subr_clock.c

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    1 /*
    2  * Copyright (c) 1988 University of Utah.
    3  * Copyright (c) 1982, 1990, 1993
    4  *      The Regents of the University of California.  All rights reserved.
    5  *
    6  * This code is derived from software contributed to Berkeley by
    7  * the Systems Programming Group of the University of Utah Computer
    8  * Science Department.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by the University of
   21  *      California, Berkeley and its contributors.
   22  * 4. Neither the name of the University nor the names of its contributors
   23  *    may be used to endorse or promote products derived from this software
   24  *    without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      from: Utah $Hdr: clock.c 1.18 91/01/21$
   39  *      from: @(#)clock.c       8.2 (Berkeley) 1/12/94
   40  *      from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
   41  *      and
   42  *      from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
   43  *
   44  * $FreeBSD: releng/5.0/sys/kern/subr_clock.c 101484 2002-08-07 19:43:54Z tmm $
   45  */
   46 
   47 /*
   48  * Helpers for time-of-day clocks. This is useful for architectures that need
   49  * support multiple models of such clocks, and generally serves to make the
   50  * code more machine-independent.
   51  * If the clock in question can also be used as a time counter, the driver
   52  * needs to initiate this.
   53  * This code is not yet used by all architectures.
   54  */
   55 
   56 /*
   57  * Generic routines to convert between a POSIX date
   58  * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
   59  * Derived from NetBSD arch/hp300/hp300/clock.c
   60  */
   61 #include <sys/param.h>
   62 #include <sys/systm.h>
   63 #include <sys/kernel.h>
   64 #include <sys/bus.h>
   65 #include <sys/clock.h>
   66 #include <sys/sysctl.h>
   67 #include <sys/timetc.h>
   68 
   69 /* XXX: for the  CPU_* sysctl OID constants. */
   70 #include <machine/cpu.h>
   71 
   72 #include "clock_if.h"
   73 
   74 static __inline int leapyear(int year);
   75 static int sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS);
   76 
   77 #define FEBRUARY        2
   78 #define days_in_year(y)         (leapyear(y) ? 366 : 365)
   79 #define days_in_month(y, m) \
   80         (month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
   81 /* Day of week. Days are counted from 1/1/1970, which was a Thursday */
   82 #define day_of_week(days)       (((days) + 4) % 7)
   83 
   84 static const int month_days[12] = {
   85         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
   86 };
   87 
   88 static device_t clock_dev = NULL;
   89 static long clock_res;
   90 
   91 int adjkerntz;          /* local offset from GMT in seconds */
   92 int disable_rtc_set;    /* disable resettodr() if != 0 */
   93 int wall_cmos_clock;    /* wall CMOS clock assumed if != 0 */
   94 
   95 /*
   96  * These have traditionally been in machdep, but should probably be moved to
   97  * kern.
   98  */
   99 SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
  100         &adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
  101 
  102 SYSCTL_INT(_machdep, CPU_DISRTCSET, disable_rtc_set,
  103         CTLFLAG_RW, &disable_rtc_set, 0, "");
  104 
  105 SYSCTL_INT(_machdep, CPU_WALLCLOCK, wall_cmos_clock,
  106         CTLFLAG_RW, &wall_cmos_clock, 0, "");
  107 
  108 static int
  109 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
  110 {
  111         int error;
  112         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
  113                 req);
  114         if (!error && req->newptr)
  115                 resettodr();
  116         return (error);
  117 }
  118 
  119 /*
  120  * This inline avoids some unnecessary modulo operations
  121  * as compared with the usual macro:
  122  *   ( ((year % 4) == 0 &&
  123  *      (year % 100) != 0) ||
  124  *     ((year % 400) == 0) )
  125  * It is otherwise equivalent.
  126  */
  127 static __inline int
  128 leapyear(int year)
  129 {
  130         int rv = 0;
  131 
  132         if ((year & 3) == 0) {
  133                 rv = 1;
  134                 if ((year % 100) == 0) {
  135                         rv = 0;
  136                         if ((year % 400) == 0)
  137                                 rv = 1;
  138                 }
  139         }
  140         return (rv);
  141 }
  142 
  143 int
  144 clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
  145 {
  146         time_t secs;
  147         int i, year, days;
  148 
  149         year = ct->year;
  150 
  151         /* Sanity checks. */
  152         if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
  153             ct->day > days_in_month(year, ct->mon) ||
  154             ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 ||
  155             ct->year > 2037)            /* time_t overflow */
  156                 return (EINVAL);
  157 
  158         /*
  159          * Compute days since start of time
  160          * First from years, then from months.
  161          */
  162         days = 0;
  163         for (i = POSIX_BASE_YEAR; i < year; i++)
  164                 days += days_in_year(i);
  165 
  166         /* Months */
  167         for (i = 1; i < ct->mon; i++)
  168                 days += days_in_month(year, i);
  169         days += (ct->day - 1);
  170 
  171         /* Another sanity check. */
  172         if (ct->dow != -1 && ct->dow != day_of_week(days))
  173                 return (EINVAL);
  174 
  175         /* Add hours, minutes, seconds. */
  176         secs = ((days * 24 + ct->hour) * 60 + ct->min) * 60 + ct->sec;
  177 
  178         ts->tv_sec = secs;
  179         ts->tv_nsec = ct->nsec;
  180         return (0);
  181 }
  182 
  183 void
  184 clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
  185 {
  186         int i, year, days;
  187         time_t rsec;    /* remainder seconds */
  188         time_t secs;
  189 
  190         secs = ts->tv_sec;
  191         days = secs / SECDAY;
  192         rsec = secs % SECDAY;
  193 
  194         ct->dow = day_of_week(days);
  195 
  196         /* Subtract out whole years, counting them in i. */
  197         for (year = POSIX_BASE_YEAR; days >= days_in_year(year); year++)
  198                 days -= days_in_year(year);
  199         ct->year = year;
  200 
  201         /* Subtract out whole months, counting them in i. */
  202         for (i = 1; days >= days_in_month(year, i); i++)
  203                 days -= days_in_month(year, i);
  204         ct->mon = i;
  205 
  206         /* Days are what is left over (+1) from all that. */
  207         ct->day = days + 1;
  208 
  209         /* Hours, minutes, seconds are easy */
  210         ct->hour = rsec / 3600;
  211         rsec = rsec % 3600;
  212         ct->min  = rsec / 60;
  213         rsec = rsec % 60;
  214         ct->sec  = rsec;
  215         ct->nsec = ts->tv_nsec;
  216 }
  217 
  218 void
  219 clock_register(device_t dev, long res)
  220 {
  221 
  222         if (clock_dev != NULL) {
  223                 if (clock_res > res) {
  224                         if (bootverbose) {
  225                                 device_printf(dev, "not installed as "
  226                                     "time-of-day clock: clock %s has higher "
  227                                     "resolution\n", device_get_name(clock_dev));
  228                         }
  229                         return;
  230                 } else {
  231                         if (bootverbose) {
  232                                 device_printf(clock_dev, "removed as "
  233                                     "time-of-day clock: clock %s has higher "
  234                                     "resolution\n", device_get_name(dev));
  235                         }
  236                 }
  237         }
  238         clock_dev = dev;
  239         clock_res = res;
  240         if (bootverbose) {
  241                 device_printf(dev, "registered as a time-of-day clock "
  242                     "(resolution %ldus)\n", res);
  243         }
  244 }
  245 
  246 /*
  247  * inittodr and settodr derived from the i386 versions written
  248  * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>,  reintroduced and
  249  * updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
  250  */
  251 
  252 /*
  253  * Initialize the time of day register, based on the time base which is, e.g.
  254  * from a filesystem.
  255  */
  256 void
  257 inittodr(time_t base)
  258 {
  259         struct timespec diff, ref, ts;
  260         int error;
  261 
  262         if (base) {
  263                 ref.tv_sec = base;
  264                 ref.tv_nsec = 0;
  265                 tc_setclock(&ref);
  266         }
  267 
  268         if (clock_dev == NULL) {
  269                 printf("warning: no time-of-day clock registered, system time "
  270                     "will not be set accurately\n");
  271                 return;
  272         }
  273         error = CLOCK_GETTIME(clock_dev, &ts);
  274         if (error != 0 && error != EINVAL) {
  275                 printf("warning: clock_gettime failed (%d), the system time "
  276                     "will not be set accurately\n", error);
  277                 return;
  278         }
  279         if (error == EINVAL || ts.tv_sec < 0) {
  280                 printf("Invalid time in real time clock.\n");
  281                 printf("Check and reset the date immediately!\n");
  282         }
  283 
  284         ts.tv_sec += tz.tz_minuteswest * 60 +
  285             (wall_cmos_clock ? adjkerntz : 0);
  286 
  287         if (timespeccmp(&ref, &ts, >)) {
  288                 diff = ref;
  289                 timespecsub(&ref, &ts);
  290         } else {
  291                 diff = ts;
  292                 timespecsub(&diff, &ref);
  293         }
  294         if (ts.tv_sec >= 2) {
  295                 /* badly off, adjust it */
  296                 tc_setclock(&ts);
  297         }
  298 }
  299 
  300 /*
  301  * Write system time back to RTC
  302  */
  303 void
  304 resettodr()
  305 {
  306         struct timespec ts;
  307         int error;
  308 
  309         if (disable_rtc_set || clock_dev == NULL)
  310                 return;
  311 
  312         getnanotime(&ts);
  313         ts.tv_sec -= tz.tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
  314         if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0) {
  315                 printf("warning: clock_settime failed (%d), time-of-day clock "
  316                     "not adjusted to system time\n", error);
  317                 return;
  318         }
  319 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_clock.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_clock.c
