Who is refreshing hardware watchdog in Linux?

Question

I have a processor AT91SAM9G20 running a 2.6 kernel. Watchdog is enabled at bootstrap level and configured for 16 seconds. Watchdog mode register can be configured only once

Answer 1

This may give you a hint: http://www.mjmwired.net/kernel/Documentation/watchdog/watchdog-api.txt

It makes perfect sense to have a user space daemon handling the watchdog. It probably defaults to a 15 minute timeout.