Commit e5bd7e3e authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Sam Ravnborg
Browse files

drm/fourcc: Add DRM_FORMAT_C[124] 



Introduce fourcc codes for color-indexed frame buffer formats with two,
four, and sixteen colors, and provide a mapping from bits per pixel and
depth to fourcc codes.

As the number of bits per pixel is less than eight, these rely on proper
block handling for the calculation of bits per pixel and pitch.

The fill order (the order in which multiple pixels are packed in a byte)
is the same order as used for indexed-color (2, 4, and 16 colors) images
in the PNG specification, Version 1.2.
This order is also the recommended and default order (FillOrder = 1) for
palette-color (16 colors) images in the TIFF 6.0 Specification, and is
also used for 16-color Linux frame buffer logos.

Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: default avatarPekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/3d88ca7ad32ff3ff3469c10f0b36c312ea233a33.1657294931.git.geert@linux-m68k.org
parent 4c59b080

drivers/gpu/drm/drm_fourcc.c

+21 −0
Original line number Diff line number Diff line
@@ -43,6 +43,21 @@ uint32_t drm_mode_legacy_fb_format(uint32_t bpp, uint32_t depth) 
	uint32_t fmt = DRM_FORMAT_INVALID;



	switch (bpp) {

	case 1:

		if (depth == 1)

			fmt = DRM_FORMAT_C1;

		break;



	case 2:

		if (depth == 2)

			fmt = DRM_FORMAT_C2;

		break;



	case 4:

		if (depth == 4)

			fmt = DRM_FORMAT_C4;

		break;



	case 8:

		if (depth == 8)

			fmt = DRM_FORMAT_C8;
@@ -132,6 +147,12 @@ EXPORT_SYMBOL(drm_driver_legacy_fb_format); 
const struct drm_format_info *__drm_format_info(u32 format)

{

	static const struct drm_format_info formats[] = {

		{ .format = DRM_FORMAT_C1,		.depth = 1,  .num_planes = 1,

		  .char_per_block = { 1, }, .block_w = { 8, }, .block_h = { 1, }, .hsub = 1, .vsub = 1, .is_color_indexed = true },

		{ .format = DRM_FORMAT_C2,		.depth = 2,  .num_planes = 1,

		  .char_per_block = { 1, }, .block_w = { 4, }, .block_h = { 1, }, .hsub = 1, .vsub = 1, .is_color_indexed = true },

		{ .format = DRM_FORMAT_C4,		.depth = 4,  .num_planes = 1,

		  .char_per_block = { 1, }, .block_w = { 2, }, .block_h = { 1, }, .hsub = 1, .vsub = 1, .is_color_indexed = true },

		{ .format = DRM_FORMAT_C8,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1, .is_color_indexed = true },

		{ .format = DRM_FORMAT_R8,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 },

		{ .format = DRM_FORMAT_R10,		.depth = 10, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },

include/uapi/drm/drm_fourcc.h

+3 −0
Original line number Diff line number Diff line
@@ -99,6 +99,9 @@ extern "C" { 
#define DRM_FORMAT_INVALID	0



/* color index */

#define DRM_FORMAT_C1		fourcc_code('C', '1', ' ', ' ') /* [7:0] C0:C1:C2:C3:C4:C5:C6:C7 1:1:1:1:1:1:1:1 eight pixels/byte */

#define DRM_FORMAT_C2		fourcc_code('C', '2', ' ', ' ') /* [7:0] C0:C1:C2:C3 2:2:2:2 four pixels/byte */

#define DRM_FORMAT_C4		fourcc_code('C', '4', ' ', ' ') /* [7:0] C0:C1 4:4 two pixels/byte */

#define DRM_FORMAT_C8		fourcc_code('C', '8', ' ', ' ') /* [7:0] C */



/* 8 bpp Red */