![Linus Torvalds](/assets/img/avatar_default.png)
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
199 lines
5 KiB
C
199 lines
5 KiB
C
/*
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* linux/arch/m68knommu/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/config.h>
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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/profile.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <asm/machdep.h>
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#include <asm/io.h>
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#define TICK_SIZE (tick_nsec / 1000)
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u64 jiffies_64 = INITIAL_JIFFIES;
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EXPORT_SYMBOL(jiffies_64);
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extern unsigned long wall_jiffies;
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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, 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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/* may need to kick the hardware timer */
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if (mach_tick)
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mach_tick();
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write_seqlock(&xtime_lock);
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do_timer(regs);
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#ifndef CONFIG_SMP
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update_process_times(user_mode(regs));
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#endif
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if (current->pid)
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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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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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/* 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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write_sequnlock(&xtime_lock);
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return(IRQ_HANDLED);
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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,
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int *min, int *sec);
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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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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 lost, 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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usec = mach_gettimeoffset ? mach_gettimeoffset() : 0;
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lost = jiffies - wall_jiffies;
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if (lost)
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usec += lost * (1000000 / 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_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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/*
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* This is revolting. We need to set the xtime.tv_usec
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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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if (mach_gettimeoffset)
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nsec -= (mach_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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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 (unsigned long long)jiffies * (1000000000 / HZ);
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}
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EXPORT_SYMBOL(do_settimeofday);
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