Re: [patch] x86: unify/rewrite SMP TSC sync code

[Wink Saville]

Arjan van de Ven wrote:
> > Actually, we need to ask the CPU/System makers to provide a system wide
> > timer that is independent of the given CPU. I would expect it quite simple
>
> they exist. They're called pmtimer and hpet.
> pmtimer is port io. hpet is memory mapped io.

Thanks for the info. I took a look at Documentation/hpet.txt and drivers/char/hpet.c
and see that hpet_mmap is implemented in the driver but nothing hpet.txt indicates
what is being mapped.

Could you point me to any other documentation? I did find the following:

http://www.intel.com/hardwaredesign/hpetspec_1.pdf

Are you aware of any example user code that uses the mmap capability of hpet?

Thanks,

Wink
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