|Last Reviewed: 10/05/2007
| WDT Watchdog Timer Interfaces For The Linux Operating System
| Alan Cox <firstname.lastname@example.org>
| ICS WDT501-P
| ICS WDT501-P (no fan tachometer)
| ICS WDT500-P
|All the interfaces provide /dev/watchdog, which when open must be written
|to within a timeout or the machine will reboot. Each write delays the reboot
|time another timeout. In the case of the software watchdog the ability to
|reboot will depend on the state of the machines and interrupts. The hardware
|boards physically pull the machine down off their own onboard timers and
|will reboot from almost anything.
|A second temperature monitoring interface is available on the WDT501P cards.
|This provides /dev/temperature. This is the machine internal temperature in
|degrees Fahrenheit. Each read returns a single byte giving the temperature.
|The third interface logs kernel messages on additional alert events.
|The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to
|pass IO address and IRQ boot parameters. E.g.:
| wdt.io=0x240 wdt.irq=11
|Other "wdt" driver parameters are:
| heartbeat Watchdog heartbeat in seconds (default 60)
| nowayout Watchdog cannot be stopped once started (kernel
| build parameter)
| tachometer WDT501-P Fan Tachometer support (0=disable, default=0)
| type WDT501-P Card type (500 or 501, default=500)
| WDT501P WDT500P
|Reboot Timer X X
|External Reboot X X
|I/O Port Monitor o o
|Temperature X o
|Fan Speed X o
|Power Under X o
|Power Over X o
|Overheat X o
|The external event interfaces on the WDT boards are not currently supported.
|Minor numbers are however allocated for it.
|Example Watchdog Driver: see samples/watchdog/watchdog-simple.c