drm: omapdrm: new vblank and event handling

Rework the crtc event/flip_wait system as follows:

- If we enable a crtc (full modeset), we set omap_crtc->pending and
  register vblank irq.

- If we need to set GO bit (page flip), we do the same but also set the
  GO bit.

- On vblank we unregister the irq, clear the 'pending' flag, send vblank
  event to userspace if crtc->state->event != NULL, and wake up
  'pending_wait' wq.

- In omap_atomic_complete() we wait for the 'pending' flag to get reset
  for all enabled crtcs  using 'pending_wait' wq.

The above ensures that we send the events to userspace in vblank, and
that after the wait in omap_atomic_complete() everything for the
affected crtcs has been completed.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

3 files changed, 70 insertions, 76 deletions

diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
index 8d2bf8565ddd..23d9c928cdc9 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.c
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
@@ -17,8 +17,6 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <linux/completion.h>
-
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
@@ -49,13 +47,10 @@ struct omap_crtc {
         struct omap_drm_irq vblank_irq;
         struct omap_drm_irq error_irq;
 
-        /* pending event */
-        struct drm_pending_vblank_event *event;
-        wait_queue_head_t flip_wait;
-
-        struct completion completion;
-
         bool ignore_digit_sync_lost;
+
+        bool pending;
+        wait_queue_head_t pending_wait;
 };
 
 /* -----------------------------------------------------------------------------
@@ -81,6 +76,15 @@ enum omap_channel omap_crtc_channel(struct drm_crtc *crtc)
         return omap_crtc->channel;
 }
 
+int omap_crtc_wait_pending(struct drm_crtc *crtc)
+{
+        struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+
+        return wait_event_timeout(omap_crtc->pending_wait,
+                                  !omap_crtc->pending,
+                                  msecs_to_jiffies(50));
+}
+
 /* -----------------------------------------------------------------------------
  * DSS Manager Functions
  */
@@ -255,61 +259,29 @@ static const struct dss_mgr_ops mgr_ops = {
 
 static void omap_crtc_complete_page_flip(struct drm_crtc *crtc)
 {
-        struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
         struct drm_pending_vblank_event *event;
         struct drm_device *dev = crtc->dev;
         unsigned long flags;
 
-        spin_lock_irqsave(&dev->event_lock, flags);
-
-        event = omap_crtc->event;
-        omap_crtc->event = NULL;
+        event = crtc->state->event;
 
-        if (event) {
-                list_del(&event->base.link);
-
-                /*
-                 * Queue the event for delivery if it's still linked to a file
-                 * handle, otherwise just destroy it.
-                 */
-                if (event->base.file_priv)
-                        drm_crtc_send_vblank_event(crtc, event);
-                else
-                        event->base.destroy(&event->base);
-
-                wake_up(&omap_crtc->flip_wait);
-                drm_crtc_vblank_put(crtc);
-        }
-
-        spin_unlock_irqrestore(&dev->event_lock, flags);
-}
-
-static bool omap_crtc_page_flip_pending(struct drm_crtc *crtc)
-{
-        struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
-        struct drm_device *dev = crtc->dev;
-        unsigned long flags;
-        bool pending;
+        if (!event)
+                return;
 
         spin_lock_irqsave(&dev->event_lock, flags);
-        pending = omap_crtc->event != NULL;
-        spin_unlock_irqrestore(&dev->event_lock, flags);
 
-        return pending;
-}
+        list_del(&event->base.link);
 
-static void omap_crtc_wait_page_flip(struct drm_crtc *crtc)
-{
-        struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
-
-        if (wait_event_timeout(omap_crtc->flip_wait,
-                               !omap_crtc_page_flip_pending(crtc),
-                               msecs_to_jiffies(50)))
-                return;
-
-        dev_warn(crtc->dev->dev, "page flip timeout!\n");
+        /*
+         * Queue the event for delivery if it's still linked to a file
+         * handle, otherwise just destroy it.
+         */
+        if (event->base.file_priv)
+                drm_crtc_send_vblank_event(crtc, event);
+        else
+                event->base.destroy(&event->base);
 
-        omap_crtc_complete_page_flip(crtc);
+        spin_unlock_irqrestore(&dev->event_lock, flags);
 }
 
 static void omap_crtc_error_irq(struct omap_drm_irq *irq, uint32_t irqstatus)
@@ -336,12 +308,19 @@ static void omap_crtc_vblank_irq(struct omap_drm_irq *irq, uint32_t irqstatus)
                 return;
 
         DBG("%s: apply done", omap_crtc->name);
+
         __omap_irq_unregister(dev, &omap_crtc->vblank_irq);
 
-        /* wakeup userspace */
+        rmb();
+        WARN_ON(!omap_crtc->pending);
+        omap_crtc->pending = false;
+        wmb();
+
+        /* wake up userspace */
         omap_crtc_complete_page_flip(&omap_crtc->base);
 
-        complete(&omap_crtc->completion);
+        /* wake up omap_atomic_complete */
+        wake_up(&omap_crtc->pending_wait);
 }
 
 /* -----------------------------------------------------------------------------
@@ -375,6 +354,13 @@ static void omap_crtc_enable(struct drm_crtc *crtc)
 
         DBG("%s", omap_crtc->name);
 
+        rmb();
+        WARN_ON(omap_crtc->pending);
+        omap_crtc->pending = true;
+        wmb();
+
+        omap_irq_register(crtc->dev, &omap_crtc->vblank_irq);
+
         drm_crtc_vblank_on(crtc);
 }
 
@@ -384,7 +370,6 @@ static void omap_crtc_disable(struct drm_crtc *crtc)
 
         DBG("%s", omap_crtc->name);
 
-        omap_crtc_wait_page_flip(crtc);
         drm_crtc_vblank_off(crtc);
 }
 
@@ -405,19 +390,6 @@ static void omap_crtc_mode_set_nofb(struct drm_crtc *crtc)
 
 static void omap_crtc_atomic_begin(struct drm_crtc *crtc)
 {
-        struct drm_pending_vblank_event *event = crtc->state->event;
-        struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
-        struct drm_device *dev = crtc->dev;
-        unsigned long flags;
-
-        if (event) {
-                WARN_ON(omap_crtc->event);
-                WARN_ON(drm_crtc_vblank_get(crtc) != 0);
-
-                spin_lock_irqsave(&dev->event_lock, flags);
-                omap_crtc->event = event;
-                spin_unlock_irqrestore(&dev->event_lock, flags);
-        }
 }
 
 static void omap_crtc_atomic_flush(struct drm_crtc *crtc)
@@ -427,14 +399,16 @@ static void omap_crtc_atomic_flush(struct drm_crtc *crtc)
         WARN_ON(omap_crtc->vblank_irq.registered);
 
         if (dispc_mgr_is_enabled(omap_crtc->channel)) {
+
                 DBG("%s: GO", omap_crtc->name);
 
+                rmb();
+                WARN_ON(omap_crtc->pending);
+                omap_crtc->pending = true;
+                wmb();
+
                 dispc_mgr_go(omap_crtc->channel);
                 omap_irq_register(crtc->dev, &omap_crtc->vblank_irq);
-
-                WARN_ON(!wait_for_completion_timeout(&omap_crtc->completion,
-                                                     msecs_to_jiffies(100)));
-                reinit_completion(&omap_crtc->completion);
         }
 
         crtc->invert_dimensions = !!(crtc->primary->state->rotation &
@@ -534,8 +508,7 @@ struct drm_crtc *omap_crtc_init(struct drm_device *dev,
 
         crtc = &omap_crtc->base;
 
-        init_waitqueue_head(&omap_crtc->flip_wait);
-        init_completion(&omap_crtc->completion);
+        init_waitqueue_head(&omap_crtc->pending_wait);
 
         omap_crtc->channel = channel;
         omap_crtc->name = channel_names[channel];
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index 50f555530e55..419c2e49adf5 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -66,6 +66,26 @@ struct omap_atomic_state_commit {
         u32 crtcs;
 };
 
+static void omap_atomic_wait_for_completion(struct drm_device *dev,
+                                            struct drm_atomic_state *old_state)
+{
+        struct drm_crtc_state *old_crtc_state;
+        struct drm_crtc *crtc;
+        unsigned int i;
+        int ret;
+
+        for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
+                if (!crtc->state->enable)
+                        continue;
+
+                ret = omap_crtc_wait_pending(crtc);
+
+                if (!ret)
+                        dev_warn(dev->dev,
+                                 "atomic complete timeout (pipe %u)!\n", i);
+        }
+}
+
 static void omap_atomic_complete(struct omap_atomic_state_commit *commit)
 {
         struct drm_device *dev = commit->dev;
@@ -79,7 +99,7 @@ static void omap_atomic_complete(struct omap_atomic_state_commit *commit)
         drm_atomic_helper_commit_planes(dev, old_state);
         drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
-        drm_atomic_helper_wait_for_vblanks(dev, old_state);
+        omap_atomic_wait_for_completion(dev, old_state);
 
         drm_atomic_helper_cleanup_planes(dev, old_state);
 
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
index 0b7a055bf007..ae2df41f216f 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.h
+++ b/drivers/gpu/drm/omapdrm/omap_drv.h
@@ -147,6 +147,7 @@ void omap_crtc_pre_init(void);
 void omap_crtc_pre_uninit(void);
 struct drm_crtc *omap_crtc_init(struct drm_device *dev,
                 struct drm_plane *plane, enum omap_channel channel, int id);
+int omap_crtc_wait_pending(struct drm_crtc *crtc);
 
 struct drm_plane *omap_plane_init(struct drm_device *dev,
                 int id, enum drm_plane_type type);