diff options
| -rw-r--r-- | arch/arm/plat-omap/common.c | 7 | ||||
| -rw-r--r-- | include/linux/clocksource.h | 4 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 53 |
3 files changed, 27 insertions, 37 deletions
diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c index ebcf006406f9..95587b6c0259 100644 --- a/arch/arm/plat-omap/common.c +++ b/arch/arm/plat-omap/common.c @@ -253,11 +253,8 @@ static struct clocksource clocksource_32k = { */ unsigned long long sched_clock(void) { - unsigned long long ret; - - ret = (unsigned long long)clocksource_32k.read(&clocksource_32k); - ret = (ret * clocksource_32k.mult_orig) >> clocksource_32k.shift; - return ret; + return clocksource_cyc2ns(clocksource_32k.read(&clocksource_32k), + clocksource_32k.mult, clocksource_32k.shift); } static int __init omap_init_clocksource_32k(void) diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index e12e3095e2fb..e34015effeb6 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -149,8 +149,7 @@ extern u64 timecounter_cyc2time(struct timecounter *tc, * @disable: optional function to disable the clocksource * @mask: bitmask for two's complement * subtraction of non 64 bit counters - * @mult: cycle to nanosecond multiplier (adjusted by NTP) - * @mult_orig: cycle to nanosecond multiplier (unadjusted by NTP) + * @mult: cycle to nanosecond multiplier * @shift: cycle to nanosecond divisor (power of two) * @flags: flags describing special properties * @vread: vsyscall based read @@ -168,7 +167,6 @@ struct clocksource { void (*disable)(struct clocksource *cs); cycle_t mask; u32 mult; - u32 mult_orig; u32 shift; unsigned long flags; cycle_t (*vread)(void); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index dfdab1cefe1e..f4056f6c2632 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -41,6 +41,8 @@ struct timekeeper { /* Shift conversion between clock shifted nano seconds and * ntp shifted nano seconds. */ int ntp_error_shift; + /* NTP adjusted clock multiplier */ + u32 mult; }; struct timekeeper timekeeper; @@ -66,8 +68,8 @@ static void timekeeper_setup_internals(struct clocksource *clock) /* Do the ns -> cycle conversion first, using original mult */ tmp = NTP_INTERVAL_LENGTH; tmp <<= clock->shift; - tmp += clock->mult_orig/2; - do_div(tmp, clock->mult_orig); + tmp += clock->mult/2; + do_div(tmp, clock->mult); if (tmp == 0) tmp = 1; @@ -77,13 +79,20 @@ static void timekeeper_setup_internals(struct clocksource *clock) /* Go back from cycles -> shifted ns */ timekeeper.xtime_interval = (u64) interval * clock->mult; timekeeper.raw_interval = - ((u64) interval * clock->mult_orig) >> clock->shift; + ((u64) interval * clock->mult) >> clock->shift; timekeeper.xtime_nsec = 0; timekeeper.shift = clock->shift; timekeeper.ntp_error = 0; timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; + + /* + * The timekeeper keeps its own mult values for the currently + * active clocksource. These value will be adjusted via NTP + * to counteract clock drifting. + */ + timekeeper.mult = clock->mult; } /* @@ -154,14 +163,15 @@ static void timekeeping_forward_now(void) cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; clock->cycle_last = cycle_now; - nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); + nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, + timekeeper.shift); /* If arch requires, add in gettimeoffset() */ nsec += arch_gettimeoffset(); timespec_add_ns(&xtime, nsec); - nsec = clocksource_cyc2ns(cycle_delta, clock->mult_orig, clock->shift); + nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); timespec_add_ns(&raw_time, nsec); } @@ -193,8 +203,8 @@ void getnstimeofday(struct timespec *ts) cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; /* convert to nanoseconds: */ - nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, - clock->shift); + nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, + timekeeper.shift); /* If arch requires, add in gettimeoffset() */ nsecs += arch_gettimeoffset(); @@ -228,8 +238,8 @@ ktime_t ktime_get(void) cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; /* convert to nanoseconds: */ - nsecs += clocksource_cyc2ns(cycle_delta, clock->mult, - clock->shift); + nsecs += clocksource_cyc2ns(cycle_delta, timekeeper.mult, + timekeeper.shift); } while (read_seqretry(&xtime_lock, seq)); /* @@ -271,8 +281,8 @@ void ktime_get_ts(struct timespec *ts) cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; /* convert to nanoseconds: */ - nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, - clock->shift); + nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, + timekeeper.shift); } while (read_seqretry(&xtime_lock, seq)); @@ -356,22 +366,10 @@ static void change_clocksource(void) if (new->enable && !new->enable(new)) return; - /* - * The frequency may have changed while the clocksource - * was disabled. If so the code in ->enable() must update - * the mult value to reflect the new frequency. Make sure - * mult_orig follows this change. - */ - new->mult_orig = new->mult; old = timekeeper.clock; timekeeper_setup_internals(new); - /* - * Save mult_orig in mult so that the value can be restored - * regardless if ->enable() updates the value of mult or not. - */ - old->mult = old->mult_orig; if (old->disable) old->disable(old); @@ -461,7 +459,7 @@ void getrawmonotonic(struct timespec *ts) cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; /* convert to nanoseconds: */ - nsecs = clocksource_cyc2ns(cycle_delta, clock->mult_orig, + nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); *ts = raw_time; @@ -521,9 +519,6 @@ void __init timekeeping_init(void) clock = clocksource_default_clock(); if (clock->enable) clock->enable(clock); - /* set mult_orig on enable */ - clock->mult_orig = clock->mult; - timekeeper_setup_internals(clock); xtime.tv_sec = sec; @@ -697,7 +692,7 @@ static void timekeeping_adjust(s64 offset) } else return; - timekeeper.clock->mult += adj; + timekeeper.mult += adj; timekeeper.xtime_interval += interval; timekeeper.xtime_nsec -= offset; timekeeper.ntp_error -= (interval - offset) << @@ -789,7 +784,7 @@ void update_wall_time(void) timekeeper.ntp_error += timekeeper.xtime_nsec << timekeeper.ntp_error_shift; - nsecs = clocksource_cyc2ns(offset, clock->mult, clock->shift); + nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); update_xtime_cache(nsecs); /* check to see if there is a new clocksource to use */ |