mirror of https://gitee.com/openkylin/linux.git
235 lines
6.2 KiB
C
235 lines
6.2 KiB
C
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/* time.c: FRV arch-specific time handling
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*
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* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from arch/m68k/kernel/time.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h> /* CONFIG_HEARTBEAT */
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/string.h>
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#include <linux/interrupt.h>
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#include <linux/profile.h>
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#include <linux/irq.h>
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#include <linux/mm.h>
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#include <asm/io.h>
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#include <asm/timer-regs.h>
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#include <asm/mb-regs.h>
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#include <asm/mb86943a.h>
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#include <asm/irq-routing.h>
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#include <linux/timex.h>
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#define TICK_SIZE (tick_nsec / 1000)
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extern unsigned long wall_jiffies;
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u64 jiffies_64 = INITIAL_JIFFIES;
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EXPORT_SYMBOL(jiffies_64);
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unsigned long __nongprelbss __clkin_clock_speed_HZ;
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unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
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unsigned long __nongprelbss __res_bus_clock_speed_HZ;
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unsigned long __nongprelbss __sdram_clock_speed_HZ;
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unsigned long __nongprelbss __core_bus_clock_speed_HZ;
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unsigned long __nongprelbss __core_clock_speed_HZ;
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unsigned long __nongprelbss __dsu_clock_speed_HZ;
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unsigned long __nongprelbss __serial_clock_speed_HZ;
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unsigned long __delay_loops_MHz;
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static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
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static struct irqaction timer_irq = {
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timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE, "timer", NULL, NULL
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};
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static inline int set_rtc_mmss(unsigned long nowtime)
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{
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return -1;
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}
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/*
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* timer_interrupt() needs to keep up the real-time clock,
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* as well as call the "do_timer()" routine every clocktick
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*/
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static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
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{
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/* last time the cmos clock got updated */
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static long last_rtc_update = 0;
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/*
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* Here we are in the timer irq handler. We just have irqs locally
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* disabled but we don't know if the timer_bh is running on the other
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* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
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* the irq version of write_lock because as just said we have irq
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* locally disabled. -arca
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*/
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write_seqlock(&xtime_lock);
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do_timer(regs);
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update_process_times(user_mode(regs));
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profile_tick(CPU_PROFILING, regs);
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/*
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* If we have an externally synchronized Linux clock, then update
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* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
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* called as close as possible to 500 ms before the new second starts.
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*/
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if ((time_status & STA_UNSYNC) == 0 &&
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xtime.tv_sec > last_rtc_update + 660 &&
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(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
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(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
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) {
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if (set_rtc_mmss(xtime.tv_sec) == 0)
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last_rtc_update = xtime.tv_sec;
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else
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last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
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}
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#ifdef CONFIG_HEARTBEAT
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static unsigned short n;
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n++;
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__set_LEDS(n);
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#endif /* CONFIG_HEARTBEAT */
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write_sequnlock(&xtime_lock);
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return IRQ_HANDLED;
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}
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void time_divisor_init(void)
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{
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unsigned short base, pre, prediv;
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/* set the scheduling timer going */
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pre = 1;
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prediv = 4;
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base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
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__set_TPRV(pre);
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__set_TxCKSL_DATA(0, prediv);
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__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
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__set_TCSR_DATA(0, base & 0xff);
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__set_TCSR_DATA(0, base >> 8);
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}
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void time_init(void)
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{
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unsigned int year, mon, day, hour, min, sec;
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extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
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/* FIX by dqg : Set to zero for platforms that don't have tod */
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/* without this time is undefined and can overflow time_t, causing */
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/* very stange errors */
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year = 1980;
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mon = day = 1;
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hour = min = sec = 0;
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arch_gettod (&year, &mon, &day, &hour, &min, &sec);
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if ((year += 1900) < 1970)
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year += 100;
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xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
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xtime.tv_nsec = 0;
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/* install scheduling interrupt handler */
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setup_irq(IRQ_CPU_TIMER0, &timer_irq);
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time_divisor_init();
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}
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/*
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* This version of gettimeofday has near microsecond resolution.
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*/
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void do_gettimeofday(struct timeval *tv)
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{
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unsigned long seq;
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unsigned long usec, sec;
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unsigned long max_ntp_tick;
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do {
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unsigned long lost;
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seq = read_seqbegin(&xtime_lock);
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usec = 0;
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lost = jiffies - wall_jiffies;
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/*
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* If time_adjust is negative then NTP is slowing the clock
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* so make sure not to go into next possible interval.
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* Better to lose some accuracy than have time go backwards..
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*/
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if (unlikely(time_adjust < 0)) {
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max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
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usec = min(usec, max_ntp_tick);
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if (lost)
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usec += lost * max_ntp_tick;
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}
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else if (unlikely(lost))
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usec += lost * (USEC_PER_SEC / HZ);
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sec = xtime.tv_sec;
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usec += (xtime.tv_nsec / 1000);
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} while (read_seqretry(&xtime_lock, seq));
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while (usec >= 1000000) {
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usec -= 1000000;
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sec++;
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}
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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}
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int do_settimeofday(struct timespec *tv)
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{
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time_t wtm_sec, sec = tv->tv_sec;
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long wtm_nsec, nsec = tv->tv_nsec;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irq(&xtime_lock);
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/*
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* This is revolting. We need to set "xtime" correctly. However, the
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* value in this location is the value at the most recent update of
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* wall time. Discover what correction gettimeofday() would have
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* made, and then undo it!
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*/
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nsec -= 0 * NSEC_PER_USEC;
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nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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set_normalized_timespec(&xtime, sec, nsec);
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set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
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time_adjust = 0; /* stop active adjtime() */
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time_status |= STA_UNSYNC;
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time_maxerror = NTP_PHASE_LIMIT;
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time_esterror = NTP_PHASE_LIMIT;
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write_sequnlock_irq(&xtime_lock);
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clock_was_set();
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return 0;
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}
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/*
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* Scheduler clock - returns current time in nanosec units.
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*/
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unsigned long long sched_clock(void)
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{
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return jiffies_64 * (1000000000 / HZ);
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}
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