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 <module.h>
#include <linux/fs.h>
#include <linux/iobuf.h>
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <asm/irq.h>
#include <asm/arch/irqs.h>
#include <asm/semaphore.h>
#include <linux/major.h>
#include <linux/vmalloc.h> #include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
//#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@>");
MODULE_DESCRIPTION("watchdog driver for sc2410");
//应用程序： #include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h> 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");
}
}
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