Merge branch 'pm-domains'

Merge generlic power domains update for 5.19-rc1:

 - Extend dev_pm_domain_detach() doc (Krzysztof Kozlowski).

 - Move genpd's time-accounting to ktime_get_mono_fast_ns() (Ulf
   Hansson).

 - Improve the way genpd deals with its governors (Ulf Hansson).

* pm-domains:
  PM: domains: Trust domain-idle-states from DT to be correct by genpd
  PM: domains: Measure power-on/off latencies in genpd based on a governor
  PM: domains: Allocate governor data dynamically based on a genpd governor
  PM: domains: Clean up some code in pm_genpd_init() and genpd_remove()
  PM: domains: Fix initialization of genpd's next_wakeup
  PM: domains: Fixup QoS latency measurements for IRQ safe devices in genpd
  PM: domains: Measure suspend/resume latencies in genpd based on governor
  PM: domains: Move the next_wakeup variable into the struct gpd_timing_data
  PM: domains: Allocate gpd_timing_data dynamically based on governor
  PM: domains: Skip another warning in irq_safe_dev_in_sleep_domain()
  PM: domains: Rename irq_safe_dev_in_no_sleep_domain() in genpd
  PM: domains: Don't check PM_QOS_FLAG_NO_POWER_OFF in genpd
  PM: domains: Drop redundant code for genpd always-on governor
  PM: domains: Add GENPD_FLAG_RPM_ALWAYS_ON for the always-on governor
  PM: domains: Move genpd's time-accounting to ktime_get_mono_fast_ns()
  PM: domains: Extend dev_pm_domain_detach() doc

4 files changed, 223 insertions, 152 deletions

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index bbddb267c2e693..72115917e0bdde 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -172,10 +172,10 @@ EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
  * @dev: Device to detach.
  * @power_off: Used to indicate whether we should power off the device.
  *
- * This functions will reverse the actions from dev_pm_domain_attach() and
- * dev_pm_domain_attach_by_id(), thus it detaches @dev from its PM domain.
- * Typically it should be invoked during the remove phase, either from
- * subsystem level code or from drivers.
+ * This functions will reverse the actions from dev_pm_domain_attach(),
+ * dev_pm_domain_attach_by_id() and dev_pm_domain_attach_by_name(), thus it
+ * detaches @dev from its PM domain.  Typically it should be invoked during the
+ * remove phase, either from subsystem level code or from drivers.
  *
  * Callers must ensure proper synchronization of this function with power
  * management callbacks.
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 1ee878d126fdf5..739e52cd4aba5d 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -131,7 +131,7 @@ static const struct genpd_lock_ops genpd_spin_ops = {
 #define genpd_is_cpu_domain(genpd)	(genpd->flags & GENPD_FLAG_CPU_DOMAIN)
 #define genpd_is_rpm_always_on(genpd)	(genpd->flags & GENPD_FLAG_RPM_ALWAYS_ON)
 
-static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,
+static inline bool irq_safe_dev_in_sleep_domain(struct device *dev,
 		const struct generic_pm_domain *genpd)
 {
 	bool ret;
@@ -139,11 +139,14 @@ static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,
 	ret = pm_runtime_is_irq_safe(dev) && !genpd_is_irq_safe(genpd);
 
 	/*
-	 * Warn once if an IRQ safe device is attached to a no sleep domain, as
-	 * to indicate a suboptimal configuration for PM. For an always on
-	 * domain this isn't case, thus don't warn.
+	 * Warn once if an IRQ safe device is attached to a domain, which
+	 * callbacks are allowed to sleep. This indicates a suboptimal
+	 * configuration for PM, but it doesn't matter for an always on domain.
 	 */
-	if (ret && !genpd_is_always_on(genpd))
+	if (genpd_is_always_on(genpd) || genpd_is_rpm_always_on(genpd))
+		return ret;
+
+	if (ret)
 		dev_warn_once(dev, "PM domain %s will not be powered off\n",
 				genpd->name);
 
@@ -225,24 +228,23 @@ static void genpd_debug_remove(struct generic_pm_domain *genpd)
 
 static void genpd_update_accounting(struct generic_pm_domain *genpd)
 {
-	ktime_t delta, now;
+	u64 delta, now;
 
-	now = ktime_get();
-	delta = ktime_sub(now, genpd->accounting_time);
+	now = ktime_get_mono_fast_ns();
+	if (now <= genpd->accounting_time)
+		return;
+
+	delta = now - genpd->accounting_time;
 
 	/*
 	 * If genpd->status is active, it means we are just
 	 * out of off and so update the idle time and vice
 	 * versa.
 	 */
-	if (genpd->status == GENPD_STATE_ON) {
-		int state_idx = genpd->state_idx;
-
-		genpd->states[state_idx].idle_time =
-			ktime_add(genpd->states[state_idx].idle_time, delta);
-	} else {
-		genpd->on_time = ktime_add(genpd->on_time, delta);
-	}
+	if (genpd->status == GENPD_STATE_ON)
+		genpd->states[genpd->state_idx].idle_time += delta;
+	else
+		genpd->on_time += delta;
 
 	genpd->accounting_time = now;
 }
@@ -476,15 +478,16 @@ EXPORT_SYMBOL_GPL(dev_pm_genpd_set_performance_state);
  */
 void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next)
 {
-	struct generic_pm_domain_data *gpd_data;
 	struct generic_pm_domain *genpd;
+	struct gpd_timing_data *td;
 
 	genpd = dev_to_genpd_safe(dev);
 	if (!genpd)
 		return;
 
-	gpd_data = to_gpd_data(dev->power.subsys_data->domain_data);
-	gpd_data->next_wakeup = next;
+	td = to_gpd_data(dev->power.subsys_data->domain_data)->td;
+	if (td)
+		td->next_wakeup = next;
 }
 EXPORT_SYMBOL_GPL(dev_pm_genpd_set_next_wakeup);
 
@@ -506,6 +509,7 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
 	if (!genpd->power_on)
 		goto out;
 
+	timed = timed && genpd->gd && !genpd->states[state_idx].fwnode;
 	if (!timed) {
 		ret = genpd->power_on(genpd);
 		if (ret)
@@ -524,7 +528,7 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
 		goto out;
 
 	genpd->states[state_idx].power_on_latency_ns = elapsed_ns;
-	genpd->max_off_time_changed = true;
+	genpd->gd->max_off_time_changed = true;
 	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
 		 genpd->name, "on", elapsed_ns);
 
@@ -555,6 +559,7 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed)
 	if (!genpd->power_off)
 		goto out;
 
+	timed = timed && genpd->gd && !genpd->states[state_idx].fwnode;
 	if (!timed) {
 		ret = genpd->power_off(genpd);
 		if (ret)
@@ -573,7 +578,7 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed)
 		goto out;
 
 	genpd->states[state_idx].power_off_latency_ns = elapsed_ns;
-	genpd->max_off_time_changed = true;
+	genpd->gd->max_off_time_changed = true;
 	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
 		 genpd->name, "off", elapsed_ns);
 
@@ -649,18 +654,12 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 	}
 
 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
-		enum pm_qos_flags_status stat;
-
-		stat = dev_pm_qos_flags(pdd->dev, PM_QOS_FLAG_NO_POWER_OFF);
-		if (stat > PM_QOS_FLAGS_NONE)
-			return -EBUSY;
-
 		/*
 		 * Do not allow PM domain to be powered off, when an IRQ safe
 		 * device is part of a non-IRQ safe domain.
 		 */
 		if (!pm_runtime_suspended(pdd->dev) ||
-			irq_safe_dev_in_no_sleep_domain(pdd->dev, genpd))
+			irq_safe_dev_in_sleep_domain(pdd->dev, genpd))
 			not_suspended++;
 	}
 
@@ -775,25 +774,27 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 	dev = gpd_data->base.dev;
 
 	for (;;) {
-		struct generic_pm_domain *genpd;
+		struct generic_pm_domain *genpd = ERR_PTR(-ENODATA);
 		struct pm_domain_data *pdd;
+		struct gpd_timing_data *td;
 
 		spin_lock_irq(&dev->power.lock);
 
 		pdd = dev->power.subsys_data ?
 				dev->power.subsys_data->domain_data : NULL;
 		if (pdd) {
-			to_gpd_data(pdd)->td.constraint_changed = true;
-			genpd = dev_to_genpd(dev);
-		} else {
-			genpd = ERR_PTR(-ENODATA);
+			td = to_gpd_data(pdd)->td;
+			if (td) {
+				td->constraint_changed = true;
+				genpd = dev_to_genpd(dev);
+			}
 		}
 
 		spin_unlock_irq(&dev->power.lock);
 
 		if (!IS_ERR(genpd)) {
 			genpd_lock(genpd);
-			genpd->max_off_time_changed = true;
+			genpd->gd->max_off_time_changed = true;
 			genpd_unlock(genpd);
 		}
 
@@ -879,9 +880,9 @@ static int genpd_runtime_suspend(struct device *dev)
 	struct generic_pm_domain *genpd;
 	bool (*suspend_ok)(struct device *__dev);
 	struct generic_pm_domain_data *gpd_data = dev_gpd_data(dev);
-	struct gpd_timing_data *td = &gpd_data->td;
+	struct gpd_timing_data *td = gpd_data->td;
 	bool runtime_pm = pm_runtime_enabled(dev);
-	ktime_t time_start;
+	ktime_t time_start = 0;
 	s64 elapsed_ns;
 	int ret;
 
@@ -902,8 +903,7 @@ static int genpd_runtime_suspend(struct device *dev)
 		return -EBUSY;
 
 	/* Measure suspend latency. */
-	time_start = 0;
-	if (runtime_pm)
+	if (td && runtime_pm)
 		time_start = ktime_get();
 
 	ret = __genpd_runtime_suspend(dev);
@@ -917,13 +917,13 @@ static int genpd_runtime_suspend(struct device *dev)
 	}
 
 	/* Update suspend latency value if the measured time exceeds it. */
-	if (runtime_pm) {
+	if (td && runtime_pm) {
 		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
 		if (elapsed_ns > td->suspend_latency_ns) {
 			td->suspend_latency_ns = elapsed_ns;
 			dev_dbg(dev, "suspend latency exceeded, %lld ns\n",
 				elapsed_ns);
-			genpd->max_off_time_changed = true;
+			genpd->gd->max_off_time_changed = true;
 			td->constraint_changed = true;
 		}
 	}
@@ -932,7 +932,7 @@ static int genpd_runtime_suspend(struct device *dev)
 	 * If power.irq_safe is set, this routine may be run with
 	 * IRQs disabled, so suspend only if the PM domain also is irq_safe.
 	 */
-	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
+	if (irq_safe_dev_in_sleep_domain(dev, genpd))
 		return 0;
 
 	genpd_lock(genpd);
@@ -955,12 +955,11 @@ static int genpd_runtime_resume(struct device *dev)
 {
 	struct generic_pm_domain *genpd;
 	struct generic_pm_domain_data *gpd_data = dev_gpd_data(dev);
-	struct gpd_timing_data *td = &gpd_data->td;
-	bool runtime_pm = pm_runtime_enabled(dev);
-	ktime_t time_start;
+	struct gpd_timing_data *td = gpd_data->td;
+	bool timed = td && pm_runtime_enabled(dev);
+	ktime_t time_start = 0;
 	s64 elapsed_ns;
 	int ret;
-	bool timed = true;
 
 	dev_dbg(dev, "%s()\n", __func__);
 
@@ -972,10 +971,8 @@ static int genpd_runtime_resume(struct device *dev)
 	 * As we don't power off a non IRQ safe domain, which holds
 	 * an IRQ safe device, we don't need to restore power to it.
 	 */
-	if (irq_safe_dev_in_no_sleep_domain(dev, genpd)) {
-		timed = false;
+	if (irq_safe_dev_in_sleep_domain(dev, genpd))
 		goto out;
-	}
 
 	genpd_lock(genpd);
 	ret = genpd_power_on(genpd, 0);
@@ -988,8 +985,7 @@ static int genpd_runtime_resume(struct device *dev)
 
  out:
 	/* Measure resume latency. */
-	time_start = 0;
-	if (timed && runtime_pm)
+	if (timed)
 		time_start = ktime_get();
 
 	ret = genpd_start_dev(genpd, dev);
@@ -1001,13 +997,13 @@ static int genpd_runtime_resume(struct device *dev)
 		goto err_stop;
 
 	/* Update resume latency value if the measured time exceeds it. */
-	if (timed && runtime_pm) {
+	if (timed) {
 		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
 		if (elapsed_ns > td->resume_latency_ns) {
 			td->resume_latency_ns = elapsed_ns;
 			dev_dbg(dev, "resume latency exceeded, %lld ns\n",
 				elapsed_ns);
-			genpd->max_off_time_changed = true;
+			genpd->gd->max_off_time_changed = true;
 			td->constraint_changed = true;
 		}
 	}
@@ -1500,9 +1496,11 @@ EXPORT_SYMBOL_GPL(dev_pm_genpd_resume);
 
 #endif /* CONFIG_PM_SLEEP */
 
-static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev)
+static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
+							   bool has_governor)
 {
 	struct generic_pm_domain_data *gpd_data;
+	struct gpd_timing_data *td;
 	int ret;
 
 	ret = dev_pm_get_subsys_data(dev);
@@ -1516,26 +1514,38 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev)
 	}
 
 	gpd_data->base.dev = dev;
-	gpd_data->td.constraint_changed = true;
-	gpd_data->td.effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
 	gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier;
-	gpd_data->next_wakeup = KTIME_MAX;
 
-	spin_lock_irq(&dev->power.lock);
+	/* Allocate data used by a governor. */
+	if (has_governor) {
+		td = kzalloc(sizeof(*td), GFP_KERNEL);
+		if (!td) {
+			ret = -ENOMEM;
+			goto err_free;
+		}
 
-	if (dev->power.subsys_data->domain_data) {
-		ret = -EINVAL;
-		goto err_free;
+		td->constraint_changed = true;
+		td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
+		td->next_wakeup = KTIME_MAX;
+		gpd_data->td = td;
 	}
 
-	dev->power.subsys_data->domain_data = &gpd_data->base;
+	spin_lock_irq(&dev->power.lock);
+
+	if (dev->power.subsys_data->domain_data)
+		ret = -EINVAL;
+	else
+		dev->power.subsys_data->domain_data = &gpd_data->base;
 
 	spin_unlock_irq(&dev->power.lock);
 
+	if (ret)
+		goto err_free;
+
 	return gpd_data;
 
  err_free:
-	spin_unlock_irq(&dev->power.lock);
+	kfree(gpd_data->td);
 	kfree(gpd_data);
  err_put:
 	dev_pm_put_subsys_data(dev);
@@ -1551,6 +1561,7 @@ static void genpd_free_dev_data(struct device *dev,
 
 	spin_unlock_irq(&dev->power.lock);
 
+	kfree(gpd_data->td);
 	kfree(gpd_data);
 	dev_pm_put_subsys_data(dev);
 }
@@ -1607,6 +1618,7 @@ static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
 static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 			    struct device *base_dev)
 {
+	struct genpd_governor_data *gd = genpd->gd;
 	struct generic_pm_domain_data *gpd_data;
 	int ret;
 
@@ -1615,7 +1627,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev))
 		return -EINVAL;
 
-	gpd_data = genpd_alloc_dev_data(dev);
+	gpd_data = genpd_alloc_dev_data(dev, gd);
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
@@ -1631,7 +1643,8 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	dev_pm_domain_set(dev, &genpd->domain);
 
 	genpd->device_count++;
-	genpd->max_off_time_changed = true;
+	if (gd)
+		gd->max_off_time_changed = true;
 
 	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
 
@@ -1685,7 +1698,8 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
 	}
 
 	genpd->device_count--;
-	genpd->max_off_time_changed = true;
+	if (genpd->gd)
+		genpd->gd->max_off_time_changed = true;
 
 	genpd_clear_cpumask(genpd, gpd_data->cpu);
 	dev_pm_domain_set(dev, NULL);
@@ -1958,6 +1972,53 @@ static int genpd_set_default_power_state(struct generic_pm_domain *genpd)
 	return 0;
 }
 
+static int genpd_alloc_data(struct generic_pm_domain *genpd)
+{
+	struct genpd_governor_data *gd = NULL;
+	int ret;
+
+	if (genpd_is_cpu_domain(genpd) &&
+	    !zalloc_cpumask_var(&genpd->cpus, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (genpd->gov) {
+		gd = kzalloc(sizeof(*gd), GFP_KERNEL);
+		if (!gd) {
+			ret = -ENOMEM;
+			goto free;
+		}
+
+		gd->max_off_time_ns = -1;
+		gd->max_off_time_changed = true;
+		gd->next_wakeup = KTIME_MAX;
+	}
+
+	/* Use only one "off" state if there were no states declared */
+	if (genpd->state_count == 0) {
+		ret = genpd_set_default_power_state(genpd);
+		if (ret)
+			goto free;
+	}
+
+	genpd->gd = gd;
+	return 0;
+
+free:
+	if (genpd_is_cpu_domain(genpd))
+		free_cpumask_var(genpd->cpus);
+	kfree(gd);
+	return ret;
+}
+
+static void genpd_free_data(struct generic_pm_domain *genpd)
+{
+	if (genpd_is_cpu_domain(genpd))
+		free_cpumask_var(genpd->cpus);
+	if (genpd->free_states)
+		genpd->free_states(genpd->states, genpd->state_count);
+	kfree(genpd->gd);
+}
+
 static void genpd_lock_init(struct generic_pm_domain *genpd)
 {
 	if (genpd->flags & GENPD_FLAG_IRQ_SAFE) {
@@ -1995,11 +2056,9 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 	atomic_set(&genpd->sd_count, 0);
 	genpd->status = is_off ? GENPD_STATE_OFF : GENPD_STATE_ON;
 	genpd->device_count = 0;
-	genpd->max_off_time_ns = -1;
-	genpd->max_off_time_changed = true;
 	genpd->provider = NULL;
 	genpd->has_provider = false;
-	genpd->accounting_time = ktime_get();
+	genpd->accounting_time = ktime_get_mono_fast_ns();
 	genpd->domain.ops.runtime_suspend = genpd_runtime_suspend;
 	genpd->domain.ops.runtime_resume = genpd_runtime_resume;
 	genpd->domain.ops.prepare = genpd_prepare;
@@ -2017,26 +2076,22 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 		genpd->dev_ops.start = pm_clk_resume;
 	}
 
+	/* The always-on governor works better with the corresponding flag. */
+	if (gov == &pm_domain_always_on_gov)
+		genpd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
+
 	/* Always-on domains must be powered on at initialization. */
 	if ((genpd_is_always_on(genpd) || genpd_is_rpm_always_on(genpd)) &&
 			!genpd_status_on(genpd))
 		return -EINVAL;
 
-	if (genpd_is_cpu_domain(genpd) &&
-	    !zalloc_cpumask_var(&genpd->cpus, GFP_KERNEL))
-		return -ENOMEM;
-
-	/* Use only one "off" state if there were no states declared */
-	if (genpd->state_count == 0) {
-		ret = genpd_set_default_power_state(genpd);
-		if (ret) {
-			if (genpd_is_cpu_domain(genpd))
-				free_cpumask_var(genpd->cpus);
-			return ret;
-		}
-	} else if (!gov && genpd->state_count > 1) {
+	/* Multiple states but no governor doesn't make sense. */
+	if (!gov && genpd->state_count > 1)
 		pr_warn("%s: no governor for states\n", genpd->name);
-	}
+
+	ret = genpd_alloc_data(genpd);
+	if (ret)
+		return ret;
 
 	device_initialize(&genpd->dev);
 	dev_set_name(&genpd->dev, "%s", genpd->name);
@@ -2081,10 +2136,7 @@ static int genpd_remove(struct generic_pm_domain *genpd)
 	genpd_unlock(genpd);
 	genpd_debug_remove(genpd);
 	cancel_work_sync(&genpd->power_off_work);
-	if (genpd_is_cpu_domain(genpd))
-		free_cpumask_var(genpd->cpus);
-	if (genpd->free_states)
-		genpd->free_states(genpd->states, genpd->state_count);
+	genpd_free_data(genpd);
 
 	pr_debug("%s: removed %s\n", __func__, genpd->name);
 
@@ -3163,6 +3215,7 @@ static int sub_domains_show(struct seq_file *s, void *data)
 static int idle_states_show(struct seq_file *s, void *data)
 {
 	struct generic_pm_domain *genpd = s->private;
+	u64 now, delta, idle_time = 0;
 	unsigned int i;
 	int ret = 0;
 
@@ -3173,17 +3226,19 @@ static int idle_states_show(struct seq_file *s, void *data)
 	seq_puts(s, "State          Time Spent(ms) Usage          Rejected\n");
 
 	for (i = 0; i < genpd->state_count; i++) {
-		ktime_t delta = 0;
-		s64 msecs;
+		idle_time += genpd->states[i].idle_time;
 
-		if ((genpd->status == GENPD_STATE_OFF) &&
-				(genpd->state_idx == i))
-			delta = ktime_sub(ktime_get(), genpd->accounting_time);
+		if (genpd->status == GENPD_STATE_OFF && genpd->state_idx == i) {
+			now = ktime_get_mono_fast_ns();
+			if (now > genpd->accounting_time) {
+				delta = now - genpd->accounting_time;
+				idle_time += delta;
+			}
+		}
 
-		msecs = ktime_to_ms(
-			ktime_add(genpd->states[i].idle_time, delta));
-		seq_printf(s, "S%-13i %-14lld %-14llu %llu\n", i, msecs,
-			      genpd->states[i].usage, genpd->states[i].rejected);
+		do_div(idle_time, NSEC_PER_MSEC);
+		seq_printf(s, "S%-13i %-14llu %-14llu %llu\n", i, idle_time,
+			   genpd->states[i].usage, genpd->states[i].rejected);
 	}
 
 	genpd_unlock(genpd);
@@ -3193,18 +3248,22 @@ static int idle_states_show(struct seq_file *s, void *data)
 static int active_time_show(struct seq_file *s, void *data)
 {
 	struct generic_pm_domain *genpd = s->private;
-	ktime_t delta = 0;
+	u64 now, on_time, delta = 0;
 	int ret = 0;
 
 	ret = genpd_lock_interruptible(genpd);
 	if (ret)
 		return -ERESTARTSYS;
 
-	if (genpd->status == GENPD_STATE_ON)
-		delta = ktime_sub(ktime_get(), genpd->accounting_time);
+	if (genpd->status == GENPD_STATE_ON) {
+		now = ktime_get_mono_fast_ns();
+		if (now > genpd->accounting_time)
+			delta = now - genpd->accounting_time;
+	}
 
-	seq_printf(s, "%lld ms\n", ktime_to_ms(
-				ktime_add(genpd->on_time, delta)));
+	on_time = genpd->on_time + delta;
+	do_div(on_time, NSEC_PER_MSEC);
+	seq_printf(s, "%llu ms\n", on_time);
 
 	genpd_unlock(genpd);
 	return ret;
@@ -3213,7 +3272,7 @@ static int active_time_show(struct seq_file *s, void *data)
 static int total_idle_time_show(struct seq_file *s, void *data)
 {
 	struct generic_pm_domain *genpd = s->private;
-	ktime_t delta = 0, total = 0;
+	u64 now, delta, total = 0;
 	unsigned int i;
 	int ret = 0;
 
@@ -3222,16 +3281,19 @@ static int total_idle_time_show(struct seq_file *s, void *data)
 		return -ERESTARTSYS;
 
 	for (i = 0; i < genpd->state_count; i++) {
+		total += genpd->states[i].idle_time;
 
-		if ((genpd->status == GENPD_STATE_OFF) &&
-				(genpd->state_idx == i))
-			delta = ktime_sub(ktime_get(), genpd->accounting_time);
-
-		total = ktime_add(total, genpd->states[i].idle_time);
+		if (genpd->status == GENPD_STATE_OFF && genpd->state_idx == i) {
+			now = ktime_get_mono_fast_ns();
+			if (now > genpd->accounting_time) {
+				delta = now - genpd->accounting_time;
+				total += delta;
+			}
+		}
 	}
-	total = ktime_add(total, delta);
 
-	seq_printf(s, "%lld ms\n", ktime_to_ms(total));
+	do_div(total, NSEC_PER_MSEC);
+	seq_printf(s, "%llu ms\n", total);
 
 	genpd_unlock(genpd);
 	return ret;
diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
index cd08c588519057..282a3a135827ce 100644
--- a/drivers/base/power/domain_governor.c
+++ b/drivers/base/power/domain_governor.c
@@ -18,6 +18,8 @@ static int dev_update_qos_constraint(struct device *dev, void *data)
 	s64 constraint_ns;
 
 	if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {
+		struct gpd_timing_data *td = dev_gpd_data(dev)->td;
+
 		/*
 		 * Only take suspend-time QoS constraints of devices into
 		 * account, because constraints updated after the device has
@@ -25,7 +27,8 @@ static int dev_update_qos_constraint(struct device *dev, void *data)
 		 * anyway.  In order for them to take effect, the device has to
 		 * be resumed and suspended again.
 		 */
-		constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns;
+		constraint_ns = td ? td->effective_constraint_ns :
+				PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
 	} else {
 		/*
 		 * The child is not in a domain and there's no info on its
@@ -49,7 +52,7 @@ static int dev_update_qos_constraint(struct device *dev, void *data)
  */
 static bool default_suspend_ok(struct device *dev)
 {
-	struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+	struct gpd_timing_data *td = dev_gpd_data(dev)->td;
 	unsigned long flags;
 	s64 constraint_ns;
 
@@ -136,26 +139,28 @@ static void update_domain_next_wakeup(struct generic_pm_domain *genpd, ktime_t n
 	 * is able to enter its optimal idle state.
 	 */
 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
-		next_wakeup = to_gpd_data(pdd)->next_wakeup;
+		next_wakeup = to_gpd_data(pdd)->td->next_wakeup;
 		if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
 			if (ktime_before(next_wakeup, domain_wakeup))
 				domain_wakeup = next_wakeup;
 	}
 
 	list_for_each_entry(link, &genpd->parent_links, parent_node) {
-		next_wakeup = link->child->next_wakeup;
+		struct genpd_governor_data *cgd = link->child->gd;
+
+		next_wakeup = cgd ? cgd->next_wakeup : KTIME_MAX;
 		if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
 			if (ktime_before(next_wakeup, domain_wakeup))
 				domain_wakeup = next_wakeup;
 	}
 
-	genpd->next_wakeup = domain_wakeup;
+	genpd->gd->next_wakeup = domain_wakeup;
 }
 
 static bool next_wakeup_allows_state(struct generic_pm_domain *genpd,
 				     unsigned int state, ktime_t now)
 {
-	ktime_t domain_wakeup = genpd->next_wakeup;
+	ktime_t domain_wakeup = genpd->gd->next_wakeup;
 	s64 idle_time_ns, min_sleep_ns;
 
 	min_sleep_ns = genpd->states[state].power_off_latency_ns +
@@ -185,8 +190,9 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
 	 * All subdomains have been powered off already at this point.
 	 */
 	list_for_each_entry(link, &genpd->parent_links, parent_node) {
-		struct generic_pm_domain *sd = link->child;
-		s64 sd_max_off_ns = sd->max_off_time_ns;
+		struct genpd_governor_data *cgd = link->child->gd;
+
+		s64 sd_max_off_ns = cgd ? cgd->max_off_time_ns : -1;
 
 		if (sd_max_off_ns < 0)
 			continue;
@@ -215,7 +221,7 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
 		 * domain to turn off and on (that's how much time it will
 		 * have to wait worst case).
 		 */
-		td = &to_gpd_data(pdd)->td;
+		td = to_gpd_data(pdd)->td;
 		constraint_ns = td->effective_constraint_ns;
 		/*
 		 * Zero means "no suspend at all" and this runs only when all
@@ -244,7 +250,7 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
 	 * time and the time needed to turn the domain on is the maximum
 	 * theoretical time this domain can spend in the "off" state.
 	 */
-	genpd->max_off_time_ns = min_off_time_ns -
+	genpd->gd->max_off_time_ns = min_off_time_ns -
 		genpd->states[state].power_on_latency_ns;
 	return true;
 }
@@ -259,6 +265,7 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
 static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 {
 	struct generic_pm_domain *genpd = pd_to_genpd(pd);
+	struct genpd_governor_data *gd = genpd->gd;
 	int state_idx = genpd->state_count - 1;
 	struct gpd_link *link;
 
@@ -269,11 +276,11 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 	 * cannot be met.
 	 */
 	update_domain_next_wakeup(genpd, now);
-	if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (genpd->next_wakeup != KTIME_MAX)) {
+	if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (gd->next_wakeup != KTIME_MAX)) {
 		/* Let's find out the deepest domain idle state, the devices prefer */
 		while (state_idx >= 0) {
 			if (next_wakeup_allows_state(genpd, state_idx, now)) {
-				genpd->max_off_time_changed = true;
+				gd->max_off_time_changed = true;
 				break;
 			}
 			state_idx--;
@@ -281,14 +288,14 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 
 		if (state_idx < 0) {
 			state_idx = 0;
-			genpd->cached_power_down_ok = false;
+			gd->cached_power_down_ok = false;
 			goto done;
 		}
 	}
 
-	if (!genpd->max_off_time_changed) {
-		genpd->state_idx = genpd->cached_power_down_state_idx;
-		return genpd->cached_power_down_ok;
+	if (!gd->max_off_time_changed) {
+		genpd->state_idx = gd->cached_power_down_state_idx;
+		return gd->cached_power_down_ok;
 	}
 
 	/*
@@ -297,12 +304,16 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 	 * going to be called for any parent until this instance
 	 * returns.
 	 */
-	list_for_each_entry(link, &genpd->child_links, child_node)
-		link->parent->max_off_time_changed = true;
+	list_for_each_entry(link, &genpd->child_links, child_node) {
+		struct genpd_governor_data *pgd = link->parent->gd;
+
+		if (pgd)
+			pgd->max_off_time_changed = true;
+	}
 
-	genpd->max_off_time_ns = -1;
-	genpd->max_off_time_changed = false;
-	genpd->cached_power_down_ok = true;
+	gd->max_off_time_ns = -1;
+	gd->max_off_time_changed = false;
+	gd->cached_power_down_ok = true;
 
 	/*
 	 * Find a state to power down to, starting from the state
@@ -310,7 +321,7 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 	 */
 	while (!__default_power_down_ok(pd, state_idx)) {
 		if (state_idx == 0) {
-			genpd->cached_power_down_ok = false;
+			gd->cached_power_down_ok = false;
 			break;
 		}
 		state_idx--;
@@ -318,8 +329,8 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
 
 done:
 	genpd->state_idx = state_idx;
-	genpd->cached_power_down_state_idx = genpd->state_idx;
-	return genpd->cached_power_down_ok;
+	gd->cached_power_down_state_idx = genpd->state_idx;
+	return gd->cached_power_down_ok;
 }
 
 static bool default_power_down_ok(struct dev_pm_domain *pd)
@@ -327,11 +338,6 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
 	return _default_power_down_ok(pd, ktime_get());
 }
 
-static bool always_on_power_down_ok(struct dev_pm_domain *domain)
-{
-	return false;
-}
-
 #ifdef CONFIG_CPU_IDLE
 static bool cpu_power_down_ok(struct dev_pm_domain *pd)
 {
@@ -401,6 +407,5 @@ struct dev_power_governor simple_qos_governor = {
  * pm_genpd_gov_always_on - A governor implementing an always-on policy
  */
 struct dev_power_governor pm_domain_always_on_gov = {
-	.power_down_ok = always_on_power_down_ok,
 	.suspend_ok = default_suspend_ok,
 };
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 67017c9390c878..ebc3516980907e 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -91,6 +91,14 @@ struct gpd_dev_ops {
 	int (*stop)(struct device *dev);
 };
 
+struct genpd_governor_data {
+	s64 max_off_time_ns;
+	bool max_off_time_changed;
+	ktime_t next_wakeup;
+	bool cached_power_down_ok;
+	bool cached_power_down_state_idx;
+};
+
 struct genpd_power_state {
 	s64 power_off_latency_ns;
 	s64 power_on_latency_ns;
@@ -98,7 +106,7 @@ struct genpd_power_state {
 	u64 usage;
 	u64 rejected;
 	struct fwnode_handle *fwnode;
-	ktime_t idle_time;
+	u64 idle_time;
 	void *data;
 };
 
@@ -114,6 +122,7 @@ struct generic_pm_domain {
 	struct list_head child_links;	/* Links with PM domain as a child */
 	struct list_head dev_list;	/* List of devices */
 	struct dev_power_governor *gov;
+	struct genpd_governor_data *gd;	/* Data used by a genpd governor. */
 	struct work_struct power_off_work;
 	struct fwnode_handle *provider;	/* Identity of the domain provider */
 	bool has_provider;
@@ -134,11 +143,6 @@ struct generic_pm_domain {
 	int (*set_performance_state)(struct generic_pm_domain *genpd,
 				     unsigned int state);
 	struct gpd_dev_ops dev_ops;
-	s64 max_off_time_ns;	/* Maximum allowed "suspended" time. */
-	ktime_t next_wakeup;	/* Maintained by the domain governor */
-	bool max_off_time_changed;
-	bool cached_power_down_ok;
-	bool cached_power_down_state_idx;
 	int (*attach_dev)(struct generic_pm_domain *domain,
 			  struct device *dev);
 	void (*detach_dev)(struct generic_pm_domain *domain,
@@ -149,8 +153,8 @@ struct generic_pm_domain {
 			    unsigned int state_count);
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
-	ktime_t on_time;
-	ktime_t accounting_time;
+	u64 on_time;
+	u64 accounting_time;
 	const struct genpd_lock_ops *lock_ops;
 	union {
 		struct mutex mlock;
@@ -182,6 +186,7 @@ struct gpd_timing_data {
 	s64 suspend_latency_ns;
 	s64 resume_latency_ns;
 	s64 effective_constraint_ns;
+	ktime_t	next_wakeup;
 	bool constraint_changed;
 	bool cached_suspend_ok;
 };
@@ -193,14 +198,13 @@ struct pm_domain_data {
 
 struct generic_pm_domain_data {
 	struct pm_domain_data base;
-	struct gpd_timing_data td;
+	struct gpd_timing_data *td;
 	struct notifier_block nb;
 	struct notifier_block *power_nb;
 	int cpu;
 	unsigned int performance_state;
 	unsigned int default_pstate;
 	unsigned int rpm_pstate;
-	ktime_t	next_wakeup;
 	void *data;
 };