libcamera: v4l2_subdevice: Add V4L2Subdevice::Route structure

The V4L2Subdevice class deals with streams in two places:

- In routing tables, streams as expressed as a pad number and a stream
  number in a v4l2_subdev_route instance.
- In the format and selection get and set functions, streams as
  expressed using the Stream structure, which binds the pad number and
  stream number.

Expressing streams in different ways requires pipeline handlers and
other helpers to convert between the two representations. This isn't
much of an issue yet as libcamera has little stream-aware code, but it
is expected to increasingly become a burden.

To simplify the API, introduce a V4L2Subdevice::Route structure that
mimicks the kernel v4l2_subdev_route structure but represents streams as
V4L2Subdevice::Stream instances. This will improve seamless integration
of routes, formats and selection rectangles.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

2 files changed, 8 insertions, 14 deletions

diff --git a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
index a3782aea..63082cea 100644
--- a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
+++ b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
@@ -827,16 +827,10 @@ int PipelineHandlerISI::configure(Camera *camera, CameraConfiguration *c)
 	unsigned int xbarFirstSource = crossbar_->entity()->pads().size() / 2 + 1;
 
 	for (const auto &[idx, config] : utils::enumerate(*c)) {
-		struct v4l2_subdev_route route = {
-			.sink_pad = data->xbarSink_,
-			.sink_stream = 0,
-			.source_pad = static_cast<uint32_t>(xbarFirstSource + idx),
-			.source_stream = 0,
-			.flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE,
-			.reserved = {}
-		};
-
-		routing.push_back(route);
+		uint32_t sourcePad = xbarFirstSource + idx;
+		routing.emplace_back(V4L2Subdevice::Stream{ data->xbarSink_, 0 },
+				     V4L2Subdevice::Stream{ sourcePad, 0 },
+				     V4L2_SUBDEV_ROUTE_FL_ACTIVE);
 	}
 
 	int ret = crossbar_->setRouting(&routing, V4L2Subdevice::ActiveFormat);
diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index feea26fd..01f2a977 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -852,17 +852,17 @@ std::vector<const MediaPad *> SimpleCameraData::routedSourcePads(MediaPad *sink)
 
 	std::vector<const MediaPad *> pads;
 
-	for (const struct v4l2_subdev_route &route : routing) {
-		if (sink->index() != route.sink_pad ||
+	for (const V4L2Subdevice::Route &route : routing) {
+		if (sink->index() != route.sink.pad ||
 		    !(route.flags & V4L2_SUBDEV_ROUTE_FL_ACTIVE))
 			continue;
 
-		const MediaPad *pad = entity->getPadByIndex(route.source_pad);
+		const MediaPad *pad = entity->getPadByIndex(route.source.pad);
 		if (!pad) {
 			LOG(SimplePipeline, Warning)
 				<< "Entity " << entity->name()
 				<< " has invalid route source pad "
-				<< route.source_pad;
+				<< route.source.pad;
 		}
 
 		pads.push_back(pad);