[PATCH 1/3] drm/arm: hdlcd: properly validate plane state

[Russell King]

The hdlcd crtc is unable to place planes in arbitary positions and sizes
within the active area.  Use drm_plane_helper_check_state() to validate
the requested state.

Suggested-by: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
---
 drivers/gpu/drm/arm/hdlcd_crtc.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
index 7d4e5aa77195..ba68fa2b5701 100644
--- a/drivers/gpu/drm/arm/hdlcd_crtc.c
+++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
@@ -10,6 +10,7 @@
  */
 
 #include <drm/drmP.h>
+#include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
@@ -205,13 +206,30 @@ static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
 static int hdlcd_plane_atomic_check(struct drm_plane *plane,
 				    struct drm_plane_state *state)
 {
-	u32 src_w, src_h;
+	struct drm_crtc_state *crtc_state;
+	struct drm_crtc *crtc;
+	struct drm_rect clip = { 0 };
+	int ret;
+
+	crtc = state->crtc;
+	if (!crtc)
+		return 0;
 
-	src_w = state->src_w >> 16;
-	src_h = state->src_h >> 16;
+	crtc_state = drm_atomic_get_existing_crtc_state(state->state, crtc);
+	if (!crtc_state->enable)
+		return -EINVAL;
+
+	clip.x2 = crtc_state->adjusted_mode.hdisplay;
+	clip.y2 = crtc_state->adjusted_mode.vdisplay;
+
+	ret = drm_plane_helper_check_state(state, &clip,
+					   DRM_PLANE_HELPER_NO_SCALING,
+					   DRM_PLANE_HELPER_NO_SCALING,
+					   false, true);
+	if (ret)
+		return ret;
 
-	/* we can't do any scaling of the plane source */
-	if ((src_w != state->crtc_w) || (src_h != state->crtc_h))
+	if (!state->visible)
 		return -EINVAL;
 
 	return 0;
-- 
2.7.4