Hi Laurent,
On Wed, Mar 20, 2024 at 12:17:07AM +0200, Laurent Pinchart wrote:
> On Thu, Mar 14, 2024 at 09:17:08AM +0200, Tomi Valkeinen wrote:
> > On 13/03/2024 09:24, 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.
> > > Internal source pads are pads that have both SINK and INTERNAL flags set.
> > >
> > > 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>
> > > ---
> > > .../userspace-api/media/mediactl/media-types.rst | 8 ++++++++
> > > drivers/media/mc/mc-entity.c | 10 ++++++++--
> > > include/uapi/linux/media.h | 1 +
> > > 3 files changed, 17 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Documentation/userspace-api/media/mediactl/media-types.rst b/Documentation/userspace-api/media/mediactl/media-types.rst
> > > index 6332e8395263..f55ef055bcf8 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
> > > @@ -381,6 +382,13 @@ Types and flags used to represent the media graph elements
> > > enabled links even 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.
>
> I would expand this slightly, as it's the only source of documentation
> regarding internal pads.
Patch 9 adds more documentation, this patch is for MC only.
>
> - The internal flag indicates an internal pad that has no external
> connections. This can be used to model, for instance, the pixel array
> internal to an image sensor. As they are internal to entities,
> internal pads shall not be connected with links.
I'd drop the sentence related to sensors.
>
> > > +
> > > + The internal flag may currently be present only in a source pad where
> >
> > s/source/sink/
> >
> > Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> > > + it indicates that the :ref:``stream <media-glossary-stream>``
> > > + originates from within the entity.
> > >
> > > 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 0e28b9a7936e..1973e9e1013e 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))) {
> > > ret = -EINVAL;
> > > break;
> > > }
>
> This may become more readable written as a switch statement:
>
> const u32 pad_flags_mask = MEDIA_PAD_FL_SINK |
> MEDIA_PAD_FL_SOURCE |
> MEDIA_PAD_FL_INTERNAL;
>
> switch (iter->flags & pad_flags_mask) {
> case MEDIA_PAD_FL_SINK:
> case MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_INTERNAL:
> case MEDIA_PAD_FL_SOURCE:
> break;
>
> default:
> ret = -EINVAL;
> break;
> }
>
> if (ret)
> break;
>
> And now that I've written this, I'm not too sure anymore :-) Another
> option would be
>
>
> const u32 pad_flags = iter->flags & (MEDIA_PAD_FL_SINK |
> MEDIA_PAD_FL_SOURCE |
> MEDIA_PAD_FL_INTERNAL);
>
> if (pad_flags != MEDIA_PAD_FL_SINK &&
> pad_flags != MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_INTERNAL
> pad_flags != MEDIA_PAD_FL_SOURCE) {
> ret = -EINVAL;
> break;
> }
>
> Up to you.
I'd prefer to keep it as-is since the original check is testing two
independent things instead of merging them: that only either SINK or SOURCE
is set, and then separately that if INTERNAL is set, then SINK is set, too.
Of the two options you suggested, I prefer the latter.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Thank you!
>
> > > @@ -1112,7 +1114,8 @@ 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)
> > > @@ -1142,6 +1145,9 @@ 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(sink->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 */
>
--
Regards,
Sakari Ailus
