Re: [PATCH v2.1 04/11] media: rcar-csi2: Use the subdev active state

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

Hi Jacopo,

Thanks for this fix, I will test it once I get some time. One comment 
already.

On 2024-05-09 13:06:51 +0200, Jacopo Mondi wrote:
> Create the subdevice state with v4l2_subdev_init_finalize() and
> implement the init_state() operation to guarantee the state is initialized.
> 
> Store the current image format in the subdev active state and remove it
> from the driver private structure.
> 
> To guarantee the same image format is applied to all source pads,
> propagate the format from the sink pad to the sources, disallowing
> changing format on a source pad.
> 
> While at it, define an enum member for the number of pads supported by
> gen4 and store the number of active pads in the driver's private
> structure to handle both gen3 and gen4.
> 
> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> v2->v2.1
> 
> - Fix gen4 issue reported by Niklas: store the number of pads in the
>   driver structure and use it when handling in init_state() and
>   set_pad_format() when applying a format to the source pads
> ---
>  drivers/media/platform/renesas/rcar-csi2.c | 153 ++++++++++++---------
>  1 file changed, 86 insertions(+), 67 deletions(-)
> 
> diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
> index 2d464e43a5be..8482b155522b 100644
> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -579,15 +579,17 @@ enum rcar_csi2_pads {
>  	RCAR_CSI2_SINK,
>  	RCAR_CSI2_SOURCE_VC0,
>  	RCAR_CSI2_SOURCE_VC1,
> +	NR_OF_RCAR_CSI2_ISP_PADS = RCAR_CSI2_SOURCE_VC1,
>  	RCAR_CSI2_SOURCE_VC2,
>  	RCAR_CSI2_SOURCE_VC3,
> -	NR_OF_RCAR_CSI2_PAD,
> +	NR_OF_RCAR_CSI2_VIN_PADS,
>  };

Please don't do this. It's hard to understand the actual values of the 
enum values, and it looks fragile. It's also a hack as the ISP operation 
mode only have the RCAR_CSI2_SINK and RCAR_CSI2_SOURCE_VC0 pads, but 
reading this suggests it also have RCAR_CSI2_SOURCE_VC1.

My preferred solution would be a new helper and not store the number of 
pads in the private data and remove NR_OF_RCAR_CSI2_VIN_PADS. Something 
like,

    static unsigned int rcsi2_num_pads(const struct rcar_csi2 *priv)
    {
	/* Used together with R-Car CSIP, there are one sink and one source pad. */
	if (priv->info->use_isp)
	    return 2;

	/* Used together with R-Car VIN, there are one sink and five source pads. */
	return 5;
    }

> 
>  struct rcar_csi2_info {
>  	int (*init_phtw)(struct rcar_csi2 *priv, unsigned int mbps);
>  	int (*phy_post_init)(struct rcar_csi2 *priv);
> -	int (*start_receiver)(struct rcar_csi2 *priv);
> +	int (*start_receiver)(struct rcar_csi2 *priv,
> +			      struct v4l2_subdev_state *state);
>  	void (*enter_standby)(struct rcar_csi2 *priv);
>  	const struct rcsi2_mbps_reg *hsfreqrange;
>  	unsigned int csi0clkfreqrange;
> @@ -605,7 +607,8 @@ struct rcar_csi2 {
>  	struct reset_control *rstc;
> 
>  	struct v4l2_subdev subdev;
> -	struct media_pad pads[NR_OF_RCAR_CSI2_PAD];
> +	struct media_pad pads[NR_OF_RCAR_CSI2_VIN_PADS];
> +	unsigned int num_pads;
> 
>  	struct v4l2_async_notifier notifier;
>  	struct v4l2_subdev *remote;
> @@ -613,8 +616,6 @@ struct rcar_csi2 {
> 
>  	int channel_vc[4];
> 
> -	struct mutex lock; /* Protects mf and stream_count. */
> -	struct v4l2_mbus_framefmt mf;
>  	int stream_count;
> 
>  	bool cphy;
> @@ -808,20 +809,25 @@ static int rcsi2_get_active_lanes(struct rcar_csi2 *priv,
>  	return 0;
>  }
> 
> -static int rcsi2_start_receiver_gen3(struct rcar_csi2 *priv)
> +static int rcsi2_start_receiver_gen3(struct rcar_csi2 *priv,
> +				     struct v4l2_subdev_state *state)
>  {
>  	const struct rcar_csi2_format *format;
>  	u32 phycnt, vcdt = 0, vcdt2 = 0, fld = 0;
> +	const struct v4l2_mbus_framefmt *fmt;
>  	unsigned int lanes;
>  	unsigned int i;
>  	int mbps, ret;
> 
> +	/* Use the format on the sink pad to compute the receiver config. */
> +	fmt = v4l2_subdev_state_get_format(state, RCAR_CSI2_SINK);
> +
>  	dev_dbg(priv->dev, "Input size (%ux%u%c)\n",
> -		priv->mf.width, priv->mf.height,
> -		priv->mf.field == V4L2_FIELD_NONE ? 'p' : 'i');
> +		fmt->width, fmt->height,
> +		fmt->field == V4L2_FIELD_NONE ? 'p' : 'i');
> 
>  	/* Code is validated in set_fmt. */
> -	format = rcsi2_code_to_fmt(priv->mf.code);
> +	format = rcsi2_code_to_fmt(fmt->code);
>  	if (!format)
>  		return -EINVAL;
> 
> @@ -849,11 +855,11 @@ static int rcsi2_start_receiver_gen3(struct rcar_csi2 *priv)
>  			vcdt2 |= vcdt_part << ((i % 2) * 16);
>  	}
> 
> -	if (priv->mf.field == V4L2_FIELD_ALTERNATE) {
> +	if (fmt->field == V4L2_FIELD_ALTERNATE) {
>  		fld = FLD_DET_SEL(1) | FLD_FLD_EN4 | FLD_FLD_EN3 | FLD_FLD_EN2
>  			| FLD_FLD_EN;
> 
> -		if (priv->mf.height == 240)
> +		if (fmt->height == 240)
>  			fld |= FLD_FLD_NUM(0);
>  		else
>  			fld |= FLD_FLD_NUM(1);
> @@ -1049,15 +1055,18 @@ static int rcsi2_c_phy_setting_v4h(struct rcar_csi2 *priv, int msps)
>  	return 0;
>  }
> 
> -static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv)
> +static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv,
> +				    struct v4l2_subdev_state *state)
>  {
>  	const struct rcar_csi2_format *format;
> +	const struct v4l2_mbus_framefmt *fmt;
>  	unsigned int lanes;
>  	int msps;
>  	int ret;
> 
> -	/* Calculate parameters */
> -	format = rcsi2_code_to_fmt(priv->mf.code);
> +	/* Use the format on the sink pad to compute the receiver config. */
> +	fmt = v4l2_subdev_state_get_format(state, RCAR_CSI2_SINK);
> +	format = rcsi2_code_to_fmt(fmt->code);
>  	if (!format)
>  		return -EINVAL;
> 
> @@ -1114,7 +1123,7 @@ static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv)
>  	return 0;
>  }
> 
> -static int rcsi2_start(struct rcar_csi2 *priv)
> +static int rcsi2_start(struct rcar_csi2 *priv, struct v4l2_subdev_state *state)
>  {
>  	int ret;
> 
> @@ -1122,7 +1131,7 @@ static int rcsi2_start(struct rcar_csi2 *priv)
>  	if (ret < 0)
>  		return ret;
> 
> -	ret = priv->info->start_receiver(priv);
> +	ret = priv->info->start_receiver(priv, state);
>  	if (ret) {
>  		rcsi2_enter_standby(priv);
>  		return ret;
> @@ -1146,17 +1155,16 @@ static void rcsi2_stop(struct rcar_csi2 *priv)
>  static int rcsi2_s_stream(struct v4l2_subdev *sd, int enable)
>  {
>  	struct rcar_csi2 *priv = sd_to_csi2(sd);
> +	struct v4l2_subdev_state *state;
>  	int ret = 0;
> 
> -	mutex_lock(&priv->lock);
> +	if (!priv->remote)
> +		return -ENODEV;
> 
> -	if (!priv->remote) {
> -		ret = -ENODEV;
> -		goto out;
> -	}
> +	state = v4l2_subdev_lock_and_get_active_state(&priv->subdev);
> 
>  	if (enable && priv->stream_count == 0) {
> -		ret = rcsi2_start(priv);
> +		ret = rcsi2_start(priv, state);
>  		if (ret)
>  			goto out;
>  	} else if (!enable && priv->stream_count == 1) {
> @@ -1165,49 +1173,28 @@ static int rcsi2_s_stream(struct v4l2_subdev *sd, int enable)
> 
>  	priv->stream_count += enable ? 1 : -1;
>  out:
> -	mutex_unlock(&priv->lock);
> +	v4l2_subdev_unlock_state(state);
> 
>  	return ret;
>  }
> 
>  static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
> -				struct v4l2_subdev_state *sd_state,
> +				struct v4l2_subdev_state *state,
>  				struct v4l2_subdev_format *format)
>  {
>  	struct rcar_csi2 *priv = sd_to_csi2(sd);
> -	struct v4l2_mbus_framefmt *framefmt;
> 
> -	mutex_lock(&priv->lock);
> +	if (format->pad > RCAR_CSI2_SINK)
> +		return v4l2_subdev_get_fmt(sd, state, format);
> 
>  	if (!rcsi2_code_to_fmt(format->format.code))
>  		format->format.code = rcar_csi2_formats[0].code;
> 
> -	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> -		priv->mf = format->format;
> -	} else {
> -		framefmt = v4l2_subdev_state_get_format(sd_state, 0);
> -		*framefmt = format->format;
> -	}
> -
> -	mutex_unlock(&priv->lock);
> -
> -	return 0;
> -}
> -
> -static int rcsi2_get_pad_format(struct v4l2_subdev *sd,
> -				struct v4l2_subdev_state *sd_state,
> -				struct v4l2_subdev_format *format)
> -{
> -	struct rcar_csi2 *priv = sd_to_csi2(sd);
> -
> -	mutex_lock(&priv->lock);
> +	*v4l2_subdev_state_get_format(state, format->pad) = format->format;
> 
> -	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> -		format->format = priv->mf;
> -	else
> -		format->format = *v4l2_subdev_state_get_format(sd_state, 0);
> -
> -	mutex_unlock(&priv->lock);
> +	/* Propagate the format to the source pads. */
> +	for (unsigned int i = RCAR_CSI2_SOURCE_VC0; i < priv->num_pads; i++)
> +		*v4l2_subdev_state_get_format(state, i) = format->format;
> 
>  	return 0;
>  }
> @@ -1218,7 +1205,7 @@ static const struct v4l2_subdev_video_ops rcar_csi2_video_ops = {
> 
>  static const struct v4l2_subdev_pad_ops rcar_csi2_pad_ops = {
>  	.set_fmt = rcsi2_set_pad_format,
> -	.get_fmt = rcsi2_get_pad_format,
> +	.get_fmt = v4l2_subdev_get_fmt,
>  };
> 
>  static const struct v4l2_subdev_ops rcar_csi2_subdev_ops = {
> @@ -1226,6 +1213,32 @@ static const struct v4l2_subdev_ops rcar_csi2_subdev_ops = {
>  	.pad	= &rcar_csi2_pad_ops,
>  };
> 
> +static int rcsi2_init_state(struct v4l2_subdev *sd,
> +			    struct v4l2_subdev_state *state)
> +{
> +	struct rcar_csi2 *priv = sd_to_csi2(sd);
> +
> +	static const struct v4l2_mbus_framefmt rcar_csi2_default_fmt = {
> +		.width		= 1920,
> +		.height		= 1080,
> +		.code		= MEDIA_BUS_FMT_RGB888_1X24,
> +		.colorspace	= V4L2_COLORSPACE_SRGB,
> +		.field		= V4L2_FIELD_NONE,
> +		.ycbcr_enc	= V4L2_YCBCR_ENC_DEFAULT,
> +		.quantization	= V4L2_QUANTIZATION_DEFAULT,
> +		.xfer_func	= V4L2_XFER_FUNC_DEFAULT,
> +	};
> +
> +	for (unsigned int i = RCAR_CSI2_SINK; i < priv->num_pads; i++)
> +		*v4l2_subdev_state_get_format(state, i) = rcar_csi2_default_fmt;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops rcar_csi2_internal_ops = {
> +	.init_state = rcsi2_init_state,
> +};
> +
>  static irqreturn_t rcsi2_irq(int irq, void *data)
>  {
>  	struct rcar_csi2 *priv = data;
> @@ -1251,14 +1264,17 @@ static irqreturn_t rcsi2_irq(int irq, void *data)
> 
>  static irqreturn_t rcsi2_irq_thread(int irq, void *data)
>  {
> +	struct v4l2_subdev_state *state;
>  	struct rcar_csi2 *priv = data;
> 
> -	mutex_lock(&priv->lock);
> +	state = v4l2_subdev_lock_and_get_active_state(&priv->subdev);
> +
>  	rcsi2_stop(priv);
>  	usleep_range(1000, 2000);
> -	if (rcsi2_start(priv))
> +	if (rcsi2_start(priv, state))
>  		dev_warn(priv->dev, "Failed to restart CSI-2 receiver\n");
> -	mutex_unlock(&priv->lock);
> +
> +	v4l2_subdev_unlock_state(state);
> 
>  	return IRQ_HANDLED;
>  }
> @@ -1851,7 +1867,7 @@ static int rcsi2_probe(struct platform_device *pdev)
>  {
>  	const struct soc_device_attribute *attr;
>  	struct rcar_csi2 *priv;
> -	unsigned int i, num_pads;
> +	unsigned int i;
>  	int ret;
> 
>  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> @@ -1870,23 +1886,23 @@ static int rcsi2_probe(struct platform_device *pdev)
> 
>  	priv->dev = &pdev->dev;
> 
> -	mutex_init(&priv->lock);
>  	priv->stream_count = 0;
> 
>  	ret = rcsi2_probe_resources(priv, pdev);
>  	if (ret) {
>  		dev_err(priv->dev, "Failed to get resources\n");
> -		goto error_mutex;
> +		return ret;
>  	}
> 
>  	platform_set_drvdata(pdev, priv);
> 
>  	ret = rcsi2_parse_dt(priv);
>  	if (ret)
> -		goto error_mutex;
> +		return ret;
> 
>  	priv->subdev.owner = THIS_MODULE;
>  	priv->subdev.dev = &pdev->dev;
> +	priv->subdev.internal_ops = &rcar_csi2_internal_ops;
>  	v4l2_subdev_init(&priv->subdev, &rcar_csi2_subdev_ops);
>  	v4l2_set_subdevdata(&priv->subdev, &pdev->dev);
>  	snprintf(priv->subdev.name, sizeof(priv->subdev.name), "%s %s",
> @@ -1896,13 +1912,14 @@ static int rcsi2_probe(struct platform_device *pdev)
>  	priv->subdev.entity.function = MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER;
>  	priv->subdev.entity.ops = &rcar_csi2_entity_ops;
> 
> -	num_pads = priv->info->use_isp ? 2 : NR_OF_RCAR_CSI2_PAD;
> +	priv->num_pads = priv->info->use_isp ? NR_OF_RCAR_CSI2_ISP_PADS
> +					     : NR_OF_RCAR_CSI2_VIN_PADS;
> 
>  	priv->pads[RCAR_CSI2_SINK].flags = MEDIA_PAD_FL_SINK;
> -	for (i = RCAR_CSI2_SOURCE_VC0; i < num_pads; i++)
> +	for (i = RCAR_CSI2_SOURCE_VC0; i < priv->num_pads; i++)
>  		priv->pads[i].flags = MEDIA_PAD_FL_SOURCE;
> 
> -	ret = media_entity_pads_init(&priv->subdev.entity, num_pads,
> +	ret = media_entity_pads_init(&priv->subdev.entity, priv->num_pads,
>  				     priv->pads);
>  	if (ret)
>  		goto error_async;
> @@ -1912,21 +1929,25 @@ static int rcsi2_probe(struct platform_device *pdev)
> 
>  	pm_runtime_enable(&pdev->dev);
> 
> +	ret = v4l2_subdev_init_finalize(&priv->subdev);
> +	if (ret)
> +		goto error_pm_runtime;
> +
>  	ret = v4l2_async_register_subdev(&priv->subdev);
>  	if (ret < 0)
> -		goto error_pm_runtime;
> +		goto error_subdev;
> 
>  	dev_info(priv->dev, "%d lanes found\n", priv->lanes);
> 
>  	return 0;
> 
> +error_subdev:
> +	v4l2_subdev_cleanup(&priv->subdev);
>  error_pm_runtime:
>  	pm_runtime_disable(&pdev->dev);
>  error_async:
>  	v4l2_async_nf_unregister(&priv->notifier);
>  	v4l2_async_nf_cleanup(&priv->notifier);
> -error_mutex:
> -	mutex_destroy(&priv->lock);
> 
>  	return ret;
>  }
> @@ -1941,8 +1962,6 @@ static void rcsi2_remove(struct platform_device *pdev)
>  	v4l2_subdev_cleanup(&priv->subdev);
> 
>  	pm_runtime_disable(&pdev->dev);
> -
> -	mutex_destroy(&priv->lock);
>  }
> 
>  static struct platform_driver rcar_csi2_pdrv = {
> --
> 2.44.0
> 

-- 
Kind Regards,
Niklas Söderlund