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/config.h>
57#include <linux/compiler.h>
58#include <linux/time.h>
59
60#include <asm/param.h>
61#include <asm/timex.h>
62
63/*
64 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
65 * for a slightly underdamped convergence characteristic. SHIFT_KH
66 * establishes the damping of the FLL and is chosen by wisdom and black
67 * art.
68 *
69 * MAXTC establishes the maximum time constant of the PLL. With the
70 * SHIFT_KG and SHIFT_KF values given and a time constant range from
71 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
72 * respectively.
73 */
74#define SHIFT_KG 6 /* phase factor (shift) */
75#define SHIFT_KF 16 /* PLL frequency factor (shift) */
76#define SHIFT_KH 2 /* FLL frequency factor (shift) */
77#define MAXTC 6 /* maximum time constant (shift) */
78
79/*
80 * The SHIFT_SCALE define establishes the decimal point of the time_phase
81 * variable which serves as an extension to the low-order bits of the
82 * system clock variable. The SHIFT_UPDATE define establishes the decimal
83 * point of the time_offset variable which represents the current offset
84 * with respect to standard time. The FINENSEC define represents 1 nsec in
85 * scaled units.
86 *
87 * SHIFT_USEC defines the scaling (shift) of the time_freq and
88 * time_tolerance variables, which represent the current frequency
89 * offset and maximum frequency tolerance.
90 *
91 * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable.
92 */
93#define SHIFT_SCALE 22 /* phase scale (shift) */
94#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
95#define SHIFT_USEC 16 /* frequency offset scale (shift) */
96#define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */
97
98#define MAXPHASE 512000L /* max phase error (us) */
99#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
100#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
101#define MINSEC 16L /* min interval between updates (s) */
102#define MAXSEC 1200L /* max interval between updates (s) */
103#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
104
105/*
106 * The following defines are used only if a pulse-per-second (PPS)
107 * signal is available and connected via a modem control lead, such as
108 * produced by the optional ppsclock feature incorporated in the Sun
109 * asynch driver. They establish the design parameters of the frequency-
110 * lock loop used to discipline the CPU clock oscillator to the PPS
111 * signal.
112 *
113 * PPS_AVG is the averaging factor for the frequency loop, as well as
114 * the time and frequency dispersion.
115 *
116 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
117 * calibration intervals, respectively, in seconds as a power of two.
118 *
119 * PPS_VALID is the maximum interval before the PPS signal is considered
120 * invalid and protocol updates used directly instead.
121 *
122 * MAXGLITCH is the maximum interval before a time offset of more than
123 * MAXTIME is believed.
124 */
125#define PPS_AVG 2 /* pps averaging constant (shift) */
126#define PPS_SHIFT 2 /* min interval duration (s) (shift) */
127#define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
128#define PPS_VALID 120 /* pps signal watchdog max (s) */
129#define MAXGLITCH 30 /* pps signal glitch max (s) */
130
131/*
132 * syscall interface - used (mainly by NTP daemon)
133 * to discipline kernel clock oscillator
134 */
135struct timex {
136 unsigned int modes; /* mode selector */
137 long offset; /* time offset (usec) */
138 long freq; /* frequency offset (scaled ppm) */
139 long maxerror; /* maximum error (usec) */
140 long esterror; /* estimated error (usec) */
141 int status; /* clock command/status */
142 long constant; /* pll time constant */
143 long precision; /* clock precision (usec) (read only) */
144 long tolerance; /* clock frequency tolerance (ppm)
145 * (read only)
146 */
147 struct timeval time; /* (read only) */
148 long tick; /* (modified) usecs between clock ticks */
149
150 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
151 long jitter; /* pps jitter (us) (ro) */
152 int shift; /* interval duration (s) (shift) (ro) */
153 long stabil; /* pps stability (scaled ppm) (ro) */
154 long jitcnt; /* jitter limit exceeded (ro) */
155 long calcnt; /* calibration intervals (ro) */
156 long errcnt; /* calibration errors (ro) */
157 long stbcnt; /* stability limit exceeded (ro) */
158
159 int :32; int :32; int :32; int :32;
160 int :32; int :32; int :32; int :32;
161 int :32; int :32; int :32; int :32;
162};
163
164/*
165 * Mode codes (timex.mode)
166 */
167#define ADJ_OFFSET 0x0001 /* time offset */
168#define ADJ_FREQUENCY 0x0002 /* frequency offset */
169#define ADJ_MAXERROR 0x0004 /* maximum time error */
170#define ADJ_ESTERROR 0x0008 /* estimated time error */
171#define ADJ_STATUS 0x0010 /* clock status */
172#define ADJ_TIMECONST 0x0020 /* pll time constant */
173#define ADJ_TICK 0x4000 /* tick value */
174#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
175
176/* xntp 3.4 compatibility names */
177#define MOD_OFFSET ADJ_OFFSET
178#define MOD_FREQUENCY ADJ_FREQUENCY
179#define MOD_MAXERROR ADJ_MAXERROR
180#define MOD_ESTERROR ADJ_ESTERROR
181#define MOD_STATUS ADJ_STATUS
182#define MOD_TIMECONST ADJ_TIMECONST
183#define MOD_CLKB ADJ_TICK
184#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
185
186
187/*
188 * Status codes (timex.status)
189 */
190#define STA_PLL 0x0001 /* enable PLL updates (rw) */
191#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
192#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
193#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
194
195#define STA_INS 0x0010 /* insert leap (rw) */
196#define STA_DEL 0x0020 /* delete leap (rw) */
197#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
198#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
199
200#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
201#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
202#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
203#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
204
205#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
206
207#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
208 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
209
210/*
211 * Clock states (time_state)
212 */
213#define TIME_OK 0 /* clock synchronized, no leap second */
214#define TIME_INS 1 /* insert leap second */
215#define TIME_DEL 2 /* delete leap second */
216#define TIME_OOP 3 /* leap second in progress */
217#define TIME_WAIT 4 /* leap second has occurred */
218#define TIME_ERROR 5 /* clock not synchronized */
219#define TIME_BAD TIME_ERROR /* bw compat */
220
221#ifdef __KERNEL__
222/*
223 * kernel variables
224 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
225 * estimated error = NTP dispersion.
226 */
227extern unsigned long tick_usec; /* USER_HZ period (usec) */
228extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
229extern int tickadj; /* amount of adjustment per tick */
230
231/*
232 * phase-lock loop variables
233 */
234extern int time_state; /* clock status */
235extern int time_status; /* clock synchronization status bits */
236extern long time_offset; /* time adjustment (us) */
237extern long time_constant; /* pll time constant */
238extern long time_tolerance; /* frequency tolerance (ppm) */
239extern long time_precision; /* clock precision (us) */
240extern long time_maxerror; /* maximum error */
241extern long time_esterror; /* estimated error */
242
243extern long time_freq; /* frequency offset (scaled ppm) */
244extern long time_reftime; /* time at last adjustment (s) */
245
246extern long time_adjust; /* The amount of adjtime left */
247extern long time_next_adjust; /* Value for time_adjust at next tick */
248
249/* interface variables pps->timer interrupt */
250extern long pps_offset; /* pps time offset (us) */
251extern long pps_jitter; /* time dispersion (jitter) (us) */
252extern long pps_freq; /* frequency offset (scaled ppm) */
253extern long pps_stabil; /* frequency dispersion (scaled ppm) */
254extern long pps_valid; /* pps signal watchdog counter */
255
256/* interface variables pps->adjtimex */
257extern int pps_shift; /* interval duration (s) (shift) */
258extern long pps_jitcnt; /* jitter limit exceeded */
259extern long pps_calcnt; /* calibration intervals */
260extern long pps_errcnt; /* calibration errors */
261extern long pps_stbcnt; /* stability limit exceeded */
262
263#ifdef CONFIG_TIME_INTERPOLATION
264
265#define TIME_SOURCE_CPU 0
266#define TIME_SOURCE_MMIO64 1
267#define TIME_SOURCE_MMIO32 2
268#define TIME_SOURCE_FUNCTION 3
269
270/* For proper operations time_interpolator clocks must run slightly slower
271 * than the standard clock since the interpolator may only correct by having
272 * time jump forward during a tick. A slower clock is usually a side effect
273 * of the integer divide of the nanoseconds in a second by the frequency.
274 * The accuracy of the division can be increased by specifying a shift.
275 * However, this may cause the clock not to be slow enough.
276 * The interpolator will self-tune the clock by slowing down if no
277 * resets occur or speeding up if the time jumps per analysis cycle
278 * become too high.
279 *
280 * Setting jitter compensates for a fluctuating timesource by comparing
281 * to the last value read from the timesource to insure that an earlier value
282 * is not returned by a later call. The price to pay
283 * for the compensation is that the timer routines are not as scalable anymore.
284 */
285
286struct time_interpolator {
287 u16 source; /* time source flags */
288 u8 shift; /* increases accuracy of multiply by shifting. */
289 /* Note that bits may be lost if shift is set too high */
290 u8 jitter; /* if set compensate for fluctuations */
291 u32 nsec_per_cyc; /* set by register_time_interpolator() */
292 void *addr; /* address of counter or function */
293 u64 mask; /* mask the valid bits of the counter */
294 unsigned long offset; /* nsec offset at last update of interpolator */
295 u64 last_counter; /* counter value in units of the counter at last update */
296 u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */
297 u64 frequency; /* frequency in counts/second */
298 long drift; /* drift in parts-per-million (or -1) */
299 unsigned long skips; /* skips forward */
300 unsigned long ns_skipped; /* nanoseconds skipped */
301 struct time_interpolator *next;
302};
303
304extern void register_time_interpolator(struct time_interpolator *);
305extern void unregister_time_interpolator(struct time_interpolator *);
306extern void time_interpolator_reset(void);
307extern unsigned long time_interpolator_get_offset(void);
308
309#else /* !CONFIG_TIME_INTERPOLATION */
310
311static inline void
312time_interpolator_reset(void)
313{
314}
315
316#endif /* !CONFIG_TIME_INTERPOLATION */
317
318#endif /* KERNEL */
319
320#endif /* LINUX_TIMEX_H */