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 */
100 struct 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 #define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
141
142 /* xntp 3.4 compatibility names */
143 #define MOD_OFFSET ADJ_OFFSET
144 #define MOD_FREQUENCY ADJ_FREQUENCY
145 #define MOD_MAXERROR ADJ_MAXERROR
146 #define MOD_ESTERROR ADJ_ESTERROR
147 #define MOD_STATUS ADJ_STATUS
148 #define MOD_TIMECONST ADJ_TIMECONST
149 #define MOD_CLKB ADJ_TICK
150 #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
151
152
153 /*
154 * Status codes (timex.status)
155 */
156 #define STA_PLL 0x0001 /* enable PLL updates (rw) */
157 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
158 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
159 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
160
161 #define STA_INS 0x0010 /* insert leap (rw) */
162 #define STA_DEL 0x0020 /* delete leap (rw) */
163 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
164 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
165
166 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
167 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
168 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
169 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
170
171 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
172
173 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
174 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
175
176 /*
177 * Clock states (time_state)
178 */
179 #define TIME_OK 0 /* clock synchronized, no leap second */
180 #define TIME_INS 1 /* insert leap second */
181 #define TIME_DEL 2 /* delete leap second */
182 #define TIME_OOP 3 /* leap second in progress */
183 #define TIME_WAIT 4 /* leap second has occurred */
184 #define TIME_ERROR 5 /* clock not synchronized */
185 #define TIME_BAD TIME_ERROR /* bw compat */
186
187 #ifdef __KERNEL__
188 #include <asm/timex.h>
189
190 /*
191 * kernel variables
192 * Note: maximum error = NTP synch distance = dispersion + delay / 2;
193 * estimated error = NTP dispersion.
194 */
195 extern unsigned long tick_usec; /* USER_HZ period (usec) */
196 extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
197 extern int tickadj; /* amount of adjustment per tick */
198
199 /*
200 * phase-lock loop variables
201 */
202 extern int time_status; /* clock synchronization status bits */
203 extern long time_maxerror; /* maximum error */
204 extern long time_esterror; /* estimated error */
205
206 extern long time_freq; /* frequency offset (scaled ppm) */
207
208 extern long time_adjust; /* The amount of adjtime left */
209
210 extern void ntp_clear(void);
211
212 /**
213 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
214 *
215 */
216 static inline int ntp_synced(void)
217 {
218 return !(time_status & STA_UNSYNC);
219 }
220
221 /* Required to safely shift negative values */
222 #define shift_right(x, s) ({ \
223 __typeof__(x) __x = (x); \
224 __typeof__(s) __s = (s); \
225 __x < 0 ? -(-__x >> __s) : __x >> __s; \
226 })
227
228 #define TICK_LENGTH_SHIFT 32
229
230 #ifdef CONFIG_NO_HZ
231 #define NTP_INTERVAL_FREQ (2)
232 #else
233 #define NTP_INTERVAL_FREQ (HZ)
234 #endif
235 #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
236
237 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
238 extern u64 current_tick_length(void);
239
240 extern void second_overflow(void);
241 extern void update_ntp_one_tick(void);
242 extern int do_adjtimex(struct timex *);
243
244 /* Don't use! Compatibility define for existing users. */
245 #define tickadj (500/HZ ? : 1)
246
247 int read_current_timer(unsigned long *timer_val);
248
249 #endif /* KERNEL */
250
251 #endif /* LINUX_TIMEX_H */
252
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