f1b21e2c92
Most realtime clocks store the year as 2 BCD digits. Some add a century bit to extend the range another hundred years. Every clock driver has its own code to determine the century and pass a full year value to clock_ct_to_ts(). Now clock drivers can just convert BCD to bin and store the result in the clocktime struct and let the common code figure out the century. Clocks with a century bit can just add 100 to year if the century bit is on.
267 lines
7.5 KiB
C
267 lines
7.5 KiB
C
/*-
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* Copyright (c) 1988 University of Utah.
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* Copyright (c) 1982, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Utah $Hdr: clock.c 1.18 91/01/21$
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* from: @(#)clock.c 8.2 (Berkeley) 1/12/94
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* from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
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* and
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* from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/bus.h>
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#include <sys/clock.h>
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#include <sys/limits.h>
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#include <sys/sysctl.h>
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#include <sys/timetc.h>
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int tz_minuteswest;
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int tz_dsttime;
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/*
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* The adjkerntz and wall_cmos_clock sysctls are in the "machdep" sysctl
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* namespace because they were misplaced there originally.
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*/
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static int adjkerntz;
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static int
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sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
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{
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int error;
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error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
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if (!error && req->newptr)
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resettodr();
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return (error);
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}
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SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT | CTLFLAG_RW |
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CTLFLAG_MPSAFE, &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
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"Local offset from UTC in seconds");
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static int ct_debug;
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SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN,
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&ct_debug, 0, "Enable printing of clocktime debugging");
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static int wall_cmos_clock;
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SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock, CTLFLAG_RW,
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&wall_cmos_clock, 0, "Enables application of machdep.adjkerntz");
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/*--------------------------------------------------------------------*
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* Generic routines to convert between a POSIX date
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* (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
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* Derived from NetBSD arch/hp300/hp300/clock.c
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*/
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#define FEBRUARY 2
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#define days_in_year(y) (leapyear(y) ? 366 : 365)
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#define days_in_month(y, m) \
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(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
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/* Day of week. Days are counted from 1/1/1970, which was a Thursday */
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#define day_of_week(days) (((days) + 4) % 7)
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static const int month_days[12] = {
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31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
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};
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/*
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* Optimization: using a precomputed count of days between POSIX_BASE_YEAR and
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* some recent year avoids lots of unnecessary loop iterations in conversion.
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* recent_base_days is the number of days before the start of recent_base_year.
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*/
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static const int recent_base_year = 2017;
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static const int recent_base_days = 17167;
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/*
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* This inline avoids some unnecessary modulo operations
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* as compared with the usual macro:
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* ( ((year % 4) == 0 &&
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* (year % 100) != 0) ||
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* ((year % 400) == 0) )
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* It is otherwise equivalent.
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*/
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static int
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leapyear(int year)
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{
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int rv = 0;
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if ((year & 3) == 0) {
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rv = 1;
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if ((year % 100) == 0) {
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rv = 0;
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if ((year % 400) == 0)
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rv = 1;
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}
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}
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return (rv);
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}
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static void
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print_ct(struct clocktime *ct)
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{
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printf("[%04d-%02d-%02d %02d:%02d:%02d]",
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ct->year, ct->mon, ct->day,
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ct->hour, ct->min, ct->sec);
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}
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int
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clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
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{
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int i, year, days;
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if (ct_debug) {
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printf("ct_to_ts(");
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print_ct(ct);
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printf(")");
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}
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/*
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* Many realtime clocks store the year as 2-digit BCD; pivot on 70 to
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* determine century. Some clocks have a "century bit" and drivers do
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* year += 100, so interpret values between 70-199 as relative to 1900.
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*/
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year = ct->year;
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if (year < 70)
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year += 2000;
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else if (year < 200)
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year += 1900;
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/* Sanity checks. */
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if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
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ct->day > days_in_month(year, ct->mon) ||
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ct->hour > 23 || ct->min > 59 || ct->sec > 59 || year < 1970 ||
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(sizeof(time_t) == 4 && year > 2037)) { /* time_t overflow */
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if (ct_debug)
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printf(" = EINVAL\n");
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return (EINVAL);
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}
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/*
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* Compute days since start of time
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* First from years, then from months.
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*/
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if (year >= recent_base_year) {
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i = recent_base_year;
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days = recent_base_days;
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} else {
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i = POSIX_BASE_YEAR;
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days = 0;
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}
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for (; i < year; i++)
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days += days_in_year(i);
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/* Months */
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for (i = 1; i < ct->mon; i++)
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days += days_in_month(year, i);
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days += (ct->day - 1);
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ts->tv_sec = (((time_t)days * 24 + ct->hour) * 60 + ct->min) * 60 +
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ct->sec;
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ts->tv_nsec = ct->nsec;
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if (ct_debug)
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printf(" = %jd.%09ld\n", (intmax_t)ts->tv_sec, ts->tv_nsec);
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return (0);
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}
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void
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clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
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{
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time_t i, year, days;
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time_t rsec; /* remainder seconds */
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time_t secs;
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secs = ts->tv_sec;
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days = secs / SECDAY;
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rsec = secs % SECDAY;
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ct->dow = day_of_week(days);
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/* Subtract out whole years. */
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if (days >= recent_base_days) {
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year = recent_base_year;
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days -= recent_base_days;
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} else {
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year = POSIX_BASE_YEAR;
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}
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for (; days >= days_in_year(year); year++)
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days -= days_in_year(year);
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ct->year = year;
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/* Subtract out whole months, counting them in i. */
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for (i = 1; days >= days_in_month(year, i); i++)
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days -= days_in_month(year, i);
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ct->mon = i;
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/* Days are what is left over (+1) from all that. */
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ct->day = days + 1;
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/* Hours, minutes, seconds are easy */
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ct->hour = rsec / 3600;
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rsec = rsec % 3600;
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ct->min = rsec / 60;
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rsec = rsec % 60;
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ct->sec = rsec;
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ct->nsec = ts->tv_nsec;
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if (ct_debug) {
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printf("ts_to_ct(%jd.%09ld) = ",
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(intmax_t)ts->tv_sec, ts->tv_nsec);
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print_ct(ct);
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printf("\n");
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}
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KASSERT(ct->year >= 0 && ct->year < 10000,
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("year %d isn't a 4 digit year", ct->year));
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KASSERT(ct->mon >= 1 && ct->mon <= 12,
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("month %d not in 1-12", ct->mon));
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KASSERT(ct->day >= 1 && ct->day <= 31,
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("day %d not in 1-31", ct->day));
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KASSERT(ct->hour >= 0 && ct->hour <= 23,
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("hour %d not in 0-23", ct->hour));
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KASSERT(ct->min >= 0 && ct->min <= 59,
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("minute %d not in 0-59", ct->min));
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/* Not sure if this interface needs to handle leapseconds or not. */
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KASSERT(ct->sec >= 0 && ct->sec <= 60,
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("seconds %d not in 0-60", ct->sec));
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}
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int
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utc_offset(void)
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{
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return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
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}
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