kern_ntptime.c revision 50656
144574Sphk/*********************************************************************** 244574Sphk * * 345294Sphk * Copyright (c) David L. Mills 1993-1999 * 444574Sphk * * 544574Sphk * Permission to use, copy, modify, and distribute this software and * 644574Sphk * its documentation for any purpose and without fee is hereby * 744574Sphk * granted, provided that the above copyright notice appears in all * 844574Sphk * copies and that both the copyright notice and this permission * 944574Sphk * notice appear in supporting documentation, and that the name * 1044574Sphk * University of Delaware not be used in advertising or publicity * 1144574Sphk * pertaining to distribution of the software without specific, * 1244574Sphk * written prior permission. The University of Delaware makes no * 1344574Sphk * representations about the suitability this software for any * 1444574Sphk * purpose. It is provided "as is" without express or implied * 1544574Sphk * warranty. * 1644574Sphk * * 1744574Sphk **********************************************************************/ 182858Swollman 192858Swollman/* 2044574Sphk * Adapted from the original sources for FreeBSD and timecounters by: 2144666Sphk * Poul-Henning Kamp <phk@FreeBSD.org>. 222858Swollman * 2344574Sphk * The 32bit version of the "LP" macros seems a bit past its "sell by" 2444574Sphk * date so I have retained only the 64bit version and included it directly 2544574Sphk * in this file. 2621101Sjhay * 2744574Sphk * Only minor changes done to interface with the timecounters over in 2844574Sphk * sys/kern/kern_clock.c. Some of the comments below may be (even more) 2944574Sphk * confusing and/or plain wrong in that context. 302858Swollman */ 3132925Seivind 3244666Sphk#include "opt_ntp.h" 3344666Sphk 342858Swollman#include <sys/param.h> 352858Swollman#include <sys/systm.h> 3612221Sbde#include <sys/sysproto.h> 372858Swollman#include <sys/kernel.h> 382858Swollman#include <sys/proc.h> 3944574Sphk#include <sys/time.h> 402858Swollman#include <sys/timex.h> 4136941Sphk#include <sys/timepps.h> 422858Swollman#include <sys/sysctl.h> 432858Swollman 442858Swollman/* 4544574Sphk * Single-precision macros for 64-bit machines 4644574Sphk */ 4744574Sphktypedef long long l_fp; 4844574Sphk#define L_ADD(v, u) ((v) += (u)) 4944574Sphk#define L_SUB(v, u) ((v) -= (u)) 5044574Sphk#define L_ADDHI(v, a) ((v) += (long long)(a) << 32) 5144574Sphk#define L_NEG(v) ((v) = -(v)) 5244574Sphk#define L_RSHIFT(v, n) \ 5344574Sphk do { \ 5444574Sphk if ((v) < 0) \ 5544574Sphk (v) = -(-(v) >> (n)); \ 5644574Sphk else \ 5744574Sphk (v) = (v) >> (n); \ 5844574Sphk } while (0) 5944574Sphk#define L_MPY(v, a) ((v) *= (a)) 6044574Sphk#define L_CLR(v) ((v) = 0) 6144574Sphk#define L_ISNEG(v) ((v) < 0) 6244574Sphk#define L_LINT(v, a) ((v) = (long long)(a) << 32) 6344574Sphk#define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) 6444574Sphk 6544574Sphk/* 6644574Sphk * Generic NTP kernel interface 6732513Sphk * 6844574Sphk * These routines constitute the Network Time Protocol (NTP) interfaces 6944574Sphk * for user and daemon application programs. The ntp_gettime() routine 7044574Sphk * provides the time, maximum error (synch distance) and estimated error 7144574Sphk * (dispersion) to client user application programs. The ntp_adjtime() 7244574Sphk * routine is used by the NTP daemon to adjust the system clock to an 7344574Sphk * externally derived time. The time offset and related variables set by 7444574Sphk * this routine are used by other routines in this module to adjust the 7544574Sphk * phase and frequency of the clock discipline loop which controls the 7644574Sphk * system clock. 7732513Sphk * 7845294Sphk * When the kernel time is reckoned directly in nanoseconds (NTP_NANO 7944574Sphk * defined), the time at each tick interrupt is derived directly from 8044574Sphk * the kernel time variable. When the kernel time is reckoned in 8145294Sphk * microseconds, (NTP_NANO undefined), the time is derived from the 8245294Sphk * kernel time variable together with a variable representing the 8345294Sphk * leftover nanoseconds at the last tick interrupt. In either case, the 8445294Sphk * current nanosecond time is reckoned from these values plus an 8545294Sphk * interpolated value derived by the clock routines in another 8645294Sphk * architecture-specific module. The interpolation can use either a 8745294Sphk * dedicated counter or a processor cycle counter (PCC) implemented in 8845294Sphk * some architectures. 8932513Sphk * 9044574Sphk * Note that all routines must run at priority splclock or higher. 9144574Sphk */ 9244574Sphk 9344574Sphk/* 9444574Sphk * Phase/frequency-lock loop (PLL/FLL) definitions 9532513Sphk * 9644574Sphk * The nanosecond clock discipline uses two variable types, time 9744574Sphk * variables and frequency variables. Both types are represented as 64- 9844574Sphk * bit fixed-point quantities with the decimal point between two 32-bit 9944574Sphk * halves. On a 32-bit machine, each half is represented as a single 10044574Sphk * word and mathematical operations are done using multiple-precision 10144574Sphk * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 10244574Sphk * used. 10332513Sphk * 10444574Sphk * A time variable is a signed 64-bit fixed-point number in ns and 10544574Sphk * fraction. It represents the remaining time offset to be amortized 10644574Sphk * over succeeding tick interrupts. The maximum time offset is about 10745294Sphk * 0.5 s and the resolution is about 2.3e-10 ns. 10832513Sphk * 10944574Sphk * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 11044574Sphk * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 11144574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11244574Sphk * |s s s| ns | 11344574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11444574Sphk * | fraction | 11544574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11632513Sphk * 11744574Sphk * A frequency variable is a signed 64-bit fixed-point number in ns/s 11844574Sphk * and fraction. It represents the ns and fraction to be added to the 11944574Sphk * kernel time variable at each second. The maximum frequency offset is 12045294Sphk * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. 12132513Sphk * 12244574Sphk * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 12344574Sphk * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 12444574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 12544574Sphk * |s s s s s s s s s s s s s| ns/s | 12644574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 12744574Sphk * | fraction | 12844574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1292858Swollman */ 13032513Sphk/* 13132513Sphk * The following variables establish the state of the PLL/FLL and the 13244574Sphk * residual time and frequency offset of the local clock. 13332513Sphk */ 13444574Sphk#define SHIFT_PLL 4 /* PLL loop gain (shift) */ 13544574Sphk#define SHIFT_FLL 2 /* FLL loop gain (shift) */ 13632513Sphk 13744574Sphkstatic int time_state = TIME_OK; /* clock state */ 13844574Sphkstatic int time_status = STA_UNSYNC; /* clock status bits */ 13944574Sphkstatic long time_constant; /* poll interval (shift) (s) */ 14044574Sphkstatic long time_precision = 1; /* clock precision (ns) */ 14144574Sphkstatic long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 14244574Sphkstatic long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 14344574Sphkstatic long time_reftime; /* time at last adjustment (s) */ 14444574Sphkstatic long time_tick; /* nanoseconds per tick (ns) */ 14544574Sphkstatic l_fp time_offset; /* time offset (ns) */ 14644574Sphkstatic l_fp time_freq; /* frequency offset (ns/s) */ 14744574Sphk 1482858Swollman#ifdef PPS_SYNC 1492858Swollman/* 15044574Sphk * The following variables are used when a pulse-per-second (PPS) signal 15144574Sphk * is available and connected via a modem control lead. They establish 15244574Sphk * the engineering parameters of the clock discipline loop when 15344574Sphk * controlled by the PPS signal. 1542858Swollman */ 15544574Sphk#define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ 15650656Sphk#define PPS_FAVGDEF 7 /* default freq avg int (s) (shift) */ 15750656Sphk#define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */ 15844574Sphk#define PPS_PAVG 4 /* phase avg interval (s) (shift) */ 15944574Sphk#define PPS_VALID 120 /* PPS signal watchdog max (s) */ 16050656Sphk#define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */ 16150656Sphk#define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ 16232513Sphk 16350656Sphkstatic struct timespec pps_tf[3]; /* phase median filter */ 16444574Sphkstatic l_fp pps_freq; /* scaled frequency offset (ns/s) */ 16545294Sphkstatic long pps_fcount; /* frequency accumulator */ 16650656Sphkstatic long pps_jitter; /* nominal jitter (ns) */ 16750656Sphkstatic long pps_stabil; /* nominal stability (scaled ns/s) */ 16844574Sphkstatic long pps_lastsec; /* time at last calibration (s) */ 16944574Sphkstatic int pps_valid; /* signal watchdog counter */ 17044574Sphkstatic int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 17150656Sphkstatic int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ 17244574Sphkstatic int pps_intcnt; /* wander counter */ 17344574Sphk 17432513Sphk/* 17532513Sphk * PPS signal quality monitors 17632513Sphk */ 17744574Sphkstatic long pps_calcnt; /* calibration intervals */ 17844574Sphkstatic long pps_jitcnt; /* jitter limit exceeded */ 17944574Sphkstatic long pps_stbcnt; /* stability limit exceeded */ 18044574Sphkstatic long pps_errcnt; /* calibration errors */ 1812858Swollman#endif /* PPS_SYNC */ 18232513Sphk/* 18344574Sphk * End of phase/frequency-lock loop (PLL/FLL) definitions 18432513Sphk */ 18532513Sphk 18644574Sphkstatic void ntp_init(void); 18744574Sphkstatic void hardupdate(long offset); 18832513Sphk 18933690Sphk/* 19044574Sphk * ntp_gettime() - NTP user application interface 19133690Sphk * 19244574Sphk * See the timex.h header file for synopsis and API description. 19333690Sphk */ 19412279Sphkstatic int 19512279Sphkntp_sysctl SYSCTL_HANDLER_ARGS 1962858Swollman{ 19744574Sphk struct ntptimeval ntv; /* temporary structure */ 19844574Sphk struct timespec atv; /* nanosecond time */ 1992858Swollman 20044574Sphk nanotime(&atv); 20144574Sphk ntv.time.tv_sec = atv.tv_sec; 20244574Sphk ntv.time.tv_nsec = atv.tv_nsec; 2032858Swollman ntv.maxerror = time_maxerror; 2042858Swollman ntv.esterror = time_esterror; 2052858Swollman ntv.time_state = time_state; 2062858Swollman 2072858Swollman /* 20844574Sphk * Status word error decode. If any of these conditions occur, 20944574Sphk * an error is returned, instead of the status word. Most 21044574Sphk * applications will care only about the fact the system clock 21144574Sphk * may not be trusted, not about the details. 2122858Swollman * 2132858Swollman * Hardware or software error 2142858Swollman */ 21544574Sphk if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 2162858Swollman 2172858Swollman /* 21844574Sphk * PPS signal lost when either time or frequency synchronization 21944574Sphk * requested 2202858Swollman */ 22144574Sphk (time_status & (STA_PPSFREQ | STA_PPSTIME) && 22244574Sphk !(time_status & STA_PPSSIGNAL)) || 2232858Swollman 2242858Swollman /* 22544574Sphk * PPS jitter exceeded when time synchronization requested 2262858Swollman */ 22744574Sphk (time_status & STA_PPSTIME && 22844574Sphk time_status & STA_PPSJITTER) || 2292858Swollman 2302858Swollman /* 23144574Sphk * PPS wander exceeded or calibration error when frequency 23244574Sphk * synchronization requested 2332858Swollman */ 23444574Sphk (time_status & STA_PPSFREQ && 23544574Sphk time_status & (STA_PPSWANDER | STA_PPSERROR))) 2362858Swollman ntv.time_state = TIME_ERROR; 23712279Sphk return (sysctl_handle_opaque(oidp, &ntv, sizeof ntv, req)); 2382858Swollman} 2392858Swollman 24044574SphkSYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW, 0, ""); 24144574SphkSYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE|CTLFLAG_RD, 24212623Sphk 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval", ""); 24312279Sphk 24450656SphkSYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW, &pps_shiftmax, 0, ""); 2452858Swollman/* 2462858Swollman * ntp_adjtime() - NTP daemon application interface 24744574Sphk * 24844574Sphk * See the timex.h header file for synopsis and API description. 2492858Swollman */ 25012221Sbde#ifndef _SYS_SYSPROTO_H_ 2512858Swollmanstruct ntp_adjtime_args { 25244574Sphk struct timex *tp; 2532858Swollman}; 25412221Sbde#endif 2552858Swollman 2562858Swollmanint 25730994Sphkntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap) 2582858Swollman{ 25944574Sphk struct timex ntv; /* temporary structure */ 26045294Sphk long freq; /* frequency ns/s) */ 26144574Sphk int modes; /* mode bits from structure */ 26244574Sphk int s; /* caller priority */ 2632858Swollman int error; 2642858Swollman 2652858Swollman error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv)); 2662858Swollman if (error) 26744574Sphk return(error); 2682858Swollman 2692858Swollman /* 2702858Swollman * Update selected clock variables - only the superuser can 2712858Swollman * change anything. Note that there is no error checking here on 2722858Swollman * the assumption the superuser should know what it is doing. 2732858Swollman */ 2742858Swollman modes = ntv.modes; 27544776Sphk if (modes) 27646112Sphk error = suser(p); 27744574Sphk if (error) 27844574Sphk return (error); 2792858Swollman s = splclock(); 28044574Sphk if (modes & MOD_FREQUENCY) { 28145302Sphk freq = (ntv.freq * 1000LL) >> 16; 28245294Sphk if (freq > MAXFREQ) 28345294Sphk L_LINT(time_freq, MAXFREQ); 28445294Sphk else if (freq < -MAXFREQ) 28545294Sphk L_LINT(time_freq, -MAXFREQ); 28645294Sphk else 28745294Sphk L_LINT(time_freq, freq); 28845294Sphk 2892858Swollman#ifdef PPS_SYNC 29044574Sphk pps_freq = time_freq; 2912858Swollman#endif /* PPS_SYNC */ 29244574Sphk } 2932858Swollman if (modes & MOD_MAXERROR) 2942858Swollman time_maxerror = ntv.maxerror; 2952858Swollman if (modes & MOD_ESTERROR) 2962858Swollman time_esterror = ntv.esterror; 2972858Swollman if (modes & MOD_STATUS) { 2982858Swollman time_status &= STA_RONLY; 2992858Swollman time_status |= ntv.status & ~STA_RONLY; 3002858Swollman } 30145294Sphk if (modes & MOD_TIMECONST) { 30245294Sphk if (ntv.constant < 0) 30345294Sphk time_constant = 0; 30445294Sphk else if (ntv.constant > MAXTC) 30545294Sphk time_constant = MAXTC; 30645294Sphk else 30745294Sphk time_constant = ntv.constant; 30845294Sphk } 30950656Sphk#ifdef PPS_SYNC 31050656Sphk if (modes & MOD_PPSMAX) { 31150656Sphk if (ntv.shift < PPS_FAVG) 31250656Sphk pps_shiftmax = PPS_FAVG; 31350656Sphk else if (ntv.shift > PPS_FAVGMAX) 31450656Sphk pps_shiftmax = PPS_FAVGMAX; 31550656Sphk else 31650656Sphk pps_shiftmax = ntv.shift; 31750656Sphk } 31850656Sphk#endif /* PPS_SYNC */ 31944574Sphk if (modes & MOD_NANO) 32044574Sphk time_status |= STA_NANO; 32144574Sphk if (modes & MOD_MICRO) 32244574Sphk time_status &= ~STA_NANO; 32344574Sphk if (modes & MOD_CLKB) 32444574Sphk time_status |= STA_CLK; 32544574Sphk if (modes & MOD_CLKA) 32644574Sphk time_status &= ~STA_CLK; 32744574Sphk if (modes & MOD_OFFSET) { 32844574Sphk if (time_status & STA_NANO) 32944574Sphk hardupdate(ntv.offset); 33044574Sphk else 33144574Sphk hardupdate(ntv.offset * 1000); 33244574Sphk } 3332858Swollman 3342858Swollman /* 3352858Swollman * Retrieve all clock variables 3362858Swollman */ 33744574Sphk if (time_status & STA_NANO) 33844574Sphk ntv.offset = L_GINT(time_offset); 3392858Swollman else 34044574Sphk ntv.offset = L_GINT(time_offset) / 1000; 34145295Sphk ntv.freq = L_GINT((time_freq / 1000LL) << 16); 3422858Swollman ntv.maxerror = time_maxerror; 3432858Swollman ntv.esterror = time_esterror; 3442858Swollman ntv.status = time_status; 34545294Sphk ntv.constant = time_constant; 34644574Sphk if (time_status & STA_NANO) 34744574Sphk ntv.precision = time_precision; 34844574Sphk else 34944574Sphk ntv.precision = time_precision / 1000; 35044574Sphk ntv.tolerance = MAXFREQ * SCALE_PPM; 3512858Swollman#ifdef PPS_SYNC 3522858Swollman ntv.shift = pps_shift; 35345295Sphk ntv.ppsfreq = L_GINT((pps_freq / 1000LL) << 16); 35444574Sphk if (time_status & STA_NANO) 35544574Sphk ntv.jitter = pps_jitter; 35644574Sphk else 35744574Sphk ntv.jitter = pps_jitter / 1000; 3582858Swollman ntv.stabil = pps_stabil; 3592858Swollman ntv.calcnt = pps_calcnt; 3602858Swollman ntv.errcnt = pps_errcnt; 3612858Swollman ntv.jitcnt = pps_jitcnt; 3622858Swollman ntv.stbcnt = pps_stbcnt; 3632858Swollman#endif /* PPS_SYNC */ 36444574Sphk splx(s); 3652858Swollman 3662858Swollman error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv)); 36744574Sphk if (error) 36844574Sphk return (error); 36944574Sphk 37044574Sphk /* 37144574Sphk * Status word error decode. See comments in 37244574Sphk * ntp_gettime() routine. 37344574Sphk */ 37444574Sphk if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 37544574Sphk (time_status & (STA_PPSFREQ | STA_PPSTIME) && 37644574Sphk !(time_status & STA_PPSSIGNAL)) || 37744574Sphk (time_status & STA_PPSTIME && 37844574Sphk time_status & STA_PPSJITTER) || 37944574Sphk (time_status & STA_PPSFREQ && 38044574Sphk time_status & (STA_PPSWANDER | STA_PPSERROR))) 38145302Sphk p->p_retval[0] = TIME_ERROR; 38245302Sphk else 38345302Sphk p->p_retval[0] = time_state; 38445302Sphk return (error); 38544574Sphk} 38644574Sphk 38744574Sphk/* 38844574Sphk * second_overflow() - called after ntp_tick_adjust() 38944574Sphk * 39044574Sphk * This routine is ordinarily called immediately following the above 39144574Sphk * routine ntp_tick_adjust(). While these two routines are normally 39244574Sphk * combined, they are separated here only for the purposes of 39344574Sphk * simulation. 39444574Sphk */ 39544574Sphkvoid 39644574Sphkntp_update_second(struct timecounter *tcp) 39744574Sphk{ 39844574Sphk u_int32_t *newsec; 39944666Sphk l_fp ftemp, time_adj; /* 32/64-bit temporaries */ 40044574Sphk 40144574Sphk newsec = &tcp->tc_offset_sec; 40250656Sphk /* 40350656Sphk * On rollover of the second both the nanosecond and microsecond 40450656Sphk * clocks are updated and the state machine cranked as 40550656Sphk * necessary. The phase adjustment to be used for the next 40650656Sphk * second is calculated and the maximum error is increased by 40750656Sphk * the tolerance. 40850656Sphk */ 40944574Sphk time_maxerror += MAXFREQ / 1000; 41044574Sphk 41144574Sphk /* 41244574Sphk * Leap second processing. If in leap-insert state at 41344574Sphk * the end of the day, the system clock is set back one 41444574Sphk * second; if in leap-delete state, the system clock is 41544574Sphk * set ahead one second. The nano_time() routine or 41644574Sphk * external clock driver will insure that reported time 41744574Sphk * is always monotonic. 41844574Sphk */ 41944574Sphk switch (time_state) { 42044574Sphk 4212858Swollman /* 42244574Sphk * No warning. 4232858Swollman */ 42444574Sphk case TIME_OK: 42544574Sphk if (time_status & STA_INS) 42644574Sphk time_state = TIME_INS; 42744574Sphk else if (time_status & STA_DEL) 42844574Sphk time_state = TIME_DEL; 42944574Sphk break; 43044574Sphk 43144574Sphk /* 43244574Sphk * Insert second 23:59:60 following second 43344574Sphk * 23:59:59. 43444574Sphk */ 43544574Sphk case TIME_INS: 43644574Sphk if (!(time_status & STA_INS)) 43744574Sphk time_state = TIME_OK; 43844574Sphk else if ((*newsec) % 86400 == 0) { 43944574Sphk (*newsec)--; 44044574Sphk time_state = TIME_OOP; 44144574Sphk } 44244574Sphk break; 44344574Sphk 44444574Sphk /* 44544574Sphk * Delete second 23:59:59. 44644574Sphk */ 44744574Sphk case TIME_DEL: 44844574Sphk if (!(time_status & STA_DEL)) 44944574Sphk time_state = TIME_OK; 45044574Sphk else if (((*newsec) + 1) % 86400 == 0) { 45144574Sphk (*newsec)++; 45244574Sphk time_state = TIME_WAIT; 45344574Sphk } 45444574Sphk break; 45544574Sphk 45644574Sphk /* 45744574Sphk * Insert second in progress. 45844574Sphk */ 45944574Sphk case TIME_OOP: 46044574Sphk time_state = TIME_WAIT; 46144574Sphk break; 46244574Sphk 46344574Sphk /* 46444574Sphk * Wait for status bits to clear. 46544574Sphk */ 46644574Sphk case TIME_WAIT: 46744574Sphk if (!(time_status & (STA_INS | STA_DEL))) 46844574Sphk time_state = TIME_OK; 4692858Swollman } 47044574Sphk 47144574Sphk /* 47250656Sphk * Compute the total time adjustment for the next second 47350656Sphk * in ns. The offset is reduced by a factor depending on 47450656Sphk * whether the PPS signal is operating. Note that the 47550656Sphk * value is in effect scaled by the clock frequency, 47650656Sphk * since the adjustment is added at each tick interrupt. 47744574Sphk */ 47844574Sphk ftemp = time_offset; 47944574Sphk#ifdef PPS_SYNC 48044574Sphk if (time_status & STA_PPSTIME && time_status & 48144574Sphk STA_PPSSIGNAL) 48244574Sphk L_RSHIFT(ftemp, PPS_FAVG); 48350656Sphk else 48450656Sphk L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 48544574Sphk#else 48650656Sphk L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 48744574Sphk#endif /* PPS_SYNC */ 48844574Sphk time_adj = ftemp; 48944574Sphk L_SUB(time_offset, ftemp); 49044574Sphk L_ADD(time_adj, time_freq); 49144574Sphk tcp->tc_adjustment = time_adj; 49244574Sphk#ifdef PPS_SYNC 49344574Sphk if (pps_valid > 0) 49444574Sphk pps_valid--; 49544574Sphk else 49644574Sphk time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 49744574Sphk STA_PPSWANDER | STA_PPSERROR); 49844574Sphk#endif /* PPS_SYNC */ 4992858Swollman} 5002858Swollman 50144574Sphk/* 50244574Sphk * ntp_init() - initialize variables and structures 50344574Sphk * 50444574Sphk * This routine must be called after the kernel variables hz and tick 50544574Sphk * are set or changed and before the next tick interrupt. In this 50644574Sphk * particular implementation, these values are assumed set elsewhere in 50744574Sphk * the kernel. The design allows the clock frequency and tick interval 50844574Sphk * to be changed while the system is running. So, this routine should 50944574Sphk * probably be integrated with the code that does that. 51044574Sphk */ 51144574Sphkstatic void 51244574Sphkntp_init() 51344574Sphk{ 51444574Sphk 51544574Sphk /* 51644574Sphk * The following variable must be initialized any time the 51744574Sphk * kernel variable hz is changed. 51844574Sphk */ 51944574Sphk time_tick = NANOSECOND / hz; 52044574Sphk 52144574Sphk /* 52244574Sphk * The following variables are initialized only at startup. Only 52344574Sphk * those structures not cleared by the compiler need to be 52444574Sphk * initialized, and these only in the simulator. In the actual 52544574Sphk * kernel, any nonzero values here will quickly evaporate. 52644574Sphk */ 52744574Sphk L_CLR(time_offset); 52844574Sphk L_CLR(time_freq); 52932513Sphk#ifdef PPS_SYNC 53050656Sphk pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; 53150656Sphk pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; 53250656Sphk pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; 53344794Sphk pps_fcount = 0; 53444574Sphk L_CLR(pps_freq); 53544574Sphk#endif /* PPS_SYNC */ 53644574Sphk} 5372858Swollman 53844574SphkSYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, ntp_init, NULL) 53932513Sphk 54044574Sphk/* 54144574Sphk * hardupdate() - local clock update 54244574Sphk * 54344574Sphk * This routine is called by ntp_adjtime() to update the local clock 54444574Sphk * phase and frequency. The implementation is of an adaptive-parameter, 54544574Sphk * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 54644574Sphk * time and frequency offset estimates for each call. If the kernel PPS 54744574Sphk * discipline code is configured (PPS_SYNC), the PPS signal itself 54844574Sphk * determines the new time offset, instead of the calling argument. 54944574Sphk * Presumably, calls to ntp_adjtime() occur only when the caller 55044574Sphk * believes the local clock is valid within some bound (+-128 ms with 55144574Sphk * NTP). If the caller's time is far different than the PPS time, an 55244574Sphk * argument will ensue, and it's not clear who will lose. 55344574Sphk * 55444574Sphk * For uncompensated quartz crystal oscillators and nominal update 55544574Sphk * intervals less than 256 s, operation should be in phase-lock mode, 55644574Sphk * where the loop is disciplined to phase. For update intervals greater 55744574Sphk * than 1024 s, operation should be in frequency-lock mode, where the 55844574Sphk * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 55944574Sphk * is selected by the STA_MODE status bit. 56044574Sphk */ 56144574Sphkstatic void 56244574Sphkhardupdate(offset) 56344574Sphk long offset; /* clock offset (ns) */ 56444574Sphk{ 56544574Sphk long ltemp, mtemp; 56644574Sphk l_fp ftemp; 56732513Sphk 56844574Sphk /* 56944574Sphk * Select how the phase is to be controlled and from which 57044574Sphk * source. If the PPS signal is present and enabled to 57144574Sphk * discipline the time, the PPS offset is used; otherwise, the 57244574Sphk * argument offset is used. 57344574Sphk */ 57450656Sphk if (!(time_status & STA_PLL)) 57550656Sphk return; 57644574Sphk ltemp = offset; 57744574Sphk if (ltemp > MAXPHASE) 57844574Sphk ltemp = MAXPHASE; 57944574Sphk else if (ltemp < -MAXPHASE) 58044574Sphk ltemp = -MAXPHASE; 58144574Sphk if (!(time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)) 58244574Sphk L_LINT(time_offset, ltemp); 58332513Sphk 58444574Sphk /* 58544574Sphk * Select how the frequency is to be controlled and in which 58644574Sphk * mode (PLL or FLL). If the PPS signal is present and enabled 58744574Sphk * to discipline the frequency, the PPS frequency is used; 58844574Sphk * otherwise, the argument offset is used to compute it. 58944574Sphk */ 59044574Sphk if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 59144574Sphk time_reftime = time_second; 59244574Sphk return; 59344574Sphk } 59444574Sphk if (time_status & STA_FREQHOLD || time_reftime == 0) 59544574Sphk time_reftime = time_second; 59644574Sphk mtemp = time_second - time_reftime; 59750656Sphk L_LINT(ftemp, ltemp); 59850656Sphk L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 59950656Sphk L_MPY(ftemp, mtemp); 60050656Sphk L_ADD(time_freq, ftemp); 60150656Sphk time_status &= ~STA_MODE; 60250656Sphk if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) { 60344574Sphk L_LINT(ftemp, (ltemp << 4) / mtemp); 60444574Sphk L_RSHIFT(ftemp, SHIFT_FLL + 4); 60544574Sphk L_ADD(time_freq, ftemp); 60644574Sphk time_status |= STA_MODE; 60744574Sphk } 60844574Sphk time_reftime = time_second; 60944574Sphk if (L_GINT(time_freq) > MAXFREQ) 61044574Sphk L_LINT(time_freq, MAXFREQ); 61144574Sphk else if (L_GINT(time_freq) < -MAXFREQ) 61244574Sphk L_LINT(time_freq, -MAXFREQ); 61344574Sphk} 61444574Sphk 61544574Sphk#ifdef PPS_SYNC 61632513Sphk/* 61732513Sphk * hardpps() - discipline CPU clock oscillator to external PPS signal 61832513Sphk * 61932513Sphk * This routine is called at each PPS interrupt in order to discipline 62032513Sphk * the CPU clock oscillator to the PPS signal. It measures the PPS phase 62132513Sphk * and leaves it in a handy spot for the hardclock() routine. It 62232513Sphk * integrates successive PPS phase differences and calculates the 62332513Sphk * frequency offset. This is used in hardclock() to discipline the CPU 62444574Sphk * clock oscillator so that the intrinsic frequency error is cancelled 62544574Sphk * out. The code requires the caller to capture the time and 62644574Sphk * architecture-dependent hardware counter values in nanoseconds at the 62744574Sphk * on-time PPS signal transition. 62832513Sphk * 62944574Sphk * Note that, on some Unix systems this routine runs at an interrupt 63032513Sphk * priority level higher than the timer interrupt routine hardclock(). 63132513Sphk * Therefore, the variables used are distinct from the hardclock() 63244574Sphk * variables, except for the actual time and frequency variables, which 63344574Sphk * are determined by this routine and updated atomically. 63432513Sphk */ 63532513Sphkvoid 63644574Sphkhardpps(tsp, nsec) 63744574Sphk struct timespec *tsp; /* time at PPS */ 63844574Sphk long nsec; /* hardware counter at PPS */ 63932513Sphk{ 64044574Sphk long u_sec, u_nsec, v_nsec; /* temps */ 64144574Sphk l_fp ftemp; 64232513Sphk 64332513Sphk /* 64444574Sphk * The signal is first processed by a frequency discriminator 64544574Sphk * which rejects noise and input signals with frequencies 64644574Sphk * outside the range 1 +-MAXFREQ PPS. If two hits occur in the 64744574Sphk * same second, we ignore the later hit; if not and a hit occurs 64844574Sphk * outside the range gate, keep the later hit but do not 64944574Sphk * process it. 65032513Sphk */ 65144574Sphk time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 65244574Sphk time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 65344574Sphk pps_valid = PPS_VALID; 65444574Sphk u_sec = tsp->tv_sec; 65544574Sphk u_nsec = tsp->tv_nsec; 65644574Sphk if (u_nsec >= (NANOSECOND >> 1)) { 65744574Sphk u_nsec -= NANOSECOND; 65844574Sphk u_sec++; 65944574Sphk } 66050656Sphk v_nsec = u_nsec - pps_tf[0].tv_nsec; 66150656Sphk if (u_sec == pps_tf[0].tv_sec && v_nsec < -MAXFREQ) { 66244574Sphk return; 66344574Sphk } 66444574Sphk pps_tf[2] = pps_tf[1]; 66544574Sphk pps_tf[1] = pps_tf[0]; 66650656Sphk pps_tf[0].tv_sec = u_sec; 66750656Sphk pps_tf[0].tv_nsec = u_nsec; 66832513Sphk 66932513Sphk /* 67044574Sphk * Compute the difference between the current and previous 67144574Sphk * counter values. If the difference exceeds 0.5 s, assume it 67244574Sphk * has wrapped around, so correct 1.0 s. If the result exceeds 67344574Sphk * the tick interval, the sample point has crossed a tick 67444574Sphk * boundary during the last second, so correct the tick. Very 67544574Sphk * intricate. 67644574Sphk */ 67744666Sphk u_nsec = nsec; 67844574Sphk if (u_nsec > (NANOSECOND >> 1)) 67944574Sphk u_nsec -= NANOSECOND; 68044574Sphk else if (u_nsec < -(NANOSECOND >> 1)) 68144574Sphk u_nsec += NANOSECOND; 68244794Sphk pps_fcount += u_nsec; 68350656Sphk if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) { 68444574Sphk return; 68544574Sphk } 68644574Sphk time_status &= ~STA_PPSJITTER; 68744574Sphk 68844574Sphk /* 68944574Sphk * A three-stage median filter is used to help denoise the PPS 69032513Sphk * time. The median sample becomes the time offset estimate; the 69132513Sphk * difference between the other two samples becomes the time 69232513Sphk * dispersion (jitter) estimate. 69332513Sphk */ 69450656Sphk if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) { 69550656Sphk if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) { 69650656Sphk v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */ 69750656Sphk u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec; 69850656Sphk } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) { 69950656Sphk v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */ 70050656Sphk u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec; 70144574Sphk } else { 70250656Sphk v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */ 70350656Sphk u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec; 70444574Sphk } 70544574Sphk } else { 70650656Sphk if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) { 70750656Sphk v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */ 70850656Sphk u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec; 70950656Sphk } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) { 71050656Sphk v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */ 71150656Sphk u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec; 71244574Sphk } else { 71350656Sphk v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */ 71450656Sphk u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec; 71544574Sphk } 71644574Sphk } 71732513Sphk 71832513Sphk /* 71944574Sphk * Nominal jitter is due to PPS signal noise and interrupt 72050656Sphk * latency. If it exceeds the popcorn threshold, 72150656Sphk * the sample is discarded. otherwise, if so enabled, the time 72250656Sphk * offset is updated. We can tolerate a modest loss of data here 72350656Sphk * without degrading time accuracy. 72432513Sphk */ 72550656Sphk if (u_nsec > (pps_jitter << PPS_POPCORN)) { 72644574Sphk time_status |= STA_PPSJITTER; 72744574Sphk pps_jitcnt++; 72844574Sphk } else if (time_status & STA_PPSTIME) { 72950656Sphk L_LINT(ftemp, v_nsec); 73050656Sphk L_SUB(ftemp, time_offset); 73150656Sphk L_RSHIFT(ftemp, pps_shift); 73250656Sphk L_SUB(time_offset, ftemp); 73332513Sphk } 73444574Sphk pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 73550656Sphk u_sec = pps_tf[0].tv_sec - pps_lastsec; 73644574Sphk if (u_sec < (1 << pps_shift)) 73744574Sphk return; 73844574Sphk 73932513Sphk /* 74044574Sphk * At the end of the calibration interval the difference between 74144574Sphk * the first and last counter values becomes the scaled 74244574Sphk * frequency. It will later be divided by the length of the 74344574Sphk * interval to determine the frequency update. If the frequency 74444574Sphk * exceeds a sanity threshold, or if the actual calibration 74544574Sphk * interval is not equal to the expected length, the data are 74644574Sphk * discarded. We can tolerate a modest loss of data here without 74744574Sphk * degrading frequency ccuracy. 74832513Sphk */ 74944574Sphk pps_calcnt++; 75044794Sphk v_nsec = -pps_fcount; 75150656Sphk pps_lastsec = pps_tf[0].tv_sec; 75244794Sphk pps_fcount = 0; 75344574Sphk u_nsec = MAXFREQ << pps_shift; 75444574Sphk if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << 75544574Sphk pps_shift)) { 75644574Sphk time_status |= STA_PPSERROR; 75732513Sphk pps_errcnt++; 75832513Sphk return; 75932513Sphk } 76032513Sphk 76132513Sphk /* 76250656Sphk * Here the raw frequency offset and wander (stability) is 76350656Sphk * calculated. If the wander is less than the wander threshold 76450656Sphk * for four consecutive averaging intervals, the interval is 76550656Sphk * doubled; if it is greater than the threshold for four 76650656Sphk * consecutive intervals, the interval is halved. The scaled 76750656Sphk * frequency offset is converted to frequency offset. The 76850656Sphk * stability metric is calculated as the average of recent 76950656Sphk * frequency changes, but is used only for performance 77044574Sphk * monitoring. 77132513Sphk */ 77244574Sphk L_LINT(ftemp, v_nsec); 77344574Sphk L_RSHIFT(ftemp, pps_shift); 77444574Sphk L_SUB(ftemp, pps_freq); 77544574Sphk u_nsec = L_GINT(ftemp); 77650656Sphk if (u_nsec > PPS_MAXWANDER) { 77750656Sphk L_LINT(ftemp, PPS_MAXWANDER); 77844574Sphk pps_intcnt--; 77944574Sphk time_status |= STA_PPSWANDER; 78032513Sphk pps_stbcnt++; 78150656Sphk } else if (u_nsec < -PPS_MAXWANDER) { 78250656Sphk L_LINT(ftemp, -PPS_MAXWANDER); 78344574Sphk pps_intcnt--; 78432513Sphk time_status |= STA_PPSWANDER; 78544574Sphk pps_stbcnt++; 78644574Sphk } else { 78744574Sphk pps_intcnt++; 78832513Sphk } 78944574Sphk if (pps_intcnt >= 4) { 79044574Sphk pps_intcnt = 4; 79150656Sphk if (pps_shift < pps_shiftmax) { 79244574Sphk pps_shift++; 79344574Sphk pps_intcnt = 0; 79432513Sphk } 79544574Sphk } else if (pps_intcnt <= -4) { 79644574Sphk pps_intcnt = -4; 79744574Sphk if (pps_shift > PPS_FAVG) { 79844574Sphk pps_shift--; 79944574Sphk pps_intcnt = 0; 80044574Sphk } 80132513Sphk } 80244574Sphk if (u_nsec < 0) 80344574Sphk u_nsec = -u_nsec; 80444574Sphk pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 80532513Sphk 80632513Sphk /* 80750656Sphk * The PPS frequency is recalculated and clamped to the maximum 80850656Sphk * MAXFREQ. If enabled, the system clock frequency is updated as 80950656Sphk * well. 81032513Sphk */ 81144574Sphk L_ADD(pps_freq, ftemp); 81244574Sphk u_nsec = L_GINT(pps_freq); 81344574Sphk if (u_nsec > MAXFREQ) 81444574Sphk L_LINT(pps_freq, MAXFREQ); 81544574Sphk else if (u_nsec < -MAXFREQ) 81644574Sphk L_LINT(pps_freq, -MAXFREQ); 81744574Sphk if (time_status & STA_PPSFREQ) 81844574Sphk time_freq = pps_freq; 81932513Sphk} 82032513Sphk#endif /* PPS_SYNC */ 821