text: /*
   * 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;
  
  	switch (bpp) {
  	case 8:
  		fmt = DRM_FORMAT_C8;
  		break;
  	case 16:
  		if (depth == 15)
  			fmt = DRM_FORMAT_XRGB1555;
  		else
  			fmt = DRM_FORMAT_RGB565;
  		break;
  	case 24:
  		fmt = DRM_FORMAT_RGB888;
  		break;
  	case 32:
  		if (depth == 24)
  			fmt = DRM_FORMAT_XRGB8888;
  		else if (depth == 30)
  			fmt = DRM_FORMAT_XRGB2101010;
  		else
  			fmt = DRM_FORMAT_ARGB8888;
  		break;
  	default:
  		DRM_ERROR("bad bpp, assuming x8r8g8b8 pixel format\n");
  		fmt = DRM_FORMAT_XRGB8888;
  		break;
  	}
  
  	return fmt;
  }
  EXPORT_SYMBOL(drm_mode_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_AYUV,		.depth = 0,  .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1, .has_alpha = true, .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);
  