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authorjohn stultz <johnstul@us.ibm.com>2009-05-01 13:10:26 -0700
committerThomas Gleixner <tglx@linutronix.de>2009-05-02 11:45:15 +0200
commit7d27558c4138ac6b3684dea35c2f4379b940a7dd (patch)
treec10f5cee4dda1e6bc7977d016db020377f97feab /kernel/time
parenta25cbd045a2ffc42787d4dbcbb9c7118f5f42732 (diff)
downloadlinux-7d27558c4138ac6b3684dea35c2f4379b940a7dd.tar.bz2
timekeeping: create arch_gettimeoffset infrastructure
Some arches don't supply their own clocksource. This is mainly the case in architectures that get their inter-tick times by reading the counter on their interval timer. Since these timers wrap every tick, they're not really useful as clocksources. Wrapping them to act like one is possible but not very efficient. So we provide a callout these arches can implement for use with the jiffies clocksource to provide finer then tick granular time. [ Impact: ease the migration to generic time keeping ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/timekeeping.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 687dff49f6e7..e97c50f8458b 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -77,6 +77,10 @@ static void clocksource_forward_now(void)
clock->cycle_last = cycle_now;
nsec = cyc2ns(clock, cycle_delta);
+
+ /* If arch requires, add in gettimeoffset() */
+ nsec += arch_gettimeoffset();
+
timespec_add_ns(&xtime, nsec);
nsec = ((s64)cycle_delta * clock->mult_orig) >> clock->shift;
@@ -111,6 +115,9 @@ void getnstimeofday(struct timespec *ts)
/* convert to nanoseconds: */
nsecs = cyc2ns(clock, cycle_delta);
+ /* If arch requires, add in gettimeoffset() */
+ nsecs += arch_gettimeoffset();
+
} while (read_seqretry(&xtime_lock, seq));
timespec_add_ns(ts, nsecs);