diff options
Diffstat (limited to 'kernel/time/ntp.c')
| -rw-r--r-- | kernel/time/ntp.c | 50 |
1 files changed, 44 insertions, 6 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8ccce15b4b2..77137bec2ae 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -15,6 +15,13 @@ #include <asm/div64.h> #include <asm/timex.h> +/* + * Timekeeping variables + */ +unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */ +unsigned long tick_nsec; /* ACTHZ period (nsec) */ +static u64 tick_length, tick_length_base; + /* Don't completely fail for HZ > 500. */ int tickadj = 500/HZ ? : 1; /* microsecs */ @@ -37,6 +44,36 @@ long time_reftime; /* time at last adjustment (s) */ long time_adjust; long time_next_adjust; +/** + * ntp_clear - Clears the NTP state variables + * + * Must be called while holding a write on the xtime_lock + */ +void ntp_clear(void) +{ + time_adjust = 0; /* stop active adjtime() */ + time_status |= STA_UNSYNC; + time_maxerror = NTP_PHASE_LIMIT; + time_esterror = NTP_PHASE_LIMIT; + + ntp_update_frequency(); + + tick_length = tick_length_base; +} + +#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE) +#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / (s64)CLOCK_TICK_RATE) + +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; + + do_div(tick_length_base, HZ); + + tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT; +} + /* * this routine handles the overflow of the microsecond field * @@ -151,6 +188,7 @@ void second_overflow(void) */ time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7); #endif + tick_length = tick_length_base; } /* @@ -204,14 +242,13 @@ void update_ntp_one_tick(void) */ 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 = tick_length; + ret += (u64)(adjtime_adjustment() * 1000) << TICK_LENGTH_SHIFT; ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10)); return ret; @@ -351,10 +388,11 @@ int do_adjtimex(struct timex *txc) time_freq = max(time_freq, -time_tolerance); } /* STA_PLL */ } /* txc->modes & ADJ_OFFSET */ - if (txc->modes & ADJ_TICK) { + if (txc->modes & ADJ_TICK) tick_usec = txc->tick; - tick_nsec = TICK_USEC_TO_NSEC(tick_usec); - } + + if (txc->modes & ADJ_TICK) + ntp_update_frequency(); } /* txc->modes */ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0) result = TIME_ERROR; |