diff options
Diffstat (limited to 'kernel/sys/timex.h')
| -rw-r--r-- | kernel/sys/timex.h | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/kernel/sys/timex.h b/kernel/sys/timex.h new file mode 100644 index 0000000..d42ec08 --- /dev/null +++ b/kernel/sys/timex.h @@ -0,0 +1,309 @@ +/****************************************************************************** + * * + * Copyright (c) David L. Mills 1993, 1994 * + * * + * 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 + * + * 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 + */ +/* + * This header file defines the Network Time Protocol (NTP) interfaces + * for user and daemon application programs. These are implemented using + * private syscalls and data structures and require specific kernel + * support. + * + * NAME + * ntp_gettime - NTP user application interface + * + * SYNOPSIS + * #include <sys/timex.h> + * + * int syscall(SYS_ntp_gettime, tptr) + * + * int SYS_ntp_gettime defined in syscall.h header file + * struct ntptimeval *tptr pointer to ntptimeval structure + * + * NAME + * ntp_adjtime - NTP daemon application interface + * + * SYNOPSIS + * #include <sys/timex.h> + * + * int syscall(SYS_ntp_adjtime, mode, tptr) + * + * int SYS_ntp_adjtime defined in syscall.h header file + * struct timex *tptr pointer to timex structure + * + */ +#ifndef _SYS_TIMEX_H_ +#define _SYS_TIMEX_H_ 1 + +#ifndef MSDOS /* Microsoft specific */ +#include <sys/syscall.h> +#endif /* MSDOS */ + +/* + * The following defines establish the engineering parameters of the + * phase-lock loop (PLL) model used in the kernel implementation. These + * parameters have been carefully chosen by analysis for good stability + * and wide dynamic range. + * + * The hz variable is defined in the kernel build environment. It + * 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. SHIFT_HZ expresses the same value as the nearest power of two + * in order to avoid hardware multiply operations. + * + * 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_HZ 7 /* log2(hz) */ +#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 following defines establish the scaling of the various variables + * used by the PLL. They are chosen to allow the greatest precision + * possible without overflow of a 32-bit word. + * + * SHIFT_SCALE defines the scaling (shift) of the time_phase variable, + * which serves as a an extension to the low-order bits of the system + * clock variable time.tv_usec. + * + * SHIFT_UPDATE defines the scaling (shift) of the time_offset variable, + * which represents the current time 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. + * + * FINEUSEC is 1 us 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 FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */ + +/* + * The following defines establish the performance envelope of the PLL. + * They insure it operates within predefined limits, in order to satisfy + * correctness assertions. An excursion which exceeds these bounds is + * clamped to the bound and operation proceeds accordingly. In practice, + * this can occur only if something has failed or is operating out of + * tolerance, but otherwise the PLL continues to operate in a stable + * mode. + * + * MAXPHASE must be set greater than or equal to CLOCK.MAX (128 ms), as + * defined in the NTP specification. CLOCK.MAX establishes the maximum + * time offset allowed before the system time is reset, rather than + * incrementally adjusted. Here, the maximum offset is clamped to + * MAXPHASE only in order to prevent overflow errors due to defective + * protocol implementations. + * + * MAXFREQ is the maximum frequency tolerance of the CPU clock + * oscillator plus the maximum slew rate allowed by the protocol. It + * should be set to at least the frequency tolerance of the oscillator + * plus 100 ppm for vernier frequency adjustments. If the kernel + * PPS discipline code is configured (PPS_SYNC), the oscillator time and + * frequency are disciplined to an external source, presumably with + * negligible time and frequency error relative to UTC, and MAXFREQ can + * be reduced. + * + * MAXTIME is the maximum jitter tolerance of the PPS signal if the + * kernel PPS discipline code is configured (PPS_SYNC). + * + * MINSEC and MAXSEC define the lower and upper bounds on the interval + * between protocol updates. + */ +#define MAXPHASE 512000L /* max phase error (us) */ +#ifdef PPS_SYNC +#define MAXFREQ (512L << SHIFT_USEC) /* max freq error (100 ppm) */ +#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */ +#else +#define MAXFREQ (512L << SHIFT_USEC) /* max freq error (200 ppm) */ +#endif /* PPS_SYNC */ +#define MINSEC 16L /* min interval between updates (s) */ +#define MAXSEC 1200L /* max interval between updates (s) */ + +#ifdef PPS_SYNC +/* + * 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) */ +#endif /* PPS_SYNC */ + +/* + * The following defines and structures define the user interface for + * the ntp_gettime() and ntp_adjtime() system calls. + * + * Control mode codes (timex.modes) + */ +#define MOD_OFFSET 0x0001 /* set time offset */ +#define MOD_FREQUENCY 0x0002 /* set frequency offset */ +#define MOD_MAXERROR 0x0004 /* set maximum time error */ +#define MOD_ESTERROR 0x0008 /* set estimated time error */ +#define MOD_STATUS 0x0010 /* set clock status bits */ +#define MOD_TIMECONST 0x0020 /* set pll time constant */ +#define MOD_CANSCALE 0x0040 /* kernel can scale offset field */ +#define MOD_DOSCALE 0x0080 /* userland wants to scale offset field */ + +/* + * 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 /* no leap second warning */ +#define TIME_INS 1 /* insert leap second warning */ +#define TIME_DEL 2 /* delete leap second warning */ +#define TIME_OOP 3 /* leap second in progress */ +#define TIME_WAIT 4 /* leap second has occurred */ +#define TIME_ERROR 5 /* clock not synchronized */ + +/* + * NTP user interface (ntp_gettime()) - used to read kernel clock values + * + * Note: maximum error = NTP synch distance = dispersion + delay / 2; + * estimated error = NTP dispersion. + */ +struct ntptimeval { + struct timeval time; /* current time (ro) */ + long maxerror; /* maximum error (us) (ro) */ + long esterror; /* estimated error (us) (ro) */ +}; + +/* + * NTP daemon interface - (ntp_adjtime()) used to discipline CPU clock + * oscillator + */ +struct timex { + unsigned int modes; /* clock mode bits (wo) */ + long offset; /* time offset (us) (rw) */ + long freq; /* frequency offset (scaled ppm) (rw) */ + long maxerror; /* maximum error (us) (rw) */ + long esterror; /* estimated error (us) (rw) */ + int status; /* clock status bits (rw) */ + long constant; /* pll time constant (rw) */ + long precision; /* clock precision (us) (ro) */ + long tolerance; /* clock frequency tolerance (scaled + * ppm) (ro) */ + /* + * The following read-only structure members are implemented + * only if the PPS signal discipline is configured in the + * kernel. + */ + 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) */ + +}; +#ifdef __FreeBSD__ + +/* + * sysctl identifiers underneath kern.ntp_pll + */ +#define NTP_PLL_GETTIME 1 /* used by ntp_gettime() */ +#define NTP_PLL_MAXID 2 /* number of valid ids */ + +#define NTP_PLL_NAMES { \ + { 0, 0 }, \ + { "gettime", CTLTYPE_STRUCT }, \ + } + +#ifndef KERNEL +#include <sys/cdefs.h> + +__BEGIN_DECLS +extern int ntp_gettime __P((struct ntptimeval *)); +extern int ntp_adjtime __P((struct timex *)); +__END_DECLS + +#endif /* not KERNEL */ + +#endif /* __FreeBSD__ */ +#endif /* _SYS_TIMEX_H_ */ |