9ad380ab4c
the NTP kernel PLL is disabled, and acquire_timer0() is enabled, thus opening the door for microtime() (and hence gettimeofday()) to return bogus timestamps. This option is necessary for the `pca' driver to work, but is implemented to underscore the fact that accurate timekeeping and the `pca' driver are incompatible at present. If someone writes a version of microtime() that works when the `pca' driver is being used, this can get junked.
441 lines
10 KiB
C
441 lines
10 KiB
C
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* William Jolitz and Don Ahn.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
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* $Id: clock.c,v 1.7 1994/04/21 14:19:16 sos Exp $
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*/
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/*
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* Primitive clock interrupt routines.
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*/
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#include "param.h"
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#include "systm.h"
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#include "time.h"
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#include "kernel.h"
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#include "machine/segments.h"
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#include "machine/frame.h"
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#include "i386/isa/icu.h"
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#include "i386/isa/isa.h"
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#include "i386/isa/rtc.h"
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#include "i386/isa/timerreg.h"
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/* X-tals being what they are, it's nice to be able to fudge this one... */
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/* Note, the name changed here from XTALSPEED to TIMER_FREQ rgrimes 4/26/93 */
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#ifndef TIMER_FREQ
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#define TIMER_FREQ 1193182 /* XXX - should be in isa.h */
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#endif
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#define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
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void hardclock();
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static void findcpuspeed(void);
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static char timer0_in_use = 0, timer2_in_use = 0;
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static int timer0_rate = 100; /* XXX should be hz */
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static void (*timer_func)() = hardclock;
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static unsigned int prescale = 0;
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static unsigned int hardclock_prescale;
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static int beeping;
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unsigned int delaycount; /* calibrated loop variable (1 millisecond) */
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void
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timerintr(struct intrframe frame)
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{
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timer_func(frame);
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if (timer0_in_use)
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if (prescale++ >= hardclock_prescale) {
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hardclock(frame);
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prescale = 0;
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}
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}
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int
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acquire_timer0(int rate, void (*function)() )
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{
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#ifndef INACCURATE_MICROTIME_IS_OK
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return -1;
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#else
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if (timer0_in_use) /* XXX || (rate < 20000 && rate % hz)) */
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return -1;
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timer0_in_use = 1;
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timer0_rate = rate;
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prescale = 0;
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hardclock_prescale = rate/hz;
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outb(TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT);
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outb(TIMER_CNTR0, TIMER_DIV(rate)%256);
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outb(TIMER_CNTR0, TIMER_DIV(rate)/256);
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if (function)
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timer_func = function;
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return 0;
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#endif
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}
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int
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acquire_timer2(int mode)
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{
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if (timer2_in_use)
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return -1;
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timer2_in_use = 1;
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outb(TIMER_MODE, TIMER_SEL2 | (mode &0x3f));
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return 0;
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}
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int
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release_timer0()
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{
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if (!timer0_in_use)
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return -1;
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timer0_in_use = 0;
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timer0_rate = hz;
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outb(TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT);
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outb(TIMER_CNTR0, TIMER_DIV(hz)%256);
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outb(TIMER_CNTR0, TIMER_DIV(hz)/256);
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timer_func = hardclock;
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return 0;
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}
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int
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release_timer2()
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{
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if (!timer2_in_use)
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return -1;
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timer2_in_use = 0;
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outb(TIMER_MODE, TIMER_SEL2|TIMER_SQWAVE|TIMER_16BIT);
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return 0;
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}
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static int
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getit()
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{
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int high, low;
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disable_intr();
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/* select timer0 and latch counter value */
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outb(TIMER_MODE, TIMER_SEL0);
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low = inb(TIMER_CNTR0);
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high = inb(TIMER_CNTR0);
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enable_intr();
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return ((high << 8) | low);
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}
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/*
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* Wait "n" microseconds.
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* Relies on timer 1 counting down from (TIMER_FREQ / hz)
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* Note: timer had better have been programmed before this is first used!
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*/
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void
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DELAY(int n)
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{
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int counter_limit, prev_tick, tick, ticks_left, sec, usec;
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#ifdef DELAYDEBUG
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int getit_calls = 1;
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int n1;
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static int state = 0;
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if (state == 0) {
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state = 1;
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for (n1 = 1; n1 <= 10000000; n1 *= 10)
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DELAY(n1);
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state = 2;
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}
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if (state == 1)
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printf("DELAY(%d)...", n);
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#endif
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/*
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* Read the counter first, so that the rest of the setup overhead is
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* counted. Guess the initial overhead is 20 usec (on most systems it
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* takes about 1.5 usec for each of the i/o's in getit(). The loop
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* takes about 6 usec on a 486/33 and 13 usec on a 386/20. The
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* multiplications and divisions to scale the count take a while).
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*/
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prev_tick = getit(0, 0);
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n -= 20;
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/*
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* Calculate (n * (TIMER_FREQ / 1e6)) without using floating point
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* and without any avoidable overflows.
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*/
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sec = n / 1000000;
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usec = n - sec * 1000000;
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ticks_left = sec * TIMER_FREQ
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+ usec * (TIMER_FREQ / 1000000)
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+ usec * ((TIMER_FREQ % 1000000) / 1000) / 1000
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+ usec * (TIMER_FREQ % 1000) / 1000000;
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counter_limit = TIMER_FREQ/timer0_rate;
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while (ticks_left > 0) {
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tick = getit(0, 0);
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#ifdef DELAYDEBUG
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++getit_calls;
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#endif
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if (tick > prev_tick)
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ticks_left -= prev_tick - (tick - counter_limit);
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else
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ticks_left -= prev_tick - tick;
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prev_tick = tick;
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}
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#ifdef DELAYDEBUG
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if (state == 1)
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printf(" %d calls to getit() at %d usec each\n",
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getit_calls, (n + 5) / getit_calls);
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#endif
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}
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static void
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sysbeepstop() /* SOS XXX dummy is not needed */
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{
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outb(IO_PPI, inb(IO_PPI)&0xFC); /* disable counter2 output to speaker */
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release_timer2();
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beeping = 0;
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}
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int
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sysbeep(int pitch, int period)
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{
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if (acquire_timer2(TIMER_SQWAVE|TIMER_16BIT))
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return -1;
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outb(TIMER_CNTR2, pitch);
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outb(TIMER_CNTR2, (pitch>>8));
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if (!beeping) {
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outb(IO_PPI, inb(IO_PPI) | 3); /* enable counter2 output to speaker */
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beeping = period;
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timeout(sysbeepstop, 0, period);
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}
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return 0;
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}
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void
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startrtclock()
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{
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int s;
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findcpuspeed(); /* use the clock (while it's free)
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to find the cpu speed */
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/* initialize 8253 clock */
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outb(TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT);
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/* Correct rounding will buy us a better precision in timekeeping */
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outb (IO_TIMER1, TIMER_DIV(hz)%256);
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outb (IO_TIMER1, TIMER_DIV(hz)/256);
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timer0_rate = hz;
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/* initialize brain-dead battery powered clock */
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outb (IO_RTC, RTC_STATUSA);
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outb (IO_RTC+1, 0x26);
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outb (IO_RTC, RTC_STATUSB);
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outb (IO_RTC+1, 2);
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outb (IO_RTC, RTC_DIAG);
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if (s = inb (IO_RTC+1))
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printf("RTC BIOS diagnostic error %b\n", s, RTCDG_BITS);
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}
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#define FIRST_GUESS 0x2000
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static void
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findcpuspeed()
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{
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unsigned char low;
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unsigned int remainder;
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/* Put counter in count down mode */
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outb(TIMER_MODE, TIMER_16BIT|TIMER_RATEGEN);
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outb(IO_TIMER1, 0xff);
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outb(IO_TIMER1, 0xff);
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delaycount = FIRST_GUESS;
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spinwait(1);
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/* Read the value left in the counter */
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low = inb(IO_TIMER1); /* least siginifcant */
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remainder = inb(IO_TIMER1); /* most significant */
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remainder = (remainder<<8) + low ;
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/* Formula for delaycount is :
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* (loopcount * timer clock speed)/ (counter ticks * 1000)
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*/
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delaycount = (FIRST_GUESS * (TIMER_FREQ/1000)) / (0xffff-remainder);
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}
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/* convert 2 digit BCD number */
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int
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bcd(int i)
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{
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return ((i/16)*10 + (i%16));
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}
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/* convert years to seconds (from 1970) */
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unsigned long
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ytos(int y)
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{
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int i;
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unsigned long ret;
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ret = 0;
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for(i = 1970; i < y; i++) {
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if (i % 4) ret += 365*24*60*60;
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else ret += 366*24*60*60;
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}
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return ret;
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}
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/* convert months to seconds */
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unsigned long
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mtos(int m, int leap)
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{
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int i;
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unsigned long ret;
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ret = 0;
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for(i=1; i<m; i++) {
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switch(i){
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case 1: case 3: case 5: case 7: case 8: case 10: case 12:
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ret += 31*24*60*60; break;
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case 4: case 6: case 9: case 11:
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ret += 30*24*60*60; break;
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case 2:
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if (leap) ret += 29*24*60*60;
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else ret += 28*24*60*60;
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}
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}
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return ret;
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}
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/*
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* Initialize the time of day register, based on the time base which is, e.g.
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* from a filesystem.
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*/
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void
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inittodr(time_t base)
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{
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unsigned long sec;
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int leap, day_week, t, yd;
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int sa,s;
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/* do we have a realtime clock present? (otherwise we loop below) */
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sa = rtcin(RTC_STATUSA);
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if (sa == 0xff || sa == 0) return;
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/* ready for a read? */
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while ((sa&RTCSA_TUP) == RTCSA_TUP)
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sa = rtcin(RTC_STATUSA);
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sec = bcd(rtcin(RTC_YEAR)) + 1900;
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if (sec < 1970)
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sec += 100;
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leap = !(sec % 4); sec = ytos(sec); /* year */
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yd = mtos(bcd(rtcin(RTC_MONTH)),leap); sec+=yd; /* month */
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t = (bcd(rtcin(RTC_DAY))-1) * 24*60*60; sec+=t; yd+=t; /* date */
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day_week = rtcin(RTC_WDAY); /* day */
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sec += bcd(rtcin(RTC_HRS)) * 60*60; /* hour */
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sec += bcd(rtcin(RTC_MIN)) * 60; /* minutes */
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sec += bcd(rtcin(RTC_SEC)); /* seconds */
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sec += tz.tz_minuteswest * 60;
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time.tv_sec = sec;
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}
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#ifdef garbage
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/*
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* Initialze the time of day register, based on the time base which is, e.g.
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* from a filesystem.
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*/
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test_inittodr(time_t base)
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{
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outb(IO_RTC,9); /* year */
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printf("%d ",bcd(inb(IO_RTC+1)));
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outb(IO_RTC,8); /* month */
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printf("%d ",bcd(inb(IO_RTC+1)));
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outb(IO_RTC,7); /* day */
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printf("%d ",bcd(inb(IO_RTC+1)));
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outb(IO_RTC,4); /* hour */
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printf("%d ",bcd(inb(IO_RTC+1)));
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outb(IO_RTC,2); /* minutes */
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printf("%d ",bcd(inb(IO_RTC+1)));
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outb(IO_RTC,0); /* seconds */
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printf("%d\n",bcd(inb(IO_RTC+1)));
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time.tv_sec = base;
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}
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#endif
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/*
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* Restart the clock.
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*/
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void
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resettodr()
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{
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}
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/*
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* Wire clock interrupt in.
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*/
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#define V(s) __CONCAT(V, s)
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extern void V(clk)();
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void
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enablertclock()
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{
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setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
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INTREN(IRQ0);
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}
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/*
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* Delay for some number of milliseconds.
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*/
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void
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spinwait(int millisecs)
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{
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DELAY(1000 * millisecs);
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}
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