text: // SPDX-License-Identifier: GPL-2.0
  
  #define pr_fmt(fmt)  "irq: " fmt
  
  #include <linux/acpi.h>
  #include <linux/debugfs.h>
  #include <linux/hardirq.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/irqdesc.h>
  #include <linux/irqdomain.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  #include <linux/of_irq.h>
  #include <linux/topology.h>
  #include <linux/seq_file.h>
  #include <linux/slab.h>
  #include <linux/smp.h>
  #include <linux/fs.h>
  
  static LIST_HEAD(irq_domain_list);
  static DEFINE_MUTEX(irq_domain_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;
  	unsigned int		type;
  	char			*name;
  	phys_addr_t		*pa;
  };
  
  #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
   * @type:	Type of irqchip_fwnode. See linux/irqdomain.h
   * @id:		Optional user provided id if name != NULL
   * @name:	Optional user provided domain name
   * @pa:		Optional user-provided physical address
   *
   * 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(unsigned int type, int id,
  						const char *name,
  						phys_addr_t *pa)
  {
  	struct irqchip_fwid *fwid;
  	char *n;
  
  	fwid = kzalloc(sizeof(*fwid), GFP_KERNEL);
  
  	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@%pa", pa);
  		break;
  	}
  
  	if (!fwid || !n) {
  		kfree(fwid);
  		kfree(n);
  		return NULL;
  	}
  
  	fwid->type = type;
  	fwid->name = n;
  	fwid->pa = pa;
  	fwid->fwnode.ops = &irqchip_fwnode_ops;
  	return &fwid->fwnode;
  }
  EXPORT_SYMBOL_GPL(__irq_domain_alloc_fwnode);
  
  /**
   * irq_domain_free_fwnode - Free a non-OF-backed fwnode_handle
   *
   * Free a fwnode_handle allocated with irq_domain_alloc_fwnode.
   */
  void irq_domain_free_fwnode(struct fwnode_handle *fwnode)
  {
  	struct irqchip_fwid *fwid;
  
  	if (WARN_ON(!is_fwnode_irqchip(fwnode)))
  		return;
  
  	fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
  	kfree(fwid->name);
  	kfree(fwid);
  }
  EXPORT_SYMBOL_GPL(irq_domain_free_fwnode);
  
  /**
   * __irq_domain_add() - Allocate a new irq_domain data structure
   * @fwnode: firmware node for the interrupt controller
   * @size: Size of linear map; 0 for radix mapping only
   * @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: domain callbacks
   * @host_data: Controller private data pointer
   *
   * Allocates and initializes an irq_domain structure.
   * Returns pointer to IRQ domain, or NULL on failure.
   */
  struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
  				    irq_hw_number_t hwirq_max, int direct_max,
  				    const struct irq_domain_ops *ops,
  				    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 (!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->fwnode = fwnode;
  			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 = kasprintf(GFP_KERNEL, "%pOF", of_node);
  		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->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);
  
  	pr_debug("Added domain %s\n", domain->name);
  	return domain;
  }
  EXPORT_SYMBOL_GPL(__irq_domain_add);
  
  /**
   * irq_domain_remove() - Remove an irq domain.
   * @domain: domain to remove
   *
   * This routine is used to remove an irq domain. The caller must ensure
   * that all mappings within the domain have been disposed of prior to
   * use, depending on the revmap type.
   */
  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));
  
  	list_del(&domain->link);
  
  	/*
  	 * If the going away domain is the default one, reset it.
  	 */
  	if (unlikely(irq_default_domain == domain))
  		irq_set_default_host(NULL);
  
  	mutex_unlock(&irq_domain_mutex);
  
  	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.
   * @size: total number of irqs in mapping
   * @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: domain callbacks
   * @host_data: Controller private data pointer
   *
   * Allocates an irq_domain, and optionally if first_irq is positive then also
   * allocate irq_descs and map all of the hwirqs to virqs starting at first_irq.
   *
   * This is intended to implement the expected behaviour for most
   * interrupt controllers. If device tree is used, then first_irq will be 0 and
   * irqs get mapped dynamically on the fly. However, if the controller requires
   * static virq assignments (non-DT boot) then it will set that up correctly.
   */
  struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
  					 unsigned int size,
  					 unsigned int first_irq,
  					 const struct irq_domain_ops *ops,
  					 void *host_data)
  {
  	struct irq_domain *domain;
  
  	domain = __irq_domain_add(of_node_to_fwnode(of_node), size, size, 0, ops, host_data);
  	if (!domain)
  		return NULL;
  
  	if (first_irq > 0) {
  		if (IS_ENABLED(CONFIG_SPARSE_IRQ)) {
  			/* attempt to allocated irq_descs */
  			int rc = irq_alloc_descs(first_irq, first_irq, size,
  						 of_node_to_nid(of_node));
  			if (rc < 0)
  				pr_info("Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
  					first_irq);
  		}
  		irq_domain_associate_many(domain, first_irq, 0, size);
  	}
  
  	return domain;
  }
  EXPORT_SYMBOL_GPL(irq_domain_add_simple);
  
  /**
   * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.
   * @of_node: pointer to interrupt controller's device tree node.
   * @size: total number of irqs in legacy mapping
   * @first_irq: first number of irq block assigned to the domain
   * @first_hwirq: first hwirq number to use for the translation. Should normally
   *               be '0', but a positive integer can be used if the effective
   *               hwirqs numbering does not begin at zero.
   * @ops: map/unmap domain callbacks
   * @host_data: Controller private data pointer
   *
   * Note: the map() callback will be called before this function returns
   * for all legacy interrupts except 0 (which is always the invalid irq for
   * a legacy controller).
   */
  struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
  					 unsigned int size,
  					 unsigned int first_irq,
  					 irq_hw_number_t first_hwirq,
  					 const struct irq_domain_ops *ops,
  					 void *host_data)
  {
  	struct irq_domain *domain;
  
  	domain = __irq_domain_add(of_node_to_fwnode(of_node), first_hwirq + size,
  				  first_hwirq + size, 0, ops, host_data);
  	if (domain)
  		irq_domain_associate_many(domain, first_irq, first_hwirq, size);
  
  	return domain;
  }
  EXPORT_SYMBOL_GPL(irq_domain_add_legacy);
  
  /**
   * irq_find_matching_fwspec() - Locates a domain for a given fwspec
   * @fwspec: FW specifier for an interrupt
   * @bus_token: domain-specific data
   */
  struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
  					    enum irq_domain_bus_token bus_token)
  {
  	struct irq_domain *h, *found = NULL;
  	struct fwnode_handle *fwnode = fwspec->fwnode;
  	int rc;
  
  	/* We might want to match the legacy controller last since
  	 * it might potentially be set to match all interrupts in
  	 * the absence of a device node. This isn't a problem so far
  	 * yet though...
  	 *
  	 * bus_token == DOMAIN_BUS_ANY matches any domain, any other
  	 * values must generate an exact match for the domain to be
  	 * selected.
  	 */
  	mutex_lock(&irq_domain_mutex);
  	list_for_each_entry(h, &irq_domain_list, link) {
  		if (h->ops->select && fwspec->param_count)
  			rc = h->ops->select(h, fwspec, bus_token);
  		else if (h->ops->match)
  			rc = h->ops->match(h, to_of_node(fwnode), bus_token);
  		else
  			rc = ((fwnode != NULL) && (h->fwnode == fwnode) &&
  			      ((bus_token == DOMAIN_BUS_ANY) ||
  			       (h->bus_token == bus_token)));
  
  		if (rc) {
  			found = h;
  			break;
  		}
  	}
  	mutex_unlock(&irq_domain_mutex);
  	return found;
  }
  EXPORT_SYMBOL_GPL(irq_find_matching_fwspec);
  
  /**
   * irq_domain_check_msi_remap - Check whether all MSI irq domains implement
   * IRQ remapping
   *
   * Return: false if any MSI irq domain does not support IRQ remapping,
   * true otherwise (including if there is no MSI irq domain)
   */
  bool irq_domain_check_msi_remap(void)
  {
  	struct irq_domain *h;
  	bool ret = true;
  
  	mutex_lock(&irq_domain_mutex);
  	list_for_each_entry(h, &irq_domain_list, link) {
  		if (irq_domain_is_msi(h) &&
  		    !irq_domain_hierarchical_is_msi_remap(h)) {
  			ret = false;
  			break;
  		}
  	}
  	mutex_unlock(&irq_domain_mutex);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap);
  
  /**
   * irq_set_default_host() - Set a "default" irq domain
   * @domain: default domain pointer
   *
   * For convenience, it's possible to set a "default" domain that will be used
   * whenever NULL is passed to irq_create_mapping(). It makes life easier for
   * platforms that want to manipulate a few hard coded interrupt numbers that
   * aren't properly represented in the device-tree.
   */
  void irq_set_default_host(struct irq_domain *domain)
  {
  	pr_debug("Default domain set to @0x%p\n", domain);
  
  	irq_default_domain = domain;
  }
  EXPORT_SYMBOL_GPL(irq_set_default_host);
  
  /**
   * irq_get_default_host() - Retrieve the "default" irq domain
   *
   * Returns: the default domain, if any.
   *
   * Modern code should never use this. This should only be used on
   * systems that cannot implement a firmware->fwnode mapping (which
   * both DT and ACPI provide).
   */
  struct irq_domain *irq_get_default_host(void)
  {
  	return irq_default_domain;
  }
  
  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);
  	irq_hw_number_t hwirq;
  
  	if (WARN(!irq_data || irq_data->domain != domain,
  		 "virq%i doesn't exist; cannot disassociate\n", irq))
  		return;
  
  	hwirq = irq_data->hwirq;
  	irq_set_status_flags(irq, IRQ_NOREQUEST);
  
  	/* remove chip and handler */
  	irq_set_chip_and_handler(irq, NULL, NULL);
  
  	/* Make sure it's completed */
  	synchronize_irq(irq);
  
  	/* Tell the PIC about it */
  	if (domain->ops->unmap)
  		domain->ops->unmap(domain, irq);
  	smp_mb();
  
  	irq_data->domain = NULL;
  	irq_data->hwirq = 0;
  	domain->mapcount--;
  
  	/* Clear reverse map for this hwirq */
  	irq_domain_clear_mapping(domain, hwirq);
  }
  
  int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
  			 irq_hw_number_t hwirq)
  {
  	struct irq_data *irq_data = irq_get_irq_data(virq);
  	int ret;
  
  	if (WARN(hwirq >= domain->hwirq_max,
  		 "error: hwirq 0x%x is too large for %s\n", (int)hwirq, domain->name))
  		return -EINVAL;
  	if (WARN(!irq_data, "error: virq%i is not allocated", virq))
  		return -EINVAL;
  	if (WARN(irq_data->domain, "error: virq%i is already associated", virq))
  		return -EINVAL;
  
  	mutex_lock(&irq_domain_mutex);
  	irq_data->hwirq = hwirq;
  	irq_data->domain = domain;
  	if (domain->ops->map) {
  		ret = domain->ops->map(domain, virq, hwirq);
  		if (ret != 0) {
  			/*
  			 * If map() returns -EPERM, this interrupt is protected
  			 * by the firmware or some other service and shall not
  			 * be mapped. Don't bother telling the user about it.
  			 */
  			if (ret != -EPERM) {
  				pr_info("%s didn't like hwirq-0x%lx to VIRQ%i mapping (rc=%d)\n",
  				       domain->name, hwirq, virq, ret);
  			}
  			irq_data->domain = NULL;
  			irq_data->hwirq = 0;
  			mutex_unlock(&irq_domain_mutex);
  			return ret;
  		}
  
  		/* If not already assigned, give the domain the chip's name */
  		if (!domain->name && irq_data->chip)
  			domain->name = irq_data->chip->name;
  	}
  
  	domain->mapcount++;
  	irq_domain_set_mapping(domain, hwirq, irq_data);
  	mutex_unlock(&irq_domain_mutex);
  
  	irq_clear_status_flags(virq, IRQ_NOREQUEST);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_domain_associate);
  
  void irq_domain_associate_many(struct irq_domain *domain, unsigned int irq_base,
  			       irq_hw_number_t hwirq_base, int count)
  {
  	struct device_node *of_node;
  	int i;
  
  	of_node = irq_domain_get_of_node(domain);
  	pr_debug("%s(%s, irqbase=%i, hwbase=%i, count=%i)\n", __func__,
  		of_node_full_name(of_node), irq_base, (int)hwirq_base, count);
  
  	for (i = 0; i < count; i++) {
  		irq_domain_associate(domain, irq_base + i, hwirq_base + i);
  	}
  }
  EXPORT_SYMBOL_GPL(irq_domain_associate_many);
  
  /**
   * irq_create_direct_mapping() - Allocate an irq for direct mapping
   * @domain: domain to allocate the irq for or NULL for default domain
   *
   * This routine is used for irq controllers which can choose the hardware
   * interrupt numbers they generate. In such a case it's simplest to use
   * the linux irq as the hardware interrupt number. It still uses the linear
   * or radix tree to store the mapping, but the irq controller can optimize
   * the revmap path by using the hwirq directly.
   */
  unsigned int irq_create_direct_mapping(struct irq_domain *domain)
  {
  	struct device_node *of_node;
  	unsigned int virq;
  
  	if (domain == NULL)
  		domain = irq_default_domain;
  
  	of_node = irq_domain_get_of_node(domain);
  	virq = irq_alloc_desc_from(1, of_node_to_nid(of_node));
  	if (!virq) {
  		pr_debug("create_direct virq allocation failed\n");
  		return 0;
  	}
  	if (virq >= domain->revmap_direct_max_irq) {
  		pr_err("ERROR: no free irqs available below %i maximum\n",
  			domain->revmap_direct_max_irq);
  		irq_free_desc(virq);
  		return 0;
  	}
  	pr_debug("create_direct obtained virq %d\n", virq);
  
  	if (irq_domain_associate(domain, virq, virq)) {
  		irq_free_desc(virq);
  		return 0;
  	}
  
  	return virq;
  }
  EXPORT_SYMBOL_GPL(irq_create_direct_mapping);
  
  /**
   * irq_create_mapping() - Map a hardware interrupt into linux irq space
   * @domain: domain owning this hardware interrupt or NULL for default domain
   * @hwirq: hardware irq number in that domain space
   *
   * Only one mapping per hardware interrupt is permitted. Returns a linux
   * irq number.
   * If the sense/trigger is to be specified, set_irq_type() should be called
   * on the number returned from that call.
   */
  unsigned int irq_create_mapping(struct irq_domain *domain,
  				irq_hw_number_t hwirq)
  {
  	struct device_node *of_node;
  	int virq;
  
  	pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
  
  	/* Look for default domain if nececssary */
  	if (domain == NULL)
  		domain = irq_default_domain;
  	if (domain == NULL) {
  		WARN(1, "%s(, %lx) called with NULL domain\n", __func__, hwirq);
  		return 0;
  	}
  	pr_debug("-> using domain @%p\n", domain);
  
  	of_node = irq_domain_get_of_node(domain);
  
  	/* Check if mapping already exists */
  	virq = irq_find_mapping(domain, hwirq);
  	if (virq) {
  		pr_debug("-> existing mapping on virq %d\n", virq);
  		return virq;
  	}
  
  	/* Allocate a virtual interrupt number */
  	virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node), NULL);
  	if (virq <= 0) {
  		pr_debug("-> virq allocation failed\n");
  		return 0;
  	}
  
  	if (irq_domain_associate(domain, virq, hwirq)) {
  		irq_free_desc(virq);
  		return 0;
  	}
  
  	pr_debug("irq %lu on domain %s mapped to virtual irq %u\n",
  		hwirq, of_node_full_name(of_node), virq);
  
  	return virq;
  }
  EXPORT_SYMBOL_GPL(irq_create_mapping);
  
  /**
   * irq_create_strict_mappings() - Map a range of hw irqs to fixed linux irqs
   * @domain: domain owning the interrupt range
   * @irq_base: beginning of linux IRQ range
   * @hwirq_base: beginning of hardware IRQ range
   * @count: Number of interrupts to map
   *
   * This routine is used for allocating and mapping a range of hardware
   * irqs to linux irqs where the linux irq numbers are at pre-defined
   * locations. For use by controllers that already have static mappings
   * to insert in to the domain.
   *
   * Non-linear users can use irq_create_identity_mapping() for IRQ-at-a-time
   * domain insertion.
   *
   * 0 is returned upon success, while any failure to establish a static
   * mapping is treated as an error.
   */
  int irq_create_strict_mappings(struct irq_domain *domain, unsigned int irq_base,
  			       irq_hw_number_t hwirq_base, int count)
  {
  	struct device_node *of_node;
  	int ret;
  
  	of_node = irq_domain_get_of_node(domain);
  	ret = irq_alloc_descs(irq_base, irq_base, count,
  			      of_node_to_nid(of_node));
  	if (unlikely(ret < 0))
  		return ret;
  
  	irq_domain_associate_many(domain, irq_base, hwirq_base, count);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_create_strict_mappings);
  
  static int irq_domain_translate(struct irq_domain *d,
  				struct irq_fwspec *fwspec,
  				irq_hw_number_t *hwirq, unsigned int *type)
  {
  #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
  	if (d->ops->translate)
  		return d->ops->translate(d, fwspec, hwirq, type);
  #endif
  	if (d->ops->xlate)
  		return d->ops->xlate(d, to_of_node(fwspec->fwnode),
  				     fwspec->param, fwspec->param_count,
  				     hwirq, type);
  
  	/* If domain has no translation, then we assume interrupt line */
  	*hwirq = fwspec->param[0];
  	return 0;
  }
  
  static void of_phandle_args_to_fwspec(struct device_node *np, const u32 *args,
  				      unsigned int count,
  				      struct irq_fwspec *fwspec)
  {
  	int i;
  
  	fwspec->fwnode = np ? &np->fwnode : NULL;
  	fwspec->param_count = count;
  
  	for (i = 0; i < count; i++)
  		fwspec->param[i] = args[i];
  }
  
  unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec)
  {
  	struct irq_domain *domain;
  	struct irq_data *irq_data;
  	irq_hw_number_t hwirq;
  	unsigned int type = IRQ_TYPE_NONE;
  	int virq;
  
  	if (fwspec->fwnode) {
  		domain = irq_find_matching_fwspec(fwspec, DOMAIN_BUS_WIRED);
  		if (!domain)
  			domain = irq_find_matching_fwspec(fwspec, DOMAIN_BUS_ANY);
  	} else {
  		domain = irq_default_domain;
  	}
  
  	if (!domain) {
  		pr_warn("no irq domain found for %s !\n",
  			of_node_full_name(to_of_node(fwspec->fwnode)));
  		return 0;
  	}
  
  	if (irq_domain_translate(domain, fwspec, &hwirq, &type))
  		return 0;
  
  	/*
  	 * WARN if the irqchip returns a type with bits
  	 * outside the sense mask set and clear these bits.
  	 */
  	if (WARN_ON(type & ~IRQ_TYPE_SENSE_MASK))
  		type &= IRQ_TYPE_SENSE_MASK;
  
  	/*
  	 * If we've already configured this interrupt,
  	 * don't do it again, or hell will break loose.
  	 */
  	virq = irq_find_mapping(domain, hwirq);
  	if (virq) {
  		/*
  		 * If the trigger type is not specified or matches the
  		 * current trigger type then we are done so return the
  		 * interrupt number.
  		 */
  		if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq))
  			return virq;
  
  		/*
  		 * If the trigger type has not been set yet, then set
  		 * it now and return the interrupt number.
  		 */
  		if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) {
  			irq_data = irq_get_irq_data(virq);
  			if (!irq_data)
  				return 0;
  
  			irqd_set_trigger_type(irq_data, type);
  			return virq;
  		}
  
  		pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n",
  			hwirq, of_node_full_name(to_of_node(fwspec->fwnode)));
  		return 0;
  	}
  
  	if (irq_domain_is_hierarchy(domain)) {
  		virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, fwspec);
  		if (virq <= 0)
  			return 0;
  	} else {
  		/* Create mapping */
  		virq = irq_create_mapping(domain, hwirq);
  		if (!virq)
  			return virq;
  	}
  
  	irq_data = irq_get_irq_data(virq);
  	if (!irq_data) {
  		if (irq_domain_is_hierarchy(domain))
  			irq_domain_free_irqs(virq, 1);
  		else
  			irq_dispose_mapping(virq);
  		return 0;
  	}
  
  	/* Store trigger type */
  	irqd_set_trigger_type(irq_data, type);
  
  	return virq;
  }
  EXPORT_SYMBOL_GPL(irq_create_fwspec_mapping);
  
  unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data)
  {
  	struct irq_fwspec fwspec;
  
  	of_phandle_args_to_fwspec(irq_data->np, irq_data->args,
  				  irq_data->args_count, &fwspec);
  
  	return irq_create_fwspec_mapping(&fwspec);
  }
  EXPORT_SYMBOL_GPL(irq_create_of_mapping);
  
  /**
   * irq_dispose_mapping() - Unmap an interrupt
   * @virq: linux irq number of the interrupt to unmap
   */
  void irq_dispose_mapping(unsigned int virq)
  {
  	struct irq_data *irq_data = irq_get_irq_data(virq);
  	struct irq_domain *domain;
  
  	if (!virq || !irq_data)
  		return;
  
  	domain = irq_data->domain;
  	if (WARN_ON(domain == NULL))
  		return;
  
  	if (irq_domain_is_hierarchy(domain)) {
  		irq_domain_free_irqs(virq, 1);
  	} else {
  		irq_domain_disassociate(domain, virq);
  		irq_free_desc(virq);
  	}
  }
  EXPORT_SYMBOL_GPL(irq_dispose_mapping);
  
  /**
   * irq_find_mapping() - Find a linux irq from a hw irq number.
   * @domain: domain owning this hardware interrupt
   * @hwirq: hardware irq number in that domain space
   */
  unsigned int irq_find_mapping(struct irq_domain *domain,
  			      irq_hw_number_t hwirq)
  {
  	struct irq_data *data;
  
  	/* Look for default domain if nececssary */
  	if (domain == NULL)
  		domain = irq_default_domain;
  	if (domain == NULL)
  		return 0;
  
  	if (hwirq < domain->revmap_direct_max_irq) {
  		data = irq_domain_get_irq_data(domain, hwirq);
  		if (data && data->hwirq == hwirq)
  			return hwirq;
  	}
  
  	/* Check if the hwirq is in the linear revmap. */
  	if (hwirq < domain->revmap_size)
  		return domain->linear_revmap[hwirq];
  
  	rcu_read_lock();
  	data = radix_tree_lookup(&domain->revmap_tree, hwirq);
  	rcu_read_unlock();
  	return data ? data->irq : 0;
  }
  EXPORT_SYMBOL_GPL(irq_find_mapping);
  
  /**
   * irq_domain_xlate_onecell() - Generic xlate for direct one cell bindings
   *
   * Device Tree IRQ specifier translation function which works with one cell
   * bindings where the cell value maps directly to the hwirq number.
   */
  int irq_domain_xlate_onecell(struct irq_domain *d, struct device_node *ctrlr,
  			     const u32 *intspec, unsigned int intsize,
  			     unsigned long *out_hwirq, unsigned int *out_type)
  {
  	if (WARN_ON(intsize < 1))
  		return -EINVAL;
  	*out_hwirq = intspec[0];
  	*out_type = IRQ_TYPE_NONE;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_domain_xlate_onecell);
  
  /**
   * irq_domain_xlate_twocell() - Generic xlate for direct two cell bindings
   *
   * Device Tree IRQ specifier translation function which works with two cell
   * bindings where the cell values map directly to the hwirq number
   * and linux irq flags.
   */
  int irq_domain_xlate_twocell(struct irq_domain *d, struct device_node *ctrlr,
  			const u32 *intspec, unsigned int intsize,
  			irq_hw_number_t *out_hwirq, unsigned int *out_type)
  {
  	struct irq_fwspec fwspec;
  
  	of_phandle_args_to_fwspec(ctrlr, intspec, intsize, &fwspec);
  	return irq_domain_translate_twocell(d, &fwspec, out_hwirq, out_type);
  }
  EXPORT_SYMBOL_GPL(irq_domain_xlate_twocell);
  
  /**
   * irq_domain_xlate_onetwocell() - Generic xlate for one or two cell bindings
   *
   * Device Tree IRQ specifier translation function which works with either one
   * or two cell bindings where the cell values map directly to the hwirq number
   * and linux irq flags.
   *
   * Note: don't use this function unless your interrupt controller explicitly
   * supports both one and two cell bindings.  For the majority of controllers
   * the _onecell() or _twocell() variants above should be used.
   */
  int irq_domain_xlate_onetwocell(struct irq_domain *d,
  				struct device_node *ctrlr,
  				const u32 *intspec, unsigned int intsize,
  				unsigned long *out_hwirq, unsigned int *out_type)
  {
  	if (WARN_ON(intsize < 1))
  		return -EINVAL;
  	*out_hwirq = intspec[0];
  	if (intsize > 1)
  		*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
  	else
  		*out_type = IRQ_TYPE_NONE;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_domain_xlate_onetwocell);
  
  const struct irq_domain_ops irq_domain_simple_ops = {
  	.xlate = irq_domain_xlate_onetwocell,
  };
  EXPORT_SYMBOL_GPL(irq_domain_simple_ops);
  
  /**
   * irq_domain_translate_onecell() - Generic translate for direct one cell
   * bindings
   */
  int irq_domain_translate_onecell(struct irq_domain *d,
  				 struct irq_fwspec *fwspec,
  				 unsigned long *out_hwirq,
  				 unsigned int *out_type)
  {
  	if (WARN_ON(fwspec->param_count < 1))
  		return -EINVAL;
  	*out_hwirq = fwspec->param[0];
  	*out_type = IRQ_TYPE_NONE;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_domain_translate_onecell);
  
  /**
   * irq_domain_translate_twocell() - Generic translate for direct two cell
   * bindings
   *
   * Device Tree IRQ specifier translation function which works with two cell
   * bindings where the cell values map directly to the hwirq number
   * and linux irq flags.
   */
  int irq_domain_translate_twocell(struct irq_domain *d,
  				 struct irq_fwspec *fwspec,
  				 unsigned long *out_hwirq,
  				 unsigned int *out_type)
  {
  	if (WARN_ON(fwspec->param_count < 2))
  		return -EINVAL;
  	*out_hwirq = fwspec->param[0];
  	*out_type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(irq_domain_translate_twocell);
  
  int irq_domain_alloc_descs(int virq, unsigned int cnt, irq_hw_number_t hwirq,
  			   int node, const struct irq_affinity_desc *affinity)
  {
  	unsigned int hint;
  
  	if (virq >= 0) {
  		virq = __irq_alloc_descs(virq, virq, cnt, node, THIS_MODULE,
  					 affinity);
  	} else {
  		hint = hwirq % nr_irqs;
  		if (hint == 0)
  			hint++;
  		virq = __irq_alloc_descs(-1, hint, cnt, node, THIS_MODULE,
  					 affinity);
  		if (virq <= 0 && hint > 1) {
  			virq = __irq_alloc_descs(-1, 1, cnt, node, THIS_MODULE,
  						 affinity);
  		}
  	}
  
  	return virq;
  }
  
  #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
  /**
   * irq_domain_create_hierarchy - Add a irqdomain into the hierarchy
   * @parent:	Parent irq domain to associate with the new domain
   * @flags:	Irq domain flags associated to the domain
   * @size:	Size of the domain. See below
   * @fwnode:	Optional fwnode of the interrupt controller
   * @ops:	Pointer to the interrupt domain callbacks
   * @host_data:	Controller private data pointer
   *
   * If @size is 0 a tree domain is created, otherwise a linear domain.
   *
   * If successful the parent is associated to the new domain and the
   * domain flags are set.
   * Returns pointer to IRQ domain, or NULL on failure.
   */
  struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
  					    unsigned int flags,
  					    unsigned int size,
  					    struct fwnode_handle *fwnode,
  					    const struct irq_domain_ops *ops,
  					    void *host_data)
  {
  	struct irq_domain *domain;
  
  	if (size)
  		domain = irq_domain_create_linear(fwnode, size, ops, host_data);
  	else
  		domain = irq_domain_create_tree(fwnode, ops, host_data);
  	if (domain) {
  		domain->parent = parent;
  		domain->flags |= flags;
  	}
  
  	return domain;
  }
  EXPORT_SYMBOL_GPL(irq_domain_create_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;
  
  		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)
  			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;
  
  		domain->mapcount--;
  		irq_domain_clear_mapping(domain, hwirq);
  	}
  }
  
  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,
  				irq_data_get_node(child));
  	if (irq_data) {
  		child->parent_data = irq_data;
  		irq_data->irq = child->irq;
  		irq_data->common = child->common;
  		irq_data->domain = domain;
  	}
  
  	return irq_data;
  }
  
  static void irq_domain_free_irq_data(unsigned int virq, unsigned int nr_irqs)
  {
  	struct irq_data *irq_data, *tmp;
  	int i;
  
  	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)
  {
  	struct irq_data *irq_data;
  	struct irq_domain *parent;
  	int i;
  
  	/* 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;
  }
  EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
  
  /**
   * irq_domain_set_hwirq_and_chip - Set hwirq and irqchip of @virq at @domain
   * @domain:	Interrupt domain to match
   * @virq:	IRQ number
   * @hwirq:	The hwirq number
   * @chip:	The associated interrupt chip
   * @chip_data:	The associated chip data
   */
  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;
  }
  EXPORT_SYMBOL_GPL(irq_domain_set_hwirq_and_chip);
  
  /**
   * irq_domain_set_info - Set the complete data for a @virq in @domain
   * @domain:		Interrupt domain to match
   * @virq:		IRQ number
   * @hwirq:		The hardware interrupt number
   * @chip:		The associated interrupt chip
   * @chip_data:		The associated interrupt chip data
   * @handler:		The interrupt flow handler
   * @handler_data:	The interrupt flow handler data
   * @handler_name:	The interrupt handler name
   */
  void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
  			 irq_hw_number_t hwirq, struct irq_chip *chip,
  			 void *chip_data, irq_flow_handler_t handler,
  			 void *handler_data, const char *handler_name)
  {
  	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, chip, chip_data);
  	__irq_set_handler(virq, handler, 0, handler_name);
  	irq_set_handler_data(virq, handler_data);
  }
  EXPORT_SYMBOL(irq_domain_set_info);
  
  /**
   * irq_domain_reset_irq_data - Clear hwirq, chip and chip_data in @irq_data
   * @irq_data:	The pointer to irq_data
   */
  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;
  }
  EXPORT_SYMBOL_GPL(irq_domain_reset_irq_data);
  
  /**
   * irq_domain_free_irqs_common - Clear irq_data and free the parent
   * @domain:	Interrupt domain to match
   * @virq:	IRQ number to start with
   * @nr_irqs:	The number of irqs to free
   */
  void irq_domain_free_irqs_common(struct irq_domain *domain, unsigned int virq,
  				 unsigned int nr_irqs)
  {
  	struct irq_data *irq_data;
  	int i;
  
  	for (i = 0; i < nr_irqs; i++) {
  		irq_data = irq_domain_get_irq_data(domain, virq + i);
  		if (irq_data)
  			irq_domain_reset_irq_data(irq_data);
  	}
  	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
  }
  EXPORT_SYMBOL_GPL(irq_domain_free_irqs_common);
  
  /**
   * irq_domain_free_irqs_top - Clear handler and handler data, clear irqdata and free parent
   * @domain:	Interrupt domain to match
   * @virq:	IRQ number to start with
   * @nr_irqs:	The number of irqs to free
   */
  void irq_domain_free_irqs_top(struct irq_domain *domain, unsigned int virq,
  			      unsigned int nr_irqs)
  {
  	int i;
  
  	for (i = 0; i < nr_irqs; i++) {
  		irq_set_handler_data(virq + i, NULL);
  		irq_set_handler(virq + i, NULL);
  	}
  	irq_domain_free_irqs_common(domain, virq, nr_irqs);
  }
  
  static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
  					   unsigned int irq_base,
  					   unsigned int nr_irqs)
  {
  	if (domain->ops->free)
  		domain->ops->free(domain, irq_base, nr_irqs);
  }
  
  int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
  				    unsigned int irq_base,
  				    unsigned int nr_irqs, void *arg)
  {
  	if (!domain->ops->alloc) {
  		pr_debug("domain->ops->alloc() is NULL\n");
  		return -ENOSYS;
  	}
  
  	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
  }
  
  /**
   * __irq_domain_alloc_irqs - Allocate IRQs from domain
   * @domain:	domain to allocate from
   * @irq_base:	allocate specified IRQ number 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
   * @affinity:	Optional irq affinity mask for multiqueue devices
   *
   * Allocate IRQ numbers and initialized all data structures to support
   * hierarchy 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, const struct irq_affinity_desc *affinity)
  {
  	int i, ret, virq;
  
  	if (domain == NULL) {
  		domain = irq_default_domain;
  		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
  			return -EINVAL;
  	}
  
  	if (realloc && irq_base >= 0) {
  		virq = irq_base;
  	} else {
  		virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node,
  					      affinity);
  		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 = irq_domain_alloc_irqs_hierarchy(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;
  }
  
  /* 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;
  		kfree(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
   * @nr_irqs:	number of IRQs to free
   */
  void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
  {
  	struct irq_data *data = irq_get_irq_data(virq);
  	int i;
  
  	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);
  	irq_domain_free_irqs_hierarchy(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_alloc_irqs_parent - Allocate interrupts from parent domain
   * @irq_base:	Base IRQ number
   * @nr_irqs:	Number of IRQs to allocate
   * @arg:	Allocation data (arch/domain specific)
   *
   * Check whether the domain has been setup recursive. If not allocate
   * through the parent domain.
   */
  int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
  				 unsigned int irq_base, unsigned int nr_irqs,
  				 void *arg)
  {
  	if (!domain->parent)
  		return -ENOSYS;
  
  	return irq_domain_alloc_irqs_hierarchy(domain->parent, irq_base,
  					       nr_irqs, arg);
  }
  EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
  
  /**
   * irq_domain_free_irqs_parent - Free interrupts from parent domain
   * @irq_base:	Base IRQ number
   * @nr_irqs:	Number of IRQs to free
   *
   * Check whether the domain has been setup recursive. If not free
   * through the parent domain.
   */
  void irq_domain_free_irqs_parent(struct irq_domain *domain,
  				 unsigned int irq_base, unsigned int 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_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_deactivate_irq(irq_data->parent_data);
  	}
  }
  
  static int __irq_domain_activate_irq(struct irq_data *irqd, bool reserve)
  {
  	int ret = 0;
  
  	if (irqd && irqd->domain) {
  		struct irq_domain *domain = irqd->domain;
  
  		if (irqd->parent_data)
  			ret = __irq_domain_activate_irq(irqd->parent_data,
  							reserve);
  		if (!ret && domain->ops->activate) {
  			ret = domain->ops->activate(domain, irqd, reserve);
  			/* Rollback in case of error */
  			if (ret && irqd->parent_data)
  				__irq_domain_deactivate_irq(irqd->parent_data);
  		}
  	}
  	return ret;
  }
  
  /**
   * irq_domain_activate_irq - Call domain_ops->activate recursively to activate
   *			     interrupt
   * @irq_data:	Outermost irq_data associated with interrupt
   * @reserve:	If set only reserve an interrupt vector instead of assigning one
   *
   * 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, bool reserve)
  {
  	int ret = 0;
  
  	if (!irqd_is_activated(irq_data))
  		ret = __irq_domain_activate_irq(irq_data, reserve);
  	if (!ret)
  		irqd_set_activated(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.
   */
  void irq_domain_deactivate_irq(struct irq_data *irq_data)
  {
  	if (irqd_is_activated(irq_data)) {
  		__irq_domain_deactivate_irq(irq_data);
  		irqd_clr_activated(irq_data);
  	}
  }
  
  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;
  }
  
  /**
   * irq_domain_hierarchical_is_msi_remap - Check if the domain or any
   * parent has MSI remapping support
   * @domain: domain pointer
   */
  bool irq_domain_hierarchical_is_msi_remap(struct irq_domain *domain)
  {
  	for (; domain; domain = domain->parent) {
  		if (irq_domain_is_msi_remap(domain))
  			return true;
  	}
  	return false;
  }
  #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;
  }
  EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
  
  /**
   * irq_domain_set_info - Set the complete data for a @virq in @domain
   * @domain:		Interrupt domain to match
   * @virq:		IRQ number
   * @hwirq:		The hardware interrupt number
   * @chip:		The associated interrupt chip
   * @chip_data:		The associated interrupt chip data
   * @handler:		The interrupt flow handler
   * @handler_data:	The interrupt flow handler data
   * @handler_name:	The interrupt handler name
   */
  void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
  			 irq_hw_number_t hwirq, struct irq_chip *chip,
  			 void *chip_data, irq_flow_handler_t handler,
  			 void *handler_data, const char *handler_name)
  {
  	irq_set_chip_and_handler_name(virq, chip, handler, handler_name);
  	irq_set_chip_data(virq, chip_data);
  	irq_set_handler_data(virq, handler_data);
  }
  
  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;
  }
  DEFINE_SHOW_ATTRIBUTE(irq_domain_debug);
  
  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,
  					      &irq_domain_debug_fops);
  }
  
  static void debugfs_remove_domain_dir(struct irq_domain *d)
  {
  	debugfs_remove(d->debugfs_file);
  	d->debugfs_file = NULL;
  }
  
  void __init irq_domain_debugfs_init(struct dentry *root)
  {
  	struct irq_domain *d;
  
  	domain_dir = debugfs_create_dir("domains", root);
  
  	debugfs_create_file("default", 0444, domain_dir, NULL,
  			    &irq_domain_debug_fops);
  	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
  