diff options
| -rw-r--r-- | include/linux/timex.h | 11 | ||||
| -rw-r--r-- | kernel/time/ntp.c | 51 |
2 files changed, 24 insertions, 38 deletions
diff --git a/include/linux/timex.h b/include/linux/timex.h index 671609ee1a3d..ac808f13fa0e 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -69,10 +69,9 @@ * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, * respectively. */ -#define SHIFT_KG 6 /* phase factor (shift) */ -#define SHIFT_KF 16 /* PLL frequency factor (shift) */ -#define SHIFT_KH 2 /* FLL frequency factor (shift) */ -#define MAXTC 6 /* maximum time constant (shift) */ +#define SHIFT_PLL 4 /* PLL frequency factor (shift) */ +#define SHIFT_FLL 2 /* FLL frequency factor (shift) */ +#define MAXTC 10 /* maximum time constant (shift) */ /* * The SHIFT_SCALE define establishes the decimal point of the time_phase @@ -97,8 +96,8 @@ #define MAXPHASE 512000L /* max phase error (us) */ #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ #define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */ -#define MINSEC 16L /* min interval between updates (s) */ -#define MAXSEC 1200L /* max interval between updates (s) */ +#define MINSEC 256 /* min interval between updates (s) */ +#define MAXSEC 2048 /* max interval between updates (s) */ #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ /* diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 9137b54613e0..1ab5e9d7fa50 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -145,18 +145,11 @@ void second_overflow(void) } /* - * 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. + * Compute the phase adjustment for the next second. The offset is + * reduced by a fixed factor times the time constant. */ tick_length = tick_length_base; - time_adj = time_offset; - if (!(time_status & STA_FLL)) - time_adj = shift_right(time_adj, SHIFT_KG + time_constant); - time_adj = min(time_adj, -((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC); - time_adj = max(time_adj, ((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC); + time_adj = shift_right(time_offset, SHIFT_PLL + time_constant); time_offset -= time_adj; tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE); @@ -200,7 +193,7 @@ void __attribute__ ((weak)) notify_arch_cmos_timer(void) int do_adjtimex(struct timex *txc) { long ltemp, mtemp, save_adjust; - s64 freq_adj; + s64 freq_adj, temp64; int result; /* In order to modify anything, you gotta be super-user! */ @@ -270,7 +263,7 @@ int do_adjtimex(struct timex *txc) result = -EINVAL; goto leave; } - time_constant = txc->constant; + time_constant = min(txc->constant + 4, (long)MAXTC); } if (txc->modes & ADJ_OFFSET) { /* values checked earlier */ @@ -298,26 +291,20 @@ 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) { - 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) { - freq_adj = (s64)ltemp * mtemp; - freq_adj = shift_right(freq_adj,(time_constant + - time_constant + - SHIFT_KF - SHIFT_NSEC)); - } else /* calibration interval too long (p. 12) */ - result = TIME_ERROR; + + freq_adj = (s64)time_offset * mtemp; + freq_adj = shift_right(freq_adj, time_constant * 2 + + (SHIFT_PLL + 2) * 2 - SHIFT_NSEC); + if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) { + temp64 = (s64)time_offset << (SHIFT_NSEC - SHIFT_FLL); + if (time_offset < 0) { + temp64 = -temp64; + do_div(temp64, mtemp); + freq_adj -= temp64; + } else { + do_div(temp64, mtemp); + freq_adj += temp64; + } } freq_adj += time_freq; freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC); |