drivers/gpu/drm/drm_fourcc.c

/*
 * Copyright (c) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *
 * DRM core format related functions
 *
 * 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.
 */

#include <linux/bug.h>
#include <linux/ctype.h>
#include <linux/export.h>
#include <linux/kernel.h>

#include <drm/drmP.h>
#include <drm/drm_fourcc.h>

static char printable_char(int c)
{
	return isascii(c) && isprint(c) ? c : '?';
}

/**
 * drm_mode_legacy_fb_format - compute drm fourcc code from legacy description
 * @bpp: bits per pixels
 * @depth: bit depth per pixel
 *
 * Computes a drm fourcc pixel format code for the given @bpp/@depth values.
 * Useful in fbdev emulation code, since that deals in those values.
 */
uint32_t drm_mode_legacy_fb_format(uint32_t bpp, uint32_t depth)
{
	uint32_t fmt = DRM_FORMAT_INVALID;

	switch (bpp) {
	case 8:
		if (depth == 8)
			fmt = DRM_FORMAT_C8;
		break;

	case 16:
		switch (depth) {
		case 15:
			fmt = DRM_FORMAT_XRGB1555;
			break;
		case 16:
			fmt = DRM_FORMAT_RGB565;
			break;
		default:
			break;
		}
		break;

	case 24:
		if (depth == 24)
			fmt = DRM_FORMAT_RGB888;
		break;

	case 32:
		switch (depth) {
		case 24:
			fmt = DRM_FORMAT_XRGB8888;
			break;
		case 30:
			fmt = DRM_FORMAT_XRGB2101010;
			break;
		case 32:
			fmt = DRM_FORMAT_ARGB8888;
			break;
		default:
			break;
		}
		break;

	default:
		break;
	}

	return fmt;
}
EXPORT_SYMBOL(drm_mode_legacy_fb_format);

/**
 * drm_driver_legacy_fb_format - compute drm fourcc code from legacy description
 * @dev: DRM device
 * @bpp: bits per pixels
 * @depth: bit depth per pixel
 *
 * Computes a drm fourcc pixel format code for the given @bpp/@depth values.
 * Unlike drm_mode_legacy_fb_format() this looks at the drivers mode_config,
 * and depending on the &drm_mode_config.quirk_addfb_prefer_host_byte_order flag
 * it returns little endian byte order or host byte order framebuffer formats.
 */
uint32_t drm_driver_legacy_fb_format(struct drm_device *dev,
				     uint32_t bpp, uint32_t depth)
{
	uint32_t fmt = drm_mode_legacy_fb_format(bpp, depth);

	if (dev->mode_config.quirk_addfb_prefer_host_byte_order) {
		if (fmt == DRM_FORMAT_XRGB8888)
			fmt = DRM_FORMAT_HOST_XRGB8888;
		if (fmt == DRM_FORMAT_ARGB8888)
			fmt = DRM_FORMAT_HOST_ARGB8888;
		if (fmt == DRM_FORMAT_RGB565)
			fmt = DRM_FORMAT_HOST_RGB565;
		if (fmt == DRM_FORMAT_XRGB1555)
			fmt = DRM_FORMAT_HOST_XRGB1555;
	}

	if (dev->mode_config.quirk_addfb_prefer_xbgr_30bpp &&
	    fmt == DRM_FORMAT_XRGB2101010)
		fmt = DRM_FORMAT_XBGR2101010;

	return fmt;
}
EXPORT_SYMBOL(drm_driver_legacy_fb_format);

/**
 * drm_get_format_name - fill a string with a drm fourcc format's name
 * @format: format to compute name of
 * @buf: caller-supplied buffer
 */
const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf *buf)
{
	snprintf(buf->str, sizeof(buf->str),
		 "%c%c%c%c %s-endian (0x%08x)",
		 printable_char(format & 0xff),
		 printable_char((format >> 8) & 0xff),
		 printable_char((format >> 16) & 0xff),
		 printable_char((format >> 24) & 0x7f),
		 format & DRM_FORMAT_BIG_ENDIAN ? "big" : "little",
		 format);

	return buf->str;
}
EXPORT_SYMBOL(drm_get_format_name);

/*
 * Internal function to query information for a given format. See
 * drm_format_info() for the public API.
 */
const struct drm_format_info *__drm_format_info(u32 format)
{
	static const struct drm_format_info formats[] = {
		{ .format = DRM_FORMAT_C8,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGB332,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGR233,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XRGB4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XBGR4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGBX4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGRX4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_ARGB4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_ABGR4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGBA4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGRA4444,	.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_XRGB1555,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XBGR1555,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGBX5551,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGRX5551,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_ARGB1555,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_ABGR1555,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGBA5551,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGRA5551,	.depth = 15, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGB565,		.depth = 16, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGR565,		.depth = 16, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGB888,		.depth = 24, .num_planes = 1, .cpp = { 3, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGR888,		.depth = 24, .num_planes = 1, .cpp = { 3, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XRGB8888,	.depth = 24, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XBGR8888,	.depth = 24, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGBX8888,	.depth = 24, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGRX8888,	.depth = 24, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGB565_A8,	.depth = 24, .num_planes = 2, .cpp = { 2, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGR565_A8,	.depth = 24, .num_planes = 2, .cpp = { 2, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_XRGB2101010,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_XBGR2101010,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_RGBX1010102,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_BGRX1010102,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
		{ .format = DRM_FORMAT_ARGB2101010,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_ABGR2101010,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGBA1010102,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGRA1010102,	.depth = 30, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_ARGB8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_ABGR8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGBA8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGRA8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGB888_A8,	.depth = 32, .num_planes = 2, .cpp = { 3, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGR888_A8,	.depth = 32, .num_planes = 2, .cpp = { 3, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_XRGB8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_XBGR8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_RGBX8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_BGRX8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true },
		{ .format = DRM_FORMAT_YUV410,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 4, .is_yuv = true },
		{ .format = DRM_FORMAT_YVU410,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 4, .is_yuv = true },
		{ .format = DRM_FORMAT_YUV411,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YVU411,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YUV420,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_YVU420,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_YUV422,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YVU422,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YUV444,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YVU444,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_NV12,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_NV21,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_NV16,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_NV61,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_NV24,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_NV42,		.depth = 0,  .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YUYV,		.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_YVYU,		.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_UYVY,		.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_VYUY,		.depth = 0,  .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_XYUV8888,	.depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_AYUV,		.depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true, .is_yuv = true },
		{ .format = DRM_FORMAT_Y210,            .depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y212,            .depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y216,            .depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y410,            .depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y412,            .depth = 0,  .num_planes = 1, .cpp = { 8, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y416,            .depth = 0,  .num_planes = 1, .cpp = { 8, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true },
		{ .format = DRM_FORMAT_Y0L0,		.depth = 0,  .num_planes = 1,
		  .char_per_block = { 8, 0, 0 }, .block_w = { 2, 0, 0 }, .block_h = { 2, 0, 0 },
		  .hsub = 2, .vsub = 2, .has_alpha = true, .is_yuv = true },
		{ .format = DRM_FORMAT_X0L0,		.depth = 0,  .num_planes = 1,
		  .char_per_block = { 8, 0, 0 }, .block_w = { 2, 0, 0 }, .block_h = { 2, 0, 0 },
		  .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_Y0L2,		.depth = 0,  .num_planes = 1,
		  .char_per_block = { 8, 0, 0 }, .block_w = { 2, 0, 0 }, .block_h = { 2, 0, 0 },
		  .hsub = 2, .vsub = 2, .has_alpha = true, .is_yuv = true },
		{ .format = DRM_FORMAT_X0L2,		.depth = 0,  .num_planes = 1,
		  .char_per_block = { 8, 0, 0 }, .block_w = { 2, 0, 0 }, .block_h = { 2, 0, 0 },
		  .hsub = 2, .vsub = 2, .is_yuv = true },
		{ .format = DRM_FORMAT_P010,            .depth = 0,  .num_planes = 2,
		  .char_per_block = { 2, 4, 0 }, .block_w = { 1, 0, 0 }, .block_h = { 1, 0, 0 },
		  .hsub = 2, .vsub = 2, .is_yuv = true},
		{ .format = DRM_FORMAT_P012,		.depth = 0,  .num_planes = 2,
		  .char_per_block = { 2, 4, 0 }, .block_w = { 1, 0, 0 }, .block_h = { 1, 0, 0 },
		   .hsub = 2, .vsub = 2, .is_yuv = true},
		{ .format = DRM_FORMAT_P016,		.depth = 0,  .num_planes = 2,
		  .char_per_block = { 2, 4, 0 }, .block_w = { 1, 0, 0 }, .block_h = { 1, 0, 0 },
		  .hsub = 2, .vsub = 2, .is_yuv = true},
	};

	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
		if (formats[i].format == format)
			return &formats[i];
	}

	return NULL;
}

/**
 * drm_format_info - query information for a given format
 * @format: pixel format (DRM_FORMAT_*)
 *
 * 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 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)
{
	const struct drm_format_info *info;

	info = __drm_format_info(format);
	WARN_ON(!info);
	return info;
}
EXPORT_SYMBOL(drm_format_info);

/**
 * drm_get_format_info - query information for a given framebuffer configuration
 * @dev: DRM device
 * @mode_cmd: metadata from the userspace fb creation request
 *
 * 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_get_format_info(struct drm_device *dev,
		    const struct drm_mode_fb_cmd2 *mode_cmd)
{
	const struct drm_format_info *info = NULL;

	if (dev->mode_config.funcs->get_format_info)
		info = dev->mode_config.funcs->get_format_info(mode_cmd);

	if (!info)
		info = drm_format_info(mode_cmd->pixel_format);

	return info;
}
EXPORT_SYMBOL(drm_get_format_info);

/**
 * drm_format_num_planes - get the number of planes for format
 * @format: pixel format (DRM_FORMAT_*)
 *
 * Returns:
 * The number of planes used by the specified pixel format.
 */
int drm_format_num_planes(uint32_t format)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	return info ? info->num_planes : 1;
}
EXPORT_SYMBOL(drm_format_num_planes);

/**
 * drm_format_plane_cpp - determine the bytes per pixel value
 * @format: pixel format (DRM_FORMAT_*)
 * @plane: plane index
 *
 * Returns:
 * The bytes per pixel value for the specified plane.
 */
int drm_format_plane_cpp(uint32_t format, int plane)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	if (!info || plane >= info->num_planes)
		return 0;

	return info->cpp[plane];
}
EXPORT_SYMBOL(drm_format_plane_cpp);

/**
 * drm_format_horz_chroma_subsampling - get the horizontal chroma subsampling factor
 * @format: pixel format (DRM_FORMAT_*)
 *
 * Returns:
 * The horizontal chroma subsampling factor for the
 * specified pixel format.
 */
int drm_format_horz_chroma_subsampling(uint32_t format)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	return info ? info->hsub : 1;
}
EXPORT_SYMBOL(drm_format_horz_chroma_subsampling);

/**
 * drm_format_vert_chroma_subsampling - get the vertical chroma subsampling factor
 * @format: pixel format (DRM_FORMAT_*)
 *
 * Returns:
 * The vertical chroma subsampling factor for the
 * specified pixel format.
 */
int drm_format_vert_chroma_subsampling(uint32_t format)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	return info ? info->vsub : 1;
}
EXPORT_SYMBOL(drm_format_vert_chroma_subsampling);

/**
 * drm_format_plane_width - width of the plane given the first plane
 * @width: width of the first plane
 * @format: pixel format
 * @plane: plane index
 *
 * Returns:
 * The width of @plane, given that the width of the first plane is @width.
 */
int drm_format_plane_width(int width, uint32_t format, int plane)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	if (!info || plane >= info->num_planes)
		return 0;

	if (plane == 0)
		return width;

	return width / info->hsub;
}
EXPORT_SYMBOL(drm_format_plane_width);

/**
 * drm_format_plane_height - height of the plane given the first plane
 * @height: height of the first plane
 * @format: pixel format
 * @plane: plane index
 *
 * Returns:
 * The height of @plane, given that the height of the first plane is @height.
 */
int drm_format_plane_height(int height, uint32_t format, int plane)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	if (!info || plane >= info->num_planes)
		return 0;

	if (plane == 0)
		return height;

	return height / info->vsub;
}
EXPORT_SYMBOL(drm_format_plane_height);

/**
 * drm_format_info_block_width - width in pixels of block.
 * @info: pixel format info
 * @plane: plane index
 *
 * Returns:
 * The width in pixels of a block, depending on the plane index.
 */
unsigned int drm_format_info_block_width(const struct drm_format_info *info,
					 int plane)
{
	if (!info || plane < 0 || plane >= info->num_planes)
		return 0;

	if (!info->block_w[plane])
		return 1;
	return info->block_w[plane];
}
EXPORT_SYMBOL(drm_format_info_block_width);

/**
 * drm_format_info_block_height - height in pixels of a block
 * @info: pixel format info
 * @plane: plane index
 *
 * Returns:
 * The height in pixels of a block, depending on the plane index.
 */
unsigned int drm_format_info_block_height(const struct drm_format_info *info,
					  int plane)
{
	if (!info || plane < 0 || plane >= info->num_planes)
		return 0;

	if (!info->block_h[plane])
		return 1;
	return info->block_h[plane];
}
EXPORT_SYMBOL(drm_format_info_block_height);

/**
 * drm_format_info_min_pitch - computes the minimum required pitch in bytes
 * @info: pixel format info
 * @plane: plane index
 * @buffer_width: buffer width in pixels
 *
 * Returns:
 * The minimum required pitch in bytes for a buffer by taking into consideration
 * the pixel format information and the buffer width.
 */
uint64_t drm_format_info_min_pitch(const struct drm_format_info *info,
				   int plane, unsigned int buffer_width)
{
	if (!info || plane < 0 || plane >= info->num_planes)
		return 0;

	return DIV_ROUND_UP_ULL((u64)buffer_width * info->char_per_block[plane],
			    drm_format_info_block_width(info, plane) *
			    drm_format_info_block_height(info, plane));
}
EXPORT_SYMBOL(drm_format_info_min_pitch);