Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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/config.h> |
| 57 | #include <linux/compiler.h> |
| 58 | #include <linux/time.h> |
| 59 | |
| 60 | #include <asm/param.h> |
| 61 | #include <asm/timex.h> |
| 62 | |
| 63 | /* |
| 64 | * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen |
| 65 | * for a slightly underdamped convergence characteristic. SHIFT_KH |
| 66 | * establishes the damping of the FLL and is chosen by wisdom and black |
| 67 | * art. |
| 68 | * |
| 69 | * MAXTC establishes the maximum time constant of the PLL. With the |
| 70 | * SHIFT_KG and SHIFT_KF values given and a time constant range from |
| 71 | * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, |
| 72 | * respectively. |
| 73 | */ |
| 74 | #define SHIFT_KG 6 /* phase factor (shift) */ |
| 75 | #define SHIFT_KF 16 /* PLL frequency factor (shift) */ |
| 76 | #define SHIFT_KH 2 /* FLL frequency factor (shift) */ |
| 77 | #define MAXTC 6 /* maximum time constant (shift) */ |
| 78 | |
| 79 | /* |
| 80 | * The SHIFT_SCALE define establishes the decimal point of the time_phase |
| 81 | * variable which serves as an extension to the low-order bits of the |
| 82 | * system clock variable. The SHIFT_UPDATE define establishes the decimal |
| 83 | * point of the time_offset variable which represents the current offset |
| 84 | * with respect to standard time. The FINENSEC define represents 1 nsec in |
| 85 | * scaled units. |
| 86 | * |
| 87 | * SHIFT_USEC defines the scaling (shift) of the time_freq and |
| 88 | * time_tolerance variables, which represent the current frequency |
| 89 | * offset and maximum frequency tolerance. |
| 90 | * |
| 91 | * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable. |
| 92 | */ |
| 93 | #define SHIFT_SCALE 22 /* phase scale (shift) */ |
| 94 | #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */ |
| 95 | #define SHIFT_USEC 16 /* frequency offset scale (shift) */ |
| 96 | #define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */ |
| 97 | |
| 98 | #define MAXPHASE 512000L /* max phase error (us) */ |
| 99 | #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ |
| 100 | #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */ |
| 101 | #define MINSEC 16L /* min interval between updates (s) */ |
| 102 | #define MAXSEC 1200L /* max interval between updates (s) */ |
| 103 | #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ |
| 104 | |
| 105 | /* |
| 106 | * The following defines are used only if a pulse-per-second (PPS) |
| 107 | * signal is available and connected via a modem control lead, such as |
| 108 | * produced by the optional ppsclock feature incorporated in the Sun |
| 109 | * asynch driver. They establish the design parameters of the frequency- |
| 110 | * lock loop used to discipline the CPU clock oscillator to the PPS |
| 111 | * signal. |
| 112 | * |
| 113 | * PPS_AVG is the averaging factor for the frequency loop, as well as |
| 114 | * the time and frequency dispersion. |
| 115 | * |
| 116 | * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum |
| 117 | * calibration intervals, respectively, in seconds as a power of two. |
| 118 | * |
| 119 | * PPS_VALID is the maximum interval before the PPS signal is considered |
| 120 | * invalid and protocol updates used directly instead. |
| 121 | * |
| 122 | * MAXGLITCH is the maximum interval before a time offset of more than |
| 123 | * MAXTIME is believed. |
| 124 | */ |
| 125 | #define PPS_AVG 2 /* pps averaging constant (shift) */ |
| 126 | #define PPS_SHIFT 2 /* min interval duration (s) (shift) */ |
| 127 | #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */ |
| 128 | #define PPS_VALID 120 /* pps signal watchdog max (s) */ |
| 129 | #define MAXGLITCH 30 /* pps signal glitch max (s) */ |
| 130 | |
| 131 | /* |
| 132 | * syscall interface - used (mainly by NTP daemon) |
| 133 | * to discipline kernel clock oscillator |
| 134 | */ |
| 135 | struct timex { |
| 136 | unsigned int modes; /* mode selector */ |
| 137 | long offset; /* time offset (usec) */ |
| 138 | long freq; /* frequency offset (scaled ppm) */ |
| 139 | long maxerror; /* maximum error (usec) */ |
| 140 | long esterror; /* estimated error (usec) */ |
| 141 | int status; /* clock command/status */ |
| 142 | long constant; /* pll time constant */ |
| 143 | long precision; /* clock precision (usec) (read only) */ |
| 144 | long tolerance; /* clock frequency tolerance (ppm) |
| 145 | * (read only) |
| 146 | */ |
| 147 | struct timeval time; /* (read only) */ |
| 148 | long tick; /* (modified) usecs between clock ticks */ |
| 149 | |
| 150 | long ppsfreq; /* pps frequency (scaled ppm) (ro) */ |
| 151 | long jitter; /* pps jitter (us) (ro) */ |
| 152 | int shift; /* interval duration (s) (shift) (ro) */ |
| 153 | long stabil; /* pps stability (scaled ppm) (ro) */ |
| 154 | long jitcnt; /* jitter limit exceeded (ro) */ |
| 155 | long calcnt; /* calibration intervals (ro) */ |
| 156 | long errcnt; /* calibration errors (ro) */ |
| 157 | long stbcnt; /* stability limit exceeded (ro) */ |
| 158 | |
| 159 | int :32; int :32; int :32; int :32; |
| 160 | int :32; int :32; int :32; int :32; |
| 161 | int :32; int :32; int :32; int :32; |
| 162 | }; |
| 163 | |
| 164 | /* |
| 165 | * Mode codes (timex.mode) |
| 166 | */ |
| 167 | #define ADJ_OFFSET 0x0001 /* time offset */ |
| 168 | #define ADJ_FREQUENCY 0x0002 /* frequency offset */ |
| 169 | #define ADJ_MAXERROR 0x0004 /* maximum time error */ |
| 170 | #define ADJ_ESTERROR 0x0008 /* estimated time error */ |
| 171 | #define ADJ_STATUS 0x0010 /* clock status */ |
| 172 | #define ADJ_TIMECONST 0x0020 /* pll time constant */ |
| 173 | #define ADJ_TICK 0x4000 /* tick value */ |
| 174 | #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ |
| 175 | |
| 176 | /* xntp 3.4 compatibility names */ |
| 177 | #define MOD_OFFSET ADJ_OFFSET |
| 178 | #define MOD_FREQUENCY ADJ_FREQUENCY |
| 179 | #define MOD_MAXERROR ADJ_MAXERROR |
| 180 | #define MOD_ESTERROR ADJ_ESTERROR |
| 181 | #define MOD_STATUS ADJ_STATUS |
| 182 | #define MOD_TIMECONST ADJ_TIMECONST |
| 183 | #define MOD_CLKB ADJ_TICK |
| 184 | #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ |
| 185 | |
| 186 | |
| 187 | /* |
| 188 | * Status codes (timex.status) |
| 189 | */ |
| 190 | #define STA_PLL 0x0001 /* enable PLL updates (rw) */ |
| 191 | #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ |
| 192 | #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ |
| 193 | #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ |
| 194 | |
| 195 | #define STA_INS 0x0010 /* insert leap (rw) */ |
| 196 | #define STA_DEL 0x0020 /* delete leap (rw) */ |
| 197 | #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ |
| 198 | #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ |
| 199 | |
| 200 | #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ |
| 201 | #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ |
| 202 | #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ |
| 203 | #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ |
| 204 | |
| 205 | #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ |
| 206 | |
| 207 | #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ |
| 208 | STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ |
| 209 | |
| 210 | /* |
| 211 | * Clock states (time_state) |
| 212 | */ |
| 213 | #define TIME_OK 0 /* clock synchronized, no leap second */ |
| 214 | #define TIME_INS 1 /* insert leap second */ |
| 215 | #define TIME_DEL 2 /* delete leap second */ |
| 216 | #define TIME_OOP 3 /* leap second in progress */ |
| 217 | #define TIME_WAIT 4 /* leap second has occurred */ |
| 218 | #define TIME_ERROR 5 /* clock not synchronized */ |
| 219 | #define TIME_BAD TIME_ERROR /* bw compat */ |
| 220 | |
| 221 | #ifdef __KERNEL__ |
| 222 | /* |
| 223 | * kernel variables |
| 224 | * Note: maximum error = NTP synch distance = dispersion + delay / 2; |
| 225 | * estimated error = NTP dispersion. |
| 226 | */ |
| 227 | extern unsigned long tick_usec; /* USER_HZ period (usec) */ |
| 228 | extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ |
| 229 | extern int tickadj; /* amount of adjustment per tick */ |
| 230 | |
| 231 | /* |
| 232 | * phase-lock loop variables |
| 233 | */ |
| 234 | extern int time_state; /* clock status */ |
| 235 | extern int time_status; /* clock synchronization status bits */ |
| 236 | extern long time_offset; /* time adjustment (us) */ |
| 237 | extern long time_constant; /* pll time constant */ |
| 238 | extern long time_tolerance; /* frequency tolerance (ppm) */ |
| 239 | extern long time_precision; /* clock precision (us) */ |
| 240 | extern long time_maxerror; /* maximum error */ |
| 241 | extern long time_esterror; /* estimated error */ |
| 242 | |
| 243 | extern long time_freq; /* frequency offset (scaled ppm) */ |
| 244 | extern long time_reftime; /* time at last adjustment (s) */ |
| 245 | |
| 246 | extern long time_adjust; /* The amount of adjtime left */ |
| 247 | extern long time_next_adjust; /* Value for time_adjust at next tick */ |
| 248 | |
| 249 | /* interface variables pps->timer interrupt */ |
| 250 | extern long pps_offset; /* pps time offset (us) */ |
| 251 | extern long pps_jitter; /* time dispersion (jitter) (us) */ |
| 252 | extern long pps_freq; /* frequency offset (scaled ppm) */ |
| 253 | extern long pps_stabil; /* frequency dispersion (scaled ppm) */ |
| 254 | extern long pps_valid; /* pps signal watchdog counter */ |
| 255 | |
| 256 | /* interface variables pps->adjtimex */ |
| 257 | extern int pps_shift; /* interval duration (s) (shift) */ |
| 258 | extern long pps_jitcnt; /* jitter limit exceeded */ |
| 259 | extern long pps_calcnt; /* calibration intervals */ |
| 260 | extern long pps_errcnt; /* calibration errors */ |
| 261 | extern long pps_stbcnt; /* stability limit exceeded */ |
| 262 | |
| 263 | #ifdef CONFIG_TIME_INTERPOLATION |
| 264 | |
| 265 | #define TIME_SOURCE_CPU 0 |
| 266 | #define TIME_SOURCE_MMIO64 1 |
| 267 | #define TIME_SOURCE_MMIO32 2 |
| 268 | #define TIME_SOURCE_FUNCTION 3 |
| 269 | |
| 270 | /* For proper operations time_interpolator clocks must run slightly slower |
| 271 | * than the standard clock since the interpolator may only correct by having |
| 272 | * time jump forward during a tick. A slower clock is usually a side effect |
| 273 | * of the integer divide of the nanoseconds in a second by the frequency. |
| 274 | * The accuracy of the division can be increased by specifying a shift. |
| 275 | * However, this may cause the clock not to be slow enough. |
| 276 | * The interpolator will self-tune the clock by slowing down if no |
| 277 | * resets occur or speeding up if the time jumps per analysis cycle |
| 278 | * become too high. |
| 279 | * |
| 280 | * Setting jitter compensates for a fluctuating timesource by comparing |
| 281 | * to the last value read from the timesource to insure that an earlier value |
| 282 | * is not returned by a later call. The price to pay |
| 283 | * for the compensation is that the timer routines are not as scalable anymore. |
| 284 | */ |
| 285 | |
| 286 | struct time_interpolator { |
| 287 | u16 source; /* time source flags */ |
| 288 | u8 shift; /* increases accuracy of multiply by shifting. */ |
| 289 | /* Note that bits may be lost if shift is set too high */ |
| 290 | u8 jitter; /* if set compensate for fluctuations */ |
| 291 | u32 nsec_per_cyc; /* set by register_time_interpolator() */ |
| 292 | void *addr; /* address of counter or function */ |
| 293 | u64 mask; /* mask the valid bits of the counter */ |
| 294 | unsigned long offset; /* nsec offset at last update of interpolator */ |
| 295 | u64 last_counter; /* counter value in units of the counter at last update */ |
| 296 | u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ |
| 297 | u64 frequency; /* frequency in counts/second */ |
| 298 | long drift; /* drift in parts-per-million (or -1) */ |
| 299 | unsigned long skips; /* skips forward */ |
| 300 | unsigned long ns_skipped; /* nanoseconds skipped */ |
| 301 | struct time_interpolator *next; |
| 302 | }; |
| 303 | |
| 304 | extern void register_time_interpolator(struct time_interpolator *); |
| 305 | extern void unregister_time_interpolator(struct time_interpolator *); |
| 306 | extern void time_interpolator_reset(void); |
| 307 | extern unsigned long time_interpolator_get_offset(void); |
| 308 | |
| 309 | #else /* !CONFIG_TIME_INTERPOLATION */ |
| 310 | |
| 311 | static inline void |
| 312 | time_interpolator_reset(void) |
| 313 | { |
| 314 | } |
| 315 | |
| 316 | #endif /* !CONFIG_TIME_INTERPOLATION */ |
| 317 | |
| 318 | #endif /* KERNEL */ |
| 319 | |
| 320 | #endif /* LINUX_TIMEX_H */ |