[PATCH 1/4] drm: Centralize format information

[Tomi Valkeinen]

On 07/06/16 02:33, Laurent Pinchart wrote:
> Various pieces of information about DRM formats (number of planes, color
> depth, chroma subsampling, ...) are scattered across different helper
> functions in the DRM core. Callers of those functions often need to
> access more than a single parameter of the format, leading to
> inefficiencies due to multiple lookups.
> 
> Centralize all format information in a data structure and create a
> function to look up information based on the format 4CC.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  drivers/gpu/drm/drm_crtc.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_crtc.h     | 21 ++++++++++++
>  2 files changed, 104 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 0e3cc66aa8b7..74b0c6dd80cd 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -5544,6 +5544,89 @@ int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
>  }
>  
>  /**
> + * drm_format_info - information for a given format
> + * @format: pixel format (DRM_FORMAT_*)
> + *
> + * Returns:
> + * The instance of struct drm_format_info that describes the pixel format, or
> + * NULL if the format is unsupported.
> + */
> +const struct drm_format_info *drm_format_info(u32 format)
> +{
> +	static const struct drm_format_info formats[] = {
> +		{ DRM_FORMAT_C8, 8, 8, 1, { 1 }, 1, 1 },
> +		{ DRM_FORMAT_RGB332, 8, 8, 1, { 1 }, 1, 1 },
> +		{ DRM_FORMAT_BGR233, 8, 8, 1, { 1 }, 1, 1 },
> +		{ DRM_FORMAT_XRGB4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_XBGR4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGBX4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_BGRX4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_ARGB4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_ABGR4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGBA4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_BGRA4444, 12, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_XRGB1555, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_XBGR1555, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGBX5551, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_BGRX5551, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_ARGB1555, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_ABGR1555, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGBA5551, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_BGRA5551, 15, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGB565, 16, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_BGR565, 16, 16, 1, { 2 }, 1, 1 },
> +		{ DRM_FORMAT_RGB888, 24, 24, 1, { 3 }, 1, 1 },
> +		{ DRM_FORMAT_BGR888, 24, 24, 1, { 3 }, 1, 1 },
> +		{ DRM_FORMAT_XRGB8888, 24, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_XBGR8888, 24, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_RGBX8888, 24, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_BGRX8888, 24, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_XRGB2101010, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_XBGR2101010, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_RGBX1010102, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_BGRX1010102, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_ARGB2101010, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_ABGR2101010, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_RGBA1010102, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_BGRA1010102, 30, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_ARGB8888, 32, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_ABGR8888, 32, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_RGBA8888, 32, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_BGRA8888, 32, 32, 1, { 4 }, 1, 1 },
> +		{ DRM_FORMAT_YUV410, 0, 0, 3, { 1, 1, 1 }, 4, 4 },
> +		{ DRM_FORMAT_YVU410, 0, 0, 3, { 1, 1, 1 }, 4, 4 },
> +		{ DRM_FORMAT_YUV411, 0, 0, 3, { 1, 1, 1 }, 4, 1 },
> +		{ DRM_FORMAT_YVU411, 0, 0, 3, { 1, 1, 1 }, 4, 1 },
> +		{ DRM_FORMAT_YUV420, 0, 0, 3, { 1, 1, 1 }, 2, 2 },
> +		{ DRM_FORMAT_YVU420, 0, 0, 3, { 1, 1, 1 }, 2, 2 },
> +		{ DRM_FORMAT_YUV422, 0, 0, 3, { 1, 1, 1 }, 2, 1 },
> +		{ DRM_FORMAT_YVU422, 0, 0, 3, { 1, 1, 1 }, 2, 1 },
> +		{ DRM_FORMAT_YUV444, 0, 0, 3, { 1, 1, 1 }, 1, 1 },
> +		{ DRM_FORMAT_YVU444, 0, 0, 3, { 1, 1, 1 }, 1, 1 },
> +		{ DRM_FORMAT_NV12, 0, 0, 2, { 1, 2 }, 2, 2 },
> +		{ DRM_FORMAT_NV21, 0, 0, 2, { 1, 2 }, 2, 2 },
> +		{ DRM_FORMAT_NV16, 0, 0, 2, { 1, 2 }, 2, 1 },
> +		{ DRM_FORMAT_NV61, 0, 0, 2, { 1, 2 }, 2, 1 },
> +		{ DRM_FORMAT_NV24, 0, 0, 2, { 1, 2 }, 1, 1 },
> +		{ DRM_FORMAT_NV42, 0, 0, 2, { 1, 2 }, 1, 1 },
> +		{ DRM_FORMAT_YUYV, 0, 0, 1, { 2 }, 2, 1 },
> +		{ DRM_FORMAT_YVYU, 0, 0, 1, { 2 }, 2, 1 },
> +		{ DRM_FORMAT_UYVY, 0, 0, 1, { 2 }, 2, 1 },
> +		{ DRM_FORMAT_VYUY, 0, 0, 1, { 2 }, 2, 1 },
> +		{ DRM_FORMAT_AYUV, 0, 0, 1, { 4 }, 1, 1 },
> +	};
> +
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
> +		if (formats[i].format == format)
> +			return &formats[i];
> +	}
> +
> +	return NULL;

After looking at the third patch, I wonder if it would make sense to
give a warning here if the format was not found. In the third patch many
of the helpers will quietly return a valid value for unknown modes.
Which is what they do at the moment too, but is there ever a valid
reason to do that without something being wrong?

 Tomi

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