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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*****************************************************************************
2 * *
3 * Copyright (c) David L. Mills 1993 *
4 * *
5 * Permission to use, copy, modify, and distribute this software and its *
6 * documentation for any purpose and without fee is hereby granted, provided *
7 * that the above copyright notice appears in all copies and that both the *
8 * copyright notice and this permission notice appear in supporting *
9 * documentation, and that the name University of Delaware not be used in *
10 * advertising or publicity pertaining to distribution of the software *
11 * without specific, written prior permission. The University of Delaware *
12 * makes no representations about the suitability this software for any *
13 * purpose. It is provided "as is" without express or implied warranty. *
14 * *
15 *****************************************************************************/
16
17/*
18 * Modification history timex.h
19 *
20 * 29 Dec 97 Russell King
21 * Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
22 * for ARM machines
23 *
24 * 9 Jan 97 Adrian Sun
25 * Shifted LATCH define to allow access to alpha machines.
26 *
27 * 26 Sep 94 David L. Mills
28 * Added defines for hybrid phase/frequency-lock loop.
29 *
30 * 19 Mar 94 David L. Mills
31 * Moved defines from kernel routines to header file and added new
32 * defines for PPS phase-lock loop.
33 *
34 * 20 Feb 94 David L. Mills
35 * Revised status codes and structures for external clock and PPS
36 * signal discipline.
37 *
38 * 28 Nov 93 David L. Mills
39 * Adjusted parameters to improve stability and increase poll
40 * interval.
41 *
42 * 17 Sep 93 David L. Mills
43 * Created file $NTP/include/sys/timex.h
44 * 07 Oct 93 Torsten Duwe
45 * Derived linux/timex.h
46 * 1995-08-13 Torsten Duwe
47 * kernel PLL updated to 1994-12-13 specs (rfc-1589)
48 * 1997-08-30 Ulrich Windl
49 * Added new constant NTP_PHASE_LIMIT
50 * 2004-08-12 Christoph Lameter
51 * Reworked time interpolation logic
52 */
53#ifndef _LINUX_TIMEX_H
54#define _LINUX_TIMEX_H
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#include <linux/time.h>
57
Roman Zippeleea83d82008-05-01 04:34:33 -070058#define NTP_API 4 /* NTP API version */
59
Linus Torvalds1da177e2005-04-16 15:20:36 -070060/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 * syscall interface - used (mainly by NTP daemon)
62 * to discipline kernel clock oscillator
63 */
64struct timex {
65 unsigned int modes; /* mode selector */
66 long offset; /* time offset (usec) */
67 long freq; /* frequency offset (scaled ppm) */
68 long maxerror; /* maximum error (usec) */
69 long esterror; /* estimated error (usec) */
70 int status; /* clock command/status */
71 long constant; /* pll time constant */
72 long precision; /* clock precision (usec) (read only) */
73 long tolerance; /* clock frequency tolerance (ppm)
74 * (read only)
75 */
Richard Cochran094aa182011-02-01 13:52:20 +000076 struct timeval time; /* (read only, except for ADJ_SETOFFSET) */
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 long tick; /* (modified) usecs between clock ticks */
78
79 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
80 long jitter; /* pps jitter (us) (ro) */
81 int shift; /* interval duration (s) (shift) (ro) */
82 long stabil; /* pps stability (scaled ppm) (ro) */
83 long jitcnt; /* jitter limit exceeded (ro) */
84 long calcnt; /* calibration intervals (ro) */
85 long errcnt; /* calibration errors (ro) */
86 long stbcnt; /* stability limit exceeded (ro) */
87
Roman Zippel153b5d02008-05-01 04:34:37 -070088 int tai; /* TAI offset (ro) */
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 int :32; int :32; int :32; int :32;
91 int :32; int :32; int :32; int :32;
Roman Zippel153b5d02008-05-01 04:34:37 -070092 int :32; int :32; int :32;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093};
94
95/*
96 * Mode codes (timex.mode)
97 */
98#define ADJ_OFFSET 0x0001 /* time offset */
99#define ADJ_FREQUENCY 0x0002 /* frequency offset */
100#define ADJ_MAXERROR 0x0004 /* maximum time error */
101#define ADJ_ESTERROR 0x0008 /* estimated time error */
102#define ADJ_STATUS 0x0010 /* clock status */
103#define ADJ_TIMECONST 0x0020 /* pll time constant */
Roman Zippel153b5d02008-05-01 04:34:37 -0700104#define ADJ_TAI 0x0080 /* set TAI offset */
Richard Cochran094aa182011-02-01 13:52:20 +0000105#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
Roman Zippeleea83d82008-05-01 04:34:33 -0700106#define ADJ_MICRO 0x1000 /* select microsecond resolution */
107#define ADJ_NANO 0x2000 /* select nanosecond resolution */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108#define ADJ_TICK 0x4000 /* tick value */
Roman Zippel916c7a82008-08-20 16:46:08 -0700109
110#ifdef __KERNEL__
111#define ADJ_ADJTIME 0x8000 /* switch between adjtime/adjtimex modes */
112#define ADJ_OFFSET_SINGLESHOT 0x0001 /* old-fashioned adjtime */
113#define ADJ_OFFSET_READONLY 0x2000 /* read-only adjtime */
114#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
Roman Zippel916c7a82008-08-20 16:46:08 -0700116#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
117#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
john stultzc95b4502009-08-27 17:04:42 -0700119/* NTP userland likes the MOD_ prefix better */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120#define MOD_OFFSET ADJ_OFFSET
121#define MOD_FREQUENCY ADJ_FREQUENCY
122#define MOD_MAXERROR ADJ_MAXERROR
123#define MOD_ESTERROR ADJ_ESTERROR
124#define MOD_STATUS ADJ_STATUS
125#define MOD_TIMECONST ADJ_TIMECONST
john stultzc95b4502009-08-27 17:04:42 -0700126#define MOD_TAI ADJ_TAI
127#define MOD_MICRO ADJ_MICRO
128#define MOD_NANO ADJ_NANO
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
130
131/*
132 * Status codes (timex.status)
133 */
134#define STA_PLL 0x0001 /* enable PLL updates (rw) */
135#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
136#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
137#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
138
139#define STA_INS 0x0010 /* insert leap (rw) */
140#define STA_DEL 0x0020 /* delete leap (rw) */
141#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
142#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
143
144#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
145#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
146#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
147#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
148
149#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
Roman Zippeleea83d82008-05-01 04:34:33 -0700150#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
151#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
152#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Roman Zippeleea83d82008-05-01 04:34:33 -0700154/* read-only bits */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
Roman Zippeleea83d82008-05-01 04:34:33 -0700156 STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
158/*
159 * Clock states (time_state)
160 */
161#define TIME_OK 0 /* clock synchronized, no leap second */
162#define TIME_INS 1 /* insert leap second */
163#define TIME_DEL 2 /* delete leap second */
164#define TIME_OOP 3 /* leap second in progress */
165#define TIME_WAIT 4 /* leap second has occurred */
166#define TIME_ERROR 5 /* clock not synchronized */
167#define TIME_BAD TIME_ERROR /* bw compat */
168
169#ifdef __KERNEL__
Mike Frysingerc29541b2008-12-01 14:18:11 -0800170#include <linux/compiler.h>
171#include <linux/types.h>
172#include <linux/param.h>
173
David Woodhouseee6baf82006-09-12 20:36:03 -0700174#include <asm/timex.h>
175
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176/*
john stultz22cfbbf2009-05-06 11:43:57 +0200177 * SHIFT_PLL is used as a dampening factor to define how much we
178 * adjust the frequency correction for a given offset in PLL mode.
179 * It also used in dampening the offset correction, to define how
180 * much of the current value in time_offset we correct for each
181 * second. Changing this value changes the stiffness of the ntp
182 * adjustment code. A lower value makes it more flexible, reducing
183 * NTP convergence time. A higher value makes it stiffer, increasing
184 * convergence time, but making the clock more stable.
Mike Frysingerc29541b2008-12-01 14:18:11 -0800185 *
john stultze13cf6e2009-05-11 18:13:13 -0700186 * In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
john stultz22cfbbf2009-05-06 11:43:57 +0200187 * However this seems to increase convergence time much too long.
188 *
189 * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
190 *
191 * In the above mailing list discussion, it seems the value of 4
192 * was appropriate for other Unix systems with HZ=100, and that
193 * SHIFT_PLL should be decreased as HZ increases. However, Linux's
194 * clock steering implementation is HZ independent.
195 *
196 * Through experimentation, a SHIFT_PLL value of 2 was found to allow
197 * for fast convergence (very similar to the NTPv3 code used prior to
198 * v2.6.19), with good clock stability.
199 *
200 *
201 * SHIFT_FLL is used as a dampening factor to define how much we
202 * adjust the frequency correction for a given offset in FLL mode.
john stultze13cf6e2009-05-11 18:13:13 -0700203 * In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
john stultz22cfbbf2009-05-06 11:43:57 +0200204 *
205 * MAXTC establishes the maximum time constant of the PLL.
Mike Frysingerc29541b2008-12-01 14:18:11 -0800206 */
john stultz22cfbbf2009-05-06 11:43:57 +0200207#define SHIFT_PLL 2 /* PLL frequency factor (shift) */
Mike Frysingerc29541b2008-12-01 14:18:11 -0800208#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
209#define MAXTC 10 /* maximum time constant (shift) */
210
211/*
212 * SHIFT_USEC defines the scaling (shift) of the time_freq and
213 * time_tolerance variables, which represent the current frequency
214 * offset and maximum frequency tolerance.
215 */
216#define SHIFT_USEC 16 /* frequency offset scale (shift) */
Ingo Molnar2b9d1492009-02-22 15:48:43 +0100217#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
Mike Frysingerc29541b2008-12-01 14:18:11 -0800218#define PPM_SCALE_INV_SHIFT 19
john stultz22cfbbf2009-05-06 11:43:57 +0200219#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
Mike Frysingerc29541b2008-12-01 14:18:11 -0800220 PPM_SCALE + 1)
221
john stultz22cfbbf2009-05-06 11:43:57 +0200222#define MAXPHASE 500000000L /* max phase error (ns) */
Mike Frysingerc29541b2008-12-01 14:18:11 -0800223#define MAXFREQ 500000 /* max frequency error (ns/s) */
224#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
225#define MINSEC 256 /* min interval between updates (s) */
226#define MAXSEC 2048 /* max interval between updates (s) */
227#define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */
228
229/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 * kernel variables
231 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
232 * estimated error = NTP dispersion.
233 */
234extern unsigned long tick_usec; /* USER_HZ period (usec) */
235extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Roman Zippel7dffa3c2008-05-01 04:34:41 -0700237extern void ntp_init(void);
Roman Zippelb0ee7552006-09-30 23:28:22 -0700238extern void ntp_clear(void);
john stultzb149ee22005-09-06 15:17:46 -0700239
john stultz1bb34a42005-10-30 15:01:42 -0800240/* Required to safely shift negative values */
241#define shift_right(x, s) ({ \
242 __typeof__(x) __x = (x); \
243 __typeof__(s) __s = (s); \
244 __x < 0 ? -(-__x >> __s) : __x >> __s; \
245})
246
Roman Zippel7fc5c782008-05-01 04:34:38 -0700247#define NTP_SCALE_SHIFT 32
Roman Zippel19923c12006-06-26 00:25:18 -0700248
john stultzf4304ab2007-02-16 01:27:26 -0800249#define NTP_INTERVAL_FREQ (HZ)
Roman Zippel10a398d2008-03-04 15:14:26 -0800250#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
john stultzf4304ab2007-02-16 01:27:26 -0800251
Roman Zippel8383c422008-05-01 04:34:39 -0700252/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
John Stultzea7cf492011-11-14 13:18:07 -0800253extern u64 ntp_tick_length(void);
Paul Mackerras726c14b2006-02-17 10:30:23 +1100254
john stultz4c7ee8d2006-09-30 23:28:22 -0700255extern void second_overflow(void);
Stephen Rothwell3158e942006-03-26 01:37:29 -0800256extern int do_adjtimex(struct timex *);
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800257extern void hardpps(const struct timespec *, const struct timespec *);
Stephen Rothwell3158e942006-03-26 01:37:29 -0800258
Andrew Morton941e4922008-02-06 01:36:42 -0800259int read_current_timer(unsigned long *timer_val);
260
Arnd Bergmann08604bd2009-06-16 15:31:12 -0700261/* The clock frequency of the i8253/i8254 PIT */
262#define PIT_TICK_RATE 1193182ul
263
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264#endif /* KERNEL */
265
266#endif /* LINUX_TIMEX_H */