162 lines
3.9 KiB
C
162 lines
3.9 KiB
C
/*
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* linux/arch/m68k/kernel/time.c
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*
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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*
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* This file contains the m68k-specific time handling details.
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* Most of the stuff is located in the machine specific files.
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*
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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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/rtc.h>
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#include <asm/machdep.h>
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#include <asm/io.h>
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#include <asm/irq_regs.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <linux/profile.h>
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static inline int set_rtc_mmss(unsigned long nowtime)
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{
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if (mach_set_clock_mmss)
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return mach_set_clock_mmss (nowtime);
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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)
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{
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do_timer(1);
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#ifndef CONFIG_SMP
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update_process_times(user_mode(get_irq_regs()));
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#endif
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profile_tick(CPU_PROFILING);
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#ifdef CONFIG_HEARTBEAT
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/* use power LED as a heartbeat instead -- much more useful
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for debugging -- based on the version for PReP by Cort */
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/* acts like an actual heart beat -- ie thump-thump-pause... */
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if (mach_heartbeat) {
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static unsigned cnt = 0, period = 0, dist = 0;
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if (cnt == 0 || cnt == dist)
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mach_heartbeat( 1 );
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else if (cnt == 7 || cnt == dist+7)
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mach_heartbeat( 0 );
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if (++cnt > period) {
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cnt = 0;
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/* The hyperbolic function below modifies the heartbeat period
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* length in dependency of the current (5min) load. It goes
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* through the points f(0)=126, f(1)=86, f(5)=51,
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* f(inf)->30. */
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period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
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dist = period / 4;
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}
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}
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#endif /* CONFIG_HEARTBEAT */
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return IRQ_HANDLED;
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}
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void __init time_init(void)
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{
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struct rtc_time time;
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if (mach_hwclk) {
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mach_hwclk(0, &time);
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if ((time.tm_year += 1900) < 1970)
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time.tm_year += 100;
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xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
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time.tm_hour, time.tm_min, time.tm_sec);
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xtime.tv_nsec = 0;
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}
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wall_to_monotonic.tv_sec = -xtime.tv_sec;
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mach_sched_init(timer_interrupt);
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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 flags;
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unsigned long seq;
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unsigned long usec, sec;
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unsigned long max_ntp_tick = tick_usec - tickadj;
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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usec = mach_gettimeoffset();
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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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usec = min(usec, max_ntp_tick);
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sec = xtime.tv_sec;
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usec += xtime.tv_nsec/1000;
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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 -= 1000 * mach_gettimeoffset();
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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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ntp_clear();
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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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