1 files changed, 524 insertions, 127 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 31805f237396..4f4f60015e8a 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1,5 +1,6 @@
 #define pr_fmt(fmt)  "irq: " fmt
 
+#include <linux/acpi.h>
 #include <linux/debugfs.h>
 #include <linux/hardirq.h>
 #include <linux/interrupt.h>
@@ -20,45 +21,77 @@
 static LIST_HEAD(irq_domain_list);
 static DEFINE_MUTEX(irq_domain_mutex);
 
-static DEFINE_MUTEX(revmap_trees_mutex);
 static struct irq_domain *irq_default_domain;
 
 static void irq_domain_check_hierarchy(struct irq_domain *domain);
 
 struct irqchip_fwid {
-	struct fwnode_handle fwnode;
-	char *name;
+	struct fwnode_handle	fwnode;
+	unsigned int		type;
+	char			*name;
 	void *data;
 };
 
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static void debugfs_add_domain_dir(struct irq_domain *d);
+static void debugfs_remove_domain_dir(struct irq_domain *d);
+#else
+static inline void debugfs_add_domain_dir(struct irq_domain *d) { }
+static inline void debugfs_remove_domain_dir(struct irq_domain *d) { }
+#endif
+
+const struct fwnode_operations irqchip_fwnode_ops;
+EXPORT_SYMBOL_GPL(irqchip_fwnode_ops);
+
 /**
  * irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for
  *                           identifying an irq domain
- * @data: optional user-provided data
+ * @type:	Type of irqchip_fwnode. See linux/irqdomain.h
+ * @name:	Optional user provided domain name
+ * @id:		Optional user provided id if name != NULL
+ * @data:	Optional user-provided data
  *
- * Allocate a struct device_node, and return a poiner to the embedded
+ * Allocate a struct irqchip_fwid, and return a poiner to the embedded
  * fwnode_handle (or NULL on failure).
+ *
+ * Note: The types IRQCHIP_FWNODE_NAMED and IRQCHIP_FWNODE_NAMED_ID are
+ * solely to transport name information to irqdomain creation code. The
+ * node is not stored. For other types the pointer is kept in the irq
+ * domain struct.
  */
-struct fwnode_handle *irq_domain_alloc_fwnode(void *data)
+struct fwnode_handle *__irq_domain_alloc_fwnode(unsigned int type, int id,
+						const char *name, void *data)
 {
 	struct irqchip_fwid *fwid;
-	char *name;
+	char *n;
 
 	fwid = kzalloc(sizeof(*fwid), GFP_KERNEL);
-	name = kasprintf(GFP_KERNEL, "irqchip@%p", data);
 
-	if (!fwid || !name) {
+	switch (type) {
+	case IRQCHIP_FWNODE_NAMED:
+		n = kasprintf(GFP_KERNEL, "%s", name);
+		break;
+	case IRQCHIP_FWNODE_NAMED_ID:
+		n = kasprintf(GFP_KERNEL, "%s-%d", name, id);
+		break;
+	default:
+		n = kasprintf(GFP_KERNEL, "irqchip@%p", data);
+		break;
+	}
+
+	if (!fwid || !n) {
 		kfree(fwid);
-		kfree(name);
+		kfree(n);
 		return NULL;
 	}
 
-	fwid->name = name;
+	fwid->type = type;
+	fwid->name = n;
 	fwid->data = data;
-	fwid->fwnode.type = FWNODE_IRQCHIP;
+	fwid->fwnode.ops = &irqchip_fwnode_ops;
 	return &fwid->fwnode;
 }
-EXPORT_SYMBOL_GPL(irq_domain_alloc_fwnode);
+EXPORT_SYMBOL_GPL(__irq_domain_alloc_fwnode);
 
 /**
  * irq_domain_free_fwnode - Free a non-OF-backed fwnode_handle
@@ -97,26 +130,96 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
 				    void *host_data)
 {
 	struct device_node *of_node = to_of_node(fwnode);
+	struct irqchip_fwid *fwid;
 	struct irq_domain *domain;
 
+	static atomic_t unknown_domains;
+
 	domain = kzalloc_node(sizeof(*domain) + (sizeof(unsigned int) * size),
 			      GFP_KERNEL, of_node_to_nid(of_node));
 	if (WARN_ON(!domain))
 		return NULL;
 
+	if (fwnode && is_fwnode_irqchip(fwnode)) {
+		fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
+
+		switch (fwid->type) {
+		case IRQCHIP_FWNODE_NAMED:
+		case IRQCHIP_FWNODE_NAMED_ID:
+			domain->name = kstrdup(fwid->name, GFP_KERNEL);
+			if (!domain->name) {
+				kfree(domain);
+				return NULL;
+			}
+			domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+			break;
+		default:
+			domain->fwnode = fwnode;
+			domain->name = fwid->name;
+			break;
+		}
+#ifdef CONFIG_ACPI
+	} else if (is_acpi_device_node(fwnode)) {
+		struct acpi_buffer buf = {
+			.length = ACPI_ALLOCATE_BUFFER,
+		};
+		acpi_handle handle;
+
+		handle = acpi_device_handle(to_acpi_device_node(fwnode));
+		if (acpi_get_name(handle, ACPI_FULL_PATHNAME, &buf) == AE_OK) {
+			domain->name = buf.pointer;
+			domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+		}
+
+		domain->fwnode = fwnode;
+#endif
+	} else if (of_node) {
+		char *name;
+
+		/*
+		 * DT paths contain '/', which debugfs is legitimately
+		 * unhappy about. Replace them with ':', which does
+		 * the trick and is not as offensive as '\'...
+		 */
+		name = kstrdup(of_node_full_name(of_node), GFP_KERNEL);
+		if (!name) {
+			kfree(domain);
+			return NULL;
+		}
+
+		strreplace(name, '/', ':');
+
+		domain->name = name;
+		domain->fwnode = fwnode;
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+	}
+
+	if (!domain->name) {
+		if (fwnode)
+			pr_err("Invalid fwnode type for irqdomain\n");
+		domain->name = kasprintf(GFP_KERNEL, "unknown-%d",
+					 atomic_inc_return(&unknown_domains));
+		if (!domain->name) {
+			kfree(domain);
+			return NULL;
+		}
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+	}
+
 	of_node_get(of_node);
 
 	/* Fill structure */
 	INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
+	mutex_init(&domain->revmap_tree_mutex);
 	domain->ops = ops;
 	domain->host_data = host_data;
-	domain->fwnode = fwnode;
 	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);
+	debugfs_add_domain_dir(domain);
 	list_add(&domain->link, &irq_domain_list);
 	mutex_unlock(&irq_domain_mutex);
 
@@ -136,6 +239,7 @@ EXPORT_SYMBOL_GPL(__irq_domain_add);
 void irq_domain_remove(struct irq_domain *domain)
 {
 	mutex_lock(&irq_domain_mutex);
+	debugfs_remove_domain_dir(domain);
 
 	WARN_ON(!radix_tree_empty(&domain->revmap_tree));
 
@@ -152,10 +256,43 @@ void irq_domain_remove(struct irq_domain *domain)
 	pr_debug("Removed domain %s\n", domain->name);
 
 	of_node_put(irq_domain_get_of_node(domain));
+	if (domain->flags & IRQ_DOMAIN_NAME_ALLOCATED)
+		kfree(domain->name);
 	kfree(domain);
 }
 EXPORT_SYMBOL_GPL(irq_domain_remove);
 
+void irq_domain_update_bus_token(struct irq_domain *domain,
+				 enum irq_domain_bus_token bus_token)
+{
+	char *name;
+
+	if (domain->bus_token == bus_token)
+		return;
+
+	mutex_lock(&irq_domain_mutex);
+
+	domain->bus_token = bus_token;
+
+	name = kasprintf(GFP_KERNEL, "%s-%d", domain->name, bus_token);
+	if (!name) {
+		mutex_unlock(&irq_domain_mutex);
+		return;
+	}
+
+	debugfs_remove_domain_dir(domain);
+
+	if (domain->flags & IRQ_DOMAIN_NAME_ALLOCATED)
+		kfree(domain->name);
+	else
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+
+	domain->name = name;
+	debugfs_add_domain_dir(domain);
+
+	mutex_unlock(&irq_domain_mutex);
+}
+
 /**
  * irq_domain_add_simple() - Register an irq_domain and optionally map a range of irqs
  * @of_node: pointer to interrupt controller's device tree node.
@@ -319,6 +456,31 @@ void irq_set_default_host(struct irq_domain *domain)
 }
 EXPORT_SYMBOL_GPL(irq_set_default_host);
 
+static void irq_domain_clear_mapping(struct irq_domain *domain,
+				     irq_hw_number_t hwirq)
+{
+	if (hwirq < domain->revmap_size) {
+		domain->linear_revmap[hwirq] = 0;
+	} else {
+		mutex_lock(&domain->revmap_tree_mutex);
+		radix_tree_delete(&domain->revmap_tree, hwirq);
+		mutex_unlock(&domain->revmap_tree_mutex);
+	}
+}
+
+static void irq_domain_set_mapping(struct irq_domain *domain,
+				   irq_hw_number_t hwirq,
+				   struct irq_data *irq_data)
+{
+	if (hwirq < domain->revmap_size) {
+		domain->linear_revmap[hwirq] = irq_data->irq;
+	} else {
+		mutex_lock(&domain->revmap_tree_mutex);
+		radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
+		mutex_unlock(&domain->revmap_tree_mutex);
+	}
+}
+
 void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
 {
 	struct irq_data *irq_data = irq_get_irq_data(irq);
@@ -344,15 +506,10 @@ void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
 
 	irq_data->domain = NULL;
 	irq_data->hwirq = 0;
+	domain->mapcount--;
 
 	/* Clear reverse map for this 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);
-	}
+	irq_domain_clear_mapping(domain, hwirq);
 }
 
 int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
@@ -395,13 +552,8 @@ int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
 			domain->name = irq_data->chip->name;
 	}
 
-	if (hwirq < domain->revmap_size) {
-		domain->linear_revmap[hwirq] = virq;
-	} else {
-		mutex_lock(&revmap_trees_mutex);
-		radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
-		mutex_unlock(&revmap_trees_mutex);
-	}
+	domain->mapcount++;
+	irq_domain_set_mapping(domain, hwirq, irq_data);
 	mutex_unlock(&irq_domain_mutex);
 
 	irq_clear_status_flags(virq, IRQ_NOREQUEST);
@@ -746,13 +898,53 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 EXPORT_SYMBOL_GPL(irq_find_mapping);
 
 #ifdef CONFIG_IRQ_DOMAIN_DEBUG
+static void virq_debug_show_one(struct seq_file *m, struct irq_desc *desc)
+{
+	struct irq_domain *domain;
+	struct irq_data *data;
+
+	domain = desc->irq_data.domain;
+	data = &desc->irq_data;
+
+	while (domain) {
+		unsigned int irq = data->irq;
+		unsigned long hwirq = data->hwirq;
+		struct irq_chip *chip;
+		bool direct;
+
+		if (data == &desc->irq_data)
+			seq_printf(m, "%5d  ", irq);
+		else
+			seq_printf(m, "%5d+ ", irq);
+		seq_printf(m, "0x%05lx  ", hwirq);
+
+		chip = irq_data_get_irq_chip(data);
+		seq_printf(m, "%-15s  ", (chip && chip->name) ? chip->name : "none");
+
+		seq_printf(m, "0x%p  ", irq_data_get_irq_chip_data(data));
+
+		seq_printf(m, "   %c    ", (desc->action && desc->action->handler) ? '*' : ' ');
+		direct = (irq == hwirq) && (irq < domain->revmap_direct_max_irq);
+		seq_printf(m, "%6s%-8s  ",
+			   (hwirq < domain->revmap_size) ? "LINEAR" : "RADIX",
+			   direct ? "(DIRECT)" : "");
+		seq_printf(m, "%s\n", domain->name);
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+		domain = domain->parent;
+		data = data->parent_data;
+#else
+		domain = NULL;
+#endif
+	}
+}
+
 static int virq_debug_show(struct seq_file *m, void *private)
 {
 	unsigned long flags;
 	struct irq_desc *desc;
 	struct irq_domain *domain;
 	struct radix_tree_iter iter;
-	void *data, **slot;
+	void __rcu **slot;
 	int i;
 
 	seq_printf(m, " %-16s  %-6s  %-10s  %-10s  %s\n",
@@ -760,15 +952,26 @@ static int virq_debug_show(struct seq_file *m, void *private)
 	mutex_lock(&irq_domain_mutex);
 	list_for_each_entry(domain, &irq_domain_list, link) {
 		struct device_node *of_node;
+		const char *name;
+
 		int count = 0;
+
 		of_node = irq_domain_get_of_node(domain);
+		if (of_node)
+			name = of_node_full_name(of_node);
+		else if (is_fwnode_irqchip(domain->fwnode))
+			name = container_of(domain->fwnode, struct irqchip_fwid,
+					    fwnode)->name;
+		else
+			name = "";
+
 		radix_tree_for_each_slot(slot, &domain->revmap_tree, &iter, 0)
 			count++;
 		seq_printf(m, "%c%-16s  %6u  %10u  %10u  %s\n",
 			   domain == irq_default_domain ? '*' : ' ', domain->name,
 			   domain->revmap_size + count, domain->revmap_size,
 			   domain->revmap_direct_max_irq,
-			   of_node ? of_node_full_name(of_node) : "");
+			   name);
 	}
 	mutex_unlock(&irq_domain_mutex);
 
@@ -782,30 +985,7 @@ static int virq_debug_show(struct seq_file *m, void *private)
 			continue;
 
 		raw_spin_lock_irqsave(&desc->lock, flags);
-		domain = desc->irq_data.domain;
-
-		if (domain) {
-			struct irq_chip *chip;
-			int hwirq = desc->irq_data.hwirq;
-			bool direct;
-
-			seq_printf(m, "%5d  ", i);
-			seq_printf(m, "0x%05x  ", hwirq);
-
-			chip = irq_desc_get_chip(desc);
-			seq_printf(m, "%-15s  ", (chip && chip->name) ? chip->name : "none");
-
-			data = irq_desc_get_chip_data(desc);
-			seq_printf(m, data ? "0x%p  " : "  %p  ", data);
-
-			seq_printf(m, "   %c    ", (desc->action && desc->action->handler) ? '*' : ' ');
-			direct = (i == hwirq) && (i < domain->revmap_direct_max_irq);
-			seq_printf(m, "%6s%-8s  ",
-				   (hwirq < domain->revmap_size) ? "LINEAR" : "RADIX",
-				   direct ? "(DIRECT)" : "");
-			seq_printf(m, "%s\n", desc->irq_data.domain->name);
-		}
-
+		virq_debug_show_one(m, desc);
 		raw_spin_unlock_irqrestore(&desc->lock, flags);
 	}
 
@@ -971,15 +1151,9 @@ static void irq_domain_insert_irq(int virq)
 
 	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);
-		}
+		domain->mapcount++;
+		irq_domain_set_mapping(domain, data->hwirq, data);
 
 		/* If not already assigned, give the domain the chip's name */
 		if (!domain->name && data->chip)
@@ -1002,13 +1176,8 @@ static void irq_domain_remove_irq(int virq)
 		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);
-		}
+		domain->mapcount--;
+		irq_domain_clear_mapping(domain, hwirq);
 	}
 }
 
@@ -1189,43 +1358,19 @@ void irq_domain_free_irqs_top(struct irq_domain *domain, unsigned int virq,
 	irq_domain_free_irqs_common(domain, virq, nr_irqs);
 }
 
-static bool irq_domain_is_auto_recursive(struct irq_domain *domain)
-{
-	return domain->flags & IRQ_DOMAIN_FLAG_AUTO_RECURSIVE;
-}
-
-static void irq_domain_free_irqs_recursive(struct irq_domain *domain,
+static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
 					   unsigned int irq_base,
 					   unsigned int nr_irqs)
 {
-	domain->ops->free(domain, irq_base, nr_irqs);
-	if (irq_domain_is_auto_recursive(domain)) {
-		BUG_ON(!domain->parent);
-		irq_domain_free_irqs_recursive(domain->parent, irq_base,
-					       nr_irqs);
-	}
+	if (domain->ops->free)
+		domain->ops->free(domain, irq_base, nr_irqs);
 }
 
-int irq_domain_alloc_irqs_recursive(struct irq_domain *domain,
+int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 				    unsigned int irq_base,
 				    unsigned int nr_irqs, void *arg)
 {
-	int ret = 0;
-	struct irq_domain *parent = domain->parent;
-	bool recursive = irq_domain_is_auto_recursive(domain);
-
-	BUG_ON(recursive && !parent);
-	if (recursive)
-		ret = irq_domain_alloc_irqs_recursive(parent, irq_base,
-						      nr_irqs, arg);
-	if (ret < 0)
-		return ret;
-
-	ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg);
-	if (ret < 0 && recursive)
-		irq_domain_free_irqs_recursive(parent, irq_base, nr_irqs);
-
-	return ret;
+	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
 }
 
 /**
@@ -1286,7 +1431,7 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 	}
 
 	mutex_lock(&irq_domain_mutex);
-	ret = irq_domain_alloc_irqs_recursive(domain, virq, nr_irqs, arg);
+	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
 	if (ret < 0) {
 		mutex_unlock(&irq_domain_mutex);
 		goto out_free_irq_data;
@@ -1304,6 +1449,175 @@ out_free_desc:
 	return ret;
 }
 
+/* The irq_data was moved, fix the revmap to refer to the new location */
+static void irq_domain_fix_revmap(struct irq_data *d)
+{
+	void __rcu **slot;
+
+	if (d->hwirq < d->domain->revmap_size)
+		return; /* Not using radix tree. */
+
+	/* Fix up the revmap. */
+	mutex_lock(&d->domain->revmap_tree_mutex);
+	slot = radix_tree_lookup_slot(&d->domain->revmap_tree, d->hwirq);
+	if (slot)
+		radix_tree_replace_slot(&d->domain->revmap_tree, slot, d);
+	mutex_unlock(&d->domain->revmap_tree_mutex);
+}
+
+/**
+ * irq_domain_push_irq() - Push a domain in to the top of a hierarchy.
+ * @domain:	Domain to push.
+ * @virq:	Irq to push the domain in to.
+ * @arg:	Passed to the irq_domain_ops alloc() function.
+ *
+ * For an already existing irqdomain hierarchy, as might be obtained
+ * via a call to pci_enable_msix(), add an additional domain to the
+ * head of the processing chain.  Must be called before request_irq()
+ * has been called.
+ */
+int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
+{
+	struct irq_data *child_irq_data;
+	struct irq_data *root_irq_data = irq_get_irq_data(virq);
+	struct irq_desc *desc;
+	int rv = 0;
+
+	/*
+	 * Check that no action has been set, which indicates the virq
+	 * is in a state where this function doesn't have to deal with
+	 * races between interrupt handling and maintaining the
+	 * hierarchy.  This will catch gross misuse.  Attempting to
+	 * make the check race free would require holding locks across
+	 * calls to struct irq_domain_ops->alloc(), which could lead
+	 * to deadlock, so we just do a simple check before starting.
+	 */
+	desc = irq_to_desc(virq);
+	if (!desc)
+		return -EINVAL;
+	if (WARN_ON(desc->action))
+		return -EBUSY;
+
+	if (domain == NULL)
+		return -EINVAL;
+
+	if (WARN_ON(!irq_domain_is_hierarchy(domain)))
+		return -EINVAL;
+
+	if (!root_irq_data)
+		return -EINVAL;
+
+	if (domain->parent != root_irq_data->domain)
+		return -EINVAL;
+
+	child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,
+				      irq_data_get_node(root_irq_data));
+	if (!child_irq_data)
+		return -ENOMEM;
+
+	mutex_lock(&irq_domain_mutex);
+
+	/* Copy the original irq_data. */
+	*child_irq_data = *root_irq_data;
+
+	/*
+	 * Overwrite the root_irq_data, which is embedded in struct
+	 * irq_desc, with values for this domain.
+	 */
+	root_irq_data->parent_data = child_irq_data;
+	root_irq_data->domain = domain;
+	root_irq_data->mask = 0;
+	root_irq_data->hwirq = 0;
+	root_irq_data->chip = NULL;
+	root_irq_data->chip_data = NULL;
+
+	/* May (probably does) set hwirq, chip, etc. */
+	rv = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
+	if (rv) {
+		/* Restore the original irq_data. */
+		*root_irq_data = *child_irq_data;
+		goto error;
+	}
+
+	irq_domain_fix_revmap(child_irq_data);
+	irq_domain_set_mapping(domain, root_irq_data->hwirq, root_irq_data);
+
+error:
+	mutex_unlock(&irq_domain_mutex);
+
+	return rv;
+}
+EXPORT_SYMBOL_GPL(irq_domain_push_irq);
+
+/**
+ * irq_domain_pop_irq() - Remove a domain from the top of a hierarchy.
+ * @domain:	Domain to remove.
+ * @virq:	Irq to remove the domain from.
+ *
+ * Undo the effects of a call to irq_domain_push_irq().  Must be
+ * called either before request_irq() or after free_irq().
+ */
+int irq_domain_pop_irq(struct irq_domain *domain, int virq)
+{
+	struct irq_data *root_irq_data = irq_get_irq_data(virq);
+	struct irq_data *child_irq_data;
+	struct irq_data *tmp_irq_data;
+	struct irq_desc *desc;
+
+	/*
+	 * Check that no action is set, which indicates the virq is in
+	 * a state where this function doesn't have to deal with races
+	 * between interrupt handling and maintaining the hierarchy.
+	 * This will catch gross misuse.  Attempting to make the check
+	 * race free would require holding locks across calls to
+	 * struct irq_domain_ops->free(), which could lead to
+	 * deadlock, so we just do a simple check before starting.
+	 */
+	desc = irq_to_desc(virq);
+	if (!desc)
+		return -EINVAL;
+	if (WARN_ON(desc->action))
+		return -EBUSY;
+
+	if (domain == NULL)
+		return -EINVAL;
+
+	if (!root_irq_data)
+		return -EINVAL;
+
+	tmp_irq_data = irq_domain_get_irq_data(domain, virq);
+
+	/* We can only "pop" if this domain is at the top of the list */
+	if (WARN_ON(root_irq_data != tmp_irq_data))
+		return -EINVAL;
+
+	if (WARN_ON(root_irq_data->domain != domain))
+		return -EINVAL;
+
+	child_irq_data = root_irq_data->parent_data;
+	if (WARN_ON(!child_irq_data))
+		return -EINVAL;
+
+	mutex_lock(&irq_domain_mutex);
+
+	root_irq_data->parent_data = NULL;
+
+	irq_domain_clear_mapping(domain, root_irq_data->hwirq);
+	irq_domain_free_irqs_hierarchy(domain, virq, 1);
+
+	/* Restore the original irq_data. */
+	*root_irq_data = *child_irq_data;
+
+	irq_domain_fix_revmap(root_irq_data);
+
+	mutex_unlock(&irq_domain_mutex);
+
+	kfree(child_irq_data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_pop_irq);
+
 /**
  * irq_domain_free_irqs - Free IRQ number and associated data structures
  * @virq:	base IRQ number
@@ -1321,7 +1635,7 @@ void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
 	mutex_lock(&irq_domain_mutex);
 	for (i = 0; i < nr_irqs; i++)
 		irq_domain_remove_irq(virq + i);
-	irq_domain_free_irqs_recursive(data->domain, virq, nr_irqs);
+	irq_domain_free_irqs_hierarchy(data->domain, virq, nr_irqs);
 	mutex_unlock(&irq_domain_mutex);
 
 	irq_domain_free_irq_data(virq, nr_irqs);
@@ -1341,15 +1655,11 @@ int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
 				 unsigned int irq_base, unsigned int nr_irqs,
 				 void *arg)
 {
-	/* irq_domain_alloc_irqs_recursive() has called parent's alloc() */
-	if (irq_domain_is_auto_recursive(domain))
-		return 0;
+	if (!domain->parent)
+		return -ENOSYS;
 
-	domain = domain->parent;
-	if (domain)
-		return irq_domain_alloc_irqs_recursive(domain, irq_base,
-						       nr_irqs, arg);
-	return -ENOSYS;
+	return irq_domain_alloc_irqs_hierarchy(domain->parent, irq_base,
+					       nr_irqs, arg);
 }
 EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
 
@@ -1364,35 +1674,43 @@ EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
 void irq_domain_free_irqs_parent(struct irq_domain *domain,
 				 unsigned int irq_base, unsigned int nr_irqs)
 {
-	/* irq_domain_free_irqs_recursive() will call parent's free */
-	if (!irq_domain_is_auto_recursive(domain) && domain->parent)
-		irq_domain_free_irqs_recursive(domain->parent, irq_base,
-					       nr_irqs);
+	if (!domain->parent)
+		return;
+
+	irq_domain_free_irqs_hierarchy(domain->parent, irq_base, nr_irqs);
 }
 EXPORT_SYMBOL_GPL(irq_domain_free_irqs_parent);
 
-static void __irq_domain_activate_irq(struct irq_data *irq_data)
+static void __irq_domain_deactivate_irq(struct irq_data *irq_data)
 {
 	if (irq_data && irq_data->domain) {
 		struct irq_domain *domain = irq_data->domain;
 
+		if (domain->ops->deactivate)
+			domain->ops->deactivate(domain, irq_data);
 		if (irq_data->parent_data)
-			__irq_domain_activate_irq(irq_data->parent_data);
-		if (domain->ops->activate)
-			domain->ops->activate(domain, irq_data);
+			__irq_domain_deactivate_irq(irq_data->parent_data);
 	}
 }
 
-static void __irq_domain_deactivate_irq(struct irq_data *irq_data)
+static int __irq_domain_activate_irq(struct irq_data *irqd, bool early)
 {
-	if (irq_data && irq_data->domain) {
-		struct irq_domain *domain = irq_data->domain;
+	int ret = 0;
 
-		if (domain->ops->deactivate)
-			domain->ops->deactivate(domain, irq_data);
-		if (irq_data->parent_data)
-			__irq_domain_deactivate_irq(irq_data->parent_data);
+	if (irqd && irqd->domain) {
+		struct irq_domain *domain = irqd->domain;
+
+		if (irqd->parent_data)
+			ret = __irq_domain_activate_irq(irqd->parent_data,
+							early);
+		if (!ret && domain->ops->activate) {
+			ret = domain->ops->activate(domain, irqd, early);
+			/* Rollback in case of error */
+			if (ret && irqd->parent_data)
+				__irq_domain_deactivate_irq(irqd->parent_data);
+		}
 	}
+	return ret;
 }
 
 /**
@@ -1403,12 +1721,15 @@ static void __irq_domain_deactivate_irq(struct irq_data *irq_data)
  * This is the second step to call domain_ops->activate to program interrupt
  * controllers, so the interrupt could actually get delivered.
  */
-void irq_domain_activate_irq(struct irq_data *irq_data)
+int irq_domain_activate_irq(struct irq_data *irq_data, bool early)
 {
-	if (!irqd_is_activated(irq_data)) {
-		__irq_domain_activate_irq(irq_data);
+	int ret = 0;
+
+	if (!irqd_is_activated(irq_data))
+		ret = __irq_domain_activate_irq(irq_data, early);
+	if (!ret)
 		irqd_set_activated(irq_data);
-	}
+	return ret;
 }
 
 /**
@@ -1487,3 +1808,79 @@ static void irq_domain_check_hierarchy(struct irq_domain *domain)
 {
 }
 #endif	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static struct dentry *domain_dir;
+
+static void
+irq_domain_debug_show_one(struct seq_file *m, struct irq_domain *d, int ind)
+{
+	seq_printf(m, "%*sname:   %s\n", ind, "", d->name);
+	seq_printf(m, "%*ssize:   %u\n", ind + 1, "",
+		   d->revmap_size + d->revmap_direct_max_irq);
+	seq_printf(m, "%*smapped: %u\n", ind + 1, "", d->mapcount);
+	seq_printf(m, "%*sflags:  0x%08x\n", ind +1 , "", d->flags);
+	if (d->ops && d->ops->debug_show)
+		d->ops->debug_show(m, d, NULL, ind + 1);
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	if (!d->parent)
+		return;
+	seq_printf(m, "%*sparent: %s\n", ind + 1, "", d->parent->name);
+	irq_domain_debug_show_one(m, d->parent, ind + 4);
+#endif
+}
+
+static int irq_domain_debug_show(struct seq_file *m, void *p)
+{
+	struct irq_domain *d = m->private;
+
+	/* Default domain? Might be NULL */
+	if (!d) {
+		if (!irq_default_domain)
+			return 0;
+		d = irq_default_domain;
+	}
+	irq_domain_debug_show_one(m, d, 0);
+	return 0;
+}
+
+static int irq_domain_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, irq_domain_debug_show, inode->i_private);
+}
+
+static const struct file_operations dfs_domain_ops = {
+	.open		= irq_domain_debug_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void debugfs_add_domain_dir(struct irq_domain *d)
+{
+	if (!d->name || !domain_dir || d->debugfs_file)
+		return;
+	d->debugfs_file = debugfs_create_file(d->name, 0444, domain_dir, d,
+					      &dfs_domain_ops);
+}
+
+static void debugfs_remove_domain_dir(struct irq_domain *d)
+{
+	debugfs_remove(d->debugfs_file);
+}
+
+void __init irq_domain_debugfs_init(struct dentry *root)
+{
+	struct irq_domain *d;
+
+	domain_dir = debugfs_create_dir("domains", root);
+	if (!domain_dir)
+		return;
+
+	debugfs_create_file("default", 0444, domain_dir, NULL, &dfs_domain_ops);
+	mutex_lock(&irq_domain_mutex);
+	list_for_each_entry(d, &irq_domain_list, link)
+		debugfs_add_domain_dir(d);
+	mutex_unlock(&irq_domain_mutex);
+}
+#endif