1 /* $NetBSD: timex.h,v 1.5 2020/05/25 20:47:20 christos Exp $ */ 2 3 /****************************************************************************** 4 * * 5 * Copyright (c) David L. Mills 1993, 1994 * 6 * * 7 * Permission to use, copy, modify, and distribute this software and its * 8 * documentation for any purpose and without fee is hereby granted, provided * 9 * that the above copyright notice appears in all copies and that both the * 10 * copyright notice and this permission notice appear in supporting * 11 * documentation, and that the name University of Delaware not be used in * 12 * advertising or publicity pertaining to distribution of the software * 13 * without specific, written prior permission. The University of Delaware * 14 * makes no representations about the suitability this software for any * 15 * purpose. It is provided "as is" without express or implied warranty. * 16 * * 17 ******************************************************************************/ 18 19 /* 20 * Modification history timex.h 21 * 22 * 26 Sep 94 David L. Mills 23 * Added defines for hybrid phase/frequency-lock loop. 24 * 25 * 19 Mar 94 David L. Mills 26 * Moved defines from kernel routines to header file and added new 27 * defines for PPS phase-lock loop. 28 * 29 * 20 Feb 94 David L. Mills 30 * Revised status codes and structures for external clock and PPS 31 * signal discipline. 32 * 33 * 28 Nov 93 David L. Mills 34 * Adjusted parameters to improve stability and increase poll 35 * interval. 36 * 37 * 17 Sep 93 David L. Mills 38 * Created file 39 */ 40 /* 41 * This header file defines the Network Time Protocol (NTP) interfaces 42 * for user and daemon application programs. These are implemented using 43 * private syscalls and data structures and require specific kernel 44 * support. 45 * 46 * NAME 47 * ntp_gettime - NTP user application interface 48 * 49 * SYNOPSIS 50 * #include <sys/timex.h> 51 * 52 * int syscall(SYS_ntp_gettime, tptr) 53 * 54 * int SYS_ntp_gettime defined in syscall.h header file 55 * struct ntptimeval *tptr pointer to ntptimeval structure 56 * 57 * NAME 58 * ntp_adjtime - NTP daemon application interface 59 * 60 * SYNOPSIS 61 * #include <sys/timex.h> 62 * 63 * int syscall(SYS_ntp_adjtime, mode, tptr) 64 * 65 * int SYS_ntp_adjtime defined in syscall.h header file 66 * struct timex *tptr pointer to timex structure 67 * 68 */ 69 #ifndef _SYS_TIMEX_H_ 70 #define _SYS_TIMEX_H_ 1 71 72 #ifndef MSDOS /* Microsoft specific */ 73 #include <sys/syscall.h> 74 #endif /* MSDOS */ 75 76 /* 77 * The following defines establish the engineering parameters of the 78 * phase-lock loop (PLL) model used in the kernel implementation. These 79 * parameters have been carefully chosen by analysis for good stability 80 * and wide dynamic range. 81 * 82 * The hz variable is defined in the kernel build environment. It 83 * establishes the timer interrupt frequency, 100 Hz for the SunOS 84 * kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the OSF/1 85 * kernel. SHIFT_HZ expresses the same value as the nearest power of two 86 * in order to avoid hardware multiply operations. 87 * 88 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen 89 * for a slightly underdamped convergence characteristic. SHIFT_KH 90 * establishes the damping of the FLL and is chosen by wisdom and black 91 * art. 92 * 93 * MAXTC establishes the maximum time constant of the PLL. With the 94 * SHIFT_KG and SHIFT_KF values given and a time constant range from 95 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, 96 * respectively. 97 */ 98 #define SHIFT_HZ 7 /* log2(hz) */ 99 #define SHIFT_KG 6 /* phase factor (shift) */ 100 #define SHIFT_KF 16 /* PLL frequency factor (shift) */ 101 #define SHIFT_KH 2 /* FLL frequency factor (shift) */ 102 #define MAXTC 6 /* maximum time constant (shift) */ 103 104 /* 105 * The following defines establish the scaling of the various variables 106 * used by the PLL. They are chosen to allow the greatest precision 107 * possible without overflow of a 32-bit word. 108 * 109 * SHIFT_SCALE defines the scaling (shift) of the time_phase variable, 110 * which serves as a an extension to the low-order bits of the system 111 * clock variable time.tv_usec. 112 * 113 * SHIFT_UPDATE defines the scaling (shift) of the time_offset variable, 114 * which represents the current time offset with respect to standard 115 * time. 116 * 117 * SHIFT_USEC defines the scaling (shift) of the time_freq and 118 * time_tolerance variables, which represent the current frequency 119 * offset and maximum frequency tolerance. 120 * 121 * FINEUSEC is 1 us in SHIFT_UPDATE units of the time_phase variable. 122 */ 123 #define SHIFT_SCALE 22 /* phase scale (shift) */ 124 #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */ 125 #define SHIFT_USEC 16 /* frequency offset scale (shift) */ 126 #define FINEUSEC (1L << SHIFT_SCALE) /* 1 us in phase units */ 127 128 /* 129 * The following defines establish the performance envelope of the PLL. 130 * They insure it operates within predefined limits, in order to satisfy 131 * correctness assertions. An excursion which exceeds these bounds is 132 * clamped to the bound and operation proceeds accordingly. In practice, 133 * this can occur only if something has failed or is operating out of 134 * tolerance, but otherwise the PLL continues to operate in a stable 135 * mode. 136 * 137 * MAXPHASE must be set greater than or equal to CLOCK.MAX (128 ms), as 138 * defined in the NTP specification. CLOCK.MAX establishes the maximum 139 * time offset allowed before the system time is reset, rather than 140 * incrementally adjusted. Here, the maximum offset is clamped to 141 * MAXPHASE only in order to prevent overflow errors due to defective 142 * protocol implementations. 143 * 144 * MAXFREQ is the maximum frequency tolerance of the CPU clock 145 * oscillator plus the maximum slew rate allowed by the protocol. It 146 * should be set to at least the frequency tolerance of the oscillator 147 * plus 100 ppm for vernier frequency adjustments. If the kernel 148 * PPS discipline code is configured (PPS_SYNC), the oscillator time and 149 * frequency are disciplined to an external source, presumably with 150 * negligible time and frequency error relative to UTC, and MAXFREQ can 151 * be reduced. 152 * 153 * MAXTIME is the maximum jitter tolerance of the PPS signal if the 154 * kernel PPS discipline code is configured (PPS_SYNC). 155 * 156 * MINSEC and MAXSEC define the lower and upper bounds on the interval 157 * between protocol updates. 158 */ 159 #define MAXPHASE 512000L /* max phase error (us) */ 160 #ifdef PPS_SYNC 161 #define MAXFREQ (512L << SHIFT_USEC) /* max freq error (100 ppm) */ 162 #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */ 163 #else 164 #define MAXFREQ (512L << SHIFT_USEC) /* max freq error (200 ppm) */ 165 #endif /* PPS_SYNC */ 166 #define MINSEC 16L /* min interval between updates (s) */ 167 #define MAXSEC 1200L /* max interval between updates (s) */ 168 169 #ifdef PPS_SYNC 170 /* 171 * The following defines are used only if a pulse-per-second (PPS) 172 * signal is available and connected via a modem control lead, such as 173 * produced by the optional ppsclock feature incorporated in the Sun 174 * asynch driver. They establish the design parameters of the frequency- 175 * lock loop used to discipline the CPU clock oscillator to the PPS 176 * signal. 177 * 178 * PPS_AVG is the averaging factor for the frequency loop, as well as 179 * the time and frequency dispersion. 180 * 181 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum 182 * calibration intervals, respectively, in seconds as a power of two. 183 * 184 * PPS_VALID is the maximum interval before the PPS signal is considered 185 * invalid and protocol updates used directly instead. 186 * 187 * MAXGLITCH is the maximum interval before a time offset of more than 188 * MAXTIME is believed. 189 */ 190 #define PPS_AVG 2 /* pps averaging constant (shift) */ 191 #define PPS_SHIFT 2 /* min interval duration (s) (shift) */ 192 #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */ 193 #define PPS_VALID 120 /* pps signal watchdog max (s) */ 194 #define MAXGLITCH 30 /* pps signal glitch max (s) */ 195 #endif /* PPS_SYNC */ 196 197 /* 198 * The following defines and structures define the user interface for 199 * the ntp_gettime() and ntp_adjtime() system calls. 200 * 201 * Control mode codes (timex.modes) 202 */ 203 #define MOD_OFFSET 0x0001 /* set time offset */ 204 #define MOD_FREQUENCY 0x0002 /* set frequency offset */ 205 #define MOD_MAXERROR 0x0004 /* set maximum time error */ 206 #define MOD_ESTERROR 0x0008 /* set estimated time error */ 207 #define MOD_STATUS 0x0010 /* set clock status bits */ 208 #define MOD_TIMECONST 0x0020 /* set pll time constant */ 209 #define MOD_CANSCALE 0x0040 /* kernel can scale offset field */ 210 #define MOD_DOSCALE 0x0080 /* userland wants to scale offset field */ 211 212 /* 213 * Status codes (timex.status) 214 */ 215 #define STA_PLL 0x0001 /* enable PLL updates (rw) */ 216 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ 217 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ 218 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ 219 220 #define STA_INS 0x0010 /* insert leap (rw) */ 221 #define STA_DEL 0x0020 /* delete leap (rw) */ 222 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ 223 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ 224 225 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ 226 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ 227 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ 228 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ 229 230 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ 231 232 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ 233 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ 234 235 /* 236 * Clock states (time_state) 237 */ 238 #define TIME_OK 0 /* no leap second warning */ 239 #define TIME_INS 1 /* insert leap second warning */ 240 #define TIME_DEL 2 /* delete leap second warning */ 241 #define TIME_OOP 3 /* leap second in progress */ 242 #define TIME_WAIT 4 /* leap second has occurred */ 243 #define TIME_ERROR 5 /* clock not synchronized */ 244 245 /* 246 * NTP user interface (ntp_gettime()) - used to read kernel clock values 247 * 248 * Note: maximum error = NTP synch distance = dispersion + delay / 2; 249 * estimated error = NTP dispersion. 250 */ 251 struct ntptimeval { 252 struct timeval time; /* current time (ro) */ 253 long maxerror; /* maximum error (us) (ro) */ 254 long esterror; /* estimated error (us) (ro) */ 255 }; 256 257 /* 258 * NTP daemon interface - (ntp_adjtime()) used to discipline CPU clock 259 * oscillator 260 */ 261 struct timex { 262 unsigned int modes; /* clock mode bits (wo) */ 263 long offset; /* time offset (us) (rw) */ 264 long freq; /* frequency offset (scaled ppm) (rw) */ 265 long maxerror; /* maximum error (us) (rw) */ 266 long esterror; /* estimated error (us) (rw) */ 267 int status; /* clock status bits (rw) */ 268 long constant; /* pll time constant (rw) */ 269 long precision; /* clock precision (us) (ro) */ 270 long tolerance; /* clock frequency tolerance (scaled 271 * ppm) (ro) */ 272 /* 273 * The following read-only structure members are implemented 274 * only if the PPS signal discipline is configured in the 275 * kernel. 276 */ 277 long ppsfreq; /* pps frequency (scaled ppm) (ro) */ 278 long jitter; /* pps jitter (us) (ro) */ 279 int shift; /* interval duration (s) (shift) (ro) */ 280 long stabil; /* pps stability (scaled ppm) (ro) */ 281 long jitcnt; /* jitter limit exceeded (ro) */ 282 long calcnt; /* calibration intervals (ro) */ 283 long errcnt; /* calibration errors (ro) */ 284 long stbcnt; /* stability limit exceeded (ro) */ 285 286 }; 287 #ifdef __FreeBSD__ 288 289 /* 290 * sysctl identifiers underneath kern.ntp_pll 291 */ 292 #define NTP_PLL_GETTIME 1 /* used by ntp_gettime() */ 293 #define NTP_PLL_MAXID 2 /* number of valid ids */ 294 295 #define NTP_PLL_NAMES { \ 296 { 0, 0 }, \ 297 { "gettime", CTLTYPE_STRUCT }, \ 298 } 299 300 #ifndef KERNEL 301 #include <sys/cdefs.h> 302 303 __BEGIN_DECLS 304 extern int ntp_gettime __P((struct ntptimeval *)); 305 extern int ntp_adjtime __P((struct timex *)); 306 __END_DECLS 307 308 #endif /* not KERNEL */ 309 310 #endif /* __FreeBSD__ */ 311 #endif /* _SYS_TIMEX_H_ */ 312