File: /usr/src/linux/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 >= 12 && HZ < 24
64 # define SHIFT_HZ 4
65 #elif HZ >= 24 && HZ < 48
66 # define SHIFT_HZ 5
67 #elif HZ >= 48 && HZ < 96
68 # define SHIFT_HZ 6
69 #elif HZ >= 96 && HZ < 192
70 # define SHIFT_HZ 7
71 #elif HZ >= 192 && HZ < 384
72 # define SHIFT_HZ 8
73 #elif HZ >= 384 && HZ < 768
74 # define SHIFT_HZ 9
75 #elif HZ >= 768 && HZ < 1536
76 # define SHIFT_HZ 10
77 #else
78 # error You lose.
79 #endif
80
81 /*
82 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
83 * for a slightly underdamped convergence characteristic. SHIFT_KH
84 * establishes the damping of the FLL and is chosen by wisdom and black
85 * art.
86 *
87 * MAXTC establishes the maximum time constant of the PLL. With the
88 * SHIFT_KG and SHIFT_KF values given and a time constant range from
89 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
90 * respectively.
91 */
92 #define SHIFT_KG 6 /* phase factor (shift) */
93 #define SHIFT_KF 16 /* PLL frequency factor (shift) */
94 #define SHIFT_KH 2 /* FLL frequency factor (shift) */
95 #define MAXTC 6 /* maximum time constant (shift) */
96
97 /*
98 * The SHIFT_SCALE define establishes the decimal point of the time_phase
99 * variable which serves as an extension to the low-order bits of the
100 * system clock variable. The SHIFT_UPDATE define establishes the decimal
101 * point of the time_offset variable which represents the current offset
102 * with respect to standard time. The FINEUSEC define represents 1 usec in
103 * scaled units.
104 *
105 * SHIFT_USEC defines the scaling (shift) of the time_freq and
106 * time_tolerance variables, which represent the current frequency
107 * offset and maximum frequency tolerance.
108 *
109 * FINEUSEC is 1 us in SHIFT_UPDATE units of the time_phase variable.
110 */
111 #define SHIFT_SCALE 22 /* phase scale (shift) */
112 #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
113 #define SHIFT_USEC 16 /* frequency offset scale (shift) */
114 #define FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */
115
116 #define MAXPHASE 512000L /* max phase error (us) */
117 #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
118 #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
119 #define MINSEC 16L /* min interval between updates (s) */
120 #define MAXSEC 1200L /* max interval between updates (s) */
121 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
122
123 /*
124 * The following defines are used only if a pulse-per-second (PPS)
125 * signal is available and connected via a modem control lead, such as
126 * produced by the optional ppsclock feature incorporated in the Sun
127 * asynch driver. They establish the design parameters of the frequency-
128 * lock loop used to discipline the CPU clock oscillator to the PPS
129 * signal.
130 *
131 * PPS_AVG is the averaging factor for the frequency loop, as well as
132 * the time and frequency dispersion.
133 *
134 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
135 * calibration intervals, respectively, in seconds as a power of two.
136 *
137 * PPS_VALID is the maximum interval before the PPS signal is considered
138 * invalid and protocol updates used directly instead.
139 *
140 * MAXGLITCH is the maximum interval before a time offset of more than
141 * MAXTIME is believed.
142 */
143 #define PPS_AVG 2 /* pps averaging constant (shift) */
144 #define PPS_SHIFT 2 /* min interval duration (s) (shift) */
145 #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
146 #define PPS_VALID 120 /* pps signal watchdog max (s) */
147 #define MAXGLITCH 30 /* pps signal glitch max (s) */
148
149 /*
150 * Pick up the architecture specific timex specifications
151 */
152 #include <asm/timex.h>
153
154 /* LATCH is used in the interval timer and ftape setup. */
155 #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
156
157 /*
158 * syscall interface - used (mainly by NTP daemon)
159 * to discipline kernel clock oscillator
160 */
161 struct timex {
162 unsigned int modes; /* mode selector */
163 long offset; /* time offset (usec) */
164 long freq; /* frequency offset (scaled ppm) */
165 long maxerror; /* maximum error (usec) */
166 long esterror; /* estimated error (usec) */
167 int status; /* clock command/status */
168 long constant; /* pll time constant */
169 long precision; /* clock precision (usec) (read only) */
170 long tolerance; /* clock frequency tolerance (ppm)
171 * (read only)
172 */
173 struct timeval time; /* (read only) */
174 long tick; /* (modified) usecs between clock ticks */
175
176 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
177 long jitter; /* pps jitter (us) (ro) */
178 int shift; /* interval duration (s) (shift) (ro) */
179 long stabil; /* pps stability (scaled ppm) (ro) */
180 long jitcnt; /* jitter limit exceeded (ro) */
181 long calcnt; /* calibration intervals (ro) */
182 long errcnt; /* calibration errors (ro) */
183 long stbcnt; /* stability limit exceeded (ro) */
184
185 int :32; int :32; int :32; int :32;
186 int :32; int :32; int :32; int :32;
187 int :32; int :32; int :32; int :32;
188 };
189
190 /*
191 * Mode codes (timex.mode)
192 */
193 #define ADJ_OFFSET 0x0001 /* time offset */
194 #define ADJ_FREQUENCY 0x0002 /* frequency offset */
195 #define ADJ_MAXERROR 0x0004 /* maximum time error */
196 #define ADJ_ESTERROR 0x0008 /* estimated time error */
197 #define ADJ_STATUS 0x0010 /* clock status */
198 #define ADJ_TIMECONST 0x0020 /* pll time constant */
199 #define ADJ_TICK 0x4000 /* tick value */
200 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
201
202 /* xntp 3.4 compatibility names */
203 #define MOD_OFFSET ADJ_OFFSET
204 #define MOD_FREQUENCY ADJ_FREQUENCY
205 #define MOD_MAXERROR ADJ_MAXERROR
206 #define MOD_ESTERROR ADJ_ESTERROR
207 #define MOD_STATUS ADJ_STATUS
208 #define MOD_TIMECONST ADJ_TIMECONST
209 #define MOD_CLKB ADJ_TICK
210 #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
211
212
213 /*
214 * Status codes (timex.status)
215 */
216 #define STA_PLL 0x0001 /* enable PLL updates (rw) */
217 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
218 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
219 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
220
221 #define STA_INS 0x0010 /* insert leap (rw) */
222 #define STA_DEL 0x0020 /* delete leap (rw) */
223 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
224 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
225
226 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
227 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
228 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
229 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
230
231 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
232
233 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
234 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
235
236 /*
237 * Clock states (time_state)
238 */
239 #define TIME_OK 0 /* clock synchronized, no leap second */
240 #define TIME_INS 1 /* insert leap second */
241 #define TIME_DEL 2 /* delete leap second */
242 #define TIME_OOP 3 /* leap second in progress */
243 #define TIME_WAIT 4 /* leap second has occurred */
244 #define TIME_ERROR 5 /* clock not synchronized */
245 #define TIME_BAD TIME_ERROR /* bw compat */
246
247 #ifdef __KERNEL__
248 /*
249 * kernel variables
250 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
251 * estimated error = NTP dispersion.
252 */
253 extern long tick; /* timer interrupt period */
254 extern int tickadj; /* amount of adjustment per tick */
255
256 /*
257 * phase-lock loop variables
258 */
259 extern int time_state; /* clock status */
260 extern int time_status; /* clock synchronization status bits */
261 extern long time_offset; /* time adjustment (us) */
262 extern long time_constant; /* pll time constant */
263 extern long time_tolerance; /* frequency tolerance (ppm) */
264 extern long time_precision; /* clock precision (us) */
265 extern long time_maxerror; /* maximum error */
266 extern long time_esterror; /* estimated error */
267
268 extern long time_phase; /* phase offset (scaled us) */
269 extern long time_freq; /* frequency offset (scaled ppm) */
270 extern long time_adj; /* tick adjust (scaled 1 / HZ) */
271 extern long time_reftime; /* time at last adjustment (s) */
272
273 extern long time_adjust; /* The amount of adjtime left */
274
275 /* interface variables pps->timer interrupt */
276 extern long pps_offset; /* pps time offset (us) */
277 extern long pps_jitter; /* time dispersion (jitter) (us) */
278 extern long pps_freq; /* frequency offset (scaled ppm) */
279 extern long pps_stabil; /* frequency dispersion (scaled ppm) */
280 extern long pps_valid; /* pps signal watchdog counter */
281
282 /* interface variables pps->adjtimex */
283 extern int pps_shift; /* interval duration (s) (shift) */
284 extern long pps_jitcnt; /* jitter limit exceeded */
285 extern long pps_calcnt; /* calibration intervals */
286 extern long pps_errcnt; /* calibration errors */
287 extern long pps_stbcnt; /* stability limit exceeded */
288
289 #endif /* KERNEL */
290
291 #endif /* LINUX_TIMEX_H */
292