1 /*****************************************************************************
3 * Copyright (c) David L. Mills 1993 *
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. *
15 *****************************************************************************/
18 * Modification history timex.h
20 * 29 Dec 97 Russell King
21 * Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
25 * Shifted LATCH define to allow access to alpha machines.
27 * 26 Sep 94 David L. Mills
28 * Added defines for hybrid phase/frequency-lock loop.
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.
34 * 20 Feb 94 David L. Mills
35 * Revised status codes and structures for external clock and PPS
38 * 28 Nov 93 David L. Mills
39 * Adjusted parameters to improve stability and increase poll
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
53 #ifndef _LINUX_TIMEX_H
54 #define _LINUX_TIMEX_H
56 #include <linux/compiler.h>
57 #include <linux/time.h>
59 #include <asm/param.h>
61 #define NTP_API 4 /* NTP API version */
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
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,
74 #define SHIFT_PLL 4 /* PLL frequency factor (shift) */
75 #define SHIFT_FLL 2 /* FLL frequency factor (shift) */
76 #define MAXTC 10 /* maximum time constant (shift) */
79 * The SHIFT_UPDATE define establishes the decimal point of the
80 * time_offset variable which represents the current offset with
81 * respect to standard time.
83 * SHIFT_USEC defines the scaling (shift) of the time_freq and
84 * time_tolerance variables, which represent the current frequency
85 * offset and maximum frequency tolerance.
87 #define SHIFT_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */
88 #define SHIFT_USEC 16 /* frequency offset scale (shift) */
89 #define PPM_SCALE (NSEC_PER_USEC << (TICK_LENGTH_SHIFT - SHIFT_USEC))
90 #define PPM_SCALE_INV_SHIFT 20
91 #define PPM_SCALE_INV ((1ll << (PPM_SCALE_INV_SHIFT + TICK_LENGTH_SHIFT)) / \
94 #define MAXPHASE 512000L /* max phase error (us) */
95 #define MAXFREQ 500000 /* max frequency error (ns/s) */
96 #define MAXFREQ_SCALED ((s64)MAXFREQ << TICK_LENGTH_SHIFT)
97 #define MINSEC 256 /* min interval between updates (s) */
98 #define MAXSEC 2048 /* max interval between updates (s) */
99 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
102 * syscall interface - used (mainly by NTP daemon)
103 * to discipline kernel clock oscillator
106 unsigned int modes; /* mode selector */
107 long offset; /* time offset (usec) */
108 long freq; /* frequency offset (scaled ppm) */
109 long maxerror; /* maximum error (usec) */
110 long esterror; /* estimated error (usec) */
111 int status; /* clock command/status */
112 long constant; /* pll time constant */
113 long precision; /* clock precision (usec) (read only) */
114 long tolerance; /* clock frequency tolerance (ppm)
117 struct timeval time; /* (read only) */
118 long tick; /* (modified) usecs between clock ticks */
120 long ppsfreq; /* pps frequency (scaled ppm) (ro) */
121 long jitter; /* pps jitter (us) (ro) */
122 int shift; /* interval duration (s) (shift) (ro) */
123 long stabil; /* pps stability (scaled ppm) (ro) */
124 long jitcnt; /* jitter limit exceeded (ro) */
125 long calcnt; /* calibration intervals (ro) */
126 long errcnt; /* calibration errors (ro) */
127 long stbcnt; /* stability limit exceeded (ro) */
129 int :32; int :32; int :32; int :32;
130 int :32; int :32; int :32; int :32;
131 int :32; int :32; int :32; int :32;
135 * Mode codes (timex.mode)
137 #define ADJ_OFFSET 0x0001 /* time offset */
138 #define ADJ_FREQUENCY 0x0002 /* frequency offset */
139 #define ADJ_MAXERROR 0x0004 /* maximum time error */
140 #define ADJ_ESTERROR 0x0008 /* estimated time error */
141 #define ADJ_STATUS 0x0010 /* clock status */
142 #define ADJ_TIMECONST 0x0020 /* pll time constant */
143 #define ADJ_MICRO 0x1000 /* select microsecond resolution */
144 #define ADJ_NANO 0x2000 /* select nanosecond resolution */
145 #define ADJ_TICK 0x4000 /* tick value */
146 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
147 #define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
149 /* xntp 3.4 compatibility names */
150 #define MOD_OFFSET ADJ_OFFSET
151 #define MOD_FREQUENCY ADJ_FREQUENCY
152 #define MOD_MAXERROR ADJ_MAXERROR
153 #define MOD_ESTERROR ADJ_ESTERROR
154 #define MOD_STATUS ADJ_STATUS
155 #define MOD_TIMECONST ADJ_TIMECONST
159 * Status codes (timex.status)
161 #define STA_PLL 0x0001 /* enable PLL updates (rw) */
162 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
163 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
164 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
166 #define STA_INS 0x0010 /* insert leap (rw) */
167 #define STA_DEL 0x0020 /* delete leap (rw) */
168 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
169 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
171 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
172 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
173 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
174 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
176 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
177 #define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
178 #define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
179 #define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */
182 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
183 STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)
186 * Clock states (time_state)
188 #define TIME_OK 0 /* clock synchronized, no leap second */
189 #define TIME_INS 1 /* insert leap second */
190 #define TIME_DEL 2 /* delete leap second */
191 #define TIME_OOP 3 /* leap second in progress */
192 #define TIME_WAIT 4 /* leap second has occurred */
193 #define TIME_ERROR 5 /* clock not synchronized */
194 #define TIME_BAD TIME_ERROR /* bw compat */
197 #include <asm/timex.h>
201 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
202 * estimated error = NTP dispersion.
204 extern unsigned long tick_usec; /* USER_HZ period (usec) */
205 extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
206 extern int tickadj; /* amount of adjustment per tick */
209 * phase-lock loop variables
211 extern int time_status; /* clock synchronization status bits */
212 extern long time_maxerror; /* maximum error */
213 extern long time_esterror; /* estimated error */
215 extern long time_adjust; /* The amount of adjtime left */
217 extern void ntp_clear(void);
220 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
223 static inline int ntp_synced(void)
225 return !(time_status & STA_UNSYNC);
228 /* Required to safely shift negative values */
229 #define shift_right(x, s) ({ \
230 __typeof__(x) __x = (x); \
231 __typeof__(s) __s = (s); \
232 __x < 0 ? -(-__x >> __s) : __x >> __s; \
235 #define TICK_LENGTH_SHIFT 32
238 #define NTP_INTERVAL_FREQ (2)
240 #define NTP_INTERVAL_FREQ (HZ)
242 #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
244 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
245 extern u64 current_tick_length(void);
247 extern void second_overflow(void);
248 extern void update_ntp_one_tick(void);
249 extern int do_adjtimex(struct timex *);
251 /* Don't use! Compatibility define for existing users. */
252 #define tickadj (500/HZ ? : 1)
254 int read_current_timer(unsigned long *timer_val);
258 #endif /* LINUX_TIMEX_H */