dm: video: Add damage tracking API

We are going to introduce image damage tracking to fasten up screen
refresh on large displays. This patch adds damage tracking for up to
one rectangle of the screen which is typically enough to hold blt or
text print updates. Callers into this API and a reduced dcache flush
code path will follow in later patches.

Signed-off-by: Alexander Graf <[email protected]>
Reported-by: Da Xue <[email protected]>
[Alper: Use xstart/yend, document new fields, return void from
        video_damage(), declare priv, drop headers, use IS_ENABLED()]
Co-developed-by: Alper Nebi Yasak <[email protected]>
Signed-off-by: Alper Nebi Yasak <[email protected]>
Link: https://lore.kernel.org/u-boot/[email protected]/
Reviewed-by: Simon Glass <[email protected]>

1 files changed, 38 insertions, 2 deletions

diff --git a/include/video.h b/include/video.h
index a1f7fd7e839..7eed112e00c 100644
--- a/include/video.h
+++ b/include/video.h
@@ -85,6 +85,11 @@ enum video_format {
  * @fb_size:	Frame buffer size
  * @copy_fb:	Copy of the frame buffer to keep up to date; see struct
  *		video_uc_plat
+ * @damage:	A bounding box of framebuffer regions updated since last sync
+ * @damage.xstart:	X start position in pixels from the left
+ * @damage.ystart:	Y start position in pixels from the top
+ * @damage.xend:	X end position in pixels from the left
+ * @damage.xend:	Y end position in pixels from the top
  * @line_length:	Length of each frame buffer line, in bytes. This can be
  *		set by the driver, but if not, the uclass will set it after
  *		probing
@@ -113,6 +118,12 @@ struct video_priv {
 	void *fb;
 	int fb_size;
 	void *copy_fb;
+	struct {
+		int xstart;
+		int ystart;
+		int xend;
+		int yend;
+	} damage;
 	int line_length;
 	u32 colour_fg;
 	u32 colour_bg;
@@ -259,8 +270,9 @@ int video_fill_part(struct udevice *dev, int xstart, int ystart, int xend,
  * @return: 0 on success, error code otherwise
  *
  * Some frame buffers are cached or have a secondary frame buffer. This
- * function syncs these up so that the current contents of the U-Boot frame
- * buffer are displayed to the user.
+ * function syncs the damaged parts of them up so that the current contents
+ * of the U-Boot frame buffer are displayed to the user. It clears the damage
+ * buffer.
  */
 int video_sync(struct udevice *vid, bool force);
 
@@ -380,6 +392,30 @@ static inline int video_sync_copy_all(struct udevice *dev)
 
 #endif
 
+#ifdef CONFIG_VIDEO_DAMAGE
+/**
+ * video_damage() - Notify the video subsystem about screen updates.
+ *
+ * @vid:	Device to sync
+ * @x:	        Upper left X coordinate of the damaged rectangle
+ * @y:	        Upper left Y coordinate of the damaged rectangle
+ * @width:	Width of the damaged rectangle
+ * @height:	Height of the damaged rectangle
+ *
+ * Some frame buffers are cached or have a secondary frame buffer. This
+ * function notifies the video subsystem about rectangles that were updated
+ * within the frame buffer. They may only get written to the screen on the
+ * next call to video_sync().
+ */
+void video_damage(struct udevice *vid, int x, int y, int width, int height);
+#else
+static inline void video_damage(struct udevice *vid, int x, int y, int width,
+				int height)
+{
+	return;
+}
+#endif /* CONFIG_VIDEO_DAMAGE */
+
 /**
  * video_is_active() - Test if one video device it active
  *