142 lines
5.8 KiB
C
142 lines
5.8 KiB
C
/*****************************************************************************
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* *
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* Copyright (c) David L. Mills 1993 *
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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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* 17 Sep 93 David L. Mills
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* Created file $NTP/include/sys/timex.h
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* 07 Oct 93 Torsten Duwe
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* Derived linux/timex.h
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*/
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#ifndef _LINUX_TIMEX_H
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#define _LINUX_TIMEX_H
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#include <linux/unistd.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 establishes the timer interrupt frequency, 100 Hz
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* for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the
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* OSF/1 kernel. The SHIFT_HZ define expresses the same value as the
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* nearest 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 constant
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* of the PLL. With the parameters given and the default time constant of
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* zero, the PLL will converge in about 15 minutes.
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*/
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#define SHIFT_KG 8 /* shift for phase increment */
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#define SHIFT_KF 20 /* shift for frequency increment */
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#define MAXTC 6 /* maximum time constant (shift) */
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/*
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* The SHIFT_SCALE define establishes the decimal point of the time_phase
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* variable which serves as a an extension to the low-order bits of the
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* system clock variable. The SHIFT_UPDATE define establishes the decimal
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* point of the time_offset variable which represents the current offset
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* with respect to standard time. The FINEUSEC define represents 1 usec in
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* scaled units.
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*/
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#define SHIFT_SCALE 24 /* shift for phase scale factor */
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#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* shift for offset scale factor */
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#define FINEUSEC (1 << SHIFT_SCALE) /* 1 us in scaled units */
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#define MAXPHASE 128000 /* max phase error (us) */
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#define MAXFREQ 100 /* max frequency error (ppm) */
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#define MINSEC 16 /* min interval between updates (s) */
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#define MAXSEC 1200 /* max interval between updates (s) */
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#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
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#define CLOCK_TICK_FACTOR 20 /* Factor of both 1000000 and CLOCK_TICK_RATE */
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#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
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#define FINETUNE (((((LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \
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(1000000/CLOCK_TICK_FACTOR) / (CLOCK_TICK_RATE/CLOCK_TICK_FACTOR)) \
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<< (SHIFT_SCALE-SHIFT_HZ)) / HZ)
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/*
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* syscall interface - used (mainly by NTP daemon)
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* 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 (usec) */
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long frequency; /* frequency offset (scaled ppm) */
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long maxerror; /* maximum error (usec) */
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long esterror; /* estimated error (usec) */
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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 (usec) (read only) */
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long tolerance; /* clock frequency tolerance (ppm)
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* (read only)
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*/
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struct timeval time; /* (read only) */
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long tick; /* (modified) usecs between clock ticks */
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};
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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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#define ADJ_TICK 0x4000 /* tick value */
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#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
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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 /* clock not synchronized */
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#ifdef __KERNEL__
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/*
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* kernel variables
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*/
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extern long tick; /* timer interrupt period */
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extern int tickadj; /* amount of adjustment per tick */
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extern volatile struct timeval xtime; /* The current time */
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/*
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* phase-lock loop variables
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*/
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extern int time_status; /* clock synchronization status */
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extern long time_offset; /* time adjustment (us) */
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extern long time_constant; /* pll time constant */
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extern long time_tolerance; /* frequency tolerance (ppm) */
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extern long time_precision; /* clock precision (us) */
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extern long time_maxerror; /* maximum error */
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extern long time_esterror; /* estimated error */
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extern long time_phase; /* phase offset (scaled us) */
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extern long time_freq; /* frequency offset (scaled ppm) */
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extern long time_adj; /* tick adjust (scaled 1 / HZ) */
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extern long time_reftime; /* time at last adjustment (s) */
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extern long time_adjust; /* The amount of adjtime left */
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#endif /* KERNEL */
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#endif /* LINUX_TIMEX_H */
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