Linux内核笔记之中断映射

int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
   bool lookup, struct pt_regs *regs)
{
...
#ifdef CONFIG_IRQ_DOMAIN
 if (lookup)
  irq = irq_find_mapping(domain, hwirq);   ---- 获得虚拟中断号
#endif
...
}

struct irq_domain {
        struct list_head link;
        const char *name;
        const struct irq_domain_ops *ops;
        void *host_data;
        unsigned int flags;
        unsigned int mapcount;

        /* Optional data */
        struct fwnode_handle *fwnode;
        enum irq_domain_bus_token bus_token;
        struct irq_domain_chip_generic *gc;
#ifdef  CONFIG_IRQ_DOMAIN_HIERARCHY
        struct irq_domain *parent;
#endif
#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
        struct dentry           *debugfs_file;
#endif

        /* reverse map data. The linear map gets appended to the irq_domain */
        irq_hw_number_t hwirq_max;
        unsigned int revmap_direct_max_irq;
        unsigned int revmap_size;
        struct radix_tree_root revmap_tree;
        struct mutex revmap_tree_mutex;
        unsigned int linear_revmap[];
};

irq_domain_add_linear

irq_domain_add_tree

irq_domain_add_nomap

+-> gic_of_init
 +-> gic_init_bases
  +-> irq_domain_add_linear
   +-> _irq_domain_add

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 (WARN_ON(!domain))
  return NULL;
 ...
 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;
}

unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
{
 struct of_phandle_args oirq;

 if (of_irq_parse_one(dev, index, &oirq))
  return 0;

 return irq_create_of_mapping(&oirq);
}

+-> irq_create_of_mapping
 +->irq_create_fwspec_mapping
  +-> irq_find_matching_fwspec // 找到device node对应的irq_domain, 每一个irq_domain都定义了一系列的映射相关的方法
  +-> irq_domain_translate //解析中断信息，如硬件中断号， 中断出发类型
   +-> domain->ops->translate (gic_irq_domain_translate)
  +-> irq_create_mapping // 映射硬件中断号到虚拟中断号
   +-> irq_domain_alloc_descs // 分配一个虚拟中断号 从allocated_irq位图中取第一个空闲的bit位作为虚拟中断号
    +-> irq_domain_alloc_irqs_hierarchy
     +-> domain->ops->alloc (gic_irq_domain_alloc)
      +-> gic_irq_domain_map // gic创建硬中断和虚拟中断号的映射，并且根据中断类型设置struct irq_desc->handle_irq处理函数
   +-> irq_domain_associate
     +-> domain->ops->map 

+->gic_irq_domain_map 
 +-> irq_domain_set_info
  +-> irq_domain_set_hwirq_and_chip

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;
}