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authornordin <nordin@openbsd.org>2002-07-06 19:14:19 +0000
committernordin <nordin@openbsd.org>2002-07-06 19:14:19 +0000
commitc20ce3c5de2d9d8e10fd8a5cb890fcba8acf46de (patch)
treea3afefa3d136dbcd1faca83fccc22abf27c77b19 /sys/kern/kern_clock.c
parenttheo doesn't like it. (diff)
downloadwireguard-openbsd-c20ce3c5de2d9d8e10fd8a5cb890fcba8acf46de.tar.xz
wireguard-openbsd-c20ce3c5de2d9d8e10fd8a5cb890fcba8acf46de.zip
Remove kernel support for NTP. ok deraadt@ and tholo@
Diffstat (limited to 'sys/kern/kern_clock.c')
-rw-r--r--sys/kern/kern_clock.c801
1 files changed, 2 insertions, 799 deletions
diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index b4db87d8e4b..9683ffeea48 100644
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kern_clock.c,v 1.38 2002/07/03 21:19:08 miod Exp $ */
+/* $OpenBSD: kern_clock.c,v 1.39 2002/07/06 19:14:20 nordin Exp $ */
/* $NetBSD: kern_clock.c,v 1.34 1996/06/09 04:51:03 briggs Exp $ */
/*-
@@ -52,7 +52,6 @@
#include <sys/signalvar.h>
#include <uvm/uvm_extern.h>
#include <sys/sysctl.h>
-#include <sys/timex.h>
#include <sys/sched.h>
#include <machine/cpu.h>
@@ -85,179 +84,6 @@
* profhz/stathz for statistics. (For profiling, every tick counts.)
*/
-#ifdef NTP /* NTP phase-locked loop in kernel */
-/*
- * Phase/frequency-lock loop (PLL/FLL) definitions
- *
- * The following variables are read and set by the ntp_adjtime() system
- * call.
- *
- * time_state shows the state of the system clock, with values defined
- * in the timex.h header file.
- *
- * time_status shows the status of the system clock, with bits defined
- * in the timex.h header file.
- *
- * time_offset is used by the PLL/FLL to adjust the system time in small
- * increments.
- *
- * time_constant determines the bandwidth or "stiffness" of the PLL.
- *
- * time_tolerance determines maximum frequency error or tolerance of the
- * CPU clock oscillator and is a property of the architecture; however,
- * in principle it could change as result of the presence of external
- * discipline signals, for instance.
- *
- * time_precision is usually equal to the kernel tick variable; however,
- * in cases where a precision clock counter or external clock is
- * available, the resolution can be much less than this and depend on
- * whether the external clock is working or not.
- *
- * time_maxerror is initialized by a ntp_adjtime() call and increased by
- * the kernel once each second to reflect the maximum error bound
- * growth.
- *
- * time_esterror is set and read by the ntp_adjtime() call, but
- * otherwise not used by the kernel.
- */
-int time_state = TIME_OK; /* clock state */
-int time_status = STA_UNSYNC; /* clock status bits */
-long time_offset = 0; /* time offset (us) */
-long time_constant = 0; /* pll time constant */
-long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */
-long time_precision; /* clock precision (us) */
-long time_maxerror = MAXPHASE; /* maximum error (us) */
-long time_esterror = MAXPHASE; /* estimated error (us) */
-
-/*
- * The following variables establish the state of the PLL/FLL and the
- * residual time and frequency offset of the local clock. The scale
- * factors are defined in the timex.h header file.
- *
- * time_phase and time_freq are the phase increment and the frequency
- * increment, respectively, of the kernel time variable.
- *
- * time_freq is set via ntp_adjtime() from a value stored in a file when
- * the synchronization daemon is first started. Its value is retrieved
- * via ntp_adjtime() and written to the file about once per hour by the
- * daemon.
- *
- * time_adj is the adjustment added to the value of tick at each timer
- * interrupt and is recomputed from time_phase and time_freq at each
- * seconds rollover.
- *
- * time_reftime is the second's portion of the system time at the last
- * call to ntp_adjtime(). It is used to adjust the time_freq variable
- * and to increase the time_maxerror as the time since last update
- * increases.
- */
-long time_phase = 0; /* phase offset (scaled us) */
-long time_freq = 0; /* frequency offset (scaled ppm) */
-long time_adj = 0; /* tick adjust (scaled 1 / hz) */
-long time_reftime = 0; /* time at last adjustment (s) */
-
-#ifdef PPS_SYNC
-/*
- * The following variables are used only if the kernel PPS discipline
- * code is configured (PPS_SYNC). The scale factors are defined in the
- * timex.h header file.
- *
- * pps_time contains the time at each calibration interval, as read by
- * microtime(). pps_count counts the seconds of the calibration
- * interval, the duration of which is nominally pps_shift in powers of
- * two.
- *
- * pps_offset is the time offset produced by the time median filter
- * pps_tf[], while pps_jitter is the dispersion (jitter) measured by
- * this filter.
- *
- * pps_freq is the frequency offset produced by the frequency median
- * filter pps_ff[], while pps_stabil is the dispersion (wander) measured
- * by this filter.
- *
- * pps_usec is latched from a high resolution counter or external clock
- * at pps_time. Here we want the hardware counter contents only, not the
- * contents plus the time_tv.usec as usual.
- *
- * pps_valid counts the number of seconds since the last PPS update. It
- * is used as a watchdog timer to disable the PPS discipline should the
- * PPS signal be lost.
- *
- * pps_glitch counts the number of seconds since the beginning of an
- * offset burst more than tick/2 from current nominal offset. It is used
- * mainly to suppress error bursts due to priority conflicts between the
- * PPS interrupt and timer interrupt.
- *
- * pps_intcnt counts the calibration intervals for use in the interval-
- * adaptation algorithm. It's just too complicated for words.
- */
-struct timeval pps_time; /* kernel time at last interval */
-long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */
-long pps_offset = 0; /* pps time offset (us) */
-long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */
-long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */
-long pps_freq = 0; /* frequency offset (scaled ppm) */
-long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
-long pps_usec = 0; /* microsec counter at last interval */
-long pps_valid = PPS_VALID; /* pps signal watchdog counter */
-int pps_glitch = 0; /* pps signal glitch counter */
-int pps_count = 0; /* calibration interval counter (s) */
-int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
-int pps_intcnt = 0; /* intervals at current duration */
-
-/*
- * PPS signal quality monitors
- *
- * pps_jitcnt counts the seconds that have been discarded because the
- * jitter measured by the time median filter exceeds the limit MAXTIME
- * (100 us).
- *
- * pps_calcnt counts the frequency calibration intervals, which are
- * variable from 4 s to 256 s.
- *
- * pps_errcnt counts the calibration intervals which have been discarded
- * because the wander exceeds the limit MAXFREQ (100 ppm) or where the
- * calibration interval jitter exceeds two ticks.
- *
- * pps_stbcnt counts the calibration intervals that have been discarded
- * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
- */
-long pps_jitcnt = 0; /* jitter limit exceeded */
-long pps_calcnt = 0; /* calibration intervals */
-long pps_errcnt = 0; /* calibration errors */
-long pps_stbcnt = 0; /* stability limit exceeded */
-#endif /* PPS_SYNC */
-
-#ifdef EXT_CLOCK
-/*
- * External clock definitions
- *
- * The following definitions and declarations are used only if an
- * external clock is configured on the system.
- */
-#define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */
-
-/*
- * The clock_count variable is set to CLOCK_INTERVAL at each PPS
- * interrupt and decremented once each second.
- */
-int clock_count = 0; /* CPU clock counter */
-
-#ifdef HIGHBALL
-/*
- * The clock_offset and clock_cpu variables are used by the HIGHBALL
- * interface. The clock_offset variable defines the offset between
- * system time and the HIGBALL counters. The clock_cpu variable contains
- * the offset between the system clock and the HIGHBALL clock for use in
- * disciplining the kernel time variable.
- */
-extern struct timeval clock_offset; /* Highball clock offset */
-long clock_cpu = 0; /* CPU clock adjust */
-#endif /* HIGHBALL */
-#endif /* EXT_CLOCK */
-#endif /* NTP */
-
-
/*
* Bump a timeval by a small number of usec's.
*/
@@ -280,12 +106,7 @@ int ticks;
static int psdiv, pscnt; /* prof => stat divider */
int psratio; /* ratio: prof / stat */
int tickfix, tickfixinterval; /* used if tick not really integral */
-#ifndef NTP
static int tickfixcnt; /* accumulated fractional error */
-#else
-int fixtick; /* used by NTP for same */
-int shifthz;
-#endif
long cp_time[CPUSTATES];
@@ -335,34 +156,6 @@ initclocks()
if (profhz == 0)
profhz = i;
psratio = profhz / i;
-
-#ifdef NTP
- if (time_precision == 0)
- time_precision = tick;
-
- switch (hz) {
- case 60:
- case 64:
- shifthz = SHIFT_SCALE - 6;
- break;
- case 96:
- case 100:
- case 128:
- shifthz = SHIFT_SCALE - 7;
- break;
- case 256:
- shifthz = SHIFT_SCALE - 8;
- break;
- case 1024:
- shifthz = SHIFT_SCALE - 10;
- break;
- case 1200:
- shifthz = SHIFT_SCALE - 11;
- break;
- default:
- panic("weird hz");
- }
-#endif
}
/*
@@ -376,11 +169,6 @@ hardclock(frame)
register int delta;
extern int tickdelta;
extern long timedelta;
-#ifdef NTP
- register int time_update;
- struct timeval newtime;
- register int ltemp;
-#endif
p = curproc;
if (p) {
@@ -416,7 +204,6 @@ hardclock(frame)
ticks++;
delta = tick;
-#ifndef NTP
if (tickfix) {
tickfixcnt += tickfix;
if (tickfixcnt >= tickfixinterval) {
@@ -424,9 +211,6 @@ hardclock(frame)
tickfixcnt -= tickfixinterval;
}
}
-#else
- newtime = time;
-#endif /* !NTP */
/* Imprecise 4bsd adjtime() handling */
if (timedelta != 0) {
delta += tickdelta;
@@ -437,256 +221,9 @@ hardclock(frame)
microset();
#endif
-#ifndef NTP
- BUMPTIME(&time, delta); /* XXX Now done using NTP code below */
-#endif
+ BUMPTIME(&time, delta);
BUMPTIME(&mono_time, delta);
-#ifdef NTP
- time_update = delta;
-
- /*
- * Compute the phase adjustment. If the low-order bits
- * (time_phase) of the update overflow, bump the high-order bits
- * (time_update).
- */
- time_phase += time_adj;
- if (time_phase <= -FINEUSEC) {
- ltemp = -time_phase >> SHIFT_SCALE;
- time_phase += ltemp << SHIFT_SCALE;
- time_update -= ltemp;
- } else if (time_phase >= FINEUSEC) {
- ltemp = time_phase >> SHIFT_SCALE;
- time_phase -= ltemp << SHIFT_SCALE;
- time_update += ltemp;
- }
-
-#ifdef HIGHBALL
- /*
- * If the HIGHBALL board is installed, we need to adjust the
- * external clock offset in order to close the hardware feedback
- * loop. This will adjust the external clock phase and frequency
- * in small amounts. The additional phase noise and frequency
- * wander this causes should be minimal. We also need to
- * discipline the kernel time variable, since the PLL is used to
- * discipline the external clock. If the Highball board is not
- * present, we discipline kernel time with the PLL as usual. We
- * assume that the external clock phase adjustment (time_update)
- * and kernel phase adjustment (clock_cpu) are less than the
- * value of tick.
- */
- clock_offset.tv_usec += time_update;
- if (clock_offset.tv_usec >= 1000000) {
- clock_offset.tv_sec++;
- clock_offset.tv_usec -= 1000000;
- }
- if (clock_offset.tv_usec < 0) {
- clock_offset.tv_sec--;
- clock_offset.tv_usec += 1000000;
- }
- newtime.tv_usec += clock_cpu;
- clock_cpu = 0;
-#else
- newtime.tv_usec += time_update;
-#endif /* HIGHBALL */
-
- /*
- * On rollover of the second the phase adjustment to be used for
- * the next second is calculated. Also, the maximum error is
- * increased by the tolerance. If the PPS frequency discipline
- * code is present, the phase is increased to compensate for the
- * CPU clock oscillator frequency error.
- *
- * On a 32-bit machine and given parameters in the timex.h
- * header file, the maximum phase adjustment is +-512 ms and
- * maximum frequency offset is a tad less than) +-512 ppm. On a
- * 64-bit machine, you shouldn't need to ask.
- */
- if (newtime.tv_usec >= 1000000) {
- newtime.tv_usec -= 1000000;
- newtime.tv_sec++;
- time_maxerror += time_tolerance >> SHIFT_USEC;
-
- /*
- * Leap second processing. If in leap-insert state at
- * the end of the day, the system clock is set back one
- * second; if in leap-delete state, the system clock is
- * set ahead one second. The microtime() routine or
- * external clock driver will insure that reported time
- * is always monotonic. The ugly divides should be
- * replaced.
- */
- switch (time_state) {
- case TIME_OK:
- if (time_status & STA_INS)
- time_state = TIME_INS;
- else if (time_status & STA_DEL)
- time_state = TIME_DEL;
- break;
-
- case TIME_INS:
- if (newtime.tv_sec % 86400 == 0) {
- newtime.tv_sec--;
- time_state = TIME_OOP;
- }
- break;
-
- case TIME_DEL:
- if ((newtime.tv_sec + 1) % 86400 == 0) {
- newtime.tv_sec++;
- time_state = TIME_WAIT;
- }
- break;
-
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
-
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- break;
- }
-
- /*
- * Compute the phase adjustment for the next second. In
- * PLL mode, the offset is reduced by a fixed factor
- * times the time constant. In FLL mode the offset is
- * used directly. In either mode, the maximum phase
- * adjustment for each second is clamped so as to spread
- * the adjustment over not more than the number of
- * seconds between updates.
- */
- if (time_offset < 0) {
- ltemp = -time_offset;
- if (!(time_status & STA_FLL))
- ltemp >>= SHIFT_KG + time_constant;
- if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
- ltemp = (MAXPHASE / MINSEC) <<
- SHIFT_UPDATE;
- time_offset += ltemp;
- time_adj = -ltemp << (shifthz - SHIFT_UPDATE);
- } else if (time_offset > 0) {
- ltemp = time_offset;
- if (!(time_status & STA_FLL))
- ltemp >>= SHIFT_KG + time_constant;
- if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
- ltemp = (MAXPHASE / MINSEC) <<
- SHIFT_UPDATE;
- time_offset -= ltemp;
- time_adj = ltemp << (shifthz - SHIFT_UPDATE);
- } else
- time_adj = 0;
-
- /*
- * Compute the frequency estimate and additional phase
- * adjustment due to frequency error for the next
- * second. When the PPS signal is engaged, gnaw on the
- * watchdog counter and update the frequency computed by
- * the pll and the PPS signal.
- */
-#ifdef PPS_SYNC
- pps_valid++;
- if (pps_valid >= PPS_VALID) {
- pps_valid = PPS_VALID; /* Avoid possible overflow */
- pps_jitter = MAXTIME;
- pps_stabil = MAXFREQ;
- time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
- STA_PPSWANDER | STA_PPSERROR);
- }
- ltemp = time_freq + pps_freq;
-#else
- ltemp = time_freq;
-#endif /* PPS_SYNC */
-
- if (ltemp < 0)
- time_adj -= -ltemp >> (SHIFT_USEC - shifthz);
- else
- time_adj += ltemp >> (SHIFT_USEC - shifthz);
- time_adj += (long)fixtick << shifthz;
-
- /*
- * When the CPU clock oscillator frequency is not a
- * power of 2 in Hz, shifthz is only an approximate
- * scale factor.
- */
- switch (hz) {
- case 96:
- case 100:
- /*
- * In the following code the overall gain is increased
- * by a factor of 1.25, which results in a residual
- * error less than 3 percent.
- */
- if (time_adj < 0)
- time_adj -= -time_adj >> 2;
- else
- time_adj += time_adj >> 2;
- break;
- case 60:
- /*
- * 60 Hz m68k and vaxes have a PLL gain factor of of
- * 60/64 (15/16) of what it should be. In the following code
- * the overall gain is increased by a factor of 1.0625,
- * (17/16) which results in a residual error of just less
- * than 0.4 percent.
- */
- if (time_adj < 0)
- time_adj -= -time_adj >> 4;
- else
- time_adj += time_adj >> 4;
- break;
- }
-
-#ifdef EXT_CLOCK
- /*
- * If an external clock is present, it is necessary to
- * discipline the kernel time variable anyway, since not
- * all system components use the microtime() interface.
- * Here, the time offset between the external clock and
- * kernel time variable is computed every so often.
- */
- clock_count++;
- if (clock_count > CLOCK_INTERVAL) {
- clock_count = 0;
- microtime(&clock_ext);
- delta.tv_sec = clock_ext.tv_sec - newtime.tv_sec;
- delta.tv_usec = clock_ext.tv_usec - newtime.tv_usec;
- if (delta.tv_usec < 0)
- delta.tv_sec--;
- if (delta.tv_usec >= 500000) {
- delta.tv_usec -= 1000000;
- delta.tv_sec++;
- }
- if (delta.tv_usec < -500000) {
- delta.tv_usec += 1000000;
- delta.tv_sec--;
- }
- if (delta.tv_sec > 0 || (delta.tv_sec == 0 &&
- delta.tv_usec > MAXPHASE) ||
- delta.tv_sec < -1 || (delta.tv_sec == -1 &&
- delta.tv_usec < -MAXPHASE)) {
- newtime = clock_ext;
- delta.tv_sec = 0;
- delta.tv_usec = 0;
- }
-#ifdef HIGHBALL
- clock_cpu = delta.tv_usec;
-#else /* HIGHBALL */
- hardupdate(delta.tv_usec);
-#endif /* HIGHBALL */
- }
-#endif /* EXT_CLOCK */
- }
-
-#ifdef CPU_CLOCKUPDATE
- CPU_CLOCKUPDATE(&time, &newtime);
-#else
- time = newtime;
-#endif
-
-#endif /* NTP */
-
/*
* Update real-time timeout queue.
* Process callouts at a very low cpu priority, so we don't keep the
@@ -928,340 +465,6 @@ statclock(frame)
}
}
-
-#ifdef NTP /* NTP phase-locked loop in kernel */
-
-/*
- * hardupdate() - local clock update
- *
- * This routine is called by ntp_adjtime() to update the local clock
- * phase and frequency. The implementation is of an adaptive-parameter,
- * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
- * time and frequency offset estimates for each call. If the kernel PPS
- * discipline code is configured (PPS_SYNC), the PPS signal itself
- * determines the new time offset, instead of the calling argument.
- * Presumably, calls to ntp_adjtime() occur only when the caller
- * believes the local clock is valid within some bound (+-128 ms with
- * NTP). If the caller's time is far different than the PPS time, an
- * argument will ensue, and it's not clear who will lose.
- *
- * For uncompensated quartz crystal oscillatores and nominal update
- * intervals less than 1024 s, operation should be in phase-lock mode
- * (STA_FLL = 0), where the loop is disciplined to phase. For update
- * intervals greater than this, operation should be in frequency-lock
- * mode (STA_FLL = 1), where the loop is disciplined to frequency.
- *
- * Note: splclock() is in effect.
- */
-void
-hardupdate(offset)
- long offset;
-{
- long ltemp, mtemp;
-
- if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
- return;
- ltemp = offset;
-#ifdef PPS_SYNC
- if ((time_status & STA_PPSTIME) && (time_status & STA_PPSSIGNAL))
- ltemp = pps_offset;
-#endif /* PPS_SYNC */
-
- /*
- * Scale the phase adjustment and clamp to the operating range.
- */
- if (ltemp > MAXPHASE)
- time_offset = MAXPHASE << SHIFT_UPDATE;
- else if (ltemp < -MAXPHASE)
- time_offset = -(MAXPHASE << SHIFT_UPDATE);
- else
- time_offset = ltemp << SHIFT_UPDATE;
-
- /*
- * Select whether the frequency is to be controlled and in which
- * mode (PLL or FLL). Clamp to the operating range. Ugly
- * multiply/divide should be replaced someday.
- */
- if (time_status & STA_FREQHOLD || time_reftime == 0)
- time_reftime = time.tv_sec;
- mtemp = time.tv_sec - time_reftime;
- time_reftime = time.tv_sec;
- if (time_status & STA_FLL) {
- if (mtemp >= MINSEC) {
- ltemp = ((time_offset / mtemp) << (SHIFT_USEC -
- SHIFT_UPDATE));
- if (ltemp < 0)
- time_freq -= -ltemp >> SHIFT_KH;
- else
- time_freq += ltemp >> SHIFT_KH;
- }
- } else {
- if (mtemp < MAXSEC) {
- ltemp *= mtemp;
- if (ltemp < 0)
- time_freq -= -ltemp >> (time_constant +
- time_constant + SHIFT_KF -
- SHIFT_USEC);
- else
- time_freq += ltemp >> (time_constant +
- time_constant + SHIFT_KF -
- SHIFT_USEC);
- }
- }
- if (time_freq > time_tolerance)
- time_freq = time_tolerance;
- else if (time_freq < -time_tolerance)
- time_freq = -time_tolerance;
-}
-
-#ifdef PPS_SYNC
-/*
- * hardpps() - discipline CPU clock oscillator to external PPS signal
- *
- * This routine is called at each PPS interrupt in order to discipline
- * the CPU clock oscillator to the PPS signal. It measures the PPS phase
- * and leaves it in a handy spot for the hardclock() routine. It
- * integrates successive PPS phase differences and calculates the
- * frequency offset. This is used in hardclock() to discipline the CPU
- * clock oscillator so that intrinsic frequency error is cancelled out.
- * The code requires the caller to capture the time and hardware counter
- * value at the on-time PPS signal transition.
- *
- * Note that, on some Unix systems, this routine runs at an interrupt
- * priority level higher than the timer interrupt routine hardclock().
- * Therefore, the variables used are distinct from the hardclock()
- * variables, except for certain exceptions: The PPS frequency pps_freq
- * and phase pps_offset variables are determined by this routine and
- * updated atomically. The time_tolerance variable can be considered a
- * constant, since it is infrequently changed, and then only when the
- * PPS signal is disabled. The watchdog counter pps_valid is updated
- * once per second by hardclock() and is atomically cleared in this
- * routine.
- */
-void
-hardpps(tvp, usec)
- struct timeval *tvp; /* time at PPS */
- long usec; /* hardware counter at PPS */
-{
- long u_usec, v_usec, bigtick;
- long cal_sec, cal_usec;
-
- /*
- * An occasional glitch can be produced when the PPS interrupt
- * occurs in the hardclock() routine before the time variable is
- * updated. Here the offset is discarded when the difference
- * between it and the last one is greater than tick/2, but not
- * if the interval since the first discard exceeds 30 s.
- */
- time_status |= STA_PPSSIGNAL;
- time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
- pps_valid = 0;
- u_usec = -tvp->tv_usec;
- if (u_usec < -500000)
- u_usec += 1000000;
- v_usec = pps_offset - u_usec;
- if (v_usec < 0)
- v_usec = -v_usec;
- if (v_usec > (tick >> 1)) {
- if (pps_glitch > MAXGLITCH) {
- pps_glitch = 0;
- pps_tf[2] = u_usec;
- pps_tf[1] = u_usec;
- } else {
- pps_glitch++;
- u_usec = pps_offset;
- }
- } else
- pps_glitch = 0;
-
- /*
- * A three-stage median filter is used to help deglitch the pps
- * time. The median sample becomes the time offset estimate; the
- * difference between the other two samples becomes the time
- * dispersion (jitter) estimate.
- */
- pps_tf[2] = pps_tf[1];
- pps_tf[1] = pps_tf[0];
- pps_tf[0] = u_usec;
- if (pps_tf[0] > pps_tf[1]) {
- if (pps_tf[1] > pps_tf[2]) {
- pps_offset = pps_tf[1]; /* 0 1 2 */
- v_usec = pps_tf[0] - pps_tf[2];
- } else if (pps_tf[2] > pps_tf[0]) {
- pps_offset = pps_tf[0]; /* 2 0 1 */
- v_usec = pps_tf[2] - pps_tf[1];
- } else {
- pps_offset = pps_tf[2]; /* 0 2 1 */
- v_usec = pps_tf[0] - pps_tf[1];
- }
- } else {
- if (pps_tf[1] < pps_tf[2]) {
- pps_offset = pps_tf[1]; /* 2 1 0 */
- v_usec = pps_tf[2] - pps_tf[0];
- } else if (pps_tf[2] < pps_tf[0]) {
- pps_offset = pps_tf[0]; /* 1 0 2 */
- v_usec = pps_tf[1] - pps_tf[2];
- } else {
- pps_offset = pps_tf[2]; /* 1 2 0 */
- v_usec = pps_tf[1] - pps_tf[0];
- }
- }
- if (v_usec > MAXTIME)
- pps_jitcnt++;
- v_usec = (v_usec << PPS_AVG) - pps_jitter;
- if (v_usec < 0)
- pps_jitter -= -v_usec >> PPS_AVG;
- else
- pps_jitter += v_usec >> PPS_AVG;
- if (pps_jitter > (MAXTIME >> 1))
- time_status |= STA_PPSJITTER;
-
- /*
- * During the calibration interval adjust the starting time when
- * the tick overflows. At the end of the interval compute the
- * duration of the interval and the difference of the hardware
- * counters at the beginning and end of the interval. This code
- * is deliciously complicated by the fact valid differences may
- * exceed the value of tick when using long calibration
- * intervals and small ticks. Note that the counter can be
- * greater than tick if caught at just the wrong instant, but
- * the values returned and used here are correct.
- */
- bigtick = (long)tick << SHIFT_USEC;
- pps_usec -= pps_freq;
- if (pps_usec >= bigtick)
- pps_usec -= bigtick;
- if (pps_usec < 0)
- pps_usec += bigtick;
- pps_time.tv_sec++;
- pps_count++;
- if (pps_count < (1 << pps_shift))
- return;
- pps_count = 0;
- pps_calcnt++;
- u_usec = usec << SHIFT_USEC;
- v_usec = pps_usec - u_usec;
- if (v_usec >= bigtick >> 1)
- v_usec -= bigtick;
- if (v_usec < -(bigtick >> 1))
- v_usec += bigtick;
- if (v_usec < 0)
- v_usec = -(-v_usec >> pps_shift);
- else
- v_usec = v_usec >> pps_shift;
- pps_usec = u_usec;
- cal_sec = tvp->tv_sec;
- cal_usec = tvp->tv_usec;
- cal_sec -= pps_time.tv_sec;
- cal_usec -= pps_time.tv_usec;
- if (cal_usec < 0) {
- cal_usec += 1000000;
- cal_sec--;
- }
- pps_time = *tvp;
-
- /*
- * Check for lost interrupts, noise, excessive jitter and
- * excessive frequency error. The number of timer ticks during
- * the interval may vary +-1 tick. Add to this a margin of one
- * tick for the PPS signal jitter and maximum frequency
- * deviation. If the limits are exceeded, the calibration
- * interval is reset to the minimum and we start over.
- */
- u_usec = (long)tick << 1;
- if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec))
- || (cal_sec == 0 && cal_usec < u_usec))
- || v_usec > time_tolerance || v_usec < -time_tolerance) {
- pps_errcnt++;
- pps_shift = PPS_SHIFT;
- pps_intcnt = 0;
- time_status |= STA_PPSERROR;
- return;
- }
-
- /*
- * A three-stage median filter is used to help deglitch the pps
- * frequency. The median sample becomes the frequency offset
- * estimate; the difference between the other two samples
- * becomes the frequency dispersion (stability) estimate.
- */
- pps_ff[2] = pps_ff[1];
- pps_ff[1] = pps_ff[0];
- pps_ff[0] = v_usec;
- if (pps_ff[0] > pps_ff[1]) {
- if (pps_ff[1] > pps_ff[2]) {
- u_usec = pps_ff[1]; /* 0 1 2 */
- v_usec = pps_ff[0] - pps_ff[2];
- } else if (pps_ff[2] > pps_ff[0]) {
- u_usec = pps_ff[0]; /* 2 0 1 */
- v_usec = pps_ff[2] - pps_ff[1];
- } else {
- u_usec = pps_ff[2]; /* 0 2 1 */
- v_usec = pps_ff[0] - pps_ff[1];
- }
- } else {
- if (pps_ff[1] < pps_ff[2]) {
- u_usec = pps_ff[1]; /* 2 1 0 */
- v_usec = pps_ff[2] - pps_ff[0];
- } else if (pps_ff[2] < pps_ff[0]) {
- u_usec = pps_ff[0]; /* 1 0 2 */
- v_usec = pps_ff[1] - pps_ff[2];
- } else {
- u_usec = pps_ff[2]; /* 1 2 0 */
- v_usec = pps_ff[1] - pps_ff[0];
- }
- }
-
- /*
- * Here the frequency dispersion (stability) is updated. If it
- * is less than one-fourth the maximum (MAXFREQ), the frequency
- * offset is updated as well, but clamped to the tolerance. It
- * will be processed later by the hardclock() routine.
- */
- v_usec = (v_usec >> 1) - pps_stabil;
- if (v_usec < 0)
- pps_stabil -= -v_usec >> PPS_AVG;
- else
- pps_stabil += v_usec >> PPS_AVG;
- if (pps_stabil > MAXFREQ >> 2) {
- pps_stbcnt++;
- time_status |= STA_PPSWANDER;
- return;
- }
- if (time_status & STA_PPSFREQ) {
- if (u_usec < 0) {
- pps_freq -= -u_usec >> PPS_AVG;
- if (pps_freq < -time_tolerance)
- pps_freq = -time_tolerance;
- u_usec = -u_usec;
- } else {
- pps_freq += u_usec >> PPS_AVG;
- if (pps_freq > time_tolerance)
- pps_freq = time_tolerance;
- }
- }
-
- /*
- * Here the calibration interval is adjusted. If the maximum
- * time difference is greater than tick / 4, reduce the interval
- * by half. If this is not the case for four consecutive
- * intervals, double the interval.
- */
- if (u_usec << pps_shift > bigtick >> 2) {
- pps_intcnt = 0;
- if (pps_shift > PPS_SHIFT)
- pps_shift--;
- } else if (pps_intcnt >= 4) {
- pps_intcnt = 0;
- if (pps_shift < PPS_SHIFTMAX)
- pps_shift++;
- } else
- pps_intcnt++;
-}
-#endif /* PPS_SYNC */
-#endif /* NTP */
-
-
/*
* Return information about system clocks.
*/