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 61 /* 62 * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen 63 * for a slightly underdamped convergence characteristic. SHIFT_KH 64 * establishes the damping of the FLL and is chosen by wisdom and black 65 * art. 66 * 67 * MAXTC establishes the maximum time constant of the PLL. With the 68 * SHIFT_KG and SHIFT_KF values given and a time constant range from 69 * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, 70 * respectively. 71 */ 72 #define SHIFT_PLL 4 /* PLL frequency factor (shift) */ 73 #define SHIFT_FLL 2 /* FLL frequency factor (shift) */ 74 #define MAXTC 10 /* maximum time constant (shift) */ 75 76 /* 77 * The SHIFT_UPDATE define establishes the decimal point of the 78 * time_offset variable which represents the current offset with 79 * respect to standard time. 80 * 81 * SHIFT_USEC defines the scaling (shift) of the time_freq and 82 * time_tolerance variables, which represent the current frequency 83 * offset and maximum frequency tolerance. 84 */ 85 #define SHIFT_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */ 86 #define SHIFT_USEC 16 /* frequency offset scale (shift) */ 87 #define SHIFT_NSEC 12 /* kernel frequency offset scale */ 88 89 #define MAXPHASE 512000L /* max phase error (us) */ 90 #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ 91 #define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */ 92 #define MINSEC 256 /* min interval between updates (s) */ 93 #define MAXSEC 2048 /* max interval between updates (s) */ 94 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ 95 96 /* 97 * syscall interface - used (mainly by NTP daemon) 98 * to discipline kernel clock oscillator 99 */ 100 struct timex { 101 unsigned int modes; /* mode selector */ 102 long offset; /* time offset (usec) */ 103 long freq; /* frequency offset (scaled ppm) */ 104 long maxerror; /* maximum error (usec) */ 105 long esterror; /* estimated error (usec) */ 106 int status; /* clock command/status */ 107 long constant; /* pll time constant */ 108 long precision; /* clock precision (usec) (read only) */ 109 long tolerance; /* clock frequency tolerance (ppm) 110 * (read only) 111 */ 112 struct timeval time; /* (read only) */ 113 long tick; /* (modified) usecs between clock ticks */ 114 115 long ppsfreq; /* pps frequency (scaled ppm) (ro) */ 116 long jitter; /* pps jitter (us) (ro) */ 117 int shift; /* interval duration (s) (shift) (ro) */ 118 long stabil; /* pps stability (scaled ppm) (ro) */ 119 long jitcnt; /* jitter limit exceeded (ro) */ 120 long calcnt; /* calibration intervals (ro) */ 121 long errcnt; /* calibration errors (ro) */ 122 long stbcnt; /* stability limit exceeded (ro) */ 123 124 int :32; int :32; int :32; int :32; 125 int :32; int :32; int :32; int :32; 126 int :32; int :32; int :32; int :32; 127 }; 128 129 /* 130 * Mode codes (timex.mode) 131 */ 132 #define ADJ_OFFSET 0x0001 /* time offset */ 133 #define ADJ_FREQUENCY 0x0002 /* frequency offset */ 134 #define ADJ_MAXERROR 0x0004 /* maximum time error */ 135 #define ADJ_ESTERROR 0x0008 /* estimated time error */ 136 #define ADJ_STATUS 0x0010 /* clock status */ 137 #define ADJ_TIMECONST 0x0020 /* pll time constant */ 138 #define ADJ_TICK 0x4000 /* tick value */ 139 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ 140 141 /* xntp 3.4 compatibility names */ 142 #define MOD_OFFSET ADJ_OFFSET 143 #define MOD_FREQUENCY ADJ_FREQUENCY 144 #define MOD_MAXERROR ADJ_MAXERROR 145 #define MOD_ESTERROR ADJ_ESTERROR 146 #define MOD_STATUS ADJ_STATUS 147 #define MOD_TIMECONST ADJ_TIMECONST 148 #define MOD_CLKB ADJ_TICK 149 #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ 150 151 152 /* 153 * Status codes (timex.status) 154 */ 155 #define STA_PLL 0x0001 /* enable PLL updates (rw) */ 156 #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ 157 #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ 158 #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ 159 160 #define STA_INS 0x0010 /* insert leap (rw) */ 161 #define STA_DEL 0x0020 /* delete leap (rw) */ 162 #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ 163 #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ 164 165 #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ 166 #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ 167 #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ 168 #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ 169 170 #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ 171 172 #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ 173 STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ 174 175 /* 176 * Clock states (time_state) 177 */ 178 #define TIME_OK 0 /* clock synchronized, no leap second */ 179 #define TIME_INS 1 /* insert leap second */ 180 #define TIME_DEL 2 /* delete leap second */ 181 #define TIME_OOP 3 /* leap second in progress */ 182 #define TIME_WAIT 4 /* leap second has occurred */ 183 #define TIME_ERROR 5 /* clock not synchronized */ 184 #define TIME_BAD TIME_ERROR /* bw compat */ 185 186 #ifdef __KERNEL__ 187 #include <asm/timex.h> 188 189 /* 190 * kernel variables 191 * Note: maximum error = NTP synch distance = dispersion + delay / 2; 192 * estimated error = NTP dispersion. 193 */ 194 extern unsigned long tick_usec; /* USER_HZ period (usec) */ 195 extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ 196 extern int tickadj; /* amount of adjustment per tick */ 197 198 /* 199 * phase-lock loop variables 200 */ 201 extern int time_status; /* clock synchronization status bits */ 202 extern long time_maxerror; /* maximum error */ 203 extern long time_esterror; /* estimated error */ 204 205 extern long time_freq; /* frequency offset (scaled ppm) */ 206 207 extern long time_adjust; /* The amount of adjtime left */ 208 209 extern void ntp_clear(void); 210 211 /** 212 * ntp_synced - Returns 1 if the NTP status is not UNSYNC 213 * 214 */ 215 static inline int ntp_synced(void) 216 { 217 return !(time_status & STA_UNSYNC); 218 } 219 220 /* Required to safely shift negative values */ 221 #define shift_right(x, s) ({ \ 222 __typeof__(x) __x = (x); \ 223 __typeof__(s) __s = (s); \ 224 __x < 0 ? -(-__x >> __s) : __x >> __s; \ 225 }) 226 227 228 #ifdef CONFIG_TIME_INTERPOLATION 229 230 #define TIME_SOURCE_CPU 0 231 #define TIME_SOURCE_MMIO64 1 232 #define TIME_SOURCE_MMIO32 2 233 #define TIME_SOURCE_FUNCTION 3 234 235 /* For proper operations time_interpolator clocks must run slightly slower 236 * than the standard clock since the interpolator may only correct by having 237 * time jump forward during a tick. A slower clock is usually a side effect 238 * of the integer divide of the nanoseconds in a second by the frequency. 239 * The accuracy of the division can be increased by specifying a shift. 240 * However, this may cause the clock not to be slow enough. 241 * The interpolator will self-tune the clock by slowing down if no 242 * resets occur or speeding up if the time jumps per analysis cycle 243 * become too high. 244 * 245 * Setting jitter compensates for a fluctuating timesource by comparing 246 * to the last value read from the timesource to insure that an earlier value 247 * is not returned by a later call. The price to pay 248 * for the compensation is that the timer routines are not as scalable anymore. 249 */ 250 251 struct time_interpolator { 252 u16 source; /* time source flags */ 253 u8 shift; /* increases accuracy of multiply by shifting. */ 254 /* Note that bits may be lost if shift is set too high */ 255 u8 jitter; /* if set compensate for fluctuations */ 256 u32 nsec_per_cyc; /* set by register_time_interpolator() */ 257 void *addr; /* address of counter or function */ 258 cycles_t mask; /* mask the valid bits of the counter */ 259 unsigned long offset; /* nsec offset at last update of interpolator */ 260 u64 last_counter; /* counter value in units of the counter at last update */ 261 cycles_t last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ 262 u64 frequency; /* frequency in counts/second */ 263 long drift; /* drift in parts-per-million (or -1) */ 264 unsigned long skips; /* skips forward */ 265 unsigned long ns_skipped; /* nanoseconds skipped */ 266 struct time_interpolator *next; 267 }; 268 269 extern void register_time_interpolator(struct time_interpolator *); 270 extern void unregister_time_interpolator(struct time_interpolator *); 271 extern void time_interpolator_reset(void); 272 extern unsigned long time_interpolator_get_offset(void); 273 extern void time_interpolator_update(long delta_nsec); 274 275 #else /* !CONFIG_TIME_INTERPOLATION */ 276 277 static inline void time_interpolator_reset(void) 278 { 279 } 280 281 static inline void time_interpolator_update(long delta_nsec) 282 { 283 } 284 285 #endif /* !CONFIG_TIME_INTERPOLATION */ 286 287 #define TICK_LENGTH_SHIFT 32 288 289 #ifdef CONFIG_NO_HZ 290 #define NTP_INTERVAL_FREQ (2) 291 #else 292 #define NTP_INTERVAL_FREQ (HZ) 293 #endif 294 #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ) 295 296 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */ 297 extern u64 current_tick_length(void); 298 299 extern void second_overflow(void); 300 extern void update_ntp_one_tick(void); 301 extern int do_adjtimex(struct timex *); 302 303 /* Don't use! Compatibility define for existing users. */ 304 #define tickadj (500/HZ ? : 1) 305 306 #endif /* KERNEL */ 307 308 #endif /* LINUX_TIMEX_H */ 309