2 * Copyright (c) 1990 The Regents of the University of California.
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz and Don Ahn.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
36 * from: @(#)clock.c 7.2 (Berkeley) 5/12/91
41 * Routines to handle clock hardware.
45 * inittodr, settodr and support routines written
46 * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>
48 * reintroduced and updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
51 #include "opt_clock.h"
54 #include <sys/param.h>
55 #include <sys/systm.h>
57 #include <sys/kernel.h>
61 #include <sys/sysctl.h>
64 #include <machine/clock.h>
65 #ifdef CLK_CALIBRATION_LOOP
67 #include <machine/cputypes.h>
68 #include <machine/frame.h>
69 #include <machine/ipl.h>
70 #include <machine/limits.h>
71 #include <machine/md_var.h>
72 #include <machine/psl.h>
74 #include <machine/segments.h>
76 #if defined(SMP) || defined(APIC_IO)
77 #include <machine/smp.h>
78 #endif /* SMP || APIC_IO */
79 #include <machine/specialreg.h>
81 #include <i386/isa/icu.h>
82 #include <i386/isa/isa.h>
84 #include <i386/isa/timerreg.h>
86 #include <i386/isa/intr_machdep.h>
90 #include <i386/isa/mca_machdep.h>
94 #define disable_intr() CLOCK_DISABLE_INTR()
95 #define enable_intr() CLOCK_ENABLE_INTR()
98 #include <i386/isa/intr_machdep.h>
99 /* The interrupt triggered by the 8254 (timer) chip */
101 static u_long read_intr_count __P((int vec));
102 static void setup_8254_mixed_mode __P((void));
107 * 32-bit time_t's can't reach leap years before 1904 or after 2036, so we
108 * can use a simple formula for leap years.
110 #define LEAPYEAR(y) ((u_int)(y) % 4 == 0)
111 #define DAYSPERYEAR (31+28+31+30+31+30+31+31+30+31+30+31)
113 #define TIMER_DIV(x) ((timer_freq + (x) / 2) / (x))
116 * Time in timer cycles that it takes for microtime() to disable interrupts
117 * and latch the count. microtime() currently uses "cli; outb ..." so it
118 * normally takes less than 2 timer cycles. Add a few for cache misses.
119 * Add a few more to allow for latency in bogus calls to microtime() with
120 * interrupts already disabled.
122 #define TIMER0_LATCH_COUNT 20
125 * Maximum frequency that we are willing to allow for timer0. Must be
126 * low enough to guarantee that the timer interrupt handler returns
127 * before the next timer interrupt.
129 #define TIMER0_MAX_FREQ 20000
131 int adjkerntz; /* local offset from GMT in seconds */
133 int disable_rtc_set; /* disable resettodr() if != 0 */
134 volatile u_int idelayed;
135 int statclock_disable;
136 u_int stat_imask = SWI_CLOCK_MASK;
138 #define TIMER_FREQ 1193182
140 u_int timer_freq = TIMER_FREQ;
141 int timer0_max_count;
144 int wall_cmos_clock; /* wall CMOS clock assumed if != 0 */
146 static int beeping = 0;
147 static u_int clk_imask = HWI_MASK | SWI_MASK;
148 static const u_char daysinmonth[] = {31,28,31,30,31,30,31,31,30,31,30,31};
149 static u_int hardclock_max_count;
150 static u_int32_t i8254_lastcount;
151 static u_int32_t i8254_offset;
152 static int i8254_ticked;
154 * XXX new_function and timer_func should not handle clockframes, but
155 * timer_func currently needs to hold hardclock to handle the
156 * timer0_state == 0 case. We should use register_intr()/unregister_intr()
157 * to switch between clkintr() and a slightly different timerintr().
159 static void (*new_function) __P((struct clockframe *frame));
160 static u_int new_rate;
161 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
162 static u_char rtc_statusb = RTCSB_24HR | RTCSB_PINTR;
163 static u_int timer0_prescaler_count;
165 /* Values for timerX_state: */
167 #define RELEASE_PENDING 1
169 #define ACQUIRE_PENDING 3
171 static u_char timer0_state;
172 static u_char timer2_state;
173 static void (*timer_func) __P((struct clockframe *frame)) = hardclock;
174 static u_int tsc_present;
176 static unsigned i8254_get_timecount __P((struct timecounter *tc));
177 static unsigned tsc_get_timecount __P((struct timecounter *tc));
178 static void set_timer_freq(u_int freq, int intr_freq);
180 static struct timecounter tsc_timecounter = {
181 tsc_get_timecount, /* get_timecount */
183 ~0u, /* counter_mask */
188 SYSCTL_OPAQUE(_debug, OID_AUTO, tsc_timecounter, CTLFLAG_RD,
189 &tsc_timecounter, sizeof(tsc_timecounter), "S,timecounter", "");
191 static struct timecounter i8254_timecounter = {
192 i8254_get_timecount, /* get_timecount */
194 ~0u, /* counter_mask */
199 SYSCTL_OPAQUE(_debug, OID_AUTO, i8254_timecounter, CTLFLAG_RD,
200 &i8254_timecounter, sizeof(i8254_timecounter), "S,timecounter", "");
203 clkintr(struct clockframe frame)
205 if (timecounter->tc_get_timecount == i8254_get_timecount) {
210 i8254_offset += timer0_max_count;
217 switch (timer0_state) {
224 if ((timer0_prescaler_count += timer0_max_count)
225 >= hardclock_max_count) {
226 timer0_prescaler_count -= hardclock_max_count;
232 case ACQUIRE_PENDING:
234 i8254_offset = i8254_get_timecount(NULL);
236 timer0_max_count = TIMER_DIV(new_rate);
237 outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
238 outb(TIMER_CNTR0, timer0_max_count & 0xff);
239 outb(TIMER_CNTR0, timer0_max_count >> 8);
241 timer_func = new_function;
242 timer0_state = ACQUIRED;
246 case RELEASE_PENDING:
247 if ((timer0_prescaler_count += timer0_max_count)
248 >= hardclock_max_count) {
250 i8254_offset = i8254_get_timecount(NULL);
252 timer0_max_count = hardclock_max_count;
254 TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
255 outb(TIMER_CNTR0, timer0_max_count & 0xff);
256 outb(TIMER_CNTR0, timer0_max_count >> 8);
258 timer0_prescaler_count = 0;
259 timer_func = hardclock;
260 timer0_state = RELEASED;
267 /* Reset clock interrupt by asserting bit 7 of port 0x61 */
269 outb(0x61, inb(0x61) | 0x80);
274 * The acquire and release functions must be called at ipl >= splclock().
277 acquire_timer0(int rate, void (*function) __P((struct clockframe *frame)))
281 if (rate <= 0 || rate > TIMER0_MAX_FREQ)
283 switch (timer0_state) {
286 timer0_state = ACQUIRE_PENDING;
289 case RELEASE_PENDING:
290 if (rate != old_rate)
293 * The timer has been released recently, but is being
294 * re-acquired before the release completed. In this
295 * case, we simply reclaim it as if it had not been
298 timer0_state = ACQUIRED;
302 return (-1); /* busy */
304 new_function = function;
305 old_rate = new_rate = rate;
310 acquire_timer2(int mode)
313 if (timer2_state != RELEASED)
315 timer2_state = ACQUIRED;
318 * This access to the timer registers is as atomic as possible
319 * because it is a single instruction. We could do better if we
320 * knew the rate. Use of splclock() limits glitches to 10-100us,
321 * and this is probably good enough for timer2, so we aren't as
322 * careful with it as with timer0.
324 outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f));
332 switch (timer0_state) {
335 timer0_state = RELEASE_PENDING;
338 case ACQUIRE_PENDING:
339 /* Nothing happened yet, release quickly. */
340 timer0_state = RELEASED;
353 if (timer2_state != ACQUIRED)
355 timer2_state = RELEASED;
356 outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT);
361 * This routine receives statistical clock interrupts from the RTC.
362 * As explained above, these occur at 128 interrupts per second.
363 * When profiling, we receive interrupts at a rate of 1024 Hz.
365 * This does not actually add as much overhead as it sounds, because
366 * when the statistical clock is active, the hardclock driver no longer
367 * needs to keep (inaccurate) statistics on its own. This decouples
368 * statistics gathering from scheduling interrupts.
370 * The RTC chip requires that we read status register C (RTC_INTR)
371 * to acknowledge an interrupt, before it will generate the next one.
372 * Under high interrupt load, rtcintr() can be indefinitely delayed and
373 * the clock can tick immediately after the read from RTC_INTR. In this
374 * case, the mc146818A interrupt signal will not drop for long enough
375 * to register with the 8259 PIC. If an interrupt is missed, the stat
376 * clock will halt, considerably degrading system performance. This is
377 * why we use 'while' rather than a more straightforward 'if' below.
378 * Stat clock ticks can still be lost, causing minor loss of accuracy
379 * in the statistics, but the stat clock will no longer stop.
382 rtcintr(struct clockframe frame)
384 while (rtcin(RTC_INTR) & RTCIR_PERIOD)
392 DB_SHOW_COMMAND(rtc, rtc)
394 printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
395 rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
396 rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
397 rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
410 /* Select timer0 and latch counter value. */
411 outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
413 low = inb(TIMER_CNTR0);
414 high = inb(TIMER_CNTR0);
418 return ((high << 8) | low);
422 * Wait "n" microseconds.
423 * Relies on timer 1 counting down from (timer_freq / hz)
424 * Note: timer had better have been programmed before this is first used!
429 int delta, prev_tick, tick, ticks_left;
434 static int state = 0;
438 for (n1 = 1; n1 <= 10000000; n1 *= 10)
443 printf("DELAY(%d)...", n);
446 * Guard against the timer being uninitialized if we are called
447 * early for console i/o.
449 if (timer0_max_count == 0)
450 set_timer_freq(timer_freq, hz);
453 * Read the counter first, so that the rest of the setup overhead is
454 * counted. Guess the initial overhead is 20 usec (on most systems it
455 * takes about 1.5 usec for each of the i/o's in getit(). The loop
456 * takes about 6 usec on a 486/33 and 13 usec on a 386/20. The
457 * multiplications and divisions to scale the count take a while).
460 n -= 0; /* XXX actually guess no initial overhead */
462 * Calculate (n * (timer_freq / 1e6)) without using floating point
463 * and without any avoidable overflows.
469 * Use fixed point to avoid a slow division by 1000000.
470 * 39099 = 1193182 * 2^15 / 10^6 rounded to nearest.
471 * 2^15 is the first power of 2 that gives exact results
472 * for n between 0 and 256.
474 ticks_left = ((u_int)n * 39099 + (1 << 15) - 1) >> 15;
477 * Don't bother using fixed point, although gcc-2.7.2
478 * generates particularly poor code for the long long
479 * division, since even the slow way will complete long
480 * before the delay is up (unless we're interrupted).
482 ticks_left = ((u_int)n * (long long)timer_freq + 999999)
485 while (ticks_left > 0) {
490 delta = prev_tick - tick;
493 delta += timer0_max_count;
495 * Guard against timer0_max_count being wrong.
496 * This shouldn't happen in normal operation,
497 * but it may happen if set_timer_freq() is
507 printf(" %d calls to getit() at %d usec each\n",
508 getit_calls, (n + 5) / getit_calls);
513 sysbeepstop(void *chan)
515 outb(IO_PPI, inb(IO_PPI)&0xFC); /* disable counter2 output to speaker */
521 sysbeep(int pitch, int period)
525 if (acquire_timer2(TIMER_SQWAVE|TIMER_16BIT))
527 /* Something else owns it. */
529 return (-1); /* XXX Should be EBUSY, but nobody cares anyway. */
532 outb(TIMER_CNTR2, pitch);
533 outb(TIMER_CNTR2, (pitch>>8));
536 /* enable counter2 output to speaker */
537 outb(IO_PPI, inb(IO_PPI) | 3);
539 timeout(sysbeepstop, (void *)NULL, period);
546 * RTC support routines
557 val = inb(IO_RTC + 1);
563 writertc(u_char reg, u_char val)
568 outb(IO_RTC + 1, val);
569 inb(0x84); /* XXX work around wrong order in rtcin() */
575 return(bcd2bin(rtcin(port)));
579 calibrate_clocks(void)
582 u_int count, prev_count, tot_count;
583 int sec, start_sec, timeout;
586 printf("Calibrating clock(s) ... ");
587 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR))
591 /* Read the mc146818A seconds counter. */
593 if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) {
594 sec = rtcin(RTC_SEC);
601 /* Wait for the mC146818A seconds counter to change. */
604 if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) {
605 sec = rtcin(RTC_SEC);
606 if (sec != start_sec)
613 /* Start keeping track of the i8254 counter. */
614 prev_count = getit();
615 if (prev_count == 0 || prev_count > timer0_max_count)
622 old_tsc = 0; /* shut up gcc */
625 * Wait for the mc146818A seconds counter to change. Read the i8254
626 * counter for each iteration since this is convenient and only
627 * costs a few usec of inaccuracy. The timing of the final reads
628 * of the counters almost matches the timing of the initial reads,
629 * so the main cause of inaccuracy is the varying latency from
630 * inside getit() or rtcin(RTC_STATUSA) to the beginning of the
631 * rtcin(RTC_SEC) that returns a changed seconds count. The
632 * maximum inaccuracy from this cause is < 10 usec on 486's.
636 if (!(rtcin(RTC_STATUSA) & RTCSA_TUP))
637 sec = rtcin(RTC_SEC);
639 if (count == 0 || count > timer0_max_count)
641 if (count > prev_count)
642 tot_count += prev_count - (count - timer0_max_count);
644 tot_count += prev_count - count;
646 if (sec != start_sec)
653 * Read the cpu cycle counter. The timing considerations are
654 * similar to those for the i8254 clock.
657 tsc_freq = rdtsc() - old_tsc;
661 printf("TSC clock: %u Hz, ", tsc_freq);
662 printf("i8254 clock: %u Hz\n", tot_count);
668 printf("failed, using default i8254 clock of %u Hz\n",
674 set_timer_freq(u_int freq, int intr_freq)
677 int new_timer0_max_count;
682 new_timer0_max_count = hardclock_max_count = TIMER_DIV(intr_freq);
683 if (new_timer0_max_count != timer0_max_count) {
684 timer0_max_count = new_timer0_max_count;
685 outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
686 outb(TIMER_CNTR0, timer0_max_count & 0xff);
687 outb(TIMER_CNTR0, timer0_max_count >> 8);
694 * i8254_restore is called from apm_default_resume() to reload
695 * the countdown register.
696 * this should not be necessary but there are broken laptops that
697 * do not restore the countdown register on resume.
698 * when it happnes, it messes up the hardclock interval and system clock,
699 * which leads to the infamous "calcru: negative time" problem.
708 outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
709 outb(TIMER_CNTR0, timer0_max_count & 0xff);
710 outb(TIMER_CNTR0, timer0_max_count >> 8);
716 * Initialize 8254 timer 0 early so that it can be used in DELAY().
717 * XXX initialization of other timers is unintentionally left blank.
724 if (cpu_feature & CPUID_TSC)
729 writertc(RTC_STATUSA, rtc_statusa);
730 writertc(RTC_STATUSB, RTCSB_24HR);
732 set_timer_freq(timer_freq, hz);
733 freq = calibrate_clocks();
734 #ifdef CLK_CALIBRATION_LOOP
737 "Press a key on the console to abort clock calibration\n");
738 while (cncheckc() == -1)
744 * Use the calibrated i8254 frequency if it seems reasonable.
745 * Otherwise use the default, and don't use the calibrated i586
748 delta = freq > timer_freq ? freq - timer_freq : timer_freq - freq;
749 if (delta < timer_freq / 100) {
750 #ifndef CLK_USE_I8254_CALIBRATION
753 "CLK_USE_I8254_CALIBRATION not specified - using default frequency\n");
760 "%d Hz differs from default of %d Hz by more than 1%%\n",
765 set_timer_freq(timer_freq, hz);
766 i8254_timecounter.tc_frequency = timer_freq;
767 init_timecounter(&i8254_timecounter);
769 #ifndef CLK_USE_TSC_CALIBRATION
773 "CLK_USE_TSC_CALIBRATION not specified - using old calibration method\n");
777 if (tsc_present && tsc_freq == 0) {
779 * Calibration of the i586 clock relative to the mc146818A
780 * clock failed. Do a less accurate calibration relative
781 * to the i8254 clock.
783 u_int64_t old_tsc = rdtsc();
786 tsc_freq = rdtsc() - old_tsc;
787 #ifdef CLK_USE_TSC_CALIBRATION
789 printf("TSC clock: %u Hz (Method B)\n", tsc_freq);
795 * We can not use the TSC in SMP mode, until we figure out a
796 * cheap (impossible), reliable and precise (yeah right!) way
797 * to synchronize the TSCs of all the CPUs.
798 * Curse Intel for leaving the counter out of the I/O APIC.
803 * We can not use the TSC if we support APM. Precise timekeeping
804 * on an APM'ed machine is at best a fools pursuit, since
805 * any and all of the time spent in various SMM code can't
806 * be reliably accounted for. Reading the RTC is your only
807 * source of reliable time info. The i8254 looses too of course
808 * but we need to have some kind of time...
809 * We don't know at this point whether APM is going to be used
810 * or not, nor when it might be activated. Play it safe.
813 #endif /* NAPM > 0 */
815 if (tsc_present && tsc_freq != 0 && !tsc_is_broken) {
816 tsc_timecounter.tc_frequency = tsc_freq;
817 init_timecounter(&tsc_timecounter);
820 #endif /* !defined(SMP) */
824 * Initialize the time of day register, based on the time base which is, e.g.
828 inittodr(time_t base)
830 unsigned long sec, days;
840 set_timecounter(&ts);
844 /* Look if we have a RTC present and the time is valid */
845 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR))
848 /* wait for time update to complete */
849 /* If RTCSA_TUP is zero, we have at least 244us before next update */
850 while (rtcin(RTC_STATUSA) & RTCSA_TUP);
853 #ifdef USE_RTC_CENTURY
854 year = readrtc(RTC_YEAR) + readrtc(RTC_CENTURY) * 100;
856 year = readrtc(RTC_YEAR) + 1900;
862 month = readrtc(RTC_MONTH);
863 for (m = 1; m < month; m++)
864 days += daysinmonth[m-1];
865 if ((month > 2) && LEAPYEAR(year))
867 days += readrtc(RTC_DAY) - 1;
869 for (y = 1970; y < year; y++)
870 days += DAYSPERYEAR + LEAPYEAR(y);
871 sec = ((( days * 24 +
872 readrtc(RTC_HRS)) * 60 +
873 readrtc(RTC_MIN)) * 60 +
875 /* sec now contains the number of seconds, since Jan 1 1970,
876 in the local time zone */
878 sec += tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
880 y = time_second - sec;
881 if (y <= -2 || y >= 2) {
882 /* badly off, adjust it */
886 set_timecounter(&ts);
892 printf("Invalid time in real time clock.\n");
893 printf("Check and reset the date immediately!\n");
897 * Write system time back to RTC
912 /* Disable RTC updates and interrupts. */
913 writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
915 /* Calculate local time to put in RTC */
917 tm -= tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
919 writertc(RTC_SEC, bin2bcd(tm%60)); tm /= 60; /* Write back Seconds */
920 writertc(RTC_MIN, bin2bcd(tm%60)); tm /= 60; /* Write back Minutes */
921 writertc(RTC_HRS, bin2bcd(tm%24)); tm /= 24; /* Write back Hours */
923 /* We have now the days since 01-01-1970 in tm */
924 writertc(RTC_WDAY, (tm+4)%7); /* Write back Weekday */
925 for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
927 y++, m = DAYSPERYEAR + LEAPYEAR(y))
930 /* Now we have the years in y and the day-of-the-year in tm */
931 writertc(RTC_YEAR, bin2bcd(y%100)); /* Write back Year */
932 #ifdef USE_RTC_CENTURY
933 writertc(RTC_CENTURY, bin2bcd(y/100)); /* ... and Century */
939 if (m == 1 && LEAPYEAR(y))
946 writertc(RTC_MONTH, bin2bcd(m + 1)); /* Write back Month */
947 writertc(RTC_DAY, bin2bcd(tm + 1)); /* Write back Month Day */
949 /* Reenable RTC updates and interrupts. */
950 writertc(RTC_STATUSB, rtc_statusb);
955 * Start both clocks running.
963 struct intrec *clkdesc;
966 if (statclock_disable) {
968 * The stat interrupt mask is different without the
969 * statistics clock. Also, don't set the interrupt
970 * flag which would normally cause the RTC to generate
973 stat_imask = HWI_MASK | SWI_MASK;
974 rtc_statusb = RTCSB_24HR;
976 /* Setting stathz to nonzero early helps avoid races. */
977 stathz = RTC_NOPROFRATE;
978 profhz = RTC_PROFRATE;
981 /* Finish initializing 8253 timer 0. */
984 apic_8254_intr = isa_apic_irq(0);
986 if (apic_8254_intr >= 0 ) {
987 if (apic_int_type(0, 0) == 3)
990 /* look for ExtInt on pin 0 */
991 if (apic_int_type(0, 0) == 3) {
993 setup_8254_mixed_mode();
995 panic("APIC_IO: Cannot route 8254 interrupt to CPU");
998 clkdesc = inthand_add("clk", apic_8254_intr, (inthand2_t *)clkintr,
999 NULL, &clk_imask, INTR_EXCL);
1000 INTREN(1 << apic_8254_intr);
1004 inthand_add("clk", 0, (inthand2_t *)clkintr, NULL, &clk_imask,
1008 #endif /* APIC_IO */
1010 /* Initialize RTC. */
1011 writertc(RTC_STATUSA, rtc_statusa);
1012 writertc(RTC_STATUSB, RTCSB_24HR);
1014 /* Don't bother enabling the statistics clock. */
1015 if (statclock_disable)
1017 diag = rtcin(RTC_DIAG);
1019 printf("RTC BIOS diagnostic error %b\n", diag, RTCDG_BITS);
1022 if (isa_apic_irq(8) != 8)
1023 panic("APIC RTC != 8");
1024 #endif /* APIC_IO */
1026 inthand_add("rtc", 8, (inthand2_t *)rtcintr, NULL, &stat_imask,
1033 #endif /* APIC_IO */
1035 writertc(RTC_STATUSB, rtc_statusb);
1038 if (apic_8254_trial) {
1040 printf("APIC_IO: Testing 8254 interrupt delivery\n");
1041 while (read_intr_count(8) < 6)
1043 if (read_intr_count(apic_8254_intr) < 3) {
1045 * The MP table is broken.
1046 * The 8254 was not connected to the specified pin
1048 * Workaround: Limited variant of mixed mode.
1050 INTRDIS(1 << apic_8254_intr);
1051 inthand_remove(clkdesc);
1052 printf("APIC_IO: Broken MP table detected: "
1053 "8254 is not connected to IO APIC int pin %d\n",
1057 setup_8254_mixed_mode();
1058 inthand_add("clk", apic_8254_intr,(inthand2_t *)clkintr,
1059 NULL, &clk_imask, INTR_EXCL);
1060 INTREN(1 << apic_8254_intr);
1065 printf("APIC_IO: routing 8254 via pin %d\n",apic_8254_intr);
1067 printf("APIC_IO: routing 8254 via 8259 on pin 0\n");
1074 read_intr_count(int vec)
1077 up = intr_countp[vec];
1084 setup_8254_mixed_mode()
1087 * Allow 8254 timer to INTerrupt 8259:
1088 * re-initialize master 8259:
1089 * reset; prog 4 bytes, single ICU, edge triggered
1091 outb(IO_ICU1, 0x13);
1092 outb(IO_ICU1 + 1, NRSVIDT); /* start vector (unused) */
1093 outb(IO_ICU1 + 1, 0x00); /* ignore slave */
1094 outb(IO_ICU1 + 1, 0x03); /* auto EOI, 8086 */
1095 outb(IO_ICU1 + 1, 0xfe); /* unmask INT0 */
1097 /* program IO APIC for type 3 INT on INT0 */
1098 if (ext_int_setup(0, 0) < 0)
1099 panic("8254 redirect via APIC pin0 impossible!");
1104 setstatclockrate(int newhz)
1106 if (newhz == RTC_PROFRATE)
1107 rtc_statusa = RTCSA_DIVIDER | RTCSA_PROF;
1109 rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
1110 writertc(RTC_STATUSA, rtc_statusa);
1114 sysctl_machdep_i8254_freq SYSCTL_HANDLER_ARGS
1120 * Use `i8254' instead of `timer' in external names because `timer'
1121 * is is too generic. Should use it everywhere.
1124 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
1125 if (error == 0 && req->newptr != NULL) {
1126 if (timer0_state != RELEASED)
1127 return (EBUSY); /* too much trouble to handle */
1128 set_timer_freq(freq, hz);
1129 i8254_timecounter.tc_frequency = freq;
1130 update_timecounter(&i8254_timecounter);
1135 SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
1136 0, sizeof(u_int), sysctl_machdep_i8254_freq, "I", "");
1139 sysctl_machdep_tsc_freq SYSCTL_HANDLER_ARGS
1144 if (tsc_timecounter.tc_frequency == 0)
1145 return (EOPNOTSUPP);
1147 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
1148 if (error == 0 && req->newptr != NULL) {
1150 tsc_timecounter.tc_frequency = tsc_freq;
1151 update_timecounter(&tsc_timecounter);
1156 SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_INT | CTLFLAG_RW,
1157 0, sizeof(u_int), sysctl_machdep_tsc_freq, "I", "");
1160 i8254_get_timecount(struct timecounter *tc)
1169 /* Select timer0 and latch counter value. */
1170 outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
1172 low = inb(TIMER_CNTR0);
1173 high = inb(TIMER_CNTR0);
1174 count = timer0_max_count - ((high << 8) | low);
1175 if (count < i8254_lastcount ||
1176 (!i8254_ticked && (clkintr_pending ||
1177 ((count < 20 || (!(ef & PSL_I) && count < timer0_max_count / 2u)) &&
1179 #define lapic_irr1 ((volatile u_int *)&lapic)[0x210 / 4] /* XXX XXX */
1180 /* XXX this assumes that apic_8254_intr is < 24. */
1181 (lapic_irr1 & (1 << apic_8254_intr))))
1183 (inb(IO_ICU1) & 1)))
1187 i8254_offset += timer0_max_count;
1189 i8254_lastcount = count;
1190 count += i8254_offset;
1197 tsc_get_timecount(struct timecounter *tc)