Hi Am 09.02.22 um 10:03 schrieb Javier Martinez Canillas:
Add support to convert XR24 and 8-bit grayscale to reversed monochrome for
drivers that control monochromatic panels, that only have 1 bit per pixel.
The drm_fb_gray8_to_mono_reversed() helper was based on the function that
does the same in the drivers/gpu/drm/tiny/repaper.c driver.
Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
Changes in v3:
- Also add a drm_fb_xrgb8888_to_mono_reversed() helper (Thomas Zimmermann)
- Split lines copy to drm_fb_gray8_to_mono_reversed_line() (Thomas Zimmermann)
- Handle case where the source buffer is not aligned to 8 (Thomas Zimmermann)
drivers/gpu/drm/drm_format_helper.c | 157 ++++++++++++++++++++++++++++
include/drm/drm_format_helper.h | 8 ++
2 files changed, 165 insertions(+)
diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index b981712623d3..19710342c0de 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -591,3 +591,160 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
return -EINVAL;
}
EXPORT_SYMBOL(drm_fb_blit_toio);
+
+static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels,
+ unsigned int start_offset, unsigned int end_offset)
+{
+ unsigned int xb, i;
+
+ for (xb = 0; xb < pixels; xb++) {
+ unsigned int start = 0, end = 8;
+ u8 byte = 0x00;
+
+ if (xb == 0 && start_offset)
+ start = start_offset;
+
+ if (xb == pixels - 1 && end_offset)
+ end = end_offset;
end_offset should be called end_len, because it is the number of bits in the final byte; but not the offset of the final bit.
+
+ for (i = start; i < end; i++) {
+ unsigned int x = xb * 8 + i;
+
+ byte >>= 1;
+ if (src[x] >> 7)
+ byte |= BIT(7);
+ }
+ *dst++ = byte;
+ }
+}
+
+/**
+ * drm_fb_gray8_to_mono_reversed - Convert grayscale to reversed monochrome
+ * @dst: reversed monochrome destination buffer
+ * @dst_pitch: Number of bytes between two consecutive scanlines within dst
+ * @src: 8-bit grayscale source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ *
+ * DRM doesn't have native monochrome or grayscale support.
+ * Such drivers can announce the commonly supported XR24 format to userspace
+ * and use drm_fb_xrgb8888_to_gray8() to convert to grayscale and then this
+ * helper function to convert to the native format.
+ */
+void drm_fb_gray8_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr,
+ const struct drm_framebuffer *fb,
+ const struct drm_rect *clip)
+{
+
+ unsigned int linepixels = drm_rect_width(clip);
+ unsigned int lines = drm_rect_height(clip);
+ unsigned int start_offset, end_offset;
+ unsigned int y;
+ const u8 *gray8 = vaddr;
+ u8 *mono = dst;
+
+ /*
+ * The reversed mono destination buffer contains 1 bit per pixel
+ * and destination scanlines have to be in multiple of 8 pixels.
+ */
+ if (!dst_pitch)
+ dst_pitch = DIV_ROUND_UP(linepixels, 8);
+
+ /*
+ * For damage handling, it is possible that only parts of the source
+ * buffer is copied and this could lead to start and end pixels that
+ * are not aligned to multiple of 8.
+ *
+ * Calculate if the start and end pixels are not aligned and set the
+ * offsets for the reversed mono line conversion function to adjust.
+ */
+ start_offset = clip->x1 % 8;
+ end_offset = clip->x2 % 8;
+
+ for (y = 0; y < lines; y++) {
+ drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch,
+ start_offset, end_offset);
+ gray8 += fb->pitches[0];
+ mono += dst_pitch;
+ }
+}
Do you really need that function. It's not exported and if it's not otherwise used, I'd just remove it. We don't keep unused interfaces around.
+
+/**
+ * drm_fb_xrgb8888_to_mono_reversed - Convert XRGB8888 to reversed monochrome
+ * @dst: reversed monochrome destination buffer
+ * @dst_pitch: Number of bytes between two consecutive scanlines within dst
+ * @src: XRGB8888 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ *
+ * DRM doesn't have native monochrome support.
+ * Such drivers can announce the commonly supported XR24 format to userspace
+ * and use this function to convert to the native format.
+ *
+ * This function uses drm_fb_xrgb8888_to_gray8() to convert to grayscale and
+ * then the result is converted from grayscale to reversed monohrome.
+ */
+void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr,
+ const struct drm_framebuffer *fb, const struct drm_rect *clip)
+{
+ unsigned int linepixels = drm_rect_width(clip);
+ unsigned int lines = clip->y2 - clip->y1;
+ unsigned int cpp = fb->format->cpp[0];
+ unsigned int len_src32 = linepixels * cpp;
+ unsigned int start_offset, end_offset;
+ unsigned int y;
+ u8 *mono = dst, *gray8;
+ u32 *src32;
+
+ if (WARN_ON(fb->format->format != DRM_FORMAT_XRGB8888))
+ return;
+
+ /*
+ * The reversed mono destination buffer contains 1 bit per pixel
+ * and destination scanlines have to be in multiple of 8 pixels.
+ */
+ if (!dst_pitch)
+ dst_pitch = DIV_ROUND_UP(linepixels, 8);
I'd do a warn_once if (dst_pitch % 8 != 0).
+ + /* + * The cma memory is write-combined so reads are uncached. + * Speed up by fetching one line at a time.
I once had a patchset that adds caching information to struct dma_buf_map (soon to be named struct iosys_map). Blitting helpers would be able to enable/disable this optimization as needed.
However, your driver doesn't use CMA. It's backed by SHMEM. Do you really want to keep that code in?
+ */ + src32 = kmalloc(len_src32, GFP_KERNEL); + if (!src32) + return; + + /* + * Copies are done line-by-line, allocate an intermediate + * buffer to copy the gray8 lines and then convert to mono. + */ + gray8 = kmalloc(linepixels, GFP_KERNEL); + if (!gray8) + goto free_src32;
If might be faster to allocate both buffers in one step and set the pointers into the allocated buffer.
+ + /* + * For damage handling, it is possible that only parts of the source + * buffer is copied and this could lead to start and end pixels that + * are not aligned to multiple of 8. + * + * Calculate if the start and end pixels are not aligned and set the + * offsets for the reversed mono line conversion function to adjust. + */ + start_offset = clip->x1 % 8; + end_offset = clip->x2 % 8;
end_len, again. If you have 1 single bit set in the final byte, the offset is 0, but the length is 1. Best regards Thomas
+ + vaddr += clip_offset(clip, fb->pitches[0], cpp); + for (y = 0; y < lines; y++) { + src32 = memcpy(src32, vaddr, len_src32); + drm_fb_xrgb8888_to_gray8_line(gray8, src32, linepixels); + drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch, + start_offset, end_offset); + vaddr += fb->pitches[0]; + mono += dst_pitch; + } + + kfree(gray8); +free_src32: + kfree(src32); +} +EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono_reversed); diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index b30ed5de0a33..6638da9e9774 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -43,4 +43,12 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for const void *vmap, const struct drm_framebuffer *fb, const struct drm_rect *rect);+void drm_fb_gray8_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *src,+ const struct drm_framebuffer *fb, + const struct drm_rect *clip); + +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *src, + const struct drm_framebuffer *fb, + const struct drm_rect *clip); + #endif /* __LINUX_DRM_FORMAT_HELPER_H */
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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