FreeBSD/Linux Kernel Cross Reference
sys/sys/clock.h
1 /*-
2 * Copyright (c) 1996 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Gordon W. Ross
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $NetBSD: clock_subr.h,v 1.7 2000/10/03 13:41:07 tsutsui Exp $
30 *
31 *
32 * This file is the central clearing-house for calendrical issues.
33 *
34 * In general the kernel does not know about minutes, hours, days, timezones,
35 * daylight savings time, leap-years and such. All that is theoretically a
36 * matter for userland only.
37 *
38 * Parts of kernel code does however care: badly designed filesystems store
39 * timestamps in local time and RTC chips sometimes track time in a local
40 * timezone instead of UTC and so on.
41 *
42 * All that code should go here for service.
43 *
44 * $FreeBSD$
45 */
46
47 #ifndef _SYS_CLOCK_H_
48 #define _SYS_CLOCK_H_
49
50 #ifdef _KERNEL /* No user serviceable parts */
51
52 /*
53 * Timezone info from settimeofday(2), usually not used
54 */
55 extern int tz_minuteswest;
56 extern int tz_dsttime;
57
58 int utc_offset(void);
59
60 /*
61 * Structure to hold the values typically reported by time-of-day clocks,
62 * expressed as binary integers (see below for a BCD version). This can be
63 * passed to the conversion functions to be converted to/from a struct timespec.
64 *
65 * On input, the year is interpreted as follows:
66 * 0 - 69 = 2000 - 2069
67 * 70 - 99 = 1970 - 1999
68 * 100 - 199 = 2000 - 2099 (Supports hardware "century bit".)
69 * 200 - 1969 = Invalid.
70 * 1970 - 9999 = Full 4-digit century+year.
71 *
72 * The dow field is ignored (not even validated) on input, but is always
73 * populated with day-of-week on output.
74 *
75 * clock_ct_to_ts() returns EINVAL if any values are out of range. The year
76 * field will always be 4-digit on output.
77 */
78 struct clocktime {
79 int year; /* year (4 digit year) */
80 int mon; /* month (1 - 12) */
81 int day; /* day (1 - 31) */
82 int hour; /* hour (0 - 23) */
83 int min; /* minute (0 - 59) */
84 int sec; /* second (0 - 59) */
85 int dow; /* day of week (0 - 6; 0 = Sunday) */
86 long nsec; /* nano seconds */
87 };
88
89 int clock_ct_to_ts(const struct clocktime *, struct timespec *);
90 void clock_ts_to_ct(const struct timespec *, struct clocktime *);
91
92 /*
93 * Structure to hold the values typically reported by time-of-day clocks,
94 * expressed as BCD. This can be passed to the conversion functions to be
95 * converted to/from a struct timespec.
96 *
97 * The clock_bcd_to_ts() function interprets the values in the year through sec
98 * fields as BCD numbers, and returns EINVAL if any BCD values are out of range.
99 * After conversion to binary, the values are passed to clock_ct_to_ts() and
100 * undergo further validation as described above. Year may be 2 or 4-digit BCD,
101 * interpreted as described above. The nsec field is binary. If the ampm arg
102 * is true, the incoming hour and ispm values are interpreted as 12-hour am/pm
103 * representation of the hour, otherwise hour is interpreted as 24-hour and ispm
104 * is ignored.
105 *
106 * The clock_ts_to_bcd() function converts the timespec to BCD values stored
107 * into year through sec. The value in year will be 4-digit BCD (e.g.,
108 * 0x2017). The mon through sec values will be 2-digit BCD. The nsec field will
109 * be binary, and the range of dow makes its binary and BCD values identical.
110 * If the ampm arg is true, the hour and ispm fields are set to the 12-hour
111 * time plus a pm flag, otherwise the hour is set to 24-hour time and ispm is
112 * set to false.
113 */
114 struct bcd_clocktime {
115 uint16_t year; /* year (2 or 4 digit year) */
116 uint8_t mon; /* month (1 - 12) */
117 uint8_t day; /* day (1 - 31) */
118 uint8_t hour; /* hour (0 - 23 or 1 - 12) */
119 uint8_t min; /* minute (0 - 59) */
120 uint8_t sec; /* second (0 - 59) */
121 uint8_t dow; /* day of week (0 - 6; 0 = Sunday) */
122 long nsec; /* nanoseconds */
123 bool ispm; /* true if hour represents pm time */
124 };
125
126 int clock_bcd_to_ts(const struct bcd_clocktime *, struct timespec *, bool ampm);
127 void clock_ts_to_bcd(const struct timespec *, struct bcd_clocktime *, bool ampm);
128
129 /*
130 * Time-of-day clock functions and flags. These functions might sleep.
131 *
132 * clock_register and clock_unregister() do what they say. Upon return from
133 * unregister, the clock's methods are not running and will not be called again.
134 *
135 * clock_schedule() requests that a registered clock's clock_settime() calls
136 * happen at the given offset into the second. The default is 0, meaning no
137 * specific scheduling. To schedule the call as soon after top-of-second as
138 * possible, specify 1. Each clock has its own schedule, but taskqueue_thread
139 * is shared by many tasks; the timing of the call is not guaranteed.
140 *
141 * Flags:
142 *
143 * CLOCKF_SETTIME_NO_TS
144 * Do not pass a timespec to clock_settime(), the driver obtains its own time
145 * and applies its own adjustments (this flag implies CLOCKF_SETTIME_NO_ADJ).
146 *
147 * CLOCKF_SETTIME_NO_ADJ
148 * Do not apply utc offset and resolution/accuracy adjustments to the value
149 * passed to clock_settime(), the driver applies them itself.
150 *
151 * CLOCKF_GETTIME_NO_ADJ
152 * Do not apply utc offset and resolution/accuracy adjustments to the value
153 * returned from clock_gettime(), the driver has already applied them.
154 */
155
156 #define CLOCKF_SETTIME_NO_TS 0x00000001
157 #define CLOCKF_SETTIME_NO_ADJ 0x00000002
158 #define CLOCKF_GETTIME_NO_ADJ 0x00000004
159
160 void clock_register(device_t _clockdev, long _resolution_us);
161 void clock_register_flags(device_t _clockdev, long _resolution_us, int _flags);
162 void clock_schedule(device_t clockdev, u_int _offsetns);
163 void clock_unregister(device_t _clockdev);
164
165 /*
166 * BCD to decimal and decimal to BCD.
167 */
168 #define FROMBCD(x) bcd2bin(x)
169 #define TOBCD(x) bin2bcd(x)
170
171 /* Some handy constants. */
172 #define SECDAY (24 * 60 * 60)
173 #define SECYR (SECDAY * 365)
174
175 /* Traditional POSIX base year */
176 #define POSIX_BASE_YEAR 1970
177
178 void timespec2fattime(const struct timespec *tsp, int utc, u_int16_t *ddp,
179 u_int16_t *dtp, u_int8_t *dhp);
180 void fattime2timespec(unsigned dd, unsigned dt, unsigned dh, int utc,
181 struct timespec *tsp);
182
183 /*
184 * Print a [bcd_]clocktime or timespec, optionally with fractional seconds. The
185 * nsdig argument can range from 0-9, and specifies how many decimal digits to
186 * display for fractional seconds.
187 */
188 void clock_print_bcd(const struct bcd_clocktime *bct, int nsdig);
189 void clock_print_ct(const struct clocktime *ct, int nsdig);
190 void clock_print_ts(const struct timespec *ts, int nsdig);
191
192 /*
193 * Debugging helpers for RTC clock drivers. Print a [bcd_]clocktime or
194 * timespec, only if rtc clock debugging has been enabled. The rw argument is
195 * one of CLOCK_DBG_READ or CLOCK_DBG_WRITE.
196 */
197 #define CLOCK_DBG_READ 0x01
198 #define CLOCK_DBG_WRITE 0x02
199 void clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct);
200 void clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct);
201 void clock_dbgprint_err(device_t dev, int rw, int err);
202 void clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts);
203
204 #endif /* _KERNEL */
205
206 #endif /* !_SYS_CLOCK_H_ */
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