video: Only dcache flush damaged lines

Now that we have a damage area tells us which parts of the frame buffer
actually need updating, let's only dcache flush those on video_sync()
calls. With this optimization in place, frame buffer updates - especially
on large screen such as 4k displays - speed up significantly.

Signed-off-by: Alexander Graf <agraf@csgraf.de>
Reported-by: Da Xue <da@libre.computer>
[Alper: Use damage.xstart/yend, IS_ENABLED()]
Co-developed-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Link: https://lore.kernel.org/u-boot/20230821135111.3558478-11-alpernebiyasak@gmail.com/

diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
index 3933aeb..8fb3b22 100644 (file)
--- a/drivers/video/video-uclass.c
+++ b/drivers/video/video-uclass.c
@@ -401,6 +401,40 @@ void video_damage(struct udevice *vid, int x, int y, int width, int height)
 }
 #endif
 
+#if defined(CONFIG_ARM) && !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
+static void video_flush_dcache(struct udevice *vid, bool use_copy)
+{
+       struct video_priv *priv = dev_get_uclass_priv(vid);
+       ulong fb = use_copy ? (ulong)priv->copy_fb : (ulong)priv->fb;
+
+       if (!priv->flush_dcache)
+               return;
+
+       if (!IS_ENABLED(CONFIG_VIDEO_DAMAGE)) {
+               flush_dcache_range(fb, ALIGN(fb + priv->fb_size,
+                                            CONFIG_SYS_CACHELINE_SIZE));
+
+               return;
+       }
+
+       if (priv->damage.xend && priv->damage.yend) {
+               int lstart = priv->damage.xstart * VNBYTES(priv->bpix);
+               int lend = priv->damage.xend * VNBYTES(priv->bpix);
+               int y;
+
+               for (y = priv->damage.ystart; y < priv->damage.yend; y++) {
+                       ulong start = fb + (y * priv->line_length) + lstart;
+                       ulong end = start + lend - lstart;
+
+                       start = ALIGN_DOWN(start, CONFIG_SYS_CACHELINE_SIZE);
+                       end = ALIGN(end, CONFIG_SYS_CACHELINE_SIZE);
+
+                       flush_dcache_range(start, end);
+               }
+       }
+}
+#endif
+
 /* Flush video activity to the caches */
 int video_sync(struct udevice *vid, bool force)
 {
@@ -424,11 +458,10 @@ int video_sync(struct udevice *vid, bool force)
         * out whether it exists? For now, ARM is safe.
         */
 #if defined(CONFIG_ARM) && !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
-       if (priv->flush_dcache) {
-               flush_dcache_range((ulong)priv->fb,
-                                  ALIGN((ulong)priv->fb + priv->fb_size,
-                                        CONFIG_SYS_CACHELINE_SIZE));
-       }
+       video_flush_dcache(vid, false);
+
+       if (IS_ENABLED(CONFIG_VIDEO_COPY))
+               video_flush_dcache(vid, true);
 #elif defined(CONFIG_VIDEO_SANDBOX_SDL)
        sandbox_sdl_sync(priv->fb);
 #endif