Hey all,
I know I've been moving a bit slowly, but I wanted to get my current
tree out there so folks could see where I'm heading w/ the timekeeping
code now that the largest chunk of logical changes has landed.
You can find the current version (C3 against 2.6.18-rc1) of the
timekeeping tree here: http://sr71.net/~jstultz/tod/
Basically it consists of a few cleanup patches, a paranoid debug patch,
and the x86-64 and ppc conversion patches as well.
On the TODO list:
o Breakup the x86-64 patch and get it -mm bound.
o ia64 patch from Peter Keilty in the works
o I need to dig up the ARM patches that hit the list awhile back.
o Rewrite the ktime_t interfaces patch.
Anyway, here is the first of those cleanups I'd like to push soon-ish.
It just simply moves all of the NTP related code and interfaces from
kernel/timer.c and kernel/time.c into kernel/time/ntp.c. There is still
a bunch of NTP cleanups to be done to the code (Now that we have decent
interfaces we can static the global variables, make do_adjtimex
readable, etc), but this is the first step.
Roman: I know you had some larger NTP changes (getting rid of
update_ntp_one_tick() for second-interval adjustments, etc). Are they
still around?
Anyway, comments or feedback would be appreciated.
thanks
-john
include/linux/timex.h | 2
kernel/time.c | 173 ---------------------
kernel/time/Makefile | 2
kernel/time/ntp.c | 396 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/timer.c | 203 -------------------------
5 files changed, 399 insertions(+), 377 deletions(-)
linux-2.6.18-rc1_timeofday-ntp-cleanup_C3.patch
============================================
diff --git a/include/linux/timex.h b/include/linux/timex.h
index 19bb653..73b9cd2 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -308,6 +308,8 @@ time_interpolator_reset(void)
/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
extern u64 current_tick_length(void);
+extern void second_overflow(void);
+extern void update_ntp_one_tick(void);
extern int do_adjtimex(struct timex *);
#endif /* KERNEL */
diff --git a/kernel/time.c b/kernel/time.c
index 5bd4897..0e017bf 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -202,179 +202,6 @@ asmlinkage long sys_settimeofday(struct
return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
}
-/* we call this to notify the arch when the clock is being
- * controlled. If no such arch routine, do nothing.
- */
-void __attribute__ ((weak)) notify_arch_cmos_timer(void)
-{
- return;
-}
-
-/* adjtimex mainly allows reading (and writing, if superuser) of
- * kernel time-keeping variables. used by xntpd.
- */
-int do_adjtimex(struct timex *txc)
-{
- long ltemp, mtemp, save_adjust;
- int result;
-
- /* In order to modify anything, you gotta be super-user! */
- if (txc->modes && !capable(CAP_SYS_TIME))
- return -EPERM;
-
- /* Now we validate the data before disabling interrupts */
-
- if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
- /* singleshot must not be used with any other mode bits */
- if (txc->modes != ADJ_OFFSET_SINGLESHOT)
- return -EINVAL;
-
- if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
- /* adjustment Offset limited to +- .512 seconds */
- if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
- return -EINVAL;
-
- /* if the quartz is off by more than 10% something is VERY wrong ! */
- if (txc->modes & ADJ_TICK)
- if (txc->tick < 900000/USER_HZ ||
- txc->tick > 1100000/USER_HZ)
- return -EINVAL;
-
- write_seqlock_irq(&xtime_lock);
- result = time_state; /* mostly `TIME_OK' */
-
- /* Save for later - semantics of adjtime is to return old value */
- save_adjust = time_next_adjust ? time_next_adjust : time_adjust;
-
-#if 0 /* STA_CLOCKERR is never set yet */
- time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
-#endif
- /* If there are input parameters, then process them */
- if (txc->modes)
- {
- if (txc->modes & ADJ_STATUS) /* only set allowed bits */
- time_status = (txc->status & ~STA_RONLY) |
- (time_status & STA_RONLY);
-
- if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
- if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
- result = -EINVAL;
- goto leave;
- }
- time_freq = txc->freq;
- }
-
- if (txc->modes & ADJ_MAXERROR) {
- if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
- result = -EINVAL;
- goto leave;
- }
- time_maxerror = txc->maxerror;
- }
-
- if (txc->modes & ADJ_ESTERROR) {
- if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
- result = -EINVAL;
- goto leave;
- }
- time_esterror = txc->esterror;
- }
-
- if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
- if (txc->constant < 0) { /* NTP v4 uses values > 6 */
- result = -EINVAL;
- goto leave;
- }
- time_constant = txc->constant;
- }
-
- if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
- if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
- /* adjtime() is independent from ntp_adjtime() */
- if ((time_next_adjust = txc->offset) == 0)
- time_adjust = 0;
- }
- else if (time_status & STA_PLL) {
- ltemp = txc->offset;
-
- /*
- * 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 = xtime.tv_sec;
- mtemp = xtime.tv_sec - time_reftime;
- time_reftime = xtime.tv_sec;
- if (time_status & STA_FLL) {
- if (mtemp >= MINSEC) {
- ltemp = (time_offset / mtemp) << (SHIFT_USEC -
- SHIFT_UPDATE);
- time_freq += shift_right(ltemp, SHIFT_KH);
- } else /* calibration interval too short (p. 12) */
- result = TIME_ERROR;
- } else { /* PLL mode */
- if (mtemp < MAXSEC) {
- ltemp *= mtemp;
- time_freq += shift_right(ltemp,(time_constant +
- time_constant +
- SHIFT_KF - SHIFT_USEC));
- } else /* calibration interval too long (p. 12) */
- result = TIME_ERROR;
- }
- time_freq = min(time_freq, time_tolerance);
- time_freq = max(time_freq, -time_tolerance);
- } /* STA_PLL */
- } /* txc->modes & ADJ_OFFSET */
- if (txc->modes & ADJ_TICK) {
- tick_usec = txc->tick;
- tick_nsec = TICK_USEC_TO_NSEC(tick_usec);
- }
- } /* txc->modes */
-leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
- result = TIME_ERROR;
-
- if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
- txc->offset = save_adjust;
- else {
- txc->offset = shift_right(time_offset, SHIFT_UPDATE);
- }
- txc->freq = time_freq;
- txc->maxerror = time_maxerror;
- txc->esterror = time_esterror;
- txc->status = time_status;
- txc->constant = time_constant;
- txc->precision = time_precision;
- txc->tolerance = time_tolerance;
- txc->tick = tick_usec;
-
- /* PPS is not implemented, so these are zero */
- txc->ppsfreq = 0;
- txc->jitter = 0;
- txc->shift = 0;
- txc->stabil = 0;
- txc->jitcnt = 0;
- txc->calcnt = 0;
- txc->errcnt = 0;
- txc->stbcnt = 0;
- write_sequnlock_irq(&xtime_lock);
- do_gettimeofday(&txc->time);
- notify_arch_cmos_timer();
- return(result);
-}
-
asmlinkage long sys_adjtimex(struct timex __user *txc_p)
{
struct timex txc; /* Local copy of parameter */
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index e1dfd8e..61a3907 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1 +1 @@
-obj-y += clocksource.o jiffies.o
+obj-y += ntp.o clocksource.o jiffies.o
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
new file mode 100644
index 0000000..7328bdf
--- /dev/null
+++ b/kernel/time/ntp.c
@@ -0,0 +1,396 @@
+/*
+ * linux/kernel/time/ntp.c
+ *
+ * NTP state machine interfaces and logic.
+ *
+ * This code was mainly moved from kernel/timer.c and kerenl/time.c
+ * Please see those files for relavent copyright info and historical
+ * changelogs.
+ */
+
+#include <linux/mm.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+
+#include <asm/div64.h>
+#include <asm/timex.h>
+
+#ifdef CONFIG_TIME_INTERPOLATION
+void time_interpolator_update(long delta_nsec);
+#else
+#define time_interpolator_update(x)
+#endif
+
+/* Don't completely fail for HZ > 500. */
+int tickadj = 500/HZ ? : 1; /* microsecs */
+
+/*
+ * phase-lock loop variables
+ */
+/* TIME_ERROR prevents overwriting the CMOS clock */
+int time_state = TIME_OK; /* clock synchronization status */
+int time_status = STA_UNSYNC; /* clock status bits */
+long time_offset; /* time adjustment (us) */
+long time_constant = 2; /* pll time constant */
+long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
+long time_precision = 1; /* clock precision (us) */
+long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
+long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
+long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
+ /* frequency offset (scaled ppm)*/
+static long time_adj; /* tick adjust (scaled 1 / HZ) */
+long time_reftime; /* time at last adjustment (s) */
+long time_adjust;
+long time_next_adjust;
+
+/*
+ * this routine handles the overflow of the microsecond field
+ *
+ * The tricky bits of code to handle the accurate clock support
+ * were provided by Dave Mills ([email protected]) of NTP fame.
+ * They were originally developed for SUN and DEC kernels.
+ * All the kudos should go to Dave for this stuff.
+ *
+ */
+void second_overflow(void)
+{
+ long ltemp;
+
+ /* Bump the maxerror field */
+ time_maxerror += time_tolerance >> SHIFT_USEC;
+ if (time_maxerror > NTP_PHASE_LIMIT) {
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_status |= STA_UNSYNC;
+ }
+
+ /*
+ * 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 (xtime.tv_sec % 86400 == 0) {
+ xtime.tv_sec--;
+ wall_to_monotonic.tv_sec++;
+ /*
+ * The timer interpolator will make time change
+ * gradually instead of an immediate jump by one second
+ */
+ time_interpolator_update(-NSEC_PER_SEC);
+ time_state = TIME_OOP;
+ clock_was_set();
+ printk(KERN_NOTICE "Clock: inserting leap second "
+ "23:59:60 UTC\n");
+ }
+ break;
+ case TIME_DEL:
+ if ((xtime.tv_sec + 1) % 86400 == 0) {
+ xtime.tv_sec++;
+ wall_to_monotonic.tv_sec--;
+ /*
+ * Use of time interpolator for a gradual change of
+ * time
+ */
+ time_interpolator_update(NSEC_PER_SEC);
+ time_state = TIME_WAIT;
+ clock_was_set();
+ printk(KERN_NOTICE "Clock: deleting leap second "
+ "23:59:59 UTC\n");
+ }
+ break;
+ case TIME_OOP:
+ time_state = TIME_WAIT;
+ break;
+ case TIME_WAIT:
+ if (!(time_status & (STA_INS | STA_DEL)))
+ time_state = TIME_OK;
+ }
+
+ /*
+ * 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.
+ */
+ ltemp = time_offset;
+ if (!(time_status & STA_FLL))
+ ltemp = shift_right(ltemp, SHIFT_KG + time_constant);
+ ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE);
+ ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE);
+ time_offset -= ltemp;
+ time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+
+ /*
+ * Compute the frequency estimate and additional phase adjustment due
+ * to frequency error for the next second.
+ */
+ ltemp = time_freq;
+ time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
+
+#if HZ == 100
+ /*
+ * Compensate for (HZ==100) != (1 << SHIFT_HZ). Add 25% and 3.125% to
+ * get 128.125; => only 0.125% error (p. 14)
+ */
+ time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5);
+#endif
+#if HZ == 250
+ /*
+ * Compensate for (HZ==250) != (1 << SHIFT_HZ). Add 1.5625% and
+ * 0.78125% to get 255.85938; => only 0.05% error (p. 14)
+ */
+ time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
+#endif
+#if HZ == 1000
+ /*
+ * Compensate for (HZ==1000) != (1 << SHIFT_HZ). Add 1.5625% and
+ * 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
+ */
+ time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
+#endif
+}
+
+/*
+ * Returns how many microseconds we need to add to xtime this tick
+ * in doing an adjustment requested with adjtime.
+ */
+static long adjtime_adjustment(void)
+{
+ long time_adjust_step;
+
+ time_adjust_step = time_adjust;
+ if (time_adjust_step) {
+ /*
+ * We are doing an adjtime thing. Prepare time_adjust_step to
+ * be within bounds. Note that a positive time_adjust means we
+ * want the clock to run faster.
+ *
+ * Limit the amount of the step to be in the range
+ * -tickadj .. +tickadj
+ */
+ time_adjust_step = min(time_adjust_step, (long)tickadj);
+ time_adjust_step = max(time_adjust_step, (long)-tickadj);
+ }
+ return time_adjust_step;
+}
+
+/* in the NTP reference this is called "hardclock()" */
+void update_ntp_one_tick(void)
+{
+ long time_adjust_step;
+
+ time_adjust_step = adjtime_adjustment();
+ if (time_adjust_step)
+ /* Reduce by this step the amount of time left */
+ time_adjust -= time_adjust_step;
+
+ /* Changes by adjtime() do not take effect till next tick. */
+ if (time_next_adjust != 0) {
+ time_adjust = time_next_adjust;
+ time_next_adjust = 0;
+ }
+}
+
+/*
+ * Return how long ticks are at the moment, that is, how much time
+ * update_wall_time_one_tick will add to xtime next time we call it
+ * (assuming no calls to do_adjtimex in the meantime).
+ * The return value is in fixed-point nanoseconds shifted by the
+ * specified number of bits to the right of the binary point.
+ * This function has no side-effects.
+ */
+u64 current_tick_length(void)
+{
+ long delta_nsec;
+ u64 ret;
+
+ /* calculate the finest interval NTP will allow.
+ * ie: nanosecond value shifted by (SHIFT_SCALE - 10)
+ */
+ delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
+ ret = (u64)delta_nsec << TICK_LENGTH_SHIFT;
+ ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10));
+
+ return ret;
+}
+
+
+void __attribute__ ((weak)) notify_arch_cmos_timer(void)
+{
+ return;
+}
+
+/* adjtimex mainly allows reading (and writing, if superuser) of
+ * kernel time-keeping variables. used by xntpd.
+ */
+int do_adjtimex(struct timex *txc)
+{
+ long ltemp, mtemp, save_adjust;
+ int result;
+
+ /* In order to modify anything, you gotta be super-user! */
+ if (txc->modes && !capable(CAP_SYS_TIME))
+ return -EPERM;
+
+ /* Now we validate the data before disabling interrupts */
+
+ if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
+ /* singleshot must not be used with any other mode bits */
+ if (txc->modes != ADJ_OFFSET_SINGLESHOT)
+ return -EINVAL;
+
+ if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
+ /* adjustment Offset limited to +- .512 seconds */
+ if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
+ return -EINVAL;
+
+ /* if the quartz is off by more than 10% something is VERY wrong ! */
+ if (txc->modes & ADJ_TICK)
+ if (txc->tick < 900000/USER_HZ ||
+ txc->tick > 1100000/USER_HZ)
+ return -EINVAL;
+
+ write_seqlock_irq(&xtime_lock);
+ result = time_state; /* mostly `TIME_OK' */
+
+ /* Save for later - semantics of adjtime is to return old value */
+ save_adjust = time_next_adjust ? time_next_adjust : time_adjust;
+
+#if 0 /* STA_CLOCKERR is never set yet */
+ time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
+#endif
+ /* If there are input parameters, then process them */
+ if (txc->modes)
+ {
+ if (txc->modes & ADJ_STATUS) /* only set allowed bits */
+ time_status = (txc->status & ~STA_RONLY) |
+ (time_status & STA_RONLY);
+
+ if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
+ if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
+ result = -EINVAL;
+ goto leave;
+ }
+ time_freq = txc->freq;
+ }
+
+ if (txc->modes & ADJ_MAXERROR) {
+ if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
+ result = -EINVAL;
+ goto leave;
+ }
+ time_maxerror = txc->maxerror;
+ }
+
+ if (txc->modes & ADJ_ESTERROR) {
+ if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
+ result = -EINVAL;
+ goto leave;
+ }
+ time_esterror = txc->esterror;
+ }
+
+ if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
+ if (txc->constant < 0) { /* NTP v4 uses values > 6 */
+ result = -EINVAL;
+ goto leave;
+ }
+ time_constant = txc->constant;
+ }
+
+ if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
+ if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
+ /* adjtime() is independent from ntp_adjtime() */
+ if ((time_next_adjust = txc->offset) == 0)
+ time_adjust = 0;
+ }
+ else if (time_status & STA_PLL) {
+ ltemp = txc->offset;
+
+ /*
+ * 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 = xtime.tv_sec;
+ mtemp = xtime.tv_sec - time_reftime;
+ time_reftime = xtime.tv_sec;
+ if (time_status & STA_FLL) {
+ if (mtemp >= MINSEC) {
+ ltemp = (time_offset / mtemp) << (SHIFT_USEC -
+ SHIFT_UPDATE);
+ time_freq += shift_right(ltemp, SHIFT_KH);
+ } else /* calibration interval too short (p. 12) */
+ result = TIME_ERROR;
+ } else { /* PLL mode */
+ if (mtemp < MAXSEC) {
+ ltemp *= mtemp;
+ time_freq += shift_right(ltemp,(time_constant +
+ time_constant +
+ SHIFT_KF - SHIFT_USEC));
+ } else /* calibration interval too long (p. 12) */
+ result = TIME_ERROR;
+ }
+ time_freq = min(time_freq, time_tolerance);
+ time_freq = max(time_freq, -time_tolerance);
+ } /* STA_PLL */
+ } /* txc->modes & ADJ_OFFSET */
+ if (txc->modes & ADJ_TICK) {
+ tick_usec = txc->tick;
+ tick_nsec = TICK_USEC_TO_NSEC(tick_usec);
+ }
+ } /* txc->modes */
+leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
+ result = TIME_ERROR;
+
+ if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
+ txc->offset = save_adjust;
+ else {
+ txc->offset = shift_right(time_offset, SHIFT_UPDATE);
+ }
+ txc->freq = time_freq;
+ txc->maxerror = time_maxerror;
+ txc->esterror = time_esterror;
+ txc->status = time_status;
+ txc->constant = time_constant;
+ txc->precision = time_precision;
+ txc->tolerance = time_tolerance;
+ txc->tick = tick_usec;
+
+ /* PPS is not implemented, so these are zero */
+ txc->ppsfreq = 0;
+ txc->jitter = 0;
+ txc->shift = 0;
+ txc->stabil = 0;
+ txc->jitcnt = 0;
+ txc->calcnt = 0;
+ txc->errcnt = 0;
+ txc->stbcnt = 0;
+ write_sequnlock_irq(&xtime_lock);
+ do_gettimeofday(&txc->time);
+ notify_arch_cmos_timer();
+ return(result);
+}
diff --git a/kernel/timer.c b/kernel/timer.c
index 2a87430..3814053 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -581,209 +581,6 @@ struct timespec wall_to_monotonic __attr
EXPORT_SYMBOL(xtime);
-/* Don't completely fail for HZ > 500. */
-int tickadj = 500/HZ ? : 1; /* microsecs */
-
-
-/*
- * phase-lock loop variables
- */
-/* TIME_ERROR prevents overwriting the CMOS clock */
-int time_state = TIME_OK; /* clock synchronization status */
-int time_status = STA_UNSYNC; /* clock status bits */
-long time_offset; /* time adjustment (us) */
-long time_constant = 2; /* pll time constant */
-long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
-long time_precision = 1; /* clock precision (us) */
-long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
-long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
-long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
- /* frequency offset (scaled ppm)*/
-static long time_adj; /* tick adjust (scaled 1 / HZ) */
-long time_reftime; /* time at last adjustment (s) */
-long time_adjust;
-long time_next_adjust;
-
-/*
- * this routine handles the overflow of the microsecond field
- *
- * The tricky bits of code to handle the accurate clock support
- * were provided by Dave Mills ([email protected]) of NTP fame.
- * They were originally developed for SUN and DEC kernels.
- * All the kudos should go to Dave for this stuff.
- *
- */
-static void second_overflow(void)
-{
- long ltemp;
-
- /* Bump the maxerror field */
- time_maxerror += time_tolerance >> SHIFT_USEC;
- if (time_maxerror > NTP_PHASE_LIMIT) {
- time_maxerror = NTP_PHASE_LIMIT;
- time_status |= STA_UNSYNC;
- }
-
- /*
- * 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 (xtime.tv_sec % 86400 == 0) {
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
- /*
- * The timer interpolator will make time change
- * gradually instead of an immediate jump by one second
- */
- time_interpolator_update(-NSEC_PER_SEC);
- time_state = TIME_OOP;
- clock_was_set();
- printk(KERN_NOTICE "Clock: inserting leap second "
- "23:59:60 UTC\n");
- }
- break;
- case TIME_DEL:
- if ((xtime.tv_sec + 1) % 86400 == 0) {
- xtime.tv_sec++;
- wall_to_monotonic.tv_sec--;
- /*
- * Use of time interpolator for a gradual change of
- * time
- */
- time_interpolator_update(NSEC_PER_SEC);
- time_state = TIME_WAIT;
- clock_was_set();
- printk(KERN_NOTICE "Clock: deleting leap second "
- "23:59:59 UTC\n");
- }
- break;
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- }
-
- /*
- * 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.
- */
- ltemp = time_offset;
- if (!(time_status & STA_FLL))
- ltemp = shift_right(ltemp, SHIFT_KG + time_constant);
- ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE);
- ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE);
- time_offset -= ltemp;
- time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
-
- /*
- * Compute the frequency estimate and additional phase adjustment due
- * to frequency error for the next second.
- */
- ltemp = time_freq;
- time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
-
-#if HZ == 100
- /*
- * Compensate for (HZ==100) != (1 << SHIFT_HZ). Add 25% and 3.125% to
- * get 128.125; => only 0.125% error (p. 14)
- */
- time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5);
-#endif
-#if HZ == 250
- /*
- * Compensate for (HZ==250) != (1 << SHIFT_HZ). Add 1.5625% and
- * 0.78125% to get 255.85938; => only 0.05% error (p. 14)
- */
- time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
-#endif
-#if HZ == 1000
- /*
- * Compensate for (HZ==1000) != (1 << SHIFT_HZ). Add 1.5625% and
- * 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
- */
- time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
-#endif
-}
-
-/*
- * Returns how many microseconds we need to add to xtime this tick
- * in doing an adjustment requested with adjtime.
- */
-static long adjtime_adjustment(void)
-{
- long time_adjust_step;
-
- time_adjust_step = time_adjust;
- if (time_adjust_step) {
- /*
- * We are doing an adjtime thing. Prepare time_adjust_step to
- * be within bounds. Note that a positive time_adjust means we
- * want the clock to run faster.
- *
- * Limit the amount of the step to be in the range
- * -tickadj .. +tickadj
- */
- time_adjust_step = min(time_adjust_step, (long)tickadj);
- time_adjust_step = max(time_adjust_step, (long)-tickadj);
- }
- return time_adjust_step;
-}
-
-/* in the NTP reference this is called "hardclock()" */
-static void update_ntp_one_tick(void)
-{
- long time_adjust_step;
-
- time_adjust_step = adjtime_adjustment();
- if (time_adjust_step)
- /* Reduce by this step the amount of time left */
- time_adjust -= time_adjust_step;
-
- /* Changes by adjtime() do not take effect till next tick. */
- if (time_next_adjust != 0) {
- time_adjust = time_next_adjust;
- time_next_adjust = 0;
- }
-}
-
-/*
- * Return how long ticks are at the moment, that is, how much time
- * update_wall_time_one_tick will add to xtime next time we call it
- * (assuming no calls to do_adjtimex in the meantime).
- * The return value is in fixed-point nanoseconds shifted by the
- * specified number of bits to the right of the binary point.
- * This function has no side-effects.
- */
-u64 current_tick_length(void)
-{
- long delta_nsec;
- u64 ret;
-
- /* calculate the finest interval NTP will allow.
- * ie: nanosecond value shifted by (SHIFT_SCALE - 10)
- */
- delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
- ret = (u64)delta_nsec << TICK_LENGTH_SHIFT;
- ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10));
-
- return ret;
-}
/* XXX - all of this timekeeping code should be later moved to time.c */
#include <linux/clocksource.h>
-
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