diff options
| -rw-r--r-- | include/linux/timecounter.h | 31 | ||||
| -rw-r--r-- | kernel/time/timecounter.c | 35 |
2 files changed, 29 insertions, 37 deletions
diff --git a/include/linux/timecounter.h b/include/linux/timecounter.h index dce03a5cafb7..7de6b350e559 100644 --- a/include/linux/timecounter.h +++ b/include/linux/timecounter.h @@ -115,6 +115,15 @@ extern void timecounter_init(struct timecounter *tc, */ extern u64 timecounter_read(struct timecounter *tc); +/* + * This is like cyclecounter_cyc2ns(), but it is used for computing a + * time previous to the time stored in the cycle counter. + */ +static inline u64 cc_cyc2ns_backwards(const struct cyclecounter *cc, u64 cycles, u64 frac) +{ + return ((cycles * cc->mult) - frac) >> cc->shift; +} + /** * timecounter_cyc2time - convert a cycle counter to same * time base as values returned by @@ -131,7 +140,25 @@ extern u64 timecounter_read(struct timecounter *tc); * * Returns: cycle counter converted to nanoseconds since the initial time stamp */ -extern u64 timecounter_cyc2time(const struct timecounter *tc, - u64 cycle_tstamp); +static inline u64 timecounter_cyc2time(const struct timecounter *tc, u64 cycle_tstamp) +{ + const struct cyclecounter *cc = tc->cc; + u64 delta = (cycle_tstamp - tc->cycle_last) & cc->mask; + u64 nsec = tc->nsec, frac = tc->frac; + + /* + * Instead of always treating cycle_tstamp as more recent than + * tc->cycle_last, detect when it is too far in the future and + * treat it as old time stamp instead. + */ + if (unlikely(delta > cc->mask / 2)) { + delta = (tc->cycle_last - cycle_tstamp) & cc->mask; + nsec -= cc_cyc2ns_backwards(cc, delta, frac); + } else { + nsec += cyclecounter_cyc2ns(cc, delta, tc->mask, &frac); + } + + return nsec; +} #endif diff --git a/kernel/time/timecounter.c b/kernel/time/timecounter.c index 3d2a354cfe1c..2e64dbb6302d 100644 --- a/kernel/time/timecounter.c +++ b/kernel/time/timecounter.c @@ -62,38 +62,3 @@ u64 timecounter_read(struct timecounter *tc) } EXPORT_SYMBOL_GPL(timecounter_read); -/* - * This is like cyclecounter_cyc2ns(), but it is used for computing a - * time previous to the time stored in the cycle counter. - */ -static u64 cc_cyc2ns_backwards(const struct cyclecounter *cc, - u64 cycles, u64 mask, u64 frac) -{ - u64 ns = (u64) cycles; - - ns = ((ns * cc->mult) - frac) >> cc->shift; - - return ns; -} - -u64 timecounter_cyc2time(const struct timecounter *tc, - u64 cycle_tstamp) -{ - u64 delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; - u64 nsec = tc->nsec, frac = tc->frac; - - /* - * Instead of always treating cycle_tstamp as more recent - * than tc->cycle_last, detect when it is too far in the - * future and treat it as old time stamp instead. - */ - if (delta > tc->cc->mask / 2) { - delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask; - nsec -= cc_cyc2ns_backwards(tc->cc, delta, tc->mask, frac); - } else { - nsec += cyclecounter_cyc2ns(tc->cc, delta, tc->mask, &frac); - } - - return nsec; -} -EXPORT_SYMBOL_GPL(timecounter_cyc2time); |
