drm/i915: Skip unused fw_domains

Use find-first-set bitop to quickly scan through the fw_domains mask and
skip iterating over unused domains.

v2: Move the WARN into the caller, to prevent compiler warnings in
normal builds.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323101944.21627-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1461,9 +1461,10 @@ static int i915_forcewake_domains(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
 	struct intel_uncore_forcewake_domain *fw_domain;
+	unsigned int tmp;
 
 	spin_lock_irq(&dev_priv->uncore.lock);
-	for_each_fw_domain(fw_domain, dev_priv) {
+	for_each_fw_domain(fw_domain, dev_priv, tmp) {
 		seq_printf(m, "%s.wake_count = %u\n",
 			   intel_uncore_forcewake_domain_to_str(fw_domain->id),
 			   fw_domain->wake_count);

drivers/gpu/drm/i915/i915_drv.h

@@ -703,9 +703,9 @@ enum forcewake_domain_id {
 };
 
 enum forcewake_domains {
-	FORCEWAKE_RENDER = (1 << FW_DOMAIN_ID_RENDER),
-	FORCEWAKE_BLITTER = (1 << FW_DOMAIN_ID_BLITTER),
-	FORCEWAKE_MEDIA	= (1 << FW_DOMAIN_ID_MEDIA),
+	FORCEWAKE_RENDER = BIT(FW_DOMAIN_ID_RENDER),
+	FORCEWAKE_BLITTER = BIT(FW_DOMAIN_ID_BLITTER),
+	FORCEWAKE_MEDIA	= BIT(FW_DOMAIN_ID_MEDIA),
 	FORCEWAKE_ALL = (FORCEWAKE_RENDER |
 			 FORCEWAKE_BLITTER |
 			 FORCEWAKE_MEDIA)
@@ -790,15 +790,19 @@ struct intel_uncore {
 	int unclaimed_mmio_check;
 };
 
+#define __mask_next_bit(mask) ({					\
+	int __idx = ffs(mask) - 1;					\
+	mask &= ~BIT(__idx);						\
+	__idx;								\
+})
+
 /* Iterate over initialised fw domains */
-#define for_each_fw_domain_masked(domain__, mask__, dev_priv__) \
-	for ((domain__) = &(dev_priv__)->uncore.fw_domain[0]; \
-	     (domain__) < &(dev_priv__)->uncore.fw_domain[FW_DOMAIN_ID_COUNT]; \
-	     (domain__)++) \
-		for_each_if ((mask__) & (domain__)->mask)
+#define for_each_fw_domain_masked(domain__, mask__, dev_priv__, tmp__) \
+	for (tmp__ = (mask__); \
+	     tmp__ ? (domain__ = &(dev_priv__)->uncore.fw_domain[__mask_next_bit(tmp__)]), 1 : 0;)
 
-#define for_each_fw_domain(domain__, dev_priv__) \
-	for_each_fw_domain_masked(domain__, FORCEWAKE_ALL, dev_priv__)
+#define for_each_fw_domain(domain__, dev_priv__, tmp__) \
+	for_each_fw_domain_masked(domain__, (dev_priv__)->uncore.fw_domains, dev_priv__, tmp__)
 
 #define CSR_VERSION(major, minor)	((major) << 16 | (minor))
 #define CSR_VERSION_MAJOR(version)	((version) >> 16)
@@ -2581,12 +2585,6 @@ static inline struct drm_i915_private *huc_to_i915(struct intel_huc *huc)
 	     (id__)++) \
 		for_each_if ((engine__) = (dev_priv__)->engine[(id__)])
 
-#define __mask_next_bit(mask) ({					\
-	int __idx = ffs(mask) - 1;					\
-	mask &= ~BIT(__idx);						\
-	__idx;								\
-})
-
 /* Iterator over subset of engines selected by mask */
 #define for_each_engine_masked(engine__, dev_priv__, mask__, tmp__) \
 	for (tmp__ = mask__ & INTEL_INFO(dev_priv__)->ring_mask;	\

drivers/gpu/drm/i915/intel_uncore.c

@@ -118,13 +118,16 @@ static void
 fw_domains_get(struct drm_i915_private *i915, enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *d;
+	unsigned int tmp;
+
+	GEM_BUG_ON(fw_domains & ~i915->uncore.fw_domains);
 
-	for_each_fw_domain_masked(d, fw_domains, i915) {
+	for_each_fw_domain_masked(d, fw_domains, i915, tmp) {
 		fw_domain_wait_ack_clear(i915, d);
 		fw_domain_get(i915, d);
 	}
 
-	for_each_fw_domain_masked(d, fw_domains, i915)
+	for_each_fw_domain_masked(d, fw_domains, i915, tmp)
 		fw_domain_wait_ack(i915, d);
 
 	i915->uncore.fw_domains_active |= fw_domains;
@@ -134,8 +137,11 @@ static void
 fw_domains_put(struct drm_i915_private *i915, enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *d;
+	unsigned int tmp;
+
+	GEM_BUG_ON(fw_domains & ~i915->uncore.fw_domains);
 
-	for_each_fw_domain_masked(d, fw_domains, i915) {
+	for_each_fw_domain_masked(d, fw_domains, i915, tmp) {
 		fw_domain_put(i915, d);
 		fw_domain_posting_read(i915, d);
 	}
@@ -147,9 +153,10 @@ static void
 fw_domains_posting_read(struct drm_i915_private *i915)
 {
 	struct intel_uncore_forcewake_domain *d;
+	unsigned int tmp;
 
 	/* No need to do for all, just do for first found */
-	for_each_fw_domain(d, i915) {
+	for_each_fw_domain(d, i915, tmp) {
 		fw_domain_posting_read(i915, d);
 		break;
 	}
@@ -160,11 +167,14 @@ fw_domains_reset(struct drm_i915_private *i915,
 		 enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *d;
+	unsigned int tmp;
 
-	if (i915->uncore.fw_domains == 0)
+	if (!fw_domains)
 		return;
 
-	for_each_fw_domain_masked(d, fw_domains, i915)
+	GEM_BUG_ON(fw_domains & ~i915->uncore.fw_domains);
+
+	for_each_fw_domain_masked(d, fw_domains, i915, tmp)
 		fw_domain_reset(i915, d);
 
 	fw_domains_posting_read(i915);
@@ -274,9 +284,11 @@ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
 	 * timers are run before holding.
 	 */
 	while (1) {
+		unsigned int tmp;
+
 		active_domains = 0;
 
-		for_each_fw_domain(domain, dev_priv) {
+		for_each_fw_domain(domain, dev_priv, tmp) {
 			if (hrtimer_cancel(&domain->timer) == 0)
 				continue;
 
@@ -285,7 +297,7 @@ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
 
 		spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
 
-		for_each_fw_domain(domain, dev_priv) {
+		for_each_fw_domain(domain, dev_priv, tmp) {
 			if (hrtimer_active(&domain->timer))
 				active_domains |= domain->mask;
 		}
@@ -465,13 +477,13 @@ static void __intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,
 					 enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *domain;
+	unsigned int tmp;
 
 	fw_domains &= dev_priv->uncore.fw_domains;
 
-	for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
+	for_each_fw_domain_masked(domain, fw_domains, dev_priv, tmp)
 		if (domain->wake_count++)
 			fw_domains &= ~domain->mask;
-	}
 
 	if (fw_domains)
 		dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains);
@@ -528,10 +540,11 @@ static void __intel_uncore_forcewake_put(struct drm_i915_private *dev_priv,
 					 enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *domain;
+	unsigned int tmp;
 
 	fw_domains &= dev_priv->uncore.fw_domains;
 
-	for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
+	for_each_fw_domain_masked(domain, fw_domains, dev_priv, tmp) {
 		if (WARN_ON(domain->wake_count == 0))
 			continue;
 
@@ -936,8 +949,11 @@ static noinline void ___force_wake_auto(struct drm_i915_private *dev_priv,
 					enum forcewake_domains fw_domains)
 {
 	struct intel_uncore_forcewake_domain *domain;
+	unsigned int tmp;
+
+	GEM_BUG_ON(fw_domains & ~dev_priv->uncore.fw_domains);
 
-	for_each_fw_domain_masked(domain, fw_domains, dev_priv)
+	for_each_fw_domain_masked(domain, fw_domains, dev_priv, tmp)
 		fw_domain_arm_timer(domain);
 
 	dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains);
@@ -1175,7 +1191,7 @@ static void fw_domain_init(struct drm_i915_private *dev_priv,
 	BUILD_BUG_ON(FORCEWAKE_BLITTER != (1 << FW_DOMAIN_ID_BLITTER));
 	BUILD_BUG_ON(FORCEWAKE_MEDIA != (1 << FW_DOMAIN_ID_MEDIA));
 
-	d->mask = 1 << domain_id;
+	d->mask = BIT(domain_id);
 
 	hrtimer_init(&d->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	d->timer.function = intel_uncore_fw_release_timer;