include/linux/timex.h - kernel/msm-4.9 - Gitiles

 /*****************************************************************************
  *                                                                           *
  * 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
  *
  * 29 Dec 97	Russell King
  *	Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
  *	for ARM machines
  *
  *  9 Jan 97    Adrian Sun
  *      Shifted LATCH define to allow access to alpha machines.
  *
  * 26 Sep 94	David L. Mills
  *	Added defines for hybrid phase/frequency-lock loop.
  *
  * 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 $NTP/include/sys/timex.h
  * 07 Oct 93    Torsten Duwe
  *      Derived linux/timex.h
  * 1995-08-13    Torsten Duwe
  *      kernel PLL updated to 1994-12-13 specs (rfc-1589)
  * 1997-08-30    Ulrich Windl
  *      Added new constant NTP_PHASE_LIMIT
  * 2004-08-12    Christoph Lameter
  *      Reworked time interpolation logic
  */
 #ifndef _LINUX_TIMEX_H
 #define _LINUX_TIMEX_H

 #include <linux/time.h>

 #define NTP_API		4	/* NTP API version */

 /*
  * syscall interface - used (mainly by NTP daemon)
  * to discipline kernel clock oscillator
  */
 struct timex {
 	unsigned int modes;	/* mode selector */
 	long offset;		/* time offset (usec) */
 	long freq;		/* frequency offset (scaled ppm) */
 	long maxerror;		/* maximum error (usec) */
 	long esterror;		/* estimated error (usec) */
 	int status;		/* clock command/status */
 	long 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 */

 	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) */

 	int tai;		/* TAI offset (ro) */

 	int  :32; int  :32; int  :32; int  :32;
 	int  :32; int  :32; int  :32; int  :32;
 	int  :32; int  :32; int  :32;
 };

 /*
  * 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_TAI			0x0080	/* set TAI offset */
 #define ADJ_MICRO		0x1000	/* select microsecond resolution */
 #define ADJ_NANO		0x2000	/* select nanosecond resolution */
 #define ADJ_TICK		0x4000	/* tick value */

 #ifdef __KERNEL__
 #define ADJ_ADJTIME		0x8000	/* switch between adjtime/adjtimex modes */
 #define ADJ_OFFSET_SINGLESHOT	0x0001	/* old-fashioned adjtime */
 #define ADJ_OFFSET_READONLY	0x2000	/* read-only adjtime */
 #else
 #define ADJ_OFFSET_SINGLESHOT	0x8001	/* old-fashioned adjtime */
 #define ADJ_OFFSET_SS_READ	0xa001	/* read-only adjtime */
 #endif

 /* NTP userland likes the MOD_ prefix better */
 #define MOD_OFFSET	ADJ_OFFSET
 #define MOD_FREQUENCY	ADJ_FREQUENCY
 #define MOD_MAXERROR	ADJ_MAXERROR
 #define MOD_ESTERROR	ADJ_ESTERROR
 #define MOD_STATUS	ADJ_STATUS
 #define MOD_TIMECONST	ADJ_TIMECONST
 #define MOD_TAI	ADJ_TAI
 #define MOD_MICRO	ADJ_MICRO
 #define MOD_NANO	ADJ_NANO


 /*
  * Status codes (timex.status)
  */
 #define STA_PLL		0x0001	/* enable PLL updates (rw) */
 #define STA_PPSFREQ	0x0002	/* enable PPS freq discipline (rw) */
 #define STA_PPSTIME	0x0004	/* enable PPS time discipline (rw) */
 #define STA_FLL		0x0008	/* select frequency-lock mode (rw) */

 #define STA_INS		0x0010	/* insert leap (rw) */
 #define STA_DEL		0x0020	/* delete leap (rw) */
 #define STA_UNSYNC	0x0040	/* clock unsynchronized (rw) */
 #define STA_FREQHOLD	0x0080	/* hold frequency (rw) */

 #define STA_PPSSIGNAL	0x0100	/* PPS signal present (ro) */
 #define STA_PPSJITTER	0x0200	/* PPS signal jitter exceeded (ro) */
 #define STA_PPSWANDER	0x0400	/* PPS signal wander exceeded (ro) */
 #define STA_PPSERROR	0x0800	/* PPS signal calibration error (ro) */

 #define STA_CLOCKERR	0x1000	/* clock hardware fault (ro) */
 #define STA_NANO	0x2000	/* resolution (0 = us, 1 = ns) (ro) */
 #define STA_MODE	0x4000	/* mode (0 = PLL, 1 = FLL) (ro) */
 #define STA_CLK		0x8000	/* clock source (0 = A, 1 = B) (ro) */

 /* read-only bits */
 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
 	STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)

 /*
  * Clock states (time_state)
  */
 #define TIME_OK		0	/* clock synchronized, no leap second */
 #define TIME_INS	1	/* insert leap second */
 #define TIME_DEL	2	/* delete leap second */
 #define TIME_OOP	3	/* leap second in progress */
 #define TIME_WAIT	4	/* leap second has occurred */
 #define TIME_ERROR	5	/* clock not synchronized */
 #define TIME_BAD	TIME_ERROR /* bw compat */

 #ifdef __KERNEL__
 #include <linux/compiler.h>
 #include <linux/types.h>
 #include <linux/param.h>

 #include <asm/timex.h>

 /*
  * SHIFT_PLL is used as a dampening factor to define how much we
  * adjust the frequency correction for a given offset in PLL mode.
  * It also used in dampening the offset correction, to define how
  * much of the current value in time_offset we correct for each
  * second. Changing this value changes the stiffness of the ntp
  * adjustment code. A lower value makes it more flexible, reducing
  * NTP convergence time. A higher value makes it stiffer, increasing
  * convergence time, but making the clock more stable.
  *
  * In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
  * However this seems to increase convergence time much too long.
  *
  * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
  *
  * In the above mailing list discussion, it seems the value of 4
  * was appropriate for other Unix systems with HZ=100, and that
  * SHIFT_PLL should be decreased as HZ increases. However, Linux's
  * clock steering implementation is HZ independent.
  *
  * Through experimentation, a SHIFT_PLL value of 2 was found to allow
  * for fast convergence (very similar to the NTPv3 code used prior to
  * v2.6.19), with good clock stability.
  *
  *
  * SHIFT_FLL is used as a dampening factor to define how much we
  * adjust the frequency correction for a given offset in FLL mode.
  * In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
  *
  * MAXTC establishes the maximum time constant of the PLL.
  */
 #define SHIFT_PLL	2	/* PLL frequency factor (shift) */
 #define SHIFT_FLL	2	/* FLL frequency factor (shift) */
 #define MAXTC		10	/* maximum time constant (shift) */

 /*
  * SHIFT_USEC defines the scaling (shift) of the time_freq and
  * time_tolerance variables, which represent the current frequency
  * offset and maximum frequency tolerance.
  */
 #define SHIFT_USEC 16		/* frequency offset scale (shift) */
 #define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
 #define PPM_SCALE_INV_SHIFT 19
 #define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
 		       PPM_SCALE + 1)

 #define MAXPHASE 500000000L	/* max phase error (ns) */
 #define MAXFREQ 500000		/* max frequency error (ns/s) */
 #define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
 #define MINSEC 256		/* min interval between updates (s) */
 #define MAXSEC 2048		/* max interval between updates (s) */
 #define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */

 /*
  * kernel variables
  * Note: maximum error = NTP synch distance = dispersion + delay / 2;
  * estimated error = NTP dispersion.
  */
 extern unsigned long tick_usec;		/* USER_HZ period (usec) */
 extern unsigned long tick_nsec;		/* ACTHZ          period (nsec) */
 extern int tickadj;			/* amount of adjustment per tick */

 /*
  * phase-lock loop variables
  */
 extern int time_status;		/* clock synchronization status bits */
 extern long time_adjust;	/* The amount of adjtime left */

 extern void ntp_init(void);
 extern void ntp_clear(void);

 /**
  * ntp_synced - Returns 1 if the NTP status is not UNSYNC
  *
  */
 static inline int ntp_synced(void)
 {
 	return !(time_status & STA_UNSYNC);
 }

 /* Required to safely shift negative values */
 #define shift_right(x, s) ({	\
 	__typeof__(x) __x = (x);	\
 	__typeof__(s) __s = (s);	\
 	__x < 0 ? -(-__x >> __s) : __x >> __s;	\
 })

 #define NTP_SCALE_SHIFT		32

 #define NTP_INTERVAL_FREQ  (HZ)
 #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)

 /* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
 extern u64 tick_length;

 extern void second_overflow(void);
 extern void update_ntp_one_tick(void);
 extern int do_adjtimex(struct timex *);

 /* Don't use! Compatibility define for existing users. */
 #define tickadj	(500/HZ ? : 1)

 int read_current_timer(unsigned long *timer_val);

 /* The clock frequency of the i8253/i8254 PIT */
 #define PIT_TICK_RATE 1193182ul

 #endif /* KERNEL */

 #endif /* LINUX_TIMEX_H */
	/*****************************************************************************
	* *
	* 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
	*
	* 29 Dec 97 Russell King
	* Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
	* for ARM machines
	*
	* 9 Jan 97 Adrian Sun
	* Shifted LATCH define to allow access to alpha machines.
	*
	* 26 Sep 94 David L. Mills
	* Added defines for hybrid phase/frequency-lock loop.
	*
	* 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 $NTP/include/sys/timex.h
	* 07 Oct 93 Torsten Duwe
	* Derived linux/timex.h
	* 1995-08-13 Torsten Duwe
	* kernel PLL updated to 1994-12-13 specs (rfc-1589)
	* 1997-08-30 Ulrich Windl
	* Added new constant NTP_PHASE_LIMIT
	* 2004-08-12 Christoph Lameter
	* Reworked time interpolation logic
	*/
	#ifndef _LINUX_TIMEX_H
	#define _LINUX_TIMEX_H

	#include <linux/time.h>

	#define NTP_API 4 /* NTP API version */

	/*
	* syscall interface - used (mainly by NTP daemon)
	* to discipline kernel clock oscillator
	*/
	struct timex {
	unsigned int modes; /* mode selector */
	long offset; /* time offset (usec) */
	long freq; /* frequency offset (scaled ppm) */
	long maxerror; /* maximum error (usec) */
	long esterror; /* estimated error (usec) */
	int status; /* clock command/status */
	long 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 */

	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) */

	int tai; /* TAI offset (ro) */

	int :32; int :32; int :32; int :32;
	int :32; int :32; int :32; int :32;
	int :32; int :32; int :32;
	};

	/*
	* 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_TAI 0x0080 /* set TAI offset */
	#define ADJ_MICRO 0x1000 /* select microsecond resolution */
	#define ADJ_NANO 0x2000 /* select nanosecond resolution */
	#define ADJ_TICK 0x4000 /* tick value */

	#ifdef __KERNEL__
	#define ADJ_ADJTIME 0x8000 /* switch between adjtime/adjtimex modes */
	#define ADJ_OFFSET_SINGLESHOT 0x0001 /* old-fashioned adjtime */
	#define ADJ_OFFSET_READONLY 0x2000 /* read-only adjtime */
	#else
	#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
	#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
	#endif

	/* NTP userland likes the MOD_ prefix better */
	#define MOD_OFFSET ADJ_OFFSET
	#define MOD_FREQUENCY ADJ_FREQUENCY
	#define MOD_MAXERROR ADJ_MAXERROR
	#define MOD_ESTERROR ADJ_ESTERROR
	#define MOD_STATUS ADJ_STATUS
	#define MOD_TIMECONST ADJ_TIMECONST
	#define MOD_TAI ADJ_TAI
	#define MOD_MICRO ADJ_MICRO
	#define MOD_NANO ADJ_NANO


	/*
	* Status codes (timex.status)
	*/
	#define STA_PLL 0x0001 /* enable PLL updates (rw) */
	#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
	#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
	#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */

	#define STA_INS 0x0010 /* insert leap (rw) */
	#define STA_DEL 0x0020 /* delete leap (rw) */
	#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
	#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */

	#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
	#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
	#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
	#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */

	#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
	#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
	#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
	#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */

	/* read-only bits */
	#define STA_RONLY (STA_PPSSIGNAL \| STA_PPSJITTER \| STA_PPSWANDER \| \
	STA_PPSERROR \| STA_CLOCKERR \| STA_NANO \| STA_MODE \| STA_CLK)

	/*
	* Clock states (time_state)
	*/
	#define TIME_OK 0 /* clock synchronized, no leap second */
	#define TIME_INS 1 /* insert leap second */
	#define TIME_DEL 2 /* delete leap second */
	#define TIME_OOP 3 /* leap second in progress */
	#define TIME_WAIT 4 /* leap second has occurred */
	#define TIME_ERROR 5 /* clock not synchronized */
	#define TIME_BAD TIME_ERROR /* bw compat */

	#ifdef __KERNEL__
	#include <linux/compiler.h>
	#include <linux/types.h>
	#include <linux/param.h>

	#include <asm/timex.h>

	/*
	* SHIFT_PLL is used as a dampening factor to define how much we
	* adjust the frequency correction for a given offset in PLL mode.
	* It also used in dampening the offset correction, to define how
	* much of the current value in time_offset we correct for each
	* second. Changing this value changes the stiffness of the ntp
	* adjustment code. A lower value makes it more flexible, reducing
	* NTP convergence time. A higher value makes it stiffer, increasing
	* convergence time, but making the clock more stable.
	*
	* In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
	* However this seems to increase convergence time much too long.
	*
	* https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
	*
	* In the above mailing list discussion, it seems the value of 4
	* was appropriate for other Unix systems with HZ=100, and that
	* SHIFT_PLL should be decreased as HZ increases. However, Linux's
	* clock steering implementation is HZ independent.
	*
	* Through experimentation, a SHIFT_PLL value of 2 was found to allow
	* for fast convergence (very similar to the NTPv3 code used prior to
	* v2.6.19), with good clock stability.
	*
	*
	* SHIFT_FLL is used as a dampening factor to define how much we
	* adjust the frequency correction for a given offset in FLL mode.
	* In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
	*
	* MAXTC establishes the maximum time constant of the PLL.
	*/
	#define SHIFT_PLL 2 /* PLL frequency factor (shift) */
	#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
	#define MAXTC 10 /* maximum time constant (shift) */

	/*
	* SHIFT_USEC defines the scaling (shift) of the time_freq and
	* time_tolerance variables, which represent the current frequency
	* offset and maximum frequency tolerance.
	*/
	#define SHIFT_USEC 16 /* frequency offset scale (shift) */
	#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
	#define PPM_SCALE_INV_SHIFT 19
	#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
	PPM_SCALE + 1)

	#define MAXPHASE 500000000L /* max phase error (ns) */
	#define MAXFREQ 500000 /* max frequency error (ns/s) */
	#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
	#define MINSEC 256 /* min interval between updates (s) */
	#define MAXSEC 2048 /* max interval between updates (s) */
	#define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */

	/*
	* kernel variables
	* Note: maximum error = NTP synch distance = dispersion + delay / 2;
	* estimated error = NTP dispersion.
	*/
	extern unsigned long tick_usec; /* USER_HZ period (usec) */
	extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
	extern int tickadj; /* amount of adjustment per tick */

	/*
	* phase-lock loop variables
	*/
	extern int time_status; /* clock synchronization status bits */
	extern long time_adjust; /* The amount of adjtime left */

	extern void ntp_init(void);
	extern void ntp_clear(void);

	/**
	* ntp_synced - Returns 1 if the NTP status is not UNSYNC
	*
	*/
	static inline int ntp_synced(void)
	{
	return !(time_status & STA_UNSYNC);
	}

	/* Required to safely shift negative values */
	#define shift_right(x, s) ({ \
	__typeof__(x) __x = (x); \
	__typeof__(s) __s = (s); \
	__x < 0 ? -(-__x >> __s) : __x >> __s; \
	})

	#define NTP_SCALE_SHIFT 32

	#define NTP_INTERVAL_FREQ (HZ)
	#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)

	/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
	extern u64 tick_length;

	extern void second_overflow(void);
	extern void update_ntp_one_tick(void);
	extern int do_adjtimex(struct timex *);

	/* Don't use! Compatibility define for existing users. */
	#define tickadj (500/HZ ? : 1)

	int read_current_timer(unsigned long *timer_val);

	/* The clock frequency of the i8253/i8254 PIT */
	#define PIT_TICK_RATE 1193182ul

	#endif /* KERNEL */

	#endif /* LINUX_TIMEX_H */