344 lines
13 KiB
C
344 lines
13 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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* 29 Dec 97 Russell King
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* Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
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* for ARM machines
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*
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* 9 Jan 97 Adrian Sun
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* Shifted LATCH define to allow access to alpha machines.
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*
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* 26 Sep 94 David L. Mills
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* Added defines for hybrid phase/frequency-lock loop.
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*
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* 19 Mar 94 David L. Mills
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* Moved defines from kernel routines to header file and added new
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* defines for PPS phase-lock loop.
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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 $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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* 1995-08-13 Torsten Duwe
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* kernel PLL updated to 1994-12-13 specs (rfc-1589)
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* 1997-08-30 Ulrich Windl
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* Added new constant NTP_PHASE_LIMIT
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* 2004-08-12 Christoph Lameter
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* Reworked time interpolation logic
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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/config.h>
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#include <linux/compiler.h>
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#include <linux/time.h>
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#include <asm/param.h>
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#include <asm/timex.h>
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/*
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* SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
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* for a slightly underdamped convergence characteristic. SHIFT_KH
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* establishes the damping of the FLL and is chosen by wisdom and black
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* art.
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*
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* MAXTC establishes the maximum time constant of the PLL. With the
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* SHIFT_KG and SHIFT_KF values given and a time constant range from
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* zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
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* respectively.
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*/
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#define SHIFT_KG 6 /* phase factor (shift) */
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#define SHIFT_KF 16 /* PLL frequency factor (shift) */
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#define SHIFT_KH 2 /* FLL frequency factor (shift) */
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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 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 FINENSEC define represents 1 nsec in
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* scaled units.
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*
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* SHIFT_USEC defines the scaling (shift) of the time_freq and
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* time_tolerance variables, which represent the current frequency
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* offset and maximum frequency tolerance.
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*
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* FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable.
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*/
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#define SHIFT_SCALE 22 /* 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 FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */
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#define MAXPHASE 512000L /* max phase error (us) */
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#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
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#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */
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#define MINSEC 16L /* min interval between updates (s) */
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#define MAXSEC 1200L /* max interval between updates (s) */
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#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
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/*
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* The following defines are used only if a pulse-per-second (PPS)
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* signal is available and connected via a modem control lead, such as
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* produced by the optional ppsclock feature incorporated in the Sun
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* asynch driver. They establish the design parameters of the frequency-
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* lock loop used to discipline the CPU clock oscillator to the PPS
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* signal.
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*
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* PPS_AVG is the averaging factor for the frequency loop, as well as
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* the time and frequency dispersion.
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*
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* PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum
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* calibration intervals, respectively, in seconds as a power of two.
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*
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* PPS_VALID is the maximum interval before the PPS signal is considered
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* invalid and protocol updates used directly instead.
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*
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* MAXGLITCH is the maximum interval before a time offset of more than
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* MAXTIME is believed.
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*/
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#define PPS_AVG 2 /* pps averaging constant (shift) */
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#define PPS_SHIFT 2 /* min interval duration (s) (shift) */
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#define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */
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#define PPS_VALID 120 /* pps signal watchdog max (s) */
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#define MAXGLITCH 30 /* pps signal glitch max (s) */
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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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unsigned int modes; /* mode selector */
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long offset; /* time offset (usec) */
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long freq; /* 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 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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long ppsfreq; /* pps frequency (scaled ppm) (ro) */
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long jitter; /* pps jitter (us) (ro) */
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int shift; /* interval duration (s) (shift) (ro) */
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long stabil; /* pps stability (scaled ppm) (ro) */
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long jitcnt; /* jitter limit exceeded (ro) */
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long calcnt; /* calibration intervals (ro) */
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long errcnt; /* calibration errors (ro) */
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long stbcnt; /* stability limit exceeded (ro) */
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int :32; int :32; int :32; int :32;
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int :32; int :32; int :32; int :32;
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int :32; int :32; int :32; int :32;
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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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/* xntp 3.4 compatibility names */
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#define MOD_OFFSET ADJ_OFFSET
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#define MOD_FREQUENCY ADJ_FREQUENCY
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#define MOD_MAXERROR ADJ_MAXERROR
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#define MOD_ESTERROR ADJ_ESTERROR
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#define MOD_STATUS ADJ_STATUS
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#define MOD_TIMECONST ADJ_TIMECONST
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#define MOD_CLKB ADJ_TICK
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#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
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/*
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* Status codes (timex.status)
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*/
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#define STA_PLL 0x0001 /* enable PLL updates (rw) */
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#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
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#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
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#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
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#define STA_INS 0x0010 /* insert leap (rw) */
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#define STA_DEL 0x0020 /* delete leap (rw) */
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#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
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#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
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#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
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#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
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#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
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#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
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#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
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#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
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STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
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/*
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* Clock states (time_state)
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*/
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#define TIME_OK 0 /* clock synchronized, no leap second */
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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_WAIT 4 /* leap second has occurred */
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#define TIME_ERROR 5 /* clock not synchronized */
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#define TIME_BAD TIME_ERROR /* bw compat */
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#ifdef __KERNEL__
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/*
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* kernel variables
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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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extern unsigned long tick_usec; /* USER_HZ period (usec) */
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extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
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extern int tickadj; /* amount of adjustment per tick */
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/*
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* phase-lock loop variables
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*/
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extern int time_state; /* clock status */
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extern int time_status; /* clock synchronization status bits */
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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_freq; /* frequency offset (scaled ppm) */
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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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extern long time_next_adjust; /* Value for time_adjust at next tick */
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/* interface variables pps->timer interrupt */
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extern long pps_offset; /* pps time offset (us) */
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extern long pps_jitter; /* time dispersion (jitter) (us) */
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extern long pps_freq; /* frequency offset (scaled ppm) */
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extern long pps_stabil; /* frequency dispersion (scaled ppm) */
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extern long pps_valid; /* pps signal watchdog counter */
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/* interface variables pps->adjtimex */
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extern int pps_shift; /* interval duration (s) (shift) */
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extern long pps_jitcnt; /* jitter limit exceeded */
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extern long pps_calcnt; /* calibration intervals */
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extern long pps_errcnt; /* calibration errors */
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extern long pps_stbcnt; /* stability limit exceeded */
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/**
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* ntp_clear - Clears the NTP state variables
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*
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* Must be called while holding a write on the xtime_lock
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*/
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static inline void ntp_clear(void)
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{
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time_adjust = 0; /* stop active adjtime() */
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time_status |= STA_UNSYNC;
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time_maxerror = NTP_PHASE_LIMIT;
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time_esterror = NTP_PHASE_LIMIT;
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}
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/**
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* ntp_synced - Returns 1 if the NTP status is not UNSYNC
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*
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*/
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static inline int ntp_synced(void)
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{
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return !(time_status & STA_UNSYNC);
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}
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#ifdef CONFIG_TIME_INTERPOLATION
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#define TIME_SOURCE_CPU 0
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#define TIME_SOURCE_MMIO64 1
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#define TIME_SOURCE_MMIO32 2
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#define TIME_SOURCE_FUNCTION 3
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/* For proper operations time_interpolator clocks must run slightly slower
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* than the standard clock since the interpolator may only correct by having
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* time jump forward during a tick. A slower clock is usually a side effect
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* of the integer divide of the nanoseconds in a second by the frequency.
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* The accuracy of the division can be increased by specifying a shift.
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* However, this may cause the clock not to be slow enough.
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* The interpolator will self-tune the clock by slowing down if no
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* resets occur or speeding up if the time jumps per analysis cycle
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* become too high.
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*
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* Setting jitter compensates for a fluctuating timesource by comparing
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* to the last value read from the timesource to insure that an earlier value
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* is not returned by a later call. The price to pay
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* for the compensation is that the timer routines are not as scalable anymore.
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*/
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struct time_interpolator {
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u16 source; /* time source flags */
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u8 shift; /* increases accuracy of multiply by shifting. */
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/* Note that bits may be lost if shift is set too high */
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u8 jitter; /* if set compensate for fluctuations */
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u32 nsec_per_cyc; /* set by register_time_interpolator() */
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void *addr; /* address of counter or function */
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u64 mask; /* mask the valid bits of the counter */
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unsigned long offset; /* nsec offset at last update of interpolator */
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u64 last_counter; /* counter value in units of the counter at last update */
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u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */
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u64 frequency; /* frequency in counts/second */
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long drift; /* drift in parts-per-million (or -1) */
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unsigned long skips; /* skips forward */
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unsigned long ns_skipped; /* nanoseconds skipped */
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struct time_interpolator *next;
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};
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extern void register_time_interpolator(struct time_interpolator *);
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extern void unregister_time_interpolator(struct time_interpolator *);
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extern void time_interpolator_reset(void);
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extern unsigned long time_interpolator_get_offset(void);
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#else /* !CONFIG_TIME_INTERPOLATION */
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static inline void
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time_interpolator_reset(void)
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{
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}
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#endif /* !CONFIG_TIME_INTERPOLATION */
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#endif /* KERNEL */
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#endif /* LINUX_TIMEX_H */
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