[net-next-2.6.git] / include / 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) */

/*
 * phase-lock loop variables
 */
extern int time_status;		/* clock synchronization status bits */

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 *);

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 */
Commit	Line	Data
1da177e4 LT	1	/*****************************************************************************
	2	* *
	3	* Copyright (c) David L. Mills 1993 *
	4	* *
	5	* Permission to use, copy, modify, and distribute this software and its *
	6	* documentation for any purpose and without fee is hereby granted, provided *
	7	* that the above copyright notice appears in all copies and that both the *
	8	* copyright notice and this permission notice appear in supporting *
	9	* documentation, and that the name University of Delaware not be used in *
	10	* advertising or publicity pertaining to distribution of the software *
	11	* without specific, written prior permission. The University of Delaware *
	12	* makes no representations about the suitability this software for any *
	13	* purpose. It is provided "as is" without express or implied warranty. *
	14	* *
	15	*****************************************************************************/
	16
	17	/*
	18	* Modification history timex.h
	19	*
	20	* 29 Dec 97 Russell King
	21	* Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h
	22	* for ARM machines
	23	*
	24	* 9 Jan 97 Adrian Sun
	25	* Shifted LATCH define to allow access to alpha machines.
	26	*
	27	* 26 Sep 94 David L. Mills
	28	* Added defines for hybrid phase/frequency-lock loop.
	29	*
	30	* 19 Mar 94 David L. Mills
	31	* Moved defines from kernel routines to header file and added new
	32	* defines for PPS phase-lock loop.
	33	*
	34	* 20 Feb 94 David L. Mills
	35	* Revised status codes and structures for external clock and PPS
	36	* signal discipline.
	37	*
	38	* 28 Nov 93 David L. Mills
	39	* Adjusted parameters to improve stability and increase poll
	40	* interval.
	41	*
	42	* 17 Sep 93 David L. Mills
	43	* Created file $NTP/include/sys/timex.h
	44	* 07 Oct 93 Torsten Duwe
	45	* Derived linux/timex.h
	46	* 1995-08-13 Torsten Duwe
	47	* kernel PLL updated to 1994-12-13 specs (rfc-1589)
	48	* 1997-08-30 Ulrich Windl
	49	* Added new constant NTP_PHASE_LIMIT
	50	* 2004-08-12 Christoph Lameter
	51	* Reworked time interpolation logic
	52	*/
	53	#ifndef _LINUX_TIMEX_H
	54	#define _LINUX_TIMEX_H
	55
1da177e4 LT	56	#include <linux/time.h>
1da177e4 LT	57
eea83d89 RZ	58	#define NTP_API 4 /* NTP API version */
eea83d89 RZ	59
1da177e4 LT	60	/*
	61	* syscall interface - used (mainly by NTP daemon)
	62	* to discipline kernel clock oscillator
	63	*/
	64	struct timex {
	65	unsigned int modes; /* mode selector */
	66	long offset; /* time offset (usec) */
	67	long freq; /* frequency offset (scaled ppm) */
	68	long maxerror; /* maximum error (usec) */
	69	long esterror; /* estimated error (usec) */
	70	int status; /* clock command/status */
	71	long constant; /* pll time constant */
	72	long precision; /* clock precision (usec) (read only) */
	73	long tolerance; /* clock frequency tolerance (ppm)
	74	* (read only)
	75	*/
	76	struct timeval time; /* (read only) */
	77	long tick; /* (modified) usecs between clock ticks */
	78
	79	long ppsfreq; /* pps frequency (scaled ppm) (ro) */
	80	long jitter; /* pps jitter (us) (ro) */
	81	int shift; /* interval duration (s) (shift) (ro) */
	82	long stabil; /* pps stability (scaled ppm) (ro) */
	83	long jitcnt; /* jitter limit exceeded (ro) */
	84	long calcnt; /* calibration intervals (ro) */
	85	long errcnt; /* calibration errors (ro) */
	86	long stbcnt; /* stability limit exceeded (ro) */
	87
153b5d05 RZ	88	int tai; /* TAI offset (ro) */
153b5d05 RZ	89
1da177e4 LT	90	int :32; int :32; int :32; int :32;
1da177e4 LT	91	int :32; int :32; int :32; int :32;
153b5d05	92	int :32; int :32; int :32;
1da177e4 LT	93	};
	94
	95	/*
	96	* Mode codes (timex.mode)
	97	*/
	98	#define ADJ_OFFSET 0x0001 /* time offset */
	99	#define ADJ_FREQUENCY 0x0002 /* frequency offset */
	100	#define ADJ_MAXERROR 0x0004 /* maximum time error */
	101	#define ADJ_ESTERROR 0x0008 /* estimated time error */
	102	#define ADJ_STATUS 0x0010 /* clock status */
	103	#define ADJ_TIMECONST 0x0020 /* pll time constant */
153b5d05	104	#define ADJ_TAI 0x0080 /* set TAI offset */
eea83d89 RZ	105	#define ADJ_MICRO 0x1000 /* select microsecond resolution */
eea83d89 RZ	106	#define ADJ_NANO 0x2000 /* select nanosecond resolution */
1da177e4	107	#define ADJ_TICK 0x4000 /* tick value */
916c7a85 RZ	108
	109	#ifdef __KERNEL__
	110	#define ADJ_ADJTIME 0x8000 /* switch between adjtime/adjtimex modes */
	111	#define ADJ_OFFSET_SINGLESHOT 0x0001 /* old-fashioned adjtime */
	112	#define ADJ_OFFSET_READONLY 0x2000 /* read-only adjtime */
	113	#else
1da177e4	114	#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
916c7a85 RZ	115	#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
916c7a85 RZ	116	#endif
1da177e4	117
c95b4502	118	/* NTP userland likes the MOD_ prefix better */
1da177e4 LT	119	#define MOD_OFFSET ADJ_OFFSET
	120	#define MOD_FREQUENCY ADJ_FREQUENCY
	121	#define MOD_MAXERROR ADJ_MAXERROR
	122	#define MOD_ESTERROR ADJ_ESTERROR
	123	#define MOD_STATUS ADJ_STATUS
	124	#define MOD_TIMECONST ADJ_TIMECONST
c95b4502 JS	125	#define MOD_TAI ADJ_TAI
	126	#define MOD_MICRO ADJ_MICRO
	127	#define MOD_NANO ADJ_NANO
1da177e4 LT	128
	129
	130	/*
	131	* Status codes (timex.status)
	132	*/
	133	#define STA_PLL 0x0001 /* enable PLL updates (rw) */
	134	#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */
	135	#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */
	136	#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */
	137
	138	#define STA_INS 0x0010 /* insert leap (rw) */
	139	#define STA_DEL 0x0020 /* delete leap (rw) */
	140	#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */
	141	#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */
	142
	143	#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */
	144	#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */
	145	#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */
	146	#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
	147
	148	#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
eea83d89 RZ	149	#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
	150	#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
	151	#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */
1da177e4	152
eea83d89	153	/* read-only bits */
1da177e4	154	#define STA_RONLY (STA_PPSSIGNAL \| STA_PPSJITTER \| STA_PPSWANDER \| \
eea83d89	155	STA_PPSERROR \| STA_CLOCKERR \| STA_NANO \| STA_MODE \| STA_CLK)
1da177e4 LT	156
	157	/*
	158	* Clock states (time_state)
	159	*/
	160	#define TIME_OK 0 /* clock synchronized, no leap second */
	161	#define TIME_INS 1 /* insert leap second */
	162	#define TIME_DEL 2 /* delete leap second */
	163	#define TIME_OOP 3 /* leap second in progress */
	164	#define TIME_WAIT 4 /* leap second has occurred */
	165	#define TIME_ERROR 5 /* clock not synchronized */
	166	#define TIME_BAD TIME_ERROR /* bw compat */
	167
	168	#ifdef __KERNEL__
c29541b2 MF	169	#include <linux/compiler.h>
	170	#include <linux/types.h>
	171	#include <linux/param.h>
	172
ee6baf88 DW	173	#include <asm/timex.h>
ee6baf88 DW	174
c29541b2	175	/*
22cfbbfd JS	176	* SHIFT_PLL is used as a dampening factor to define how much we
	177	* adjust the frequency correction for a given offset in PLL mode.
	178	* It also used in dampening the offset correction, to define how
	179	* much of the current value in time_offset we correct for each
	180	* second. Changing this value changes the stiffness of the ntp
	181	* adjustment code. A lower value makes it more flexible, reducing
	182	* NTP convergence time. A higher value makes it stiffer, increasing
	183	* convergence time, but making the clock more stable.
c29541b2	184	*
e13cf6e0	185	* In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
22cfbbfd JS	186	* However this seems to increase convergence time much too long.
	187	*
	188	* https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
	189	*
	190	* In the above mailing list discussion, it seems the value of 4
	191	* was appropriate for other Unix systems with HZ=100, and that
	192	* SHIFT_PLL should be decreased as HZ increases. However, Linux's
	193	* clock steering implementation is HZ independent.
	194	*
	195	* Through experimentation, a SHIFT_PLL value of 2 was found to allow
	196	* for fast convergence (very similar to the NTPv3 code used prior to
	197	* v2.6.19), with good clock stability.
	198	*
	199	*
	200	* SHIFT_FLL is used as a dampening factor to define how much we
	201	* adjust the frequency correction for a given offset in FLL mode.
e13cf6e0	202	* In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
22cfbbfd JS	203	*
22cfbbfd JS	204	* MAXTC establishes the maximum time constant of the PLL.
c29541b2	205	*/
22cfbbfd	206	#define SHIFT_PLL 2 /* PLL frequency factor (shift) */
c29541b2 MF	207	#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
	208	#define MAXTC 10 /* maximum time constant (shift) */
	209
	210	/*
	211	* SHIFT_USEC defines the scaling (shift) of the time_freq and
	212	* time_tolerance variables, which represent the current frequency
	213	* offset and maximum frequency tolerance.
	214	*/
	215	#define SHIFT_USEC 16 /* frequency offset scale (shift) */
2b9d1496	216	#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
c29541b2	217	#define PPM_SCALE_INV_SHIFT 19
22cfbbfd	218	#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
c29541b2 MF	219	PPM_SCALE + 1)
c29541b2 MF	220
22cfbbfd	221	#define MAXPHASE 500000000L /* max phase error (ns) */
c29541b2 MF	222	#define MAXFREQ 500000 /* max frequency error (ns/s) */
	223	#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
	224	#define MINSEC 256 /* min interval between updates (s) */
	225	#define MAXSEC 2048 /* max interval between updates (s) */
	226	#define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */
	227
1da177e4 LT	228	/*
	229	* kernel variables
	230	* Note: maximum error = NTP synch distance = dispersion + delay / 2;
	231	* estimated error = NTP dispersion.
	232	*/
	233	extern unsigned long tick_usec; /* USER_HZ period (usec) */
	234	extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
1da177e4 LT	235
	236	/*
	237	* phase-lock loop variables
	238	*/
1da177e4	239	extern int time_status; /* clock synchronization status bits */
1da177e4	240
7dffa3c6	241	extern void ntp_init(void);
b0ee7556	242	extern void ntp_clear(void);
b149ee22 JS	243
	244	/**
	245	* ntp_synced - Returns 1 if the NTP status is not UNSYNC
	246	*
	247	*/
	248	static inline int ntp_synced(void)
	249	{
	250	return !(time_status & STA_UNSYNC);
	251	}
	252
1bb34a41 JS	253	/* Required to safely shift negative values */
	254	#define shift_right(x, s) ({ \
	255	__typeof__(x) __x = (x); \
	256	__typeof__(s) __s = (s); \
	257	__x < 0 ? -(-__x >> __s) : __x >> __s; \
	258	})
	259
7fc5c784	260	#define NTP_SCALE_SHIFT 32
19923c19	261
f4304ab2	262	#define NTP_INTERVAL_FREQ (HZ)
10a398d0	263	#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
f4304ab2	264
8383c423 RZ	265	/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
8383c423 RZ	266	extern u64 tick_length;
726c14bf	267
4c7ee8de JS	268	extern void second_overflow(void);
4c7ee8de JS	269	extern void update_ntp_one_tick(void);
3158e941 SR	270	extern int do_adjtimex(struct timex *);
3158e941 SR	271
941e492b AM	272	int read_current_timer(unsigned long *timer_val);
941e492b AM	273
08604bd9 AB	274	/* The clock frequency of the i8253/i8254 PIT */
	275	#define PIT_TICK_RATE 1193182ul
	276
1da177e4 LT	277	#endif /* KERNEL */
	278
	279	#endif /* LINUX_TIMEX_H */