From: John Stultz persistent clock support: do proper timekeeping across suspend/resume. Signed-off-by: John Stultz Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar -- include/linux/hrtimer.h | 3 +++ include/linux/time.h | 1 + kernel/hrtimer.c | 8 ++++++++ kernel/timer.c | 34 +++++++++++++++++++++++++++++++--- 4 files changed, 43 insertions(+), 3 deletions(-) linux-2.6.18-rc6_timeofday-persistent-clock-generic_C6.patch Index: linux-2.6.18-mm2/include/linux/hrtimer.h =================================================================== --- linux-2.6.18-mm2.orig/include/linux/hrtimer.h 2006-09-30 01:41:14.000000000 +0200 +++ linux-2.6.18-mm2/include/linux/hrtimer.h 2006-09-30 01:41:15.000000000 +0200 @@ -146,6 +146,9 @@ extern void hrtimer_init_sleeper(struct /* Soft interrupt function to run the hrtimer queues: */ extern void hrtimer_run_queues(void); +/* Resume notification */ +void hrtimer_notify_resume(void); + /* Bootup initialization: */ extern void __init hrtimers_init(void); Index: linux-2.6.18-mm2/include/linux/time.h =================================================================== --- linux-2.6.18-mm2.orig/include/linux/time.h 2006-09-30 01:41:14.000000000 +0200 +++ linux-2.6.18-mm2/include/linux/time.h 2006-09-30 01:41:15.000000000 +0200 @@ -92,6 +92,7 @@ extern struct timespec xtime; extern struct timespec wall_to_monotonic; extern seqlock_t xtime_lock; +extern unsigned long read_persistent_clock(void); void timekeeping_init(void); static inline unsigned long get_seconds(void) Index: linux-2.6.18-mm2/kernel/hrtimer.c =================================================================== --- linux-2.6.18-mm2.orig/kernel/hrtimer.c 2006-09-30 01:41:14.000000000 +0200 +++ linux-2.6.18-mm2/kernel/hrtimer.c 2006-09-30 01:41:15.000000000 +0200 @@ -287,6 +287,14 @@ static unsigned long ktime_divns(const k #endif /* BITS_PER_LONG >= 64 */ /* + * Timekeeping resumed notification + */ +void hrtimer_notify_resume(void) +{ + clock_was_set(); +} + +/* * Counterpart to lock_timer_base above: */ static inline Index: linux-2.6.18-mm2/kernel/timer.c =================================================================== --- linux-2.6.18-mm2.orig/kernel/timer.c 2006-09-30 01:41:14.000000000 +0200 +++ linux-2.6.18-mm2/kernel/timer.c 2006-09-30 01:41:15.000000000 +0200 @@ -41,6 +41,9 @@ #include #include +/* jiffies at the most recent update of wall time */ +unsigned long wall_jiffies = INITIAL_JIFFIES; + u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; EXPORT_SYMBOL(jiffies_64); @@ -743,12 +746,20 @@ int timekeeping_is_continuous(void) return ret; } +/* Weak dummy function for arches that do not yet support it. + * XXX - Do be sure to remove it once all arches implement it. + */ +unsigned long __attribute__((weak)) read_persistent_clock(void) +{ + return 0; +} + /* * timekeeping_init - Initializes the clocksource and common timekeeping values */ void __init timekeeping_init(void) { - unsigned long flags; + unsigned long flags, sec = read_persistent_clock(); write_seqlock_irqsave(&xtime_lock, flags); @@ -758,11 +769,18 @@ void __init timekeeping_init(void) clocksource_calculate_interval(clock, tick_nsec); clock->cycle_last = clocksource_read(clock); + xtime.tv_sec = sec; + xtime.tv_nsec = (jiffies % HZ) * (NSEC_PER_SEC / HZ); + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + write_sequnlock_irqrestore(&xtime_lock, flags); } static int timekeeping_suspended; +static unsigned long timekeeping_suspend_time; + /** * timekeeping_resume - Resumes the generic timekeeping subsystem. * @dev: unused @@ -773,14 +791,23 @@ static int timekeeping_suspended; */ static int timekeeping_resume(struct sys_device *dev) { - unsigned long flags; + unsigned long flags, now = read_persistent_clock(); write_seqlock_irqsave(&xtime_lock, flags); - /* restart the last cycle value */ + + if (now && (now > timekeeping_suspend_time)) { + unsigned long sleep_length = now - timekeeping_suspend_time; + xtime.tv_sec += sleep_length; + jiffies_64 += sleep_length * HZ; + } + /* re-base the last cycle value */ clock->cycle_last = clocksource_read(clock); clock->error = 0; timekeeping_suspended = 0; write_sequnlock_irqrestore(&xtime_lock, flags); + + hrtimer_notify_resume(); + return 0; } @@ -790,6 +817,7 @@ static int timekeeping_suspend(struct sy write_seqlock_irqsave(&xtime_lock, flags); timekeeping_suspended = 1; + timekeeping_suspend_time = read_persistent_clock(); write_sequnlock_irqrestore(&xtime_lock, flags); return 0; } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/