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    SubjectRe: [RFC PATCH v2 0/4] Add support for S3 non-stop TSC support.
    On Tue, Mar 05, 2013 at 11:53:02AM +0800, Feng Tang wrote:

    > > // Drops some small precision along the way but is simple..
    > > static inline u64 cyclecounter_cyc2ns_128(const struct cyclecounter *cc,
    > > cycle_t cycles)
    > > {
    > > u64 max = U64_MAX/cc->mult;
    > > u64 num = cycles/max;
    > > u64 result = num * ((max * cc->mult) >> cc->shift);
    > > return result + cyclecounter_cyc2ns(cc, cycles - num*cc->mult);
    > > }
    >
    > Your way is surely more accurate, if maintainers are ok with adding
    > the new API, I will use it.

    Okay, give it a good look though, I only wrote it out in email, never
    tested it :)

    > > You may want to also CC the maintainers of all the ARM subsystems that
    > > use read_persistent_clock and check with them to ensure this new
    > > interface will let them migrate their implementations as well.
    >
    > Maybe I didn't get it well, my patches didn't change the
    > read_persistent_clock(), but inject a new way of counting suspended
    > time. It should have no functional changes to existing platforms.

    Right, your patches are fine stand alone.

    The ARM case of plat-omap/counter_32k.c would ideally be converted to
    use your new API though, that is what I ment about involving them.

    I'm not sure about mach-tegra/timer.c though - it seems to be using a
    counter as well but somehow sharing registers with the RTC?

    Regards,
    Jason


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