[PATCH] drm/sti: forbid plane on several mixer

[Vincent Abriou]

When a plane is going to be enabled we re-evaluate the possible crtcs
for the associated drm plane. Only the crtc on which the plane should be
displayed is considered possible until the plane is disabled.
Indeed STI hardware does not allow to dynamically change
the plane's crtc/mixer assignment when the plane is in use (gdp is
running).

Signed-off-by: Vincent Abriou <vincent.abriou at st.com>
---
 drivers/gpu/drm/sti/sti_gdp.c   | 15 +++++++++++++++
 drivers/gpu/drm/sti/sti_plane.h |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/sti/sti_gdp.c b/drivers/gpu/drm/sti/sti_gdp.c
index 3fc62c1..f7cd671 100644
--- a/drivers/gpu/drm/sti/sti_gdp.c
+++ b/drivers/gpu/drm/sti/sti_gdp.c
@@ -71,6 +71,9 @@ static struct gdp_format_to_str {
 #define GDP_NODE_NB_BANK        2
 #define GDP_NODE_PER_FIELD      2
 
+#define MAIN_CRTC_MASK          BIT(0)
+#define AUX_CRTC_MASK           BIT(1)
+
 struct sti_gdp_node {
 	u32 gam_gdp_ctl;
 	u32 gam_gdp_agc;
@@ -690,6 +693,12 @@ static int sti_gdp_atomic_check(struct drm_plane *drm_plane,
 		}
 	}
 
+	/* re-evaluate the possible crtcs */
+	if (mixer->id == STI_MIXER_MAIN)
+		drm_plane->possible_crtcs = MAIN_CRTC_MASK;
+	else
+		drm_plane->possible_crtcs = AUX_CRTC_MASK;
+
 	DRM_DEBUG_KMS("CRTC:%d (%s) drm plane:%d (%s)\n",
 		      crtc->base.id, sti_mixer_to_str(mixer),
 		      drm_plane->base.id, sti_plane_to_str(plane));
@@ -846,6 +855,9 @@ static void sti_gdp_atomic_disable(struct drm_plane *drm_plane,
 {
 	struct sti_plane *plane = to_sti_plane(drm_plane);
 
+	/* restore possible crtcs value with the initial value */
+	drm_plane->possible_crtcs = plane->init_possible_crtcs;
+
 	if (!drm_plane->crtc) {
 		DRM_DEBUG_DRIVER("drm plane:%d not enabled\n",
 				 drm_plane->base.id);
@@ -917,6 +929,9 @@ struct drm_plane *sti_gdp_create(struct drm_device *drm_dev,
 
 	sti_gdp_init(gdp);
 
+	/* store the initial value of possible crtcs */
+	gdp->plane.init_possible_crtcs = possible_crtcs;
+
 	res = drm_universal_plane_init(drm_dev, &gdp->plane.drm_plane,
 				       possible_crtcs,
 				       &sti_gdp_plane_helpers_funcs,
diff --git a/drivers/gpu/drm/sti/sti_plane.h b/drivers/gpu/drm/sti/sti_plane.h
index ce3e8d6..70c5312 100644
--- a/drivers/gpu/drm/sti/sti_plane.h
+++ b/drivers/gpu/drm/sti/sti_plane.h
@@ -66,12 +66,14 @@ struct sti_fps_info {
  * @plane:              drm plane it is bound to (if any)
  * @desc:               plane type & id
  * @status:             to know the status of the plane
+ * @init_possile_crtcs: store the initial possible crtc value
  * @fps_info:           frame per second info
  */
 struct sti_plane {
 	struct drm_plane drm_plane;
 	enum sti_plane_desc desc;
 	enum sti_plane_status status;
+	u32 init_possible_crtcs;
 	struct sti_fps_info fps_info;
 };
 
-- 
1.9.1