drivers/gpu/drm/drm_format_internal.h

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/drm_format_internal.h

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/drm_format_internal.h
Extension
.h
Size
4504 bytes
Lines
175
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef DRM_FORMAT_INTERNAL_H
#define DRM_FORMAT_INTERNAL_H

#include <linux/bits.h>
#include <linux/types.h>
#include <linux/swab.h>

/*
 * Each pixel-format conversion helper takes a raw pixel in a
 * specific input format and returns a raw pixel in a specific
 * output format. All pixels are in little-endian byte order.
 *
 * Function names are
 *
 *   drm_pixel_<input>_to_<output>_<algorithm>()
 *
 * where <input> and <output> refer to pixel formats. The
 * <algorithm> is optional and hints to the method used for the
 * conversion. Helpers with no algorithm given apply pixel-bit
 * shifting.
 *
 * The argument type is u32. We expect this to be wide enough to
 * hold all conversion input from 32-bit RGB to any output format.
 * The Linux kernel should avoid format conversion for anything
 * but XRGB8888 input data. Converting from other format can still
 * be acceptable in some cases.
 *
 * The return type is u32. It is wide enough to hold all conversion
 * output from XRGB8888. For output formats wider than 32 bit, a
 * return type of u64 would be acceptable.
 */

/*
 * Conversions from XRGB8888
 */

static inline u32 drm_pixel_xrgb8888_to_r8_bt601(u32 pix)
{
	u32 r = (pix & 0x00ff0000) >> 16;
	u32 g = (pix & 0x0000ff00) >> 8;
	u32 b =  pix & 0x000000ff;

	/* ITU-R BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
	return (77 * r + 150 * g + 29 * b) / 256;
}

static inline u32 drm_pixel_xrgb8888_to_rgb332(u32 pix)
{
	return ((pix & 0x00e00000) >> 16) |
	       ((pix & 0x0000e000) >> 11) |
	       ((pix & 0x000000c0) >> 6);
}

static inline u32 drm_pixel_xrgb8888_to_rgb565(u32 pix)
{
	return ((pix & 0x00f80000) >> 8) |
	       ((pix & 0x0000fc00) >> 5) |
	       ((pix & 0x000000f8) >> 3);
}

static inline u32 drm_pixel_xrgb8888_to_rgb565be(u32 pix)
{
	return swab16(drm_pixel_xrgb8888_to_rgb565(pix));
}

static inline u32 drm_pixel_xrgb8888_to_rgbx5551(u32 pix)
{
	return ((pix & 0x00f80000) >> 8) |
	       ((pix & 0x0000f800) >> 5) |
	       ((pix & 0x000000f8) >> 2);
}

static inline u32 drm_pixel_xrgb8888_to_rgba5551(u32 pix)
{
	return drm_pixel_xrgb8888_to_rgbx5551(pix) |
	       BIT(0); /* set alpha bit */
}

static inline u32 drm_pixel_xrgb8888_to_xrgb1555(u32 pix)
{
	return ((pix & 0x00f80000) >> 9) |
	       ((pix & 0x0000f800) >> 6) |
	       ((pix & 0x000000f8) >> 3);
}

static inline u32 drm_pixel_xrgb8888_to_argb1555(u32 pix)
{
	return BIT(15) | /* set alpha bit */
	       drm_pixel_xrgb8888_to_xrgb1555(pix);
}

Annotation

Implementation Notes