drm/format-helper: Remove unnecessary conversion helpers

Drivers only emulate XRGB8888 framebuffers. Remove all conversion
helpers that do not use XRGB8888 as their source format. Also remove
some special cases for alpha formats in the blit helper.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-14-tzimmermann@suse.de

drivers/gpu/drm/drm_format_helper.c

@@ -649,65 +649,6 @@ void drm_fb_xrgb8888_to_argb8888(struct iosys_map *dst, const unsigned int *dst_
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_argb8888);
 
-static void drm_fb_rgb565_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
-{
-	__le32 *dbuf32 = dbuf;
-	const __le16 *sbuf16 = sbuf;
-	unsigned int x;
-
-	for (x = 0; x < pixels; x++) {
-		u16 val16 = le16_to_cpu(sbuf16[x]);
-		u32 val32 = ((val16 & 0xf800) << 8) |
-			    ((val16 & 0x07e0) << 5) |
-			    ((val16 & 0x001f) << 3);
-		val32 = 0xff000000 | val32 |
-			((val32 >> 3) & 0x00070007) |
-			((val32 >> 2) & 0x00000300);
-		dbuf32[x] = cpu_to_le32(val32);
-	}
-}
-
-static void drm_fb_rgb565_to_xrgb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
-				      const struct iosys_map *src,
-				      const struct drm_framebuffer *fb,
-				      const struct drm_rect *clip)
-{
-	static const u8 dst_pixsize[DRM_FORMAT_MAX_PLANES] = {
-		4,
-	};
-
-	drm_fb_xfrm(dst, dst_pitch, dst_pixsize, src, fb, clip, false,
-		    drm_fb_rgb565_to_xrgb8888_line);
-}
-
-static void drm_fb_rgb888_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
-{
-	__le32 *dbuf32 = dbuf;
-	const u8 *sbuf8 = sbuf;
-	unsigned int x;
-
-	for (x = 0; x < pixels; x++) {
-		u8 r = *sbuf8++;
-		u8 g = *sbuf8++;
-		u8 b = *sbuf8++;
-		u32 pix = 0xff000000 | (r << 16) | (g << 8) | b;
-		dbuf32[x] = cpu_to_le32(pix);
-	}
-}
-
-static void drm_fb_rgb888_to_xrgb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
-				      const struct iosys_map *src,
-				      const struct drm_framebuffer *fb,
-				      const struct drm_rect *clip)
-{
-	static const u8 dst_pixsize[DRM_FORMAT_MAX_PLANES] = {
-		4,
-	};
-
-	drm_fb_xfrm(dst, dst_pitch, dst_pixsize, src, fb, clip, false,
-		    drm_fb_rgb888_to_xrgb8888_line);
-}
-
 static void drm_fb_xrgb8888_to_xrgb2101010_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
 	__le32 *dbuf32 = dbuf;
@@ -899,12 +840,6 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 {
 	uint32_t fb_format = fb->format->format;
 
-	/* treat alpha channel like filler bits */
-	if (fb_format == DRM_FORMAT_ARGB8888)
-		fb_format = DRM_FORMAT_XRGB8888;
-	if (fb_format == DRM_FORMAT_ARGB2101010)
-		fb_format = DRM_FORMAT_XRGB2101010;
-
 	if (fb_format == dst_format) {
 		drm_fb_memcpy(dst, dst_pitch, src, fb, clip);
 		return 0;
@@ -943,16 +878,6 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 			drm_fb_swab(dst, dst_pitch, src, fb, clip, false);
 			return 0;
 		}
-	} else if (fb_format == DRM_FORMAT_RGB888) {
-		if (dst_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_rgb888_to_xrgb8888(dst, dst_pitch, src, fb, clip);
-			return 0;
-		}
-	} else if (fb_format == DRM_FORMAT_RGB565) {
-		if (dst_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_rgb565_to_xrgb8888(dst, dst_pitch, src, fb, clip);
-			return 0;
-		}
 	}
 
 	drm_warn_once(fb->dev, "No conversion helper from %p4cc to %p4cc found.\n",