注册中断：对每一个pin进行循环遍历for (pin_num = 0; pin_num < min_t(int, ZYNQ_GPIO_NR_GPIOS,  (int)chip->ngpio); pin_num++)node

gpio_irq = irq_find_mapping(irq_domain, pin_num); 将GPIO号映射为Linux系统中断号。app

在Linux中断系统中，一个irq_domain表示一个中断控制器，其内中断由0开始编号(尚存在疑问)dom

unsigned int irq_find_mapping(struct irq_domain *domain, irq_hw_number_t hwirq)函数

将一个中断控制器上的某个硬件中断映射为某个Linux系统中断。this

/**

* struct irq_domain - Hardware interrupt number translation object

* @link: Element in global irq_domain list.

* @name: Name of interrupt domain

* @ops: pointer to irq_domain methods

* @host_data: private data pointer for use by owner. Not touched by irq_domain

* core code.

*

* Optional elements

* @of_node: Pointer to device tree nodes associated with the irq_domain. Used

* when decoding device tree interrupt specifiers.

* @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.

*

* Revmap data, used internally by irq_domain

* @revmap_direct_max_irq: The largest hwirq that can be set for controllers that

* support direct mapping

* @revmap_size: Size of the linear map table @linear_revmap[]

* @revmap_tree: Radix map tree for hwirqs that don't fit in the linear map

* @linear_revmap: Linear table of hwirq->virq reverse mappings

*/

struct irq_domain {

struct list_head link;

const char *name;

const struct irq_domain_ops *ops;

void *host_data;

/* Optional data */

struct device_node *of_node;

struct irq_domain_chip_generic *gc;

/* 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;

unsigned int linear_revmap[];

};

revmap_direct_max_irq: 小于该值的中断，Linux中断号和硬件中断号相同，直接返回。spa

revmap_size: 线性反向映射(彷佛要求域内IRQ从零开始，有点矛盾)，小于该值的hwirq直接利用linear_revmap作查找。code

不然用radix tree来查找映射。orm

irq_set_chip_and_handler(gpio_irq, &zynq_gpio_irqchip, handle_simple_irq);

ip

调用irq_get_desc_lock(irq, &flags, 0);，获取irq对应的irq_desc。并设定irq_desc的chip：desc->irq_data.chip = chip;ci

调用irq_reserve_irq(irq);，将allocated_irqs中断位图中相应的中断标识为已占用。

调用__irq_set_handler，将irq_desc中的handle_irq设定：desc->handle_irq = handle;

irq_set_chip_data(gpio_irq, (void *)gpio);

这个比较简单，将要用私有的变量关联到irq，desc->irq_data.chip_data = data;

set_irq_flags(gpio_irq, IRQF_VALID);

整体调用：

irq_set_handler_data(irq_num, (void *)gpio);

这里的irq_num是经过irq_num = platform_get_irq(pdev, 0);获取的系统配置文件里面的irq配置。这个函数也简单，实质为：desc->irq_data.handler_data = data;

irq_set_chained_handler(irq_num, zynq_gpio_irqhandler);

这个函数实质为：desc->handle_irq = handle;

最终调用关系为：调用zynq_gpio_irqhandler，而后在该函数中经过调用generic_handle_irq来调用最终的handle_simple_irq。