Re: [PATCH v2 2/3] drm/format-helper: Add drm_fb_xrgb8888_to_xrgb2101010_toio()

Hi

Am 07.12.21 um 08:29 schrieb Hector Martin:

Add XRGB8888 emulation support for devices that can only do XRGB2101010.

This is chiefly useful for simpledrm on Apple devices where the bootloader-provided framebuffer is 10-bit.

Signed-off-by: Hector Martin marcan@marcan.st

drivers/gpu/drm/drm_format_helper.c | 62 +++++++++++++++++++++++++++++ include/drm/drm_format_helper.h | 3 ++ 2 files changed, 65 insertions(+)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index dbe3e830096e..edd611d3ab6a 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -409,6 +409,59 @@ void drm_fb_xrgb8888_to_rgb888_toio(void __iomem *dst, unsigned int dst_pitch, } EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888_toio);

+static void drm_fb_xrgb8888_to_xrgb2101010_line(u32 *dbuf, const u32 *sbuf,

• 				unsigned int pixels)
  

+{

• unsigned int x;
• for (x = 0; x < pixels; x++) {

• *dbuf++ = ((sbuf[x] & 0x000000FF) << 2) |
  

• 	  ((sbuf[x] & 0x0000FF00) << 4) |
  

• 	  ((sbuf[x] & 0x00FF0000) << 6);
  

This isn't quite right. The lowest two destination bits in each component will always be zero. You have to do the shifting as above and for each component the two highest source bits have to be OR'ed into the two lowest destination bits. For example the source bits in a component are numbered 7 to 0

| 7 6 5 4 3 2 1 0 |

then the destination bits should be

| 7 6 5 4 3 2 1 0 7 6 |

Best regards Thomas

• }

+}

+/**

• • drm_fb_xrgb8888_to_xrgb2101010_toio - Convert XRGB8888 to XRGB2101010 clip
• • buffer
• • @dst: XRGB2101010 destination buffer (iomem)
• • @dst_pitch: Number of bytes between two consecutive scanlines within dst
• • @vaddr: XRGB8888 source buffer
• • @fb: DRM framebuffer
• • @clip: Clip rectangle area to copy
• • Drivers can use this function for XRGB2101010 devices that don't natively
• • support XRGB8888.
• */

+void drm_fb_xrgb8888_to_xrgb2101010_toio(void __iomem *dst,

• 			 unsigned int dst_pitch, const void *vaddr,
  

• 			 const struct drm_framebuffer *fb,
  

• 			 const struct drm_rect *clip)
  

+{

• size_t linepixels = clip->x2 - clip->x1;
• size_t dst_len = linepixels * sizeof(u32);
• unsigned y, lines = clip->y2 - clip->y1;
• void *dbuf;
• if (!dst_pitch)

• dst_pitch = dst_len;
  

• dbuf = kmalloc(dst_len, GFP_KERNEL);
• if (!dbuf)

• return;
  

• vaddr += clip_offset(clip, fb->pitches[0], sizeof(u32));
• for (y = 0; y < lines; y++) {

• drm_fb_xrgb8888_to_xrgb2101010_line(dbuf, vaddr, linepixels);
  

• memcpy_toio(dst, dbuf, dst_len);
  

• vaddr += fb->pitches[0];
  

• dst += dst_pitch;
  

• }
• kfree(dbuf);

+} +EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_toio);

• /**
  • drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
  • @dst: 8-bit grayscale destination buffer

@@ -500,6 +553,10 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for fb_format = DRM_FORMAT_XRGB8888; if (dst_format == DRM_FORMAT_ARGB8888) dst_format = DRM_FORMAT_XRGB8888;

• if (fb_format == DRM_FORMAT_ARGB2101010)

• fb_format = DRM_FORMAT_XRGB2101010;
  

• if (dst_format == DRM_FORMAT_ARGB2101010)

• dst_format = DRM_FORMAT_XRGB2101010;
  
  

  if (dst_format == fb_format) { drm_fb_memcpy_toio(dst, dst_pitch, vmap, fb, clip);

@@ -515,6 +572,11 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for drm_fb_xrgb8888_to_rgb888_toio(dst, dst_pitch, vmap, fb, clip); return 0; }

• } else if (dst_format == DRM_FORMAT_XRGB2101010) {

• if (fb_format == DRM_FORMAT_XRGB8888) {
  

• 	drm_fb_xrgb8888_to_xrgb2101010_toio(dst, dst_pitch, vmap, fb, clip);
  

• 	return 0;
  

• }
  

  }

  return -EINVAL;

diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index 97e4c3223af3..b30ed5de0a33 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -33,6 +33,9 @@ void drm_fb_xrgb8888_to_rgb888(void *dst, unsigned int dst_pitch, const void *sr void drm_fb_xrgb8888_to_rgb888_toio(void __iomem *dst, unsigned int dst_pitch, const void *vaddr, const struct drm_framebuffer *fb, const struct drm_rect *clip); +void drm_fb_xrgb8888_to_xrgb2101010_toio(void __iomem *dst, unsigned int dst_pitch,

• 			 const void *vaddr, const struct drm_framebuffer *fb,
  

• 			 const struct drm_rect *clip);
  

  void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vaddr, const struct drm_framebuffer *fb, const struct drm_rect *clip);