drm/exynos: wait all planes updates to finish

Add infrastructure to wait for all planes updates to finish by using
an atomic_t variable to track how many pending updates we are waiting
plus a wait_queue for the wait part.

It also changes vblank behaviour and keeps it enabled for all types
of updates

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

4 files changed, 61 insertions, 6 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index 582e041a9356..d6c2c3f8bc6e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -75,10 +75,7 @@ static void exynos_crtc_atomic_begin(struct drm_crtc *crtc,
         struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
         struct drm_plane *plane;
 
-        if (crtc->state->event) {
-                WARN_ON(drm_crtc_vblank_get(crtc) != 0);
-                exynos_crtc->event = crtc->state->event;
-        }
+        exynos_crtc->event = crtc->state->event;
 
         drm_atomic_crtc_for_each_plane(plane, crtc) {
                 struct exynos_drm_plane *exynos_plane = to_exynos_plane(plane);
@@ -156,6 +153,8 @@ struct exynos_drm_crtc *exynos_drm_crtc_create(struct drm_device *drm_dev,
         exynos_crtc->ops = ops;
         exynos_crtc->ctx = ctx;
 
+        init_waitqueue_head(&exynos_crtc->wait_update);
+
         crtc = &exynos_crtc->base;
 
         private->crtc[pipe] = crtc;
@@ -197,6 +196,13 @@ void exynos_drm_crtc_disable_vblank(struct drm_device *dev, int pipe)
                 exynos_crtc->ops->disable_vblank(exynos_crtc);
 }
 
+void exynos_drm_crtc_wait_pending_update(struct exynos_drm_crtc *exynos_crtc)
+{
+        wait_event_timeout(exynos_crtc->wait_update,
+                           (atomic_read(&exynos_crtc->pending_update) == 0),
+                           msecs_to_jiffies(50));
+}
+
 void exynos_drm_crtc_finish_update(struct exynos_drm_crtc *exynos_crtc,
                                 struct exynos_drm_plane *exynos_plane)
 {
@@ -205,10 +211,12 @@ void exynos_drm_crtc_finish_update(struct exynos_drm_crtc *exynos_crtc,
 
         exynos_plane->pending_fb = NULL;
 
+        if (atomic_dec_and_test(&exynos_crtc->pending_update))
+                wake_up(&exynos_crtc->wait_update);
+
         spin_lock_irqsave(&crtc->dev->event_lock, flags);
         if (exynos_crtc->event) {
                 drm_crtc_send_vblank_event(crtc, exynos_crtc->event);
-                drm_crtc_vblank_put(crtc);
                 wake_up(&exynos_crtc->pending_flip_queue);
         }
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.h b/drivers/gpu/drm/exynos/exynos_drm_crtc.h
index 8bedfde2084a..f87d4abda6f7 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.h
@@ -25,6 +25,7 @@ struct exynos_drm_crtc *exynos_drm_crtc_create(struct drm_device *drm_dev,
                                         void *context);
 int exynos_drm_crtc_enable_vblank(struct drm_device *dev, int pipe);
 void exynos_drm_crtc_disable_vblank(struct drm_device *dev, int pipe);
+void exynos_drm_crtc_wait_pending_update(struct exynos_drm_crtc *exynos_crtc);
 void exynos_drm_crtc_finish_update(struct exynos_drm_crtc *exynos_crtc,
                                    struct exynos_drm_plane *exynos_plane);
 void exynos_drm_crtc_complete_scanout(struct drm_framebuffer *fb);
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
index 898591792b12..1350c8e2d587 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -45,11 +45,37 @@ struct exynos_atomic_commit {
         u32                     crtcs;
 };
 
+static void exynos_atomic_wait_for_commit(struct drm_atomic_state *state)
+{
+        struct drm_crtc_state *crtc_state;
+        struct drm_crtc *crtc;
+        int i, ret;
+
+        for_each_crtc_in_state(state, crtc, crtc_state, i) {
+                struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
+
+                if (!crtc->state->enable)
+                        continue;
+
+                ret = drm_crtc_vblank_get(crtc);
+                if (ret)
+                        continue;
+
+                exynos_drm_crtc_wait_pending_update(exynos_crtc);
+                drm_crtc_vblank_put(crtc);
+        }
+}
+
 static void exynos_atomic_commit_complete(struct exynos_atomic_commit *commit)
 {
         struct drm_device *dev = commit->dev;
         struct exynos_drm_private *priv = dev->dev_private;
         struct drm_atomic_state *state = commit->state;
+        struct drm_plane *plane;
+        struct drm_crtc *crtc;
+        struct drm_plane_state *plane_state;
+        struct drm_crtc_state *crtc_state;
+        int i;
 
         drm_atomic_helper_commit_modeset_disables(dev, state);
 
@@ -63,9 +89,25 @@ static void exynos_atomic_commit_complete(struct exynos_atomic_commit *commit)
          * have the relevant clocks enabled to perform the update.
          */
 
+        for_each_crtc_in_state(state, crtc, crtc_state, i) {
+                struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
+
+                atomic_set(&exynos_crtc->pending_update, 0);
+        }
+
+        for_each_plane_in_state(state, plane, plane_state, i) {
+                struct exynos_drm_crtc *exynos_crtc =
+                                                to_exynos_crtc(plane->crtc);
+
+                if (!plane->crtc)
+                        continue;
+
+                atomic_inc(&exynos_crtc->pending_update);
+        }
+
         drm_atomic_helper_commit_planes(dev, state);
 
-        drm_atomic_helper_wait_for_vblanks(dev, state);
+        exynos_atomic_wait_for_commit(state);
 
         drm_atomic_helper_cleanup_planes(dev, state);
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.h b/drivers/gpu/drm/exynos/exynos_drm_drv.h
index b06fbd43b475..7193d94fde3b 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.h
@@ -136,6 +136,8 @@ struct exynos_drm_crtc_ops {
  *      this pipe value.
  * @enabled: if the crtc is enabled or not
  * @event: vblank event that is currently queued for flip
+ * @wait_update: wait all pending planes updates to finish
+ * @pending_update: number of pending plane updates in this crtc
  * @ops: pointer to callbacks for exynos drm specific functionality
  * @ctx: A pointer to the crtc's implementation specific context
  */
@@ -145,6 +147,8 @@ struct exynos_drm_crtc {
         unsigned int                    pipe;
         wait_queue_head_t               pending_flip_queue;
         struct drm_pending_vblank_event *event;
+        wait_queue_head_t               wait_update;
+        atomic_t                        pending_update;
         const struct exynos_drm_crtc_ops        *ops;
         void                            *ctx;
 };