/******************************************************************************
* *
* Copyright (c) David L. Mills 1993, 1994 *
* *
* Permission to use, copy, modify, and distribute this software and its *
* documentation for any purpose and without fee is hereby granted, provided *
* that the above copyright notice appears in all copies and that both the *
* copyright notice and this permission notice appear in supporting *
* documentation, and that the name University of Delaware not be used in *
* advertising or publicity pertaining to distribution of the software *
* without specific, written prior permission. The University of Delaware *
* makes no representations about the suitability this software for any *
* purpose. It is provided "as is" without express or implied warranty. *
* *
******************************************************************************/
/*
* Modification history timex.h
*
* 19 Mar 94 David L. Mills
* Moved defines from kernel routines to header file and added new
* defines for PPS phase-lock loop.
*
* 20 Feb 94 David L. Mills
* Revised status codes and structures for external clock and PPS
* signal discipline.
*
* 28 Nov 93 David L. Mills
* Adjusted parameters to improve stability and increase poll
* interval.
*
* 17 Sep 93 David L. Mills
* Created file
*/
/*
* This header file defines the Network Time Protocol (NTP) interfaces
* for user and daemon application programs. These are implemented using
* private syscalls and data structures and require specific kernel
* support.
*
* NAME
* ntp_gettime - NTP user application interface
*
* SYNOPSIS
* #include <sys/timex.h>
*
* int syscall(SYS_ntp_gettime, tptr)
*
* int SYS_ntp_gettime defined in syscall.h header file
* struct ntptimeval *tptr pointer to ntptimeval structure
*
* NAME
* ntp_adjtime - NTP daemon application interface
*
* SYNOPSIS
* #include <sys/timex.h>
*
* int syscall(SYS_ntp_adjtime, mode, tptr)
*
* int SYS_ntp_adjtime defined in syscall.h header file
* struct timex *tptr pointer to timex structure
*
*/
#ifndef _FREEBSD_TIMEX_H
#define _FREEBSD_TIMEX_H 1
#ifndef MSDOS /* Microsoft specific */
#include <sys/syscall.h>
#endif /* MSDOS */
/*
* The following defines establish the engineering parameters of the
* phase-lock loop (PLL) model used in the kernel implementation. These
* parameters have been carefully chosen by analysis for good stability
* and wide dynamic range.
*
* The hz variable is defined in the kernel build environment. It
* establishes the timer interrupt frequency, 100 Hz for the SunOS
* kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the OSF/1
* kernel. SHIFT_HZ expresses the same value as the nearest power of two
* in order to avoid hardware multiply operations.
*
* SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
* for a slightly underdamped convergence characteristic.
*
* MAXTC establishes the maximum time constant of the PLL. With the
* SHIFT_KG and SHIFT_KF values given and a time constant range from
* zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
* respectively.
*/
#define SHIFT_HZ 7 /* log2(hz) */
#define SHIFT_KG 6 /* phase factor (shift) */
#define SHIFT_KF 16 /* frequency factor (shift) */
#define MAXTC 6 /* maximum time constant (shift) */
/*
* The following defines establish the scaling of the various variables
* used by the PLL. They are chosen to allow the greatest precision
* possible without overflow of a 32-bit word.
*
* SHIFT_SCALE defines the scaling (shift) of the time_phase variable,
* which serves as a an extension to the low-order bits of the system
* clock variable time.tv_usec.
*
* SHIFT_UPDATE defines the scaling (shift) of the time_offset variable,
* which represents the current time offset with respect to standard
* time.
*
* SHIFT_USEC defines the scaling (shift) of the time_freq and
* time_tolerance variables, which represent the current frequency
* offset and maximum frequency tolerance.
*
* FINEUSEC is 1 us in SHIFT_UPDATE units of the time_phase variable.
*/
#define SHIFT_SCALE 23 /* phase scale (shift) */
#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
#define SHIFT_USEC 16 /* frequency offset scale (shift) */
#define FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */
/*
* The following defines establish the performance envelope of the PLL.
* They insure it operates within predefined limits, in order to satisfy
* correctness assertions. An excursion which exceeds these bounds is
* clamped to the bound and operation proceeds accordingly. In practice,
* this can occur only if something has failed or is operating out of
* tolerance, but otherwise the PLL continues to operate in a stable
* mode.
*
* MAXPHASE must be set greater than or equal to CLOCK.MAX (128 ms), as
* defined in the NTP specification. CLOCK.MAX establishes the maximum
* time offset allowed before the system time is reset, rather than
* incrementally adjusted. Here, the maximum offset is clamped to
* MAXPHASE only in order to prevent overflow errors due to defective
* protocol implementations.
*
* MAXFREQ is the maximum frequency tolerance of the CPU clock
* oscillator plus the maximum slew rate allowed by the protocol. It
* should be set to at least the frequency tolerance of the oscillator
* plus 100 ppm for vernier frequency adjustments. If the kernel
* PPS discipline code is configured (PPS_SYNC), the oscillator time and
* frequency are disciplined to an external source, presumably with
* negligible time and frequency error relative to UTC, and MAXFREQ can
* be reduced.
*
* MAXTIME is the maximum jitter tolerance of the PPS signal if the
* kernel PPS discipline code is configured (PPS_SYNC).
*
* MINSEC and MAXSEC define the lower and upper bounds on the interval
* between protocol updates.
*/
#define MAXPHASE 128000L /* max phase error (us) */
#ifdef PPS_SYNC
#define MAXFREQ (100L << SHIFT_USEC) /* max freq error (100 ppm) */
#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
#else
#define MAXFREQ (200L << SHIFT_USEC) /* max freq error (200 ppm) */
#endif /* PPS_SYNC */
#define MINSEC 16L /* min interval between updates (s) */
#define MAXSEC 1200L /* max interval between updates (s) */
#ifdef PPS_SYNC
/*
* The following defines are used only if a pulse-per-second (PPS)
* signal is available and connected via a modem control lead, such as
* produced by the optional ppsclock feature incorporated in the Sun
* asynch driver. They establish the design parameters of the frequency-
* lock loop used to discipline the CPU clock oscillator to the PPS
* signal.
*
* PPS_AVG is the averaging factor for the frequency loop, as well as
* the time and frequency dispersion.
*
* PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
* calibration intervals, respectively, in seconds as a power of two.
*
* PPS_VALID is the maximum interval before the PPS signal is considered
* invalid and protocol updates used directly instead.
*
* MAXGLITCH is the maximum interval before a time offset of more than
* MAXTIME is believed.
*/
#define PPS_AVG 2 /* pps averaging constant (shift) */
#define PPS_SHIFT 2 /* min interval duration (s) (shift) */
#define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
#define PPS_VALID 120 /* pps signal watchdog max (s) */
#define MAXGLITCH 30 /* pps signal glitch max (s) */
#endif /* PPS_SYNC */
/*
* The following defines and structures define the user interface for
* the ntp_gettime() and ntp_adjtime() system calls.
*
* Control mode codes (timex.modes)
*/
#define MOD_OFFSET 0x0001 /* set time offset */
#define MOD_FREQUENCY 0x0002 /* set frequency offset */
#define MOD_MAXERROR 0x0004 /* set maximum time error */
#define MOD_ESTERROR 0x0008 /* set estimated time error */
#define MOD_STATUS 0x0010 /* set clock status bits */
#define MOD_TIMECONST 0x0020 /* set pll time constant */
#define MOD_CLKB 0x4000 /* set clock B */
#define MOD_CLKA 0x8000 /* set clock A */
/*
* Clock states (time_state)
*/
#define TIME_OK 0 /* no leap second warning */
#define TIME_INS 1 /* insert leap second warning */
#define TIME_DEL 2 /* delete leap second warning */
#define TIME_OOP 3 /* leap second in progress */
#define TIME_WAIT 4 /* leap second has occurred */
#define TIME_ERROR 5 /* clock not synchronized */
/*
* NTP user interface (ntp_gettime()) - used to read kernel clock values
*
* Note: maximum error = NTP synch distance = dispersion + delay / 2;
* estimated error = NTP dispersion.
*/
struct freebsd_ntptimeval {
struct timeval time; /* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
int time_state; /* what ntp_gettime returns */
};
/*
* NTP daemon interface - (ntp_adjtime()) used to discipline CPU clock
* oscillator
*/
struct freebsd_timex {
unsigned int modes; /* clock mode bits (wo) */
long offset; /* time offset (us) (rw) */
long freq; /* frequency offset (scaled ppm) (rw) */
long maxerror; /* maximum error (us) (rw) */
long esterror; /* estimated error (us) (rw) */
int status; /* clock status bits (rw) */
long constant; /* pll time constant (rw) */
long precision; /* clock precision (us) (ro) */
long tolerance; /* clock frequency tolerance (scaled
* ppm) (ro) */
/*
* The following read-only structure members are implemented
* only if the PPS signal discipline is configured in the
* kernel.
*/
long ppsfreq; /* pps frequency (scaled ppm) (ro) */
long jitter; /* pps jitter (us) (ro) */
int shift; /* interval duration (s) (shift) (ro) */
long stabil; /* pps stability (scaled ppm) (ro) */
long jitcnt; /* jitter limit exceeded (ro) */
long calcnt; /* calibration intervals (ro) */
long errcnt; /* calibration errors (ro) */
long stbcnt; /* stability limit exceeded (ro) */
};
#ifdef __FreeBSD__
/*
* sysctl identifiers underneath kern.ntp_pll
*/
#define NTP_PLL_GETTIME 1 /* used by ntp_gettime() */
#define NTP_PLL_MAXID 2 /* number of valid ids */
