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authorRoman Zippel <zippel@linux-m68k.org>2006-09-30 23:28:27 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:27 -0700
commit04b617e71e363e640e88be1e43f53fa6a3afef9f (patch)
treeb59e8e75e4671bc5e10f4fcaace85d4658d4d0f0 /kernel
parent97eebe138caaf78354b1fad233e63bafdcc4fd54 (diff)
[PATCH] ntp: convert time_freq to nsec value
This converts time_freq to a scaled nsec value and adds around 6bit of extra resolution. This pushes the time_freq to its 32bit limits so the calculatons have to be done with 64bit. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/ntp.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index af7563f5d4e2..9137b54613e0 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -66,7 +66,7 @@ void ntp_update_frequency(void)
{
tick_length_base = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) << TICK_LENGTH_SHIFT;
tick_length_base += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
- tick_length_base += ((s64)time_freq * NSEC_PER_USEC) << (TICK_LENGTH_SHIFT - SHIFT_USEC);
+ tick_length_base += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
do_div(tick_length_base, HZ);
@@ -200,6 +200,7 @@ void __attribute__ ((weak)) notify_arch_cmos_timer(void)
int do_adjtimex(struct timex *txc)
{
long ltemp, mtemp, save_adjust;
+ s64 freq_adj;
int result;
/* In order to modify anything, you gotta be super-user! */
@@ -245,7 +246,7 @@ int do_adjtimex(struct timex *txc)
result = -EINVAL;
goto leave;
}
- time_freq = txc->freq;
+ time_freq = ((s64)txc->freq * NSEC_PER_USEC) >> (SHIFT_USEC - SHIFT_NSEC);
}
if (txc->modes & ADJ_MAXERROR) {
@@ -278,14 +279,14 @@ int do_adjtimex(struct timex *txc)
time_adjust = txc->offset;
}
else if (time_status & STA_PLL) {
- ltemp = txc->offset;
+ ltemp = txc->offset * NSEC_PER_USEC;
/*
* Scale the phase adjustment and
* clamp to the operating range.
*/
- time_offset = min(ltemp, MAXPHASE);
- time_offset = max(time_offset, -MAXPHASE);
+ time_offset = min(ltemp, MAXPHASE * NSEC_PER_USEC);
+ time_offset = max(time_offset, -MAXPHASE * NSEC_PER_USEC);
/*
* Select whether the frequency is to be controlled
@@ -297,24 +298,31 @@ int do_adjtimex(struct timex *txc)
time_reftime = xtime.tv_sec;
mtemp = xtime.tv_sec - time_reftime;
time_reftime = xtime.tv_sec;
+ freq_adj = 0;
if (time_status & STA_FLL) {
if (mtemp >= MINSEC) {
- ltemp = ((time_offset << 12) / mtemp) << (SHIFT_USEC - 12);
- time_freq += shift_right(ltemp, SHIFT_KH);
+ freq_adj = (s64)time_offset << (SHIFT_NSEC - SHIFT_KH);
+ if (time_offset < 0) {
+ freq_adj = -freq_adj;
+ do_div(freq_adj, mtemp);
+ freq_adj = -freq_adj;
+ } else
+ do_div(freq_adj, mtemp);
} 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 +
+ freq_adj = (s64)ltemp * mtemp;
+ freq_adj = shift_right(freq_adj,(time_constant +
time_constant +
- SHIFT_KF - SHIFT_USEC));
+ SHIFT_KF - SHIFT_NSEC));
} else /* calibration interval too long (p. 12) */
result = TIME_ERROR;
}
- time_freq = min(time_freq, MAXFREQ);
- time_freq = max(time_freq, -MAXFREQ);
- time_offset = (time_offset * NSEC_PER_USEC / HZ) << SHIFT_UPDATE;
+ freq_adj += time_freq;
+ freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
+ time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
+ time_offset = (time_offset / HZ) << SHIFT_UPDATE;
} /* STA_PLL */
} /* txc->modes & ADJ_OFFSET */
if (txc->modes & ADJ_TICK)
@@ -330,7 +338,7 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
txc->offset = save_adjust;
else
txc->offset = shift_right(time_offset, SHIFT_UPDATE) * HZ / 1000;
- txc->freq = time_freq;
+ txc->freq = (time_freq / NSEC_PER_USEC) << (SHIFT_USEC - SHIFT_NSEC);
txc->maxerror = time_maxerror;
txc->esterror = time_esterror;
txc->status = time_status;

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