alistair23-linux/include/drm/drm_fourcc.h

/*
 * Copyright (c) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */
#ifndef __DRM_FOURCC_H__
#define __DRM_FOURCC_H__

#include <linux/types.h>
#include <uapi/drm/drm_fourcc.h>

/*
 * DRM formats are little endian.  Define host endian variants for the
 * most common formats here, to reduce the #ifdefs needed in drivers.
 *
 * Note that the DRM_FORMAT_BIG_ENDIAN flag should only be used in
 * case the format can't be specified otherwise, so we don't end up
 * with two values describing the same format.
 */
#ifdef __BIG_ENDIAN
# define DRM_FORMAT_HOST_XRGB1555     (DRM_FORMAT_XRGB1555         |	\
				       DRM_FORMAT_BIG_ENDIAN)
# define DRM_FORMAT_HOST_RGB565       (DRM_FORMAT_RGB565           |	\
				       DRM_FORMAT_BIG_ENDIAN)
# define DRM_FORMAT_HOST_XRGB8888     DRM_FORMAT_BGRX8888
# define DRM_FORMAT_HOST_ARGB8888     DRM_FORMAT_BGRA8888
#else
# define DRM_FORMAT_HOST_XRGB1555     DRM_FORMAT_XRGB1555
# define DRM_FORMAT_HOST_RGB565       DRM_FORMAT_RGB565
# define DRM_FORMAT_HOST_XRGB8888     DRM_FORMAT_XRGB8888
# define DRM_FORMAT_HOST_ARGB8888     DRM_FORMAT_ARGB8888
#endif

struct drm_device;
struct drm_mode_fb_cmd2;

/**
 * struct drm_format_info - information about a DRM format
 */
struct drm_format_info {
	/** @format: 4CC format identifier (DRM_FORMAT_*) */
	u32 format;

	/**
	 * @depth:
	 *
	 * Color depth (number of bits per pixel excluding padding bits),
	 * valid for a subset of RGB formats only. This is a legacy field, do
	 * not use in new code and set to 0 for new formats.
	 */
	u8 depth;

	/** @num_planes: Number of color planes (1 to 3) */
	u8 num_planes;

	union {
		/**
		 * @cpp:
		 *
		 * Number of bytes per pixel (per plane), this is aliased with
		 * @char_per_block. It is deprecated in favour of using the
		 * triplet @char_per_block, @block_w, @block_h for better
		 * describing the pixel format.
		 */
		u8 cpp[3];

		/**
		 * @char_per_block:
		 *
		 * Number of bytes per block (per plane), where blocks are
		 * defined as a rectangle of pixels which are stored next to
		 * each other in a byte aligned memory region. Together with
		 * @block_w and @block_h this is used to properly describe tiles
		 * in tiled formats or to describe groups of pixels in packed
		 * formats for which the memory needed for a single pixel is not
		 * byte aligned.
		 *
		 * @cpp has been kept for historical reasons because there are
		 * a lot of places in drivers where it's used. In drm core for
		 * generic code paths the preferred way is to use
		 * @char_per_block, drm_format_info_block_width() and
		 * drm_format_info_block_height() which allows handling both
		 * block and non-block formats in the same way.
		 *
		 * For formats that are intended to be used only with non-linear
		 * modifiers both @cpp and @char_per_block must be 0 in the
		 * generic format table. Drivers could supply accurate
		 * information from their drm_mode_config.get_format_info hook
		 * if they want the core to be validating the pitch.
		 */
		u8 char_per_block[3];
	};

	/**
	 * @block_w:
	 *
	 * Block width in pixels, this is intended to be accessed through
	 * drm_format_info_block_width()
	 */
	u8 block_w[3];

	/**
	 * @block_h:
	 *
	 * Block height in pixels, this is intended to be accessed through
	 * drm_format_info_block_height()
	 */
	u8 block_h[3];

	/** @hsub: Horizontal chroma subsampling factor */
	u8 hsub;
	/** @vsub: Vertical chroma subsampling factor */
	u8 vsub;

	/** @has_alpha: Does the format embeds an alpha component? */
	bool has_alpha;

	/** @is_yuv: Is it a YUV format? */
	bool is_yuv;
};

/**
 * struct drm_format_name_buf - name of a DRM format
 * @str: string buffer containing the format name
 */
struct drm_format_name_buf {
	char str[32];
};

const struct drm_format_info *__drm_format_info(u32 format);
const struct drm_format_info *drm_format_info(u32 format);
const struct drm_format_info *
drm_get_format_info(struct drm_device *dev,
		    const struct drm_mode_fb_cmd2 *mode_cmd);
uint32_t drm_mode_legacy_fb_format(uint32_t bpp, uint32_t depth);
uint32_t drm_driver_legacy_fb_format(struct drm_device *dev,
				     uint32_t bpp, uint32_t depth);
int drm_format_num_planes(uint32_t format);
int drm_format_plane_cpp(uint32_t format, int plane);
int drm_format_horz_chroma_subsampling(uint32_t format);
int drm_format_vert_chroma_subsampling(uint32_t format);
int drm_format_plane_width(int width, uint32_t format, int plane);
int drm_format_plane_height(int height, uint32_t format, int plane);
unsigned int drm_format_info_block_width(const struct drm_format_info *info,
					 int plane);
unsigned int drm_format_info_block_height(const struct drm_format_info *info,
					  int plane);
uint64_t drm_format_info_min_pitch(const struct drm_format_info *info,
				   int plane, unsigned int buffer_width);
const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf *buf);

#endif /* __DRM_FOURCC_H__ */