1/***************************************************************************** 2 * * 3 * Copyright (c) David L. Mills 1993 * 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 * 29 Dec 97 Russell King 21 * Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h 22 * for ARM machines 23 * 24 * 9 Jan 97 Adrian Sun 25 * Shifted LATCH define to allow access to alpha machines. 26 * 27 * 26 Sep 94 David L. Mills 28 * Added defines for hybrid phase/frequency-lock loop. 29 * 30 * 19 Mar 94 David L. Mills 31 * Moved defines from kernel routines to header file and added new 32 * defines for PPS phase-lock loop. 33 * 34 * 20 Feb 94 David L. Mills 35 * Revised status codes and structures for external clock and PPS 36 * signal discipline. 37 * 38 * 28 Nov 93 David L. Mills 39 * Adjusted parameters to improve stability and increase poll 40 * interval. 41 * 42 * 17 Sep 93 David L. Mills 43 * Created file $NTP/include/sys/timex.h 44 * 07 Oct 93 Torsten Duwe 45 * Derived linux/timex.h 46 * 1995-08-13 Torsten Duwe 47 * kernel PLL updated to 1994-12-13 specs (rfc-1589) 48 * 1997-08-30 Ulrich Windl 49 * Added new constant NTP_PHASE_LIMIT 50 */ 51#ifndef _LINUX_TIMEX_H 52#define _LINUX_TIMEX_H 53 54#include <linux/config.h> 55#include <linux/compiler.h> 56 57#include <asm/param.h> 58 59/* 60 * The following defines establish the engineering parameters of the PLL 61 * model. The HZ variable establishes the timer interrupt frequency, 100 Hz 62 * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the 63 * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the 64 * nearest power of two in order to avoid hardware multiply operations. 65 */ 66#if HZ >= 12 && HZ < 24 67# define SHIFT_HZ 4 68#elif HZ >= 24 && HZ < 48 69# define SHIFT_HZ 5 70#elif HZ >= 48 && HZ < 96 71# define SHIFT_HZ 6 72#elif HZ >= 96 && HZ < 192 73# define SHIFT_HZ 7 74#elif HZ >= 192 && HZ < 384 75# define SHIFT_HZ 8 76#elif HZ >= 384 && HZ < 768 77# define SHIFT_HZ 9 78#elif HZ >= 768 && HZ < 1536 79# define SHIFT_HZ 10 80#else 81# error You lose. 82#endif 83 84/* 85 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen 86 * for a slightly underdamped convergence characteristic. SHIFT_KH 87 * establishes the damping of the FLL and is chosen by wisdom and black 88 * art. 89 * 90 * MAXTC establishes the maximum time constant of the PLL. With the 91 * SHIFT_KG and SHIFT_KF values given and a time constant range from 92 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, 93 * respectively. 94 */ 95#define SHIFT_KG 6 /* phase factor (shift) */ 96#define SHIFT_KF 16 /* PLL frequency factor (shift) */ 97#define SHIFT_KH 2 /* FLL frequency factor (shift) */ 98#define MAXTC 6 /* maximum time constant (shift) */ 99 100/* 101 * The SHIFT_SCALE define establishes the decimal point of the time_phase 102 * variable which serves as an extension to the low-order bits of the 103 * system clock variable. The SHIFT_UPDATE define establishes the decimal 104 * point of the time_offset variable which represents the current offset 105 * with respect to standard time. The FINENSEC define represents 1 nsec in 106 * scaled units. 107 * 108 * SHIFT_USEC defines the scaling (shift) of the time_freq and 109 * time_tolerance variables, which represent the current frequency 110 * offset and maximum frequency tolerance. 111 * 112 * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable. 113 */ 114#define SHIFT_SCALE 22 /* phase scale (shift) */ 115#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */ 116#define SHIFT_USEC 16 /* frequency offset scale (shift) */ 117#define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */ 118 119#define MAXPHASE 512000L /* max phase error (us) */ 120#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ 121#define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */ 122#define MINSEC 16L /* min interval between updates (s) */ 123#define MAXSEC 1200L /* max interval between updates (s) */ 124#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ 125 126/* 127 * The following defines are used only if a pulse-per-second (PPS) 128 * signal is available and connected via a modem control lead, such as 129 * produced by the optional ppsclock feature incorporated in the Sun 130 * asynch driver. They establish the design parameters of the frequency- 131 * lock loop used to discipline the CPU clock oscillator to the PPS 132 * signal. 133 * 134 * PPS_AVG is the averaging factor for the frequency loop, as well as 135 * the time and frequency dispersion. 136 * 137 * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum 138 * calibration intervals, respectively, in seconds as a power of two. 139 * 140 * PPS_VALID is the maximum interval before the PPS signal is considered 141 * invalid and protocol updates used directly instead. 142 * 143 * MAXGLITCH is the maximum interval before a time offset of more than 144 * MAXTIME is believed. 145 */ 146#define PPS_AVG 2 /* pps averaging constant (shift) */ 147#define PPS_SHIFT 2 /* min interval duration (s) (shift) */ 148#define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */ 149#define PPS_VALID 120 /* pps signal watchdog max (s) */ 150#define MAXGLITCH 30 /* pps signal glitch max (s) */ 151 152/* 153 * Pick up the architecture specific timex specifications 154 */ 155#include <asm/timex.h> 156 157/* LATCH is used in the interval timer and ftape setup. */ 158#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ 159 160/* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can 161 * improve accuracy by shifting LSH bits, hence calculating: 162 * (NOM << LSH) / DEN 163 * This however means trouble for large NOM, because (NOM << LSH) may no 164 * longer fit in 32 bits. The following way of calculating this gives us 165 * some slack, under the following conditions: 166 * - (NOM / DEN) fits in (32 - LSH) bits. 167 * - (NOM % DEN) fits in (32 - LSH) bits. 168 */ 169#define SH_DIV(NOM,DEN,LSH) ( ((NOM / DEN) << LSH) \ 170 + (((NOM % DEN) << LSH) + DEN / 2) / DEN) 171 172/* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */ 173#define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8)) 174 175/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */ 176#define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8)) 177 178/* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ 179#define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) 180 181/* TICK_USEC_TO_NSEC is the time between ticks in nsec assuming real ACTHZ and */ 182/* a value TUSEC for TICK_USEC (can be set bij adjtimex) */ 183#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV (TUSEC * USER_HZ * 1000, ACTHZ, 8)) 184 185 186#include <linux/time.h> 187/* 188 * syscall interface - used (mainly by NTP daemon) 189 * to discipline kernel clock oscillator 190 */ 191struct timex { 192 unsigned int modes; /* mode selector */ 193 long offset; /* time offset (usec) */ 194 long freq; /* frequency offset (scaled ppm) */ 195 long maxerror; /* maximum error (usec) */ 196 long esterror; /* estimated error (usec) */ 197 int status; /* clock command/status */ 198 long constant; /* pll time constant */ 199 long precision; /* clock precision (usec) (read only) */ 200 long tolerance; /* clock frequency tolerance (ppm) 201 * (read only) 202 */ 203 struct timeval time; /* (read only) */ 204 long tick; /* (modified) usecs between clock ticks */ 205 206 long ppsfreq; /* pps frequency (scaled ppm) (ro) */ 207 long jitter; /* pps jitter (us) (ro) */ 208 int shift; /* interval duration (s) (shift) (ro) */ 209 long stabil; /* pps stability (scaled ppm) (ro) */ 210 long jitcnt; /* jitter limit exceeded (ro) */ 211 long calcnt; /* calibration intervals (ro) */ 212 long errcnt; /* calibration errors (ro) */ 213 long stbcnt; /* stability limit exceeded (ro) */ 214 215 int :32; int :32; int :32; int :32; 216 int :32; int :32; int :32; int :32; 217 int :32; int :32; int :32; int :32; 218}; 219 220/* 221 * Mode codes (timex.mode) 222 */ 223#define ADJ_OFFSET 0x0001 /* time offset */ 224#define ADJ_FREQUENCY 0x0002 /* frequency offset */ 225#define ADJ_MAXERROR 0x0004 /* maximum time error */ 226#define ADJ_ESTERROR 0x0008 /* estimated time error */ 227#define ADJ_STATUS 0x0010 /* clock status */ 228#define ADJ_TIMECONST 0x0020 /* pll time constant */ 229#define ADJ_TICK 0x4000 /* tick value */ 230#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ 231 232/* xntp 3.4 compatibility names */ 233#define MOD_OFFSET ADJ_OFFSET 234#define MOD_FREQUENCY ADJ_FREQUENCY 235#define MOD_MAXERROR ADJ_MAXERROR 236#define MOD_ESTERROR ADJ_ESTERROR 237#define MOD_STATUS ADJ_STATUS 238#define MOD_TIMECONST ADJ_TIMECONST 239#define MOD_CLKB ADJ_TICK 240#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ 241 242 243/* 244 * Status codes (timex.status) 245 */ 246#define STA_PLL 0x0001 /* enable PLL updates (rw) */ 247#define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ 248#define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ 249#define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ 250 251#define STA_INS 0x0010 /* insert leap (rw) */ 252#define STA_DEL 0x0020 /* delete leap (rw) */ 253#define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ 254#define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ 255 256#define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ 257#define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ 258#define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ 259#define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ 260 261#define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ 262 263#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ 264 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ 265 266/* 267 * Clock states (time_state) 268 */ 269#define TIME_OK 0 /* clock synchronized, no leap second */ 270#define TIME_INS 1 /* insert leap second */ 271#define TIME_DEL 2 /* delete leap second */ 272#define TIME_OOP 3 /* leap second in progress */ 273#define TIME_WAIT 4 /* leap second has occurred */ 274#define TIME_ERROR 5 /* clock not synchronized */ 275#define TIME_BAD TIME_ERROR /* bw compat */ 276 277#ifdef __KERNEL__ 278/* 279 * kernel variables 280 * Note: maximum error = NTP synch distance = dispersion + delay / 2; 281 * estimated error = NTP dispersion. 282 */ 283extern unsigned long tick_usec; /* USER_HZ period (usec) */ 284extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ 285extern int tickadj; /* amount of adjustment per tick */ 286 287/* 288 * phase-lock loop variables 289 */ 290extern int time_state; /* clock status */ 291extern int time_status; /* clock synchronization status bits */ 292extern long time_offset; /* time adjustment (us) */ 293extern long time_constant; /* pll time constant */ 294extern long time_tolerance; /* frequency tolerance (ppm) */ 295extern long time_precision; /* clock precision (us) */ 296extern long time_maxerror; /* maximum error */ 297extern long time_esterror; /* estimated error */ 298 299extern long time_phase; /* phase offset (scaled us) */ 300extern long time_freq; /* frequency offset (scaled ppm) */ 301extern long time_adj; /* tick adjust (scaled 1 / HZ) */ 302extern long time_reftime; /* time at last adjustment (s) */ 303 304extern long time_adjust; /* The amount of adjtime left */ 305extern long time_next_adjust; /* Value for time_adjust at next tick */ 306 307/* interface variables pps->timer interrupt */ 308extern long pps_offset; /* pps time offset (us) */ 309extern long pps_jitter; /* time dispersion (jitter) (us) */ 310extern long pps_freq; /* frequency offset (scaled ppm) */ 311extern long pps_stabil; /* frequency dispersion (scaled ppm) */ 312extern long pps_valid; /* pps signal watchdog counter */ 313 314/* interface variables pps->adjtimex */ 315extern int pps_shift; /* interval duration (s) (shift) */ 316extern long pps_jitcnt; /* jitter limit exceeded */ 317extern long pps_calcnt; /* calibration intervals */ 318extern long pps_errcnt; /* calibration errors */ 319extern long pps_stbcnt; /* stability limit exceeded */ 320 321#ifdef CONFIG_TIME_INTERPOLATION 322 323struct time_interpolator { 324 /* cache-hot stuff first: */ 325 unsigned long (*get_offset) (void); 326 void (*update) (long); 327 void (*reset) (void); 328 329 /* cache-cold stuff follows here: */ 330 struct time_interpolator *next; 331 unsigned long frequency; /* frequency in counts/second */ 332 long drift; /* drift in parts-per-million (or -1) */ 333}; 334 335extern volatile unsigned long last_nsec_offset; 336#ifndef __HAVE_ARCH_CMPXCHG 337extern spin_lock_t last_nsec_offset_lock; 338#endif 339extern struct time_interpolator *time_interpolator; 340 341extern void register_time_interpolator(struct time_interpolator *); 342extern void unregister_time_interpolator(struct time_interpolator *); 343 344/* Called with xtime WRITE-lock acquired. */ 345static inline void 346time_interpolator_update(long delta_nsec) 347{ 348 struct time_interpolator *ti = time_interpolator; 349 350 if (last_nsec_offset > 0) { 351#ifdef __HAVE_ARCH_CMPXCHG 352 unsigned long new, old; 353 354 do { 355 old = last_nsec_offset; 356 if (old > delta_nsec) 357 new = old - delta_nsec; 358 else 359 new = 0; 360 } while (cmpxchg(&last_nsec_offset, old, new) != old); 361#else 362 /* 363 * This really hurts, because it serializes gettimeofday(), but without an 364 * atomic single-word compare-and-exchange, there isn't all that much else 365 * we can do. 366 */ 367 spin_lock(&last_nsec_offset_lock); 368 { 369 last_nsec_offset -= min(last_nsec_offset, delta_nsec); 370 } 371 spin_unlock(&last_nsec_offset_lock); 372#endif 373 } 374 375 if (ti) 376 (*ti->update)(delta_nsec); 377} 378 379/* Called with xtime WRITE-lock acquired. */ 380static inline void 381time_interpolator_reset(void) 382{ 383 struct time_interpolator *ti = time_interpolator; 384 385 last_nsec_offset = 0; 386 if (ti) 387 (*ti->reset)(); 388} 389 390/* Called with xtime READ-lock acquired. */ 391static inline unsigned long 392time_interpolator_get_offset(void) 393{ 394 struct time_interpolator *ti = time_interpolator; 395 if (ti) 396 return (*ti->get_offset)(); 397 return last_nsec_offset; 398} 399 400#else /* !CONFIG_TIME_INTERPOLATION */ 401 402static inline void 403time_interpolator_update(long delta_nsec) 404{ 405} 406 407static inline void 408time_interpolator_reset(void) 409{ 410} 411 412static inline unsigned long 413time_interpolator_get_offset(void) 414{ 415 return 0; 416} 417 418#endif /* !CONFIG_TIME_INTERPOLATION */ 419 420#endif /* KERNEL */ 421 422#endif /* LINUX_TIMEX_H */ 423