/*****************************************************************************
   *                                                                           *
   * 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/compiler.h>
  #include <linux/time.h>
  
  #include <asm/param.h>

  
  /*
   * 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_PLL	4	/* PLL frequency factor (shift) */
  #define SHIFT_FLL	2	/* FLL frequency factor (shift) */
  #define MAXTC		10	/* maximum time constant (shift) */

  
  /*

   * The SHIFT_UPDATE define establishes the decimal point of the
   * time_offset variable which represents the current offset with
   * respect to standard time.

   *
   * 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_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */

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

  #define SHIFT_NSEC 12		/* kernel frequency offset scale */

  
  #define MAXPHASE 512000L        /* max phase error (us) */
  #define MAXFREQ (512L << SHIFT_USEC)  /* max frequency error (ppm) */

  #define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */

  #define MINSEC 256		/* min interval between updates (s) */
  #define MAXSEC 2048		/* max interval between updates (s) */

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

   * 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__

  #include <asm/timex.h>

  /*
   * 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_maxerror;	/* maximum error */
  extern long time_esterror;	/* estimated error */
  
  extern long time_freq;		/* frequency offset (scaled ppm) */

  
  extern long time_adjust;	/* The amount of adjtime left */

  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 TICK_LENGTH_SHIFT	32

  #ifdef CONFIG_NO_HZ
  #define NTP_INTERVAL_FREQ  (2)
  #else
  #define NTP_INTERVAL_FREQ  (HZ)
  #endif
  #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)

  /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */

  extern u64 current_tick_length(void);

  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)

  #endif /* KERNEL */
  
  #endif /* LINUX_TIMEX_H */