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ntp: cleanup ntp.c
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This is mostly a style cleanup of ntp.c and extracts part of do_adjtimex as
ntp_update_offset().  Otherwise the functionality is still the same as before.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Roman Zippel authored and Linus Torvalds committed May 1, 2008
1 parent f8bd225 commit ee9851b
Showing 1 changed file with 91 additions and 82 deletions.
173 changes: 91 additions & 82 deletions kernel/time/ntp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ static u64 tick_length, tick_length_base;
/* TIME_ERROR prevents overwriting the CMOS clock */
static int time_state = TIME_OK; /* clock synchronization status */
int time_status = STA_UNSYNC; /* clock status bits */
static s64 time_offset; /* time adjustment (ns) */
static s64 time_offset; /* time adjustment (ns) */
static long time_constant = 2; /* pll time constant */
long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
Expand All @@ -57,6 +57,44 @@ static void ntp_update_frequency(void)
tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
}

static void ntp_update_offset(long offset)
{
long mtemp;
s64 freq_adj;

if (!(time_status & STA_PLL))
return;

time_offset = offset * NSEC_PER_USEC;

/*
* Scale the phase adjustment and
* clamp to the operating range.
*/
time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);

/*
* Select how the frequency is to be controlled
* and in which mode (PLL or FLL).
*/
if (time_status & STA_FREQHOLD || time_reftime == 0)
time_reftime = xtime.tv_sec;
mtemp = xtime.tv_sec - time_reftime;
time_reftime = xtime.tv_sec;

freq_adj = 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))
freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp);
freq_adj += time_freq;
freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
time_offset <<= SHIFT_UPDATE;
}

/**
* ntp_clear - Clears the NTP state variables
*
Expand Down Expand Up @@ -131,7 +169,7 @@ void second_overflow(void)
break;
case TIME_WAIT:
if (!(time_status & (STA_INS | STA_DEL)))
time_state = TIME_OK;
time_state = TIME_OK;
}

/*
Expand Down Expand Up @@ -234,8 +272,7 @@ static inline void notify_cmos_timer(void) { }
*/
int do_adjtimex(struct timex *txc)
{
long mtemp, save_adjust;
s64 freq_adj;
long save_adjust;
int result;

/* In order to modify anything, you gotta be super-user! */
Expand Down Expand Up @@ -272,94 +309,63 @@ int do_adjtimex(struct timex *txc)
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;
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) {
if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
result = -EINVAL;
goto leave;
}
time_freq = ((s64)txc->freq * NSEC_PER_USEC)
>> (SHIFT_USEC - SHIFT_NSEC);
}
time_freq = ((s64)txc->freq * NSEC_PER_USEC)
>> (SHIFT_USEC - SHIFT_NSEC);
}

if (txc->modes & ADJ_MAXERROR) {
if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
result = -EINVAL;
goto leave;

if (txc->modes & ADJ_MAXERROR) {
if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
result = -EINVAL;
goto leave;
}
time_maxerror = txc->maxerror;
}
time_maxerror = txc->maxerror;
}

if (txc->modes & ADJ_ESTERROR) {
if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
result = -EINVAL;
goto leave;
if (txc->modes & ADJ_ESTERROR) {
if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
result = -EINVAL;
goto leave;
}
time_esterror = txc->esterror;
}
time_esterror = txc->esterror;
}

if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
if (txc->constant < 0) { /* NTP v4 uses values > 6 */
result = -EINVAL;
goto leave;
if (txc->modes & ADJ_TIMECONST) {
if (txc->constant < 0) { /* NTP v4 uses values > 6 */
result = -EINVAL;
goto leave;
}
time_constant = min(txc->constant + 4, (long)MAXTC);
}
time_constant = min(txc->constant + 4, (long)MAXTC);
}

if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
/* adjtime() is independent from ntp_adjtime() */
time_adjust = txc->offset;
if (txc->modes & ADJ_OFFSET) {
if (txc->modes == ADJ_OFFSET_SINGLESHOT)
/* adjtime() is independent from ntp_adjtime() */
time_adjust = txc->offset;
else
ntp_update_offset(txc->offset);
}
else if (time_status & STA_PLL) {
time_offset = txc->offset * NSEC_PER_USEC;

/*
* Scale the phase adjustment and
* clamp to the operating range.
*/
time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);

/*
* 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;

freq_adj = 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))
freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp);
freq_adj += time_freq;
freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
time_offset <<= SHIFT_UPDATE;
} /* STA_PLL */
} /* txc->modes & ADJ_OFFSET */
if (txc->modes & ADJ_TICK)
tick_usec = txc->tick;

if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
ntp_update_frequency();
} /* txc->modes */
leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
if (txc->modes & ADJ_TICK)
tick_usec = txc->tick;

if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
ntp_update_frequency();
}
leave:
if (time_status & (STA_UNSYNC|STA_CLOCKERR))
result = TIME_ERROR;

if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
(txc->modes == ADJ_OFFSET_SS_READ))
(txc->modes == ADJ_OFFSET_SS_READ))
txc->offset = save_adjust;
else
txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
Expand All @@ -384,9 +390,12 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
txc->errcnt = 0;
txc->stbcnt = 0;
write_sequnlock_irq(&xtime_lock);

do_gettimeofday(&txc->time);

notify_cmos_timer();
return(result);

return result;
}

static int __init ntp_tick_adj_setup(char *str)
Expand Down

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