[PATCH 2/2] media: staging: imx: configure src_mux in csi_start

[Michael Tretter <m.tretter@pengutronix.de>]

After media_pipeline_start() was called, the media graph is assumed to
be validated. It won't be validated again if a second stream starts.

The imx-media-csi driver, however, changes hardware configuration in the
link_validate() callback. This can result in started streams with
misconfigured hardware.

In the concrete example, the ipu2_csi1_mux is driven by a parallel video
input. After the media pipeline has been started with this
configuration, a second stream is configured to use ipu1_csi0 with
MIPI-CSI input from imx6-mipi-csi2. This may require the reconfiguration
of ipu1_csi0 with ipu_set_csi_src_mux(). Since the media pipeline is
already running, link_validate won't be called, and the ipu1_csi0 won't
be reconfigured. The resulting video is broken, because the
ipu1_csi0_mux is misconfigured, but no error is reported.

Move ipu_set_csi_src_mux from csi_link_validate to csi_start to ensure
that input to ipu1_csi0 is configured correctly when starting the
stream. This is a local reconfiguration in ipu1_csi0 and is possible
while the media pipeline is running.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Fixes: 4a34ec8e470c ("[media] media: imx: Add CSI subdev driver")
Cc: stable@vger.kernel.org
---
 drivers/staging/media/imx/imx-media-csi.c | 44 +++++++++++++++++--------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index 55a7d8f38465..1bc644f73a9d 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -744,6 +744,28 @@ static int csi_setup(struct csi_priv *priv,
 	return 0;
 }
 
+static void csi_set_src(struct csi_priv *priv,
+			struct v4l2_mbus_config *mbus_cfg)
+{
+	bool is_csi2;
+
+	is_csi2 = !is_parallel_bus(mbus_cfg);
+	if (is_csi2) {
+		/*
+		 * NOTE! It seems the virtual channels from the mipi csi-2
+		 * receiver are used only for routing by the video mux's,
+		 * or for hard-wired routing to the CSI's. Once the stream
+		 * enters the CSI's however, they are treated internally
+		 * in the IPU as virtual channel 0.
+		 */
+		ipu_csi_set_mipi_datatype(priv->csi, 0,
+					  &priv->format_mbus[CSI_SINK_PAD]);
+	}
+
+	/* select either parallel or MIPI-CSI2 as input to CSI */
+	ipu_set_csi_src_mux(priv->ipu, priv->csi_id, is_csi2);
+}
+
 static int csi_start(struct csi_priv *priv)
 {
 	struct v4l2_mbus_config mbus_cfg = { .type = 0 };
@@ -760,6 +782,8 @@ static int csi_start(struct csi_priv *priv)
 	input_fi = &priv->frame_interval[CSI_SINK_PAD];
 	output_fi = &priv->frame_interval[priv->active_output_pad];
 
+	csi_set_src(priv, &mbus_cfg);
+
 	/* start upstream */
 	ret = v4l2_subdev_call(priv->src_sd, video, s_stream, 1);
 	ret = (ret && ret != -ENOIOCTLCMD) ? ret : 0;
@@ -1130,7 +1154,6 @@ static int csi_link_validate(struct v4l2_subdev *sd,
 {
 	struct csi_priv *priv = v4l2_get_subdevdata(sd);
 	struct v4l2_mbus_config mbus_cfg = { .type = 0 };
-	bool is_csi2;
 	int ret;
 
 	ret = v4l2_subdev_link_validate_default(sd, link,
@@ -1145,25 +1168,6 @@ static int csi_link_validate(struct v4l2_subdev *sd,
 		return ret;
 	}
 
-	mutex_lock(&priv->lock);
-
-	is_csi2 = !is_parallel_bus(&mbus_cfg);
-	if (is_csi2) {
-		/*
-		 * NOTE! It seems the virtual channels from the mipi csi-2
-		 * receiver are used only for routing by the video mux's,
-		 * or for hard-wired routing to the CSI's. Once the stream
-		 * enters the CSI's however, they are treated internally
-		 * in the IPU as virtual channel 0.
-		 */
-		ipu_csi_set_mipi_datatype(priv->csi, 0,
-					  &priv->format_mbus[CSI_SINK_PAD]);
-	}
-
-	/* select either parallel or MIPI-CSI2 as input to CSI */
-	ipu_set_csi_src_mux(priv->ipu, priv->csi_id, is_csi2);
-
-	mutex_unlock(&priv->lock);
 	return ret;
 }
 

-- 
2.47.3