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Diffstat (limited to 'include/linux/timex.h')
| -rw-r--r-- | include/linux/timex.h | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/include/linux/timex.h b/include/linux/timex.h new file mode 100644 index 000000000000..74fdd07d3792 --- /dev/null +++ b/include/linux/timex.h @@ -0,0 +1,320 @@ +/***************************************************************************** + * * + * 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/config.h> +#include <linux/compiler.h> +#include <linux/time.h> + +#include <asm/param.h> +#include <asm/timex.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_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) */ + +/* + * 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_freq; /* frequency offset (scaled ppm) */ +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 + +#define TIME_SOURCE_CPU 0 +#define TIME_SOURCE_MMIO64 1 +#define TIME_SOURCE_MMIO32 2 +#define TIME_SOURCE_FUNCTION 3 + +/* For proper operations time_interpolator clocks must run slightly slower + * than the standard clock since the interpolator may only correct by having + * time jump forward during a tick. A slower clock is usually a side effect + * of the integer divide of the nanoseconds in a second by the frequency. + * The accuracy of the division can be increased by specifying a shift. + * However, this may cause the clock not to be slow enough. + * The interpolator will self-tune the clock by slowing down if no + * resets occur or speeding up if the time jumps per analysis cycle + * become too high. + * + * Setting jitter compensates for a fluctuating timesource by comparing + * to the last value read from the timesource to insure that an earlier value + * is not returned by a later call. The price to pay + * for the compensation is that the timer routines are not as scalable anymore. + */ + +struct time_interpolator { + u16 source; /* time source flags */ + u8 shift; /* increases accuracy of multiply by shifting. */ + /* Note that bits may be lost if shift is set too high */ + u8 jitter; /* if set compensate for fluctuations */ + u32 nsec_per_cyc; /* set by register_time_interpolator() */ + void *addr; /* address of counter or function */ + u64 mask; /* mask the valid bits of the counter */ + unsigned long offset; /* nsec offset at last update of interpolator */ + u64 last_counter; /* counter value in units of the counter at last update */ + u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ + u64 frequency; /* frequency in counts/second */ + long drift; /* drift in parts-per-million (or -1) */ + unsigned long skips; /* skips forward */ + unsigned long ns_skipped; /* nanoseconds skipped */ + struct time_interpolator *next; +}; + +extern void register_time_interpolator(struct time_interpolator *); +extern void unregister_time_interpolator(struct time_interpolator *); +extern void time_interpolator_reset(void); +extern unsigned long time_interpolator_get_offset(void); + +#else /* !CONFIG_TIME_INTERPOLATION */ + +static inline void +time_interpolator_reset(void) +{ +} + +#endif /* !CONFIG_TIME_INTERPOLATION */ + +#endif /* KERNEL */ + +#endif /* LINUX_TIMEX_H */ |