/* $OpenBSD: clock.c,v 1.9 2006/02/12 19:55:38 miod Exp $ */ /* $NetBSD: clock.c,v 1.1 2003/04/26 18:39:50 fvdl Exp $ */ /*- * Copyright (c) 1993, 1994 Charles M. Hannum. * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * William Jolitz and Don Ahn. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. 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. * * @(#)clock.c 7.2 (Berkeley) 5/12/91 */ /* * Mach Operating System * Copyright (c) 1991,1990,1989 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* Copyright 1988, 1989 by Intel Corporation, Santa Clara, California. All Rights Reserved Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appears in all copies and that both the copyright notice and this permission notice appear in supporting documentation, and that the name of Intel not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * Primitive clock interrupt routines. */ /* #define CLOCKDEBUG */ /* #define CLOCK_PARANOIA */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include void spinwait(int); int clockintr(void *); int rtcintr(void *); int gettick(void); void rtcdrain(void *v); int rtcget(mc_todregs *); void rtcput(mc_todregs *); int bcdtobin(int); int bintobcd(int); void findcpuspeed(void); __inline u_int mc146818_read(void *, u_int); __inline void mc146818_write(void *, u_int, u_int); __inline u_int mc146818_read(sc, reg) void *sc; /* XXX use it? */ u_int reg; { outb(IO_RTC, reg); DELAY(1); return (inb(IO_RTC+1)); } __inline void mc146818_write(sc, reg, datum) void *sc; /* XXX use it? */ u_int reg, datum; { outb(IO_RTC, reg); DELAY(1); outb(IO_RTC+1, datum); DELAY(1); } u_long rtclock_tval; /* minimal initialization, enough for delay() */ void initrtclock() { u_long tval; /* * Compute timer_count, the count-down count the timer will be * set to. Also, correctly round * this by carrying an extra bit through the division. */ tval = (TIMER_FREQ * 2) / (u_long) hz; tval = (tval / 2) + (tval & 0x1); /* initialize 8253 clock */ outb(IO_TIMER1+TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT); /* Correct rounding will buy us a better precision in timekeeping */ outb(IO_TIMER1+TIMER_CNTR0, tval % 256); outb(IO_TIMER1+TIMER_CNTR0, tval / 256); rtclock_tval = tval; } /* * microtime() makes use of the following globals. Note that isa_timer_tick * may be redundant to the `tick' variable, but is kept here for stability. * isa_timer_count is the countdown count for the timer. timer_msb_table[] * and timer_lsb_table[] are used to compute the microsecond increment * for time.tv_usec in the follow fashion: * * time.tv_usec += isa_timer_msb_table[cnt_msb] - isa_timer_lsb_table[cnt_lsb]; */ #define ISA_TIMER_MSB_TABLE_SIZE 128 u_long isa_timer_tick; /* the number of microseconds in a tick */ u_short isa_timer_count; /* the countdown count for the timer */ u_short isa_timer_msb_table[ISA_TIMER_MSB_TABLE_SIZE]; /* timer->usec MSB */ u_short isa_timer_lsb_table[256]; /* timer->usec conversion for LSB */ void startrtclock() { int s; u_long tval; u_long t, msb, lsb, quotient, remainder; findcpuspeed(); /* use the clock (while it's free) to find the cpu speed */ initrtclock(); /* Check diagnostic status */ if ((s = mc146818_read(NULL, NVRAM_DIAG)) != 0) /* XXX softc */ printf("RTC BIOS diagnostic error %b\n", s, NVRAM_DIAG_BITS); /* * Compute timer_tick from hz. We truncate this value (i.e. * round down) to minimize the possibility of a backward clock * step if hz is not a nice number. */ isa_timer_tick = 1000000 / (u_long) hz; /* * We can't stand any number with an MSB larger than * TIMER_MSB_TABLE_SIZE will accomodate. */ tval = rtclock_tval; if ((tval / 256) >= ISA_TIMER_MSB_TABLE_SIZE || TIMER_FREQ > (8*1024*1024)) { panic("startrtclock: TIMER_FREQ/HZ unsupportable"); } isa_timer_count = (u_short) tval; /* * Now compute the translation tables from timer ticks to * microseconds. We go to some length to ensure all values * are rounded-to-nearest (i.e. +-0.5 of the exact values) * as this will ensure the computation * * isa_timer_msb_table[msb] - isa_timer_lsb_table[lsb] * * will produce a result which is +-1 usec away from the * correctly rounded conversion (in fact, it'll be exact about * 75% of the time, 1 too large 12.5% of the time, and 1 too * small 12.5% of the time). */ for (s = 0; s < 256; s++) { /* LSB table is easy, just divide and round */ t = ((u_long) s * 1000000 * 2) / TIMER_FREQ; isa_timer_lsb_table[s] = (u_short) ((t / 2) + (t & 0x1)); /* MSB table is zero unless the MSB is <= isa_timer_count */ if (s < ISA_TIMER_MSB_TABLE_SIZE) { msb = ((u_long) s) * 256; if (msb > tval) { isa_timer_msb_table[s] = 0; } else { /* * Harder computation here, since multiplying * the value by 1000000 can overflow a long. * To avoid 64-bit computations we divide * the high order byte and the low order * byte of the numerator separately, adding * the remainder of the first computation * into the second. The constraint on * TIMER_FREQ above should prevent overflow * here. */ msb = tval - msb; lsb = msb % 256; msb = (msb / 256) * 1000000; quotient = msb / TIMER_FREQ; remainder = msb % TIMER_FREQ; t = ((remainder * 256 * 2) + (lsb * 1000000 * 2)) / TIMER_FREQ; isa_timer_msb_table[s] = (u_short)((t / 2) + (t & 0x1) + (quotient * 256)); } } } } int clockintr(void *arg) { struct clockframe *frame = arg; hardclock(frame); return 1; } int rtcintr(void *arg) { struct clockframe *frame = arg; u_int stat = 0; /* * If rtcintr is 'late', next intr may happen immediately. * Get them all. (Also, see comment in cpu_initclocks().) */ while (mc146818_read(NULL, MC_REGC) & MC_REGC_PF) { statclock(frame); stat = 1; } return (stat); } int gettick() { u_long ef; u_char lo, hi; /* Don't want someone screwing with the counter while we're here. */ ef = read_rflags(); disable_intr(); /* Select counter 0 and latch it. */ outb(IO_TIMER1+TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); lo = inb(IO_TIMER1+TIMER_CNTR0); hi = inb(IO_TIMER1+TIMER_CNTR0); write_rflags(ef); return ((hi << 8) | lo); } /* * Wait "n" microseconds. * Relies on timer 1 counting down from (TIMER_FREQ / hz) at TIMER_FREQ Hz. * Note: timer had better have been programmed before this is first used! * (Note that we use `rate generator' mode, which counts at 1:1; `square * wave' mode counts at 2:1). */ void i8254_delay(int n) { int limit, tick, otick; static const int delaytab[26] = { 0, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 27, 28, 29, 30, }; /* allow DELAY() to be used before startrtclock() */ if (!rtclock_tval) initrtclock(); /* * Read the counter first, so that the rest of the setup overhead is * counted. */ otick = gettick(); if (n <= 25) n = delaytab[n]; else { #ifdef __GNUC__ /* * Calculate ((n * TIMER_FREQ) / 1e6) using explicit assembler * code so we can take advantage of the intermediate 64-bit * quantity to prevent loss of significance. */ int m; __asm __volatile("mul %3" : "=a" (n), "=d" (m) : "0" (n), "r" (TIMER_FREQ)); __asm __volatile("div %4" : "=a" (n), "=d" (m) : "0" (n), "1" (m), "r" (1000000)); #else /* * Calculate ((n * TIMER_FREQ) / 1e6) without using floating * point and without any avoidable overflows. */ int sec = n / 1000000, usec = n % 1000000; n = sec * TIMER_FREQ + usec * (TIMER_FREQ / 1000000) + usec * ((TIMER_FREQ % 1000000) / 1000) / 1000 + usec * (TIMER_FREQ % 1000) / 1000000; #endif } limit = TIMER_FREQ / hz; while (n > 0) { tick = gettick(); if (tick > otick) n -= limit - (tick - otick); else n -= otick - tick; otick = tick; } } unsigned int delaycount; /* calibrated loop variable (1 millisecond) */ #define FIRST_GUESS 0x2000 void findcpuspeed() { int i; int remainder; /* Put counter in count down mode */ outb(TIMER_MODE, TIMER_SEL0 | TIMER_16BIT | TIMER_RATEGEN); outb(TIMER_CNTR0, 0xff); outb(TIMER_CNTR0, 0xff); for (i = FIRST_GUESS; i; i--) ; /* Read the value left in the counter */ remainder = gettick(); /* * Formula for delaycount is: * (loopcount * timer clock speed) / (counter ticks * 1000) */ delaycount = (FIRST_GUESS * TIMER_DIV(1000)) / (0xffff-remainder); } void rtcdrain(void *v) { struct timeout *to = (struct timeout *)v; if (to != NULL) timeout_del(to); /* * Drain any un-acknowledged RTC interrupts. * See comment in cpu_initclocks(). */ while (mc146818_read(NULL, MC_REGC) & MC_REGC_PF) ; /* Nothing. */ } void i8254_initclocks() { static struct timeout rtcdrain_timeout; stathz = 128; profhz = 1024; /* * XXX If you're doing strange things with multiple clocks, you might * want to keep track of clock handlers. */ isa_intr_establish(NULL, 0, IST_PULSE, IPL_CLOCK, clockintr, 0, "clock"); isa_intr_establish(NULL, 8, IST_PULSE, IPL_CLOCK, rtcintr, 0, "rtc"); mc146818_write(NULL, MC_REGA, MC_BASE_32_KHz | MC_RATE_128_Hz); mc146818_write(NULL, MC_REGB, MC_REGB_24HR | MC_REGB_PIE); /* * On a number of i386 systems, the rtc will fail to start when booting * the system. This is due to us missing to acknowledge an interrupt * during early stages of the boot process. If we do not acknowledge * the interrupt, the rtc clock will not generate further interrupts. * To solve this, once interrupts are enabled, use a timeout (once) * to drain any un-acknowledged rtc interrupt(s). */ timeout_set(&rtcdrain_timeout, rtcdrain, (void *)&rtcdrain_timeout); timeout_add(&rtcdrain_timeout, 1); } int rtcget(regs) mc_todregs *regs; { if ((mc146818_read(NULL, MC_REGD) & MC_REGD_VRT) == 0) /* XXX softc */ return (-1); MC146818_GETTOD(NULL, regs); /* XXX softc */ return (0); } void rtcput(regs) mc_todregs *regs; { MC146818_PUTTOD(NULL, regs); /* XXX softc */ } int bcdtobin(n) int n; { return (((n >> 4) & 0x0f) * 10 + (n & 0x0f)); } int bintobcd(n) int n; { return ((u_char)(((n / 10) << 4) & 0xf0) | ((n % 10) & 0x0f)); } static int timeset; /* * check whether the CMOS layout is "standard"-like (ie, not PS/2-like), * to be called at splclock() */ static int cmoscheck(void); static int cmoscheck() { int i; unsigned short cksum = 0; for (i = 0x10; i <= 0x2d; i++) cksum += mc146818_read(NULL, i); /* XXX softc */ return (cksum == (mc146818_read(NULL, 0x2e) << 8) + mc146818_read(NULL, 0x2f)); } #if NMCA > 0 /* * Check whether the CMOS layout is PS/2 like, to be called at splclock(). */ static int cmoscheckps2(void); static int cmoscheckps2() { #if 0 /* Disabled until I find out the CRC checksum algorithm IBM uses */ int i; unsigned short cksum = 0; for (i = 0x10; i <= 0x31; i++) cksum += mc146818_read(NULL, i); /* XXX softc */ return (cksum == (mc146818_read(NULL, 0x32) << 8) + mc146818_read(NULL, 0x33)); #else /* Check 'incorrect checksum' bit of IBM PS/2 Diagnostic Status Byte */ return ((mc146818_read(NULL, NVRAM_DIAG) & (1<<6)) == 0); #endif } #endif /* NMCA > 0 */ /* * patchable to control century byte handling: * 1: always update * -1: never touch * 0: try to figure out itself */ int rtc_update_century = 0; /* * Expand a two-digit year as read from the clock chip * into full width. * Being here, deal with the CMOS century byte. */ static int centb = NVRAM_CENTURY; static int clock_expandyear(int); static int clock_expandyear(clockyear) int clockyear; { int s, clockcentury, cmoscentury; clockcentury = (clockyear < 70) ? 20 : 19; clockyear += 100 * clockcentury; if (rtc_update_century < 0) return (clockyear); s = splclock(); if (cmoscheck()) cmoscentury = mc146818_read(NULL, NVRAM_CENTURY); #if NMCA > 0 else if (MCA_system && cmoscheckps2()) cmoscentury = mc146818_read(NULL, (centb = 0x37)); #endif else cmoscentury = 0; splx(s); if (!cmoscentury) { #ifdef DIAGNOSTIC printf("clock: unknown CMOS layout\n"); #endif return (clockyear); } cmoscentury = bcdtobin(cmoscentury); if (cmoscentury != clockcentury) { /* XXX note: saying "century is 20" might confuse the naive. */ printf("WARNING: NVRAM century is %d but RTC year is %d\n", cmoscentury, clockyear); /* Kludge to roll over century. */ if ((rtc_update_century > 0) || ((cmoscentury == 19) && (clockcentury == 20) && (clockyear == 2000))) { printf("WARNING: Setting NVRAM century to %d\n", clockcentury); s = splclock(); mc146818_write(NULL, centb, bintobcd(clockcentury)); splx(s); } } else if (cmoscentury == 19 && rtc_update_century == 0) rtc_update_century = 1; /* will update later in resettodr() */ return (clockyear); } /* * Initialize the time of day register, based on the time base which is, e.g. * from a filesystem. */ void inittodr(base) time_t base; { mc_todregs rtclk; struct clock_ymdhms dt; int s; #if defined(I586_CPU) || defined(I686_CPU) struct cpu_info *ci = curcpu(); #endif /* * We mostly ignore the suggested time (which comes from the * file system) and go for the RTC clock time stored in the * CMOS RAM. If the time can't be obtained from the CMOS, or * if the time obtained from the CMOS is 5 or more years less * than the suggested time, we used the suggested time. (In * the latter case, it's likely that the CMOS battery has * died.) */ /* * if the file system time is more than a year older than the * kernel, warn and then set the base time to the CONFIG_TIME. */ if (base < 30*SECYR) { /* if before 2000, something's odd... */ printf("WARNING: preposterous time in file system\n"); base = 30*SECYR; } s = splclock(); if (rtcget(&rtclk)) { splx(s); printf("WARNING: invalid time in clock chip\n"); goto fstime; } splx(s); #ifdef DEBUG_CLOCK printf("readclock: %x/%x/%x %x:%x:%x\n", rtclk[MC_YEAR], rtclk[MC_MONTH], rtclk[MC_DOM], rtclk[MC_HOUR], rtclk[MC_MIN], rtclk[MC_SEC]); #endif dt.dt_sec = bcdtobin(rtclk[MC_SEC]); dt.dt_min = bcdtobin(rtclk[MC_MIN]); dt.dt_hour = bcdtobin(rtclk[MC_HOUR]); dt.dt_day = bcdtobin(rtclk[MC_DOM]); dt.dt_mon = bcdtobin(rtclk[MC_MONTH]); dt.dt_year = clock_expandyear(bcdtobin(rtclk[MC_YEAR])); /* * If time_t is 32 bits, then the "End of Time" is * Mon Jan 18 22:14:07 2038 (US/Eastern) * This code copes with RTC's past the end of time if time_t * is an int32 or less. Needed because sometimes RTCs screw * up or are badly set, and that would cause the time to go * negative in the calculation below, which causes Very Bad * Mojo. This at least lets the user boot and fix the problem. * Note the code is self eliminating once time_t goes to 64 bits. */ if (sizeof(time_t) <= sizeof(int32_t)) { if (dt.dt_year >= 2038) { printf("WARNING: RTC time at or beyond 2038.\n"); dt.dt_year = 2037; printf("WARNING: year set back to 2037.\n"); printf("WARNING: CHECK AND RESET THE DATE!\n"); } } time.tv_sec = clock_ymdhms_to_secs(&dt) + tz.tz_minuteswest * 60; if (tz.tz_dsttime) time.tv_sec -= 3600; #ifdef DEBUG_CLOCK printf("readclock: %ld (%ld)\n", time.tv_sec, base); #endif #if defined(I586_CPU) || defined(I686_CPU) if (ci->ci_feature_flags & CPUID_TSC) { cc_microset_time = time; cc_microset(ci); } #endif if (base != 0 && base < time.tv_sec - 5*SECYR) printf("WARNING: file system time much less than clock time\n"); else if (base > time.tv_sec + 5*SECYR) { printf("WARNING: clock time much less than file system time\n"); printf("WARNING: using file system time\n"); goto fstime; } timeset = 1; return; fstime: timeset = 1; time.tv_sec = base; printf("WARNING: CHECK AND RESET THE DATE!\n"); } /* * Reset the clock. */ void resettodr() { mc_todregs rtclk; struct clock_ymdhms dt; int century, diff, s; /* * We might have been called by boot() due to a crash early * on. Don't reset the clock chip in this case. */ if (!timeset) return; s = splclock(); if (rtcget(&rtclk)) memset(&rtclk, 0, sizeof(rtclk)); splx(s); diff = tz.tz_minuteswest * 60; if (tz.tz_dsttime) diff -= 3600; clock_secs_to_ymdhms(time.tv_sec - diff, &dt); rtclk[MC_SEC] = bintobcd(dt.dt_sec); rtclk[MC_MIN] = bintobcd(dt.dt_min); rtclk[MC_HOUR] = bintobcd(dt.dt_hour); rtclk[MC_DOW] = dt.dt_wday + 1; rtclk[MC_YEAR] = bintobcd(dt.dt_year % 100); rtclk[MC_MONTH] = bintobcd(dt.dt_mon); rtclk[MC_DOM] = bintobcd(dt.dt_day); #ifdef DEBUG_CLOCK printf("setclock: %x/%x/%x %x:%x:%x\n", rtclk[MC_YEAR], rtclk[MC_MONTH], rtclk[MC_DOM], rtclk[MC_HOUR], rtclk[MC_MIN], rtclk[MC_SEC]); #endif s = splclock(); rtcput(&rtclk); if (rtc_update_century > 0) { century = bintobcd(dt.dt_year / 100); mc146818_write(NULL, centb, century); /* XXX softc */ } splx(s); } void setstatclockrate(arg) int arg; { if (arg == stathz) mc146818_write(NULL, MC_REGA, MC_BASE_32_KHz | MC_RATE_128_Hz); else mc146818_write(NULL, MC_REGA, MC_BASE_32_KHz | MC_RATE_1024_Hz); }