/*- * 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. * 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 */ #include __FBSDID("$FreeBSD$"); /* * Routines to handle clock hardware. */ /* * inittodr, settodr and support routines written * by Christoph Robitschko * * reintroduced and updated by Chris Stenton 8/10/94 */ #include "opt_clock.h" #include "opt_isa.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DEV_ISA #include #include #endif /* * 32-bit time_t's can't reach leap years before 1904 or after 2036, so we * can use a simple formula for leap years. */ #define LEAPYEAR(y) (((u_int)(y) % 4 == 0) ? 1 : 0) #define DAYSPERYEAR (31+28+31+30+31+30+31+31+30+31+30+31) #define TIMER_DIV(x) ((timer_freq + (x) / 2) / (x)) int adjkerntz; /* local offset from GMT in seconds */ int clkintr_pending; int disable_rtc_set; /* disable resettodr() if != 0 */ int pscnt = 1; int psdiv = 1; int statclock_disable; #ifndef TIMER_FREQ #define TIMER_FREQ 1193182 #endif u_int timer_freq = TIMER_FREQ; int timer0_max_count; int timer0_real_max_count; int wall_cmos_clock; /* wall CMOS clock assumed if != 0 */ struct mtx clock_lock; #define RTC_LOCK mtx_lock_spin(&clock_lock) #define RTC_UNLOCK mtx_unlock_spin(&clock_lock) static int beeping = 0; static const u_char daysinmonth[] = {31,28,31,30,31,30,31,31,30,31,30,31}; static struct intsrc *i8254_intsrc; static u_int32_t i8254_lastcount; static u_int32_t i8254_offset; static int (*i8254_pending)(struct intsrc *); static int i8254_ticked; static int using_lapic_timer; static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF; static u_char rtc_statusb = RTCSB_24HR; /* Values for timerX_state: */ #define RELEASED 0 #define RELEASE_PENDING 1 #define ACQUIRED 2 #define ACQUIRE_PENDING 3 static u_char timer2_state; static unsigned i8254_get_timecount(struct timecounter *tc); static unsigned i8254_simple_get_timecount(struct timecounter *tc); static void set_timer_freq(u_int freq, int intr_freq); static struct timecounter i8254_timecounter = { i8254_get_timecount, /* get_timecount */ 0, /* no poll_pps */ ~0u, /* counter_mask */ 0, /* frequency */ "i8254", /* name */ 0 /* quality */ }; static void clkintr(struct clockframe *frame) { if (timecounter->tc_get_timecount == i8254_get_timecount) { mtx_lock_spin(&clock_lock); if (i8254_ticked) i8254_ticked = 0; else { i8254_offset += timer0_max_count; i8254_lastcount = 0; } clkintr_pending = 0; mtx_unlock_spin(&clock_lock); } if (!using_lapic_timer) hardclock(frame); } int acquire_timer2(int mode) { if (timer2_state != RELEASED) return (-1); timer2_state = ACQUIRED; /* * This access to the timer registers is as atomic as possible * because it is a single instruction. We could do better if we * knew the rate. Use of splclock() limits glitches to 10-100us, * and this is probably good enough for timer2, so we aren't as * careful with it as with timer0. */ outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f)); return (0); } int release_timer2() { if (timer2_state != ACQUIRED) return (-1); timer2_state = RELEASED; outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT); return (0); } /* * This routine receives statistical clock interrupts from the RTC. * As explained above, these occur at 128 interrupts per second. * When profiling, we receive interrupts at a rate of 1024 Hz. * * This does not actually add as much overhead as it sounds, because * when the statistical clock is active, the hardclock driver no longer * needs to keep (inaccurate) statistics on its own. This decouples * statistics gathering from scheduling interrupts. * * The RTC chip requires that we read status register C (RTC_INTR) * to acknowledge an interrupt, before it will generate the next one. * Under high interrupt load, rtcintr() can be indefinitely delayed and * the clock can tick immediately after the read from RTC_INTR. In this * case, the mc146818A interrupt signal will not drop for long enough * to register with the 8259 PIC. If an interrupt is missed, the stat * clock will halt, considerably degrading system performance. This is * why we use 'while' rather than a more straightforward 'if' below. * Stat clock ticks can still be lost, causing minor loss of accuracy * in the statistics, but the stat clock will no longer stop. */ static void rtcintr(struct clockframe *frame) { while (rtcin(RTC_INTR) & RTCIR_PERIOD) { if (profprocs != 0) { if (--pscnt == 0) pscnt = psdiv; profclock(frame); } if (pscnt == psdiv) statclock(frame); } } #include "opt_ddb.h" #ifdef DDB #include DB_SHOW_COMMAND(rtc, rtc) { printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n", rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY), rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC), rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR)); } #endif /* DDB */ static int getit(void) { int high, low; mtx_lock_spin(&clock_lock); /* Select timer0 and latch counter value. */ outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); low = inb(TIMER_CNTR0); high = inb(TIMER_CNTR0); mtx_unlock_spin(&clock_lock); return ((high << 8) | low); } /* * Wait "n" microseconds. * Relies on timer 1 counting down from (timer_freq / hz) * Note: timer had better have been programmed before this is first used! */ void DELAY(int n) { int delta, prev_tick, tick, ticks_left; #ifdef DELAYDEBUG int getit_calls = 1; int n1; static int state = 0; if (state == 0) { state = 1; for (n1 = 1; n1 <= 10000000; n1 *= 10) DELAY(n1); state = 2; } if (state == 1) printf("DELAY(%d)...", n); #endif /* * Guard against the timer being uninitialized if we are called * early for console i/o. */ if (timer0_max_count == 0) set_timer_freq(timer_freq, hz); /* * Read the counter first, so that the rest of the setup overhead is * counted. Guess the initial overhead is 20 usec (on most systems it * takes about 1.5 usec for each of the i/o's in getit(). The loop * takes about 6 usec on a 486/33 and 13 usec on a 386/20. The * multiplications and divisions to scale the count take a while). * * However, if ddb is active then use a fake counter since reading * the i8254 counter involves acquiring a lock. ddb must not do * locking for many reasons, but it calls here for at least atkbd * input. */ #ifdef KDB if (kdb_active) prev_tick = 1; else #endif prev_tick = getit(); n -= 0; /* XXX actually guess no initial overhead */ /* * Calculate (n * (timer_freq / 1e6)) without using floating point * and without any avoidable overflows. */ if (n <= 0) ticks_left = 0; else if (n < 256) /* * Use fixed point to avoid a slow division by 1000000. * 39099 = 1193182 * 2^15 / 10^6 rounded to nearest. * 2^15 is the first power of 2 that gives exact results * for n between 0 and 256. */ ticks_left = ((u_int)n * 39099 + (1 << 15) - 1) >> 15; else /* * Don't bother using fixed point, although gcc-2.7.2 * generates particularly poor code for the long long * division, since even the slow way will complete long * before the delay is up (unless we're interrupted). */ ticks_left = ((u_int)n * (long long)timer_freq + 999999) / 1000000; while (ticks_left > 0) { #ifdef KDB if (kdb_active) { inb(0x84); tick = prev_tick - 1; if (tick <= 0) tick = timer0_max_count; } else #endif tick = getit(); #ifdef DELAYDEBUG ++getit_calls; #endif delta = prev_tick - tick; prev_tick = tick; if (delta < 0) { delta += timer0_max_count; /* * Guard against timer0_max_count being wrong. * This shouldn't happen in normal operation, * but it may happen if set_timer_freq() is * traced. */ if (delta < 0) delta = 0; } ticks_left -= delta; } #ifdef DELAYDEBUG if (state == 1) printf(" %d calls to getit() at %d usec each\n", getit_calls, (n + 5) / getit_calls); #endif } static void sysbeepstop(void *chan) { ppi_spkr_off(); /* disable counter2 output to speaker */ timer_spkr_release(); beeping = 0; } int sysbeep(int pitch, int period) { int x = splclock(); if (timer_spkr_acquire()) if (!beeping) { /* Something else owns it. */ splx(x); return (-1); /* XXX Should be EBUSY, but nobody cares anyway. */ } mtx_lock_spin(&clock_lock); spkr_set_pitch(pitch); mtx_unlock_spin(&clock_lock); if (!beeping) { /* enable counter2 output to speaker */ ppi_spkr_on(); beeping = period; timeout(sysbeepstop, (void *)NULL, period); } splx(x); return (0); } /* * RTC support routines */ int rtcin(reg) int reg; { u_char val; RTC_LOCK; outb(IO_RTC, reg); inb(0x84); val = inb(IO_RTC + 1); inb(0x84); RTC_UNLOCK; return (val); } static __inline void writertc(u_char reg, u_char val) { RTC_LOCK; inb(0x84); outb(IO_RTC, reg); inb(0x84); outb(IO_RTC + 1, val); inb(0x84); /* XXX work around wrong order in rtcin() */ RTC_UNLOCK; } static __inline int readrtc(int port) { return(bcd2bin(rtcin(port))); } static u_int calibrate_clocks(void) { u_int count, prev_count, tot_count; int sec, start_sec, timeout; if (bootverbose) printf("Calibrating clock(s) ... "); if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) goto fail; timeout = 100000000; /* Read the mc146818A seconds counter. */ for (;;) { if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) { sec = rtcin(RTC_SEC); break; } if (--timeout == 0) goto fail; } /* Wait for the mC146818A seconds counter to change. */ start_sec = sec; for (;;) { if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) { sec = rtcin(RTC_SEC); if (sec != start_sec) break; } if (--timeout == 0) goto fail; } /* Start keeping track of the i8254 counter. */ prev_count = getit(); if (prev_count == 0 || prev_count > timer0_max_count) goto fail; tot_count = 0; /* * Wait for the mc146818A seconds counter to change. Read the i8254 * counter for each iteration since this is convenient and only * costs a few usec of inaccuracy. The timing of the final reads * of the counters almost matches the timing of the initial reads, * so the main cause of inaccuracy is the varying latency from * inside getit() or rtcin(RTC_STATUSA) to the beginning of the * rtcin(RTC_SEC) that returns a changed seconds count. The * maximum inaccuracy from this cause is < 10 usec on 486's. */ start_sec = sec; for (;;) { if (!(rtcin(RTC_STATUSA) & RTCSA_TUP)) sec = rtcin(RTC_SEC); count = getit(); if (count == 0 || count > timer0_max_count) goto fail; if (count > prev_count) tot_count += prev_count - (count - timer0_max_count); else tot_count += prev_count - count; prev_count = count; if (sec != start_sec) break; if (--timeout == 0) goto fail; } if (bootverbose) { printf("i8254 clock: %u Hz\n", tot_count); } return (tot_count); fail: if (bootverbose) printf("failed, using default i8254 clock of %u Hz\n", timer_freq); return (timer_freq); } static void set_timer_freq(u_int freq, int intr_freq) { int new_timer0_real_max_count; i8254_timecounter.tc_frequency = freq; mtx_lock_spin(&clock_lock); timer_freq = freq; if (using_lapic_timer) new_timer0_real_max_count = 0x10000; else new_timer0_real_max_count = TIMER_DIV(intr_freq); if (new_timer0_real_max_count != timer0_real_max_count) { timer0_real_max_count = new_timer0_real_max_count; if (timer0_real_max_count == 0x10000) timer0_max_count = 0xffff; else timer0_max_count = timer0_real_max_count; outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT); outb(TIMER_CNTR0, timer0_real_max_count & 0xff); outb(TIMER_CNTR0, timer0_real_max_count >> 8); } mtx_unlock_spin(&clock_lock); } /* * Initialize 8254 timer 0 early so that it can be used in DELAY(). * XXX initialization of other timers is unintentionally left blank. */ void startrtclock() { u_int delta, freq; writertc(RTC_STATUSA, rtc_statusa); writertc(RTC_STATUSB, RTCSB_24HR); set_timer_freq(timer_freq, hz); freq = calibrate_clocks(); #ifdef CLK_CALIBRATION_LOOP if (bootverbose) { printf( "Press a key on the console to abort clock calibration\n"); while (cncheckc() == -1) calibrate_clocks(); } #endif /* * Use the calibrated i8254 frequency if it seems reasonable. * Otherwise use the default, and don't use the calibrated i586 * frequency. */ delta = freq > timer_freq ? freq - timer_freq : timer_freq - freq; if (delta < timer_freq / 100) { #ifndef CLK_USE_I8254_CALIBRATION if (bootverbose) printf( "CLK_USE_I8254_CALIBRATION not specified - using default frequency\n"); freq = timer_freq; #endif timer_freq = freq; } else { if (bootverbose) printf( "%d Hz differs from default of %d Hz by more than 1%%\n", freq, timer_freq); } set_timer_freq(timer_freq, hz); tc_init(&i8254_timecounter); init_TSC(); } /* * Initialize the time of day register, based on the time base which is, e.g. * from a filesystem. */ void inittodr(time_t base) { unsigned long sec, days; int year, month; int y, m, s; struct timespec ts; if (base) { s = splclock(); ts.tv_sec = base; ts.tv_nsec = 0; tc_setclock(&ts); splx(s); } /* Look if we have a RTC present and the time is valid */ if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) goto wrong_time; /* wait for time update to complete */ /* If RTCSA_TUP is zero, we have at least 244us before next update */ s = splhigh(); while (rtcin(RTC_STATUSA) & RTCSA_TUP) { splx(s); s = splhigh(); } days = 0; #ifdef USE_RTC_CENTURY year = readrtc(RTC_YEAR) + readrtc(RTC_CENTURY) * 100; #else year = readrtc(RTC_YEAR) + 1900; if (year < 1970) year += 100; #endif if (year < 1970) { splx(s); goto wrong_time; } month = readrtc(RTC_MONTH); for (m = 1; m < month; m++) days += daysinmonth[m-1]; if ((month > 2) && LEAPYEAR(year)) days ++; days += readrtc(RTC_DAY) - 1; for (y = 1970; y < year; y++) days += DAYSPERYEAR + LEAPYEAR(y); sec = ((( days * 24 + readrtc(RTC_HRS)) * 60 + readrtc(RTC_MIN)) * 60 + readrtc(RTC_SEC)); /* sec now contains the number of seconds, since Jan 1 1970, in the local time zone */ sec += tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0); y = time_second - sec; if (y <= -2 || y >= 2) { /* badly off, adjust it */ ts.tv_sec = sec; ts.tv_nsec = 0; tc_setclock(&ts); } splx(s); return; wrong_time: printf("Invalid time in real time clock.\n"); printf("Check and reset the date immediately!\n"); } /* * Write system time back to RTC */ void resettodr() { unsigned long tm; int y, m, s; if (disable_rtc_set) return; s = splclock(); tm = time_second; splx(s); /* Disable RTC updates and interrupts. */ writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR); /* Calculate local time to put in RTC */ tm -= tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0); writertc(RTC_SEC, bin2bcd(tm%60)); tm /= 60; /* Write back Seconds */ writertc(RTC_MIN, bin2bcd(tm%60)); tm /= 60; /* Write back Minutes */ writertc(RTC_HRS, bin2bcd(tm%24)); tm /= 24; /* Write back Hours */ /* We have now the days since 01-01-1970 in tm */ writertc(RTC_WDAY, (tm + 4) % 7 + 1); /* Write back Weekday */ for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y); tm >= m; y++, m = DAYSPERYEAR + LEAPYEAR(y)) tm -= m; /* Now we have the years in y and the day-of-the-year in tm */ writertc(RTC_YEAR, bin2bcd(y%100)); /* Write back Year */ #ifdef USE_RTC_CENTURY writertc(RTC_CENTURY, bin2bcd(y/100)); /* ... and Century */ #endif for (m = 0; ; m++) { int ml; ml = daysinmonth[m]; if (m == 1 && LEAPYEAR(y)) ml++; if (tm < ml) break; tm -= ml; } writertc(RTC_MONTH, bin2bcd(m + 1)); /* Write back Month */ writertc(RTC_DAY, bin2bcd(tm + 1)); /* Write back Month Day */ /* Reenable RTC updates and interrupts. */ writertc(RTC_STATUSB, rtc_statusb); rtcin(RTC_INTR); } /* * Start both clocks running. */ void cpu_initclocks() { int diag; using_lapic_timer = lapic_setup_clock(); /* * If we aren't using the local APIC timer to drive the kernel * clocks, setup the interrupt handler for the 8254 timer 0 so * that it can drive hardclock(). Otherwise, change the 8254 * timecounter to user a simpler algorithm. */ if (!using_lapic_timer) { intr_add_handler("clk", 0, (driver_intr_t *)clkintr, NULL, INTR_TYPE_CLK | INTR_FAST, NULL); i8254_intsrc = intr_lookup_source(0); if (i8254_intsrc != NULL) i8254_pending = i8254_intsrc->is_pic->pic_source_pending; } else { i8254_timecounter.tc_get_timecount = i8254_simple_get_timecount; i8254_timecounter.tc_counter_mask = 0xffff; set_timer_freq(timer_freq, hz); } /* Initialize RTC. */ writertc(RTC_STATUSA, rtc_statusa); writertc(RTC_STATUSB, RTCSB_24HR); /* * If the separate statistics clock hasn't been explicility disabled * and we aren't already using the local APIC timer to drive the * kernel clocks, then setup the RTC to periodically interrupt to * drive statclock() and profclock(). */ if (!statclock_disable && !using_lapic_timer) { diag = rtcin(RTC_DIAG); if (diag != 0) printf("RTC BIOS diagnostic error %b\n", diag, RTCDG_BITS); /* Setting stathz to nonzero early helps avoid races. */ stathz = RTC_NOPROFRATE; profhz = RTC_PROFRATE; /* Enable periodic interrupts from the RTC. */ rtc_statusb |= RTCSB_PINTR; intr_add_handler("rtc", 8, (driver_intr_t *)rtcintr, NULL, INTR_TYPE_CLK | INTR_FAST, NULL); writertc(RTC_STATUSB, rtc_statusb); rtcin(RTC_INTR); } init_TSC_tc(); } void cpu_startprofclock(void) { if (using_lapic_timer) return; rtc_statusa = RTCSA_DIVIDER | RTCSA_PROF; writertc(RTC_STATUSA, rtc_statusa); psdiv = pscnt = psratio; } void cpu_stopprofclock(void) { if (using_lapic_timer) return; rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF; writertc(RTC_STATUSA, rtc_statusa); psdiv = pscnt = 1; } static int sysctl_machdep_i8254_freq(SYSCTL_HANDLER_ARGS) { int error; u_int freq; /* * Use `i8254' instead of `timer' in external names because `timer' * is is too generic. Should use it everywhere. */ freq = timer_freq; error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); if (error == 0 && req->newptr != NULL) set_timer_freq(freq, hz); return (error); } SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW, 0, sizeof(u_int), sysctl_machdep_i8254_freq, "IU", ""); static unsigned i8254_simple_get_timecount(struct timecounter *tc) { return (timer0_max_count - getit()); } static unsigned i8254_get_timecount(struct timecounter *tc) { u_int count; u_int high, low; u_long rflags; rflags = read_rflags(); mtx_lock_spin(&clock_lock); /* Select timer0 and latch counter value. */ outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); low = inb(TIMER_CNTR0); high = inb(TIMER_CNTR0); count = timer0_max_count - ((high << 8) | low); if (count < i8254_lastcount || (!i8254_ticked && (clkintr_pending || ((count < 20 || (!(rflags & PSL_I) && count < timer0_max_count / 2u)) && i8254_pending != NULL && i8254_pending(i8254_intsrc))))) { i8254_ticked = 1; i8254_offset += timer0_max_count; } i8254_lastcount = count; count += i8254_offset; mtx_unlock_spin(&clock_lock); return (count); } #ifdef DEV_ISA /* * Attach to the ISA PnP descriptors for the timer and realtime clock. */ static struct isa_pnp_id attimer_ids[] = { { 0x0001d041 /* PNP0100 */, "AT timer" }, { 0x000bd041 /* PNP0B00 */, "AT realtime clock" }, { 0 } }; static int attimer_probe(device_t dev) { int result; if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids)) <= 0) device_quiet(dev); return(result); } static int attimer_attach(device_t dev) { return(0); } static device_method_t attimer_methods[] = { /* Device interface */ DEVMETHOD(device_probe, attimer_probe), DEVMETHOD(device_attach, attimer_attach), DEVMETHOD(device_detach, bus_generic_detach), DEVMETHOD(device_shutdown, bus_generic_shutdown), DEVMETHOD(device_suspend, bus_generic_suspend), /* XXX stop statclock? */ DEVMETHOD(device_resume, bus_generic_resume), /* XXX restart statclock? */ { 0, 0 } }; static driver_t attimer_driver = { "attimer", attimer_methods, 1, /* no softc */ }; static devclass_t attimer_devclass; DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0); DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0); #endif /* DEV_ISA */