kern_ntptime.c revision 44666
144574Sphk/*********************************************************************** 244574Sphk * * 344574Sphk * Copyright (c) David L. Mills 1993-1998 * 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 * 7844574Sphk * When the kernel time is reckoned directly in nanoseconds (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 8144574Sphk * microseconds, (NANO undefined), the time is derived from the kernel 8244574Sphk * time variable together with a variable representing the leftover 8344574Sphk * nanoseconds at the last tick interrupt. In either case, the current 8444574Sphk * nanosecond time is reckoned from these values plus an interpolated 8544574Sphk * value derived by the clock routines in another architecture-specific 8644574Sphk * module. The interpolation can use either a dedicated counter or a 8744574Sphk * processor cycle counter (PCC) implemented in some architectures. 8832513Sphk * 8944574Sphk * Note that all routines must run at priority splclock or higher. 9044574Sphk */ 9144574Sphk 9244574Sphk/* 9344574Sphk * Phase/frequency-lock loop (PLL/FLL) definitions 9432513Sphk * 9544574Sphk * The nanosecond clock discipline uses two variable types, time 9644574Sphk * variables and frequency variables. Both types are represented as 64- 9744574Sphk * bit fixed-point quantities with the decimal point between two 32-bit 9844574Sphk * halves. On a 32-bit machine, each half is represented as a single 9944574Sphk * word and mathematical operations are done using multiple-precision 10044574Sphk * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 10144574Sphk * used. 10232513Sphk * 10344574Sphk * A time variable is a signed 64-bit fixed-point number in ns and 10444574Sphk * fraction. It represents the remaining time offset to be amortized 10544574Sphk * over succeeding tick interrupts. The maximum time offset is about 10644574Sphk * 0.512 s and the resolution is about 2.3e-10 ns. 10732513Sphk * 10844574Sphk * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 10944574Sphk * 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 11044574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11144574Sphk * |s s s| ns | 11244574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11344574Sphk * | fraction | 11444574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 11532513Sphk * 11644574Sphk * A frequency variable is a signed 64-bit fixed-point number in ns/s 11744574Sphk * and fraction. It represents the ns and fraction to be added to the 11844574Sphk * kernel time variable at each second. The maximum frequency offset is 11944574Sphk * about +-512000 ns/s and the resolution is about 2.3e-10 ns/s. 12032513Sphk * 12144574Sphk * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 12244574Sphk * 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 12344574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 12444574Sphk * |s s s s s s s s s s s s s| ns/s | 12544574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 12644574Sphk * | fraction | 12744574Sphk * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1282858Swollman */ 12932513Sphk/* 13032513Sphk * The following variables establish the state of the PLL/FLL and the 13144574Sphk * residual time and frequency offset of the local clock. 13232513Sphk */ 13344574Sphk#define SHIFT_PLL 4 /* PLL loop gain (shift) */ 13444574Sphk#define SHIFT_FLL 2 /* FLL loop gain (shift) */ 13532513Sphk 13644574Sphkstatic int time_state = TIME_OK; /* clock state */ 13744574Sphkstatic int time_status = STA_UNSYNC; /* clock status bits */ 13844574Sphkstatic long time_constant; /* poll interval (shift) (s) */ 13944574Sphkstatic long time_precision = 1; /* clock precision (ns) */ 14044574Sphkstatic long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 14144574Sphkstatic long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 14244574Sphkstatic long time_reftime; /* time at last adjustment (s) */ 14344574Sphkstatic long time_tick; /* nanoseconds per tick (ns) */ 14444574Sphkstatic l_fp time_offset; /* time offset (ns) */ 14544574Sphkstatic l_fp time_freq; /* frequency offset (ns/s) */ 14644574Sphk 1472858Swollman#ifdef PPS_SYNC 1482858Swollman/* 14944574Sphk * The following variables are used when a pulse-per-second (PPS) signal 15044574Sphk * is available and connected via a modem control lead. They establish 15144574Sphk * the engineering parameters of the clock discipline loop when 15244574Sphk * controlled by the PPS signal. 1532858Swollman */ 15444574Sphk#define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ 15544574Sphk#define PPS_FAVGMAX 8 /* max freq avg interval (s) (shift) */ 15644574Sphk#define PPS_PAVG 4 /* phase avg interval (s) (shift) */ 15744574Sphk#define PPS_VALID 120 /* PPS signal watchdog max (s) */ 15844574Sphk#define MAXTIME 500000 /* max PPS error (jitter) (ns) */ 15944574Sphk#define MAXWANDER 500000 /* max PPS wander (ns/s/s) */ 16032513Sphk 16144574Sphkstruct ppstime { 16244574Sphk long sec; /* PPS seconds */ 16344574Sphk long nsec; /* PPS nanoseconds */ 16444574Sphk long count; /* PPS nanosecond counter */ 16544574Sphk}; 16644574Sphkstatic struct ppstime pps_tf[3]; /* phase median filter */ 16744574Sphkstatic struct ppstime pps_filt; /* phase offset */ 16844574Sphkstatic l_fp pps_freq; /* scaled frequency offset (ns/s) */ 16944574Sphkstatic long pps_offacc; /* offset accumulator */ 17044574Sphkstatic long pps_jitter; /* scaled time dispersion (ns) */ 17144574Sphkstatic long pps_stabil; /* scaled frequency dispersion (ns/s) */ 17244574Sphkstatic long pps_lastcount; /* last counter offset */ 17344574Sphkstatic long pps_lastsec; /* time at last calibration (s) */ 17444574Sphkstatic int pps_valid; /* signal watchdog counter */ 17544574Sphkstatic int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 17644574Sphkstatic int pps_intcnt; /* wander counter */ 17744574Sphkstatic int pps_offcnt; /* offset accumulator counter */ 17844574Sphk 17932513Sphk/* 18032513Sphk * PPS signal quality monitors 18132513Sphk */ 18244574Sphkstatic long pps_calcnt; /* calibration intervals */ 18344574Sphkstatic long pps_jitcnt; /* jitter limit exceeded */ 18444574Sphkstatic long pps_stbcnt; /* stability limit exceeded */ 18544574Sphkstatic long pps_errcnt; /* calibration errors */ 1862858Swollman#endif /* PPS_SYNC */ 18732513Sphk/* 18844574Sphk * End of phase/frequency-lock loop (PLL/FLL) definitions 18932513Sphk */ 19032513Sphk 19144574Sphkstatic void ntp_init(void); 19244574Sphkstatic void hardupdate(long offset); 19332513Sphk 19433690Sphk/* 19544574Sphk * ntp_gettime() - NTP user application interface 19633690Sphk * 19744574Sphk * See the timex.h header file for synopsis and API description. 19833690Sphk */ 19912279Sphkstatic int 20012279Sphkntp_sysctl SYSCTL_HANDLER_ARGS 2012858Swollman{ 20244574Sphk struct ntptimeval ntv; /* temporary structure */ 20344574Sphk struct timespec atv; /* nanosecond time */ 2042858Swollman 20544574Sphk nanotime(&atv); 20644574Sphk ntv.time.tv_sec = atv.tv_sec; 20744574Sphk ntv.time.tv_nsec = atv.tv_nsec; 2082858Swollman ntv.maxerror = time_maxerror; 2092858Swollman ntv.esterror = time_esterror; 2102858Swollman ntv.time_state = time_state; 2112858Swollman 2122858Swollman /* 21344574Sphk * Status word error decode. If any of these conditions occur, 21444574Sphk * an error is returned, instead of the status word. Most 21544574Sphk * applications will care only about the fact the system clock 21644574Sphk * may not be trusted, not about the details. 2172858Swollman * 2182858Swollman * Hardware or software error 2192858Swollman */ 22044574Sphk if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 2212858Swollman 2222858Swollman /* 22344574Sphk * PPS signal lost when either time or frequency synchronization 22444574Sphk * requested 2252858Swollman */ 22644574Sphk (time_status & (STA_PPSFREQ | STA_PPSTIME) && 22744574Sphk !(time_status & STA_PPSSIGNAL)) || 2282858Swollman 2292858Swollman /* 23044574Sphk * PPS jitter exceeded when time synchronization requested 2312858Swollman */ 23244574Sphk (time_status & STA_PPSTIME && 23344574Sphk time_status & STA_PPSJITTER) || 2342858Swollman 2352858Swollman /* 23644574Sphk * PPS wander exceeded or calibration error when frequency 23744574Sphk * synchronization requested 2382858Swollman */ 23944574Sphk (time_status & STA_PPSFREQ && 24044574Sphk time_status & (STA_PPSWANDER | STA_PPSERROR))) 2412858Swollman ntv.time_state = TIME_ERROR; 24212279Sphk return (sysctl_handle_opaque(oidp, &ntv, sizeof ntv, req)); 2432858Swollman} 2442858Swollman 24544574SphkSYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW, 0, ""); 24644574SphkSYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE|CTLFLAG_RD, 24712623Sphk 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval", ""); 24812279Sphk 24944574Sphk 2502858Swollman/* 2512858Swollman * ntp_adjtime() - NTP daemon application interface 25244574Sphk * 25344574Sphk * See the timex.h header file for synopsis and API description. 2542858Swollman */ 25512221Sbde#ifndef _SYS_SYSPROTO_H_ 2562858Swollmanstruct ntp_adjtime_args { 25744574Sphk struct timex *tp; 2582858Swollman}; 25912221Sbde#endif 2602858Swollman 2612858Swollmanint 26230994Sphkntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap) 2632858Swollman{ 26444574Sphk struct timex ntv; /* temporary structure */ 26544574Sphk int modes; /* mode bits from structure */ 26644574Sphk int s; /* caller priority */ 2672858Swollman int error; 2682858Swollman 2692858Swollman error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv)); 2702858Swollman if (error) 27144574Sphk return(error); 2722858Swollman 2732858Swollman /* 2742858Swollman * Update selected clock variables - only the superuser can 2752858Swollman * change anything. Note that there is no error checking here on 2762858Swollman * the assumption the superuser should know what it is doing. 2772858Swollman */ 2782858Swollman modes = ntv.modes; 27944574Sphk error = suser(p->p_cred->pc_ucred, &p->p_acflag); 28044574Sphk if (error) 28144574Sphk return (error); 2822858Swollman s = splclock(); 28344574Sphk if (modes & MOD_FREQUENCY) { 28444574Sphk L_LINT(time_freq, ntv.freq / SCALE_PPM); 2852858Swollman#ifdef PPS_SYNC 28644574Sphk pps_freq = time_freq; 2872858Swollman#endif /* PPS_SYNC */ 28844574Sphk } 2892858Swollman if (modes & MOD_MAXERROR) 2902858Swollman time_maxerror = ntv.maxerror; 2912858Swollman if (modes & MOD_ESTERROR) 2922858Swollman time_esterror = ntv.esterror; 2932858Swollman if (modes & MOD_STATUS) { 2942858Swollman time_status &= STA_RONLY; 2952858Swollman time_status |= ntv.status & ~STA_RONLY; 2962858Swollman } 2972858Swollman if (modes & MOD_TIMECONST) 2982858Swollman time_constant = ntv.constant; 29944574Sphk if (modes & MOD_NANO) 30044574Sphk time_status |= STA_NANO; 30144574Sphk if (modes & MOD_MICRO) 30244574Sphk time_status &= ~STA_NANO; 30344574Sphk if (modes & MOD_CLKB) 30444574Sphk time_status |= STA_CLK; 30544574Sphk if (modes & MOD_CLKA) 30644574Sphk time_status &= ~STA_CLK; 30744574Sphk if (modes & MOD_OFFSET) { 30844574Sphk if (time_status & STA_NANO) 30944574Sphk hardupdate(ntv.offset); 31044574Sphk else 31144574Sphk hardupdate(ntv.offset * 1000); 31244574Sphk } 3132858Swollman 3142858Swollman /* 3152858Swollman * Retrieve all clock variables 3162858Swollman */ 31744574Sphk if (time_status & STA_NANO) 31844574Sphk ntv.offset = L_GINT(time_offset); 3192858Swollman else 32044574Sphk ntv.offset = L_GINT(time_offset) / 1000; 32144574Sphk ntv.freq = L_GINT(time_freq) * SCALE_PPM; 3222858Swollman ntv.maxerror = time_maxerror; 3232858Swollman ntv.esterror = time_esterror; 3242858Swollman ntv.status = time_status; 32544574Sphk if (ntv.constant < 0) 32644574Sphk time_constant = 0; 32744574Sphk else if (ntv.constant > MAXTC) 32844574Sphk time_constant = MAXTC; 32944574Sphk else 33044574Sphk time_constant = ntv.constant; 33144574Sphk if (time_status & STA_NANO) 33244574Sphk ntv.precision = time_precision; 33344574Sphk else 33444574Sphk ntv.precision = time_precision / 1000; 33544574Sphk ntv.tolerance = MAXFREQ * SCALE_PPM; 3362858Swollman#ifdef PPS_SYNC 3372858Swollman ntv.shift = pps_shift; 33844574Sphk ntv.ppsfreq = L_GINT(pps_freq) * SCALE_PPM; 33944574Sphk ntv.jitter = pps_jitter; 34044574Sphk if (time_status & STA_NANO) 34144574Sphk ntv.jitter = pps_jitter; 34244574Sphk else 34344574Sphk ntv.jitter = pps_jitter / 1000; 3442858Swollman ntv.stabil = pps_stabil; 3452858Swollman ntv.calcnt = pps_calcnt; 3462858Swollman ntv.errcnt = pps_errcnt; 3472858Swollman ntv.jitcnt = pps_jitcnt; 3482858Swollman ntv.stbcnt = pps_stbcnt; 3492858Swollman#endif /* PPS_SYNC */ 35044574Sphk splx(s); 3512858Swollman 3522858Swollman error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv)); 35344574Sphk if (error) 35444574Sphk return (error); 35544574Sphk 35644574Sphk /* 35744574Sphk * Status word error decode. See comments in 35844574Sphk * ntp_gettime() routine. 35944574Sphk */ 36044574Sphk if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 36144574Sphk (time_status & (STA_PPSFREQ | STA_PPSTIME) && 36244574Sphk !(time_status & STA_PPSSIGNAL)) || 36344574Sphk (time_status & STA_PPSTIME && 36444574Sphk time_status & STA_PPSJITTER) || 36544574Sphk (time_status & STA_PPSFREQ && 36644574Sphk time_status & (STA_PPSWANDER | STA_PPSERROR))) 36744574Sphk return (TIME_ERROR); 36844574Sphk return (time_state); 36944574Sphk} 37044574Sphk 37144574Sphk/* 37244574Sphk * second_overflow() - called after ntp_tick_adjust() 37344574Sphk * 37444574Sphk * This routine is ordinarily called immediately following the above 37544574Sphk * routine ntp_tick_adjust(). While these two routines are normally 37644574Sphk * combined, they are separated here only for the purposes of 37744574Sphk * simulation. 37844574Sphk */ 37944574Sphkvoid 38044574Sphkntp_update_second(struct timecounter *tcp) 38144574Sphk{ 38244574Sphk u_int32_t *newsec; 38344666Sphk l_fp ftemp, time_adj; /* 32/64-bit temporaries */ 38444574Sphk 38544574Sphk newsec = &tcp->tc_offset_sec; 38644574Sphk time_maxerror += MAXFREQ / 1000; 38744574Sphk 38844574Sphk /* 38944574Sphk * Leap second processing. If in leap-insert state at 39044574Sphk * the end of the day, the system clock is set back one 39144574Sphk * second; if in leap-delete state, the system clock is 39244574Sphk * set ahead one second. The nano_time() routine or 39344574Sphk * external clock driver will insure that reported time 39444574Sphk * is always monotonic. 39544574Sphk */ 39644574Sphk switch (time_state) { 39744574Sphk 3982858Swollman /* 39944574Sphk * No warning. 4002858Swollman */ 40144574Sphk case TIME_OK: 40244574Sphk if (time_status & STA_INS) 40344574Sphk time_state = TIME_INS; 40444574Sphk else if (time_status & STA_DEL) 40544574Sphk time_state = TIME_DEL; 40644574Sphk break; 40744574Sphk 40844574Sphk /* 40944574Sphk * Insert second 23:59:60 following second 41044574Sphk * 23:59:59. 41144574Sphk */ 41244574Sphk case TIME_INS: 41344574Sphk if (!(time_status & STA_INS)) 41444574Sphk time_state = TIME_OK; 41544574Sphk else if ((*newsec) % 86400 == 0) { 41644574Sphk (*newsec)--; 41744574Sphk time_state = TIME_OOP; 41844574Sphk } 41944574Sphk break; 42044574Sphk 42144574Sphk /* 42244574Sphk * Delete second 23:59:59. 42344574Sphk */ 42444574Sphk case TIME_DEL: 42544574Sphk if (!(time_status & STA_DEL)) 42644574Sphk time_state = TIME_OK; 42744574Sphk else if (((*newsec) + 1) % 86400 == 0) { 42844574Sphk (*newsec)++; 42944574Sphk time_state = TIME_WAIT; 43044574Sphk } 43144574Sphk break; 43244574Sphk 43344574Sphk /* 43444574Sphk * Insert second in progress. 43544574Sphk */ 43644574Sphk case TIME_OOP: 43744574Sphk time_state = TIME_WAIT; 43844574Sphk break; 43944574Sphk 44044574Sphk /* 44144574Sphk * Wait for status bits to clear. 44244574Sphk */ 44344574Sphk case TIME_WAIT: 44444574Sphk if (!(time_status & (STA_INS | STA_DEL))) 44544574Sphk time_state = TIME_OK; 4462858Swollman } 44744574Sphk 44844574Sphk /* 44944574Sphk * Compute the total time adjustment for the next 45044574Sphk * second in ns. The offset is reduced by a factor 45144574Sphk * depending on FLL or PLL mode and whether the PPS 45244574Sphk * signal is operating. Note that the value is in effect 45344574Sphk * scaled by the clock frequency, since the adjustment 45444574Sphk * is added at each tick interrupt. 45544574Sphk */ 45644574Sphk ftemp = time_offset; 45744574Sphk#ifdef PPS_SYNC 45844574Sphk if (time_status & STA_PPSTIME && time_status & 45944574Sphk STA_PPSSIGNAL) 46044574Sphk L_RSHIFT(ftemp, PPS_FAVG); 46144574Sphk else if (time_status & STA_MODE) 46244574Sphk#else 46344574Sphk if (time_status & STA_MODE) 46444574Sphk#endif /* PPS_SYNC */ 46544574Sphk L_RSHIFT(ftemp, SHIFT_FLL); 46644574Sphk else 46744574Sphk L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 46844574Sphk time_adj = ftemp; 46944574Sphk L_SUB(time_offset, ftemp); 47044574Sphk L_ADD(time_adj, time_freq); 47144574Sphk tcp->tc_adjustment = time_adj; 47244574Sphk#ifdef PPS_SYNC 47344574Sphk if (pps_valid > 0) 47444574Sphk pps_valid--; 47544574Sphk else 47644574Sphk time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 47744574Sphk STA_PPSWANDER | STA_PPSERROR); 47844574Sphk#endif /* PPS_SYNC */ 4792858Swollman} 4802858Swollman 48144574Sphk/* 48244574Sphk * ntp_init() - initialize variables and structures 48344574Sphk * 48444574Sphk * This routine must be called after the kernel variables hz and tick 48544574Sphk * are set or changed and before the next tick interrupt. In this 48644574Sphk * particular implementation, these values are assumed set elsewhere in 48744574Sphk * the kernel. The design allows the clock frequency and tick interval 48844574Sphk * to be changed while the system is running. So, this routine should 48944574Sphk * probably be integrated with the code that does that. 49044574Sphk */ 49144574Sphkstatic void 49244574Sphkntp_init() 49344574Sphk{ 49444574Sphk 49544574Sphk /* 49644574Sphk * The following variable must be initialized any time the 49744574Sphk * kernel variable hz is changed. 49844574Sphk */ 49944574Sphk time_tick = NANOSECOND / hz; 50044574Sphk 50144574Sphk /* 50244574Sphk * The following variables are initialized only at startup. Only 50344574Sphk * those structures not cleared by the compiler need to be 50444574Sphk * initialized, and these only in the simulator. In the actual 50544574Sphk * kernel, any nonzero values here will quickly evaporate. 50644574Sphk */ 50744574Sphk L_CLR(time_offset); 50844574Sphk L_CLR(time_freq); 50932513Sphk#ifdef PPS_SYNC 51044574Sphk pps_filt.sec = pps_filt.nsec = pps_filt.count = 0; 51144574Sphk pps_tf[0] = pps_tf[1] = pps_tf[2] = pps_filt; 51244574Sphk L_CLR(pps_freq); 51344574Sphk#endif /* PPS_SYNC */ 51444574Sphk} 5152858Swollman 51644574SphkSYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, ntp_init, NULL) 51732513Sphk 51844574Sphk/* 51944574Sphk * hardupdate() - local clock update 52044574Sphk * 52144574Sphk * This routine is called by ntp_adjtime() to update the local clock 52244574Sphk * phase and frequency. The implementation is of an adaptive-parameter, 52344574Sphk * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 52444574Sphk * time and frequency offset estimates for each call. If the kernel PPS 52544574Sphk * discipline code is configured (PPS_SYNC), the PPS signal itself 52644574Sphk * determines the new time offset, instead of the calling argument. 52744574Sphk * Presumably, calls to ntp_adjtime() occur only when the caller 52844574Sphk * believes the local clock is valid within some bound (+-128 ms with 52944574Sphk * NTP). If the caller's time is far different than the PPS time, an 53044574Sphk * argument will ensue, and it's not clear who will lose. 53144574Sphk * 53244574Sphk * For uncompensated quartz crystal oscillators and nominal update 53344574Sphk * intervals less than 256 s, operation should be in phase-lock mode, 53444574Sphk * where the loop is disciplined to phase. For update intervals greater 53544574Sphk * than 1024 s, operation should be in frequency-lock mode, where the 53644574Sphk * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 53744574Sphk * is selected by the STA_MODE status bit. 53844574Sphk */ 53944574Sphkstatic void 54044574Sphkhardupdate(offset) 54144574Sphk long offset; /* clock offset (ns) */ 54244574Sphk{ 54344574Sphk long ltemp, mtemp; 54444574Sphk l_fp ftemp; 54532513Sphk 54644574Sphk /* 54744574Sphk * Select how the phase is to be controlled and from which 54844574Sphk * source. If the PPS signal is present and enabled to 54944574Sphk * discipline the time, the PPS offset is used; otherwise, the 55044574Sphk * argument offset is used. 55144574Sphk */ 55244574Sphk ltemp = offset; 55344574Sphk if (ltemp > MAXPHASE) 55444574Sphk ltemp = MAXPHASE; 55544574Sphk else if (ltemp < -MAXPHASE) 55644574Sphk ltemp = -MAXPHASE; 55744574Sphk if (!(time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)) 55844574Sphk L_LINT(time_offset, ltemp); 55932513Sphk 56044574Sphk /* 56144574Sphk * Select how the frequency is to be controlled and in which 56244574Sphk * mode (PLL or FLL). If the PPS signal is present and enabled 56344574Sphk * to discipline the frequency, the PPS frequency is used; 56444574Sphk * otherwise, the argument offset is used to compute it. 56544574Sphk */ 56644574Sphk if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 56744574Sphk time_reftime = time_second; 56844574Sphk return; 56944574Sphk } 57044574Sphk if (time_status & STA_FREQHOLD || time_reftime == 0) 57144574Sphk time_reftime = time_second; 57244574Sphk mtemp = time_second - time_reftime; 57344574Sphk if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC) 57444574Sphk ) { 57544574Sphk L_LINT(ftemp, (ltemp << 4) / mtemp); 57644574Sphk L_RSHIFT(ftemp, SHIFT_FLL + 4); 57744574Sphk L_ADD(time_freq, ftemp); 57844574Sphk time_status |= STA_MODE; 57944574Sphk } else { 58044574Sphk L_LINT(ftemp, ltemp); 58144574Sphk L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 58244574Sphk L_MPY(ftemp, mtemp); 58344574Sphk L_ADD(time_freq, ftemp); 58444574Sphk time_status &= ~STA_MODE; 58544574Sphk } 58644574Sphk time_reftime = time_second; 58744574Sphk if (L_GINT(time_freq) > MAXFREQ) 58844574Sphk L_LINT(time_freq, MAXFREQ); 58944574Sphk else if (L_GINT(time_freq) < -MAXFREQ) 59044574Sphk L_LINT(time_freq, -MAXFREQ); 59144574Sphk} 59244574Sphk 59344574Sphk#ifdef PPS_SYNC 59432513Sphk/* 59532513Sphk * hardpps() - discipline CPU clock oscillator to external PPS signal 59632513Sphk * 59732513Sphk * This routine is called at each PPS interrupt in order to discipline 59832513Sphk * the CPU clock oscillator to the PPS signal. It measures the PPS phase 59932513Sphk * and leaves it in a handy spot for the hardclock() routine. It 60032513Sphk * integrates successive PPS phase differences and calculates the 60132513Sphk * frequency offset. This is used in hardclock() to discipline the CPU 60244574Sphk * clock oscillator so that the intrinsic frequency error is cancelled 60344574Sphk * out. The code requires the caller to capture the time and 60444574Sphk * architecture-dependent hardware counter values in nanoseconds at the 60544574Sphk * on-time PPS signal transition. 60632513Sphk * 60744574Sphk * Note that, on some Unix systems this routine runs at an interrupt 60832513Sphk * priority level higher than the timer interrupt routine hardclock(). 60932513Sphk * Therefore, the variables used are distinct from the hardclock() 61044574Sphk * variables, except for the actual time and frequency variables, which 61144574Sphk * are determined by this routine and updated atomically. 61232513Sphk */ 61332513Sphkvoid 61444574Sphkhardpps(tsp, nsec) 61544574Sphk struct timespec *tsp; /* time at PPS */ 61644574Sphk long nsec; /* hardware counter at PPS */ 61732513Sphk{ 61844574Sphk long u_sec, u_nsec, v_nsec; /* temps */ 61944574Sphk l_fp ftemp; 62032513Sphk 62132513Sphk /* 62244574Sphk * The signal is first processed by a frequency discriminator 62344574Sphk * which rejects noise and input signals with frequencies 62444574Sphk * outside the range 1 +-MAXFREQ PPS. If two hits occur in the 62544574Sphk * same second, we ignore the later hit; if not and a hit occurs 62644574Sphk * outside the range gate, keep the later hit but do not 62744574Sphk * process it. 62832513Sphk */ 62944574Sphk time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 63044574Sphk time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 63144574Sphk pps_valid = PPS_VALID; 63244574Sphk u_sec = tsp->tv_sec; 63344574Sphk u_nsec = tsp->tv_nsec; 63444574Sphk if (u_nsec >= (NANOSECOND >> 1)) { 63544574Sphk u_nsec -= NANOSECOND; 63644574Sphk u_sec++; 63744574Sphk } 63844574Sphk v_nsec = u_nsec - pps_tf[0].nsec; 63944574Sphk if (u_sec == pps_tf[0].sec && v_nsec < -MAXFREQ) { 64044574Sphk return; 64144574Sphk } 64244574Sphk pps_tf[2] = pps_tf[1]; 64344574Sphk pps_tf[1] = pps_tf[0]; 64444574Sphk pps_tf[0].sec = u_sec; 64544574Sphk pps_tf[0].nsec = u_nsec; 64632513Sphk 64732513Sphk /* 64844574Sphk * Compute the difference between the current and previous 64944574Sphk * counter values. If the difference exceeds 0.5 s, assume it 65044574Sphk * has wrapped around, so correct 1.0 s. If the result exceeds 65144574Sphk * the tick interval, the sample point has crossed a tick 65244574Sphk * boundary during the last second, so correct the tick. Very 65344574Sphk * intricate. 65444574Sphk */ 65544666Sphk u_nsec = nsec; 65644574Sphk if (u_nsec > (NANOSECOND >> 1)) 65744574Sphk u_nsec -= NANOSECOND; 65844574Sphk else if (u_nsec < -(NANOSECOND >> 1)) 65944574Sphk u_nsec += NANOSECOND; 66044666Sphk#if 0 66144574Sphk if (u_nsec > (time_tick >> 1)) 66244574Sphk u_nsec -= time_tick; 66344574Sphk else if (u_nsec < -(time_tick >> 1)) 66444574Sphk u_nsec += time_tick; 66544666Sphk#endif 66644574Sphk pps_tf[0].count = pps_tf[1].count + u_nsec; 66744574Sphk if (v_nsec > MAXFREQ) { 66844574Sphk return; 66944574Sphk } 67044574Sphk time_status &= ~STA_PPSJITTER; 67144574Sphk 67244574Sphk /* 67344574Sphk * A three-stage median filter is used to help denoise the PPS 67432513Sphk * time. The median sample becomes the time offset estimate; the 67532513Sphk * difference between the other two samples becomes the time 67632513Sphk * dispersion (jitter) estimate. 67732513Sphk */ 67844574Sphk if (pps_tf[0].nsec > pps_tf[1].nsec) { 67944574Sphk if (pps_tf[1].nsec > pps_tf[2].nsec) { 68044574Sphk pps_filt = pps_tf[1]; /* 0 1 2 */ 68144574Sphk u_nsec = pps_tf[0].nsec - pps_tf[2].nsec; 68244574Sphk } else if (pps_tf[2].nsec > pps_tf[0].nsec) { 68344574Sphk pps_filt = pps_tf[0]; /* 2 0 1 */ 68444574Sphk u_nsec = pps_tf[2].nsec - pps_tf[1].nsec; 68544574Sphk } else { 68644574Sphk pps_filt = pps_tf[2]; /* 0 2 1 */ 68744574Sphk u_nsec = pps_tf[0].nsec - pps_tf[1].nsec; 68844574Sphk } 68944574Sphk } else { 69044574Sphk if (pps_tf[1].nsec < pps_tf[2].nsec) { 69144574Sphk pps_filt = pps_tf[1]; /* 2 1 0 */ 69244574Sphk u_nsec = pps_tf[2].nsec - pps_tf[0].nsec; 69344574Sphk } else if (pps_tf[2].nsec < pps_tf[0].nsec) { 69444574Sphk pps_filt = pps_tf[0]; /* 1 0 2 */ 69544574Sphk u_nsec = pps_tf[1].nsec - pps_tf[2].nsec; 69644574Sphk } else { 69744574Sphk pps_filt = pps_tf[2]; /* 1 2 0 */ 69844574Sphk u_nsec = pps_tf[1].nsec - pps_tf[0].nsec; 69944574Sphk } 70044574Sphk } 70132513Sphk 70232513Sphk /* 70344574Sphk * Nominal jitter is due to PPS signal noise and interrupt 70444574Sphk * latency. If it exceeds the jitter limit, the sample is 70544574Sphk * discarded. otherwise, if so enabled, the time offset is 70644574Sphk * updated. The offsets are accumulated over the phase averaging 70744574Sphk * interval to improve accuracy. The jitter is averaged only for 70844574Sphk * performance monitoring. We can tolerate a modest loss of data 70944574Sphk * here without degrading time accuracy. 71032513Sphk */ 71144574Sphk if (u_nsec > MAXTIME) { 71244574Sphk time_status |= STA_PPSJITTER; 71344574Sphk pps_jitcnt++; 71444574Sphk } else if (time_status & STA_PPSTIME) { 71544574Sphk pps_offacc -= pps_filt.nsec; 71644574Sphk pps_offcnt++; 71732513Sphk } 71844574Sphk if (pps_offcnt >= (1 << PPS_PAVG)) { 71944574Sphk if (time_status & STA_PPSTIME) { 72044574Sphk L_LINT(time_offset, pps_offacc); 72144574Sphk L_RSHIFT(time_offset, PPS_PAVG); 72244574Sphk } 72344574Sphk pps_offacc = 0; 72444574Sphk pps_offcnt = 0; 72532513Sphk 72644574Sphk } 72744574Sphk pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 72844574Sphk u_sec = pps_tf[0].sec - pps_lastsec; 72944574Sphk if (u_sec < (1 << pps_shift)) 73044574Sphk return; 73144574Sphk 73232513Sphk /* 73344574Sphk * At the end of the calibration interval the difference between 73444574Sphk * the first and last counter values becomes the scaled 73544574Sphk * frequency. It will later be divided by the length of the 73644574Sphk * interval to determine the frequency update. If the frequency 73744574Sphk * exceeds a sanity threshold, or if the actual calibration 73844574Sphk * interval is not equal to the expected length, the data are 73944574Sphk * discarded. We can tolerate a modest loss of data here without 74044574Sphk * degrading frequency ccuracy. 74132513Sphk */ 74244574Sphk pps_calcnt++; 74344574Sphk v_nsec = -pps_filt.count; 74444574Sphk pps_lastsec = pps_tf[0].sec; 74544574Sphk pps_tf[0].count = 0; 74644574Sphk u_nsec = MAXFREQ << pps_shift; 74744574Sphk if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << 74844574Sphk pps_shift)) { 74944574Sphk time_status |= STA_PPSERROR; 75032513Sphk pps_errcnt++; 75132513Sphk return; 75232513Sphk } 75332513Sphk 75432513Sphk /* 75544574Sphk * If the actual calibration interval is not equal to the 75644574Sphk * expected length, the data are discarded. If the wander is 75744574Sphk * less than the wander threshold for four consecutive 75844574Sphk * intervals, the interval is doubled; if it is greater than the 75944574Sphk * threshold for four consecutive intervals, the interval is 76044574Sphk * halved. The scaled frequency offset is converted to frequency 76144574Sphk * offset. The stability metric is calculated as the average of 76244574Sphk * recent frequency changes, but is used only for performance 76344574Sphk * monitoring. 76432513Sphk */ 76544574Sphk L_LINT(ftemp, v_nsec); 76644574Sphk L_RSHIFT(ftemp, pps_shift); 76744574Sphk L_SUB(ftemp, pps_freq); 76844574Sphk u_nsec = L_GINT(ftemp); 76944574Sphk if (u_nsec > MAXWANDER) { 77044574Sphk L_LINT(ftemp, MAXWANDER); 77144574Sphk pps_intcnt--; 77244574Sphk time_status |= STA_PPSWANDER; 77332513Sphk pps_stbcnt++; 77444574Sphk } else if (u_nsec < -MAXWANDER) { 77544574Sphk L_LINT(ftemp, -MAXWANDER); 77644574Sphk pps_intcnt--; 77732513Sphk time_status |= STA_PPSWANDER; 77844574Sphk pps_stbcnt++; 77944574Sphk } else { 78044574Sphk pps_intcnt++; 78132513Sphk } 78244574Sphk if (pps_intcnt >= 4) { 78344574Sphk pps_intcnt = 4; 78444574Sphk if (pps_shift < PPS_FAVGMAX) { 78544574Sphk pps_shift++; 78644574Sphk pps_intcnt = 0; 78732513Sphk } 78844574Sphk } else if (pps_intcnt <= -4) { 78944574Sphk pps_intcnt = -4; 79044574Sphk if (pps_shift > PPS_FAVG) { 79144574Sphk pps_shift--; 79244574Sphk pps_intcnt = 0; 79344574Sphk } 79432513Sphk } 79544574Sphk if (u_nsec < 0) 79644574Sphk u_nsec = -u_nsec; 79744574Sphk pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 79832513Sphk 79932513Sphk /* 80044574Sphk * The frequency offset is averaged into the PPS frequency. If 80144574Sphk * enabled, the system clock frequency is updated as well. 80232513Sphk */ 80344574Sphk L_RSHIFT(ftemp, PPS_FAVG); 80444574Sphk L_ADD(pps_freq, ftemp); 80544574Sphk u_nsec = L_GINT(pps_freq); 80644574Sphk if (u_nsec > MAXFREQ) 80744574Sphk L_LINT(pps_freq, MAXFREQ); 80844574Sphk else if (u_nsec < -MAXFREQ) 80944574Sphk L_LINT(pps_freq, -MAXFREQ); 81044574Sphk if (time_status & STA_PPSFREQ) 81144574Sphk time_freq = pps_freq; 81232513Sphk} 81332513Sphk#endif /* PPS_SYNC */ 814