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authorAlexander Gordeev <lasaine@lvk.cs.msu.su>2011-01-12 17:00:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 08:03:21 -0800
commite2c18e49a0d4f822ffc29fb4958943beb1ff08b7 (patch)
tree227dbb544277f7908fa1666ce21a15e6b2282ccb /kernel
parent025b40abe715d638e60516a657d354e8560c1a85 (diff)
downloadlinux-linaro-precise-e2c18e49a0d4f822ffc29fb4958943beb1ff08b7.tar.gz
pps: capture MONOTONIC_RAW timestamps as well
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> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/timekeeping.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5bb86da8200..5536aaf3ba3 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -288,6 +288,49 @@ void ktime_get_ts(struct timespec *ts)
}
EXPORT_SYMBOL_GPL(ktime_get_ts);
+#ifdef CONFIG_NTP_PPS
+
+/**
+ * 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);
+
+#endif /* CONFIG_NTP_PPS */
+
/**
* do_gettimeofday - Returns the time of day in a timeval
* @tv: pointer to the timeval to be set