drm/i915: Keep track of active forcewake domains in a bitmask

There are current places in the code, and there will be more in the
future, which iterate the forcewake domains to find out which ones
are currently active.

To save them from doing this iteration, we can cheaply keep a mask
of active domains in dev_priv->uncore.fw_domains_active.

This has no cost in terms of object size, even manages to shrink it
overall by 368 bytes on my config.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: "Paneri, Praveen" <praveen.paneri@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.h

@@ -588,7 +588,9 @@ struct intel_uncore {
 	struct intel_uncore_funcs funcs;
 
 	unsigned fifo_count;
+
 	enum forcewake_domains fw_domains;
+	enum forcewake_domains fw_domains_active;
 
 	struct intel_uncore_forcewake_domain {
 		struct drm_i915_private *i915;

drivers/gpu/drm/i915/intel_uncore.c

@@ -231,19 +231,21 @@ intel_uncore_fw_release_timer(struct hrtimer *timer)
 {
 	struct intel_uncore_forcewake_domain *domain =
 	       container_of(timer, struct intel_uncore_forcewake_domain, timer);
+	struct drm_i915_private *dev_priv = domain->i915;
 	unsigned long irqflags;
 
-	assert_rpm_device_not_suspended(domain->i915);
+	assert_rpm_device_not_suspended(dev_priv);
 
-	spin_lock_irqsave(&domain->i915->uncore.lock, irqflags);
+	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
 	if (WARN_ON(domain->wake_count == 0))
 		domain->wake_count++;
 
-	if (--domain->wake_count == 0)
-		domain->i915->uncore.funcs.force_wake_put(domain->i915,
-							  1 << domain->id);
+	if (--domain->wake_count == 0) {
+		dev_priv->uncore.funcs.force_wake_put(dev_priv, domain->mask);
+		dev_priv->uncore.fw_domains_active &= ~domain->mask;
+	}
 
-	spin_unlock_irqrestore(&domain->i915->uncore.lock, irqflags);
+	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 
 	return HRTIMER_NORESTART;
 }
@@ -254,7 +256,7 @@ void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
 	unsigned long irqflags;
 	struct intel_uncore_forcewake_domain *domain;
 	int retry_count = 100;
-	enum forcewake_domains fw = 0, active_domains;
+	enum forcewake_domains fw, active_domains;
 
 	/* Hold uncore.lock across reset to prevent any register access
 	 * with forcewake not set correctly. Wait until all pending
@@ -291,10 +293,7 @@ void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
 
 	WARN_ON(active_domains);
 
-	for_each_fw_domain(domain, dev_priv)
-		if (domain->wake_count)
-			fw |= domain->mask;
-
+	fw = dev_priv->uncore.fw_domains_active;
 	if (fw)
 		dev_priv->uncore.funcs.force_wake_put(dev_priv, fw);
 
@@ -443,9 +442,6 @@ static void __intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,
 {
 	struct intel_uncore_forcewake_domain *domain;
 
-	if (!dev_priv->uncore.funcs.force_wake_get)
-		return;
-
 	fw_domains &= dev_priv->uncore.fw_domains;
 
 	for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
@@ -453,8 +449,10 @@ static void __intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,
 			fw_domains &= ~domain->mask;
 	}
 
-	if (fw_domains)
+	if (fw_domains) {
 		dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains);
+		dev_priv->uncore.fw_domains_active |= fw_domains;
+	}
 }
 
 /**
@@ -509,9 +507,6 @@ static void __intel_uncore_forcewake_put(struct drm_i915_private *dev_priv,
 {
 	struct intel_uncore_forcewake_domain *domain;
 
-	if (!dev_priv->uncore.funcs.force_wake_put)
-		return;
-
 	fw_domains &= dev_priv->uncore.fw_domains;
 
 	for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
@@ -567,13 +562,10 @@ void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv,
 
 void assert_forcewakes_inactive(struct drm_i915_private *dev_priv)
 {
-	struct intel_uncore_forcewake_domain *domain;
-
 	if (!dev_priv->uncore.funcs.force_wake_get)
 		return;
 
-	for_each_fw_domain(domain, dev_priv)
-		WARN_ON(domain->wake_count);
+	WARN_ON(dev_priv->uncore.fw_domains_active);
 }
 
 /* We give fast paths for the really cool registers */
@@ -877,18 +869,18 @@ static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
 	if (WARN_ON(!fw_domains))
 		return;
 
-	/* Ideally GCC would be constant-fold and eliminate this loop */
-	for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
-		if (domain->wake_count) {
-			fw_domains &= ~domain->mask;
-			continue;
-		}
+	/* Turn on all requested but inactive supported forcewake domains. */
+	fw_domains &= dev_priv->uncore.fw_domains;
+	fw_domains &= ~dev_priv->uncore.fw_domains_active;
 
+	if (fw_domains) {
+		/* Ideally GCC would be constant-fold and eliminate this loop */
+		for_each_fw_domain_masked(domain, fw_domains, dev_priv)
 			fw_domain_arm_timer(domain);
-	}
 
-	if (fw_domains)
 		dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains);
+		dev_priv->uncore.fw_domains_active |= fw_domains;
+	}
 }
 
 #define __gen6_read(x) \