From c1819eeffb101131b21854362685c05b815baf3a Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 18 Apr 2012 22:54:50 +0100
Subject: [PATCH] drm/i915: i8xx interrupt handler

- 16bit IIR
- PendingFlip status bit

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=24202
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41793
---
 drivers/gpu/drm/i915/i915_irq.c |   94 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 53d1b6c..2931743 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1543,6 +1543,91 @@ static irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 	return ret;
 }
 
+static irqreturn_t i8xx_driver_irq_handler(DRM_IRQ_ARGS)
+{
+	struct drm_device *dev = (struct drm_device *) arg;
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	struct drm_i915_master_private *master_priv;
+	u16 iir, new_iir;
+	u32 pipe_stats[2];
+	unsigned long irqflags;
+	int irq_received;
+	int pipe;
+	u16 flip_mask =
+		I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
+		I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;
+
+	atomic_inc(&dev_priv->irq_received);
+
+	iir = I915_READ16(IIR);
+	if (iir == 0)
+		return IRQ_NONE;
+
+	while (iir & ~flip_mask) {
+		/* Can't rely on pipestat interrupt bit in iir as it might
+		 * have been cleared after the pipestat interrupt was received.
+		 * It doesn't set the bit in iir again, but it still produces
+		 * interrupts (for non-MSI).
+		 */
+		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
+			i915_handle_error(dev, false);
+
+		for_each_pipe(pipe) {
+			int reg = PIPESTAT(pipe);
+			pipe_stats[pipe] = I915_READ(reg);
+
+			/*
+			 * Clear the PIPE*STAT regs before the IIR
+			 */
+			if (pipe_stats[pipe] & 0x8000ffff) {
+				if (pipe_stats[pipe] & PIPE_FIFO_UNDERRUN_STATUS)
+					DRM_DEBUG_DRIVER("pipe %c underrun\n",
+							 pipe_name(pipe));
+				I915_WRITE(reg, pipe_stats[pipe]);
+				irq_received = 1;
+			}
+		}
+		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+		I915_WRITE16(IIR, iir & ~flip_mask);
+		new_iir = I915_READ16(IIR); /* Flush posted writes */
+
+		if (dev->primary->master) {
+			master_priv = dev->primary->master->driver_priv;
+			if (master_priv->sarea_priv)
+				master_priv->sarea_priv->last_dispatch =
+					READ_BREADCRUMB(dev_priv);
+		}
+
+		if (iir & I915_USER_INTERRUPT)
+			notify_ring(dev, &dev_priv->ring[RCS]);
+
+		if (pipe_stats[0] & PIPE_VBLANK_INTERRUPT_STATUS &&
+		    drm_handle_vblank(dev, 0)) {
+			if (iir & I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT) {
+				intel_prepare_page_flip(dev, 0);
+				intel_finish_page_flip(dev, 0);
+				flip_mask &= ~I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT;
+			}
+		}
+
+		if (pipe_stats[1] & PIPE_VBLANK_INTERRUPT_STATUS &&
+		    drm_handle_vblank(dev, 1)) {
+			if (iir & I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT) {
+				intel_prepare_page_flip(dev, 1);
+				intel_finish_page_flip(dev, 1);
+				flip_mask &= ~I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;
+			}
+		}
+
+		iir = new_iir;
+	}
+
+	return IRQ_HANDLED;
+
+}
+
 static int i915_emit_irq(struct drm_device * dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
@@ -2352,6 +2437,10 @@ static int i915_driver_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(EMR, error_mask);
 
 	I915_WRITE(IMR, dev_priv->irq_mask);
+	if (IS_GEN2(dev)) {
+		enable_mask &= ~(I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
+				 I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT);
+	}
 	I915_WRITE(IER, enable_mask);
 	POSTING_READ(IER);
 
@@ -2508,7 +2597,10 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->irq_preinstall = i915_driver_irq_preinstall;
 		dev->driver->irq_postinstall = i915_driver_irq_postinstall;
 		dev->driver->irq_uninstall = i915_driver_irq_uninstall;
-		dev->driver->irq_handler = i915_driver_irq_handler;
+		if (INTEL_INFO(dev)->gen == 2)
+			dev->driver->irq_handler = i8xx_driver_irq_handler;
+		else
+			dev->driver->irq_handler = i915_driver_irq_handler;
 		dev->driver->enable_vblank = i915_enable_vblank;
 		dev->driver->disable_vblank = i915_disable_vblank;
 	}
-- 
1.7.10