linux下的ARM看门狗程序

由于LINUX下应用层不能直接访问寄存器，只要通过驱动程序作为桥梁 
 //  驱动程序：
 #ifndef __KERNEL__
 #define __KERNEL__
#endif
#ifdef MODULE
 #define __MODULE__
#endif
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include  
#include
#include
#include
#include
#include
//#define rWTCON   (*(volatile unsigned *)0x53000000)
//#define rWTDAT   (*(volatile unsigned *)0x53000004)
//#define rWTCNT   (*(volatile unsigned *)0x53000008)
#define WATCHDOG_MAJOR 213
#define DEVICE_NAME  "watchdog"
 
static unsigned int r_WTCON,r_WTDAT,r_WTCNT;
devfs_handle_t devfs_wt;
int wt_open(struct inode *,struct file *);
ssize_t wt_write(struct file *,const char *,size_t,loff_t *);
 
static struct file_operations wt_fops={
    owner:    THIS_MODULE,
    open:      wt_open,
 write:     wt_write,
};
 
static int address_map(void)
{
 r_WTCON=(unsigned long)ioremap(0x53000000,4);  //控制寄存器
 r_WTDAT=(unsigned long)ioremap(0x53000004,4);  //计数器重载值
    r_WTCNT=(unsigned long)ioremap(0x53000008,4);  //计数器
    return 0;
}
int __init wt_init(void)
{  
    address_map(); 
    devfs_wt=devfs_register(NULL,DEVICE_NAME,DEVFS_FL_DEFAULT,WATCHDOG_MAJOR, 0, S_IFCHR |S_IRUSR |S_IWUSR |S_IRGRP |S_IWGRP, &wt_fops, NULL);
    return 0;
}
int wt_open(struct inode * inode,struct file * filp)
{
    *(unsigned long *)r_WTCNT=1525 *2;  //2秒
    *(unsigned long *)r_WTCON=0xff39;
    //PCLK=50M
    //Prescaler Value               =255
    // Enable Watchdog              =1  使能看门狗定时器
    //Division_factor                =128(Clock Select=128)
    //Interrupt Generation       =0(不产生中断)
    //Reset                            =1(开启Reset Signal)
    return 0;
}
ssize_t wt_write(struct file *filp,const char * buf ,size_t size,loff_t *offp)
{   
    *(unsigned long *)r_WTCNT=1525 *2;  //2秒
    return 0;
}
void __exit wt_exit(void)
{
   iounmap((void *)r_WTCON);
   iounmap((void *)r_WTDAT);
   iounmap((void *)r_WTCNT);
   devfs_unregister(devfs_wt);
}
module_init(wt_init);
module_exit(wt_exit);
MODULE_LICENSE("watchdog");
MODULE_AUTHOR("<email@mail.com>");
MODULE_DESCRIPTION("watchdog driver for sc2410");
//应用程序：
#include
#include
#include
#include
#include
int main(void)
{
    int wt_fd; 
    wt_fd = open("/dev/watchdog", O_RDWR);
 if(wt_fd<=0)
 {
        printf("open watchdog  device is wrong!\n");
  return 0;
 }
    while (1) {
        sleep(1);
        write(wt_fd,NULL,0);
        printf("feed watchdog!\n");
    }
}