/* *  linux/arch/m68k/kernel/time.c * *  Copyright (C) 1991, 1992, 1995  Linus Torvalds * * This file contains the m68k-specific time handling details. * Most of the stuff is located in the machine specific files. * * 1997-09-10	Updated NTP code according to technical memorandum Jan '96 *		"A Kernel Model for Precision Timekeeping" by Dave Mills */#include <linux/config.h> /* CONFIG_HEARTBEAT */#include <linux/errno.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/param.h>#include <linux/string.h>#include <linux/mm.h>#include <linux/rtc.h>#include <asm/machdep.h>#include <asm/io.h>#include <linux/time.h>#include <linux/timex.h>#include <linux/profile.h>static inline int set_rtc_mmss(unsigned long nowtime){  if (mach_set_clock_mmss)    return mach_set_clock_mmss (nowtime);  return -1;}/* * timer_interrupt() needs to keep up the real-time clock, * as well as call the "do_timer()" routine every clocktick */static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs){	do_timer(regs);#ifndef CONFIG_SMP	update_process_times(user_mode(regs));#endif	profile_tick(CPU_PROFILING, regs);#ifdef CONFIG_HEARTBEAT	/* use power LED as a heartbeat instead -- much more useful	   for debugging -- based on the version for PReP by Cort */	/* acts like an actual heart beat -- ie thump-thump-pause... */	if (mach_heartbeat) {	    static unsigned cnt = 0, period = 0, dist = 0;	    if (cnt == 0 || cnt == dist)		mach_heartbeat( 1 );	    else if (cnt == 7 || cnt == dist+7)		mach_heartbeat( 0 );	    if (++cnt > period) {		cnt = 0;		/* The hyperbolic function below modifies the heartbeat period		 * length in dependency of the current (5min) load. It goes		 * through the points f(0)=126, f(1)=86, f(5)=51,		 * f(inf)->30. */		period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;		dist = period / 4;	    }	}#endif /* CONFIG_HEARTBEAT */	return IRQ_HANDLED;}void time_init(void){	struct rtc_time time;	if (mach_hwclk) {		mach_hwclk(0, &time);		if ((time.tm_year += 1900) < 1970)			time.tm_year += 100;		xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,				      time.tm_hour, time.tm_min, time.tm_sec);		xtime.tv_nsec = 0;	}	wall_to_monotonic.tv_sec = -xtime.tv_sec;	mach_sched_init(timer_interrupt);}/* * This version of gettimeofday has near microsecond resolution. */void do_gettimeofday(struct timeval *tv){	unsigned long flags;	extern unsigned long wall_jiffies;	unsigned long seq;	unsigned long usec, sec, lost;	unsigned long max_ntp_tick = tick_usec - tickadj;	do {		seq = read_seqbegin_irqsave(&xtime_lock, flags);		usec = mach_gettimeoffset();		lost = jiffies - wall_jiffies;		/*		 * If time_adjust is negative then NTP is slowing the clock		 * so make sure not to go into next possible interval.		 * Better to lose some accuracy than have time go backwards..		 */		if (unlikely(time_adjust < 0)) {			usec = min(usec, max_ntp_tick);			if (lost)				usec += lost * max_ntp_tick;		}		else if (unlikely(lost))			usec += lost * tick_usec;		sec = xtime.tv_sec;		usec += xtime.tv_nsec/1000;	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));	while (usec >= 1000000) {		usec -= 1000000;		sec++;	}	tv->tv_sec = sec;	tv->tv_usec = usec;}EXPORT_SYMBOL(do_gettimeofday);int do_settimeofday(struct timespec *tv){	time_t wtm_sec, sec = tv->tv_sec;	long wtm_nsec, nsec = tv->tv_nsec;	extern unsigned long wall_jiffies;	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)		return -EINVAL;	write_seqlock_irq(&xtime_lock);	/* This is revolting. We need to set the xtime.tv_nsec	 * correctly. However, the value in this location is	 * is value at the last tick.	 * Discover what correction gettimeofday	 * would have done, and then undo it!	 */	nsec -= 1000 * (mach_gettimeoffset() +			(jiffies - wall_jiffies) * (1000000 / HZ));	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);	set_normalized_timespec(&xtime, sec, nsec);	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);	ntp_clear();	write_sequnlock_irq(&xtime_lock);	clock_was_set();	return 0;}EXPORT_SYMBOL(do_settimeofday);/* * Scheduler clock - returns current time in ns units. */unsigned long long sched_clock(void){       return (unsigned long long)jiffies*(1000000000/HZ);}