
adding the INTERNAL pad flag.
> +
> V4L2 API
> **V4L2 userspace API**
>
> diff --git a/Documentation/userspace-api/media/mediactl/media-types.rst b/Documentation/userspace-api/media/mediactl/media-types.rst
> index 0ffeece1e0c8..28941da27790 100644
> --- a/Documentation/userspace-api/media/mediactl/media-types.rst
> +++ b/Documentation/userspace-api/media/mediactl/media-types.rst
> @@ -361,6 +361,7 @@ Types and flags used to represent the media graph elements
> .. _MEDIA-PAD-FL-SINK:
> .. _MEDIA-PAD-FL-SOURCE:
> .. _MEDIA-PAD-FL-MUST-CONNECT:
> +.. _MEDIA-PAD-FL-INTERNAL:
>
> .. flat-table:: Media pad flags
> :header-rows: 0
> @@ -382,6 +383,11 @@ Types and flags used to represent the media graph elements
> when this flag isn't set; the absence of the flag doesn't imply
> there is none.
>
> + * - ``MEDIA_PAD_FL_INTERNAL``
> + - The internal flag indicates an internal pad that has no external
> + connections. Such a pad shall not be connected with a link. The
> + internal flag indicates that the :ref:``stream
> + <media-glossary-stream>`` either starts or ends in the entity.
This suggests that INTERNAL can be used for both sinks and sources, but...
>
> One and only one of ``MEDIA_PAD_FL_SINK`` and ``MEDIA_PAD_FL_SOURCE``
> must be set for every pad.
> diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c
> index 543a392f8635..f5f290781021 100644
> --- a/drivers/media/mc/mc-entity.c
> +++ b/drivers/media/mc/mc-entity.c
> @@ -213,7 +213,9 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
> iter->index = i++;
>
> if (hweight32(iter->flags & (MEDIA_PAD_FL_SINK |
> - MEDIA_PAD_FL_SOURCE)) != 1) {
> + MEDIA_PAD_FL_SOURCE)) != 1 ||
> + (iter->flags & MEDIA_PAD_FL_INTERNAL &&
> + !(iter->flags & MEDIA_PAD_FL_SINK))) {
...this appears to limit it to just sinks.
Regards,
Hans
> ret = -EINVAL;
> break;
> }
> @@ -1075,7 +1077,8 @@ int media_get_pad_index(struct media_entity *entity, u32 pad_type,
>
> for (i = 0; i < entity->num_pads; i++) {
> if ((entity->pads[i].flags &
> - (MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_SOURCE)) != pad_type)
> + (MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_SOURCE |
> + MEDIA_PAD_FL_INTERNAL)) != pad_type)
> continue;
>
> if (entity->pads[i].sig_type == sig_type)
> @@ -1100,6 +1103,9 @@ media_create_pad_link(struct media_entity *source, u16 source_pad,
> return -EINVAL;
> if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
> return -EINVAL;
> + if (WARN_ON(source->pads[source_pad].flags & MEDIA_PAD_FL_INTERNAL) ||
> + WARN_ON(source->pads[sink_pad].flags & MEDIA_PAD_FL_INTERNAL))
> + return -EINVAL;
>
> link = media_add_link(&source->links);
> if (link == NULL)
> diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
> index 1c80b1d6bbaf..80cfd12a43fc 100644
> --- a/include/uapi/linux/media.h
> +++ b/include/uapi/linux/media.h
> @@ -208,6 +208,7 @@ struct media_entity_desc {
> #define MEDIA_PAD_FL_SINK (1U << 0)
> #define MEDIA_PAD_FL_SOURCE (1U << 1)
> #define MEDIA_PAD_FL_MUST_CONNECT (1U << 2)
> +#define MEDIA_PAD_FL_INTERNAL (1U << 3)
>
> struct media_pad_desc {
> __u32 entity; /* entity ID */
