2005-04-16 16:20:36 -06:00
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/*
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* arch/s390/kernel/time.c
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* Time of day based timer functions.
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Hartmut Penner (hp@de.ibm.com),
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* Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
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*
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* Derived from "arch/i386/kernel/time.c"
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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*/
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#include <linux/errno.h>
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#include <linux/module.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/mm.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/types.h>
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#include <linux/profile.h>
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#include <linux/timex.h>
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#include <linux/notifier.h>
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#include <asm/uaccess.h>
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#include <asm/delay.h>
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#include <asm/s390_ext.h>
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#include <asm/div64.h>
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#include <asm/irq.h>
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2006-10-06 08:38:35 -06:00
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#include <asm/irq_regs.h>
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2005-04-16 16:20:36 -06:00
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#include <asm/timer.h>
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/* change this if you have some constant time drift */
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#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
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#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
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/*
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* Create a small time difference between the timer interrupts
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* on the different cpus to avoid lock contention.
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*/
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#define CPU_DEVIATION (smp_processor_id() << 12)
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#define TICK_SIZE tick
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static ext_int_info_t ext_int_info_cc;
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static u64 init_timer_cc;
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static u64 jiffies_timer_cc;
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static u64 xtime_cc;
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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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2006-02-01 04:06:32 -07:00
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return ((get_clock() - jiffies_timer_cc) * 125) >> 9;
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2005-04-16 16:20:36 -06:00
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}
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2006-02-01 04:06:33 -07:00
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/*
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* Monotonic_clock - returns # of nanoseconds passed since time_init()
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*/
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unsigned long long monotonic_clock(void)
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{
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return sched_clock();
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}
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EXPORT_SYMBOL(monotonic_clock);
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2005-04-16 16:20:36 -06:00
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void tod_to_timeval(__u64 todval, struct timespec *xtime)
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{
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unsigned long long sec;
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sec = todval >> 12;
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do_div(sec, 1000000);
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xtime->tv_sec = sec;
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todval -= (sec * 1000000) << 12;
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xtime->tv_nsec = ((todval * 1000) >> 12);
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}
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static inline unsigned long do_gettimeoffset(void)
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{
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__u64 now;
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2006-10-01 00:28:31 -06:00
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now = (get_clock() - jiffies_timer_cc) >> 12;
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now -= (__u64) jiffies * USECS_PER_JIFFY;
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2005-04-16 16:20:36 -06:00
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return (unsigned long) now;
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}
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/*
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* This version of gettimeofday has 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 flags;
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unsigned long seq;
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unsigned long usec, sec;
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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sec = xtime.tv_sec;
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usec = xtime.tv_nsec / 1000 + do_gettimeoffset();
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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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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EXPORT_SYMBOL(do_gettimeofday);
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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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/* This is revolting. We need to set the xtime.tv_nsec
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* correctly. However, the value in this location is
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* is value at the last tick.
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* Discover what correction gettimeofday
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* would have done, and then undo it!
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*/
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nsec -= do_gettimeoffset() * 1000;
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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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2005-09-06 16:17:46 -06:00
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ntp_clear();
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2005-04-16 16:20:36 -06:00
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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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EXPORT_SYMBOL(do_settimeofday);
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#ifdef CONFIG_PROFILING
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2006-10-06 08:38:35 -06:00
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#define s390_do_profile() profile_tick(CPU_PROFILING)
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2005-04-16 16:20:36 -06:00
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#else
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2006-10-06 08:38:35 -06:00
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#define s390_do_profile() do { ; } while(0)
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2005-04-16 16:20:36 -06:00
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#endif /* CONFIG_PROFILING */
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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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2006-10-06 08:38:35 -06:00
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void account_ticks(void)
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2005-04-16 16:20:36 -06:00
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{
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__u64 tmp;
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2006-09-29 03:00:32 -06:00
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__u32 ticks;
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2005-04-16 16:20:36 -06:00
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/* Calculate how many ticks have passed. */
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if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) {
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/*
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* We have to program the clock comparator even if
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* no tick has passed. That happens if e.g. an i/o
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* interrupt wakes up an idle processor that has
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* switched off its hz timer.
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*/
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tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
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asm volatile ("SCKC %0" : : "m" (tmp));
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return;
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}
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tmp = S390_lowcore.int_clock - S390_lowcore.jiffy_timer;
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if (tmp >= 2*CLK_TICKS_PER_JIFFY) { /* more than two ticks ? */
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ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
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S390_lowcore.jiffy_timer +=
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CLK_TICKS_PER_JIFFY * (__u64) ticks;
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} else if (tmp >= CLK_TICKS_PER_JIFFY) {
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ticks = 2;
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S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
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} else {
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ticks = 1;
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S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
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}
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/* set clock comparator for next tick */
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tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
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asm volatile ("SCKC %0" : : "m" (tmp));
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#ifdef CONFIG_SMP
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/*
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* Do not rely on the boot cpu to do the calls to do_timer.
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* Spread it over all cpus instead.
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*/
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write_seqlock(&xtime_lock);
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if (S390_lowcore.jiffy_timer > xtime_cc) {
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2006-09-29 03:00:32 -06:00
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__u32 xticks;
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2005-04-16 16:20:36 -06:00
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tmp = S390_lowcore.jiffy_timer - xtime_cc;
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if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
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xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
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xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
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} else {
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xticks = 1;
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xtime_cc += CLK_TICKS_PER_JIFFY;
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}
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2006-09-29 03:00:32 -06:00
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do_timer(xticks);
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2005-04-16 16:20:36 -06:00
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}
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write_sequnlock(&xtime_lock);
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#else
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2006-09-29 03:00:32 -06:00
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do_timer(ticks);
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2005-04-16 16:20:36 -06:00
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#endif
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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2006-01-14 14:21:03 -07:00
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account_tick_vtime(current);
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2005-04-16 16:20:36 -06:00
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#else
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while (ticks--)
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2006-10-06 08:38:35 -06:00
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update_process_times(user_mode(get_irq_regs()));
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2005-04-16 16:20:36 -06:00
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#endif
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2006-10-06 08:38:35 -06:00
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s390_do_profile();
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2005-04-16 16:20:36 -06:00
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}
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#ifdef CONFIG_NO_IDLE_HZ
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#ifdef CONFIG_NO_IDLE_HZ_INIT
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int sysctl_hz_timer = 0;
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#else
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int sysctl_hz_timer = 1;
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#endif
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/*
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* Stop the HZ tick on the current CPU.
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* Only cpu_idle may call this function.
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*/
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static inline void stop_hz_timer(void)
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{
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2005-11-07 01:59:02 -07:00
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unsigned long flags;
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unsigned long seq, next;
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2005-05-01 09:58:57 -06:00
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__u64 timer, todval;
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2006-05-15 10:43:59 -06:00
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int cpu = smp_processor_id();
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2005-04-16 16:20:36 -06:00
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if (sysctl_hz_timer != 0)
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return;
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2006-05-15 10:43:59 -06:00
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cpu_set(cpu, nohz_cpu_mask);
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2005-04-16 16:20:36 -06:00
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/*
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* Leave the clock comparator set up for the next timer
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* tick if either rcu or a softirq is pending.
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*/
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2006-05-15 10:43:59 -06:00
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if (rcu_needs_cpu(cpu) || local_softirq_pending()) {
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cpu_clear(cpu, nohz_cpu_mask);
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2005-04-16 16:20:36 -06:00
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return;
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}
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/*
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* This cpu is going really idle. Set up the clock comparator
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* for the next event.
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*/
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2005-11-07 01:59:02 -07:00
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next = next_timer_interrupt();
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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2006-05-23 01:22:42 -06:00
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timer = ((__u64) next) - ((__u64) jiffies) + jiffies_64;
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2005-11-07 01:59:02 -07:00
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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2005-05-01 09:58:57 -06:00
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todval = -1ULL;
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/* Be careful about overflows. */
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if (timer < (-1ULL / CLK_TICKS_PER_JIFFY)) {
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timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
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if (timer >= jiffies_timer_cc)
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todval = timer;
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}
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asm volatile ("SCKC %0" : : "m" (todval));
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2005-04-16 16:20:36 -06:00
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}
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/*
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* Start the HZ tick on the current CPU.
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* Only cpu_idle may call this function.
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*/
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static inline void start_hz_timer(void)
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{
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2006-10-06 08:38:35 -06:00
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BUG_ON(!in_interrupt());
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2005-04-16 16:20:36 -06:00
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if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
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return;
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2006-10-06 08:38:35 -06:00
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account_ticks();
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2005-04-16 16:20:36 -06:00
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cpu_clear(smp_processor_id(), nohz_cpu_mask);
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}
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static int nohz_idle_notify(struct notifier_block *self,
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unsigned long action, void *hcpu)
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{
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switch (action) {
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case CPU_IDLE:
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stop_hz_timer();
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break;
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case CPU_NOT_IDLE:
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start_hz_timer();
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block nohz_idle_nb = {
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.notifier_call = nohz_idle_notify,
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};
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void __init nohz_init(void)
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{
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if (register_idle_notifier(&nohz_idle_nb))
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panic("Couldn't register idle notifier");
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}
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#endif
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/*
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* Start the clock comparator on the current CPU.
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*/
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void init_cpu_timer(void)
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{
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unsigned long cr0;
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__u64 timer;
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timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
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S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY;
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timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
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asm volatile ("SCKC %0" : : "m" (timer));
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/* allow clock comparator timer interrupt */
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__ctl_store(cr0, 0, 0);
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cr0 |= 0x800;
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__ctl_load(cr0, 0, 0);
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}
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extern void vtime_init(void);
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/*
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* Initialize the TOD clock and the CPU timer of
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* the boot cpu.
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*/
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void __init time_init(void)
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{
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__u64 set_time_cc;
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int cc;
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/* kick the TOD clock */
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2006-09-28 08:56:43 -06:00
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asm volatile(
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" stck 0(%2)\n"
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" ipm %0\n"
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" srl %0,28"
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: "=d" (cc), "=m" (init_timer_cc)
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: "a" (&init_timer_cc) : "cc");
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2005-04-16 16:20:36 -06:00
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switch (cc) {
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case 0: /* clock in set state: all is fine */
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break;
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case 1: /* clock in non-set state: FIXME */
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printk("time_init: TOD clock in non-set state\n");
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break;
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case 2: /* clock in error state: FIXME */
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printk("time_init: TOD clock in error state\n");
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break;
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case 3: /* clock in stopped or not-operational state: FIXME */
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printk("time_init: TOD clock stopped/non-operational\n");
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break;
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}
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jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;
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/* set xtime */
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xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
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set_time_cc = init_timer_cc - 0x8126d60e46000000LL +
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(0x3c26700LL*1000000*4096);
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tod_to_timeval(set_time_cc, &xtime);
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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/* request the clock comparator external interrupt */
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2006-07-12 08:41:55 -06:00
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if (register_early_external_interrupt(0x1004, NULL,
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2005-04-16 16:20:36 -06:00
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&ext_int_info_cc) != 0)
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panic("Couldn't request external interrupt 0x1004");
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init_cpu_timer();
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#ifdef CONFIG_NO_IDLE_HZ
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nohz_init();
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#endif
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#ifdef CONFIG_VIRT_TIMER
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vtime_init();
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#endif
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}
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