Linux中断子系统：request_irq()

Posted 2021-09-10 rtoax

https://gitee.com/rtoax/test/tree/master/linux/interrupt/request_irq

#include <linux/module.h>    // included for all kernel modules
#include <linux/kernel.h>    // included for KERN_INFO
#include <linux/init.h>      // included for __init and __exit macros
#include <linux/interrupt.h> // included for request_irq and free_irq macros

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rong Tao");
MODULE_DESCRIPTION("A Simple request irq module");
MODULE_VERSION("0.1");

static char *name = "[RToax]";
module_param( name, charp, S_IRUGO);
MODULE_PARM_DESC(name, "[RToax] irq name");	

/**
 *  找一个 /proc/interrupt 中没有的 中断号
 */
#define IRQ_NUM 2

irqreturn_t no_action(int cpl, void *dev_id)
{
    printk(KERN_INFO "[RToax]cpl %d!\\n", cpl);
	return IRQ_NONE;
}


static int __init rtoax_irq_init(void) {
    
	printk(KERN_INFO "[RToax]request irq %s!\\n", name);
    /*
     *  注册中断
     */
    if (request_irq(IRQ_NUM, no_action, IRQF_NO_THREAD, name, NULL))
	    printk(KERN_ERR "%s: request_irq() failed\\n", name);
	return 0;
}

static void __exit rtoax_irq_cleanup(void) {
	printk(KERN_INFO "[RToax]free irq.\\n");
    /*
     *  释放中断
     */
    free_irq(IRQ_NUM, NULL);
}

module_init(rtoax_irq_init);
module_exit(rtoax_irq_cleanup);

Makefile

obj-m += request-irq.o

all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

测试

[rongtao@localhost request_irq]$ make 
make -C /lib/modules/3.10.0-1062.el7.x86_64/build M=/home/rongtao/test/linux/interrupt/request_irq modules
make[1]: 进入目录“/usr/src/kernels/3.10.0-1062.el7.x86_64”
  CC [M]  /home/rongtao/test/linux/interrupt/request_irq/request-irq.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/rongtao/test/linux/interrupt/request_irq/request-irq.mod.o
  LD [M]  /home/rongtao/test/linux/interrupt/request_irq/request-irq.ko
make[1]: 离开目录“/usr/src/kernels/3.10.0-1062.el7.x86_64”
[rongtao@localhost request_irq]$ sudo insmod request-irq.ko 
[rongtao@localhost request_irq]$ cat /proc/interrupts | grep RToax
   2:          0          0          0          0    XT-PIC-XT-PIC    [RToax]
[rongtao@localhost request_irq]$ sudo rmmod request-irq.ko