drm/format-helper: Rework XRGB8888-to-RGBG565 conversion

Update XRGB8888-to-RGB565 conversion to support struct iosys_map
and convert all users. Although these are single-plane color formats,
the new interface supports multi-plane formats for consistency with
drm_fb_blit().

v2:
	* update new Kunit tests
	* update documentation (Sam)
	* add TODO on vaddr location (Sam)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220808125406.20752-7-tzimmermann@suse.de

1 files changed, 35 insertions, 38 deletions

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 248fd87f0a36..a77291d2f9b9 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -357,53 +357,51 @@ static void drm_fb_xrgb8888_to_rgb565_swab_line(void *dbuf, const void *sbuf,
 
 /**
  * drm_fb_xrgb8888_to_rgb565 - Convert XRGB8888 to RGB565 clip buffer
- * @dst: RGB565 destination buffer
- * @dst_pitch: Number of bytes between two consecutive scanlines within dst
- * @vaddr: XRGB8888 source buffer
+ * @dst: Array of RGB565 destination buffers
+ * @dst_pitch: Array of numbers of bytes between the start of two consecutive scanlines
+ *             within @dst; can be NULL if scanlines are stored next to each other.
+ * @vmap: Array of XRGB8888 source buffer
  * @fb: DRM framebuffer
  * @clip: Clip rectangle area to copy
  * @swab: Swap bytes
  *
- * Drivers can use this function for RGB565 devices that don't natively
- * support XRGB8888.
+ * This function copies parts of a framebuffer to display memory and converts the
+ * color format during the process. Destination and framebuffer formats must match. The
+ * parameters @dst, @dst_pitch and @vmap refer to arrays. Each array must have at
+ * least as many entries as there are planes in @fb's format. Each entry stores the
+ * value for the format's respective color plane at the same index.
+ *
+ * This function does not apply clipping on @dst (i.e. the destination is at the
+ * top-left corner).
+ *
+ * Drivers can use this function for RGB565 devices that don't support XRGB8888 natively.
  */
-void drm_fb_xrgb8888_to_rgb565(void *dst, unsigned int dst_pitch, const void *vaddr,
-			       const struct drm_framebuffer *fb, const struct drm_rect *clip,
-			       bool swab)
+void drm_fb_xrgb8888_to_rgb565(struct iosys_map *dst, const unsigned int *dst_pitch,
+			       const struct iosys_map *vmap, const struct drm_framebuffer *fb,
+			       const struct drm_rect *clip, bool swab)
 {
+	static const unsigned int default_dst_pitch[DRM_FORMAT_MAX_PLANES] = {
+		0, 0, 0, 0
+	};
+	void (*xfrm_line)(void *dbuf, const void *sbuf, unsigned int npixels);
+
 	if (swab)
-		drm_fb_xfrm(dst, dst_pitch, 2, vaddr, fb, clip, false,
-			    drm_fb_xrgb8888_to_rgb565_swab_line);
+		xfrm_line = drm_fb_xrgb8888_to_rgb565_swab_line;
 	else
-		drm_fb_xfrm(dst, dst_pitch, 2, vaddr, fb, clip, false,
-			    drm_fb_xrgb8888_to_rgb565_line);
-}
-EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb565);
+		xfrm_line = drm_fb_xrgb8888_to_rgb565_line;
 
-/**
- * drm_fb_xrgb8888_to_rgb565_toio - Convert XRGB8888 to RGB565 clip buffer
- * @dst: RGB565 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
- * @swab: Swap bytes
- *
- * Drivers can use this function for RGB565 devices that don't natively
- * support XRGB8888.
- */
-void drm_fb_xrgb8888_to_rgb565_toio(void __iomem *dst, unsigned int dst_pitch,
-				    const void *vaddr, const struct drm_framebuffer *fb,
-				    const struct drm_rect *clip, bool swab)
-{
-	if (swab)
-		drm_fb_xfrm_toio(dst, dst_pitch, 2, vaddr, fb, clip, false,
-				 drm_fb_xrgb8888_to_rgb565_swab_line);
+	if (!dst_pitch)
+		dst_pitch = default_dst_pitch;
+
+	/* TODO: handle vmap in I/O memory here */
+	if (dst[0].is_iomem)
+		drm_fb_xfrm_toio(dst[0].vaddr_iomem, dst_pitch[0], 2, vmap[0].vaddr, fb, clip,
+				 false, xfrm_line);
 	else
-		drm_fb_xfrm_toio(dst, dst_pitch, 2, vaddr, fb, clip, false,
-				 drm_fb_xrgb8888_to_rgb565_line);
+		drm_fb_xfrm(dst[0].vaddr, dst_pitch[0], 2, vmap[0].vaddr, fb, clip,
+			    false, xfrm_line);
 }
-EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb565_toio);
+EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb565);
 
 static void drm_fb_xrgb8888_to_rgb888_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
@@ -635,8 +633,7 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 
 	} else if (dst_format == DRM_FORMAT_RGB565) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_xrgb8888_to_rgb565_toio(dst[0].vaddr_iomem, dst_pitch[0],
-						       vmap[0].vaddr, fb, clip, false);
+			drm_fb_xrgb8888_to_rgb565(dst, dst_pitch, vmap, fb, clip, false);
 			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_RGB888) {