Em Thu, 13 Dec 2018 14:41:13 -0200
Mauro Carvalho Chehab <mchehab+sams...@kernel.org> escreveu:
> Em Thu, 13 Dec 2018 14:41:10 +0100
> hverkuil-ci...@xs4all.nl escreveu:
>
> > From: Hans Verkuil <hans.verk...@cisco.com>
> >
> > Extend the topology struct with a properties array.
> >
> > Add a new media_v2_prop structure to store property information.
> >
> > Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
> > ---
> > include/uapi/linux/media.h | 56 ++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 56 insertions(+)
> >
> > diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
> > index e5d0c5c611b5..12982327381e 100644
> > --- a/include/uapi/linux/media.h
> > +++ b/include/uapi/linux/media.h
> > @@ -342,6 +342,58 @@ struct media_v2_link {
> > __u32 reserved[6];
> > } __attribute__ ((packed));
> >
> > +#define MEDIA_PROP_TYPE_GROUP 1
> > +#define MEDIA_PROP_TYPE_U64 2
> > +#define MEDIA_PROP_TYPE_S64 3
> > +#define MEDIA_PROP_TYPE_STRING 4
>
> > +#define MEDIA_OWNER_TYPE_ENTITY 0
> > +#define MEDIA_OWNER_TYPE_PAD 1
> > +#define MEDIA_OWNER_TYPE_LINK 2
> > +#define MEDIA_OWNER_TYPE_INTF 3
> > +#define MEDIA_OWNER_TYPE_PROP 4
>
> > +
> > +/**
> > + * struct media_v2_prop - A media property
> > + *
> > + * @id: The unique non-zero ID of this property
> > + * @type: Property type
>
> > + * @owner_id: The ID of the object this property belongs to
>
> I'm in doubt about this. With this field, properties and objects
> will have a 1:1 mapping. If this is removed, it would be possible
> to map 'n' objects to a single property (N:1 mapping), with could
> be interesting.
Just to be clear: if we don't add it here, we would need to add a
properties ID for every object type (zero meaning that no properties
were associated to it).
>
> > + * @owner_type: The type of the object this property belongs to
>
> I would remove this (and the corresponding defines). The type
> can easily be identified from the owner_id - as it already contains
> the object type embedded at the ID.
> In other words, it is:
>
> owner_type = (owner_id & MEDIA_ENT_TYPE_MASK) >> MEDIA_ENT_TYPE_SHIFT;
>
> > + * @flags: Property flags
> > + * @name: Property name
> > + * @payload_size: Property payload size, 0 for U64/S64
> > + * @payload_offset: Property payload starts at this offset from &prop.id.
> > + * This is 0 for U64/S64.
>
> Please specify how this will be used for the group type, with is not
> obvious. I *suspect* that, on a group, you'll be adding a vector of
> u32 (cpu endian) and payload_size is the number of elements at the
> vector (or the vector size?).
>
> > + * @reserved: Property reserved field, will be zeroed.
> > + */
> > +struct media_v2_prop {
> > + __u32 id;
> > + __u32 type;
> > + __u32 owner_id;
> > + __u32 owner_type;
> > + __u32 flags;
>
> The way it is defined, name won't be 64-bits aligned (well, it will, if
> you remove the owner_type).
>
> > + char name[32];
> > + __u32 payload_size;
> > + __u32 payload_offset;
> > + __u32 reserved[18];
> > +} __attribute__ ((packed));
> > +
> > +static inline const char *media_prop2string(const struct media_v2_prop
> > *prop)
> > +{
> > + return (const char *)prop + prop->payload_offset;
> > +}
> > +
> > +static inline __u64 media_prop2u64(const struct media_v2_prop *prop)
> > +{
> > + return *(const __u64 *)((const char *)prop + prop->payload_offset);
> > +}
> > +
> > +static inline __s64 media_prop2s64(const struct media_v2_prop *prop)
> > +{
> > + return *(const __s64 *)((const char *)prop + prop->payload_offset);
> > +}
> > +
>
> Shouldn't you define also a media_prop2group()?
>
> > struct media_v2_topology {
> > __u64 topology_version;
> >
> > @@ -360,6 +412,10 @@ struct media_v2_topology {
> > __u32 num_links;
> > __u32 reserved4;
> > __u64 ptr_links;
> > +
> > + __u32 num_props;
> > + __u32 props_payload_size;
> > + __u64 ptr_props;
>
> Please document those new fields.
>
> > } __attribute__ ((packed));
> >
> > /* ioctls */
>
>
>
> Thanks,
> Mauro
Thanks,
Mauro
