TS-4710 Watchdog

The watchdog is manipulated via the tshwctl utility. The startup scripts automatically run and daemonize tshwctl to feed the watchdog by default. It can be armed in 3 modes (0 - .4s, 1- 2.7s, 2 - 10.8s). It can be either auto-fed from a background process that continually feeds the watchdog while running (--autofeed option), or via a /dev/watchdog UNIX named pipe which receives single ASCII characters which are written to feed it from another application.

Value	Result
0	feed watchdog for another .338s
1	feed watchdog for another 2.706s
2	feed watchdog for another 10.824s
3	disable watchdog

Watchdog by default comes out of reset armed for .338 seconds. TS-BOOTROM firmware feeds for 10.824 and OS code has 10.824 seconds to take over.

You can feed the watchdog from your application by poking a register:

#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>
#include <sys/mman.h>

int main()
{
        int mem;
        volatile uint16_t *syscon;

        mem = open("/dev/mem", O_RDWR|O_SYNC);
        syscon = mmap(0,
                      getpagesize(),
                      PROT_READ|PROT_WRITE,
                      MAP_SHARED,
                      mem,
                      0x80004000);

        for(;;) {
                // This feeds the watchdog for 10s.
                syscon[0x6/2] = 2;
                sleep(5);
        }

        return 0;
}