pcrtc.c revision 19248
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz and Don Ahn.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
37 *	$Id: clock.c,v 1.8 1996/10/23 07:25:13 asami Exp $
38 */
39
40/*
41 * inittodr, settodr and support routines written
42 * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>
43 *
44 * reintroduced and updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
45 */
46
47/*
48 * modified for PC98 by Kakefuda
49 */
50
51/*
52 * Primitive clock interrupt routines.
53 */
54
55#include "opt_clock.h"
56#include "opt_cpu.h"
57
58#include <sys/param.h>
59#include <sys/systm.h>
60#include <sys/time.h>
61#include <sys/kernel.h>
62#include <sys/sysctl.h>
63
64#include <machine/clock.h>
65#ifdef CLK_CALIBRATION_LOOP
66#include <machine/cons.h>
67#endif
68#include <machine/cpu.h>
69#include <machine/frame.h>
70
71#include <i386/isa/icu.h>
72#ifdef PC98
73#include <pc98/pc98/pc98.h>
74#include <i386/isa/isa_device.h>
75#include <pc98/pc98/timerreg.h>
76#else
77#include <i386/isa/isa.h>
78#include <i386/isa/isa_device.h>
79#include <i386/isa/rtc.h>
80#include <i386/isa/timerreg.h>
81#endif
82
83/*
84 * 32-bit time_t's can't reach leap years before 1904 or after 2036, so we
85 * can use a simple formula for leap years.
86 */
87#define	LEAPYEAR(y) ((u_int)(y) % 4 == 0)
88#define DAYSPERYEAR   (31+28+31+30+31+30+31+31+30+31+30+31)
89
90#define	TIMER_DIV(x) ((timer_freq + (x) / 2) / (x))
91
92/*
93 * Time in timer cycles that it takes for microtime() to disable interrupts
94 * and latch the count.  microtime() currently uses "cli; outb ..." so it
95 * normally takes less than 2 timer cycles.  Add a few for cache misses.
96 * Add a few more to allow for latency in bogus calls to microtime() with
97 * interrupts already disabled.
98 */
99#define	TIMER0_LATCH_COUNT	20
100
101/*
102 * Maximum frequency that we are willing to allow for timer0.  Must be
103 * low enough to guarantee that the timer interrupt handler returns
104 * before the next timer interrupt.  Must result in a lower TIMER_DIV
105 * value than TIMER0_LATCH_COUNT so that we don't have to worry about
106 * underflow in the calculation of timer0_overflow_threshold.
107 */
108#define	TIMER0_MAX_FREQ		20000
109
110int	adjkerntz;		/* local offset	from GMT in seconds */
111int	disable_rtc_set;	/* disable resettodr() if != 0 */
112int	wall_cmos_clock;	/* wall	CMOS clock assumed if != 0 */
113
114u_int	idelayed;
115#if defined(I586_CPU) || defined(I686_CPU)
116u_int 	i586_ctr_bias;
117u_int	i586_ctr_comultiplier;
118u_int	i586_ctr_freq;
119u_int	i586_ctr_multiplier;
120long long	i586_last_tick;
121unsigned long	i586_avg_tick;
122#endif
123int	statclock_disable;
124u_int	stat_imask = SWI_CLOCK_MASK;
125#ifdef TIMER_FREQ
126static	u_int	timer_freq = TIMER_FREQ;
127#else
128#ifdef PC98
129#ifndef AUTO_CLOCK
130#ifndef PC98_8M
131static	u_int	timer_freq = 2457600;
132#else	/* !PC98_8M */
133static	u_int	timer_freq = 1996800;
134#endif	/* PC98_8M */
135#else	/* AUTO_CLOCK */
136static	u_int	timer_freq = 2457600;
137#endif	/* AUTO_CLOCK */
138#else /* IBM-PC */
139static	u_int	timer_freq = 1193182;
140#endif /* PC98 */
141#endif
142int 	timer0_max_count;
143u_int 	timer0_overflow_threshold;
144u_int 	timer0_prescaler_count;
145
146static	int	beeping = 0;
147static	u_int	clk_imask = HWI_MASK | SWI_MASK;
148static	const u_char daysinmonth[] = {31,28,31,30,31,30,31,31,30,31,30,31};
149static 	u_int	hardclock_max_count;
150/*
151 * XXX new_function and timer_func should not handle clockframes, but
152 * timer_func currently needs to hold hardclock to handle the
153 * timer0_state == 0 case.  We should use register_intr()/unregister_intr()
154 * to switch between clkintr() and a slightly different timerintr().
155 */
156static 	void	(*new_function) __P((struct clockframe *frame));
157static 	u_int	new_rate;
158#ifndef PC98
159static	u_char	rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
160static	u_char	rtc_statusb = RTCSB_24HR | RTCSB_PINTR;
161#endif
162
163/* Values for timerX_state: */
164#define	RELEASED	0
165#define	RELEASE_PENDING	1
166#define	ACQUIRED	2
167#define	ACQUIRE_PENDING	3
168
169static 	u_char	timer0_state;
170#ifdef	PC98
171static 	u_char	timer1_state;
172#endif
173static	u_char	timer2_state;
174static 	void	(*timer_func) __P((struct clockframe *frame)) = hardclock;
175int		rtc_inb __P((void));
176
177#if defined(I586_CPU) || defined(I686_CPU)
178static	void	set_i586_ctr_freq(u_int i586_freq, u_int i8254_freq);
179#endif
180
181static void
182clkintr(struct clockframe frame)
183{
184	timer_func(&frame);
185	switch (timer0_state) {
186
187	case RELEASED:
188		setdelayed();
189		break;
190
191	case ACQUIRED:
192		if ((timer0_prescaler_count += timer0_max_count)
193		    >= hardclock_max_count) {
194			hardclock(&frame);
195			setdelayed();
196			timer0_prescaler_count -= hardclock_max_count;
197		}
198		break;
199
200	case ACQUIRE_PENDING:
201		setdelayed();
202		timer0_max_count = TIMER_DIV(new_rate);
203		timer0_overflow_threshold =
204			timer0_max_count - TIMER0_LATCH_COUNT;
205		disable_intr();
206		outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
207		outb(TIMER_CNTR0, timer0_max_count & 0xff);
208		outb(TIMER_CNTR0, timer0_max_count >> 8);
209		enable_intr();
210		timer0_prescaler_count = 0;
211		timer_func = new_function;
212		timer0_state = ACQUIRED;
213		break;
214
215	case RELEASE_PENDING:
216		if ((timer0_prescaler_count += timer0_max_count)
217		    >= hardclock_max_count) {
218			hardclock(&frame);
219			setdelayed();
220			timer0_max_count = hardclock_max_count;
221			timer0_overflow_threshold =
222				timer0_max_count - TIMER0_LATCH_COUNT;
223			disable_intr();
224			outb(TIMER_MODE,
225			     TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
226			outb(TIMER_CNTR0, timer0_max_count & 0xff);
227			outb(TIMER_CNTR0, timer0_max_count >> 8);
228			enable_intr();
229			/*
230			 * See microtime.s for this magic.
231			 */
232#ifdef PC98
233#ifndef AUTO_CLOCK
234#ifndef PC98_8M
235			time.tv_usec += (6667 *
236				(timer0_prescaler_count - hardclock_max_count))
237				>> 14;
238#else /* PC98_8M */
239			time.tv_usec += (16411 *
240				(timer0_prescaler_count - hardclock_max_count))
241				>> 15;
242#endif /* PC98_8M */
243#else /* AUTO_CLOCK */
244			if (pc98_machine_type & M_8M) {
245				/* PC98_8M */
246				time.tv_usec += (16411 *
247					(timer0_prescaler_count -
248					 hardclock_max_count)) >> 15;
249			} else {
250				time.tv_usec += (6667 *
251					(timer0_prescaler_count -
252					 hardclock_max_count)) >> 14;
253			}
254#endif /* AUTO_CLOCK */
255#else /* IBM-PC */
256			time.tv_usec += (27465 *
257				(timer0_prescaler_count - hardclock_max_count))
258				>> 15;
259#endif /* PC98 */
260			if (time.tv_usec >= 1000000)
261				time.tv_usec -= 1000000;
262			timer0_prescaler_count = 0;
263			timer_func = hardclock;
264			timer0_state = RELEASED;
265		}
266		break;
267	}
268}
269
270/*
271 * The acquire and release functions must be called at ipl >= splclock().
272 */
273int
274acquire_timer0(int rate, void (*function) __P((struct clockframe *frame)))
275{
276	static int old_rate;
277
278	if (rate <= 0 || rate > TIMER0_MAX_FREQ)
279		return (-1);
280	switch (timer0_state) {
281
282	case RELEASED:
283		timer0_state = ACQUIRE_PENDING;
284		break;
285
286	case RELEASE_PENDING:
287		if (rate != old_rate)
288			return (-1);
289		/*
290		 * The timer has been released recently, but is being
291		 * re-acquired before the release completed.  In this
292		 * case, we simply reclaim it as if it had not been
293		 * released at all.
294		 */
295		timer0_state = ACQUIRED;
296		break;
297
298	default:
299		return (-1);	/* busy */
300	}
301	new_function = function;
302	old_rate = new_rate = rate;
303	return (0);
304}
305
306#ifdef PC98
307int
308acquire_timer1(int mode)
309{
310
311	if (timer1_state != RELEASED)
312		return (-1);
313	timer1_state = ACQUIRED;
314
315	/*
316	 * This access to the timer registers is as atomic as possible
317	 * because it is a single instruction.  We could do better if we
318	 * knew the rate.  Use of splclock() limits glitches to 10-100us,
319	 * and this is probably good enough for timer2, so we aren't as
320	 * careful with it as with timer0.
321	 */
322	outb(TIMER_MODE, TIMER_SEL1 | (mode & 0x3f));
323
324	return (0);
325}
326#endif
327
328int
329acquire_timer2(int mode)
330{
331
332	if (timer2_state != RELEASED)
333		return (-1);
334	timer2_state = ACQUIRED;
335
336	/*
337	 * This access to the timer registers is as atomic as possible
338	 * because it is a single instruction.  We could do better if we
339	 * knew the rate.  Use of splclock() limits glitches to 10-100us,
340	 * and this is probably good enough for timer2, so we aren't as
341	 * careful with it as with timer0.
342	 */
343	outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f));
344
345	return (0);
346}
347
348int
349release_timer0()
350{
351	switch (timer0_state) {
352
353	case ACQUIRED:
354		timer0_state = RELEASE_PENDING;
355		break;
356
357	case ACQUIRE_PENDING:
358		/* Nothing happened yet, release quickly. */
359		timer0_state = RELEASED;
360		break;
361
362	default:
363		return (-1);
364	}
365	return (0);
366}
367
368#ifdef PC98
369int
370release_timer1()
371{
372
373	if (timer1_state != ACQUIRED)
374		return (-1);
375	timer1_state = RELEASED;
376	outb(TIMER_MODE, TIMER_SEL1 | TIMER_SQWAVE | TIMER_16BIT);
377	return (0);
378}
379#endif
380
381int
382release_timer2()
383{
384
385	if (timer2_state != ACQUIRED)
386		return (-1);
387	timer2_state = RELEASED;
388	outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT);
389	return (0);
390}
391
392#ifndef PC98
393/*
394 * This routine receives statistical clock interrupts from the RTC.
395 * As explained above, these occur at 128 interrupts per second.
396 * When profiling, we receive interrupts at a rate of 1024 Hz.
397 *
398 * This does not actually add as much overhead as it sounds, because
399 * when the statistical clock is active, the hardclock driver no longer
400 * needs to keep (inaccurate) statistics on its own.  This decouples
401 * statistics gathering from scheduling interrupts.
402 *
403 * The RTC chip requires that we read status register C (RTC_INTR)
404 * to acknowledge an interrupt, before it will generate the next one.
405 */
406static void
407rtcintr(struct clockframe frame)
408{
409	u_char stat;
410	stat = rtcin(RTC_INTR);
411	if(stat & RTCIR_PERIOD) {
412		statclock(&frame);
413	}
414}
415
416#include "opt_ddb.h"
417#ifdef DDB
418#include <ddb/ddb.h>
419
420DB_SHOW_COMMAND(rtc, rtc)
421{
422	printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
423	       rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
424	       rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
425	       rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
426}
427#endif /* DDB */
428#endif /* for PC98 */
429
430static int
431getit(void)
432{
433	u_long ef;
434	int high, low;
435
436	ef = read_eflags();
437	disable_intr();
438
439	/* Select timer0 and latch counter value. */
440	outb(TIMER_MODE, TIMER_SEL0);
441
442	low = inb(TIMER_CNTR0);
443	high = inb(TIMER_CNTR0);
444
445	write_eflags(ef);
446	return ((high << 8) | low);
447}
448
449/*
450 * Wait "n" microseconds.
451 * Relies on timer 1 counting down from (timer_freq / hz)
452 * Note: timer had better have been programmed before this is first used!
453 */
454void
455DELAY(int n)
456{
457	int prev_tick, tick, ticks_left, sec, usec;
458
459#ifdef DELAYDEBUG
460	int getit_calls = 1;
461	int n1;
462	static int state = 0;
463
464	if (state == 0) {
465		state = 1;
466		for (n1 = 1; n1 <= 10000000; n1 *= 10)
467			DELAY(n1);
468		state = 2;
469	}
470	if (state == 1)
471		printf("DELAY(%d)...", n);
472#endif
473	/*
474	 * Read the counter first, so that the rest of the setup overhead is
475	 * counted.  Guess the initial overhead is 20 usec (on most systems it
476	 * takes about 1.5 usec for each of the i/o's in getit().  The loop
477	 * takes about 6 usec on a 486/33 and 13 usec on a 386/20.  The
478	 * multiplications and divisions to scale the count take a while).
479	 */
480	prev_tick = getit();
481	n -= 20;
482	/*
483	 * Calculate (n * (timer_freq / 1e6)) without using floating point
484	 * and without any avoidable overflows.
485	 */
486	sec = n / 1000000;
487	usec = n - sec * 1000000;
488	ticks_left = sec * timer_freq
489		     + usec * (timer_freq / 1000000)
490		     + usec * ((timer_freq % 1000000) / 1000) / 1000
491		     + usec * (timer_freq % 1000) / 1000000;
492	if (n < 0)
493		ticks_left = 0;	/* XXX timer_freq is unsigned */
494
495	while (ticks_left > 0) {
496		tick = getit();
497#ifdef DELAYDEBUG
498		++getit_calls;
499#endif
500		if (tick > prev_tick)
501			ticks_left -= prev_tick - (tick - timer0_max_count);
502		else
503			ticks_left -= prev_tick - tick;
504		prev_tick = tick;
505	}
506#ifdef DELAYDEBUG
507	if (state == 1)
508		printf(" %d calls to getit() at %d usec each\n",
509		       getit_calls, (n + 5) / getit_calls);
510#endif
511}
512
513static void
514sysbeepstop(void *chan)
515{
516#ifdef PC98	/* PC98 */
517	outb(IO_PPI, inb(IO_PPI)|0x08);	/* disable counter1 output to speaker */
518	release_timer1();
519#else
520	outb(IO_PPI, inb(IO_PPI)&0xFC);	/* disable counter2 output to speaker */
521	release_timer2();
522#endif
523	beeping = 0;
524}
525
526int
527sysbeep(int pitch, int period)
528{
529	int x = splclock();
530
531#ifdef PC98
532	if (acquire_timer1(TIMER_SQWAVE|TIMER_16BIT))
533		if (!beeping) {
534			/* Something else owns it. */
535			splx(x);
536			return (-1); /* XXX Should be EBUSY, but nobody cares anyway. */
537		}
538	disable_intr();
539	outb(0x3fdb, pitch);
540	outb(0x3fdb, (pitch>>8));
541	enable_intr();
542	if (!beeping) {
543		/* enable counter1 output to speaker */
544		outb(IO_PPI, (inb(IO_PPI) & 0xf7));
545		beeping = period;
546		timeout(sysbeepstop, (void *)NULL, period);
547	}
548#else
549	if (acquire_timer2(TIMER_SQWAVE|TIMER_16BIT))
550		if (!beeping) {
551			/* Something else owns it. */
552			splx(x);
553			return (-1); /* XXX Should be EBUSY, but nobody cares anyway. */
554		}
555	disable_intr();
556	outb(TIMER_CNTR2, pitch);
557	outb(TIMER_CNTR2, (pitch>>8));
558	enable_intr();
559	if (!beeping) {
560		/* enable counter2 output to speaker */
561		outb(IO_PPI, inb(IO_PPI) | 3);
562		beeping = period;
563		timeout(sysbeepstop, (void *)NULL, period);
564	}
565#endif
566	splx(x);
567	return (0);
568}
569
570#ifndef PC98
571/*
572 * RTC support routines
573 */
574
575int
576rtcin(reg)
577	int reg;
578{
579	u_char val;
580
581	outb(IO_RTC, reg);
582	inb(0x84);
583	val = inb(IO_RTC + 1);
584	inb(0x84);
585	return (val);
586}
587
588static __inline void
589writertc(u_char reg, u_char val)
590{
591	outb(IO_RTC, reg);
592	outb(IO_RTC + 1, val);
593}
594
595static __inline int
596readrtc(int port)
597{
598	return(bcd2bin(rtcin(port)));
599}
600#endif
601
602#ifdef PC98
603unsigned int delaycount;
604#define FIRST_GUESS	0x2000
605static void findcpuspeed(void)
606{
607	int i;
608	int remainder;
609
610	/* Put counter in count down mode */
611	outb(TIMER_MODE, TIMER_SEL0 | TIMER_16BIT | TIMER_RATEGEN);
612	outb(TIMER_CNTR0, 0xff);
613	outb(TIMER_CNTR0, 0xff);
614	for (i = FIRST_GUESS; i; i--)
615		;
616	remainder = getit();
617	delaycount = (FIRST_GUESS * TIMER_DIV(1000)) / (0xffff - remainder);
618}
619#endif
620
621#ifndef PC98
622static u_int
623calibrate_clocks(void)
624{
625	u_int count, prev_count, tot_count;
626	int sec, start_sec, timeout;
627
628	printf("Calibrating clock(s) relative to mc146818A clock...\n");
629	if (!(rtcin(RTC_STATUSD) & RTCSD_PWR))
630		goto fail;
631	timeout = 100000000;
632
633	/* Read the mc146818A seconds counter. */
634	for (;;) {
635		if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) {
636			sec = rtcin(RTC_SEC);
637			break;
638		}
639		if (--timeout == 0)
640			goto fail;
641	}
642
643	/* Wait for the mC146818A seconds counter to change. */
644	start_sec = sec;
645	for (;;) {
646		if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) {
647			sec = rtcin(RTC_SEC);
648			if (sec != start_sec)
649				break;
650		}
651		if (--timeout == 0)
652			goto fail;
653	}
654
655	/* Start keeping track of the i8254 counter. */
656	prev_count = getit();
657	if (prev_count == 0 || prev_count > timer0_max_count)
658		goto fail;
659	tot_count = 0;
660
661#if defined(I586_CPU) || defined(I686_CPU)
662	if (cpu_class == CPUCLASS_586 || cpu_class == CPUCLASS_686)
663		wrmsr(0x10, 0LL);	/* XXX 0x10 is the MSR for the TSC */
664#endif
665
666	/*
667	 * Wait for the mc146818A seconds counter to change.  Read the i8254
668	 * counter for each iteration since this is convenient and only
669	 * costs a few usec of inaccuracy. The timing of the final reads
670	 * of the counters almost matches the timing of the initial reads,
671	 * so the main cause of inaccuracy is the varying latency from
672	 * inside getit() or rtcin(RTC_STATUSA) to the beginning of the
673	 * rtcin(RTC_SEC) that returns a changed seconds count.  The
674	 * maximum inaccuracy from this cause is < 10 usec on 486's.
675	 */
676	start_sec = sec;
677	for (;;) {
678		if (!(rtcin(RTC_STATUSA) & RTCSA_TUP))
679			sec = rtcin(RTC_SEC);
680		count = getit();
681		if (count == 0 || count > timer0_max_count)
682			goto fail;
683		if (count > prev_count)
684			tot_count += prev_count - (count - timer0_max_count);
685		else
686			tot_count += prev_count - count;
687		prev_count = count;
688		if (sec != start_sec)
689			break;
690		if (--timeout == 0)
691			goto fail;
692	}
693
694#if defined(I586_CPU) || defined(I686_CPU)
695	/*
696	 * Read the cpu cycle counter.  The timing considerations are
697	 * similar to those for the i8254 clock.
698	 */
699	if (cpu_class == CPUCLASS_586 || cpu_class == CPUCLASS_686) {
700		set_i586_ctr_freq((u_int)rdtsc(), tot_count);
701		printf("i586 clock: %u Hz, ", i586_ctr_freq);
702	}
703#endif
704
705	printf("i8254 clock: %u Hz\n", tot_count);
706	return (tot_count);
707
708fail:
709	printf("failed, using default i8254 clock of %u Hz\n", timer_freq);
710	return (timer_freq);
711}
712#endif	/* !PC98 */
713
714static void
715set_timer_freq(u_int freq, int intr_freq)
716{
717	u_long ef;
718
719	ef = read_eflags();
720	disable_intr();
721	timer_freq = freq;
722	timer0_max_count = hardclock_max_count = TIMER_DIV(intr_freq);
723	timer0_overflow_threshold = timer0_max_count - TIMER0_LATCH_COUNT;
724	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
725	outb(TIMER_CNTR0, timer0_max_count & 0xff);
726	outb(TIMER_CNTR0, timer0_max_count >> 8);
727	write_eflags(ef);
728}
729
730/*
731 * Initialize 8253 timer 0 early so that it can be used in DELAY().
732 * XXX initialization of other timers is unintentionally left blank.
733 */
734void
735startrtclock()
736{
737	u_int delta, freq;
738
739#ifdef PC98
740	findcpuspeed();
741#ifndef AUTO_CLOCK
742	if (pc98_machine_type & M_8M) {
743#ifndef	PC98_8M
744		printf("you must reconfig a kernel with \"PC98_8M\" option.\n");
745#endif
746	} else {
747#ifdef	PC98_8M
748		printf("You must reconfig a kernel without \"PC98_8M\" option.\n");
749#endif
750	}
751#else /* AUTO_CLOCK */
752	if (pc98_machine_type & M_8M)
753		timer_freq = 1996800L; /* 1.9968 MHz */
754	else
755		timer_freq = 2457600L; /* 2.4576 MHz */
756#endif /* AUTO_CLOCK */
757#endif /* PC98 */
758
759#ifndef PC98
760	writertc(RTC_STATUSA, rtc_statusa);
761	writertc(RTC_STATUSB, RTCSB_24HR);
762#endif
763
764#ifndef PC98
765	set_timer_freq(timer_freq, hz);
766	freq = calibrate_clocks();
767#ifdef CLK_CALIBRATION_LOOP
768	if (bootverbose) {
769		printf(
770		"Press a key on the console to abort clock calibration\n");
771		while (cncheckc() == -1)
772			calibrate_clocks();
773	}
774#endif
775
776	/*
777	 * Use the calibrated i8254 frequency if it seems reasonable.
778	 * Otherwise use the default, and don't use the calibrated i586
779	 * frequency.
780	 */
781	delta = freq > timer_freq ? freq - timer_freq : timer_freq - freq;
782	if (delta < timer_freq / 100) {
783#ifndef CLK_USE_I8254_CALIBRATION
784		if (bootverbose)
785		    printf(
786"CLK_USE_I8254_CALIBRATION not specified - using default frequency\n");
787		freq = timer_freq;
788#endif
789		timer_freq = freq;
790	} else {
791		printf("%d Hz differs from default of %d Hz by more than 1%%\n",
792		       freq, timer_freq);
793#if defined(I586_CPU) || defined(I686_CPU)
794		i586_ctr_freq = 0;
795#endif
796	}
797#endif
798
799	set_timer_freq(timer_freq, hz);
800
801#if defined(I586_CPU) || defined(I686_CPU)
802#ifndef CLK_USE_I586_CALIBRATION
803	if (i586_ctr_freq != 0) {
804		if (bootverbose)
805		    printf(
806"CLK_USE_I586_CALIBRATION not specified - using old calibration method\n");
807		i586_ctr_freq = 0;
808	}
809#endif
810	if (i586_ctr_freq == 0 &&
811	    (cpu_class == CPUCLASS_586 || cpu_class == CPUCLASS_686)) {
812		/*
813		 * Calibration of the i586 clock relative to the mc146818A
814		 * clock failed.  Do a less accurate calibration relative
815		 * to the i8254 clock.
816		 */
817		wrmsr(0x10, 0LL);	/* XXX */
818		DELAY(1000000);
819		set_i586_ctr_freq((u_int)rdtsc(), timer_freq);
820#ifdef CLK_USE_I586_CALIBRATION
821		printf("i586 clock: %u Hz\n", i586_ctr_freq);
822#endif
823	}
824#endif
825}
826
827#ifdef PC98
828void
829rtc_serialcombit(int i)
830{
831	outb(IO_RTC, ((i&0x01)<<5)|0x07);
832	DELAY(1);
833	outb(IO_RTC, ((i&0x01)<<5)|0x17);
834	DELAY(1);
835	outb(IO_RTC, ((i&0x01)<<5)|0x07);
836	DELAY(1);
837}
838
839void
840rtc_serialcom(int i)
841{
842	rtc_serialcombit(i&0x01);
843	rtc_serialcombit((i&0x02)>>1);
844	rtc_serialcombit((i&0x04)>>2);
845	rtc_serialcombit((i&0x08)>>3);
846	outb(IO_RTC, 0x07);
847	DELAY(1);
848	outb(IO_RTC, 0x0f);
849	DELAY(1);
850	outb(IO_RTC, 0x07);
851 	DELAY(1);
852}
853
854void
855rtc_outb(int val)
856{
857	int s;
858	int sa = 0;
859
860	for (s=0;s<8;s++) {
861	    sa = ((val >> s) & 0x01) ? 0x27 : 0x07;
862	    outb(IO_RTC, sa);		/* set DI & CLK 0 */
863	    DELAY(1);
864	    outb(IO_RTC, sa | 0x10);	/* CLK 1 */
865	    DELAY(1);
866	}
867	outb(IO_RTC, sa & 0xef);	/* CLK 0 */
868}
869
870int
871rtc_inb(void)
872{
873	int s;
874	int sa = 0;
875
876	for (s=0;s<8;s++) {
877	    sa |= ((inb(0x33) & 0x01) << s);
878	    outb(IO_RTC, 0x17);	/* CLK 1 */
879	    DELAY(1);
880	    outb(IO_RTC, 0x07);	/* CLK 0 */
881	    DELAY(2);
882	}
883	return sa;
884}
885#endif /* PC-98 */
886
887/*
888 * Initialize the time of day register,	based on the time base which is, e.g.
889 * from	a filesystem.
890 */
891void
892inittodr(time_t base)
893{
894	unsigned long	sec, days;
895	int		yd;
896	int		year, month;
897	int		y, m, s;
898#ifdef PC98
899	int		second, min, hour;
900#endif
901
902	s = splclock();
903	time.tv_sec  = base;
904	time.tv_usec = 0;
905	splx(s);
906
907#ifdef PC98
908	rtc_serialcom(0x03);	/* Time Read */
909	rtc_serialcom(0x01);	/* Register shift command. */
910	DELAY(20);
911
912	second = bcd2bin(rtc_inb() & 0xff);	/* sec */
913	min = bcd2bin(rtc_inb() & 0xff);	/* min */
914	hour = bcd2bin(rtc_inb() & 0xff);	/* hour */
915	days = bcd2bin(rtc_inb() & 0xff) - 1;	/* date */
916
917	month = (rtc_inb() >> 4) & 0x0f;	/* month */
918	for (m = 1; m <	month; m++)
919		days +=	daysinmonth[m-1];
920	year = bcd2bin(rtc_inb() & 0xff) + 1900;	/* year */
921	/* 2000 year problem */
922	if (year < 1995)
923		year += 100;
924	if (year < 1970)
925		goto wrong_time;
926	for (y = 1970; y < year; y++)
927		days +=	DAYSPERYEAR + LEAPYEAR(y);
928	if ((month > 2)	&& LEAPYEAR(year))
929		days ++;
930	sec = ((( days * 24 +
931		  hour) * 60 +
932		  min) * 60 +
933		  second);
934	/* sec now contains the	number of seconds, since Jan 1 1970,
935	   in the local	time zone */
936#else	/* IBM-PC */
937	/* Look	if we have a RTC present and the time is valid */
938	if (!(rtcin(RTC_STATUSD) & RTCSD_PWR))
939		goto wrong_time;
940
941	/* wait	for time update	to complete */
942	/* If RTCSA_TUP	is zero, we have at least 244us	before next update */
943	while (rtcin(RTC_STATUSA) & RTCSA_TUP);
944
945	days = 0;
946#ifdef USE_RTC_CENTURY
947	year = readrtc(RTC_YEAR) + readrtc(RTC_CENTURY)	* 100;
948#else
949	year = readrtc(RTC_YEAR) + 1900;
950	if (year < 1970)
951		year += 100;
952#endif
953	if (year < 1970)
954		goto wrong_time;
955	month =	readrtc(RTC_MONTH);
956	for (m = 1; m <	month; m++)
957		days +=	daysinmonth[m-1];
958	if ((month > 2)	&& LEAPYEAR(year))
959		days ++;
960	days +=	readrtc(RTC_DAY) - 1;
961	yd = days;
962	for (y = 1970; y < year; y++)
963		days +=	DAYSPERYEAR + LEAPYEAR(y);
964	sec = ((( days * 24 +
965		  readrtc(RTC_HRS)) * 60 +
966		  readrtc(RTC_MIN)) * 60 +
967		  readrtc(RTC_SEC));
968	/* sec now contains the	number of seconds, since Jan 1 1970,
969	   in the local	time zone */
970#endif
971
972	sec += tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
973
974	s = splclock();
975	time.tv_sec = sec;
976	splx(s);
977	return;
978
979wrong_time:
980	printf("Invalid	time in	real time clock.\n");
981	printf("Check and reset	the date immediately!\n");
982}
983
984/*
985 * Write system	time back to RTC
986 */
987void
988resettodr()
989{
990	unsigned long	tm;
991	int		y, m, s;
992#ifdef PC98
993	int		wd;
994#endif
995
996	if (disable_rtc_set)
997		return;
998
999	s = splclock();
1000	tm = time.tv_sec;
1001	splx(s);
1002
1003#ifdef PC98
1004	rtc_serialcom(0x01);	/* Register shift command. */
1005
1006	/* Calculate local time	to put in RTC */
1007
1008	tm -= tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
1009
1010	rtc_outb(bin2bcd(tm%60)); tm /= 60;	/* Write back Seconds */
1011	rtc_outb(bin2bcd(tm%60)); tm /= 60;	/* Write back Minutes */
1012	rtc_outb(bin2bcd(tm%24)); tm /= 24;	/* Write back Hours   */
1013
1014	/* We have now the days	since 01-01-1970 in tm */
1015	wd = (tm+4)%7;
1016	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
1017	     tm >= m;
1018	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
1019	     tm -= m;
1020
1021	/* Now we have the years in y and the day-of-the-year in tm */
1022	for (m = 0; ; m++) {
1023		int ml;
1024
1025		ml = daysinmonth[m];
1026		if (m == 1 && LEAPYEAR(y))
1027			ml++;
1028		if (tm < ml)
1029			break;
1030		tm -= ml;
1031	}
1032
1033	m++;
1034	rtc_outb(bin2bcd(tm+1));		/* Write back Day     */
1035	rtc_outb((m << 4) | wd);		/* Write back Month & Weekday  */
1036	rtc_outb(bin2bcd(y%100));		/* Write back Year    */
1037
1038	rtc_serialcom(0x02);	/* Time set & Counter hold command. */
1039	rtc_serialcom(0x00);	/* Register hold command. */
1040#else
1041	/* Disable RTC updates and interrupts. */
1042	writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
1043
1044	/* Calculate local time	to put in RTC */
1045
1046	tm -= tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
1047
1048	writertc(RTC_SEC, bin2bcd(tm%60)); tm /= 60;	/* Write back Seconds */
1049	writertc(RTC_MIN, bin2bcd(tm%60)); tm /= 60;	/* Write back Minutes */
1050	writertc(RTC_HRS, bin2bcd(tm%24)); tm /= 24;	/* Write back Hours   */
1051
1052	/* We have now the days	since 01-01-1970 in tm */
1053	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
1054	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
1055	     tm >= m;
1056	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
1057	     tm -= m;
1058
1059	/* Now we have the years in y and the day-of-the-year in tm */
1060	writertc(RTC_YEAR, bin2bcd(y%100));		/* Write back Year    */
1061#ifdef USE_RTC_CENTURY
1062	writertc(RTC_CENTURY, bin2bcd(y/100));		/* ... and Century    */
1063#endif
1064	for (m = 0; ; m++) {
1065		int ml;
1066
1067		ml = daysinmonth[m];
1068		if (m == 1 && LEAPYEAR(y))
1069			ml++;
1070		if (tm < ml)
1071			break;
1072		tm -= ml;
1073	}
1074
1075	writertc(RTC_MONTH, bin2bcd(m + 1));            /* Write back Month   */
1076	writertc(RTC_DAY, bin2bcd(tm + 1));             /* Write back Month Day */
1077
1078	/* Reenable RTC updates and interrupts. */
1079	writertc(RTC_STATUSB, rtc_statusb);
1080#endif
1081}
1082
1083/*
1084 * Start both clocks running.
1085 */
1086void
1087cpu_initclocks()
1088{
1089#ifndef PC98
1090	int diag;
1091
1092	if (statclock_disable) {
1093		/*
1094		 * The stat interrupt mask is different without the
1095		 * statistics clock.  Also, don't set the interrupt
1096		 * flag which would normally cause the RTC to generate
1097		 * interrupts.
1098		 */
1099		stat_imask = HWI_MASK | SWI_MASK;
1100		rtc_statusb = RTCSB_24HR;
1101	} else {
1102	        /* Setting stathz to nonzero early helps avoid races. */
1103		stathz = RTC_NOPROFRATE;
1104		profhz = RTC_PROFRATE;
1105        }
1106#endif
1107
1108	/* Finish initializing 8253 timer 0. */
1109	register_intr(/* irq */ 0, /* XXX id */ 0, /* flags */ 0,
1110		      /* XXX */ (inthand2_t *)clkintr, &clk_imask,
1111		      /* unit */ 0);
1112	INTREN(IRQ0);
1113#if defined(I586_CPU) || defined(I686_CPU)
1114	/*
1115	 * Finish setting up anti-jitter measures.
1116	 */
1117	if (i586_ctr_freq != 0) {
1118		i586_last_tick = rdtsc();
1119		i586_ctr_bias = i586_last_tick;
1120	}
1121#endif
1122
1123#ifndef PC98
1124	/* Initialize RTC. */
1125	writertc(RTC_STATUSA, rtc_statusa);
1126	writertc(RTC_STATUSB, RTCSB_24HR);
1127
1128	/* Don't bother enabling the statistics clock. */
1129	if (statclock_disable)
1130		return;
1131	diag = rtcin(RTC_DIAG);
1132	if (diag != 0)
1133		printf("RTC BIOS diagnostic error %b\n", diag, RTCDG_BITS);
1134	register_intr(/* irq */ 8, /* XXX id */ 1, /* flags */ 0,
1135		      /* XXX */ (inthand2_t *)rtcintr, &stat_imask,
1136		      /* unit */ 0);
1137	INTREN(IRQ8);
1138	writertc(RTC_STATUSB, rtc_statusb);
1139#endif
1140}
1141
1142void
1143setstatclockrate(int newhz)
1144{
1145#ifndef PC98
1146	if (newhz == RTC_PROFRATE)
1147		rtc_statusa = RTCSA_DIVIDER | RTCSA_PROF;
1148	else
1149		rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
1150	writertc(RTC_STATUSA, rtc_statusa);
1151#endif
1152}
1153
1154static int
1155sysctl_machdep_i8254_freq SYSCTL_HANDLER_ARGS
1156{
1157	int error;
1158	u_int freq;
1159
1160	/*
1161	 * Use `i8254' instead of `timer' in external names because `timer'
1162	 * is is too generic.  Should use it everywhere.
1163	 */
1164	freq = timer_freq;
1165	error = sysctl_handle_opaque(oidp, &freq, sizeof freq, req);
1166	if (error == 0 && req->newptr != NULL) {
1167		if (timer0_state != 0)
1168			return (EBUSY);	/* too much trouble to handle */
1169		set_timer_freq(freq, hz);
1170#if defined(I586_CPU) || defined(I686_CPU)
1171		set_i586_ctr_freq(i586_ctr_freq, timer_freq);
1172#endif
1173	}
1174	return (error);
1175}
1176
1177SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
1178	    0, sizeof(u_int), sysctl_machdep_i8254_freq, "I", "");
1179
1180#if defined(I586_CPU) || defined(I686_CPU)
1181static void
1182set_i586_ctr_freq(u_int i586_freq, u_int i8254_freq)
1183{
1184	u_int comultiplier, multiplier;
1185	u_long ef;
1186
1187	if (i586_freq == 0) {
1188		i586_ctr_freq = i586_freq;
1189		return;
1190	}
1191	comultiplier = ((unsigned long long)i586_freq
1192			<< I586_CTR_COMULTIPLIER_SHIFT) / i8254_freq;
1193	multiplier = (1000000LL << I586_CTR_MULTIPLIER_SHIFT) / i586_freq;
1194	ef = read_eflags();
1195	disable_intr();
1196	i586_ctr_freq = i586_freq;
1197	i586_ctr_comultiplier = comultiplier;
1198	i586_ctr_multiplier = multiplier;
1199	write_eflags(ef);
1200}
1201
1202static int
1203sysctl_machdep_i586_freq SYSCTL_HANDLER_ARGS
1204{
1205	int error;
1206	u_int freq;
1207
1208	if (cpu_class != CPUCLASS_586 && cpu_class != CPUCLASS_686)
1209		return (EOPNOTSUPP);
1210	freq = i586_ctr_freq;
1211	error = sysctl_handle_opaque(oidp, &freq, sizeof freq, req);
1212	if (error == 0 && req->newptr != NULL)
1213		set_i586_ctr_freq(freq, timer_freq);
1214	return (error);
1215}
1216
1217SYSCTL_PROC(_machdep, OID_AUTO, i586_freq, CTLTYPE_INT | CTLFLAG_RW,
1218	    0, sizeof(u_int), sysctl_machdep_i586_freq, "I", "");
1219#endif /* defined(I586_CPU) || defined(I686_CPU) */
1220