Annotation of embedaddon/ntp/kernel/sys/timex.h, revision 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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