Re: [PATCH v3 03/10] media: mc: Add INTERNAL pad flag

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Jacopo,

Thanks for the review.

On Thu, Aug 10, 2023 at 04:12:18PM +0200, Jacopo Mondi wrote:
> Hi Sakari
> 
> On Tue, Aug 08, 2023 at 10:55:31AM +0300, 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.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  Documentation/userspace-api/media/glossary.rst             | 6 ++++++
> >  Documentation/userspace-api/media/mediactl/media-types.rst | 6 ++++++
> >  drivers/media/mc/mc-entity.c                               | 6 +++++-
> >  include/uapi/linux/media.h                                 | 1 +
> >  4 files changed, 18 insertions(+), 1 deletion(-)
> >
> > 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.
> > +
> >      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.
> >
> >  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 4991281dcccc..03a9e0b8ebab 100644
> > --- a/drivers/media/mc/mc-entity.c
> > +++ b/drivers/media/mc/mc-entity.c
> > @@ -1071,7 +1071,8 @@ 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)
> > @@ -1094,6 +1095,9 @@ media_create_pad_link(struct media_entity *source, u16 source_pad,
> >  		return -EINVAL;
> >  	if (WARN_ON(!(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE)))
> >  		return -EINVAL;
> > +	if (WARN_ON(source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE &&
> 
> Why do you need to check for this again here ? Hasn't the previous
> if() clause just validated that
> 
>         source->pads[source_pad].flags & MEDIA_PAD_FL_SOURCE ?

Yes, this needs to be changed. As a link is created here, the internal flag
shouldn't be present in neither sink nor source pads. I may have forgotten
to address this previously, I'll do this for v4.

> 
> > +		    source->pads[source_pad].flags & MEDIA_PAD_FL_INTERNAL))
> > +		return -EINVAL;
> >  	if (WARN_ON(!(sink->pads[sink_pad].flags & MEDIA_PAD_FL_SINK)))
> >  		return -EINVAL;
> >
> > 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