Re: [PATCH/RFC v2 05/15] rcar-csi2: count usage for each source pad

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On Thu, Dec 14, 2017 at 08:08:25PM +0100, Niklas Söderlund wrote:
> The R-Car CSI-2 hardware can output the same virtual channel
> simultaneously to more then one R-Car VIN. For this reason we need to
> move the usage counting from the global device to each source pad.
> 
> If a source pads usage count go from 0 to 1 we need to signal that a new
> stream should start, likewise if it go from 1 to 0 we need to stop a
> stream. At the same time we only want to start or stop the R-Car
> CSI-2 device only on the first or last stream.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> ---
>  drivers/media/platform/rcar-vin/rcar-csi2.c | 38 +++++++++++++++++++++++------
>  1 file changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index 8ce0bfeef1113f9c..e0f56cc3d25179a9 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -328,6 +328,14 @@ enum rcar_csi2_pads {
>  	NR_OF_RCAR_CSI2_PAD,
>  };
>  
> +static int rcar_csi2_pad_to_vc(unsigned int pad)
> +{
> +	if (pad < RCAR_CSI2_SOURCE_VC0 || pad > RCAR_CSI2_SOURCE_VC3)
> +		return -EINVAL;
> +
> +	return pad - RCAR_CSI2_SOURCE_VC0;
> +}
> +
>  struct rcar_csi2_info {
>  	const struct phypll_hsfreqrange *hsfreqrange;
>  	const struct phtw_testdin_data *testdin_data;
> @@ -350,7 +358,7 @@ struct rcar_csi2 {
>  	struct v4l2_mbus_framefmt mf;
>  
>  	struct mutex lock;
> -	int stream_count;
> +	int stream_count[4];

Why 4?

>  
>  	unsigned short lanes;
>  	unsigned char lane_swap[4];
> @@ -630,7 +638,13 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, unsigned int pad,
>  {
>  	struct rcar_csi2 *priv = sd_to_csi2(sd);
>  	struct v4l2_subdev *nextsd;
> -	int ret;
> +	unsigned int i, count = 0;
> +	int ret, vc;
> +
> +	/* Only allow stream control on source pads and valid vc */
> +	vc = rcar_csi2_pad_to_vc(pad);
> +	if (vc < 0)
> +		return vc;
>  
>  	/* Only one stream on each source pad */
>  	if (stream != 0)
> @@ -642,7 +656,10 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, unsigned int pad,
>  	if (ret)
>  		goto out;
>  
> -	if (enable && priv->stream_count == 0) {
> +	for (i = 0; i < 4; i++)
> +		count += priv->stream_count[i];
> +
> +	if (enable && count == 0) {
>  		pm_runtime_get_sync(priv->dev);
>  
>  		ret = rcar_csi2_start(priv);
> @@ -650,20 +667,23 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, unsigned int pad,
>  			pm_runtime_put(priv->dev);
>  			goto out;
>  		}
> +	} else if (!enable && count == 1) {
> +		rcar_csi2_stop(priv);
> +		pm_runtime_put(priv->dev);
> +	}
>  
> +	if (enable && priv->stream_count[vc] == 0) {
>  		ret = v4l2_subdev_call(nextsd, video, s_stream, 1);
>  		if (ret) {
>  			rcar_csi2_stop(priv);
>  			pm_runtime_put(priv->dev);
>  			goto out;
>  		}
> -	} else if (!enable && priv->stream_count == 1) {
> -		rcar_csi2_stop(priv);
> +	} else if (!enable && priv->stream_count[vc] == 1) {

Do I understand correctly that you can start and streams here one by one,
independently of each other?

Sometimes this might not be the case. I wonder if we should have a way to
tell that to the caller.

>  		ret = v4l2_subdev_call(nextsd, video, s_stream, 0);
> -		pm_runtime_put(priv->dev);
>  	}
>  
> -	priv->stream_count += enable ? 1 : -1;
> +	priv->stream_count[vc] += enable ? 1 : -1;
>  out:
>  	mutex_unlock(&priv->lock);
>  
> @@ -919,7 +939,9 @@ static int rcar_csi2_probe(struct platform_device *pdev)
>  	priv->dev = &pdev->dev;
>  
>  	mutex_init(&priv->lock);
> -	priv->stream_count = 0;
> +
> +	for (i = 0; i < 4; i++)
> +		priv->stream_count[i] = 0;
>  
>  	ret = rcar_csi2_probe_resources(priv, pdev);
>  	if (ret) {
> -- 
> 2.15.1
> 

-- 
Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx



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