ARM SBSA Generic Watchdog has two stage timeouts:
the first signal (WS0) is for alerting the system by interrupt,
the second one (WS1) is a real hardware reset.
More details: ARM DEN0029B - Server Base System Architecture (SBSA)

This driver can operate ARM SBSA Generic Watchdog as a single stage
or a two stages watchdog, it depends on the module parameter "action".

Note: the maximum timeout in the two stages mode is half of that in
the single stage mode.

To compile this driver as module, choose M here: The module
will be called sbsa_gwdt.