Linux kernel mirror (for testing)
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1/*****************************************************************************
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
56#include <linux/compiler.h>
57#include <linux/time.h>
58
59#include <asm/param.h>
60
61/*
62 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
63 * for a slightly underdamped convergence characteristic. SHIFT_KH
64 * establishes the damping of the FLL and is chosen by wisdom and black
65 * art.
66 *
67 * MAXTC establishes the maximum time constant of the PLL. With the
68 * SHIFT_KG and SHIFT_KF values given and a time constant range from
69 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
70 * respectively.
71 */
72#define SHIFT_PLL 4 /* PLL frequency factor (shift) */
73#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
74#define MAXTC 10 /* maximum time constant (shift) */
75
76/*
77 * The SHIFT_UPDATE define establishes the decimal point of the
78 * time_offset variable which represents the current offset with
79 * respect to standard time.
80 *
81 * SHIFT_USEC defines the scaling (shift) of the time_freq and
82 * time_tolerance variables, which represent the current frequency
83 * offset and maximum frequency tolerance.
84 */
85#define SHIFT_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */
86#define SHIFT_USEC 16 /* frequency offset scale (shift) */
87#define SHIFT_NSEC 12 /* kernel frequency offset scale */
88
89#define MAXPHASE 512000L /* max phase error (us) */
90#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
91#define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */
92#define MINSEC 256 /* min interval between updates (s) */
93#define MAXSEC 2048 /* max interval between updates (s) */
94#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
95
96/*
97 * syscall interface - used (mainly by NTP daemon)
98 * to discipline kernel clock oscillator
99 */
100struct timex {
101 unsigned int modes; /* mode selector */
102 long offset; /* time offset (usec) */
103 long freq; /* frequency offset (scaled ppm) */
104 long maxerror; /* maximum error (usec) */
105 long esterror; /* estimated error (usec) */
106 int status; /* clock command/status */
107 long constant; /* pll time constant */
108 long precision; /* clock precision (usec) (read only) */
109 long tolerance; /* clock frequency tolerance (ppm)
110 * (read only)
111 */
112 struct timeval time; /* (read only) */
113 long tick; /* (modified) usecs between clock ticks */
114
115 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
116 long jitter; /* pps jitter (us) (ro) */
117 int shift; /* interval duration (s) (shift) (ro) */
118 long stabil; /* pps stability (scaled ppm) (ro) */
119 long jitcnt; /* jitter limit exceeded (ro) */
120 long calcnt; /* calibration intervals (ro) */
121 long errcnt; /* calibration errors (ro) */
122 long stbcnt; /* stability limit exceeded (ro) */
123
124 int :32; int :32; int :32; int :32;
125 int :32; int :32; int :32; int :32;
126 int :32; int :32; int :32; int :32;
127};
128
129/*
130 * Mode codes (timex.mode)
131 */
132#define ADJ_OFFSET 0x0001 /* time offset */
133#define ADJ_FREQUENCY 0x0002 /* frequency offset */
134#define ADJ_MAXERROR 0x0004 /* maximum time error */
135#define ADJ_ESTERROR 0x0008 /* estimated time error */
136#define ADJ_STATUS 0x0010 /* clock status */
137#define ADJ_TIMECONST 0x0020 /* pll time constant */
138#define ADJ_TICK 0x4000 /* tick value */
139#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
140
141/* xntp 3.4 compatibility names */
142#define MOD_OFFSET ADJ_OFFSET
143#define MOD_FREQUENCY ADJ_FREQUENCY
144#define MOD_MAXERROR ADJ_MAXERROR
145#define MOD_ESTERROR ADJ_ESTERROR
146#define MOD_STATUS ADJ_STATUS
147#define MOD_TIMECONST ADJ_TIMECONST
148#define MOD_CLKB ADJ_TICK
149#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
150
151
152/*
153 * Status codes (timex.status)
154 */
155#define STA_PLL 0x0001 /* enable PLL updates (rw) */
156#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
157#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
158#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
159
160#define STA_INS 0x0010 /* insert leap (rw) */
161#define STA_DEL 0x0020 /* delete leap (rw) */
162#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
163#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
164
165#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
166#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
167#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
168#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
169
170#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
171
172#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
173 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
174
175/*
176 * Clock states (time_state)
177 */
178#define TIME_OK 0 /* clock synchronized, no leap second */
179#define TIME_INS 1 /* insert leap second */
180#define TIME_DEL 2 /* delete leap second */
181#define TIME_OOP 3 /* leap second in progress */
182#define TIME_WAIT 4 /* leap second has occurred */
183#define TIME_ERROR 5 /* clock not synchronized */
184#define TIME_BAD TIME_ERROR /* bw compat */
185
186#ifdef __KERNEL__
187#include <asm/timex.h>
188
189/*
190 * kernel variables
191 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
192 * estimated error = NTP dispersion.
193 */
194extern unsigned long tick_usec; /* USER_HZ period (usec) */
195extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
196extern int tickadj; /* amount of adjustment per tick */
197
198/*
199 * phase-lock loop variables
200 */
201extern int time_status; /* clock synchronization status bits */
202extern long time_maxerror; /* maximum error */
203extern long time_esterror; /* estimated error */
204
205extern long time_freq; /* frequency offset (scaled ppm) */
206
207extern long time_adjust; /* The amount of adjtime left */
208
209extern void ntp_clear(void);
210
211/**
212 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
213 *
214 */
215static inline int ntp_synced(void)
216{
217 return !(time_status & STA_UNSYNC);
218}
219
220/* Required to safely shift negative values */
221#define shift_right(x, s) ({ \
222 __typeof__(x) __x = (x); \
223 __typeof__(s) __s = (s); \
224 __x < 0 ? -(-__x >> __s) : __x >> __s; \
225})
226
227
228#ifdef CONFIG_TIME_INTERPOLATION
229
230#define TIME_SOURCE_CPU 0
231#define TIME_SOURCE_MMIO64 1
232#define TIME_SOURCE_MMIO32 2
233#define TIME_SOURCE_FUNCTION 3
234
235/* For proper operations time_interpolator clocks must run slightly slower
236 * than the standard clock since the interpolator may only correct by having
237 * time jump forward during a tick. A slower clock is usually a side effect
238 * of the integer divide of the nanoseconds in a second by the frequency.
239 * The accuracy of the division can be increased by specifying a shift.
240 * However, this may cause the clock not to be slow enough.
241 * The interpolator will self-tune the clock by slowing down if no
242 * resets occur or speeding up if the time jumps per analysis cycle
243 * become too high.
244 *
245 * Setting jitter compensates for a fluctuating timesource by comparing
246 * to the last value read from the timesource to insure that an earlier value
247 * is not returned by a later call. The price to pay
248 * for the compensation is that the timer routines are not as scalable anymore.
249 */
250
251struct time_interpolator {
252 u16 source; /* time source flags */
253 u8 shift; /* increases accuracy of multiply by shifting. */
254 /* Note that bits may be lost if shift is set too high */
255 u8 jitter; /* if set compensate for fluctuations */
256 u32 nsec_per_cyc; /* set by register_time_interpolator() */
257 void *addr; /* address of counter or function */
258 cycles_t mask; /* mask the valid bits of the counter */
259 unsigned long offset; /* nsec offset at last update of interpolator */
260 u64 last_counter; /* counter value in units of the counter at last update */
261 cycles_t last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */
262 u64 frequency; /* frequency in counts/second */
263 long drift; /* drift in parts-per-million (or -1) */
264 unsigned long skips; /* skips forward */
265 unsigned long ns_skipped; /* nanoseconds skipped */
266 struct time_interpolator *next;
267};
268
269extern void register_time_interpolator(struct time_interpolator *);
270extern void unregister_time_interpolator(struct time_interpolator *);
271extern void time_interpolator_reset(void);
272extern unsigned long time_interpolator_get_offset(void);
273extern void time_interpolator_update(long delta_nsec);
274
275#else /* !CONFIG_TIME_INTERPOLATION */
276
277static inline void time_interpolator_reset(void)
278{
279}
280
281static inline void time_interpolator_update(long delta_nsec)
282{
283}
284
285#endif /* !CONFIG_TIME_INTERPOLATION */
286
287#define TICK_LENGTH_SHIFT 32
288
289#ifdef CONFIG_NO_HZ
290#define NTP_INTERVAL_FREQ (2)
291#else
292#define NTP_INTERVAL_FREQ (HZ)
293#endif
294#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
295
296/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
297extern u64 current_tick_length(void);
298
299extern void second_overflow(void);
300extern void update_ntp_one_tick(void);
301extern int do_adjtimex(struct timex *);
302
303/* Don't use! Compatibility define for existing users. */
304#define tickadj (500/HZ ? : 1)
305
306#endif /* KERNEL */
307
308#endif /* LINUX_TIMEX_H */