drm/i915: Remove intel_prepare_page_flip, v3.

Instead of calling prepare_flip right before calling finish_page_flip
do everything from prepare_page_flip in finish_page_flip.

Putting prepare and finish page_flip in a single step removes the need
for INTEL_FLIP_COMPLETE, so it can be removed. This simplifies the code
slightly.

Changes since v1:
- Invert if case to simplify code.
- Add missing barrier.
- Reword commit message.
Changes since v2:
- intel_page_flip_plane is removed.
- work->pending is turned into a bool.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-5-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>

4 files changed, 26 insertions, 73 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index f23b119a365d..6bff6b4daf99 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -619,12 +619,9 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
                         u32 addr;
 
                         pending = atomic_read(&work->pending);
-                        if (pending == INTEL_FLIP_INACTIVE) {
+                        if (pending) {
                                 seq_printf(m, "Flip ioctl preparing on pipe %c (plane %c)\n",
                                            pipe, plane);
-                        } else if (pending >= INTEL_FLIP_COMPLETE) {
-                                seq_printf(m, "Flip queued on pipe %c (plane %c)\n",
-                                           pipe, plane);
                         } else {
                                 seq_printf(m, "Flip pending (waiting for vsync) on pipe %c (plane %c)\n",
                                            pipe, plane);
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 920a5e4abb70..148741646fb0 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1705,10 +1705,8 @@ static void valleyview_pipestat_irq_handler(struct drm_i915_private *dev_priv,
                     intel_pipe_handle_vblank(dev_priv, pipe))
                         intel_check_page_flip(dev_priv, pipe);
 
-                if (pipe_stats[pipe] & PLANE_FLIP_DONE_INT_STATUS_VLV) {
-                        intel_prepare_page_flip(dev_priv, pipe);
+                if (pipe_stats[pipe] & PLANE_FLIP_DONE_INT_STATUS_VLV)
                         intel_finish_page_flip(dev_priv, pipe);
-                }
 
                 if (pipe_stats[pipe] & PIPE_CRC_DONE_INTERRUPT_STATUS)
                         i9xx_pipe_crc_irq_handler(dev_priv, pipe);
@@ -2162,10 +2160,8 @@ static void ilk_display_irq_handler(struct drm_i915_private *dev_priv,
                         i9xx_pipe_crc_irq_handler(dev_priv, pipe);
 
                 /* plane/pipes map 1:1 on ilk+ */
-                if (de_iir & DE_PLANE_FLIP_DONE(pipe)) {
-                        intel_prepare_page_flip(dev_priv, pipe);
+                if (de_iir & DE_PLANE_FLIP_DONE(pipe))
                         intel_finish_page_flip(dev_priv, pipe);
-                }
         }
 
         /* check event from PCH */
@@ -2209,10 +2205,8 @@ static void ivb_display_irq_handler(struct drm_i915_private *dev_priv,
                         intel_check_page_flip(dev_priv, pipe);
 
                 /* plane/pipes map 1:1 on ilk+ */
-                if (de_iir & DE_PLANE_FLIP_DONE_IVB(pipe)) {
-                        intel_prepare_page_flip(dev_priv, pipe);
+                if (de_iir & DE_PLANE_FLIP_DONE_IVB(pipe))
                         intel_finish_page_flip(dev_priv, pipe);
-                }
         }
 
         /* check event from PCH */
@@ -2417,10 +2411,8 @@ gen8_de_irq_handler(struct drm_i915_private *dev_priv, u32 master_ctl)
                 else
                         flip_done &= GEN8_PIPE_PRIMARY_FLIP_DONE;
 
-                if (flip_done) {
-                        intel_prepare_page_flip(dev_priv, pipe);
+                if (flip_done)
                         intel_finish_page_flip(dev_priv, pipe);
-                }
 
                 if (iir & GEN8_PIPE_CDCLK_CRC_DONE)
                         hsw_pipe_crc_irq_handler(dev_priv, pipe);
@@ -3998,7 +3990,6 @@ static bool i8xx_handle_vblank(struct drm_i915_private *dev_priv,
         if (I915_READ16(ISR) & flip_pending)
                 goto check_page_flip;
 
-        intel_prepare_page_flip(dev_priv, plane);
         intel_finish_page_flip(dev_priv, pipe);
         return true;
 
@@ -4188,7 +4179,6 @@ static bool i915_handle_vblank(struct drm_i915_private *dev_priv,
         if (I915_READ(ISR) & flip_pending)
                 goto check_page_flip;
 
-        intel_prepare_page_flip(dev_priv, plane);
         intel_finish_page_flip(dev_priv, pipe);
         return true;
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a298b8d137bf..ca2f51be8ef9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3112,10 +3112,8 @@ static void intel_complete_page_flips(struct drm_i915_private *dev_priv)
 {
         struct intel_crtc *crtc;
 
-        for_each_intel_crtc(dev_priv->dev, crtc) {
-                intel_prepare_page_flip(dev_priv, crtc->plane);
+        for_each_intel_crtc(dev_priv->dev, crtc)
                 intel_finish_page_flip(dev_priv, crtc->pipe);
-        }
 }
 
 static void intel_update_primary_planes(struct drm_device *dev)
@@ -10866,42 +10864,6 @@ static void intel_unpin_work_fn(struct work_struct *__work)
         kfree(work);
 }
 
-static void do_intel_finish_page_flip(struct drm_i915_private *dev_priv,
-                                      struct drm_crtc *crtc)
-{
-        struct drm_device *dev = dev_priv->dev;
-        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-        struct intel_unpin_work *work;
-        unsigned long flags;
-
-        /* Ignore early vblank irqs */
-        if (intel_crtc == NULL)
-                return;
-
-        /*
-         * This is called both by irq handlers and the reset code (to complete
-         * lost pageflips) so needs the full irqsave spinlocks.
-         */
-        spin_lock_irqsave(&dev->event_lock, flags);
-        work = intel_crtc->unpin_work;
-
-        if (work && atomic_read(&work->pending) >= INTEL_FLIP_COMPLETE) {
-                /* ensure that the unpin work is consistent wrt ->pending. */
-                smp_rmb();
-
-                page_flip_completed(intel_crtc);
-        }
-
-        spin_unlock_irqrestore(&dev->event_lock, flags);
-}
-
-void intel_finish_page_flip(struct drm_i915_private *dev_priv, int pipe)
-{
-        struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
-
-        do_intel_finish_page_flip(dev_priv, crtc);
-}
-
 /* Is 'a' after or equal to 'b'? */
 static bool g4x_flip_count_after_eq(u32 a, u32 b)
 {
@@ -10914,6 +10876,9 @@ static bool page_flip_finished(struct intel_crtc *crtc)
         struct drm_i915_private *dev_priv = dev->dev_private;
         unsigned reset_counter;
 
+        /* ensure that the unpin work is consistent wrt ->pending. */
+        smp_rmb();
+
         reset_counter = i915_reset_counter(&dev_priv->gpu_error);
         if (crtc->reset_counter != reset_counter)
                 return true;
@@ -10955,25 +10920,30 @@ static bool page_flip_finished(struct intel_crtc *crtc)
                                     crtc->unpin_work->flip_count);
 }
 
-void intel_prepare_page_flip(struct drm_i915_private *dev_priv, int plane)
+void intel_finish_page_flip(struct drm_i915_private *dev_priv, int pipe)
 {
         struct drm_device *dev = dev_priv->dev;
-        struct intel_crtc *intel_crtc =
-                to_intel_crtc(dev_priv->plane_to_crtc_mapping[plane]);
+        struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
+        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+        struct intel_unpin_work *work;
         unsigned long flags;
 
+        /* Ignore early vblank irqs */
+        if (!crtc)
+                return;
 
         /*
          * This is called both by irq handlers and the reset code (to complete
          * lost pageflips) so needs the full irqsave spinlocks.
-         *
-         * NB: An MMIO update of the plane base pointer will also
-         * generate a page-flip completion irq, i.e. every modeset
-         * is also accompanied by a spurious intel_prepare_page_flip().
          */
         spin_lock_irqsave(&dev->event_lock, flags);
-        if (intel_crtc->unpin_work && page_flip_finished(intel_crtc))
-                atomic_inc_not_zero(&intel_crtc->unpin_work->pending);
+        work = intel_crtc->unpin_work;
+
+        if (work != NULL &&
+            atomic_read(&work->pending) &&
+            page_flip_finished(intel_crtc))
+                page_flip_completed(intel_crtc);
+
         spin_unlock_irqrestore(&dev->event_lock, flags);
 }
 
@@ -10981,7 +10951,7 @@ static inline void intel_mark_page_flip_active(struct intel_unpin_work *work)
 {
         /* Ensure that the work item is consistent when activating it ... */
         smp_mb__before_atomic();
-        atomic_set(&work->pending, INTEL_FLIP_PENDING);
+        atomic_set(&work->pending, 1);
 }
 
 static int intel_gen2_queue_flip(struct drm_device *dev,
@@ -11421,8 +11391,8 @@ static bool __intel_pageflip_stall_check(struct drm_device *dev,
         /* ensure that the unpin work is consistent wrt ->pending. */
         smp_rmb();
 
-        if (pending != INTEL_FLIP_PENDING)
-                return pending == INTEL_FLIP_COMPLETE;
+        if (!pending)
+                return false;
 
         if (work->flip_ready_vblank == 0) {
                 if (work->flip_queued_req &&
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index ff268567cc0e..4541aa3f2943 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -984,9 +984,6 @@ struct intel_unpin_work {
         struct drm_i915_gem_object *pending_flip_obj;
         struct drm_pending_vblank_event *event;
         atomic_t pending;
-#define INTEL_FLIP_INACTIVE     0
-#define INTEL_FLIP_PENDING      1
-#define INTEL_FLIP_COMPLETE     2
         u32 flip_count;
         u32 gtt_offset;
         struct drm_i915_gem_request *flip_queued_req;
@@ -1199,7 +1196,6 @@ struct drm_framebuffer *
 __intel_framebuffer_create(struct drm_device *dev,
                            struct drm_mode_fb_cmd2 *mode_cmd,
                            struct drm_i915_gem_object *obj);
-void intel_prepare_page_flip(struct drm_i915_private *dev_priv, int plane);
 void intel_finish_page_flip(struct drm_i915_private *dev_priv, int pipe);
 void intel_check_page_flip(struct drm_i915_private *dev_priv, int pipe);
 int intel_prepare_plane_fb(struct drm_plane *plane,