From 3af71f649d22f359790b4032446456a967a81742 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 8 Aug 2018 22:08:42 +0100
Subject: drm/i915: Restore user forcewake domains across suspend
References: bsc#1100132
Patch-mainline: v4.18-rc7
Git-commit: 3af71f649d22f359790b4032446456a967a81742

On suspend, we cancel the automatic forcewake and clear all other sources
of forcewake so the machine can sleep before we do suspend. However, we
expose the forcewake to userspace (only via debugfs, but nevertheless we
do) and want to restore that upon resume or else our accounting will be
off and we may not acquire the forcewake before we use it. So record
which domains we cleared on suspend and reacquire them early on resume.

v2: Hold the spinlock to appease our sanitychecks
v3: s/fw_domains_user/fw_domains_saved/ to convey intent more clearly

Backport notes:

  * Adapted patch to changes in context.

Reported-by: Imre Deak <imre.deak@linux.intel.com>
Fixes: b8473050805f ("drm/i915: Fix forcewake active domain tracking")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Imre Deak <imre.deak@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180808210842.3555-1-chris@chris-wilson.co.uk
(cherry picked from commit d60996ab430c8a6033a0944c068edc5ec5becb9b)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/i915/intel_uncore.c           |   46 ++++++++++++++------------
 drivers/gpu/drm/i915/intel_uncore.h           |    1
 drivers/gpu/drm/i915/selftests/intel_uncore.c |    2 -
 3 files changed, 28 insertions(+), 21 deletions(-)

--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -345,8 +345,8 @@ intel_uncore_fw_release_timer(struct hrt
 	return HRTIMER_NORESTART;
 }

-static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
-					 bool restore)
+static unsigned int
+intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv)
 {
 	unsigned long irqflags;
 	struct intel_uncore_forcewake_domain *domain;
@@ -396,20 +396,11 @@ static void intel_uncore_forcewake_reset
 		dev_priv->uncore.funcs.force_wake_put(dev_priv, fw);

 	fw_domains_reset(dev_priv, dev_priv->uncore.fw_domains);
-
-	if (restore) { /* If reset with a user forcewake, try to restore */
-		if (fw)
-			dev_priv->uncore.funcs.force_wake_get(dev_priv, fw);
-
-		if (IS_GEN6(dev_priv) || IS_GEN7(dev_priv))
-			dev_priv->uncore.fifo_count =
-				fifo_free_entries(dev_priv);
-	}
-
-	if (!restore)
-		assert_forcewakes_inactive(dev_priv);
+	assert_forcewakes_inactive(dev_priv);

 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
+
+	return fw; /* track the lost user forcewake domains */
 }

 static u64 gen9_edram_size(struct drm_i915_private *dev_priv)
@@ -518,7 +509,7 @@ check_for_unclaimed_mmio(struct drm_i915
 }

 static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
-					  bool restore_forcewake)
+					  unsigned int restore_forcewake)
 {
 	/* clear out unclaimed reg detection bit */
 	if (check_for_unclaimed_mmio(dev_priv))
@@ -532,19 +523,34 @@ static void __intel_uncore_early_sanitiz
 				   GT_FIFO_CTL_RC6_POLICY_STALL);
 	}

-	intel_uncore_forcewake_reset(dev_priv, restore_forcewake);
+	intel_uncore_forcewake_reset(dev_priv);
+	if (restore_forcewake) {
+		spin_lock_irq(&dev_priv->uncore.lock);
+		dev_priv->uncore.funcs.force_wake_get(dev_priv,
+						      restore_forcewake);
+
+		if (IS_GEN6(dev_priv) || IS_GEN7(dev_priv))
+			dev_priv->uncore.fifo_count =
+				fifo_free_entries(dev_priv);
+		spin_unlock_irq(&dev_priv->uncore.lock);
+	}
 }

 void intel_uncore_suspend(struct drm_i915_private *dev_priv)
 {
 	iosf_mbi_unregister_pmic_bus_access_notifier(
 		&dev_priv->uncore.pmic_bus_access_nb);
-	intel_uncore_forcewake_reset(dev_priv, false);
+	dev_priv->uncore.fw_domains_saved =
+		intel_uncore_forcewake_reset(dev_priv);
 }

 void intel_uncore_resume_early(struct drm_i915_private *dev_priv)
 {
-	__intel_uncore_early_sanitize(dev_priv, true);
+	unsigned int restore_forcewake;
+
+	restore_forcewake = fetch_and_zero(&dev_priv->uncore.fw_domains_saved);
+	__intel_uncore_early_sanitize(dev_priv, restore_forcewake);
+
 	iosf_mbi_register_pmic_bus_access_notifier(
 		&dev_priv->uncore.pmic_bus_access_nb);
 	i915_check_and_clear_faults(dev_priv);
@@ -1384,7 +1390,7 @@ void intel_uncore_init(struct drm_i915_p

 	intel_uncore_edram_detect(dev_priv);
 	intel_uncore_fw_domains_init(dev_priv);
-	__intel_uncore_early_sanitize(dev_priv, false);
+	__intel_uncore_early_sanitize(dev_priv, 0);

 	dev_priv->uncore.unclaimed_mmio_check = 1;
 	dev_priv->uncore.pmic_bus_access_nb.notifier_call =
@@ -1432,7 +1438,7 @@ void intel_uncore_fini(struct drm_i915_p

 	/* Paranoia: make sure we have disabled everything before we exit. */
 	intel_uncore_sanitize(dev_priv);
-	intel_uncore_forcewake_reset(dev_priv, false);
+	intel_uncore_forcewake_reset(dev_priv);
 }

 static const struct reg_whitelist {
--- a/drivers/gpu/drm/i915/intel_uncore.h
+++ b/drivers/gpu/drm/i915/intel_uncore.h
@@ -93,6 +93,7 @@ struct intel_uncore {

 	enum forcewake_domains fw_domains;
 	enum forcewake_domains fw_domains_active;
+	enum forcewake_domains fw_domains_saved; /* user domains saved for S3 */

 	u32 fw_set;
 	u32 fw_clear;
--- a/drivers/gpu/drm/i915/selftests/intel_uncore.c
+++ b/drivers/gpu/drm/i915/selftests/intel_uncore.c
@@ -148,7 +148,7 @@ static int intel_uncore_check_forcewake_
 	for_each_set_bit(offset, valid, FW_RANGE) {
 		i915_reg_t reg = { offset };

-		intel_uncore_forcewake_reset(dev_priv, false);
+		intel_uncore_forcewake_reset(dev_priv);
 		check_for_unclaimed_mmio(dev_priv);

 		(void)I915_READ(reg);