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int __init gic_of_init(struct device_node *node, struct device_node *parent){	gic_init_bases(dist_base, rdist_regs, nr_redist_regions, redist_stride, &node->fwnode);	=>int __init gic_init_bases(void __iomem *dist_base,				 struct redist_region *rdist_regs,				 u32 nr_redist_regions,				 u64 redist_stride,				 struct fwnode_handle *handle)	{		gic_data.fwnode = handle;		gic_data.dist_base = dist_base;		gic_data.redist_regions = rdist_regs;		gic_data.nr_redist_regions = nr_redist_regions;		gic_data.redist_stride = redist_stride;		==>static struct gic_chip_data gic_data __read_mostly;				/* 下面是读硬件, 获取支持中断的个数 */		/*		 * Find out how many interrupts are supported.		 * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)		 */		typer = readl_relaxed(gic_data.dist_base + GICD_TYPER);		gic_data.rdists.id_bits = GICD_TYPER_ID_BITS(typer);		gic_irqs = GICD_TYPER_IRQS(typer);		if (gic_irqs > 1020)			gic_irqs = 1020;		gic_data.irq_nr = gic_irqs;				/* 创建中断控制器对应的域 */		gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops, &gic_data);		==>static const struct irq_domain_ops gic_irq_domain_ops = {			.translate = gic_irq_domain_translate,			.alloc = gic_irq_domain_alloc,			.free = gic_irq_domain_free,			.select = gic_irq_domain_select,		};		=>struct irq_domain *irq_domain_create_tree(struct fwnode_handle *fwnode,					 const struct irq_domain_ops *ops,					 void *host_data)		{			return __irq_domain_add(fwnode, 0, ~0, 0, ops, host_data);			=>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 (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;					}				} 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;				}								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;			}		}				set_handle_irq(gic_handle_irq);		void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))		{			if (handle_arch_irq)				return;			handle_arch_irq = handle_irq;		}	}}

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