File: /usr/include/linux/timex.h
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 */
51 #ifndef _LINUX_TIMEX_H
52 #define _LINUX_TIMEX_H
53
54 #include <asm/param.h>
55
56 /*
57 * The following defines establish the engineering parameters of the PLL
58 * model. The HZ variable establishes the timer interrupt frequency, 100 Hz
59 * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the
60 * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the
61 * nearest power of two in order to avoid hardware multiply operations.
62 */
63 #if HZ >= 24 && HZ < 48
64 # define SHIFT_HZ 5
65 #elif HZ >= 48 && HZ < 96
66 # define SHIFT_HZ 6
67 #elif HZ >= 96 && HZ < 192
68 # define SHIFT_HZ 7
69 #elif HZ >= 192 && HZ < 384
70 # define SHIFT_HZ 8
71 #elif HZ >= 384 && HZ < 768
72 # define SHIFT_HZ 9
73 #elif HZ >= 768 && HZ < 1536
74 # define SHIFT_HZ 10
75 #else
76 # error You lose.
77 #endif
78
79 /*
80 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
81 * for a slightly underdamped convergence characteristic. SHIFT_KH
82 * establishes the damping of the FLL and is chosen by wisdom and black
83 * art.
84 *
85 * MAXTC establishes the maximum time constant of the PLL. With the
86 * SHIFT_KG and SHIFT_KF values given and a time constant range from
87 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
88 * respectively.
89 */
90 #define SHIFT_KG 6 /* phase factor (shift) */
91 #define SHIFT_KF 16 /* PLL frequency factor (shift) */
92 #define SHIFT_KH 2 /* FLL frequency factor (shift) */
93 #define MAXTC 6 /* maximum time constant (shift) */
94
95 /*
96 * The SHIFT_SCALE define establishes the decimal point of the time_phase
97 * variable which serves as an extension to the low-order bits of the
98 * system clock variable. The SHIFT_UPDATE define establishes the decimal
99 * point of the time_offset variable which represents the current offset
100 * with respect to standard time. The FINEUSEC define represents 1 usec in
101 * scaled units.
102 *
103 * SHIFT_USEC defines the scaling (shift) of the time_freq and
104 * time_tolerance variables, which represent the current frequency
105 * offset and maximum frequency tolerance.
106 *
107 * FINEUSEC is 1 us in SHIFT_UPDATE units of the time_phase variable.
108 */
109 #define SHIFT_SCALE 22 /* phase scale (shift) */
110 #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
111 #define SHIFT_USEC 16 /* frequency offset scale (shift) */
112 #define FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */
113
114 #define MAXPHASE 512000L /* max phase error (us) */
115 #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
116 #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
117 #define MINSEC 16L /* min interval between updates (s) */
118 #define MAXSEC 1200L /* max interval between updates (s) */
119 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
120
121 /*
122 * The following defines are used only if a pulse-per-second (PPS)
123 * signal is available and connected via a modem control lead, such as
124 * produced by the optional ppsclock feature incorporated in the Sun
125 * asynch driver. They establish the design parameters of the frequency-
126 * lock loop used to discipline the CPU clock oscillator to the PPS
127 * signal.
128 *
129 * PPS_AVG is the averaging factor for the frequency loop, as well as
130 * the time and frequency dispersion.
131 *
132 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
133 * calibration intervals, respectively, in seconds as a power of two.
134 *
135 * PPS_VALID is the maximum interval before the PPS signal is considered
136 * invalid and protocol updates used directly instead.
137 *
138 * MAXGLITCH is the maximum interval before a time offset of more than
139 * MAXTIME is believed.
140 */
141 #define PPS_AVG 2 /* pps averaging constant (shift) */
142 #define PPS_SHIFT 2 /* min interval duration (s) (shift) */
143 #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
144 #define PPS_VALID 120 /* pps signal watchdog max (s) */
145 #define MAXGLITCH 30 /* pps signal glitch max (s) */
146
147 /*
148 * Pick up the architecture specific timex specifications
149 */
150 #include <asm/timex.h>
151
152 /* LATCH is used in the interval timer and ftape setup. */
153 #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
154
155 /*
156 * syscall interface - used (mainly by NTP daemon)
157 * to discipline kernel clock oscillator
158 */
159 struct timex {
160 unsigned int modes; /* mode selector */
161 long offset; /* time offset (usec) */
162 long freq; /* frequency offset (scaled ppm) */
163 long maxerror; /* maximum error (usec) */
164 long esterror; /* estimated error (usec) */
165 int status; /* clock command/status */
166 long constant; /* pll time constant */
167 long precision; /* clock precision (usec) (read only) */
168 long tolerance; /* clock frequency tolerance (ppm)
169 * (read only)
170 */
171 struct timeval time; /* (read only) */
172 long tick; /* (modified) usecs between clock ticks */
173
174 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
175 long jitter; /* pps jitter (us) (ro) */
176 int shift; /* interval duration (s) (shift) (ro) */
177 long stabil; /* pps stability (scaled ppm) (ro) */
178 long jitcnt; /* jitter limit exceeded (ro) */
179 long calcnt; /* calibration intervals (ro) */
180 long errcnt; /* calibration errors (ro) */
181 long stbcnt; /* stability limit exceeded (ro) */
182
183 int :32; int :32; int :32; int :32;
184 int :32; int :32; int :32; int :32;
185 int :32; int :32; int :32; int :32;
186 };
187
188 /*
189 * Mode codes (timex.mode)
190 */
191 #define ADJ_OFFSET 0x0001 /* time offset */
192 #define ADJ_FREQUENCY 0x0002 /* frequency offset */
193 #define ADJ_MAXERROR 0x0004 /* maximum time error */
194 #define ADJ_ESTERROR 0x0008 /* estimated time error */
195 #define ADJ_STATUS 0x0010 /* clock status */
196 #define ADJ_TIMECONST 0x0020 /* pll time constant */
197 #define ADJ_TICK 0x4000 /* tick value */
198 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
199
200 /* xntp 3.4 compatibility names */
201 #define MOD_OFFSET ADJ_OFFSET
202 #define MOD_FREQUENCY ADJ_FREQUENCY
203 #define MOD_MAXERROR ADJ_MAXERROR
204 #define MOD_ESTERROR ADJ_ESTERROR
205 #define MOD_STATUS ADJ_STATUS
206 #define MOD_TIMECONST ADJ_TIMECONST
207 #define MOD_CLKB ADJ_TICK
208 #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
209
210
211 /*
212 * Status codes (timex.status)
213 */
214 #define STA_PLL 0x0001 /* enable PLL updates (rw) */
215 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
216 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
217 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
218
219 #define STA_INS 0x0010 /* insert leap (rw) */
220 #define STA_DEL 0x0020 /* delete leap (rw) */
221 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
222 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
223
224 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
225 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
226 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
227 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
228
229 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
230
231 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
232 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
233
234 /*
235 * Clock states (time_state)
236 */
237 #define TIME_OK 0 /* clock synchronized, no leap second */
238 #define TIME_INS 1 /* insert leap second */
239 #define TIME_DEL 2 /* delete leap second */
240 #define TIME_OOP 3 /* leap second in progress */
241 #define TIME_WAIT 4 /* leap second has occurred */
242 #define TIME_ERROR 5 /* clock not synchronized */
243 #define TIME_BAD TIME_ERROR /* bw compat */
244
245 #ifdef __KERNEL__
246 /*
247 * kernel variables
248 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
249 * estimated error = NTP dispersion.
250 */
251 extern long tick; /* timer interrupt period */
252 extern int tickadj; /* amount of adjustment per tick */
253
254 /*
255 * phase-lock loop variables
256 */
257 extern int time_state; /* clock status */
258 extern int time_status; /* clock synchronization status bits */
259 extern long time_offset; /* time adjustment (us) */
260 extern long time_constant; /* pll time constant */
261 extern long time_tolerance; /* frequency tolerance (ppm) */
262 extern long time_precision; /* clock precision (us) */
263 extern long time_maxerror; /* maximum error */
264 extern long time_esterror; /* estimated error */
265
266 extern long time_phase; /* phase offset (scaled us) */
267 extern long time_freq; /* frequency offset (scaled ppm) */
268 extern long time_adj; /* tick adjust (scaled 1 / HZ) */
269 extern long time_reftime; /* time at last adjustment (s) */
270
271 extern long time_adjust; /* The amount of adjtime left */
272
273 /* interface variables pps->timer interrupt */
274 extern long pps_offset; /* pps time offset (us) */
275 extern long pps_jitter; /* time dispersion (jitter) (us) */
276 extern long pps_freq; /* frequency offset (scaled ppm) */
277 extern long pps_stabil; /* frequency dispersion (scaled ppm) */
278 extern long pps_valid; /* pps signal watchdog counter */
279
280 /* interface variables pps->adjtimex */
281 extern int pps_shift; /* interval duration (s) (shift) */
282 extern long pps_jitcnt; /* jitter limit exceeded */
283 extern long pps_calcnt; /* calibration intervals */
284 extern long pps_errcnt; /* calibration errors */
285 extern long pps_stbcnt; /* stability limit exceeded */
286
287 #endif /* KERNEL */
288
289 #endif /* LINUX_TIMEX_H */
290