diff --git a/Documentation/IRQ-domain.txt b/Documentation/IRQ-domain.txt
index 8a8b82c9ca53..39cfa72732ff 100644
--- a/Documentation/IRQ-domain.txt
+++ b/Documentation/IRQ-domain.txt
@@ -151,3 +151,74 @@ used and no descriptor gets allocated it is very important to make sure
 that the driver using the simple domain call irq_create_mapping()
 before any irq_find_mapping() since the latter will actually work
 for the static IRQ assignment case.
+
+==== Hierarchy IRQ domain ====
+On some architectures, there may be multiple interrupt controllers
+involved in delivering an interrupt from the device to the target CPU.
+Let's look at a typical interrupt delivering path on x86 platforms:
+
+Device --> IOAPIC -> Interrupt remapping Controller -> Local APIC -> CPU
+
+There are three interrupt controllers involved:
+1) IOAPIC controller
+2) Interrupt remapping controller
+3) Local APIC controller
+
+To support such a hardware topology and make software architecture match
+hardware architecture, an irq_domain data structure is built for each
+interrupt controller and those irq_domains are organized into hierarchy.
+When building irq_domain hierarchy, the irq_domain near to the device is
+child and the irq_domain near to CPU is parent. So a hierarchy structure
+as below will be built for the example above.
+	CPU Vector irq_domain (root irq_domain to manage CPU vectors)
+		^
+		|
+	Interrupt Remapping irq_domain (manage irq_remapping entries)
+		^
+		|
+	IOAPIC irq_domain (manage IOAPIC delivery entries/pins)
+
+There are four major interfaces to use hierarchy irq_domain:
+1) irq_domain_alloc_irqs(): allocate IRQ descriptors and interrupt
+   controller related resources to deliver these interrupts.
+2) irq_domain_free_irqs(): free IRQ descriptors and interrupt controller
+   related resources associated with these interrupts.
+3) irq_domain_activate_irq(): activate interrupt controller hardware to
+   deliver the interrupt.
+3) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
+   to stop delivering the interrupt.
+
+Following changes are needed to support hierarchy irq_domain.
+1) a new field 'parent' is added to struct irq_domain; it's used to
+   maintain irq_domain hierarchy information.
+2) a new field 'parent_data' is added to struct irq_data; it's used to
+   build hierarchy irq_data to match hierarchy irq_domains. The irq_data
+   is used to store irq_domain pointer and hardware irq number.
+3) new callbacks are added to struct irq_domain_ops to support hierarchy
+   irq_domain operations.
+
+With support of hierarchy irq_domain and hierarchy irq_data ready, an
+irq_domain structure is built for each interrupt controller, and an
+irq_data structure is allocated for each irq_domain associated with an
+IRQ. Now we could go one step further to support stacked(hierarchy)
+irq_chip. That is, an irq_chip is associated with each irq_data along
+the hierarchy. A child irq_chip may implement a required action by
+itself or by cooperating with its parent irq_chip.
+
+With stacked irq_chip, interrupt controller driver only needs to deal
+with the hardware managed by itself and may ask for services from its
+parent irq_chip when needed. So we could achieve a much cleaner
+software architecture.
+
+For an interrupt controller driver to support hierarchy irq_domain, it
+needs to:
+1) Implement irq_domain_ops.alloc and irq_domain_ops.free
+2) Optionally implement irq_domain_ops.activate and
+   irq_domain_ops.deactivate.
+3) Optionally implement an irq_chip to manage the interrupt controller
+   hardware.
+4) No need to implement irq_domain_ops.map and irq_domain_ops.unmap,
+   they are unused with hierarchy irq_domain.
+
+Hierarchy irq_domain may also be used to support other architectures,
+such as ARM, ARM64 etc.
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 03f48d936f66..13ba412ce3a0 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -133,6 +133,8 @@ struct irq_domain;
  * @chip:		low level interrupt hardware access
  * @domain:		Interrupt translation domain; responsible for mapping
  *			between hwirq number and linux irq number.
+ * @parent_data:	pointer to parent struct irq_data to support hierarchy
+ *			irq_domain
  * @handler_data:	per-IRQ data for the irq_chip methods
  * @chip_data:		platform-specific per-chip private data for the chip
  *			methods, to allow shared chip implementations
@@ -151,6 +153,9 @@ struct irq_data {
 	unsigned int		state_use_accessors;
 	struct irq_chip		*chip;
 	struct irq_domain	*domain;
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	struct irq_data		*parent_data;
+#endif
 	void			*handler_data;
 	void			*chip_data;
 	struct msi_desc		*msi_desc;
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index b0f9d16e48f6..b20b34b1a8ea 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -38,6 +38,8 @@
 struct device_node;
 struct irq_domain;
 struct of_device_id;
+struct irq_chip;
+struct irq_data;
 
 /* Number of irqs reserved for a legacy isa controller */
 #define NUM_ISA_INTERRUPTS	16
@@ -64,6 +66,16 @@ struct irq_domain_ops {
 	int (*xlate)(struct irq_domain *d, struct device_node *node,
 		     const u32 *intspec, unsigned int intsize,
 		     unsigned long *out_hwirq, unsigned int *out_type);
+
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	/* extended V2 interfaces to support hierarchy irq_domains */
+	int (*alloc)(struct irq_domain *d, unsigned int virq,
+		     unsigned int nr_irqs, void *arg);
+	void (*free)(struct irq_domain *d, unsigned int virq,
+		     unsigned int nr_irqs);
+	int (*activate)(struct irq_domain *d, struct irq_data *irq_data);
+	int (*deactivate)(struct irq_domain *d, struct irq_data *irq_data);
+#endif
 };
 
 extern struct irq_domain_ops irq_generic_chip_ops;
@@ -77,6 +89,7 @@ struct irq_domain_chip_generic;
  * @ops: pointer to irq_domain methods
  * @host_data: private data pointer for use by owner.  Not touched by irq_domain
  *             core code.
+ * @flags: host per irq_domain flags
  *
  * Optional elements
  * @of_node: Pointer to device tree nodes associated with the irq_domain. Used
@@ -84,6 +97,7 @@ struct irq_domain_chip_generic;
  * @gc: Pointer to a list of generic chips. There is a helper function for
  *      setting up one or more generic chips for interrupt controllers
  *      drivers using the generic chip library which uses this pointer.
+ * @parent: Pointer to parent irq_domain to support hierarchy irq_domains
  *
  * Revmap data, used internally by irq_domain
  * @revmap_direct_max_irq: The largest hwirq that can be set for controllers that
@@ -97,10 +111,14 @@ struct irq_domain {
 	const char *name;
 	const struct irq_domain_ops *ops;
 	void *host_data;
+	unsigned int flags;
 
 	/* Optional data */
 	struct device_node *of_node;
 	struct irq_domain_chip_generic *gc;
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	struct irq_domain *parent;
+#endif
 
 	/* reverse map data. The linear map gets appended to the irq_domain */
 	irq_hw_number_t hwirq_max;
@@ -110,6 +128,9 @@ struct irq_domain {
 	unsigned int linear_revmap[];
 };
 
+#define	IRQ_DOMAIN_FLAG_HIERARCHY	0x1
+#define	IRQ_DOMAIN_FLAG_ARCH1		0x10000
+
 #ifdef CONFIG_IRQ_DOMAIN
 struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
 				    irq_hw_number_t hwirq_max, int direct_max,
@@ -220,8 +241,68 @@ int irq_domain_xlate_onetwocell(struct irq_domain *d, struct device_node *ctrlr,
 			const u32 *intspec, unsigned int intsize,
 			irq_hw_number_t *out_hwirq, unsigned int *out_type);
 
+/* V2 interfaces to support hierarchy IRQ domains. */
+extern struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
+						unsigned int virq);
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+extern int irq_domain_set_hwirq_and_chip(struct irq_domain *domain,
+					 unsigned int virq,
+					 irq_hw_number_t hwirq,
+					 struct irq_chip *chip,
+					 void *chip_data);
+extern void irq_domain_reset_irq_data(struct irq_data *irq_data);
+extern int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
+				   unsigned int nr_irqs, int node, void *arg,
+				   bool realloc);
+extern void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs);
+extern int irq_domain_activate_irq(struct irq_data *irq_data);
+extern int irq_domain_deactivate_irq(struct irq_data *irq_data);
+
+static inline int irq_domain_alloc_irqs(struct irq_domain *domain,
+			unsigned int nr_irqs, int node, void *arg)
+{
+	return __irq_domain_alloc_irqs(domain, -1, nr_irqs, node, arg, false);
+}
+
+static inline int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
+				int irq_base, unsigned int nr_irqs, void *arg)
+{
+	if (domain->parent && domain->parent->ops->alloc)
+		return domain->parent->ops->alloc(domain->parent, irq_base,
+						  nr_irqs, arg);
+	return -ENOSYS;
+}
+
+static inline void irq_domain_free_irqs_parent(struct irq_domain *domain,
+					int irq_base, unsigned int nr_irqs)
+{
+	if (domain->parent && domain->parent->ops->free)
+		domain->parent->ops->free(domain->parent, irq_base, nr_irqs);
+}
+
+static inline bool irq_domain_is_hierarchy(struct irq_domain *domain)
+{
+	return domain->flags & IRQ_DOMAIN_FLAG_HIERARCHY;
+}
+#else	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+static inline int irq_domain_activate_irq(struct irq_data *data) { return 0; }
+static inline int irq_domain_deactivate_irq(struct irq_data *data) { return 0; }
+static inline int irq_domain_alloc_irqs(struct irq_domain *domain,
+			unsigned int nr_irqs, int node, void *arg)
+{
+	return -1;
+}
+
+static inline bool irq_domain_is_hierarchy(struct irq_domain *domain)
+{
+	return false;
+}
+#endif	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
 #else /* CONFIG_IRQ_DOMAIN */
 static inline void irq_dispose_mapping(unsigned int virq) { }
+static inline int irq_domain_activate_irq(struct irq_data *data) { return 0; }
+static inline int irq_domain_deactivate_irq(struct irq_data *data) { return 0; }
 #endif /* !CONFIG_IRQ_DOMAIN */
 
 #endif /* _LINUX_IRQDOMAIN_H */
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 225086b2652e..e9b580eccc01 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -55,6 +55,10 @@ config GENERIC_IRQ_CHIP
 config IRQ_DOMAIN
 	bool
 
+config IRQ_DOMAIN_HIERARCHY
+	bool
+	depends on IRQ_DOMAIN
+
 config HANDLE_DOMAIN_IRQ
 	bool
 
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index e5202f00cabc..72a93086216b 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
+#include <linux/irqdomain.h>
 
 #include <trace/events/irq.h>
 
@@ -178,6 +179,7 @@ int irq_startup(struct irq_desc *desc, bool resend)
 	irq_state_clr_disabled(desc);
 	desc->depth = 0;
 
+	irq_domain_activate_irq(&desc->irq_data);
 	if (desc->irq_data.chip->irq_startup) {
 		ret = desc->irq_data.chip->irq_startup(&desc->irq_data);
 		irq_state_clr_masked(desc);
@@ -199,6 +201,7 @@ void irq_shutdown(struct irq_desc *desc)
 		desc->irq_data.chip->irq_disable(&desc->irq_data);
 	else
 		desc->irq_data.chip->irq_mask(&desc->irq_data);
+	irq_domain_deactivate_irq(&desc->irq_data);
 	irq_state_set_masked(desc);
 }
 
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 6534ff6ce02e..7cc9cbb0f240 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -23,6 +23,10 @@ static DEFINE_MUTEX(irq_domain_mutex);
 static DEFINE_MUTEX(revmap_trees_mutex);
 static struct irq_domain *irq_default_domain;
 
+static int irq_domain_alloc_descs(int virq, unsigned int nr_irqs,
+				  irq_hw_number_t hwirq, int node);
+static void irq_domain_check_hierarchy(struct irq_domain *domain);
+
 /**
  * __irq_domain_add() - Allocate a new irq_domain data structure
  * @of_node: optional device-tree node of the interrupt controller
@@ -30,7 +34,7 @@ static struct irq_domain *irq_default_domain;
  * @hwirq_max: Maximum number of interrupts supported by controller
  * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no
  *              direct mapping
- * @ops: map/unmap domain callbacks
+ * @ops: domain callbacks
  * @host_data: Controller private data pointer
  *
  * Allocates and initialize and irq_domain structure.
@@ -56,6 +60,7 @@ struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
 	domain->hwirq_max = hwirq_max;
 	domain->revmap_size = size;
 	domain->revmap_direct_max_irq = direct_max;
+	irq_domain_check_hierarchy(domain);
 
 	mutex_lock(&irq_domain_mutex);
 	list_add(&domain->link, &irq_domain_list);
@@ -109,7 +114,7 @@ EXPORT_SYMBOL_GPL(irq_domain_remove);
  * @first_irq: first number of irq block assigned to the domain,
  *	pass zero to assign irqs on-the-fly. If first_irq is non-zero, then
  *	pre-map all of the irqs in the domain to virqs starting at first_irq.
- * @ops: map/unmap domain callbacks
+ * @ops: domain callbacks
  * @host_data: Controller private data pointer
  *
  * Allocates an irq_domain, and optionally if first_irq is positive then also
@@ -174,10 +179,8 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
 
 	domain = __irq_domain_add(of_node, first_hwirq + size,
 				  first_hwirq + size, 0, ops, host_data);
-	if (!domain)
-		return NULL;
-
-	irq_domain_associate_many(domain, first_irq, first_hwirq, size);
+	if (domain)
+		irq_domain_associate_many(domain, first_irq, first_hwirq, size);
 
 	return domain;
 }
@@ -388,7 +391,6 @@ EXPORT_SYMBOL_GPL(irq_create_direct_mapping);
 unsigned int irq_create_mapping(struct irq_domain *domain,
 				irq_hw_number_t hwirq)
 {
-	unsigned int hint;
 	int virq;
 
 	pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
@@ -410,12 +412,8 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
 	}
 
 	/* Allocate a virtual interrupt number */
-	hint = hwirq % nr_irqs;
-	if (hint == 0)
-		hint++;
-	virq = irq_alloc_desc_from(hint, of_node_to_nid(domain->of_node));
-	if (virq <= 0)
-		virq = irq_alloc_desc_from(1, of_node_to_nid(domain->of_node));
+	virq = irq_domain_alloc_descs(-1, 1, hwirq,
+				      of_node_to_nid(domain->of_node));
 	if (virq <= 0) {
 		pr_debug("-> virq allocation failed\n");
 		return 0;
@@ -471,7 +469,7 @@ unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data)
 	struct irq_domain *domain;
 	irq_hw_number_t hwirq;
 	unsigned int type = IRQ_TYPE_NONE;
-	unsigned int virq;
+	int virq;
 
 	domain = irq_data->np ? irq_find_host(irq_data->np) : irq_default_domain;
 	if (!domain) {
@@ -480,6 +478,11 @@ unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data)
 		return 0;
 	}
 
+	if (irq_domain_is_hierarchy(domain)) {
+		virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, irq_data);
+		return virq <= 0 ? 0 : virq;
+	}
+
 	/* If domain has no translation, then we assume interrupt line */
 	if (domain->ops->xlate == NULL)
 		hwirq = irq_data->args[0];
@@ -540,8 +543,8 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 		return 0;
 
 	if (hwirq < domain->revmap_direct_max_irq) {
-		data = irq_get_irq_data(hwirq);
-		if (data && (data->domain == domain) && (data->hwirq == hwirq))
+		data = irq_domain_get_irq_data(domain, hwirq);
+		if (data && data->hwirq == hwirq)
 			return hwirq;
 	}
 
@@ -709,3 +712,341 @@ const struct irq_domain_ops irq_domain_simple_ops = {
 	.xlate = irq_domain_xlate_onetwocell,
 };
 EXPORT_SYMBOL_GPL(irq_domain_simple_ops);
+
+static int irq_domain_alloc_descs(int virq, unsigned int cnt,
+				  irq_hw_number_t hwirq, int node)
+{
+	unsigned int hint;
+
+	if (virq >= 0) {
+		virq = irq_alloc_descs(virq, virq, cnt, node);
+	} else {
+		hint = hwirq % nr_irqs;
+		if (hint == 0)
+			hint++;
+		virq = irq_alloc_descs_from(hint, cnt, node);
+		if (virq <= 0 && hint > 1)
+			virq = irq_alloc_descs_from(1, cnt, node);
+	}
+
+	return virq;
+}
+
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+static void irq_domain_insert_irq(int virq)
+{
+	struct irq_data *data;
+
+	for (data = irq_get_irq_data(virq); data; data = data->parent_data) {
+		struct irq_domain *domain = data->domain;
+		irq_hw_number_t hwirq = data->hwirq;
+
+		if (hwirq < domain->revmap_size) {
+			domain->linear_revmap[hwirq] = virq;
+		} else {
+			mutex_lock(&revmap_trees_mutex);
+			radix_tree_insert(&domain->revmap_tree, hwirq, data);
+			mutex_unlock(&revmap_trees_mutex);
+		}
+
+		/* If not already assigned, give the domain the chip's name */
+		if (!domain->name && data->chip)
+			domain->name = data->chip->name;
+	}
+
+	irq_clear_status_flags(virq, IRQ_NOREQUEST);
+}
+
+static void irq_domain_remove_irq(int virq)
+{
+	struct irq_data *data;
+
+	irq_set_status_flags(virq, IRQ_NOREQUEST);
+	irq_set_chip_and_handler(virq, NULL, NULL);
+	synchronize_irq(virq);
+	smp_mb();
+
+	for (data = irq_get_irq_data(virq); data; data = data->parent_data) {
+		struct irq_domain *domain = data->domain;
+		irq_hw_number_t hwirq = data->hwirq;
+
+		if (hwirq < domain->revmap_size) {
+			domain->linear_revmap[hwirq] = 0;
+		} else {
+			mutex_lock(&revmap_trees_mutex);
+			radix_tree_delete(&domain->revmap_tree, hwirq);
+			mutex_unlock(&revmap_trees_mutex);
+		}
+	}
+}
+
+static struct irq_data *irq_domain_insert_irq_data(struct irq_domain *domain,
+						   struct irq_data *child)
+{
+	struct irq_data *irq_data;
+
+	irq_data = kzalloc_node(sizeof(*irq_data), GFP_KERNEL, child->node);
+	if (irq_data) {
+		child->parent_data = irq_data;
+		irq_data->irq = child->irq;
+		irq_data->node = child->node;
+		irq_data->domain = domain;
+	}
+
+	return irq_data;
+}
+
+static void irq_domain_free_irq_data(unsigned int virq, unsigned int nr_irqs)
+{
+	int i;
+	struct irq_data *irq_data, *tmp;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_get_irq_data(virq + i);
+		tmp = irq_data->parent_data;
+		irq_data->parent_data = NULL;
+		irq_data->domain = NULL;
+
+		while (tmp) {
+			irq_data = tmp;
+			tmp = tmp->parent_data;
+			kfree(irq_data);
+		}
+	}
+}
+
+static int irq_domain_alloc_irq_data(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	int i;
+	struct irq_data *irq_data;
+	struct irq_domain *parent;
+
+	/* The outermost irq_data is embedded in struct irq_desc */
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_get_irq_data(virq + i);
+		irq_data->domain = domain;
+
+		for (parent = domain->parent; parent; parent = parent->parent) {
+			irq_data = irq_domain_insert_irq_data(parent, irq_data);
+			if (!irq_data) {
+				irq_domain_free_irq_data(virq, i + 1);
+				return -ENOMEM;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * irq_domain_get_irq_data - Get irq_data associated with @virq and @domain
+ * @domain: domain to match
+ * @virq: IRQ number to get irq_data
+ */
+struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
+					 unsigned int virq)
+{
+	struct irq_data *irq_data;
+
+	for (irq_data = irq_get_irq_data(virq); irq_data;
+	     irq_data = irq_data->parent_data)
+		if (irq_data->domain == domain)
+			return irq_data;
+
+	return NULL;
+}
+
+int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
+				  irq_hw_number_t hwirq, struct irq_chip *chip,
+				  void *chip_data)
+{
+	struct irq_data *irq_data = irq_domain_get_irq_data(domain, virq);
+
+	if (!irq_data)
+		return -ENOENT;
+
+	irq_data->hwirq = hwirq;
+	irq_data->chip = chip ? chip : &no_irq_chip;
+	irq_data->chip_data = chip_data;
+
+	return 0;
+}
+
+void irq_domain_reset_irq_data(struct irq_data *irq_data)
+{
+	irq_data->hwirq = 0;
+	irq_data->chip = &no_irq_chip;
+	irq_data->chip_data = NULL;
+}
+
+/**
+ * __irq_domain_alloc_irqs - Allocate IRQs from domain
+ * @domain: domain to allocate from
+ * @irq_base: allocate specified IRQ nubmer if irq_base >= 0
+ * @nr_irqs: number of IRQs to allocate
+ * @node: NUMA node id for memory allocation
+ * @arg: domain specific argument
+ * @realloc: IRQ descriptors have already been allocated if true
+ *
+ * Allocate IRQ numbers and initialized all data structures to support
+ * hiearchy IRQ domains.
+ * Parameter @realloc is mainly to support legacy IRQs.
+ * Returns error code or allocated IRQ number
+ *
+ * The whole process to setup an IRQ has been split into two steps.
+ * The first step, __irq_domain_alloc_irqs(), is to allocate IRQ
+ * descriptor and required hardware resources. The second step,
+ * irq_domain_activate_irq(), is to program hardwares with preallocated
+ * resources. In this way, it's easier to rollback when failing to
+ * allocate resources.
+ */
+int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
+			    unsigned int nr_irqs, int node, void *arg,
+			    bool realloc)
+{
+	int i, ret, virq;
+
+	if (domain == NULL) {
+		domain = irq_default_domain;
+		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
+			return -EINVAL;
+	}
+
+	if (!domain->ops->alloc) {
+		pr_debug("domain->ops->alloc() is NULL\n");
+		return -ENOSYS;
+	}
+
+	if (realloc && irq_base >= 0) {
+		virq = irq_base;
+	} else {
+		virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node);
+		if (virq < 0) {
+			pr_debug("cannot allocate IRQ(base %d, count %d)\n",
+				 irq_base, nr_irqs);
+			return virq;
+		}
+	}
+
+	if (irq_domain_alloc_irq_data(domain, virq, nr_irqs)) {
+		pr_debug("cannot allocate memory for IRQ%d\n", virq);
+		ret = -ENOMEM;
+		goto out_free_desc;
+	}
+
+	mutex_lock(&irq_domain_mutex);
+	ret = domain->ops->alloc(domain, virq, nr_irqs, arg);
+	if (ret < 0) {
+		mutex_unlock(&irq_domain_mutex);
+		goto out_free_irq_data;
+	}
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_insert_irq(virq + i);
+	mutex_unlock(&irq_domain_mutex);
+
+	return virq;
+
+out_free_irq_data:
+	irq_domain_free_irq_data(virq, nr_irqs);
+out_free_desc:
+	irq_free_descs(virq, nr_irqs);
+	return ret;
+}
+
+/**
+ * irq_domain_free_irqs - Free IRQ number and associated data structures
+ * @virq: base IRQ number
+ * @nr_irqs: number of IRQs to free
+ */
+void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
+{
+	int i;
+	struct irq_data *data = irq_get_irq_data(virq);
+
+	if (WARN(!data || !data->domain || !data->domain->ops->free,
+		 "NULL pointer, cannot free irq\n"))
+		return;
+
+	mutex_lock(&irq_domain_mutex);
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_remove_irq(virq + i);
+	data->domain->ops->free(data->domain, virq, nr_irqs);
+	mutex_unlock(&irq_domain_mutex);
+
+	irq_domain_free_irq_data(virq, nr_irqs);
+	irq_free_descs(virq, nr_irqs);
+}
+
+/**
+ * irq_domain_activate_irq - Call domain_ops->activate recursively to activate
+ *			     interrupt
+ * @irq_data: outermost irq_data associated with interrupt
+ *
+ * This is the second step to call domain_ops->activate to program interrupt
+ * controllers, so the interrupt could actually get delivered.
+ */
+int irq_domain_activate_irq(struct irq_data *irq_data)
+{
+	int ret = 0;
+
+	if (irq_data && irq_data->domain) {
+		struct irq_domain *domain = irq_data->domain;
+
+		if (irq_data->parent_data)
+			ret = irq_domain_activate_irq(irq_data->parent_data);
+		if (ret == 0 && domain->ops->activate)
+			ret = domain->ops->activate(domain, irq_data);
+	}
+
+	return ret;
+}
+
+/**
+ * irq_domain_deactivate_irq - Call domain_ops->deactivate recursively to
+ *			       deactivate interrupt
+ * @irq_data: outermost irq_data associated with interrupt
+ *
+ * It calls domain_ops->deactivate to program interrupt controllers to disable
+ * interrupt delivery.
+ */
+int irq_domain_deactivate_irq(struct irq_data *irq_data)
+{
+	int ret = 0;
+
+	if (irq_data && irq_data->domain) {
+		struct irq_domain *domain = irq_data->domain;
+
+		if (domain->ops->deactivate)
+			ret = domain->ops->deactivate(domain, irq_data);
+		if (ret == 0 && irq_data->parent_data)
+			ret = irq_domain_deactivate_irq(irq_data->parent_data);
+	}
+
+	return ret;
+}
+
+static void irq_domain_check_hierarchy(struct irq_domain *domain)
+{
+	/* Hierarchy irq_domains must implement callback alloc() */
+	if (domain->ops->alloc)
+		domain->flags |= IRQ_DOMAIN_FLAG_HIERARCHY;
+}
+#else	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+/**
+ * irq_domain_get_irq_data - Get irq_data associated with @virq and @domain
+ * @domain: domain to match
+ * @virq: IRQ number to get irq_data
+ */
+struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
+					 unsigned int virq)
+{
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+
+	return (irq_data && irq_data->domain == domain) ? irq_data : NULL;
+}
+
+static void irq_domain_check_hierarchy(struct irq_domain *domain)
+{
+}
+#endif	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
