media: subdev: add "opposite" stream helper funcs

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>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 0429da031baf..7bb7c0db0bb2 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1540,6 +1540,55 @@ 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) {
+			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 */