[PATCH v7 07/11] media: rcar-csi2: Add .get_frame_desc op

[Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>]

Add v4l2_subdev_pad_ops.get_frame_desc() implementation.

We also implement a fallback for the case where the upstream subdevice
does not implement .get_frame_desc. It assumes a single stream with VC =
0 and DT based on the configured stream mbus format.

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
---
 drivers/media/platform/renesas/rcar-csi2.c | 77 ++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index c064979003ed..7bff2fe8daad 100644
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -1935,12 +1935,89 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
 	return 0;
 }
 
+static int rcsi2_get_frame_desc_fallback(struct v4l2_subdev *sd,
+					 unsigned int pad,
+					 struct v4l2_mbus_frame_desc *fd)
+{
+	struct v4l2_subdev_route *route;
+	const struct rcar_csi2_format *format;
+	struct v4l2_subdev_state *state;
+	struct v4l2_mbus_framefmt *fmt;
+	int ret = 0;
+
+	state = v4l2_subdev_lock_and_get_active_state(sd);
+
+	if (state->routing.num_routes != 1) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	route = &state->routing.routes[0];
+
+	if (route->source_pad != pad) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	fmt = v4l2_subdev_state_get_format(state, route->sink_pad,
+					   route->sink_stream);
+	if (!fmt) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	format = rcsi2_code_to_fmt(fmt->code);
+	if (!format) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	fd->num_entries = 1;
+	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
+	fd->entry[0].stream = route->source_stream;
+	fd->entry[0].pixelcode = fmt->code;
+	fd->entry[0].bus.csi2.vc = 0;
+	fd->entry[0].bus.csi2.dt = format->datatype;
+
+out:
+	v4l2_subdev_unlock_state(state);
+
+	return ret;
+}
+
+static int rcsi2_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+				struct v4l2_mbus_frame_desc *fd)
+{
+	struct rcar_csi2 *priv = sd_to_csi2(sd);
+	int ret;
+
+	/*
+	 * Providing a frame descriptor on the source pad only makes sense on
+	 * Gen4. On Gen3 the CSI-2 IP is used to demux the CSI streams to each
+	 * VIN instance, while on Gen4 this job is done by the Channel Selector
+	 * of the ISP, and that needs the frame descriptors. So WARN if someone
+	 * calls this on Gen3, as it indicates a driver bug.
+	 */
+	if (WARN_ON(!priv->info->use_isp))
+		return -ENOTTY;
+
+	if (WARN_ON(pad != RCAR_CSI2_SOURCE_VC0))
+		return -EINVAL;
+
+	ret = v4l2_subdev_get_frame_desc_passthrough(sd, pad, fd);
+	if (ret == -ENOIOCTLCMD)
+		ret = rcsi2_get_frame_desc_fallback(sd, pad, fd);
+	return ret;
+}
+
 static const struct v4l2_subdev_pad_ops rcar_csi2_pad_ops = {
 	.enable_streams = rcsi2_enable_streams,
 	.disable_streams = rcsi2_disable_streams,
 
 	.set_fmt = rcsi2_set_pad_format,
 	.get_fmt = v4l2_subdev_get_fmt,
+
+	.get_frame_desc = rcsi2_get_frame_desc,
 };
 
 static const struct v4l2_subdev_ops rcar_csi2_subdev_ops = {

-- 
2.43.0