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/*

 *  linux/arch/m68knommu/kernel/time.c

 *

 *  Copyright (C) 1998  D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,

 *                      Kenneth Albanowski <kjahds@kjahds.com>,

 *                      The Silver Hammer Group, Ltd.

 *

 *  Copied/hacked from:

 *

 *  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.

 */

#include <linux/config.h>

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/kernel.h>

#include <linux/param.h>

#include <linux/string.h>

#include <linux/mm.h>

#include <asm/machdep.h>

#include <asm/segment.h>

#include <asm/io.h>

#include <linux/timex.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

 */

void timer_interrupt(int irq, void *dummy, struct pt_regs * regs)

{

        /* last time the cmos clock got updated */

        static long last_rtc_update=0;

        /* may need to kick the hardware timer */

        if (mach_tick)

          mach_tick();

        do_timer(regs);

        /*

         * If we have an externally synchronized Linux clock, then update

         * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be

         * called as close as possible to 500 ms before the new second starts.

         */

        if (time_state != TIME_BAD && xtime.tv_sec > last_rtc_update + 660 &&

            xtime.tv_usec > 500000 - (tick >> 1) &&

            xtime.tv_usec < 500000 + (tick >> 1)) {

          if (set_rtc_mmss(xtime.tv_sec) == 0)

            last_rtc_update = xtime.tv_sec;

          else

            last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */

        }

}

/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.

 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59

 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.

 *

 * [For the Julian calendar (which was used in Russia before 1917,

 * Britain & colonies before 1752, anywhere else before 1582,

 * and is still in use by some communities) leave out the

 * -year/100+year/400 terms, and add 10.]

 *

 * This algorithm was first published by Gauss (I think).

 *

 * WARNING: this function will overflow on 2106-02-07 06:28:16 on

 * machines were long is 32-bit! (However, as time_t is signed, we

 * will already get problems at other places on 2038-01-19 03:14:08)

 */

static inline unsigned long mktime(unsigned int year, unsigned int mon,

        unsigned int day, unsigned int hour,

        unsigned int min, unsigned int sec)

{

        if (0 >= (int) (mon -= 2)) {     /* 1..12 -> 11,12,1..10 */

                mon += 12;      /* Puts Feb last since it has leap day */

                year -= 1;

        }

        return (((

            (unsigned long)(year/4 - year/100 + year/400 + 367*mon/12 + day) +

              year*365 - 719499

            )*24 + hour /* now have hours */

           )*60 + min /* now have minutes */

          )*60 + sec; /* finally seconds */

}

void time_init(void)

{

        unsigned int year, mon, day, hour, min, sec;

        extern void arch_gettod(int *year, int *mon, int *day, int *hour,

                                int *min, int *sec);

        arch_gettod (&year, &mon, &day, &hour, &min, &sec);

        if ((year += 1900) < 1970)

                year += 100;

        xtime.tv_sec = mktime(year, mon, day, hour, min, sec);

        xtime.tv_usec = 0;

        if (mach_sched_init)

                mach_sched_init(timer_interrupt);

}

/*

 * This version of gettimeofday has near microsecond resolution.

 */

void do_gettimeofday(struct timeval *tv)

{

        unsigned long flags;

        save_flags(flags);

        cli();

        *tv = xtime;

        if (mach_gettimeoffset) {

          tv->tv_usec += mach_gettimeoffset();

          if (tv->tv_usec >= 1000000) {

            tv->tv_usec -= 1000000;

            tv->tv_sec++;

          }

        }

        restore_flags(flags);

}

void do_settimeofday(struct timeval *tv)

{

        cli();

        /* This is revolting. We need to set the xtime.tv_usec

         * 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!

         */

        if (mach_gettimeoffset)

          tv->tv_usec -= mach_gettimeoffset();

        if (tv->tv_usec < 0) {

                tv->tv_usec += 1000000;

                tv->tv_sec--;

        }

        xtime = *tv;

        time_state = TIME_BAD;

        time_maxerror = MAXPHASE;

        time_esterror = MAXPHASE;

        sti();

}