[U-Boot-Users] CONFIG_HW_WATCHDOG in 1.1.6

Wolfgang Denk
2007-03-20T12:10:24Z

In message <45FFA1BC.2040809@gmx.net> you wrote:
>
> What's the preferred policy to trigger the watchdog in U-Boot? Trigger
> using a timer interrupt (as in lib_ppc/interrupts.c) or add calls to
> WATCHDOG_RESET() to every function which may take longer than some
> fraction of the minimal watchdog period (which is?)?

The minimal watchdog period we've seen in real systems so far is 80
milliseconds, including some tolerance of +/- 20%, so we need to keep
it < 50 millisec.

Normally, we trigger the WD in the timer tick (i. e. every milli-
second); additionally, we have a WD trigger in udelay(), so any
(possibly long) delays based on this are automatically safe.

This should reduce the number of places where a manual WATCHDOG_RESET
is needed to very few.

> I know there are functions which disable interrupts and thus have to
> trigger the watchdog themself (like do_bootm).

I think most of these places are already safe.

Best regards,

Wolfgang Denk

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