diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 8ba6625..bde6141 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -607,7 +607,16 @@ individually.  Instead, a set of devices sharing a power resource can be put
 into a low-power state together at the same time by turning off the shared
 power resource.  Of course, they also need to be put into the full-power state
 together, by turning the shared power resource on.  A set of devices with this
-property is often referred to as a power domain.
+property is often referred to as a power domain. A power domain may also be
+nested inside another power domain.
+
+Devices, by default, operate in process context and if a device can operate in
+IRQ safe context, has to be explicitly set as IRQ safe. Power domains by
+default, operate in process context but could have devices that are IRQ safe.
+Such power domains cannot be powered on/off during runtime PM. On the other
+hand, an IRQ safe PM domain that can be powered on/off and suspended or resumed
+in an atomic context, may contain IRQ safe devices. Such domains may only
+contain IRQ safe devices or IRQ safe sub-domains.
 
 Support for power domains is provided through the pm_domain field of struct
 device.  This field is a pointer to an object of type struct dev_pm_domain,
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index abc81bd..8df43f8 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -44,6 +44,80 @@ static int pm_genpd_alloc_states_names(struct generic_pm_domain *genpd,
 static LIST_HEAD(gpd_list);
 static DEFINE_MUTEX(gpd_list_lock);
 
+static inline int genpd_lock_nosleep(struct generic_pm_domain *genpd,
+					unsigned int subclass)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	if (subclass > 0)
+		spin_lock_irqsave_nested(&genpd->slock, flags, subclass);
+	else
+		spin_lock_irqsave(&genpd->slock, flags);
+
+	genpd->lock_flags = flags;
+	return 0;
+}
+
+static inline void genpd_unlock_nosleep(struct generic_pm_domain *genpd)
+	__releases(&genpd->slock)
+{
+	spin_unlock_irqrestore(&genpd->slock, genpd->lock_flags);
+}
+
+static inline int genpd_lock_irq(struct generic_pm_domain *genpd,
+					unsigned int subclass)
+	__acquires(&genpd->mlock)
+{
+	if (subclass > 0)
+		mutex_lock_nested(&genpd->mlock, subclass);
+	else
+		mutex_lock(&genpd->mlock);
+	return 0;
+}
+
+static inline int genpd_lock_interruptible_irq(struct generic_pm_domain *genpd)
+	__acquires(&genpd->mlock)
+{
+	return mutex_lock_interruptible(&genpd->mlock);
+}
+
+static inline void genpd_unlock_irq(struct generic_pm_domain *genpd)
+	__releases(&genpd->mlock)
+{
+	mutex_unlock(&genpd->mlock);
+}
+
+static inline int genpd_lock(struct generic_pm_domain *genpd)
+{
+	return genpd->irq_safe ? genpd_lock_nosleep(genpd, 0)
+			: genpd_lock_irq(genpd, 0);
+}
+
+static inline int genpd_lock_nested(struct generic_pm_domain *genpd)
+{
+	return genpd->irq_safe ? genpd_lock_nosleep(genpd, SINGLE_DEPTH_NESTING)
+			: genpd_lock_irq(genpd, SINGLE_DEPTH_NESTING);
+}
+
+static inline int genpd_lock_interruptible(struct generic_pm_domain *genpd)
+{
+	return genpd->irq_safe ? genpd_lock_nosleep(genpd, 0)
+			: genpd_lock_interruptible_irq(genpd);
+}
+
+static inline void genpd_unlock(struct generic_pm_domain *genpd)
+{
+	return genpd->irq_safe ? genpd_unlock_nosleep(genpd)
+			: genpd_unlock_irq(genpd);
+}
+
+static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,
+		struct generic_pm_domain *genpd)
+{
+	return dev->power.irq_safe && !genpd->irq_safe;
+}
+
 /*
  * Get the generic PM domain for a particular struct device.
  * This validates the struct device pointer, the PM domain pointer,
@@ -238,9 +312,9 @@ static int genpd_poweron(struct generic_pm_domain *genpd)
 {
 	int ret;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	ret = __genpd_poweron(genpd);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 	return ret;
 }
 
@@ -282,9 +356,9 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 		spin_unlock_irq(&dev->power.lock);
 
 		if (!IS_ERR(genpd)) {
-			mutex_lock(&genpd->lock);
+			genpd_lock(genpd);
 			genpd->max_off_time_changed = true;
-			mutex_unlock(&genpd->lock);
+			genpd_unlock(genpd);
 		}
 
 		dev = dev->parent;
@@ -330,8 +404,17 @@ static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async)
 		if (stat > PM_QOS_FLAGS_NONE)
 			return -EBUSY;
 
-		if (!pm_runtime_suspended(pdd->dev) || pdd->dev->power.irq_safe)
+		/*
+		 * We do not want to power off the domain if the device is
+		 * not suspended or an IRQ safe device is part of this
+		 * non-IRQ safe domain.
+		 */
+		if (!pm_runtime_suspended(pdd->dev) ||
+			irq_safe_dev_in_no_sleep_domain(pdd->dev, genpd))
 			not_suspended++;
+		WARN_ONCE(irq_safe_dev_in_no_sleep_domain(pdd->dev, genpd),
+				"PM domain %s will not be powered off\n",
+				genpd->name);
 	}
 
 	if (not_suspended > 1 || (not_suspended == 1 && is_async))
@@ -381,9 +464,9 @@ static void genpd_power_off_work_fn(struct work_struct *work)
 
 	genpd = container_of(work, struct generic_pm_domain, power_off_work);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, true);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 }
 
 /**
@@ -437,15 +520,18 @@ static int pm_genpd_runtime_suspend(struct device *dev)
 	}
 
 	/*
-	 * If power.irq_safe is set, this routine will be run with interrupts
-	 * off, so it can't use mutexes.
+	 * If power.irq_safe is set, this routine may be run with
+	 * IRQ disabled, so suspend only if the power domain is
+	 * irq_safe.
 	 */
-	if (dev->power.irq_safe)
+	WARN_ONCE(irq_safe_dev_in_no_sleep_domain(dev, genpd),
+			"genpd %s will not be powered off\n", genpd->name);
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
 		return 0;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, false);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
@@ -473,15 +559,18 @@ static int pm_genpd_runtime_resume(struct device *dev)
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	/* If power.irq_safe, the PM domain is never powered off. */
-	if (dev->power.irq_safe) {
+	/*
+	 * As we dont power off a non IRQ safe domain, which holds
+	 * an IRQ safe device, we dont need to restore power to it.
+	 */
+	if (dev->power.irq_safe && !genpd->irq_safe) {
 		timed = false;
 		goto out;
 	}
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	ret = __genpd_poweron(genpd);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		return ret;
@@ -695,14 +784,14 @@ static int pm_genpd_prepare(struct device *dev)
 	if (resume_needed(dev, genpd))
 		pm_runtime_resume(dev);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count++ == 0) {
 		genpd->suspended_count = 0;
 		genpd->suspend_power_off = genpd->status == GPD_STATE_POWER_OFF;
 	}
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (genpd->suspend_power_off) {
 		pm_runtime_put_noidle(dev);
@@ -720,12 +809,12 @@ static int pm_genpd_prepare(struct device *dev)
 
 	ret = pm_generic_prepare(dev);
 	if (ret) {
-		mutex_lock(&genpd->lock);
+		genpd_lock(genpd);
 
 		if (--genpd->prepared_count == 0)
 			genpd->suspend_power_off = false;
 
-		mutex_unlock(&genpd->lock);
+		genpd_unlock(genpd);
 		pm_runtime_enable(dev);
 	}
 
@@ -1083,13 +1172,13 @@ static void pm_genpd_complete(struct device *dev)
 	if (IS_ERR(genpd))
 		return;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	run_complete = !genpd->suspend_power_off;
 	if (--genpd->prepared_count == 0)
 		genpd->suspend_power_off = false;
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (run_complete) {
 		pm_generic_complete(dev);
@@ -1275,11 +1364,18 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev))
 		return -EINVAL;
 
+	if (genpd->irq_safe && !dev->power.irq_safe) {
+		dev_err(dev,
+			"PM Domain %s is IRQ safe; device has to IRQ safe.\n",
+			genpd->name);
+		return -EINVAL;
+	}
+
 	gpd_data = genpd_alloc_dev_data(dev, genpd, td);
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1296,7 +1392,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		genpd_free_dev_data(dev, gpd_data);
@@ -1328,7 +1424,7 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	gpd_data = to_gpd_data(pdd);
 	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1343,14 +1439,14 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 
 	list_del_init(&pdd->list_node);
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	genpd_free_dev_data(dev, gpd_data);
 
 	return 0;
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 	dev_pm_qos_add_notifier(dev, &gpd_data->nb);
 
 	return ret;
@@ -1371,12 +1467,23 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 	    || genpd == subdomain)
 		return -EINVAL;
 
+	/*
+	 * If the domain can be powered on/off in an IRQ safe
+	 * context, ensure that the subdomain can also be
+	 * powered on/off in that context.
+	 */
+	if (genpd->irq_safe && !subdomain->irq_safe) {
+		WARN("Sub-domain (%s) in an IRQ-safe domain (%s) has to be IRQ safe\n",
+				subdomain->name, genpd->name);
+		return -EINVAL;
+	}
+
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
 	if (!link)
 		return -ENOMEM;
 
-	mutex_lock(&genpd->lock);
-	mutex_lock_nested(&subdomain->lock, SINGLE_DEPTH_NESTING);
+	genpd_lock(genpd);
+	genpd_lock_nested(subdomain);
 
 	if (genpd->status == GPD_STATE_POWER_OFF
 	    &&  subdomain->status != GPD_STATE_POWER_OFF) {
@@ -1399,8 +1506,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 		genpd_sd_counter_inc(genpd);
 
  out:
-	mutex_unlock(&subdomain->lock);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(subdomain);
+	genpd_unlock(genpd);
 	if (ret)
 		kfree(link);
 	return ret;
@@ -1421,7 +1528,7 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain))
 		return -EINVAL;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (!list_empty(&subdomain->slave_links) || subdomain->device_count) {
 		pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
@@ -1434,7 +1541,7 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 		if (link->slave != subdomain)
 			continue;
 
-		mutex_lock_nested(&subdomain->lock, SINGLE_DEPTH_NESTING);
+		genpd_lock_nested(subdomain);
 
 		list_del(&link->master_node);
 		list_del(&link->slave_node);
@@ -1442,14 +1549,14 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 		if (subdomain->status != GPD_STATE_POWER_OFF)
 			genpd_sd_counter_dec(genpd);
 
-		mutex_unlock(&subdomain->lock);
+		genpd_unlock(subdomain);
 
 		ret = 0;
 		break;
 	}
 
 out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return ret;
 }
@@ -1612,6 +1719,17 @@ static int of_genpd_device_parse_states(struct device_node *np,
 	return err;
 }
 
+static void genpd_lock_init(struct generic_pm_domain *genpd)
+{
+	if (genpd->flags & GENPD_FLAG_IRQ_SAFE) {
+		spin_lock_init(&genpd->slock);
+		genpd->irq_safe = true;
+	} else {
+		mutex_init(&genpd->mlock);
+		genpd->irq_safe = false;
+	}
+}
+
 /**
  * pm_genpd_init - Initialize a generic I/O PM domain object.
  * @genpd: PM domain object to initialize.
@@ -1636,7 +1754,7 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
 	INIT_LIST_HEAD(&genpd->master_links);
 	INIT_LIST_HEAD(&genpd->slave_links);
 	INIT_LIST_HEAD(&genpd->dev_list);
-	mutex_init(&genpd->lock);
+	genpd_lock_init(genpd);
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
 	atomic_set(&genpd->sd_count, 0);
@@ -2100,7 +2218,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	struct gpd_link *link;
 	int ret;
 
-	ret = mutex_lock_interruptible(&genpd->lock);
+	ret = genpd_lock_interruptible(genpd);
 	if (ret)
 		return -ERESTARTSYS;
 
@@ -2124,7 +2242,8 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	}
 
 	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
-		kobj_path = kobject_get_path(&pm_data->dev->kobj, GFP_KERNEL);
+		kobj_path = kobject_get_path(&pm_data->dev->kobj,
+				genpd->irq_safe ? GFP_ATOMIC : GFP_KERNEL);
 		if (kobj_path == NULL)
 			continue;
 
@@ -2135,7 +2254,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 
 	seq_puts(s, "\n");
 exit:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index fed024a..f1329ea 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -15,9 +15,11 @@
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/notifier.h>
+#include <linux/spinlock.h>
 
 /* Defines used for the flags field in the struct generic_pm_domain */
 #define GENPD_FLAG_PM_CLK	(1U << 0) /* PM domain uses PM clk */
+#define GENPD_FLAG_IRQ_SAFE	(1U << 1) /* PM domain operates in atomic */
 
 enum gpd_status {
 	GPD_STATE_ACTIVE = 0,	/* PM domain is active */
@@ -51,7 +53,6 @@ struct generic_pm_domain {
 	struct list_head master_links;	/* Links with PM domain as a master */
 	struct list_head slave_links;	/* Links with PM domain as a slave */
 	struct list_head dev_list;	/* List of devices */
-	struct mutex lock;
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
 	const char *name;
@@ -75,7 +76,14 @@ struct generic_pm_domain {
 	struct genpd_power_state *states;
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
-
+	bool irq_safe;
+	union {
+		struct mutex mlock;
+		struct {
+			spinlock_t slock;
+			unsigned long lock_flags;
+		};
+	};
 };
 
 static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
