drm/format-helper: Rework RGB565-to-XRGB8888 conversion

Update RGB565-to-XRGB8888 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:
	* add TODO on vaddr location (Sam)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220808125406.20752-9-tzimmermann@suse.de

drivers/gpu/drm/drm_format_helper.c

@@ -478,12 +478,25 @@ static void drm_fb_rgb565_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigne
 	}
 }
 
-static void drm_fb_rgb565_to_xrgb8888_toio(void __iomem *dst, unsigned int dst_pitch,
-					   const void *vaddr, const struct drm_framebuffer *fb,
+static void drm_fb_rgb565_to_xrgb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
+				      const struct iosys_map *vmap,
+				      const struct drm_framebuffer *fb,
 				      const struct drm_rect *clip)
 {
-	drm_fb_xfrm_toio(dst, dst_pitch, 4, vaddr, fb, clip, false,
-			 drm_fb_rgb565_to_xrgb8888_line);
+	static const unsigned int default_dst_pitch[DRM_FORMAT_MAX_PLANES] = {
+		0, 0, 0, 0
+	};
+
+	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], 4, vmap[0].vaddr, fb,
+				 clip, false, drm_fb_rgb565_to_xrgb8888_line);
+	else
+		drm_fb_xfrm(dst[0].vaddr, dst_pitch[0], 4, vmap[0].vaddr, 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)
@@ -651,8 +664,7 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 						       vmap[0].vaddr, fb, clip);
 			return 0;
 		} else if (fb_format == DRM_FORMAT_RGB565) {
-			drm_fb_rgb565_to_xrgb8888_toio(dst[0].vaddr_iomem, dst_pitch[0],
-						       vmap[0].vaddr, fb, clip);
+			drm_fb_rgb565_to_xrgb8888(dst, dst_pitch, vmap, fb, clip);
 			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_XRGB2101010) {