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-rw-r--r--include/linux/clocksource.h14
1 files changed, 10 insertions, 4 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 55e434feec9..f88d32f8ff7 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -45,7 +45,8 @@ struct clocksource;
* @read: returns a cycle value
* @mask: bitmask for two's complement
* subtraction of non 64 bit counters
- * @mult: cycle to nanosecond multiplier
+ * @mult: cycle to nanosecond multiplier (adjusted by NTP)
+ * @mult_orig: cycle to nanosecond multiplier (unadjusted by NTP)
* @shift: cycle to nanosecond divisor (power of two)
* @flags: flags describing special properties
* @vread: vsyscall based read
@@ -63,6 +64,7 @@ struct clocksource {
cycle_t (*read)(void);
cycle_t mask;
u32 mult;
+ u32 mult_orig;
u32 shift;
unsigned long flags;
cycle_t (*vread)(void);
@@ -77,6 +79,7 @@ struct clocksource {
/* timekeeping specific data, ignore */
cycle_t cycle_interval;
u64 xtime_interval;
+ u32 raw_interval;
/*
* Second part is written at each timer interrupt
* Keep it in a different cache line to dirty no
@@ -85,6 +88,7 @@ struct clocksource {
cycle_t cycle_last ____cacheline_aligned_in_smp;
u64 xtime_nsec;
s64 error;
+ struct timespec raw_time;
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
/* Watchdog related data, used by the framework */
@@ -201,17 +205,19 @@ static inline void clocksource_calculate_interval(struct clocksource *c,
{
u64 tmp;
- /* XXX - All of this could use a whole lot of optimization */
+ /* Do the ns -> cycle conversion first, using original mult */
tmp = length_nsec;
tmp <<= c->shift;
- tmp += c->mult/2;
- do_div(tmp, c->mult);
+ tmp += c->mult_orig/2;
+ do_div(tmp, c->mult_orig);
c->cycle_interval = (cycle_t)tmp;
if (c->cycle_interval == 0)
c->cycle_interval = 1;
+ /* Go back from cycles -> shifted ns, this time use ntp adjused mult */
c->xtime_interval = (u64)c->cycle_interval * c->mult;
+ c->raw_interval = ((u64)c->cycle_interval * c->mult_orig) >> c->shift;
}