由于LINUX下應(yīng)用層不能直接訪問寄存器，只要通過驅(qū)動(dòng)程序作為橋梁
// 驅(qū)動(dòng)程序：
#ifndef __KERNEL__
#define __KERNEL__
#endif
#ifdef MODULE
#define __MODULE__
#endif
#include
#include
#include
#include
#include
#include
#include
#include ccess.h>
#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); //計(jì)數(shù)器重載值
r_WTCNT=(unsigned long)ioremap(0x53000008,4); //計(jì)數(shù)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 使能看門狗定時(shí)器
//Division_factor =128(Clock Select=128)
//Interrupt Generation =0(不產(chǎn)生中斷)
//Reset =1(開啟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("");
MODULE_DESCRIPTION("watchdog driver for sc2410");
//應(yīng)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");
}
}