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    Subject[PATCHv6 13/16] pps: capture MONOTONIC_RAW timestamps as well
    Date
    MONOTONIC_RAW clock timestamps are ideally suited for frequency
    calculation and also fit well into the original NTP hardpps design. Now
    phase and frequency can be adjusted separately: the former based on
    REALTIME clock and the latter based on MONOTONIC_RAW clock.
    A new function getnstime_raw_and_real is added to timekeeping subsystem
    to capture both timestamps at the same time and atomically.

    Acked-by: John Stultz <johnstul@us.ibm.com>
    Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
    ---
    include/linux/pps_kernel.h | 3 ++-
    include/linux/time.h | 2 ++
    kernel/time/timekeeping.c | 39 +++++++++++++++++++++++++++++++++++++++
    3 files changed, 43 insertions(+), 1 deletions(-)

    diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
    index 1aedf50..6ae8898 100644
    --- a/include/linux/pps_kernel.h
    +++ b/include/linux/pps_kernel.h
    @@ -47,6 +47,7 @@ struct pps_source_info {
    };

    struct pps_event_time {
    + struct timespec ts_raw;
    struct timespec ts_real;
    };

    @@ -99,7 +100,7 @@ static inline void timespec_to_pps_ktime(struct pps_ktime *kt,

    static inline void pps_get_ts(struct pps_event_time *ts)
    {
    - getnstimeofday(&ts->ts_real);
    + getnstime_raw_and_real(&ts->ts_raw, &ts->ts_real);
    }

    #endif /* LINUX_PPS_KERNEL_H */
    diff --git a/include/linux/time.h b/include/linux/time.h
    index 9f15ac7..1e6d3b5 100644
    --- a/include/linux/time.h
    +++ b/include/linux/time.h
    @@ -158,6 +158,8 @@ extern unsigned int alarm_setitimer(unsigned int seconds);
    extern int do_getitimer(int which, struct itimerval *value);
    extern void getnstimeofday(struct timespec *tv);
    extern void getrawmonotonic(struct timespec *ts);
    +extern void getnstime_raw_and_real(struct timespec *ts_raw,
    + struct timespec *ts_real);
    extern void getboottime(struct timespec *ts);
    extern void monotonic_to_bootbased(struct timespec *ts);

    diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
    index 49010d8..f42af9d 100644
    --- a/kernel/time/timekeeping.c
    +++ b/kernel/time/timekeeping.c
    @@ -285,6 +285,45 @@ void ktime_get_ts(struct timespec *ts)
    EXPORT_SYMBOL_GPL(ktime_get_ts);

    /**
    + * getnstime_raw_and_real - get day and raw monotonic time in timespec format
    + * @ts_raw: pointer to the timespec to be set to raw monotonic time
    + * @ts_real: pointer to the timespec to be set to the time of day
    + *
    + * This function reads both the time of day and raw monotonic time at the
    + * same time atomically and stores the resulting timestamps in timespec
    + * format.
    + */
    +void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
    +{
    + unsigned long seq;
    + s64 nsecs_raw, nsecs_real;
    +
    + WARN_ON_ONCE(timekeeping_suspended);
    +
    + do {
    + u32 arch_offset;
    +
    + seq = read_seqbegin(&xtime_lock);
    +
    + *ts_raw = raw_time;
    + *ts_real = xtime;
    +
    + nsecs_raw = timekeeping_get_ns_raw();
    + nsecs_real = timekeeping_get_ns();
    +
    + /* If arch requires, add in gettimeoffset() */
    + arch_offset = arch_gettimeoffset();
    + nsecs_raw += arch_offset;
    + nsecs_real += arch_offset;
    +
    + } while (read_seqretry(&xtime_lock, seq));
    +
    + timespec_add_ns(ts_raw, nsecs_raw);
    + timespec_add_ns(ts_real, nsecs_real);
    +}
    +EXPORT_SYMBOL(getnstime_raw_and_real);
    +
    +/**
    * do_gettimeofday - Returns the time of day in a timeval
    * @tv: pointer to the timeval to be set
    *
    --
    1.7.2.3


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