From bd00301e51dd2e7c3ba4721dbbbd8f17dc695e14 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 1 Jun 2020 15:03:55 +0100
Subject: drm/i915: Trim the ironlake+ irq handler
Git-commit: c48a798a74476877477d7597726308cc2c8e9e07
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Ever noticed that our interrupt handlers are where we spend most of our
time on a busy system? In part this is unavoidable as each interrupt
requires to poll and reset several registers, but we can try and do so as
efficiently as possible.

Function                                     old     new   delta
ilk_irq_handler                             2317    2156    -161

v2: Restore the irqreturn_t ret

Function                                     old     new   delta
ilk_irq_handler.cold                          63      72      +9
ilk_irq_handler                             2221    2080    -141

A slight improvement in the baseline overnight as well!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200601140355.20243-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c | 57 +++++++++++++++++----------------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e03b80f85198..a31660756b98 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2097,67 +2097,68 @@ static void ivb_display_irq_handler(struct drm_i915_private *dev_priv,
  */
 static irqreturn_t ilk_irq_handler(int irq, void *arg)
 {
-	struct drm_i915_private *dev_priv = arg;
+	struct drm_i915_private *i915 = arg;
+	void __iomem * const regs = i915->uncore.regs;
 	u32 de_iir, gt_iir, de_ier, sde_ier = 0;
 	irqreturn_t ret = IRQ_NONE;
 
-	if (!intel_irqs_enabled(dev_priv))
+	if (unlikely(!intel_irqs_enabled(i915)))
 		return IRQ_NONE;
 
 	/* IRQs are synced during runtime_suspend, we don't require a wakeref */
-	disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
+	disable_rpm_wakeref_asserts(&i915->runtime_pm);
 
 	/* disable master interrupt before clearing iir  */
-	de_ier = I915_READ(DEIER);
-	I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
+	de_ier = raw_reg_read(regs, DEIER);
+	raw_reg_write(regs, DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
 
 	/* Disable south interrupts. We'll only write to SDEIIR once, so further
 	 * interrupts will will be stored on its back queue, and then we'll be
 	 * able to process them after we restore SDEIER (as soon as we restore
 	 * it, we'll get an interrupt if SDEIIR still has something to process
 	 * due to its back queue). */
-	if (!HAS_PCH_NOP(dev_priv)) {
-		sde_ier = I915_READ(SDEIER);
-		I915_WRITE(SDEIER, 0);
+	if (!HAS_PCH_NOP(i915)) {
+		sde_ier = raw_reg_read(regs, SDEIER);
+		raw_reg_write(regs, SDEIER, 0);
 	}
 
 	/* Find, clear, then process each source of interrupt */
 
-	gt_iir = I915_READ(GTIIR);
+	gt_iir = raw_reg_read(regs, GTIIR);
 	if (gt_iir) {
-		I915_WRITE(GTIIR, gt_iir);
-		ret = IRQ_HANDLED;
-		if (INTEL_GEN(dev_priv) >= 6)
-			gen6_gt_irq_handler(&dev_priv->gt, gt_iir);
+		raw_reg_write(regs, GTIIR, gt_iir);
+		if (INTEL_GEN(i915) >= 6)
+			gen6_gt_irq_handler(&i915->gt, gt_iir);
 		else
-			gen5_gt_irq_handler(&dev_priv->gt, gt_iir);
+			gen5_gt_irq_handler(&i915->gt, gt_iir);
+		ret = IRQ_HANDLED;
 	}
 
-	de_iir = I915_READ(DEIIR);
+	de_iir = raw_reg_read(regs, DEIIR);
 	if (de_iir) {
-		I915_WRITE(DEIIR, de_iir);
-		ret = IRQ_HANDLED;
-		if (INTEL_GEN(dev_priv) >= 7)
-			ivb_display_irq_handler(dev_priv, de_iir);
+		raw_reg_write(regs, DEIIR, de_iir);
+		if (INTEL_GEN(i915) >= 7)
+			ivb_display_irq_handler(i915, de_iir);
 		else
-			ilk_display_irq_handler(dev_priv, de_iir);
+			ilk_display_irq_handler(i915, de_iir);
+		ret = IRQ_HANDLED;
 	}
 
-	if (INTEL_GEN(dev_priv) >= 6) {
-		u32 pm_iir = I915_READ(GEN6_PMIIR);
+	if (INTEL_GEN(i915) >= 6) {
+		u32 pm_iir = raw_reg_read(regs, GEN6_PMIIR);
 		if (pm_iir) {
-			I915_WRITE(GEN6_PMIIR, pm_iir);
+			raw_reg_write(regs, GEN6_PMIIR, pm_iir);
+			gen6_rps_irq_handler(&i915->gt.rps, pm_iir);
 			ret = IRQ_HANDLED;
-			gen6_rps_irq_handler(&dev_priv->gt.rps, pm_iir);
 		}
 	}
 
-	I915_WRITE(DEIER, de_ier);
-	if (!HAS_PCH_NOP(dev_priv))
-		I915_WRITE(SDEIER, sde_ier);
+	raw_reg_write(regs, DEIER, de_ier);
+	if (sde_ier)
+		raw_reg_write(regs, SDEIER, sde_ier);
 
 	/* IRQs are synced during runtime_suspend, we don't require a wakeref */
-	enable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
+	enable_rpm_wakeref_asserts(&i915->runtime_pm);
 
 	return ret;
 }
-- 
2.29.2