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/*****************************************************************************
* *
* Copyright (c) David L. Mills 1993 *
* *
* 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
*
* 17 Sep 93 David L. Mills
* Created file $NTP/include/sys/timex.h
* 07 Oct 93 Torsten Duwe
* Derived linux/timex.h
*/
#ifndef _LINUX_TIMEX_H
#define _LINUX_TIMEX_H
/*
* The following defines establish the engineering parameters of the PLL
* model. The HZ variable 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. The SHIFT_HZ define expresses the same value as the
* nearest power of two in order to avoid hardware multiply operations.
*/
#define SHIFT_HZ 7 /* log2(HZ) */
/*
* The SHIFT_KG and SHIFT_KF defines establish the damping of the PLL
* and are chosen by analysis for a slightly underdamped convergence
* characteristic. The MAXTC define establishes the maximum time constant
* of the PLL. With the parameters given and the default time constant of
* zero, the PLL will converge in about 15 minutes.
*/
#define SHIFT_KG 8 /* shift for phase increment */
#define SHIFT_KF 20 /* shift for frequency increment */
#define MAXTC 6 /* maximum time constant (shift) */
/*
* The SHIFT_SCALE define establishes the decimal point of the time_phase
* variable which serves as a an extension to the low-order bits of the
* system clock variable. The SHIFT_UPDATE define establishes the decimal
* point of the time_offset variable which represents the current offset
* with respect to standard time. The FINEUSEC define represents 1 usec in
* scaled units.
*/
#define SHIFT_SCALE 24 /* shift for phase scale factor */
#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* shift for offset scale factor */
#define FINEUSEC (1 << SHIFT_SCALE) /* 1 us in scaled units */
#define MAXPHASE 128000 /* max phase error (us) */
#define MAXFREQ 100 /* max frequency error (ppm) */
#define MINSEC 16 /* min interval between updates (s) */
#define MAXSEC 1200 /* max interval between updates (s) */
#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
#define CLOCK_TICK_FACTOR 20 /* Factor of both 1000000 and CLOCK_TICK_RATE */
#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
#define FINETUNE (((((LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \
(1000000/CLOCK_TICK_FACTOR) / (CLOCK_TICK_RATE/CLOCK_TICK_FACTOR)) \
<< (SHIFT_SCALE-SHIFT_HZ)) / HZ)
/*
* syscall interface - used (mainly by NTP daemon)
* to discipline kernel clock oscillator
*/
struct timex {
int mode; /* mode selector */
long offset; /* time offset (usec) */
long frequency; /* frequency offset (scaled ppm) */
long maxerror; /* maximum error (usec) */
long esterror; /* estimated error (usec) */
int status; /* clock command/status */
long time_constant; /* pll time constant */
long precision; /* clock precision (usec) (read only) */
long tolerance; /* clock frequency tolerance (ppm)
* (read only)
*/
struct timeval time; /* (read only) */
long tick; /* (modified) usecs between clock ticks */
};
/*
* Mode codes (timex.mode)
*/
#define ADJ_OFFSET 0x0001 /* time offset */
#define ADJ_FREQUENCY 0x0002 /* frequency offset */
#define ADJ_MAXERROR 0x0004 /* maximum time error */
#define ADJ_ESTERROR 0x0008 /* estimated time error */
#define ADJ_STATUS 0x0010 /* clock status */
#define ADJ_TIMECONST 0x0020 /* pll time constant */
#define ADJ_TICK 0x4000 /* tick value */
#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
/*
* Clock command/status codes (timex.status)
*/
#define TIME_OK 0 /* clock synchronized */
#define TIME_INS 1 /* insert leap second */
#define TIME_DEL 2 /* delete leap second */
#define TIME_OOP 3 /* leap second in progress */
#define TIME_BAD 4 /* clock not synchronized */
#ifdef __KERNEL__
/*
* kernel variables
*/
extern long tick; /* timer interrupt period */
extern int tickadj; /* amount of adjustment per tick */
/*
* phase-lock loop variables
*/
extern int time_status; /* clock synchronization status */
extern long time_offset; /* time adjustment (us) */
extern long time_constant; /* pll time constant */
extern long time_tolerance; /* frequency tolerance (ppm) */
extern long time_precision; /* clock precision (us) */
extern long time_maxerror; /* maximum error */
extern long time_esterror; /* estimated error */
extern long time_phase; /* phase offset (scaled us) */
extern long time_freq; /* frequency offset (scaled ppm) */
extern long time_adj; /* tick adjust (scaled 1 / HZ) */
extern long time_reftime; /* time at last adjustment (s) */
extern long time_adjust; /* The amount of adjtime left */
#endif /* KERNEL */
#endif /* LINUX_TIMEX_H */
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