Den 17.08.2021 15.56, skrev Daniel Vetter:
On Tue, Aug 17, 2021 at 02:29:12PM +0200, Noralf Trønnes wrote:
Add XRGB8888 emulation support for devices that can only do RGB332.
Cc: Thomas Zimmermann tzimmermann@suse.de Signed-off-by: Noralf Trønnes noralf@tronnes.org
drivers/gpu/drm/drm_format_helper.c | 47 +++++++++++++++++++++++++++++ include/drm/drm_format_helper.h | 2 ++ 2 files changed, 49 insertions(+)
diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 5231104b1498..53b426da7467 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -135,6 +135,53 @@ 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, u32 *sbuf, unsigned int pixels) +{
- unsigned int x;
- for (x = 0; x < pixels; x++)
dbuf[x] = ((sbuf[x] & 0x00e00000) >> 16) |I think for 2/3 bits correct rounding would be useful, not just masking. i.e. before you shift add 0x00100000 here, and similar below.
Math isn't my strongest side and my brain failed to turn this into code.
Also I just realized we've totally ignored endianess on these, which is not great, because strictly speaking all the drm_fourcc codes should be little endian. But I'm also not sure that's worth fixing ...
Is it as simple as using le32_to_cpu()?
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); } }
Noralf.
Either way, lgtm:
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
((sbuf[x] & 0x0000e000) >> 11) |((sbuf[x] & 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) diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index 4e0258a61311..d0809aff5cf8 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -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); -- 2.32.0