/contrib/ntp/kernel/sys/timex.h

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