155 lines
5.9 KiB
C
155 lines
5.9 KiB
C
/******************************************************************************
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* *
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* Copyright (c) David L. Mills 1993, 1994 *
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* *
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* Permission to use, copy, modify, and distribute this software and its *
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* documentation for any purpose and without fee is hereby granted, provided *
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* that the above copyright notice appears in all copies and that both the *
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* copyright notice and this permission notice appear in supporting *
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* documentation, and that the name University of Delaware not be used in *
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* advertising or publicity pertaining to distribution of the software *
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* without specific, written prior permission. The University of Delaware *
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* makes no representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied warranty. *
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* *
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******************************************************************************/
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/*
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* Modification history timex.h
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*
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* 20 Feb 94 David L. Mills
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* Revised status codes and structures for external clock and PPS
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* signal discipline.
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*
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* 28 Nov 93 David L. Mills
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* Adjusted parameters to improve stability and increase poll
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* interval.
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*
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* 17 Sep 93 David L. Mills
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* Created file
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*/
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/*
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* This header file defines the Network Time Protocol (NTP) interfaces
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* for user and daemon application programs. These are implemented using
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* private syscalls and data structures and require specific kernel
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* support.
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*
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* NAME
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* ntp_gettime - NTP user application interface
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*
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* SYNOPSIS
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* #include <sys/timex.h>
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*
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* int syscall(SYS_ntp_gettime, tptr)
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*
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* int SYS_ntp_gettime defined in syscall.h header file
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* struct ntptimeval *tptr pointer to ntptimeval structure
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*
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* NAME
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* ntp_adjtime - NTP daemon application interface
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*
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* SYNOPSIS
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* #include <sys/timex.h>
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*
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* int syscall(SYS_ntp_adjtime, mode, tptr)
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*
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* int SYS_ntp_adjtime defined in syscall.h header file
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* struct timex *tptr pointer to timex structure
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*
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*/
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#include <sys/syscall.h>
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/*
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* The following defines establish the engineering parameters of the PLL
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* model. The hz variable is defined in the kernel build environment. It
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* establishes the timer interrupt frequency, 100 Hz for the SunOS
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* kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the OSF/1
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* kernel. The SHIFT_HZ define expresses the same value as the nearest
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* power of two in order to avoid hardware multiply operations.
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*/
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#define SHIFT_HZ 7 /* log2(hz) */
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/*
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* The SHIFT_KG and SHIFT_KF defines establish the damping of the PLL
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* and are chosen by analysis for a slightly underdamped convergence
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* characteristic. The MAXTC define establishes the maximum time
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* constant of the PLL. With the parameters given and the minimum time
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* constant of zero, the PLL will converge in about 15 minutes.
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*/
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#define SHIFT_KG 6 /* phase factor (shift) */
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#define SHIFT_KF 16 /* frequency factor (shift) */
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#define MAXTC 6 /* maximum time constant (shift) */
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/*
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* SHIFT_SCALE defines the scaling (shift) of the time_phase variable,
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* which serves as a an extension to the low-order bits of the system
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* clock variable time.tv_usec. SHIFT_UPDATE defines the scaling (shift)
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* of the time_offset variable, which represents the current time offset
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* with respect to standard time. SHIFT_USEC defines the scaling (shift)
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* of the time_freq and time_tolerance variables, which represent the
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* current frequency offset and frequency tolerance. FINEUSEC is 1 us in
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* SHIFT_UPDATE units of the time_phase variable.
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*/
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#define SHIFT_SCALE 23 /* phase scale (shift) */
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#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
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#define SHIFT_USEC 16 /* frequency offset scale (shift) */
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#define FINEUSEC (1 << SHIFT_SCALE) /* 1 us in phase units */
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/*
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* Mode codes (timex.mode)
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*/
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#define ADJ_OFFSET 0x0001 /* time offset */
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#define ADJ_FREQUENCY 0x0002 /* frequency offset */
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#define ADJ_MAXERROR 0x0004 /* maximum time error */
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#define ADJ_ESTERROR 0x0008 /* estimated time error */
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#define ADJ_STATUS 0x0010 /* clock status */
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#define ADJ_TIMECONST 0x0020 /* pll time constant */
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/*
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* Clock command/status codes (timex.status)
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*/
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#define TIME_OK 0 /* clock synchronized */
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#define TIME_INS 1 /* insert leap second */
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#define TIME_DEL 2 /* delete leap second */
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#define TIME_OOP 3 /* leap second in progress */
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#define TIME_BAD 4 /* kernel clock not synchronized */
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#define TIME_ERR 5 /* external clock not synchronized */
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/*
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* NTP user interface - used to read kernel clock values
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* Note: maximum error = NTP synch distance = dispersion + delay / 2;
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* estimated error = NTP dispersion.
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*/
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struct ntptimeval {
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struct timeval time; /* current time */
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long maxerror; /* maximum error (us) */
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long esterror; /* estimated error (us) */
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};
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/*
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* NTP daemon interface - used to discipline kernel clock oscillator
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*/
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struct timex {
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int mode; /* mode selector */
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long offset; /* time offset (us) */
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long frequency; /* frequency offset (scaled ppm) */
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long maxerror; /* maximum error (us) */
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long esterror; /* estimated error (us) */
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int status; /* clock command/status */
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long time_constant; /* pll time constant */
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long precision; /* clock precision (us) (read only) */
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long tolerance; /* clock frequency tolerance (scaled
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* ppm) (read only) */
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/*
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* The following read-only structure members are implemented
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* only if the PPS signal discipline is configured in the
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* kernel.
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*/
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long ybar; /* frequency estimate (scaled ppm) */
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long disp; /* dispersion estimate (scaled ppm) */
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int shift; /* interval duration (s) (shift) */
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long calcnt; /* calibration intervals */
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long jitcnt; /* jitter limit exceeded */
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long discnt; /* dispersion limit exceeded */
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};
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