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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

 *

 * 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

 */

#ifndef _LINUX_TIMEX_H

#define _LINUX_TIMEX_H

#include <linux/config.h>

#include <linux/compiler.h>

#include <asm/param.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.

 */

#if HZ >= 12 && HZ < 24

# define SHIFT_HZ       4

#elif HZ >= 24 && HZ < 48

# define SHIFT_HZ       5

#elif HZ >= 48 && HZ < 96

# define SHIFT_HZ       6

#elif HZ >= 96 && HZ < 192

# define SHIFT_HZ       7

#elif HZ >= 192 && HZ < 384

# define SHIFT_HZ       8

#elif HZ >= 384 && HZ < 768

# define SHIFT_HZ       9

#elif HZ >= 768 && HZ < 1536

# define SHIFT_HZ       10

#else

# error You lose.

#endif

/*

 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen

 * for a slightly underdamped convergence characteristic. SHIFT_KH

 * establishes the damping of the FLL and is chosen by wisdom and black

 * art.

 *

 * MAXTC establishes the maximum time constant of the PLL. With the

 * SHIFT_KG and SHIFT_KF values given and a time constant range from

 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,

 * respectively.

 */

#define SHIFT_KG 6              /* phase factor (shift) */

#define SHIFT_KF 16             /* PLL frequency factor (shift) */

#define SHIFT_KH 2              /* FLL frequency factor (shift) */

#define MAXTC 6                 /* maximum time constant (shift) */

/*

 * The SHIFT_SCALE define establishes the decimal point of the time_phase

 * variable which serves as 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 FINENSEC define represents 1 nsec in

 * scaled units.

 *

 * SHIFT_USEC defines the scaling (shift) of the time_freq and

 * time_tolerance variables, which represent the current frequency

 * offset and maximum frequency tolerance.

 *

 * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable.

 */

#define SHIFT_SCALE 22          /* phase scale (shift) */

#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */

#define SHIFT_USEC 16           /* frequency offset scale (shift) */

#define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */

#define MAXPHASE 512000L        /* max phase error (us) */

#define MAXFREQ (512L << SHIFT_USEC)  /* max frequency error (ppm) */

#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */

#define MINSEC 16L              /* min interval between updates (s) */

#define MAXSEC 1200L            /* max interval between updates (s) */

#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */

/*

 * The following defines are used only if a pulse-per-second (PPS)

 * signal is available and connected via a modem control lead, such as

 * produced by the optional ppsclock feature incorporated in the Sun

 * asynch driver. They establish the design parameters of the frequency-

 * lock loop used to discipline the CPU clock oscillator to the PPS

 * signal.

 *

 * PPS_AVG is the averaging factor for the frequency loop, as well as

 * the time and frequency dispersion.

 *

 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum

 * calibration intervals, respectively, in seconds as a power of two.

 *

 * PPS_VALID is the maximum interval before the PPS signal is considered

 * invalid and protocol updates used directly instead.

 *

 * MAXGLITCH is the maximum interval before a time offset of more than

 * MAXTIME is believed.

 */

#define PPS_AVG 2               /* pps averaging constant (shift) */

#define PPS_SHIFT 2             /* min interval duration (s) (shift) */

#define PPS_SHIFTMAX 8          /* max interval duration (s) (shift) */

#define PPS_VALID 120           /* pps signal watchdog max (s) */

#define MAXGLITCH 30            /* pps signal glitch max (s) */

/*

 * Pick up the architecture specific timex specifications

 */

#include <asm/timex.h>

/* LATCH is used in the interval timer and ftape setup. */

#define LATCH  ((CLOCK_TICK_RATE + HZ/2) / HZ)  /* For divider */

/* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can

 * improve accuracy by shifting LSH bits, hence calculating:

 *     (NOM << LSH) / DEN

 * This however means trouble for large NOM, because (NOM << LSH) may no

 * longer fit in 32 bits. The following way of calculating this gives us

 * some slack, under the following conditions:

 *   - (NOM / DEN) fits in (32 - LSH) bits.

 *   - (NOM % DEN) fits in (32 - LSH) bits.

 */

#define SH_DIV(NOM,DEN,LSH) (   ((NOM / DEN) << LSH)                    \

                             + (((NOM % DEN) << LSH) + DEN / 2) / DEN)

/* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */

#define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8))

/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */

#define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8))

/* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */

#define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)

/* TICK_USEC_TO_NSEC is the time between ticks in nsec assuming real ACTHZ and  */

/* a value TUSEC for TICK_USEC (can be set bij adjtimex)                */

#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV (TUSEC * USER_HZ * 1000, ACTHZ, 8))

#include <linux/time.h>

/*

 * 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  :32; 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_TICK                0x4000  /* tick value */

#define ADJ_OFFSET_SINGLESHOT   0x8001  /* old-fashioned adjtime */

/* xntp 3.4 compatibility names */

#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_CLKB        ADJ_TICK

#define MOD_CLKA        ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */

/*

 * 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_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \

    STA_PPSERROR | STA_CLOCKERR) /* read-only bits */

/*

 * 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__

/*

 * 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_state;          /* clock status */

extern int time_status;         /* clock synchronization status bits */

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 */

extern long time_next_adjust;   /* Value for time_adjust at next tick */

/* interface variables pps->timer interrupt */

extern long pps_offset;         /* pps time offset (us) */

extern long pps_jitter;         /* time dispersion (jitter) (us) */

extern long pps_freq;           /* frequency offset (scaled ppm) */

extern long pps_stabil;         /* frequency dispersion (scaled ppm) */

extern long pps_valid;          /* pps signal watchdog counter */

/* interface variables pps->adjtimex */

extern int pps_shift;           /* interval duration (s) (shift) */

extern long pps_jitcnt;         /* jitter limit exceeded */

extern long pps_calcnt;         /* calibration intervals */

extern long pps_errcnt;         /* calibration errors */

extern long pps_stbcnt;         /* stability limit exceeded */

#ifdef CONFIG_TIME_INTERPOLATION

struct time_interpolator {

        /* cache-hot stuff first: */

        unsigned long (*get_offset) (void);

        void (*update) (long);

        void (*reset) (void);

        /* cache-cold stuff follows here: */

        struct time_interpolator *next;

        unsigned long frequency;        /* frequency in counts/second */

        long drift;                     /* drift in parts-per-million (or -1) */

};

extern volatile unsigned long last_nsec_offset;

#ifndef __HAVE_ARCH_CMPXCHG

extern spin_lock_t last_nsec_offset_lock;

#endif

extern struct time_interpolator *time_interpolator;

extern void register_time_interpolator(struct time_interpolator *);

extern void unregister_time_interpolator(struct time_interpolator *);

/* Called with xtime WRITE-lock acquired.  */

static inline void

time_interpolator_update(long delta_nsec)

{

        struct time_interpolator *ti = time_interpolator;

        if (last_nsec_offset > 0) {

#ifdef __HAVE_ARCH_CMPXCHG

                unsigned long new, old;

                do {

                        old = last_nsec_offset;

                        if (old > delta_nsec)

                                new = old - delta_nsec;

                        else

                                new = 0;

                } while (cmpxchg(&last_nsec_offset, old, new) != old);

#else

                /*

                 * This really hurts, because it serializes gettimeofday(), but without an

                 * atomic single-word compare-and-exchange, there isn't all that much else

                 * we can do.

                 */

                spin_lock(&last_nsec_offset_lock);

                {

                        last_nsec_offset -= min(last_nsec_offset, delta_nsec);

                }

                spin_unlock(&last_nsec_offset_lock);

#endif

        }

        if (ti)

                (*ti->update)(delta_nsec);

}

/* Called with xtime WRITE-lock acquired.  */

static inline void

time_interpolator_reset(void)

{

        struct time_interpolator *ti = time_interpolator;

        last_nsec_offset = 0;

        if (ti)

                (*ti->reset)();

}

/* Called with xtime READ-lock acquired.  */

static inline unsigned long

time_interpolator_get_offset(void)

{

        struct time_interpolator *ti = time_interpolator;

        if (ti)

                return (*ti->get_offset)();

        return last_nsec_offset;

}

#else /* !CONFIG_TIME_INTERPOLATION */

static inline void

time_interpolator_update(long delta_nsec)

{

}

static inline void

time_interpolator_reset(void)

{

}

static inline unsigned long

time_interpolator_get_offset(void)

{

        return 0;

}

#endif /* !CONFIG_TIME_INTERPOLATION */

#endif /* KERNEL */

#endif /* LINUX_TIMEX_H */