sys/kern/subr_rtc.c

   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  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      from: Utah $Hdr: clock.c 1.18 91/01/21$
  35  *      from: @(#)clock.c       8.2 (Berkeley) 1/12/94
  36  *      from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
  37  *      and
  38  *      from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
  39  */
  40
  41 /*
  42  * Helpers for time-of-day clocks. This is useful for architectures that need
  43  * support multiple models of such clocks, and generally serves to make the
  44  * code more machine-independent.
  45  * If the clock in question can also be used as a time counter, the driver
  46  * needs to initiate this.
  47  * This code is not yet used by all architectures.
  48  */
  49
  50 #include <sys/cdefs.h>
  51 __FBSDID("$FreeBSD$");
  52
  53 #include <sys/param.h>
  54 #include <sys/systm.h>
  55 #include <sys/kernel.h>
  56 #include <sys/bus.h>
  57 #include <sys/clock.h>
  58 #include <sys/sysctl.h>
  59 #include <sys/timetc.h>
  60
  61 #include "clock_if.h"
  62
  63 static device_t clock_dev = NULL;
  64 static long clock_res;
  65
  66 /* XXX: should be kern. now, it's no longer machdep.  */
  67 static int disable_rtc_set;
  68 SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set,
  69         CTLFLAG_RW, &disable_rtc_set, 0, "");
  70
  71 void
  72 clock_register(device_t dev, long res)  /* res has units of microseconds */
  73 {
  74
  75         if (clock_dev != NULL) {
  76                 if (clock_res > res) {
  77                         if (bootverbose) {
  78                                 device_printf(dev, "not installed as "
  79                                     "time-of-day clock: clock %s has higher "
  80                                     "resolution\n", device_get_name(clock_dev));
  81                         }
  82                         return;
  83                 } else {
  84                         if (bootverbose) {
  85                                 device_printf(clock_dev, "removed as "
  86                                     "time-of-day clock: clock %s has higher "
  87                                     "resolution\n", device_get_name(dev));
  88                         }
  89                 }
  90         }
  91         clock_dev = dev;
  92         clock_res = res;
  93         if (bootverbose) {
  94                 device_printf(dev, "registered as a time-of-day clock "
  95                     "(resolution %ldus)\n", res);
  96         }
  97 }
  98
  99 /*
 100  * inittodr and settodr derived from the i386 versions written
 101  * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>,  reintroduced and
 102  * updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
 103  */
 104
 105 /*
 106  * Initialize the time of day register, based on the time base which is, e.g.
 107  * from a filesystem.
 108  */
 109 void
 110 inittodr(time_t base)
 111 {
 112         struct timespec diff, ref, ts;
 113         int error;
 114
 115         if (base) {
 116                 ref.tv_sec = base;
 117                 ref.tv_nsec = 0;
 118                 tc_setclock(&ref);
 119         }
 120
 121         if (clock_dev == NULL) {
 122                 printf("warning: no time-of-day clock registered, system time "
 123                     "will not be set accurately\n");
 124                 return;
 125         }
 126         /* XXX: We should poll all registered RTCs in case of failure */
 127         error = CLOCK_GETTIME(clock_dev, &ts);
 128         if (error != 0 && error != EINVAL) {
 129                 printf("warning: clock_gettime failed (%d), the system time "
 130                     "will not be set accurately\n", error);
 131                 return;
 132         }
 133         if (error == EINVAL || ts.tv_sec < 0) {
 134                 printf("Invalid time in real time clock.\n");
 135                 printf("Check and reset the date immediately!\n");
 136         }
 137
 138         ts.tv_sec += utc_offset();
 139
 140         if (timespeccmp(&ref, &ts, >)) {
 141                 diff = ref;
 142                 timespecsub(&ref, &ts);
 143         } else {
 144                 diff = ts;
 145                 timespecsub(&diff, &ref);
 146         }
 147         if (ts.tv_sec >= 2) {
 148                 /* badly off, adjust it */
 149                 tc_setclock(&ts);
 150         }
 151 }
 152
 153 /*
 154  * Write system time back to RTC
 155  */
 156 void
 157 resettodr()
 158 {
 159         struct timespec ts;
 160         int error;
 161
 162         if (disable_rtc_set || clock_dev == NULL)
 163                 return;
 164
 165         getnanotime(&ts);
 166         ts.tv_sec -= utc_offset();
 167         /* XXX: We should really set all registered RTCs */
 168         if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0) {
 169                 printf("warning: clock_settime failed (%d), time-of-day clock "
 170                     "not adjusted to system time\n", error);
 171                 return;
 172         }
 173 }