Re: [RFC PATCH v1 08/20] kernel: time: Add system time to system counter translation

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Tue, Aug 24, 2021 at 6:48 PM <lakshmi.sowjanya.d@xxxxxxxxx> wrote:

> From: Christopher Hall <christopher.s.hall@xxxxxxxxx>
>
> The GPIOlib event generation interface supplies a time in terms of the
> realtime system clock. The driver must translate the system clock to
> something meaningful to the hardware.
>
> The Intel(R) PMC Timed I/O hardware uses ART to trigger events. For
> most Intel(R) platforms that use TSC for timekeeping this added
> function translates from system clock to TSC. The relation between TSC
> and ART is easily derived from CPUID[15H].
>
> Signed-off-by: Christopher Hall <christopher.s.hall@xxxxxxxxx>
> Signed-off-by: Tamal Saha <tamal.saha@xxxxxxxxx>
> Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@xxxxxxxxx>
> Reviewed-by: Mark Gross <mgross@xxxxxxxxxxxxxxx>

I don't quite understand what this patch does, but it looks very generic.
I think the exact usecase needs to be in the commit message.

In either case, this is a patch TGLX et al needs to look at, we can't
merge timekeeping code without their consent.

Yours,
Linus Walleij