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Message-ID: <d8f4a31e35b1702230ced4a0cb43c10d1c7e60c8.camel@ndufresne.ca>
Subject: Re: [RFC PATCH 18/20] lib: image-formats: Add v4l2 formats support
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Maxime Ripard <maxime.ripard@bootlin.com>,
        Daniel Vetter <daniel.vetter@intel.com>,
        David Airlie <airlied@linux.ie>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>
Cc:     Sakari Ailus <sakari.ailus@linux.intel.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org
Date:   Tue, 19 Mar 2019 19:29:18 -0400
In-Reply-To: <c97024b97d3261dcf41aad3c8bc1c5d9906f33c9.1553032382.git-series.maxime.ripard@bootlin.com>
References: <cover.92acdec88ee4c280cb74e08ea22f0075e5fa055c.1553032382.git-series.maxime.ripard@bootlin.com>
         <c97024b97d3261dcf41aad3c8bc1c5d9906f33c9.1553032382.git-series.maxime.ripard@bootlin.com>
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Le mardi 19 mars 2019 à 22:57 +0100, Maxime Ripard a écrit :
> V4L2 uses different fourcc's than DRM, and has a different set of formats.
> For now, let's add the v4l2 fourcc's for the already existing formats.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  include/linux/image-formats.h |  9 +++++-
>  lib/image-formats.c           | 67 ++++++++++++++++++++++++++++++++++++-
>  2 files changed, 76 insertions(+)
> 
> diff --git a/include/linux/image-formats.h b/include/linux/image-formats.h
> index 53fd73a71b3d..fbc3a4501ebd 100644
> --- a/include/linux/image-formats.h
> +++ b/include/linux/image-formats.h
> @@ -26,6 +26,13 @@ struct image_format_info {
>  	};
>  
>  	/**
> +	 * @v4l2_fmt:
> +	 *
> +	 * V4L2 4CC format identifier (V4L2_PIX_FMT_*)
> +	 */
> +	u32 v4l2_fmt;
> +
> +	/**
>  	 * @depth:
>  	 *
>  	 * Color depth (number of bits per pixel excluding padding bits),
> @@ -222,6 +229,8 @@ image_format_info_is_yuv_sampling_444(const struct image_format_info *info)
>  
>  const struct image_format_info *__image_format_drm_lookup(u32 drm);
>  const struct image_format_info *image_format_drm_lookup(u32 drm);
> +const struct image_format_info *__image_format_v4l2_lookup(u32 v4l2);
> +const struct image_format_info *image_format_v4l2_lookup(u32 v4l2);
>  unsigned int image_format_plane_cpp(const struct image_format_info *format,
>  				    int plane);
>  unsigned int image_format_plane_width(int width,
> diff --git a/lib/image-formats.c b/lib/image-formats.c
> index 9b9a73220c5d..39f1d38ae861 100644
> --- a/lib/image-formats.c
> +++ b/lib/image-formats.c
> @@ -8,6 +8,7 @@
>  static const struct image_format_info formats[] = {
>  	{
>  		.drm_fmt = DRM_FORMAT_C8,
> +		.v4l2_fmt = V4L2_PIX_FMT_GREY,
>  		.depth = 8,
>  		.num_planes = 1,
>  		.cpp = { 1, 0, 0 },
> @@ -15,6 +16,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_RGB332,
> +		.v4l2_fmt = V4L2_PIX_FMT_RGB332,
>  		.depth = 8,
>  		.num_planes = 1,
>  		.cpp = { 1, 0, 0 },
> @@ -29,6 +31,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_XRGB4444,
> +		.v4l2_fmt = V4L2_PIX_FMT_XRGB444,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -57,6 +60,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_ARGB4444,
> +		.v4l2_fmt = V4L2_PIX_FMT_ARGB444,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -89,6 +93,7 @@ static const struct image_format_info formats[] = {
>  		.has_alpha = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_XRGB1555,
> +		.v4l2_fmt = V4L2_PIX_FMT_XRGB555,
>  		.depth = 15,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -117,6 +122,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_ARGB1555,
> +		.v4l2_fmt = V4L2_PIX_FMT_ARGB555,
>  		.depth = 15,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -149,6 +155,7 @@ static const struct image_format_info formats[] = {
>  		.has_alpha = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_RGB565,
> +		.v4l2_fmt = V4L2_PIX_FMT_RGB565,
>  		.depth = 16,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -163,6 +170,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_RGB888,
> +		.v4l2_fmt = V4L2_PIX_FMT_RGB24,
>  		.depth = 24,
>  		.num_planes = 1,
>  		.cpp = { 3, 0, 0 },
> @@ -170,6 +178,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_BGR888,
> +		.v4l2_fmt = V4L2_PIX_FMT_BGR24,
>  		.depth = 24,
>  		.num_planes = 1,
>  		.cpp = { 3, 0, 0 },
> @@ -177,6 +186,7 @@ static const struct image_format_info formats[] = {
>  		.vsub = 1,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_XRGB8888,
> +		.v4l2_fmt = V4L2_PIX_FMT_XRGB32,


All RGB mapping should be surrounded by ifdef, because many (not all)
DRM formats represent the order of component when placed in a CPU
register, unlike V4L2 which uses memory order. I've pick this one
randomly, but this one on most system, little endian, will match
V4L2_PIX_FMT_XBGR32. This type of complex mapping can be found in
multiple places, notably in GStreamer:

https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/blob/master/sys/kms/gstkmsutils.c#L45

>  		.depth = 24,
>  		.num_planes = 1,
>  		.cpp = { 4, 0, 0 },
> @@ -281,6 +291,7 @@ static const struct image_format_info formats[] = {
>  		.has_alpha = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_ARGB8888,
> +		.v4l2_fmt = V4L2_PIX_FMT_ARGB32,
>  		.depth = 32,
>  		.num_planes = 1,
>  		.cpp = { 4, 0, 0 },
> @@ -361,6 +372,7 @@ static const struct image_format_info formats[] = {
>  		.has_alpha = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YUV410,
> +		.v4l2_fmt = V4L2_PIX_FMT_YUV410,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -369,6 +381,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YVU410,
> +		.v4l2_fmt = V4L2_PIX_FMT_YVU410,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -393,6 +406,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YUV420,
> +		.v4l2_fmt = V4L2_PIX_FMT_YUV420M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -401,6 +415,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YVU420,
> +		.v4l2_fmt = V4L2_PIX_FMT_YVU420M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -409,6 +424,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YUV422,
> +		.v4l2_fmt = V4L2_PIX_FMT_YUV422M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -417,6 +433,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YVU422,
> +		.v4l2_fmt = V4L2_PIX_FMT_YVU422M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -425,6 +442,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YUV444,
> +		.v4l2_fmt = V4L2_PIX_FMT_YUV444M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -433,6 +451,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YVU444,
> +		.v4l2_fmt = V4L2_PIX_FMT_YVU444M,
>  		.depth = 0,
>  		.num_planes = 3,
>  		.cpp = { 1, 1, 1 },
> @@ -441,6 +460,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV12,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV12,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -449,6 +469,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV21,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV21,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -457,6 +478,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV16,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV16,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -465,6 +487,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV61,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV61,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -473,6 +496,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV24,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV24,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -481,6 +505,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_NV42,
> +		.v4l2_fmt = V4L2_PIX_FMT_NV42,
>  		.depth = 0,
>  		.num_planes = 2,
>  		.cpp = { 1, 2, 0 },
> @@ -489,6 +514,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YUYV,
> +		.v4l2_fmt = V4L2_PIX_FMT_YUYV,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -497,6 +523,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_YVYU,
> +		.v4l2_fmt = V4L2_PIX_FMT_YVYU,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -505,6 +532,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_UYVY,
> +		.v4l2_fmt = V4L2_PIX_FMT_UYVY,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -513,6 +541,7 @@ static const struct image_format_info formats[] = {
>  		.is_yuv = true,
>  	}, {
>  		.drm_fmt = DRM_FORMAT_VYUY,
> +		.v4l2_fmt = V4L2_PIX_FMT_VYUY,
>  		.depth = 0,
>  		.num_planes = 1,
>  		.cpp = { 2, 0, 0 },
> @@ -632,6 +661,44 @@ const struct image_format_info *image_format_drm_lookup(u32 drm)
>  EXPORT_SYMBOL(image_format_drm_lookup);
>  
>  /**
> + * __image_format_v4l2_lookup - query information for a given format
> + * @v4l2: V4L2 fourcc pixel format (V4L2_PIX_FMT_*)
> + *
> + * The caller should only pass a supported pixel format to this function.
> + *
> + * Returns:
> + * The instance of struct image_format_info that describes the pixel format, or
> + * NULL if the format is unsupported.
> + */
> +const struct image_format_info *__image_format_v4l2_lookup(u32 v4l2)
> +{
> +	return __image_format_lookup(v4l2_fmt, v4l2);
> +}
> +EXPORT_SYMBOL(__image_format_v4l2_lookup);
> +
> +/**
> + * image_format_v4l2_lookup - query information for a given format
> + * @v4l2: V4L2 fourcc pixel format (V4L2_PIX_FMT_*)
> + *
> + * The caller should only pass a supported pixel format to this function.
> + * Unsupported pixel formats will generate a warning in the kernel log.
> + *
> + * Returns:
> + * The instance of struct image_format_info that describes the pixel format, or
> + * NULL if the format is unsupported.
> + */
> +const struct image_format_info *image_format_v4l2_lookup(u32 v4l2)
> +{
> +	const struct image_format_info *format;
> +
> +	format = __image_format_v4l2_lookup(v4l2);
> +
> +	WARN_ON(!format);
> +	return format;
> +}
> +EXPORT_SYMBOL(image_format_v4l2_lookup);
> +
> +/**
>   * image_format_plane_cpp - determine the bytes per pixel value
>   * @format: pointer to the image_format
>   * @plane: plane index