watch-dog-test

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hi3521 watch dog

更新記錄

item note
20150916 第一版

目錄

HI3520D WatchDog

載入watch dog ko

  • insmod ./wdt.ko default_margin=5
    • 將產生每5秒hidog_feed

kernel介面如下

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#define HIDOG_EXIT    	0
#define HIDOG_SELFCLR   1
#define HIDOG_EXTCLR    2

volatile static unsigned int hidog_state = 0;

static struct file_operations hidog_fops = {
    .owner        = THIS_MODULE,
    .llseek        = no_llseek,
    .write        = hidog_write,
    .unlocked_ioctl = hidog_ioctl,
    .open        = hidog_open,
    .release    = hidog_release,
};

測試watch dog

  • wdt-test
    • 開啟/dev/watchdog，此時hidog_state會由HIDOG_SELFCLR切為HIDOG_EXTCLR
    • 產生watchdog time out reboot
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#include <stdio.h>
#include <fcntl.h>
int main(void)
{
        int wtd_fd;
        wtd_fd=open("/dev/watchdog",O_RDWR);

        if(wtd_fd<=0)
        {
                printf("type 0:wtd WDIOC_GETSUPPORT\n");
        }
        while(1) sleep(10);
}

watchdog kernel 產生程序

  • 當測試程式有while(1)時
    • 開啟/dev/watchdog產生 kernel/open (即hidog_open)
    • 此時hidog_state由HIDOG_SELFCLR改變為HIDOG_EXTCLR，將不會再產生hidog_feed
    • 等到timeout時間到reboot
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hidog_keepalive entry, hidog_state:1
hidog_open 00 entry, ret:0, hidog_state:1
hidog_open 11 entry, ret:0, hidog_state:2
hidog_deamon entry, hidog_state:2
  • 當測試程式無while(1)時
    • 在關閉/dev/watchdog產生 kernel/release (即hidog_release)
    • 將hidog_state由HIDOG_EXTCLR改變為HIDOG_SELFCLR，將會再次自動產生hidog_feed 
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hidog_keepalive entry, hidog_state:1
hidog_open 00 entry, ret:0, hidog_state:1
hidog_open 11 entry, ret:0, hidog_state:2
hidog_release 00 entry, hidog_state:2,cur_margin:5
hidog_release 11 entry, hidog_state:1
hidog_deamon entry, hidog_state:1

使用echo

  • 當採用echo ‘V’，將nowayout設定為1（即不能rmmod wdt.ko)
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 # echo a > /dev/watchdog 
hidog_keepalive entry, hidog_state:1
hidog_open 00 entry, ret:0, hidog_state:1
hidog_open 11 entry, ret:0, hidog_state:2
hidog_write 00 entry, len:2,hidog_state:2
hidog_keepalive entry, hidog_state:2
hidog_write 11 entry, len:2,hidog_state:2
hidog_release 00 entry, hidog_state:2,cur_margin:5
hidog_release 11 entry, hidog_state:1
hidog_deamon entry, hidog_state:1
# hidog_deamon entry, hidog_state:1

hidog_write程式內容

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static ssize_t hidog_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
{
    /*
     *      *    Refresh the timer.
     *           */

    printk("hidog_write 00 entry, len:%d,hidog_state:%d\n",len,hidog_state);
    if(len) {        
        size_t i;

        nowayout = 0;

        for (i = 0; i != len; i++) {
            char c;

            if (get_user(c, data + i))
                return -EFAULT;
            if (c == 'V')           
                nowayout = 1;
        }
        hidog_keepalive();
    }

    printk("hidog_write 11 entry, len:%d,hidog_state:%d\n",len,hidog_state);
    return len;
}

使用busybox watchdog

  • insmod ./wdt-dd.ko default_margin=5 nodeamon=1
    • 設定載入時不要自帶feed deamon
    • watchdog -t 5 /dev/watchdog
    • 由busybox的watchdog去feed
    • 此時會產生watchdog processs，若將此process刪除將會於60S後產生timeout
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1166 root      3180 S    -sh
1193 root      3044 S    watchdog -t 5 /dev/watchdog
1194 root      3180 S    -sh
1195 root      3180 R    ps
  • busybox watchdog feed會產生write訊息，就會產生hidog_keepalive
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# watchdog -t 5 /dev/watchdog 
hidog_keepalive entry, hidog_state:1
# hidog_open 00 entry, ret:0, hidog_state:1
hidog_open 11 entry, ret:0, hidog_state:2
hidog_ioctl entry, cmd:-2147199228
hidog_ioctl entry, cmd:-1073457402
hidog_keepalive entry, hidog_state:2
hidog_write 00 entry, len:1,hidog_state:2
hidog_keepalive entry, hidog_state:2
hidog_write 11 entry, len:1,hidog_state:2
hidog_write 00 entry, len:1,hidog_state:2
hidog_keepalive entry, hidog_state:2
hidog_write 11 entry, len:1,hidog_state:2
hidog_write 00 entry, len:1,hidog_state:2
hidog_keepalive entry, hidog_state:2
hidog_write 11 entry, len:1,hidog_state:2

# 
# 
# hidog_write 00 entry, len:1,hidog_state:2
hidog_keepalive entry, hidog_state:2
hidog_write 11 entry, len:1,hidog_state:2

busybox 程式如下

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int watchdog_main(int argc, char **argv)
...
	while (1) {
		/*
		 * Make sure we clear the counter before sleeping,
		 * as the counter value is undefined at this point -- PFM
		 */
		write(3, "", 1); /* write zero byte */
		usleep(stimer_duration * 1000L);
	}

watchdog 測試方式

  • 帶起watchdog之後，手動刪除watchdog(killall watchdog)，再5秒後將會產生硬体動啟 
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insmod ./wdt-dd.ko default_margin=5 nodeamon=1
watchdog -t 4 -T 5 /dev/watchdog

其它說明

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BusyBox v1.16.1 (2013-07-17 17:28:26 CST) multi-call binary.

Usage: watchdog [-t N[ms]] [-T N[ms]] [-F] DEV

Periodically write to watchdog device DEV

Options:
        -T N    Reboot after N seconds if not reset (default 60)
        -t N    Reset every N seconds (default 30)
        -F      Run in foreground

Use 500ms to specify period in milliseconds