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Subject[PATCHv3 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.

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 | 34 ++++++++++++++++++++++++++++++++++
3 files changed, 38 insertions(+), 1 deletions(-)
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 5af0498..39fc712 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -48,6 +48,7 @@ struct pps_source_info {
};

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

@@ -111,7 +112,7 @@ 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 ea3559f..1da8a7b 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -143,6 +143,8 @@ 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 caf8d4d..ef37b14 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -286,6 +286,40 @@ void ktime_get_ts(struct timespec *ts)
EXPORT_SYMBOL_GPL(ktime_get_ts);

/**
+ * getnstime_raw_and_real - Returns both the time of day an raw
+ * monotonic time in a timespec format
+ * @ts_mono_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
+ */
+void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
+{
+ unsigned long seq;
+ s64 nsecs_raw, nsecs_real;
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ 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() */
+ nsecs_real += arch_gettimeoffset();
+
+ } 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
*
--
1.7.1


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