Watchdog

On this page, you will find usefull informations to configure and use the Watchdog of your APF boards.

Configuration

First be sure to have the Watchdog Linux driver activated:

 $ make linux26-menuconfig

[*] Watchdog Timer Support  --->
    <M>   IMX2+  Watchdog

 $ make

Installation

If you choose to include driver in Linux kernel then reflash your kernel image.
Else either copy the generated module through NFS to your board or reflash your rootfs.

Usage

• Load the module (here with a 5 secs timeout):

 # modprobe imx2-wdt timeout=5

Note: On APF51 the watchdog driver is compiled within the kernel and do not need to be loaded at runtime.

You can now access the watchdog through /dev/watchdog device file:

• to activate it, just open the file, then you will have to write to this file regularly or your system will be reseted.

Note: On APF27 and APF51 the watchdog is then unstoppable and will reset your board if you don't service it

• there is a small daemon useful to periodically trig the watchdog and reset or reboot the apf board on timeout (here reset watchdog every 3 seconds and ask to reboot after 5s if not serviced):

 # watchdog -T 5 -t 3 /dev/watchdog

If your system hangs, the daemon can't trig the watchdog and your system is reseted. To quickly check that you can do a:

 # killall watchdog