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