FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_clock.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 * 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
45 /*
46 * Helpers for time-of-day clocks. This is useful for architectures that need
47 * support multiple models of such clocks, and generally serves to make the
48 * code more machine-independent.
49 * If the clock in question can also be used as a time counter, the driver
50 * needs to initiate this.
51 * This code is not yet used by all architectures.
52 */
53
54 /*
55 * Generic routines to convert between a POSIX date
56 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
57 * Derived from NetBSD arch/hp300/hp300/clock.c
58 */
59
60 #include <sys/cdefs.h>
61 __FBSDID("$FreeBSD: releng/5.2/sys/kern/subr_clock.c 116182 2003-06-11 00:56:59Z obrien $");
62
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/kernel.h>
66 #include <sys/bus.h>
67 #include <sys/clock.h>
68 #include <sys/sysctl.h>
69 #include <sys/timetc.h>
70
71 /* XXX: for the CPU_* sysctl OID constants. */
72 #include <machine/cpu.h>
73
74 #include "clock_if.h"
75
76 static __inline int leapyear(int year);
77 static int sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS);
78
79 #define FEBRUARY 2
80 #define days_in_year(y) (leapyear(y) ? 366 : 365)
81 #define days_in_month(y, m) \
82 (month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
83 /* Day of week. Days are counted from 1/1/1970, which was a Thursday */
84 #define day_of_week(days) (((days) + 4) % 7)
85
86 static const int month_days[12] = {
87 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
88 };
89
90 static device_t clock_dev = NULL;
91 static long clock_res;
92
93 int adjkerntz; /* local offset from GMT in seconds */
94 int disable_rtc_set; /* disable resettodr() if != 0 */
95 int wall_cmos_clock; /* wall CMOS clock assumed if != 0 */
96
97 /*
98 * These have traditionally been in machdep, but should probably be moved to
99 * kern.
100 */
101 SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
102 &adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
103
104 SYSCTL_INT(_machdep, CPU_DISRTCSET, disable_rtc_set,
105 CTLFLAG_RW, &disable_rtc_set, 0, "");
106
107 SYSCTL_INT(_machdep, CPU_WALLCLOCK, wall_cmos_clock,
108 CTLFLAG_RW, &wall_cmos_clock, 0, "");
109
110 static int
111 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
112 {
113 int error;
114 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
115 req);
116 if (!error && req->newptr)
117 resettodr();
118 return (error);
119 }
120
121 /*
122 * This inline avoids some unnecessary modulo operations
123 * as compared with the usual macro:
124 * ( ((year % 4) == 0 &&
125 * (year % 100) != 0) ||
126 * ((year % 400) == 0) )
127 * It is otherwise equivalent.
128 */
129 static __inline int
130 leapyear(int year)
131 {
132 int rv = 0;
133
134 if ((year & 3) == 0) {
135 rv = 1;
136 if ((year % 100) == 0) {
137 rv = 0;
138 if ((year % 400) == 0)
139 rv = 1;
140 }
141 }
142 return (rv);
143 }
144
145 int
146 clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
147 {
148 time_t secs;
149 int i, year, days;
150
151 year = ct->year;
152
153 /* Sanity checks. */
154 if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
155 ct->day > days_in_month(year, ct->mon) ||
156 ct->hour > 23 || ct->min > 59 || ct->sec > 59 ||
157 ct->year > 2037) /* time_t overflow */
158 return (EINVAL);
159
160 /*
161 * Compute days since start of time
162 * First from years, then from months.
163 */
164 days = 0;
165 for (i = POSIX_BASE_YEAR; i < year; i++)
166 days += days_in_year(i);
167
168 /* Months */
169 for (i = 1; i < ct->mon; i++)
170 days += days_in_month(year, i);
171 days += (ct->day - 1);
172
173 /* Another sanity check. */
174 if (ct->dow != -1 && ct->dow != day_of_week(days))
175 return (EINVAL);
176
177 /* Add hours, minutes, seconds. */
178 secs = ((days * 24 + ct->hour) * 60 + ct->min) * 60 + ct->sec;
179
180 ts->tv_sec = secs;
181 ts->tv_nsec = ct->nsec;
182 return (0);
183 }
184
185 void
186 clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
187 {
188 int i, year, days;
189 time_t rsec; /* remainder seconds */
190 time_t secs;
191
192 secs = ts->tv_sec;
193 days = secs / SECDAY;
194 rsec = secs % SECDAY;
195
196 ct->dow = day_of_week(days);
197
198 /* Subtract out whole years, counting them in i. */
199 for (year = POSIX_BASE_YEAR; days >= days_in_year(year); year++)
200 days -= days_in_year(year);
201 ct->year = year;
202
203 /* Subtract out whole months, counting them in i. */
204 for (i = 1; days >= days_in_month(year, i); i++)
205 days -= days_in_month(year, i);
206 ct->mon = i;
207
208 /* Days are what is left over (+1) from all that. */
209 ct->day = days + 1;
210
211 /* Hours, minutes, seconds are easy */
212 ct->hour = rsec / 3600;
213 rsec = rsec % 3600;
214 ct->min = rsec / 60;
215 rsec = rsec % 60;
216 ct->sec = rsec;
217 ct->nsec = ts->tv_nsec;
218 }
219
220 void
221 clock_register(device_t dev, long res)
222 {
223
224 if (clock_dev != NULL) {
225 if (clock_res > res) {
226 if (bootverbose) {
227 device_printf(dev, "not installed as "
228 "time-of-day clock: clock %s has higher "
229 "resolution\n", device_get_name(clock_dev));
230 }
231 return;
232 } else {
233 if (bootverbose) {
234 device_printf(clock_dev, "removed as "
235 "time-of-day clock: clock %s has higher "
236 "resolution\n", device_get_name(dev));
237 }
238 }
239 }
240 clock_dev = dev;
241 clock_res = res;
242 if (bootverbose) {
243 device_printf(dev, "registered as a time-of-day clock "
244 "(resolution %ldus)\n", res);
245 }
246 }
247
248 /*
249 * inittodr and settodr derived from the i386 versions written
250 * by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>, reintroduced and
251 * updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
252 */
253
254 /*
255 * Initialize the time of day register, based on the time base which is, e.g.
256 * from a filesystem.
257 */
258 void
259 inittodr(time_t base)
260 {
261 struct timespec diff, ref, ts;
262 int error;
263
264 if (base) {
265 ref.tv_sec = base;
266 ref.tv_nsec = 0;
267 tc_setclock(&ref);
268 }
269
270 if (clock_dev == NULL) {
271 printf("warning: no time-of-day clock registered, system time "
272 "will not be set accurately\n");
273 return;
274 }
275 error = CLOCK_GETTIME(clock_dev, &ts);
276 if (error != 0 && error != EINVAL) {
277 printf("warning: clock_gettime failed (%d), the system time "
278 "will not be set accurately\n", error);
279 return;
280 }
281 if (error == EINVAL || ts.tv_sec < 0) {
282 printf("Invalid time in real time clock.\n");
283 printf("Check and reset the date immediately!\n");
284 }
285
286 ts.tv_sec += tz_minuteswest * 60 +
287 (wall_cmos_clock ? adjkerntz : 0);
288
289 if (timespeccmp(&ref, &ts, >)) {
290 diff = ref;
291 timespecsub(&ref, &ts);
292 } else {
293 diff = ts;
294 timespecsub(&diff, &ref);
295 }
296 if (ts.tv_sec >= 2) {
297 /* badly off, adjust it */
298 tc_setclock(&ts);
299 }
300 }
301
302 /*
303 * Write system time back to RTC
304 */
305 void
306 resettodr()
307 {
308 struct timespec ts;
309 int error;
310
311 if (disable_rtc_set || clock_dev == NULL)
312 return;
313
314 getnanotime(&ts);
315 ts.tv_sec -= tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0);
316 if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0) {
317 printf("warning: clock_settime failed (%d), time-of-day clock "
318 "not adjusted to system time\n", error);
319 return;
320 }
321 }
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