This driver supports some arm and arm64 boards equipped with "snps,dw-wdt"-compatible watchdog device. Tested on RK3399-based board (RockPro64). Once started watchdog device cannot be stopped. Interrupt handler has mode to kick watchdog even when software does not do it properly. This can be controlled via sysctl: dev.dwwdt.prevent_restart. Also - driver handles system shutdown and prevents from restart when system is asked to reboot.
- RK3399 TRM Part 1 (it lacks details on clock configuration)
- OpenBSD driver (it uses watchdog device to reset system): https://github.com/openbsd/src/blob/master/sys/dev/fdt/dwdog.c
- Linux driver (there is no 1:1 compatibility right now, but Linux folks have the same problem with clock configuration): https://github.com/torvalds/linux/blob/master/drivers/watchdog/dw_wdt.c