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: releng/9.0/sys/kern/subr_rtc.c 211230 2010-08-12 17:17:05Z jkim $");
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 static struct timespec clock_adj;
66
67 /* XXX: should be kern. now, it's no longer machdep. */
68 static int disable_rtc_set;
69 SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set, CTLFLAG_RW, &disable_rtc_set,
70 0, "Disallow adjusting time-of-day clock");
71
72 void
73 clock_register(device_t dev, long res) /* res has units of microseconds */
74 {
75
76 if (clock_dev != NULL) {
77 if (clock_res > res) {
78 if (bootverbose)
79 device_printf(dev, "not installed as "
80 "time-of-day clock: clock %s has higher "
81 "resolution\n", device_get_name(clock_dev));
82 return;
83 }
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 clock_dev = dev;
90 clock_res = res;
91 clock_adj.tv_sec = res / 2 / 1000000;
92 clock_adj.tv_nsec = res / 2 % 1000000 * 1000;
93 if (bootverbose)
94 device_printf(dev, "registered as a time-of-day clock "
95 "(resolution %ldus, adjustment %jd.%09jds)\n", res,
96 (intmax_t)clock_adj.tv_sec, (intmax_t)clock_adj.tv_nsec);
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 ts;
113 int error;
114
115 if (clock_dev == NULL) {
116 printf("warning: no time-of-day clock registered, system time "
117 "will not be set accurately\n");
118 goto wrong_time;
119 }
120 /* XXX: We should poll all registered RTCs in case of failure */
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 goto wrong_time;
126 }
127 if (error == EINVAL || ts.tv_sec < 0) {
128 printf("Invalid time in real time clock.\n"
129 "Check and reset the date immediately!\n");
130 goto wrong_time;
131 }
132
133 ts.tv_sec += utc_offset();
134 timespecadd(&ts, &clock_adj);
135 tc_setclock(&ts);
136 return;
137
138 wrong_time:
139 if (base > 0) {
140 ts.tv_sec = base;
141 ts.tv_nsec = 0;
142 tc_setclock(&ts);
143 }
144 }
145
146 /*
147 * Write system time back to RTC
148 */
149 void
150 resettodr(void)
151 {
152 struct timespec ts;
153 int error;
154
155 if (disable_rtc_set || clock_dev == NULL)
156 return;
157
158 getnanotime(&ts);
159 timespecadd(&ts, &clock_adj);
160 ts.tv_sec -= utc_offset();
161 /* XXX: We should really set all registered RTCs */
162 if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0)
163 printf("warning: clock_settime failed (%d), time-of-day clock "
164 "not adjusted to system time\n", error);
165 }
Cache object: a7c6f9f5099c86c23fdf9b2f807a97ac
|