[PATCH] drm: add a drm_atomic_helper_plane_check_update

[John Hunter]

From: Zhao Junwang <zhjwpku at gmail.com>

Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Zhao Junwang <zhjwpku at gmail.com>
---
 drivers/gpu/drm/drm_atomic_helper.c |   55 +++++++++++++++++++++++++++++++++++
 include/drm/drm_atomic_helper.h     |    7 +++++
 2 files changed, 62 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 536ae4d..3d94ff8 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1336,6 +1336,61 @@ void drm_atomic_helper_swap_state(struct drm_device *dev,
 EXPORT_SYMBOL(drm_atomic_helper_swap_state);
 
 /**
+ * drm_atomic_helper_plane_check_update
+ * @plane: plane object to update
+ * @state: drm plane state
+ * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
+ * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
+ * @can_position: is it legal to position the plane such that it
+ *                doesn't cover the entire crtc?  This will generally
+ *                only be false for primary planes.
+ * @can_update_disabled: can the plane be updated while the crtc
+ *                       is disabled?
+ *
+ * Provide a default plane check update handler
+ *
+ * RETURNS:
+ * Zero on success, error code on failure
+ */
+int drm_atomic_helper_plane_check_update(struct drm_plane *plane,
+					 struct drm_plane_state *state,
+					 int min_scale,
+					 int max_scale,
+					 bool can_position,
+					 bool can_update_disabled,
+					 bool *visible)
+{
+	struct drm_crtc *crtc = state->crtc;
+	struct drm_framebuffer *fb = state->fb;
+
+	if (!fb)
+		return 0;
+
+	struct drm_rect src = {
+		.x1 = state->src_x,
+		.y1 = state->src_y,
+		.x2 = state->src_x + state->src_w,
+		.y2 = state->src_y + state->src_h,
+	};
+	struct drm_rect dest = {
+		.x1 = state->crtc_x,
+		.y1 = state->crtc_y,
+		.x2 = state->crtc_x + state->crtc_w,
+		.y2 = state->crtc_y + state->crtc_h,
+	};
+	const struct drm_rect clip = {
+		.x2 = crtc->mode.hdisplay,
+		.y2 = crtc->mode.vdisplay,
+	};
+
+	return drm_plane_helper_check_update(plane, crtc, fb,
+			&src, &dest, &clip,
+			min_scale, max_scale,
+			can_position, can_update_disabled, visible);
+}
+EXPORT_SYMBOL(drm_atomic_helper_plane_check_update);
+
+/**
  * drm_atomic_helper_update_plane - Helper for primary plane update using atomic
  * @plane: plane object to update
  * @crtc: owning CRTC of owning plane
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index cc1fee8..5305a01 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -64,6 +64,13 @@ void drm_atomic_helper_swap_state(struct drm_device *dev,
 				  struct drm_atomic_state *state);
 
 /* implementations for legacy interfaces */
+int drm_atomic_helper_plane_check_update(struct drm_plane *plane,
+					 struct drm_plane_state *state,
+					 int min_scale,
+					 int max_scale,
+					 bool can_position,
+					 bool can_update_disabled,
+					 bool *visible);
 int drm_atomic_helper_update_plane(struct drm_plane *plane,
 				   struct drm_crtc *crtc,
 				   struct drm_framebuffer *fb,
-- 
1.7.10.4