FreeBSD/Linux Kernel Cross Reference
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 void
67 clock_register(device_t dev, long res) /* res has units of microseconds */
68 {
69
70 if (clock_dev != NULL) {
71 if (clock_res > res) {
72 if (bootverbose) {
73 device_printf(dev, "not installed as "
74 "time-of-day clock: clock %s has higher "
75 "resolution\n", device_get_name(clock_dev));
76 }
77 return;
78 } else {
79 if (bootverbose) {
80 device_printf(clock_dev, "removed as "
81 "time-of-day clock: clock %s has higher "
82 "resolution\n", device_get_name(dev));
83 }
84 }
85 }
86 clock_dev = dev;
87 clock_res = res;
88 if (bootverbose) {
89 device_printf(dev, "registered as a time-of-day clock "
90 "(resolution %ldus)\n", res);
91 }
92 }
93
94 /*
95 * inittodr and settodr derived from the i386 versions written
96 * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>, reintroduced and
97 * updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
98 */
99
100 /*
101 * Initialize the time of day register, based on the time base which is, e.g.
102 * from a filesystem.
103 */
104 void
105 inittodr(time_t base)
106 {
107 struct timespec diff, ref, ts;
108 int error;
109
110 if (base) {
111 ref.tv_sec = base;
112 ref.tv_nsec = 0;
113 tc_setclock(&ref);
114 }
115
116 if (clock_dev == NULL) {
117 printf("warning: no time-of-day clock registered, system time "
118 "will not be set accurately\n");
119 return;
120 }
121 error = CLOCK_GETTIME(clock_dev, &ts);
122 if (error != 0 && error != EINVAL) {
123 printf("warning: clock_gettime failed (%d), the system time "
124 "will not be set accurately\n", error);
125 return;
126 }
127 if (error == EINVAL || ts.tv_sec < 0) {
128 printf("Invalid time in real time clock.\n");
129 printf("Check and reset the date immediately!\n");
130 }
131
132 ts.tv_sec += utc_offset();
133
134 if (timespeccmp(&ref, &ts, >)) {
135 diff = ref;
136 timespecsub(&ref, &ts);
137 } else {
138 diff = ts;
139 timespecsub(&diff, &ref);
140 }
141 if (ts.tv_sec >= 2) {
142 /* badly off, adjust it */
143 tc_setclock(&ts);
144 }
145 }
146
147 /*
148 * Write system time back to RTC
149 */
150 void
151 resettodr()
152 {
153 struct timespec ts;
154 int error;
155
156 if (disable_rtc_set || clock_dev == NULL)
157 return;
158
159 getnanotime(&ts);
160 ts.tv_sec -= utc_offset();
161 if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0) {
162 printf("warning: clock_settime failed (%d), time-of-day clock "
163 "not adjusted to system time\n", error);
164 return;
165 }
166 }
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