[PATCH v2 5/6] drm: add drm_fb_xrgb8888_to_rgb888() function to drm_fb_helper.c

[Gerd Hoffmann <kraxel@redhat.com>]

Like drm_fb_xrgb8888_to_rgb565() but converts to 24bpp (DRM_FORMAT_RGB888).

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 include/drm/drm_fb_helper.h     |  4 +++
 drivers/gpu/drm/drm_fb_helper.c | 49 +++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 1406057e1a93..a6e56fcd948e 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -648,5 +648,9 @@ void drm_fb_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
 			       struct drm_framebuffer *fb,
 			       struct drm_rect *clip,
 			       bool swap, bool dstclip);
+void drm_fb_xrgb8888_to_rgb888(u8 *dst, void *vaddr,
+			       struct drm_framebuffer *fb,
+			       struct drm_rect *clip,
+			       bool dstclip);
 
 #endif
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 2c9286702c3f..6ef0ad4f40b1 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -3431,3 +3431,52 @@ void drm_fb_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
 	kfree(buf);
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb565);
+
+/**
+ * drm_fb_xrgb8888_to_rgb888 - Convert XRGB8888 to RGB888 clip buffer
+ * @dst: RGB565 destination buffer
+ * @vaddr: XRGB8888 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ * @dstclip: Clip destination too.
+ *
+ * Drivers can use this function for RGB888 devices that don't natively
+ * support XRGB8888.
+ */
+void drm_fb_xrgb8888_to_rgb888(u8 *dst, void *vaddr,
+			       struct drm_framebuffer *fb,
+			       struct drm_rect *clip,
+			       bool dstclip)
+{
+	size_t len = (clip->x2 - clip->x1) * sizeof(u32);
+	unsigned int x, y;
+	u32 *src, *buf;
+	u8 red, green, blue;
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	if (dstclip)
+		dst += (clip->y1 * fb->width + clip->x1) * 3;
+	for (y = clip->y1; y < clip->y2; y++) {
+		src = vaddr + (y * fb->pitches[0]);
+		src += clip->x1;
+		memcpy(buf, src, len);
+		src = buf;
+		for (x = clip->x1; x < clip->x2; x++) {
+			red   = (*src & 0x00FF0000) >> 16;
+			green = (*src & 0x0000FF00) >>  8;
+			blue  = (*src & 0x000000FF) >>  0;
+			src++;
+			*dst++ = blue;
+			*dst++ = green;
+			*dst++ = red;
+		}
+		if (dstclip)
+			dst += (fb->width - (clip->x2 - clip->x1)) * 3;
+	}
+
+	kfree(buf);
+}
+EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888);
-- 
2.18.1