内核选中红框部分，确保有/dev/watchdog

include <errno.h>

include <fcntl.h>

include <stdlib.h>

include <string.h>

include <unistd.h>

include "stdio.h"

include <unistd.h> / System V /

include <sys/ioctl.h> / BSD and Linux /

include <stropts.h> / XSI STREAMS /

include <linux/watchdog.h>

define DEV_NAME "/dev/watchdog"

int fd;

/*

• @brief 初始化看门狗
• @param interval 喂狗时间
• @param margin 喂狗间隔保留时间
• @return int
• @create at 2019.09.04 by Eric.Xi

*/
int watch_dog_init(int interval,int margin)
{

 printf("started (interval %d, margin %d)!\n", interval, margin);

fd = open(DEV_NAME, O_RDWR|O_CLOEXEC);
if (fd == -1) {
    printf("Failed to open %s: %s\n", DEV_NAME, strerror(errno));
    return 1;
}

int timeout = interval + margin;
int ret = ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
if (ret) {
    printf("Failed to set timeout to %d: %s\n", timeout, strerror(errno));
    ret = ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
    if (ret) {
        printf("Failed to get timeout: %s\n", strerror(errno));
    } else {
        if (timeout > margin) {
            interval = timeout - margin;
        } else {
            interval = 1;
        }
        printf("Adjusted interval to timeout returned by driver:"
                " timeout %d, interval %d, margin %d\n",
                timeout, interval, margin);
    }
}
return 0;

}

/*

• @brief 喂看门狗
• @param interval 喂狗时间
• @param fd 看门狗句柄
• @return int
• @create at 2019.09.04 by Eric.Xi

*/
int watch_dog_feed(int fd, int interval)
{

write(fd, "", 1);
sleep(interval);
return 0;

}

/*

• @brief 看门狗使用ｄｅｍｏ
• @return int
• @create at 2019.09.04 by Eric.Xi

*/
int main(int argc, char **argv)
{

int interval = 1;
int margin =2;
int ret;
ret = watch_dog_init(interval,margin);
if(ret<0){
    return -1;
}


    while (true) {
        watch_dog_feed(fd ,interval);
     printf("------feed--------\n");
    
    }

}