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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 */
76 struct timeval time; /* (read only) */
77 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 */
Roman Zippeleea83d82008-05-01 04:34:33 -0700105#define ADJ_MICRO 0x1000 /* select microsecond resolution */
106#define ADJ_NANO 0x2000 /* select nanosecond resolution */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107#define ADJ_TICK 0x4000 /* tick value */
Roman Zippel916c7a82008-08-20 16:46:08 -0700108
109#ifdef __KERNEL__
110#define ADJ_ADJTIME 0x8000 /* switch between adjtime/adjtimex modes */
111#define ADJ_OFFSET_SINGLESHOT 0x0001 /* old-fashioned adjtime */
112#define ADJ_OFFSET_READONLY 0x2000 /* read-only adjtime */
113#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
Roman Zippel916c7a82008-08-20 16:46:08 -0700115#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
116#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
john stultzc95b4502009-08-27 17:04:42 -0700118/* NTP userland likes the MOD_ prefix better */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119#define MOD_OFFSET ADJ_OFFSET
120#define MOD_FREQUENCY ADJ_FREQUENCY
121#define MOD_MAXERROR ADJ_MAXERROR
122#define MOD_ESTERROR ADJ_ESTERROR
123#define MOD_STATUS ADJ_STATUS
124#define MOD_TIMECONST ADJ_TIMECONST
john stultzc95b4502009-08-27 17:04:42 -0700125#define MOD_TAI ADJ_TAI
126#define MOD_MICRO ADJ_MICRO
127#define MOD_NANO ADJ_NANO
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129
130/*
131 * Status codes (timex.status)
132 */
133#define STA_PLL 0x0001 /* enable PLL updates (rw) */
134#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
135#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
136#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
137
138#define STA_INS 0x0010 /* insert leap (rw) */
139#define STA_DEL 0x0020 /* delete leap (rw) */
140#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
141#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
142
143#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
144#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
145#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
146#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
147
148#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
Roman Zippeleea83d82008-05-01 04:34:33 -0700149#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
150#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
151#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Roman Zippeleea83d82008-05-01 04:34:33 -0700153/* read-only bits */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
Roman Zippeleea83d82008-05-01 04:34:33 -0700155 STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
157/*
158 * Clock states (time_state)
159 */
160#define TIME_OK 0 /* clock synchronized, no leap second */
161#define TIME_INS 1 /* insert leap second */
162#define TIME_DEL 2 /* delete leap second */
163#define TIME_OOP 3 /* leap second in progress */
164#define TIME_WAIT 4 /* leap second has occurred */
165#define TIME_ERROR 5 /* clock not synchronized */
166#define TIME_BAD TIME_ERROR /* bw compat */
167
168#ifdef __KERNEL__
Mike Frysingerc29541b2008-12-01 14:18:11 -0800169#include <linux/compiler.h>
170#include <linux/types.h>
171#include <linux/param.h>
172
David Woodhouseee6baf82006-09-12 20:36:03 -0700173#include <asm/timex.h>
174
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175/*
john stultz22cfbbf2009-05-06 11:43:57 +0200176 * SHIFT_PLL is used as a dampening factor to define how much we
177 * adjust the frequency correction for a given offset in PLL mode.
178 * It also used in dampening the offset correction, to define how
179 * much of the current value in time_offset we correct for each
180 * second. Changing this value changes the stiffness of the ntp
181 * adjustment code. A lower value makes it more flexible, reducing
182 * NTP convergence time. A higher value makes it stiffer, increasing
183 * convergence time, but making the clock more stable.
Mike Frysingerc29541b2008-12-01 14:18:11 -0800184 *
john stultze13cf6e2009-05-11 18:13:13 -0700185 * In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
john stultz22cfbbf2009-05-06 11:43:57 +0200186 * However this seems to increase convergence time much too long.
187 *
188 * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
189 *
190 * In the above mailing list discussion, it seems the value of 4
191 * was appropriate for other Unix systems with HZ=100, and that
192 * SHIFT_PLL should be decreased as HZ increases. However, Linux's
193 * clock steering implementation is HZ independent.
194 *
195 * Through experimentation, a SHIFT_PLL value of 2 was found to allow
196 * for fast convergence (very similar to the NTPv3 code used prior to
197 * v2.6.19), with good clock stability.
198 *
199 *
200 * SHIFT_FLL is used as a dampening factor to define how much we
201 * adjust the frequency correction for a given offset in FLL mode.
john stultze13cf6e2009-05-11 18:13:13 -0700202 * In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
john stultz22cfbbf2009-05-06 11:43:57 +0200203 *
204 * MAXTC establishes the maximum time constant of the PLL.
Mike Frysingerc29541b2008-12-01 14:18:11 -0800205 */
john stultz22cfbbf2009-05-06 11:43:57 +0200206#define SHIFT_PLL 2 /* PLL frequency factor (shift) */
Mike Frysingerc29541b2008-12-01 14:18:11 -0800207#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
208#define MAXTC 10 /* maximum time constant (shift) */
209
210/*
211 * SHIFT_USEC defines the scaling (shift) of the time_freq and
212 * time_tolerance variables, which represent the current frequency
213 * offset and maximum frequency tolerance.
214 */
215#define SHIFT_USEC 16 /* frequency offset scale (shift) */
Ingo Molnar2b9d1492009-02-22 15:48:43 +0100216#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
Mike Frysingerc29541b2008-12-01 14:18:11 -0800217#define PPM_SCALE_INV_SHIFT 19
john stultz22cfbbf2009-05-06 11:43:57 +0200218#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
Mike Frysingerc29541b2008-12-01 14:18:11 -0800219 PPM_SCALE + 1)
220
john stultz22cfbbf2009-05-06 11:43:57 +0200221#define MAXPHASE 500000000L /* max phase error (ns) */
Mike Frysingerc29541b2008-12-01 14:18:11 -0800222#define MAXFREQ 500000 /* max frequency error (ns/s) */
223#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
224#define MINSEC 256 /* min interval between updates (s) */
225#define MAXSEC 2048 /* max interval between updates (s) */
226#define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */
227
228/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 * kernel variables
230 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
231 * estimated error = NTP dispersion.
232 */
233extern unsigned long tick_usec; /* USER_HZ period (usec) */
234extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
235extern int tickadj; /* amount of adjustment per tick */
236
237/*
238 * phase-lock loop variables
239 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240extern int time_status; /* clock synchronization status bits */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241extern long time_maxerror; /* maximum error */
242extern long time_esterror; /* estimated error */
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244extern long time_adjust; /* The amount of adjtime left */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
Roman Zippel7dffa3c2008-05-01 04:34:41 -0700246extern void ntp_init(void);
Roman Zippelb0ee7552006-09-30 23:28:22 -0700247extern void ntp_clear(void);
john stultzb149ee22005-09-06 15:17:46 -0700248
249/**
250 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
251 *
252 */
253static inline int ntp_synced(void)
254{
255 return !(time_status & STA_UNSYNC);
256}
257
john stultz1bb34a42005-10-30 15:01:42 -0800258/* Required to safely shift negative values */
259#define shift_right(x, s) ({ \
260 __typeof__(x) __x = (x); \
261 __typeof__(s) __s = (s); \
262 __x < 0 ? -(-__x >> __s) : __x >> __s; \
263})
264
Roman Zippel7fc5c782008-05-01 04:34:38 -0700265#define NTP_SCALE_SHIFT 32
Roman Zippel19923c12006-06-26 00:25:18 -0700266
john stultzf4304ab2007-02-16 01:27:26 -0800267#define NTP_INTERVAL_FREQ (HZ)
Roman Zippel10a398d2008-03-04 15:14:26 -0800268#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
john stultzf4304ab2007-02-16 01:27:26 -0800269
Roman Zippel8383c422008-05-01 04:34:39 -0700270/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
271extern u64 tick_length;
Paul Mackerras726c14b2006-02-17 10:30:23 +1100272
john stultz4c7ee8d2006-09-30 23:28:22 -0700273extern void second_overflow(void);
274extern void update_ntp_one_tick(void);
Stephen Rothwell3158e942006-03-26 01:37:29 -0800275extern int do_adjtimex(struct timex *);
276
Roman Zippel7236e972006-10-06 00:43:54 -0700277/* Don't use! Compatibility define for existing users. */
278#define tickadj (500/HZ ? : 1)
279
Andrew Morton941e4922008-02-06 01:36:42 -0800280int read_current_timer(unsigned long *timer_val);
281
Arnd Bergmann08604bd2009-06-16 15:31:12 -0700282/* The clock frequency of the i8253/i8254 PIT */
283#define PIT_TICK_RATE 1193182ul
284
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285#endif /* KERNEL */
286
287#endif /* LINUX_TIMEX_H */