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 * 2004-08-12 Christoph Lameter 51 * Reworked time interpolation logic 52 */ 53 #ifndef _LINUX_TIMEX_H 54 #define _LINUX_TIMEX_H 55 56 #include <linux/compiler.h> 57 #include <linux/time.h> 58 59 #include <asm/param.h> 60 #include <asm/timex.h> 61 62 /* 63 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen 64 * for a slightly underdamped convergence characteristic. SHIFT_KH 65 * establishes the damping of the FLL and is chosen by wisdom and black 66 * art. 67 * 68 * MAXTC establishes the maximum time constant of the PLL. With the 69 * SHIFT_KG and SHIFT_KF values given and a time constant range from 70 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, 71 * respectively. 72 */ 73 #define SHIFT_KG 6 /* phase factor (shift) */ 74 #define SHIFT_KF 16 /* PLL frequency factor (shift) */ 75 #define SHIFT_KH 2 /* FLL frequency factor (shift) */ 76 #define MAXTC 6 /* maximum time constant (shift) */ 77 78 /* 79 * The SHIFT_SCALE define establishes the decimal point of the time_phase 80 * variable which serves as an extension to the low-order bits of the 81 * system clock variable. The SHIFT_UPDATE define establishes the decimal 82 * point of the time_offset variable which represents the current offset 83 * with respect to standard time. The FINENSEC define represents 1 nsec in 84 * scaled units. 85 * 86 * SHIFT_USEC defines the scaling (shift) of the time_freq and 87 * time_tolerance variables, which represent the current frequency 88 * offset and maximum frequency tolerance. 89 * 90 * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable. 91 */ 92 #define SHIFT_SCALE 22 /* phase scale (shift) */ 93 #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */ 94 #define SHIFT_USEC 16 /* frequency offset scale (shift) */ 95 #define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */ 96 97 #define MAXPHASE 512000L /* max phase error (us) */ 98 #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ 99 #define MINSEC 16L /* min interval between updates (s) */ 100 #define MAXSEC 1200L /* max interval between updates (s) */ 101 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ 102 103 /* 104 * syscall interface - used (mainly by NTP daemon) 105 * to discipline kernel clock oscillator 106 */ 107 struct timex { 108 unsigned int modes; /* mode selector */ 109 long offset; /* time offset (usec) */ 110 long freq; /* frequency offset (scaled ppm) */ 111 long maxerror; /* maximum error (usec) */ 112 long esterror; /* estimated error (usec) */ 113 int status; /* clock command/status */ 114 long constant; /* pll time constant */ 115 long precision; /* clock precision (usec) (read only) */ 116 long tolerance; /* clock frequency tolerance (ppm) 117 * (read only) 118 */ 119 struct timeval time; /* (read only) */ 120 long tick; /* (modified) usecs between clock ticks */ 121 122 long ppsfreq; /* pps frequency (scaled ppm) (ro) */ 123 long jitter; /* pps jitter (us) (ro) */ 124 int shift; /* interval duration (s) (shift) (ro) */ 125 long stabil; /* pps stability (scaled ppm) (ro) */ 126 long jitcnt; /* jitter limit exceeded (ro) */ 127 long calcnt; /* calibration intervals (ro) */ 128 long errcnt; /* calibration errors (ro) */ 129 long stbcnt; /* stability limit exceeded (ro) */ 130 131 int :32; int :32; int :32; int :32; 132 int :32; int :32; int :32; int :32; 133 int :32; int :32; int :32; int :32; 134 }; 135 136 /* 137 * Mode codes (timex.mode) 138 */ 139 #define ADJ_OFFSET 0x0001 /* time offset */ 140 #define ADJ_FREQUENCY 0x0002 /* frequency offset */ 141 #define ADJ_MAXERROR 0x0004 /* maximum time error */ 142 #define ADJ_ESTERROR 0x0008 /* estimated time error */ 143 #define ADJ_STATUS 0x0010 /* clock status */ 144 #define ADJ_TIMECONST 0x0020 /* pll time constant */ 145 #define ADJ_TICK 0x4000 /* tick value */ 146 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ 147 148 /* xntp 3.4 compatibility names */ 149 #define MOD_OFFSET ADJ_OFFSET 150 #define MOD_FREQUENCY ADJ_FREQUENCY 151 #define MOD_MAXERROR ADJ_MAXERROR 152 #define MOD_ESTERROR ADJ_ESTERROR 153 #define MOD_STATUS ADJ_STATUS 154 #define MOD_TIMECONST ADJ_TIMECONST 155 #define MOD_CLKB ADJ_TICK 156 #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ 157 158 159 /* 160 * Status codes (timex.status) 161 */ 162 #define STA_PLL 0x0001 /* enable PLL updates (rw) */ 163 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ 164 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ 165 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ 166 167 #define STA_INS 0x0010 /* insert leap (rw) */ 168 #define STA_DEL 0x0020 /* delete leap (rw) */ 169 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ 170 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ 171 172 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ 173 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ 174 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ 175 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ 176 177 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ 178 179 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ 180 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ 181 182 /* 183 * Clock states (time_state) 184 */ 185 #define TIME_OK 0 /* clock synchronized, no leap second */ 186 #define TIME_INS 1 /* insert leap second */ 187 #define TIME_DEL 2 /* delete leap second */ 188 #define TIME_OOP 3 /* leap second in progress */ 189 #define TIME_WAIT 4 /* leap second has occurred */ 190 #define TIME_ERROR 5 /* clock not synchronized */ 191 #define TIME_BAD TIME_ERROR /* bw compat */ 192 193 #ifdef __KERNEL__ 194 /* 195 * kernel variables 196 * Note: maximum error = NTP synch distance = dispersion + delay / 2; 197 * estimated error = NTP dispersion. 198 */ 199 extern unsigned long tick_usec; /* USER_HZ period (usec) */ 200 extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ 201 extern int tickadj; /* amount of adjustment per tick */ 202 203 /* 204 * phase-lock loop variables 205 */ 206 extern int time_state; /* clock status */ 207 extern int time_status; /* clock synchronization status bits */ 208 extern long time_offset; /* time adjustment (us) */ 209 extern long time_constant; /* pll time constant */ 210 extern long time_tolerance; /* frequency tolerance (ppm) */ 211 extern long time_precision; /* clock precision (us) */ 212 extern long time_maxerror; /* maximum error */ 213 extern long time_esterror; /* estimated error */ 214 215 extern long time_freq; /* frequency offset (scaled ppm) */ 216 extern long time_reftime; /* time at last adjustment (s) */ 217 218 extern long time_adjust; /* The amount of adjtime left */ 219 extern long time_next_adjust; /* Value for time_adjust at next tick */ 220 221 /** 222 * ntp_clear - Clears the NTP state variables 223 * 224 * Must be called while holding a write on the xtime_lock 225 */ 226 static inline void ntp_clear(void) 227 { 228 time_adjust = 0; /* stop active adjtime() */ 229 time_status |= STA_UNSYNC; 230 time_maxerror = NTP_PHASE_LIMIT; 231 time_esterror = NTP_PHASE_LIMIT; 232 } 233 234 /** 235 * ntp_synced - Returns 1 if the NTP status is not UNSYNC 236 * 237 */ 238 static inline int ntp_synced(void) 239 { 240 return !(time_status & STA_UNSYNC); 241 } 242 243 /* Required to safely shift negative values */ 244 #define shift_right(x, s) ({ \ 245 __typeof__(x) __x = (x); \ 246 __typeof__(s) __s = (s); \ 247 __x < 0 ? -(-__x >> __s) : __x >> __s; \ 248 }) 249 250 251 #ifdef CONFIG_TIME_INTERPOLATION 252 253 #define TIME_SOURCE_CPU 0 254 #define TIME_SOURCE_MMIO64 1 255 #define TIME_SOURCE_MMIO32 2 256 #define TIME_SOURCE_FUNCTION 3 257 258 /* For proper operations time_interpolator clocks must run slightly slower 259 * than the standard clock since the interpolator may only correct by having 260 * time jump forward during a tick. A slower clock is usually a side effect 261 * of the integer divide of the nanoseconds in a second by the frequency. 262 * The accuracy of the division can be increased by specifying a shift. 263 * However, this may cause the clock not to be slow enough. 264 * The interpolator will self-tune the clock by slowing down if no 265 * resets occur or speeding up if the time jumps per analysis cycle 266 * become too high. 267 * 268 * Setting jitter compensates for a fluctuating timesource by comparing 269 * to the last value read from the timesource to insure that an earlier value 270 * is not returned by a later call. The price to pay 271 * for the compensation is that the timer routines are not as scalable anymore. 272 */ 273 274 struct time_interpolator { 275 u16 source; /* time source flags */ 276 u8 shift; /* increases accuracy of multiply by shifting. */ 277 /* Note that bits may be lost if shift is set too high */ 278 u8 jitter; /* if set compensate for fluctuations */ 279 u32 nsec_per_cyc; /* set by register_time_interpolator() */ 280 void *addr; /* address of counter or function */ 281 u64 mask; /* mask the valid bits of the counter */ 282 unsigned long offset; /* nsec offset at last update of interpolator */ 283 u64 last_counter; /* counter value in units of the counter at last update */ 284 u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ 285 u64 frequency; /* frequency in counts/second */ 286 long drift; /* drift in parts-per-million (or -1) */ 287 unsigned long skips; /* skips forward */ 288 unsigned long ns_skipped; /* nanoseconds skipped */ 289 struct time_interpolator *next; 290 }; 291 292 extern void register_time_interpolator(struct time_interpolator *); 293 extern void unregister_time_interpolator(struct time_interpolator *); 294 extern void time_interpolator_reset(void); 295 extern unsigned long time_interpolator_get_offset(void); 296 297 #else /* !CONFIG_TIME_INTERPOLATION */ 298 299 static inline void 300 time_interpolator_reset(void) 301 { 302 } 303 304 #endif /* !CONFIG_TIME_INTERPOLATION */ 305 306 #define TICK_LENGTH_SHIFT 32 307 308 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */ 309 extern u64 current_tick_length(void); 310 311 extern int do_adjtimex(struct timex *); 312 313 #endif /* KERNEL */ 314 315 #endif /* LINUX_TIMEX_H */ 316