Commit cee0b7cb authored by Noralf Trønnes's avatar Noralf Trønnes
Browse files

drm/format-helper: Add drm_fb_xrgb8888_to_rgb332() 



Add XRGB8888 emulation support for devices that can only do RGB332.

v2:
- Support Big Endian (Daniel)

Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210929191201.34456-3-noralf@tronnes.org
parent a0b1d355

drivers/gpu/drm/drm_format_helper.c

+50 −0
Original line number Diff line number Diff line
@@ -135,6 +135,56 @@ void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb, 
}

EXPORT_SYMBOL(drm_fb_swab);



static void drm_fb_xrgb8888_to_rgb332_line(u8 *dbuf, __le32 *sbuf, unsigned int pixels)

{

	unsigned int x;

	u32 pix;



	for (x = 0; x < pixels; x++) {

		pix = le32_to_cpu(sbuf[x]);

		dbuf[x] = ((pix & 0x00e00000) >> 16) |

			  ((pix & 0x0000e000) >> 11) |

			  ((pix & 0x000000c0) >> 6);

	}

}



/**

 * drm_fb_xrgb8888_to_rgb332 - Convert XRGB8888 to RGB332 clip buffer

 * @dst: RGB332 destination buffer

 * @src: XRGB8888 source buffer

 * @fb: DRM framebuffer

 * @clip: Clip rectangle area to copy

 *

 * Drivers can use this function for RGB332 devices that don't natively support XRGB8888.

 *

 * This function does not apply clipping on dst, i.e. the destination is a small buffer

 * containing the clip rect only.

 */

void drm_fb_xrgb8888_to_rgb332(void *dst, void *src, struct drm_framebuffer *fb,

			       struct drm_rect *clip)

{

	size_t width = drm_rect_width(clip);

	size_t src_len = width * sizeof(u32);

	unsigned int y;

	void *sbuf;



	/* Use a buffer to speed up access on buffers with uncached read mapping (i.e. WC) */

	sbuf = kmalloc(src_len, GFP_KERNEL);

	if (!sbuf)

		return;



	src += clip_offset(clip, fb->pitches[0], sizeof(u32));

	for (y = 0; y < drm_rect_height(clip); y++) {

		memcpy(sbuf, src, src_len);

		drm_fb_xrgb8888_to_rgb332_line(dst, sbuf, width);

		src += fb->pitches[0];

		dst += width;

	}



	kfree(sbuf);

}

EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb332);



static void drm_fb_xrgb8888_to_rgb565_line(u16 *dbuf, u32 *sbuf,

					   unsigned int pixels,

					   bool swab)

include/drm/drm_format_helper.h

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ void drm_fb_memcpy_dstclip(void __iomem *dst, unsigned int dst_pitch, void *vadd 
			   struct drm_rect *clip);

void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb,

		 struct drm_rect *clip, bool cached);

void drm_fb_xrgb8888_to_rgb332(void *dst, void *vaddr, struct drm_framebuffer *fb,

			       struct drm_rect *clip);

void drm_fb_xrgb8888_to_rgb565(void *dst, void *vaddr,

			       struct drm_framebuffer *fb,

			       struct drm_rect *clip, bool swab);