sys/i386/isa/clock.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz and Don Ahn.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      from: @(#)clock.c       7.2 (Berkeley) 5/12/91
 *      $Id$
 */

/*
 * Primitive clock interrupt routines.
 */
#include "param.h"
#include "systm.h"
#include "time.h"
#include "kernel.h"
#include "machine/segments.h"
#include "i386/isa/icu.h"
#include "i386/isa/isa.h"
#include "i386/isa/rtc.h"
#include "i386/isa/timerreg.h"

#define DAYST 119
#define DAYEN 303

/* X-tals being what they are, it's nice to be able to fudge this one... */
/* Note, the name changed here from XTALSPEED to TIMER_FREQ rgrimes 4/26/93 */
#ifndef TIMER_FREQ
#define TIMER_FREQ      1193182 /* XXX - should be in isa.h */
#endif

startrtclock() {
        int s;

        findcpuspeed();         /* use the clock (while it's free)
                                        to find the cpu speed */
        /* initialize 8253 clock */
        outb(TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT);

        /* Correct rounding will buy us a better precision in timekeeping */
        outb (IO_TIMER1, (TIMER_FREQ+hz/2)/hz);
        outb (IO_TIMER1, ((TIMER_FREQ+hz/2)/hz)/256);

        /* initialize brain-dead battery powered clock */
        outb (IO_RTC, RTC_STATUSA);
        outb (IO_RTC+1, 0x26);
        outb (IO_RTC, RTC_STATUSB);
        outb (IO_RTC+1, 2);

        outb (IO_RTC, RTC_DIAG);
        if (s = inb (IO_RTC+1))
                printf("RTC BIOS diagnostic error %b\n", s, RTCDG_BITS);
        outb (IO_RTC, RTC_DIAG);
        outb (IO_RTC+1, 0);
}

unsigned int delaycount;        /* calibrated loop variable (1 millisecond) */

#define FIRST_GUESS     0x2000
findcpuspeed()
{
        unsigned char low;
        unsigned int remainder;

        /* Put counter in count down mode */
        outb(IO_TIMER1+3, 0x34);
        outb(IO_TIMER1, 0xff);
        outb(IO_TIMER1, 0xff);
        delaycount = FIRST_GUESS;
        spinwait(1);
        /* Read the value left in the counter */
        low     = inb(IO_TIMER1);       /* least siginifcant */
        remainder = inb(IO_TIMER1);     /* most significant */
        remainder = (remainder<<8) + low ;
        /* Formula for delaycount is :
         *  (loopcount * timer clock speed)/ (counter ticks * 1000)
         */
        delaycount = (FIRST_GUESS * (TIMER_FREQ/1000)) / (0xffff-remainder);
}


/* convert 2 digit BCD number */
bcd(i)
int i;
{
        return ((i/16)*10 + (i%16));
}

/* convert years to seconds (from 1970) */
unsigned long
ytos(y)
int y;
{
        int i;
        unsigned long ret;

        ret = 0;
        for(i = 1970; i < y; i++) {
                if (i % 4) ret += 365*24*60*60;
                else ret += 366*24*60*60;
        }
        return ret;
}

/* convert months to seconds */
unsigned long
mtos(m,leap)
int m,leap;
{
        int i;
        unsigned long ret;

        ret = 0;
        for(i=1;i<m;i++) {
                switch(i){
                case 1: case 3: case 5: case 7: case 8: case 10: case 12:
                        ret += 31*24*60*60; break;
                case 4: case 6: case 9: case 11:
                        ret += 30*24*60*60; break;
                case 2:
                        if (leap) ret += 29*24*60*60;
                        else ret += 28*24*60*60;
                }
        }
        return ret;
}


/*
 * Initialize the time of day register, based on the time base which is, e.g.
 * from a filesystem.
 */
inittodr(base)
        time_t base;
{
        unsigned long sec;
        int leap,day_week,t,yd;
        int sa,s;

        /* do we have a realtime clock present? (otherwise we loop below) */
        sa = rtcin(RTC_STATUSA);
        if (sa == 0xff || sa == 0) return;

        /* ready for a read? */
        while ((sa&RTCSA_TUP) == RTCSA_TUP)
                sa = rtcin(RTC_STATUSA);

        sec = bcd(rtcin(RTC_YEAR)) + 1900;
        if (sec < 1970)
                sec += 100;
        leap = !(sec % 4); sec = ytos(sec); /* year    */
        yd = mtos(bcd(rtcin(RTC_MONTH)),leap); sec += yd;       /* month   */
        t = (bcd(rtcin(RTC_DAY))-1) * 24*60*60; sec += t; yd += t; /* date    */
        day_week = rtcin(RTC_WDAY);                             /* day     */
        sec += bcd(rtcin(RTC_HRS)) * 60*60;                     /* hour    */
        sec += bcd(rtcin(RTC_MIN)) * 60;                        /* minutes */
        sec += bcd(rtcin(RTC_SEC));                             /* seconds */

        /* XXX off by one? Need to calculate DST on SUNDAY */
        /* Perhaps we should have the RTC hold GMT time to save */
        /* us the bother of converting. */
        yd = yd / (24*60*60);
        if ((yd >= DAYST) && ( yd <= DAYEN)) {
                sec -= 60*60;
        }
        sec += tz.tz_minuteswest * 60;

        time.tv_sec = sec;
}

#ifdef garbage
/*
 * Initialze the time of day register, based on the time base which is, e.g.
 * from a filesystem.
 */
test_inittodr(base)
        time_t base;
{

        outb(IO_RTC,9); /* year    */
        printf("%d ",bcd(inb(IO_RTC+1)));
        outb(IO_RTC,8); /* month   */
        printf("%d ",bcd(inb(IO_RTC+1)));
        outb(IO_RTC,7); /* day     */
        printf("%d ",bcd(inb(IO_RTC+1)));
        outb(IO_RTC,4); /* hour    */
        printf("%d ",bcd(inb(IO_RTC+1)));
        outb(IO_RTC,2); /* minutes */
        printf("%d ",bcd(inb(IO_RTC+1)));
        outb(IO_RTC,0); /* seconds */
        printf("%d\n",bcd(inb(IO_RTC+1)));

        time.tv_sec = base;
}
#endif

/*
 * Restart the clock.
 */
resettodr()
{
}

/*
 * Wire clock interrupt in.
 */
#define V(s)    __CONCAT(V, s)
extern V(clk)();
enablertclock() {
        setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
        INTREN(IRQ0);
}

/*
 * Delay for some number of milliseconds.
 */
void
spinwait(millisecs)
        int millisecs;
{
        DELAY(1000 * millisecs);
}