From a58c9f3c1e929c3c323c26dbdafef46373a719d4 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 22 Feb 2007 04:16:21 -0800 Subject: [PATCH] [SPARC64]: Synchronize RTC clock via timer just like x86. Signed-off-by: David S. Miller --- arch/sparc64/kernel/time.c | 66 +++++++++++++++++++++++++++----------- 1 file changed, 48 insertions(+), 18 deletions(-) diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c index f84da4f1b7..d457079118 100644 --- a/arch/sparc64/kernel/time.c +++ b/arch/sparc64/kernel/time.c @@ -435,22 +435,56 @@ static unsigned long timer_ticks_per_nsec_quotient __read_mostly; #define TICK_SIZE (tick_nsec / 1000) -static inline void timer_check_rtc(void) +#define USEC_AFTER 500000 +#define USEC_BEFORE 500000 + +static void sync_cmos_clock(unsigned long dummy); + +static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0); + +static void sync_cmos_clock(unsigned long dummy) { - /* last time the cmos clock got updated */ - static long last_rtc_update; - - /* Determine when to update the Mostek clock. */ - if (ntp_synced() && - xtime.tv_sec > last_rtc_update + 660 && - (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && - (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { - if (set_rtc_mmss(xtime.tv_sec) == 0) - last_rtc_update = xtime.tv_sec; - else - last_rtc_update = xtime.tv_sec - 600; - /* do it again in 60 s */ + struct timeval now, next; + int fail = 1; + + /* + * If we have an externally synchronized Linux clock, then update + * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be + * called as close as possible to 500 ms before the new second starts. + * This code is run on a timer. If the clock is set, that timer + * may not expire at the correct time. Thus, we adjust... + */ + if (!ntp_synced()) + /* + * Not synced, exit, do not restart a timer (if one is + * running, let it run out). + */ + return; + + do_gettimeofday(&now); + if (now.tv_usec >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 && + now.tv_usec <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2) + fail = set_rtc_mmss(now.tv_sec); + + next.tv_usec = USEC_AFTER - now.tv_usec; + if (next.tv_usec <= 0) + next.tv_usec += USEC_PER_SEC; + + if (!fail) + next.tv_sec = 659; + else + next.tv_sec = 0; + + if (next.tv_usec >= USEC_PER_SEC) { + next.tv_sec++; + next.tv_usec -= USEC_PER_SEC; } + mod_timer(&sync_cmos_timer, jiffies + timeval_to_jiffies(&next)); +} + +void notify_arch_cmos_timer(void) +{ + mod_timer(&sync_cmos_timer, jiffies + 1); } irqreturn_t timer_interrupt(int irq, void *dev_id) @@ -483,8 +517,6 @@ irqreturn_t timer_interrupt(int irq, void *dev_id) : "r" (pstate)); } while (time_after_eq(ticks, compare)); - timer_check_rtc(); - write_sequnlock(&xtime_lock); return IRQ_HANDLED; @@ -497,8 +529,6 @@ void timer_tick_interrupt(struct pt_regs *regs) do_timer(1); - timer_check_rtc(); - write_sequnlock(&xtime_lock); } #endif -- 2.39.5