Re: [PATCH v15 12/19] media: subdev: add "opposite" stream helper funcs

[Dafna Hirschfeld <dafna@fastmail.com>]

On 03.10.2022 15:18, Tomi Valkeinen wrote:
>Add two helper functions to make dealing with streams easier:
>
>v4l2_subdev_routing_find_opposite_end - given a routing table and a pad
>+ stream, return the pad + stream on the opposite side of the subdev.
>
>v4l2_subdev_state_get_opposite_stream_format - return a pointer to the
>format on the pad + stream on the opposite side from the given pad +
>stream.
>
>Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
>---
> drivers/media/v4l2-core/v4l2-subdev.c | 49 +++++++++++++++++++++++++++
> include/media/v4l2-subdev.h           | 36 ++++++++++++++++++++
> 2 files changed, 85 insertions(+)
>
>diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>index 1cea6ec750c0..7d2d8e8d3aea 100644
>--- a/drivers/media/v4l2-core/v4l2-subdev.c
>+++ b/drivers/media/v4l2-core/v4l2-subdev.c
>@@ -1514,6 +1514,55 @@ v4l2_subdev_state_get_stream_compose(struct v4l2_subdev_state *state,
> }
> EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_stream_compose);
>
>+int v4l2_subdev_routing_find_opposite_end(const struct v4l2_subdev_krouting *routing,
>+					  u32 pad, u32 stream, u32 *other_pad,
>+					  u32 *other_stream)
>+{
>+	unsigned int i;
>+
>+	for (i = 0; i < routing->num_routes; ++i) {
>+		struct v4l2_subdev_route *route = &routing->routes[i];
>+
>+		if (route->source_pad == pad &&
>+		    route->source_stream == stream) {
>+			if (other_pad)
>+				*other_pad = route->sink_pad;
>+			if (other_stream)
>+				*other_stream = route->sink_stream;
>+			return 0;
>+		}
>+
>+		if (route->sink_pad == pad && route->sink_stream == stream) {

Hi, I think here you should also check that the FL_SOURCE flag is not set to make sure
that sink_pad/stream are used

Thanks,
Dafna

>+			if (other_pad)
>+				*other_pad = route->source_pad;
>+			if (other_stream)
>+				*other_stream = route->source_stream;
>+			return 0;
>+		}
>+	}
>+
>+	return -EINVAL;
>+}
>+EXPORT_SYMBOL_GPL(v4l2_subdev_routing_find_opposite_end);
>+
>+struct v4l2_mbus_framefmt *
>+v4l2_subdev_state_get_opposite_stream_format(struct v4l2_subdev_state *state,
>+					     u32 pad, u32 stream)
>+{
>+	u32 other_pad, other_stream;
>+	int ret;
>+
>+	ret = v4l2_subdev_routing_find_opposite_end(&state->routing,
>+						    pad, stream,
>+						    &other_pad, &other_stream);
>+	if (ret)
>+		return NULL;
>+
>+	return v4l2_subdev_state_get_stream_format(state, other_pad,
>+						   other_stream);
>+}
>+EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_opposite_stream_format);
>+
> #endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
>
> #endif /* CONFIG_MEDIA_CONTROLLER */
>diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
>index d6273ad2eea8..6f4719e28ad1 100644
>--- a/include/media/v4l2-subdev.h
>+++ b/include/media/v4l2-subdev.h
>@@ -1527,6 +1527,42 @@ struct v4l2_rect *
> v4l2_subdev_state_get_stream_compose(struct v4l2_subdev_state *state,
> 				     unsigned int pad, u32 stream);
>
>+/**
>+ * v4l2_subdev_routing_find_opposite_end() - Find the opposite stream
>+ * @routing: routing used to find the opposite side
>+ * @pad: pad id
>+ * @stream: stream id
>+ * @other_pad: pointer used to return the opposite pad
>+ * @other_stream: pointer used to return the opposite stream
>+ *
>+ * This function uses the routing table to find the pad + stream which is
>+ * opposite the given pad + stream.
>+ *
>+ * @other_pad and/or @other_stream can be NULL if the caller does not need the
>+ * value.
>+ *
>+ * Returns 0 on success, or -EINVAL if no matching route is found.
>+ */
>+int v4l2_subdev_routing_find_opposite_end(const struct v4l2_subdev_krouting *routing,
>+					  u32 pad, u32 stream, u32 *other_pad,
>+					  u32 *other_stream);
>+
>+/**
>+ * v4l2_subdev_state_get_opposite_stream_format() - Get pointer to opposite
>+ *                                                  stream format
>+ * @state: subdevice state
>+ * @pad: pad id
>+ * @stream: stream id
>+ *
>+ * This returns a pointer to &struct v4l2_mbus_framefmt for the pad + stream
>+ * that is opposite the given pad + stream in the subdev state.
>+ *
>+ * If the state does not contain the given pad + stream, NULL is returned.
>+ */
>+struct v4l2_mbus_framefmt *
>+v4l2_subdev_state_get_opposite_stream_format(struct v4l2_subdev_state *state,
>+					     u32 pad, u32 stream);
>+
> #endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
>
> #endif /* CONFIG_MEDIA_CONTROLLER */
>-- 
>2.34.1
>