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>

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);

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;
 

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 &&

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,