Re: [PATCH v2 16/23] staging: media: tegra-video: tegra20: simplify format align calculations

[Mikko Perttunen <mperttunen@nvidia.com>]

On Saturday, September 6, 2025 10:53 PM Svyatoslav Ryhel wrote:
> Simplify format align calculations by slightly modifying supported formats
> structure.
> 
> Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
> ---
>  drivers/staging/media/tegra-video/tegra20.c | 41 ++++++++-------------
>  1 file changed, 16 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/staging/media/tegra-video/tegra20.c b/drivers/staging/media/tegra-video/tegra20.c
> index 6e0b3b728623..781c4e8ec856 100644
> --- a/drivers/staging/media/tegra-video/tegra20.c
> +++ b/drivers/staging/media/tegra-video/tegra20.c
> @@ -280,20 +280,8 @@ static void tegra20_fmt_align(struct v4l2_pix_format *pix, unsigned int bpp)
>  	pix->width  = clamp(pix->width,  TEGRA20_MIN_WIDTH,  TEGRA20_MAX_WIDTH);
>  	pix->height = clamp(pix->height, TEGRA20_MIN_HEIGHT, TEGRA20_MAX_HEIGHT);
>  
> -	switch (pix->pixelformat) {
> -	case V4L2_PIX_FMT_UYVY:
> -	case V4L2_PIX_FMT_VYUY:
> -	case V4L2_PIX_FMT_YUYV:
> -	case V4L2_PIX_FMT_YVYU:
> -		pix->bytesperline = roundup(pix->width, 2) * 2;
> -		pix->sizeimage = roundup(pix->width, 2) * 2 * pix->height;
> -		break;
> -	case V4L2_PIX_FMT_YUV420:
> -	case V4L2_PIX_FMT_YVU420:
> -		pix->bytesperline = roundup(pix->width, 8);
> -		pix->sizeimage = roundup(pix->width, 8) * pix->height * 3 / 2;
> -		break;
> -	}
> +	pix->bytesperline = DIV_ROUND_UP(pix->width * bpp, 8);

Assuming the bpp is coming from the format table below, this changes the value of bytesperline for planar formats. With this it'll be (width * 12) / 8 i.e. width * 3/2, which doesn't sound right.

> +	pix->sizeimage = pix->bytesperline * pix->height;
>  }
>  
>  /*
> @@ -576,20 +564,23 @@ static const struct tegra_vi_ops tegra20_vi_ops = {
>  	.vi_stop_streaming = tegra20_vi_stop_streaming,
>  };
>  
> -#define TEGRA20_VIDEO_FMT(MBUS_CODE, BPP, FOURCC)	\
> -{							\
> -	.code    = MEDIA_BUS_FMT_##MBUS_CODE,		\
> -	.bpp     = BPP,					\
> -	.fourcc  = V4L2_PIX_FMT_##FOURCC,		\
> +#define TEGRA20_VIDEO_FMT(DATA_TYPE, BIT_WIDTH, MBUS_CODE, BPP, FOURCC)	\
> +{									\
> +	.img_dt		= TEGRA_IMAGE_DT_##DATA_TYPE,			\
> +	.bit_width	= BIT_WIDTH,					\
> +	.code		= MEDIA_BUS_FMT_##MBUS_CODE,			\
> +	.bpp		= BPP,						\
> +	.fourcc		= V4L2_PIX_FMT_##FOURCC,			\
>  }
>  
>  static const struct tegra_video_format tegra20_video_formats[] = {
> -	TEGRA20_VIDEO_FMT(UYVY8_2X8, 2, UYVY),
> -	TEGRA20_VIDEO_FMT(VYUY8_2X8, 2, VYUY),
> -	TEGRA20_VIDEO_FMT(YUYV8_2X8, 2, YUYV),
> -	TEGRA20_VIDEO_FMT(YVYU8_2X8, 2, YVYU),
> -	TEGRA20_VIDEO_FMT(UYVY8_2X8, 1, YUV420),
> -	TEGRA20_VIDEO_FMT(UYVY8_2X8, 1, YVU420),
> +	/* YUV422 */
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, UYVY8_2X8, 16, UYVY),
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, VYUY8_2X8, 16, VYUY),
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, YUYV8_2X8, 16, YUYV),
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, YVYU8_2X8, 16, YVYU),
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, UYVY8_2X8, 12, YUV420),
> +	TEGRA20_VIDEO_FMT(YUV422_8, 16, UYVY8_2X8, 12, YVU420),
>  };
>  
>  const struct tegra_vi_soc tegra20_vi_soc = {
>