Hi Tomi,
On Wed, Apr 21, 2021 at 04:04:22PM +0300, Tomi Valkeinen wrote:
> On 18/04/2021 22:04, Laurent Pinchart wrote:
> > On Thu, Apr 15, 2021 at 04:04:48PM +0300, Tomi Valkeinen wrote:
> >> Add v4l2_subdev_get_format_dir() which can be used to find subdev format
> >> for a specific stream on a multiplexed pad. The function will follow the
> >> routes and links until it finds a non-multiplexed pad.
> >>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> >> ---
> >> drivers/media/v4l2-core/v4l2-subdev.c | 96 +++++++++++++++++++++++++++
> >> include/media/v4l2-subdev.h | 26 ++++++++
> >> 2 files changed, 122 insertions(+)
> >>
> >> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> >> index 7a4f71d8c6c3..430dbdaab080 100644
> >> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> >> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> >> @@ -998,6 +998,102 @@ bool v4l2_subdev_has_route(struct v4l2_subdev_krouting *routing,
> >> }
> >> EXPORT_SYMBOL_GPL(v4l2_subdev_has_route);
> >>
> >> +int v4l2_subdev_get_format_dir(struct media_pad *pad, u16 stream,
> >> + enum v4l2_direction dir,
> >> + struct v4l2_subdev_format *fmt)
> >> +{
> >> + struct device *dev = pad->entity->graph_obj.mdev->dev;
> >> + int ret;
> >> + int i;
> >> +
> >> + dev_dbg(dev, "%s '%s':%u:%u %s\n", __func__,
> >> + pad->entity->name, pad->index, stream,
> >> + dir == V4L2_DIR_SOURCEWARD ? "sourceward" : "sinkward");
> >> +
> >> + while (true) {
> >> + struct v4l2_subdev_krouting routing;
> >> + struct v4l2_subdev_route *route;
> >> +
> >> + if (pad->entity->obj_type != MEDIA_ENTITY_TYPE_V4L2_SUBDEV)
> >> + return -EINVAL;
> >> +
> >> + ret = v4l2_subdev_link_validate_get_format(pad, fmt);
> >> + if (ret == 0)
> >> + return 0;
> >> + else if (ret != -ENOIOCTLCMD)
> >> + return ret;
> >> +
> >> + if (pad->flags &
> >> + (dir == V4L2_DIR_SINKWARD ? MEDIA_PAD_FL_SOURCE :
> >> + MEDIA_PAD_FL_SINK)) {
> >> + pad = media_entity_remote_pad(pad);
> >> +
> >> + if (!pad)
> >> + return -EINVAL;
> >> +
> >> + if (pad->entity->obj_type != MEDIA_ENTITY_TYPE_V4L2_SUBDEV)
> >> + return -EINVAL;
> >> +
> >> + ret = v4l2_subdev_link_validate_get_format(pad, fmt);
> >> + if (ret == 0)
> >> + return 0;
> >> + else if (ret != -ENOIOCTLCMD)
> >> + return ret;
> >> + }
> >> +
> >> + ret = v4l2_subdev_get_krouting(media_entity_to_v4l2_subdev(pad->entity), &routing);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + route = NULL;
> >> + for (i = 0; i < routing.num_routes; ++i) {
> >> + u16 near_pad = dir == V4L2_DIR_SINKWARD ?
> >> + routing.routes[i].sink_pad :
> >> + routing.routes[i].source_pad;
> >> + u16 near_stream = dir == V4L2_DIR_SINKWARD ?
> >> + routing.routes[i].sink_stream :
> >> + routing.routes[i].source_stream;
> >> +
> >> + if (!(routing.routes[i].flags & V4L2_SUBDEV_ROUTE_FL_ACTIVE))
> >> + continue;
> >> +
> >> + if (near_pad != pad->index)
> >> + continue;
> >> +
> >> + if (near_stream != stream)
> >> + continue;
> >> +
> >> + if (route) {
> >> + dev_err(dev,
> >> + "%s: '%s' has multiple active routes for stream %u\n",
> >> + __func__, pad->entity->name, stream);
> >> + v4l2_subdev_free_routing(&routing);
> >> + return -EINVAL;
> >> + }
> >> +
> >> + route = &routing.routes[i];
> >> + }
> >> +
> >> + if (!route) {
> >> + dev_err(dev, "%s: no route found in '%s' for stream %u\n",
> >> + __func__, pad->entity->name, stream);
> >> + v4l2_subdev_free_routing(&routing);
> >> + return -EINVAL;
> >> + }
> >> +
> >> + if (dir == V4L2_DIR_SINKWARD) {
> >> + pad = &pad->entity->pads[route->source_pad];
> >> + stream = route->source_stream;
> >> + } else {
> >> + pad = &pad->entity->pads[route->sink_pad];
> >> + stream = route->sink_stream;
> >> + }
> >> +
> >> + v4l2_subdev_free_routing(&routing);
> >> + }
> >> +}
> >> +EXPORT_SYMBOL_GPL(v4l2_subdev_get_format_dir);
> >> +
> >> int v4l2_subdev_link_validate(struct media_link *link)
> >> {
> >> struct v4l2_subdev *sink;
> >> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> >> index 1843b77dd843..730631f9a091 100644
> >> --- a/include/media/v4l2-subdev.h
> >> +++ b/include/media/v4l2-subdev.h
> >> @@ -1239,4 +1239,30 @@ void v4l2_subdev_cpy_routing(struct v4l2_subdev_krouting *dst,
> >> bool v4l2_subdev_has_route(struct v4l2_subdev_krouting *routing,
> >> unsigned int pad0, unsigned int pad1);
> >>
> >> +/**
> >> + * enum v4l2_direction - Direction either towards the source or the sink
> >> + *
> >> + * @V4L2_DIR_SOURCEWARD: Direction towards the source.
> >> + * @V4L2_DIR_SINKWARD: Direction towards the sink.
> >> + */
> >> +enum v4l2_direction {
> >> + V4L2_DIR_SOURCEWARD,
> >> + V4L2_DIR_SINKWARD,
> >> +};
> >> +
> >> +/**
> >> + * v4l2_subdev_get_format_dir() - Find format by following streams
> >
> > The name is a bit cryptic, and the usage pattern error-prone. Can we do
> > better ? In particular, if we could limit the usage of this function to
> > be called on a non-multiplexed pad, we could drop the stream argument.
> > Deducing the direction argument from the type of pad would also make the
> > API simpler.
>
> Hmm, but that's not what the function does. It follows a specific
> stream, from a multiplexed pad, so it has to get the stream as a parameter.
>
> We can't deduct the direction from the type of the pad. We can of course
> define that given a source pad this function goes sourceward. But if
> that's not what the caller wants, then the caller needs to first follow
> the stream either direction to get a sink pad, and then call this
> function, which doesn't make sense.
What do the current callers need ? We don't have to implement something
that is more generic or featureful than our needs dictate, as this is a
very ad hoc function anyway. If we really need the full behaviour
implemented here, we should at the very least rename the function, but I
think it should be possible to do better overall, perhaps splitting the
operation in the caller into cleaner functions.
> >> + * @pad: The pad from which to start the search
> >> + * @stream: The stream for which we want to find the format
> >> + * @dir: The direction of the search
> >> + * @fmt: Pointer to &struct v4l2_subdev_format where the found format is stored
> >> + *
> >> + * This function attempts to find v4l2_subdev_format for a specific stream on a
> >> + * multiplexed pad by following the stream using routes and links to the specified
> >> + * direction, until a non-multiplexed pad is found.
> >> + */
> >> +int v4l2_subdev_get_format_dir(struct media_pad *pad, u16 stream,
> >> + enum v4l2_direction dir,
> >> + struct v4l2_subdev_format *fmt);
> >> +
> >> #endif
--
Regards,
Laurent Pinchart
