[PATCH 0/2] rcar-csi2: Serialize format cfg and improve mutex handling

[PATCH 0/2] rcar-csi2: Serialize format cfg and improve mutex handling

[Niklas Söderlund]

Hello Hans,

This series improves the mutex handling of the R-Car CSI-2 driver. While 
working with other drivers it have surfaced that drivers are responsible 
to serialize format configuration.

Patch 1/2 adds a bit of housekeeping to the mutex used in the driver 
while patch 2/2 adds the format serialization.

The series is based on the latest media-tree and tested on M3-N and H3 
ES2.0 without any regressions found.

Niklas Söderlund (2):
  media: rcar-csi2: Cleanup mutex on remove and fail
  media: rcar-csi2: Serialize access to set_fmt and get_fmt

 drivers/media/platform/rcar-vin/rcar-csi2.c | 25 +++++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

-- 
2.32.0

[PATCH 1/2] media: rcar-csi2: Cleanup mutex on remove and fail

[Niklas Söderlund]

The mutex was not destroyed on remove or failed probe, fix this.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 drivers/media/platform/rcar-vin/rcar-csi2.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
index e28eff0396888f2d..a02573dbd5da4f62 100644
--- a/drivers/media/platform/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
@@ -1245,14 +1245,14 @@ static int rcsi2_probe(struct platform_device *pdev)
 	ret = rcsi2_probe_resources(priv, pdev);
 	if (ret) {
 		dev_err(priv->dev, "Failed to get resources\n");
-		return ret;
+		goto error_mutex;
 	}
 
 	platform_set_drvdata(pdev, priv);
 
 	ret = rcsi2_parse_dt(priv);
 	if (ret)
-		return ret;
+		goto error_mutex;
 
 	priv->subdev.owner = THIS_MODULE;
 	priv->subdev.dev = &pdev->dev;
@@ -1272,21 +1272,23 @@ static int rcsi2_probe(struct platform_device *pdev)
 	ret = media_entity_pads_init(&priv->subdev.entity, NR_OF_RCAR_CSI2_PAD,
 				     priv->pads);
 	if (ret)
-		goto error;
+		goto error_async;
 
 	pm_runtime_enable(&pdev->dev);
 
 	ret = v4l2_async_register_subdev(&priv->subdev);
 	if (ret < 0)
-		goto error;
+		goto error_async;
 
 	dev_info(priv->dev, "%d lanes found\n", priv->lanes);
 
 	return 0;
 
-error:
+error_async:
 	v4l2_async_notifier_unregister(&priv->notifier);
 	v4l2_async_notifier_cleanup(&priv->notifier);
+error_mutex:
+	mutex_destroy(&priv->lock);
 
 	return ret;
 }
@@ -1301,6 +1303,8 @@ static int rcsi2_remove(struct platform_device *pdev)
 
 	pm_runtime_disable(&pdev->dev);
 
+	mutex_destroy(&priv->lock);
+
 	return 0;
 }
 
-- 
2.32.0

[PATCH 2/2] media: rcar-csi2: Serialize access to set_fmt and get_fmt

[Niklas Söderlund]

The access to the internal storage of the format rcar_csi2.mf should be
serialized, extend the exciting lock mutex to also cover this.

While at it document the mutex.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 drivers/media/platform/rcar-vin/rcar-csi2.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
index a02573dbd5da4f62..2fdfdc38de424c72 100644
--- a/drivers/media/platform/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
@@ -370,9 +370,8 @@ struct rcar_csi2 {
 	struct v4l2_subdev *remote;
 	unsigned int remote_pad;
 
+	struct mutex lock; /* Protects mf and stream_count. */
 	struct v4l2_mbus_framefmt mf;
-
-	struct mutex lock;
 	int stream_count;
 
 	unsigned short lanes;
@@ -725,6 +724,8 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
 	struct rcar_csi2 *priv = sd_to_csi2(sd);
 	struct v4l2_mbus_framefmt *framefmt;
 
+	mutex_lock(&priv->lock);
+
 	if (!rcsi2_code_to_fmt(format->format.code))
 		format->format.code = rcar_csi2_formats[0].code;
 
@@ -735,6 +736,8 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
 		*framefmt = format->format;
 	}
 
+	mutex_unlock(&priv->lock);
+
 	return 0;
 }
 
@@ -744,11 +747,15 @@ static int rcsi2_get_pad_format(struct v4l2_subdev *sd,
 {
 	struct rcar_csi2 *priv = sd_to_csi2(sd);
 
+	mutex_lock(&priv->lock);
+
 	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
 		format->format = priv->mf;
 	else
 		format->format = *v4l2_subdev_get_try_format(sd, sd_state, 0);
 
+	mutex_unlock(&priv->lock);
+
 	return 0;
 }
 
-- 
2.32.0

Re: [PATCH 1/2] media: rcar-csi2: Cleanup mutex on remove and fail

[Jacopo Mondi]

Hi Niklas,

On Sun, Aug 15, 2021 at 04:49:14AM +0200, Niklas Söderlund wrote:
> The mutex was not destroyed on remove or failed probe, fix this.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Looks good!

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
   j

> ---
>  drivers/media/platform/rcar-vin/rcar-csi2.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index e28eff0396888f2d..a02573dbd5da4f62 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -1245,14 +1245,14 @@ static int rcsi2_probe(struct platform_device *pdev)
>  	ret = rcsi2_probe_resources(priv, pdev);
>  	if (ret) {
>  		dev_err(priv->dev, "Failed to get resources\n");
> -		return ret;
> +		goto error_mutex;
>  	}
>
>  	platform_set_drvdata(pdev, priv);
>
>  	ret = rcsi2_parse_dt(priv);
>  	if (ret)
> -		return ret;
> +		goto error_mutex;
>
>  	priv->subdev.owner = THIS_MODULE;
>  	priv->subdev.dev = &pdev->dev;
> @@ -1272,21 +1272,23 @@ static int rcsi2_probe(struct platform_device *pdev)
>  	ret = media_entity_pads_init(&priv->subdev.entity, NR_OF_RCAR_CSI2_PAD,
>  				     priv->pads);
>  	if (ret)
> -		goto error;
> +		goto error_async;
>
>  	pm_runtime_enable(&pdev->dev);
>
>  	ret = v4l2_async_register_subdev(&priv->subdev);
>  	if (ret < 0)
> -		goto error;
> +		goto error_async;
>
>  	dev_info(priv->dev, "%d lanes found\n", priv->lanes);
>
>  	return 0;
>
> -error:
> +error_async:
>  	v4l2_async_notifier_unregister(&priv->notifier);
>  	v4l2_async_notifier_cleanup(&priv->notifier);
> +error_mutex:
> +	mutex_destroy(&priv->lock);
>
>  	return ret;
>  }
> @@ -1301,6 +1303,8 @@ static int rcsi2_remove(struct platform_device *pdev)
>
>  	pm_runtime_disable(&pdev->dev);
>
> +	mutex_destroy(&priv->lock);
> +
>  	return 0;
>  }
>
> --
> 2.32.0
>

Re: [PATCH 2/2] media: rcar-csi2: Serialize access to set_fmt and get_fmt

[Jacopo Mondi]

Hi Niklas,

On Sun, Aug 15, 2021 at 04:49:15AM +0200, Niklas Söderlund wrote:
> The access to the internal storage of the format rcar_csi2.mf should be
> serialized, extend the exciting lock mutex to also cover this.

truly an exciting lock mutex indeed! :D

>
> While at it document the mutex.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
   j

> ---
>  drivers/media/platform/rcar-vin/rcar-csi2.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index a02573dbd5da4f62..2fdfdc38de424c72 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -370,9 +370,8 @@ struct rcar_csi2 {
>  	struct v4l2_subdev *remote;
>  	unsigned int remote_pad;
>
> +	struct mutex lock; /* Protects mf and stream_count. */
>  	struct v4l2_mbus_framefmt mf;
> -
> -	struct mutex lock;
>  	int stream_count;
>
>  	unsigned short lanes;
> @@ -725,6 +724,8 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
>  	struct rcar_csi2 *priv = sd_to_csi2(sd);
>  	struct v4l2_mbus_framefmt *framefmt;
>
> +	mutex_lock(&priv->lock);
> +
>  	if (!rcsi2_code_to_fmt(format->format.code))
>  		format->format.code = rcar_csi2_formats[0].code;
>
> @@ -735,6 +736,8 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
>  		*framefmt = format->format;
>  	}
>
> +	mutex_unlock(&priv->lock);
> +
>  	return 0;
>  }
>
> @@ -744,11 +747,15 @@ static int rcsi2_get_pad_format(struct v4l2_subdev *sd,
>  {
>  	struct rcar_csi2 *priv = sd_to_csi2(sd);
>
> +	mutex_lock(&priv->lock);
> +
>  	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
>  		format->format = priv->mf;
>  	else
>  		format->format = *v4l2_subdev_get_try_format(sd, sd_state, 0);
>
> +	mutex_unlock(&priv->lock);
> +
>  	return 0;
>  }
>
> --
> 2.32.0
>