Re: [PATCH v4 13/17] media: rzg2l-cru: video: Implement .link_validate() callback

[Laurent Pinchart]

Hi Prabhakar,

Thank you for the patch.

On Mon, Oct 07, 2024 at 07:48:35PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> 
> Implement the `.link_validate()` callback for the video node and move the
> format checking into this function. This change allows the removal of
> `rzg2l_cru_mc_validate_format()`.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
>  .../platform/renesas/rzg2l-cru/rzg2l-video.c  | 91 ++++++++++---------
>  1 file changed, 47 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> index ceb9012c9d70..385b4242db2f 100644
> --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> @@ -189,46 +189,6 @@ static void rzg2l_cru_buffer_queue(struct vb2_buffer *vb)
>  	spin_unlock_irqrestore(&cru->qlock, flags);
>  }
>  
> -static int rzg2l_cru_mc_validate_format(struct rzg2l_cru_dev *cru,
> -					struct v4l2_subdev *sd,
> -					struct media_pad *pad)
> -{
> -	struct v4l2_subdev_format fmt = {
> -		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> -	};
> -
> -	fmt.pad = pad->index;
> -	if (v4l2_subdev_call_state_active(sd, pad, get_fmt, &fmt))
> -		return -EPIPE;
> -
> -	switch (fmt.format.code) {
> -	case MEDIA_BUS_FMT_UYVY8_1X16:
> -		break;
> -	default:
> -		return -EPIPE;
> -	}
> -
> -	switch (fmt.format.field) {
> -	case V4L2_FIELD_TOP:
> -	case V4L2_FIELD_BOTTOM:
> -	case V4L2_FIELD_NONE:
> -	case V4L2_FIELD_INTERLACED_TB:
> -	case V4L2_FIELD_INTERLACED_BT:
> -	case V4L2_FIELD_INTERLACED:
> -	case V4L2_FIELD_SEQ_TB:
> -	case V4L2_FIELD_SEQ_BT:
> -		break;
> -	default:
> -		return -EPIPE;
> -	}
> -
> -	if (fmt.format.width != cru->format.width ||
> -	    fmt.format.height != cru->format.height)
> -		return -EPIPE;
> -
> -	return 0;
> -}
> -
>  static void rzg2l_cru_set_slot_addr(struct rzg2l_cru_dev *cru,
>  				    int slot, dma_addr_t addr)
>  {
> @@ -531,10 +491,6 @@ static int rzg2l_cru_set_stream(struct rzg2l_cru_dev *cru, int on)
>  		return stream_off_ret;
>  	}
>  
> -	ret = rzg2l_cru_mc_validate_format(cru, sd, pad);
> -	if (ret)
> -		return ret;
> -
>  	pipe = media_entity_pipeline(&sd->entity) ? : &cru->vdev.pipe;
>  	ret = video_device_pipeline_start(&cru->vdev, pipe);
>  	if (ret)
> @@ -995,6 +951,52 @@ static const struct v4l2_file_operations rzg2l_cru_fops = {
>  	.read		= vb2_fop_read,
>  };
>  
> +/* -----------------------------------------------------------------------------
> + * Media entity operations
> + */
> +
> +static int rzg2l_cru_video_link_validate(struct media_link *link)
> +{
> +	struct v4l2_subdev_format fmt = {
> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +	};
> +	const struct rzg2l_cru_ip_format *video_fmt;
> +	const struct rzg2l_cru_ip_format *ip_fmt;
> +	struct v4l2_subdev *subdev;
> +	struct rzg2l_cru_dev *cru;
> +	struct media_pad *remote;
> +	int ret;
> +
> +	remote = link->source;
> +	subdev = media_entity_to_v4l2_subdev(remote->entity);
> +	fmt.pad = remote->index;

	subdev = media_entity_to_v4l2_subdev(link->source->entity);
	fmt.pad = link->source->index;

and drop the remote variable. Or, if you prefer keeping it, rename it to
source.

> +	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
> +	if (ret < 0)
> +		return ret == -ENOIOCTLCMD ? -EINVAL : ret;
> +
> +	cru = container_of(media_entity_to_video_device(link->sink->entity),
> +			   struct rzg2l_cru_dev, vdev);
> +	video_fmt = rzg2l_cru_ip_format_to_fmt(cru->format.pixelformat);
> +	if (!video_fmt)
> +		return -EPIPE;

Can this happen, doesn't the s_fmt handler on the video device ensure
that pixelformat is always valid.

> +	ip_fmt = rzg2l_cru_ip_code_to_fmt(fmt.format.code);
> +	if (!ip_fmt)
> +		return -EPIPE;

Same question here.

> +
> +	if (fmt.format.width != cru->format.width ||
> +	    fmt.format.height != cru->format.height ||
> +	    fmt.format.field != cru->format.field ||
> +	    video_fmt->code != fmt.format.code ||
> +	    ip_fmt->format != cru->format.pixelformat)

The last two line seem to implement the same check.

> +		return -EPIPE;
> +
> +	return 0;
> +}
> +
> +static const struct media_entity_operations rzg2l_cru_video_media_ops = {
> +	.link_validate = rzg2l_cru_video_link_validate,
> +};
> +
>  static void rzg2l_cru_v4l2_init(struct rzg2l_cru_dev *cru)
>  {
>  	struct video_device *vdev = &cru->vdev;
> @@ -1006,6 +1008,7 @@ static void rzg2l_cru_v4l2_init(struct rzg2l_cru_dev *cru)
>  	vdev->lock = &cru->lock;
>  	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
>  	vdev->device_caps |= V4L2_CAP_IO_MC;
> +	vdev->entity.ops = &rzg2l_cru_video_media_ops;
>  	vdev->fops = &rzg2l_cru_fops;
>  	vdev->ioctl_ops = &rzg2l_cru_ioctl_ops;
>  

-- 
Regards,

Laurent Pinchart