Annotation of embedaddon/ntp/kernel/sys/timex.h, revision 1.1.1.1
1.1 misho 1: /******************************************************************************
2: * *
3: * Copyright (c) David L. Mills 1993, 1994 *
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: * 26 Sep 94 David L. Mills
21: * Added defines for hybrid phase/frequency-lock loop.
22: *
23: * 19 Mar 94 David L. Mills
24: * Moved defines from kernel routines to header file and added new
25: * defines for PPS phase-lock loop.
26: *
27: * 20 Feb 94 David L. Mills
28: * Revised status codes and structures for external clock and PPS
29: * signal discipline.
30: *
31: * 28 Nov 93 David L. Mills
32: * Adjusted parameters to improve stability and increase poll
33: * interval.
34: *
35: * 17 Sep 93 David L. Mills
36: * Created file
37: */
38: /*
39: * This header file defines the Network Time Protocol (NTP) interfaces
40: * for user and daemon application programs. These are implemented using
41: * private syscalls and data structures and require specific kernel
42: * support.
43: *
44: * NAME
45: * ntp_gettime - NTP user application interface
46: *
47: * SYNOPSIS
48: * #include <sys/timex.h>
49: *
50: * int syscall(SYS_ntp_gettime, tptr)
51: *
52: * int SYS_ntp_gettime defined in syscall.h header file
53: * struct ntptimeval *tptr pointer to ntptimeval structure
54: *
55: * NAME
56: * ntp_adjtime - NTP daemon application interface
57: *
58: * SYNOPSIS
59: * #include <sys/timex.h>
60: *
61: * int syscall(SYS_ntp_adjtime, mode, tptr)
62: *
63: * int SYS_ntp_adjtime defined in syscall.h header file
64: * struct timex *tptr pointer to timex structure
65: *
66: */
67: #ifndef _SYS_TIMEX_H_
68: #define _SYS_TIMEX_H_ 1
69:
70: #ifndef MSDOS /* Microsoft specific */
71: #include <sys/syscall.h>
72: #endif /* MSDOS */
73:
74: /*
75: * The following defines establish the engineering parameters of the
76: * phase-lock loop (PLL) model used in the kernel implementation. These
77: * parameters have been carefully chosen by analysis for good stability
78: * and wide dynamic range.
79: *
80: * The hz variable is defined in the kernel build environment. It
81: * establishes the timer interrupt frequency, 100 Hz for the SunOS
82: * kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the OSF/1
83: * kernel. SHIFT_HZ expresses the same value as the nearest power of two
84: * in order to avoid hardware multiply operations.
85: *
86: * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
87: * for a slightly underdamped convergence characteristic. SHIFT_KH
88: * establishes the damping of the FLL and is chosen by wisdom and black
89: * art.
90: *
91: * MAXTC establishes the maximum time constant of the PLL. With the
92: * SHIFT_KG and SHIFT_KF values given and a time constant range from
93: * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
94: * respectively.
95: */
96: #define SHIFT_HZ 7 /* log2(hz) */
97: #define SHIFT_KG 6 /* phase factor (shift) */
98: #define SHIFT_KF 16 /* PLL frequency factor (shift) */
99: #define SHIFT_KH 2 /* FLL frequency factor (shift) */
100: #define MAXTC 6 /* maximum time constant (shift) */
101:
102: /*
103: * The following defines establish the scaling of the various variables
104: * used by the PLL. They are chosen to allow the greatest precision
105: * possible without overflow of a 32-bit word.
106: *
107: * SHIFT_SCALE defines the scaling (shift) of the time_phase variable,
108: * which serves as a an extension to the low-order bits of the system
109: * clock variable time.tv_usec.
110: *
111: * SHIFT_UPDATE defines the scaling (shift) of the time_offset variable,
112: * which represents the current time offset with respect to standard
113: * time.
114: *
115: * SHIFT_USEC defines the scaling (shift) of the time_freq and
116: * time_tolerance variables, which represent the current frequency
117: * offset and maximum frequency tolerance.
118: *
119: * FINEUSEC is 1 us in SHIFT_UPDATE units of the time_phase variable.
120: */
121: #define SHIFT_SCALE 22 /* phase scale (shift) */
122: #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
123: #define SHIFT_USEC 16 /* frequency offset scale (shift) */
124: #define FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */
125:
126: /*
127: * The following defines establish the performance envelope of the PLL.
128: * They insure it operates within predefined limits, in order to satisfy
129: * correctness assertions. An excursion which exceeds these bounds is
130: * clamped to the bound and operation proceeds accordingly. In practice,
131: * this can occur only if something has failed or is operating out of
132: * tolerance, but otherwise the PLL continues to operate in a stable
133: * mode.
134: *
135: * MAXPHASE must be set greater than or equal to CLOCK.MAX (128 ms), as
136: * defined in the NTP specification. CLOCK.MAX establishes the maximum
137: * time offset allowed before the system time is reset, rather than
138: * incrementally adjusted. Here, the maximum offset is clamped to
139: * MAXPHASE only in order to prevent overflow errors due to defective
140: * protocol implementations.
141: *
142: * MAXFREQ is the maximum frequency tolerance of the CPU clock
143: * oscillator plus the maximum slew rate allowed by the protocol. It
144: * should be set to at least the frequency tolerance of the oscillator
145: * plus 100 ppm for vernier frequency adjustments. If the kernel
146: * PPS discipline code is configured (PPS_SYNC), the oscillator time and
147: * frequency are disciplined to an external source, presumably with
148: * negligible time and frequency error relative to UTC, and MAXFREQ can
149: * be reduced.
150: *
151: * MAXTIME is the maximum jitter tolerance of the PPS signal if the
152: * kernel PPS discipline code is configured (PPS_SYNC).
153: *
154: * MINSEC and MAXSEC define the lower and upper bounds on the interval
155: * between protocol updates.
156: */
157: #define MAXPHASE 512000L /* max phase error (us) */
158: #ifdef PPS_SYNC
159: #define MAXFREQ (512L << SHIFT_USEC) /* max freq error (100 ppm) */
160: #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
161: #else
162: #define MAXFREQ (512L << SHIFT_USEC) /* max freq error (200 ppm) */
163: #endif /* PPS_SYNC */
164: #define MINSEC 16L /* min interval between updates (s) */
165: #define MAXSEC 1200L /* max interval between updates (s) */
166:
167: #ifdef PPS_SYNC
168: /*
169: * The following defines are used only if a pulse-per-second (PPS)
170: * signal is available and connected via a modem control lead, such as
171: * produced by the optional ppsclock feature incorporated in the Sun
172: * asynch driver. They establish the design parameters of the frequency-
173: * lock loop used to discipline the CPU clock oscillator to the PPS
174: * signal.
175: *
176: * PPS_AVG is the averaging factor for the frequency loop, as well as
177: * the time and frequency dispersion.
178: *
179: * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
180: * calibration intervals, respectively, in seconds as a power of two.
181: *
182: * PPS_VALID is the maximum interval before the PPS signal is considered
183: * invalid and protocol updates used directly instead.
184: *
185: * MAXGLITCH is the maximum interval before a time offset of more than
186: * MAXTIME is believed.
187: */
188: #define PPS_AVG 2 /* pps averaging constant (shift) */
189: #define PPS_SHIFT 2 /* min interval duration (s) (shift) */
190: #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
191: #define PPS_VALID 120 /* pps signal watchdog max (s) */
192: #define MAXGLITCH 30 /* pps signal glitch max (s) */
193: #endif /* PPS_SYNC */
194:
195: /*
196: * The following defines and structures define the user interface for
197: * the ntp_gettime() and ntp_adjtime() system calls.
198: *
199: * Control mode codes (timex.modes)
200: */
201: #define MOD_OFFSET 0x0001 /* set time offset */
202: #define MOD_FREQUENCY 0x0002 /* set frequency offset */
203: #define MOD_MAXERROR 0x0004 /* set maximum time error */
204: #define MOD_ESTERROR 0x0008 /* set estimated time error */
205: #define MOD_STATUS 0x0010 /* set clock status bits */
206: #define MOD_TIMECONST 0x0020 /* set pll time constant */
207: #define MOD_CANSCALE 0x0040 /* kernel can scale offset field */
208: #define MOD_DOSCALE 0x0080 /* userland wants to scale offset field */
209:
210: /*
211: * Status codes (timex.status)
212: */
213: #define STA_PLL 0x0001 /* enable PLL updates (rw) */
214: #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
215: #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
216: #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
217:
218: #define STA_INS 0x0010 /* insert leap (rw) */
219: #define STA_DEL 0x0020 /* delete leap (rw) */
220: #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
221: #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
222:
223: #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
224: #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
225: #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
226: #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
227:
228: #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
229:
230: #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
231: STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
232:
233: /*
234: * Clock states (time_state)
235: */
236: #define TIME_OK 0 /* no leap second warning */
237: #define TIME_INS 1 /* insert leap second warning */
238: #define TIME_DEL 2 /* delete leap second warning */
239: #define TIME_OOP 3 /* leap second in progress */
240: #define TIME_WAIT 4 /* leap second has occurred */
241: #define TIME_ERROR 5 /* clock not synchronized */
242:
243: /*
244: * NTP user interface (ntp_gettime()) - used to read kernel clock values
245: *
246: * Note: maximum error = NTP synch distance = dispersion + delay / 2;
247: * estimated error = NTP dispersion.
248: */
249: struct ntptimeval {
250: struct timeval time; /* current time (ro) */
251: long maxerror; /* maximum error (us) (ro) */
252: long esterror; /* estimated error (us) (ro) */
253: };
254:
255: /*
256: * NTP daemon interface - (ntp_adjtime()) used to discipline CPU clock
257: * oscillator
258: */
259: struct timex {
260: unsigned int modes; /* clock mode bits (wo) */
261: long offset; /* time offset (us) (rw) */
262: long freq; /* frequency offset (scaled ppm) (rw) */
263: long maxerror; /* maximum error (us) (rw) */
264: long esterror; /* estimated error (us) (rw) */
265: int status; /* clock status bits (rw) */
266: long constant; /* pll time constant (rw) */
267: long precision; /* clock precision (us) (ro) */
268: long tolerance; /* clock frequency tolerance (scaled
269: * ppm) (ro) */
270: /*
271: * The following read-only structure members are implemented
272: * only if the PPS signal discipline is configured in the
273: * kernel.
274: */
275: long ppsfreq; /* pps frequency (scaled ppm) (ro) */
276: long jitter; /* pps jitter (us) (ro) */
277: int shift; /* interval duration (s) (shift) (ro) */
278: long stabil; /* pps stability (scaled ppm) (ro) */
279: long jitcnt; /* jitter limit exceeded (ro) */
280: long calcnt; /* calibration intervals (ro) */
281: long errcnt; /* calibration errors (ro) */
282: long stbcnt; /* stability limit exceeded (ro) */
283:
284: };
285: #ifdef __FreeBSD__
286:
287: /*
288: * sysctl identifiers underneath kern.ntp_pll
289: */
290: #define NTP_PLL_GETTIME 1 /* used by ntp_gettime() */
291: #define NTP_PLL_MAXID 2 /* number of valid ids */
292:
293: #define NTP_PLL_NAMES { \
294: { 0, 0 }, \
295: { "gettime", CTLTYPE_STRUCT }, \
296: }
297:
298: #ifndef KERNEL
299: #include <sys/cdefs.h>
300:
301: __BEGIN_DECLS
302: extern int ntp_gettime __P((struct ntptimeval *));
303: extern int ntp_adjtime __P((struct timex *));
304: __END_DECLS
305:
306: #endif /* not KERNEL */
307:
308: #endif /* __FreeBSD__ */
309: #endif /* _SYS_TIMEX_H_ */
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