Request_irq和setup_irq的区别.docVIP

Linux 内核提供了两个注册中断处理函数的接口：setup_irq和request_irq。这两个函数都定义在kernel/irq/manage.c里。 /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. */ int setup_irq(unsigned int irq, struct irqaction *new); /* * request_irq - allocate an interrupt line * This call allocates interrupt resources and enables the * interrupt line and IRQ handling. */ int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *), unsigned long irqflags, const char *devname, void *dev_id) 这两个函数有什么样的区别呢？ 先看看setup_irq Setup_irq通常用在系统时钟(GP Timer)驱动里，注册系统时钟驱动的中断处理函数。 下面举个列子, 如s3c2410 timer驱动： /* arch/arm/mach-s3c2410/time.c */ static struct irqaction s3c2410_timer_irq = { .name = S3C2410 Timer Tick, .flags = IRQF_DISABLED | IRQF_TIMER, .handler = s3c2410_timer_interrupt, }; static void __init s3c2410_timer_init (void) { s3c2410_timer_setup(); setup_irq(IRQ_TIMER4, s3c2410_timer_irq); } struct sys_timer s3c24xx_timer = { .init = s3c2410_timer_init, .offset = s3c2410_gettimeoffset, .resume = s3c2410_timer_setup }; struct sys_timer s3c24xx_timer = { .init = s3c2410_timer_init, .offset = s3c2410_gettimeoffset, .resume = s3c2410_timer_setup }; 可以看到，setup_irq的使用流程很简单。首先定义s3c2410 timer驱动的irqaction结构体，该结构体用于描述timer中断的基本属性包括中断名、类别以及该中断handler等。然后通过setup_irq函数将timer的irqaction注册进内核。其中，IRQ_TIMER4为s3c2410 timer的中断号。 再看看request_irq request_irq源码如下： /* kernel/irq/manage.c */ int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *), unsigned long irqflags, const char *devname, void *dev_id) { struct irqaction *action; int retval; #ifdef CONFIG_LOCKDEP /* * Lockdep wants atomic interrupt handlers: */ irqflags |= S