drm: Add a new plane property to send damage during plane update

FB_DAMAGE_CLIPS is an optional plane property to mark damaged regions
on the plane in framebuffer coordinates of the framebuffer attached to
the plane.

The layout of blob data is simply an array of "struct drm_mode_rect".
Unlike plane src coordinates, damage clips are not in 16.16 fixed point.
As plane src in framebuffer cannot be negative so are damage clips. In
damage clip, x1/y1 are inclusive and x2/y2 are exclusive.

This patch also exports the kernel internal drm_rect to userspace as
drm_mode_rect. This is because "struct drm_clip_rect" is not sufficient
to represent damage for current plane size.

Driver which are interested in enabling FB_DAMAGE_CLIPS property for a
plane should enable this property using drm_plane_enable_damage_clips.

v2:
- Input validation on damage clips against framebuffer size.
- Doc update, other minor changes.

Signed-off-by: Lukasz Spintzyk <lukasz.spintzyk@displaylink.com>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 3701f56c3362..87153ecb5f1f 100644
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -173,6 +173,16 @@ struct drm_plane_state {
 	 */
 	enum drm_color_range color_range;
 
+	/**
+	 * @fb_damage_clips:
+	 *
+	 * Blob representing damage (area in plane framebuffer that changed
+	 * since last plane update) as an array of &drm_mode_rect in framebuffer
+	 * coodinates of the attached framebuffer. Note that unlike plane src,
+	 * damage clips are not in 16.16 fixed point.
+	 */
+	struct drm_property_blob *fb_damage_clips;
+
 	/** @src: clipped source coordinates of the plane (in 16.16) */
 	/** @dst: clipped destination coordinates of the plane */
 	struct drm_rect src, dst;
@@ -800,5 +810,35 @@ static inline struct drm_plane *drm_plane_find(struct drm_device *dev,
 
 bool drm_any_plane_has_format(struct drm_device *dev,
 			      u32 format, u64 modifier);
+/**
+ * drm_plane_get_damage_clips_count - Returns damage clips count.
+ * @state: Plane state.
+ *
+ * Simple helper to get the number of &drm_mode_rect clips set by user-space
+ * during plane update.
+ *
+ * Return: Number of clips in plane fb_damage_clips blob property.
+ */
+static inline unsigned int
+drm_plane_get_damage_clips_count(const struct drm_plane_state *state)
+{
+	return (state && state->fb_damage_clips) ?
+		state->fb_damage_clips->length/sizeof(struct drm_mode_rect) : 0;
+}
+
+/**
+ * drm_plane_get_damage_clips - Returns damage clips.
+ * @state: Plane state.
+ *
+ * Note that this function returns uapi type &drm_mode_rect.
+ *
+ * Return: Damage clips in plane fb_damage_clips blob property.
+ */
+static inline struct drm_mode_rect *
+drm_plane_get_damage_clips(const struct drm_plane_state *state)
+{
+	return (struct drm_mode_rect *)((state && state->fb_damage_clips) ?
+					state->fb_damage_clips->data : NULL);
+}
 
 #endif