[PATCH v5 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line()

Javier Martinez Canillas
2022-02-11T14:34:12Z

Pull the per-line conversion logic into a separate helper function.

This will allow to do line-by-line conversion in other helpers that
convert to a gray8 format.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---

Changes in v5:
- Add Thomas Zimmermann's Reviewed-by to patch #1.

Changes in v3:
- Add a drm_fb_xrgb8888_to_gray8_line() helper function (Thomas Zimmermann)

drivers/gpu/drm/drm_format_helper.c | 31 ++++++++++++++++++-----------
1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 0f28dd2bdd72..b981712623d3 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -464,6 +464,21 @@ void drm_fb_xrgb8888_to_xrgb2101010_toio(void __iomem *dst,
}
EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_toio);

+static void drm_fb_xrgb8888_to_gray8_line(u8 *dst, const u32 *src, unsigned int pixels)
+{
+ unsigned int x;
+
+ for (x = 0; x < pixels; x++) {
+ u8 r = (*src & 0x00ff0000) >> 16;
+ u8 g = (*src & 0x0000ff00) >> 8;
+ u8 b = *src & 0x000000ff;
+
+ /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
+ *dst++ = (3 * r + 6 * g + b) / 10;
+ src++;
+ }
+}
+
/**
* drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
* @dst: 8-bit grayscale destination buffer
@@ -484,8 +499,9 @@ EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_toio);
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)
{
- unsigned int len = (clip->x2 - clip->x1) * sizeof(u32);
- unsigned int x, y;
+ unsigned int linepixels = clip->x2 - clip->x1;
+ unsigned int len = linepixels * sizeof(u32);
+ unsigned int y;
void *buf;
u8 *dst8;
u32 *src32;
@@ -508,16 +524,7 @@ void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vad
for (y = clip->y1; y < clip->y2; y++) {
dst8 = dst;
src32 = memcpy(buf, vaddr, len);
- for (x = clip->x1; x < clip->x2; x++) {
- u8 r = (*src32 & 0x00ff0000) >> 16;
- u8 g = (*src32 & 0x0000ff00) >> 8;
- u8 b = *src32 & 0x000000ff;
-
- /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
- *dst8++ = (3 * r + 6 * g + b) / 10;
- src32++;
- }
-
+ drm_fb_xrgb8888_to_gray8_line(dst8, src32, linepixels);
vaddr += fb->pitches[0];
dst += dst_pitch;
}
--
2.34.1