Messages in this thread Patch in this message | | | From | Stefan Roese <> | Subject | Re: Bootup support for watchdog with short timeout (touch_nmi_watchdog()?) | Date | Tue, 30 Oct 2007 12:16:14 +0100 |
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[added linuxppc-dev since it's PPC relevant too]
On Tuesday 30 October 2007, Josh Boyer wrote: > On Mon, 29 Oct 2007 15:45:03 -0400 > > lsorense@csclub.uwaterloo.ca (Lennart Sorensen) wrote: > > On Mon, Oct 29, 2007 at 03:22:27PM +0100, Stefan Roese wrote: > > > I'm trying to implement support for a board specific watchdog on a > > > PPC440EPx board with a very short timeout. In this case, the watchdog > > > has to be "kicked" at least every 100ms, even while booting and the > > > real watchdog driver not running yet. While looking for trigger places > > > in the kernel source, I noticed the already existing > > > "touch_nmi_watchdog()" function, which seems to be doing what I need. > > > Even if the name not exactly matches my hardware setup. > > > > > > My question now is, is it recommended to use this > > > touch_nmi_watchdog() "infrastructure" for my PPC custom specific > > > watchdog during bootup? And if yes, should it perhaps be renamed to a > > > more generic name, like "touch_watchdog"? > > > > > > Please advise. Thanks. > > > > No idea really. Who would design a watchdog with such a short trigger > > time? That doesn't seem to be useful in any way.
It definitely is useful in our case, since its a requirement for this "critical" project. It's not needed to have such a short trigger time while booting, but unfortunately this external watchdog only supports one fixed timeout.
> To some degree, it's configurable.
No, I'm afraid it's not configurable in this case.
> But the generic question still > stands. It seems like a decent idea to me. Making touch_watchdog (or > whatever it winds up being called) nice across arches might be fun.
I already have it running on my system using a quick hack (see patch below) in include/asm-ppc/nmi.h (yes, still arch/ppc for now :-( ). But for a clean implementation, that has chances for upstream merge (in arch/powerpc later), I would really like to hear if I should move on further this way.
My impression is, that changing the name from touch_nmi_watchdog() to something like touch_watchdog(), and therefore touching lots of files, makes it more unlikely that this resulting patch will get accepted. But implementing this bootup watchdog support in asm-ppc(asm-powerpc)/nmi.h header seems also not totally correct, since it's not really an NMI in this case.
Any thoughts on this?
Thanks.
Best regards, Stefan
diff --git a/include/asm-ppc/nmi.h b/include/asm-ppc/nmi.h new file mode 100644 index 0000000..f18862b --- /dev/null +++ b/include/asm-ppc/nmi.h @@ -0,0 +1,16 @@ +/* + * linux/include/asm-ppc/nmi.h + */ +#ifndef ASM_NMI_H +#define ASM_NMI_H + +#ifdef BOARD_WATCHDOG_FUNC +#define touch_nmi_watchdog BOARD_WATCHDOG_FUNC +#else +static inline void touch_nmi_watchdog(void) +{ + touch_softlockup_watchdog(); +} +#endif + +#endif /* ASM_NMI_H */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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