[deliverable/linux.git] / kernel / time / ntp.c

/*
 * linux/kernel/time/ntp.c
 *
 * NTP state machine interfaces and logic.
 *
 * This code was mainly moved from kernel/timer.c and kernel/time.c
 * Please see those files for relevant 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>

/*
 * 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;

#define MAX_TICKADJ		500		/* microsecs */
#define MAX_TICKADJ_SCALED	(((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
				  TICK_LENGTH_SHIFT) / HZ)

/*
 * 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 (ns)		*/
long time_constant = 2;			/* pll time constant		*/
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;				/* frequency offset (scaled ppm)*/
long time_reftime;			/* time at last adjustment (s)	*/
long time_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;
	time_offset = 0;
}

#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;
	tick_length_base += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);

	do_div(tick_length_base, HZ);

	tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT;
}

/*
 * 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 (Mills@UDEL.EDU) 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 time_adj;

	/* Bump the maxerror field */
	time_maxerror += MAXFREQ >> 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. The offset is
	 * reduced by a fixed factor times the time constant.
	 */
	tick_length = tick_length_base;
	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
	time_offset -= time_adj;
	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);

	if (unlikely(time_adjust)) {
		if (time_adjust > MAX_TICKADJ) {
			time_adjust -= MAX_TICKADJ;
			tick_length += MAX_TICKADJ_SCALED;
		} else if (time_adjust < -MAX_TICKADJ) {
			time_adjust += MAX_TICKADJ;
			tick_length -= MAX_TICKADJ_SCALED;
		} else {
			time_adjust = 0;
			tick_length += (s64)(time_adjust * NSEC_PER_USEC /
					     HZ) << TICK_LENGTH_SHIFT;
		}
	}
}

/*
 * 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)
{
	return tick_length;
}


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;
	s64 freq_adj, temp64;
	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_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 = ((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;
		}
		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 = 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;
		}
		else if (time_status & STA_PLL) {
		    ltemp = txc->offset * NSEC_PER_USEC;

		    /*
		     * Scale the phase adjustment and
		     * clamp to the operating range.
		     */
		    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
		     * 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 = (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);
		    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)
		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)
		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) * HZ / 1000;
	txc->freq	   = (time_freq / NSEC_PER_USEC) << (SHIFT_USEC - SHIFT_NSEC);
	txc->maxerror	   = time_maxerror;
	txc->esterror	   = time_esterror;
	txc->status	   = time_status;
	txc->constant	   = time_constant;
	txc->precision	   = time_precision;
	txc->tolerance	   = MAXFREQ;
	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);
}
Commit	Line	Data
4c7ee8de	1	/*
	2	* linux/kernel/time/ntp.c
	3	*
	4	* NTP state machine interfaces and logic.
	5	*
	6	* This code was mainly moved from kernel/timer.c and kernel/time.c
	7	* Please see those files for relevant copyright info and historical
	8	* changelogs.
	9	*/
	10
	11	#include <linux/mm.h>
	12	#include <linux/time.h>
	13	#include <linux/timex.h>
	14
	15	#include <asm/div64.h>
	16	#include <asm/timex.h>
	17
b0ee7556 RZ	18	/*
	19	* Timekeeping variables
	20	*/
	21	unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
	22	unsigned long tick_nsec; /* ACTHZ period (nsec) */
	23	static u64 tick_length, tick_length_base;
	24
8f807f8d RZ	25	#define MAX_TICKADJ 500 /* microsecs */
	26	#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
	27	TICK_LENGTH_SHIFT) / HZ)
4c7ee8de	28
	29	/*
	30	* phase-lock loop variables
	31	*/
	32	/* TIME_ERROR prevents overwriting the CMOS clock */
	33	int time_state = TIME_OK; /* clock synchronization status */
	34	int time_status = STA_UNSYNC; /* clock status bits */
3d3675cc	35	long time_offset; /* time adjustment (ns) */
4c7ee8de	36	long time_constant = 2; /* pll time constant */
4c7ee8de	37	long time_precision = 1; /* clock precision (us) */
	38	long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
	39	long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
dc6a43e4	40	long time_freq; /* frequency offset (scaled ppm)*/
4c7ee8de	41	long time_reftime; /* time at last adjustment (s) */
4c7ee8de	42	long time_adjust;
4c7ee8de	43
b0ee7556 RZ	44	/**
	45	* ntp_clear - Clears the NTP state variables
	46	*
	47	* Must be called while holding a write on the xtime_lock
	48	*/
	49	void ntp_clear(void)
	50	{
	51	time_adjust = 0; /* stop active adjtime() */
	52	time_status \|= STA_UNSYNC;
	53	time_maxerror = NTP_PHASE_LIMIT;
	54	time_esterror = NTP_PHASE_LIMIT;
	55
	56	ntp_update_frequency();
	57
	58	tick_length = tick_length_base;
3d3675cc	59	time_offset = 0;
b0ee7556 RZ	60	}
	61
	62	#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE)
	63	#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / (s64)CLOCK_TICK_RATE)
	64
	65	void ntp_update_frequency(void)
	66	{
	67	tick_length_base = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) << TICK_LENGTH_SHIFT;
	68	tick_length_base += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
04b617e7	69	tick_length_base += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
b0ee7556 RZ	70
	71	do_div(tick_length_base, HZ);
	72
	73	tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT;
	74	}
	75
4c7ee8de	76	/*
	77	* this routine handles the overflow of the microsecond field
	78	*
	79	* The tricky bits of code to handle the accurate clock support
	80	* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
	81	* They were originally developed for SUN and DEC kernels.
	82	* All the kudos should go to Dave for this stuff.
	83	*/
	84	void second_overflow(void)
	85	{
3d3675cc	86	long time_adj;
4c7ee8de	87
4c7ee8de	88	/* Bump the maxerror field */
97eebe13	89	time_maxerror += MAXFREQ >> SHIFT_USEC;
4c7ee8de	90	if (time_maxerror > NTP_PHASE_LIMIT) {
	91	time_maxerror = NTP_PHASE_LIMIT;
	92	time_status \|= STA_UNSYNC;
	93	}
	94
	95	/*
	96	* Leap second processing. If in leap-insert state at the end of the
	97	* day, the system clock is set back one second; if in leap-delete
	98	* state, the system clock is set ahead one second. The microtime()
	99	* routine or external clock driver will insure that reported time is
	100	* always monotonic. The ugly divides should be replaced.
	101	*/
	102	switch (time_state) {
	103	case TIME_OK:
	104	if (time_status & STA_INS)
	105	time_state = TIME_INS;
	106	else if (time_status & STA_DEL)
	107	time_state = TIME_DEL;
	108	break;
	109	case TIME_INS:
	110	if (xtime.tv_sec % 86400 == 0) {
	111	xtime.tv_sec--;
	112	wall_to_monotonic.tv_sec++;
	113	/*
	114	* The timer interpolator will make time change
	115	* gradually instead of an immediate jump by one second
	116	*/
	117	time_interpolator_update(-NSEC_PER_SEC);
	118	time_state = TIME_OOP;
	119	clock_was_set();
	120	printk(KERN_NOTICE "Clock: inserting leap second "
	121	"23:59:60 UTC\n");
	122	}
	123	break;
	124	case TIME_DEL:
	125	if ((xtime.tv_sec + 1) % 86400 == 0) {
	126	xtime.tv_sec++;
	127	wall_to_monotonic.tv_sec--;
	128	/*
	129	* Use of time interpolator for a gradual change of
	130	* time
	131	*/
	132	time_interpolator_update(NSEC_PER_SEC);
	133	time_state = TIME_WAIT;
	134	clock_was_set();
	135	printk(KERN_NOTICE "Clock: deleting leap second "
	136	"23:59:59 UTC\n");
	137	}
	138	break;
	139	case TIME_OOP:
	140	time_state = TIME_WAIT;
	141	break;
	142	case TIME_WAIT:
	143	if (!(time_status & (STA_INS \| STA_DEL)))
	144	time_state = TIME_OK;
	145	}
	146
	147	/*
f1992393 RZ	148	* Compute the phase adjustment for the next second. The offset is
f1992393 RZ	149	* reduced by a fixed factor times the time constant.
4c7ee8de	150	*/
b0ee7556	151	tick_length = tick_length_base;
f1992393	152	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
3d3675cc RZ	153	time_offset -= time_adj;
3d3675cc RZ	154	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
4c7ee8de	155
8f807f8d RZ	156	if (unlikely(time_adjust)) {
	157	if (time_adjust > MAX_TICKADJ) {
	158	time_adjust -= MAX_TICKADJ;
	159	tick_length += MAX_TICKADJ_SCALED;
	160	} else if (time_adjust < -MAX_TICKADJ) {
	161	time_adjust += MAX_TICKADJ;
	162	tick_length -= MAX_TICKADJ_SCALED;
	163	} else {
	164	time_adjust = 0;
	165	tick_length += (s64)(time_adjust * NSEC_PER_USEC /
	166	HZ) << TICK_LENGTH_SHIFT;
	167	}
4c7ee8de	168	}
	169	}
	170
	171	/*
	172	* Return how long ticks are at the moment, that is, how much time
	173	* update_wall_time_one_tick will add to xtime next time we call it
	174	* (assuming no calls to do_adjtimex in the meantime).
	175	* The return value is in fixed-point nanoseconds shifted by the
	176	* specified number of bits to the right of the binary point.
	177	* This function has no side-effects.
	178	*/
	179	u64 current_tick_length(void)
	180	{
8f807f8d	181	return tick_length;
4c7ee8de	182	}
	183
	184
	185	void __attribute__ ((weak)) notify_arch_cmos_timer(void)
	186	{
	187	return;
	188	}
	189
	190	/* adjtimex mainly allows reading (and writing, if superuser) of
	191	* kernel time-keeping variables. used by xntpd.
	192	*/
	193	int do_adjtimex(struct timex *txc)
	194	{
	195	long ltemp, mtemp, save_adjust;
f1992393	196	s64 freq_adj, temp64;
4c7ee8de	197	int result;
	198
	199	/* In order to modify anything, you gotta be super-user! */
	200	if (txc->modes && !capable(CAP_SYS_TIME))
	201	return -EPERM;
	202
	203	/* Now we validate the data before disabling interrupts */
	204
	205	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
	206	/* singleshot must not be used with any other mode bits */
	207	if (txc->modes != ADJ_OFFSET_SINGLESHOT)
	208	return -EINVAL;
	209
	210	if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
	211	/* adjustment Offset limited to +- .512 seconds */
	212	if (txc->offset <= - MAXPHASE \|\| txc->offset >= MAXPHASE )
	213	return -EINVAL;
	214
	215	/* if the quartz is off by more than 10% something is VERY wrong ! */
	216	if (txc->modes & ADJ_TICK)
	217	if (txc->tick < 900000/USER_HZ \|\|
	218	txc->tick > 1100000/USER_HZ)
	219	return -EINVAL;
	220
	221	write_seqlock_irq(&xtime_lock);
	222	result = time_state; /* mostly `TIME_OK' */
	223
	224	/* Save for later - semantics of adjtime is to return old value */
8f807f8d	225	save_adjust = time_adjust;
4c7ee8de	226
	227	#if 0 /* STA_CLOCKERR is never set yet */
	228	time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
	229	#endif
	230	/* If there are input parameters, then process them */
	231	if (txc->modes)
	232	{
	233	if (txc->modes & ADJ_STATUS) /* only set allowed bits */
	234	time_status = (txc->status & ~STA_RONLY) \|
	235	(time_status & STA_RONLY);
	236
	237	if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
	238	if (txc->freq > MAXFREQ \|\| txc->freq < -MAXFREQ) {
	239	result = -EINVAL;
	240	goto leave;
	241	}
04b617e7	242	time_freq = ((s64)txc->freq * NSEC_PER_USEC) >> (SHIFT_USEC - SHIFT_NSEC);
4c7ee8de	243	}
	244
	245	if (txc->modes & ADJ_MAXERROR) {
	246	if (txc->maxerror < 0 \|\| txc->maxerror >= NTP_PHASE_LIMIT) {
	247	result = -EINVAL;
	248	goto leave;
	249	}
	250	time_maxerror = txc->maxerror;
	251	}
	252
	253	if (txc->modes & ADJ_ESTERROR) {
	254	if (txc->esterror < 0 \|\| txc->esterror >= NTP_PHASE_LIMIT) {
	255	result = -EINVAL;
	256	goto leave;
	257	}
	258	time_esterror = txc->esterror;
	259	}
	260
	261	if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
	262	if (txc->constant < 0) { /* NTP v4 uses values > 6 */
	263	result = -EINVAL;
	264	goto leave;
	265	}
f1992393	266	time_constant = min(txc->constant + 4, (long)MAXTC);
4c7ee8de	267	}
	268
	269	if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
	270	if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
	271	/* adjtime() is independent from ntp_adjtime() */
8f807f8d	272	time_adjust = txc->offset;
4c7ee8de	273	}
4c7ee8de	274	else if (time_status & STA_PLL) {
04b617e7	275	ltemp = txc->offset * NSEC_PER_USEC;
4c7ee8de	276
	277	/*
	278	* Scale the phase adjustment and
	279	* clamp to the operating range.
	280	*/
04b617e7 RZ	281	time_offset = min(ltemp, MAXPHASE * NSEC_PER_USEC);
04b617e7 RZ	282	time_offset = max(time_offset, -MAXPHASE * NSEC_PER_USEC);
4c7ee8de	283
	284	/*
	285	* Select whether the frequency is to be controlled
	286	* and in which mode (PLL or FLL). Clamp to the operating
	287	* range. Ugly multiply/divide should be replaced someday.
	288	*/
	289
	290	if (time_status & STA_FREQHOLD \|\| time_reftime == 0)
	291	time_reftime = xtime.tv_sec;
	292	mtemp = xtime.tv_sec - time_reftime;
	293	time_reftime = xtime.tv_sec;
f1992393 RZ	294
	295	freq_adj = (s64)time_offset * mtemp;
	296	freq_adj = shift_right(freq_adj, time_constant * 2 +
	297	(SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
	298	if (mtemp >= MINSEC && (time_status & STA_FLL \|\| mtemp > MAXSEC)) {
	299	temp64 = (s64)time_offset << (SHIFT_NSEC - SHIFT_FLL);
	300	if (time_offset < 0) {
	301	temp64 = -temp64;
	302	do_div(temp64, mtemp);
	303	freq_adj -= temp64;
	304	} else {
	305	do_div(temp64, mtemp);
	306	freq_adj += temp64;
	307	}
4c7ee8de	308	}
04b617e7 RZ	309	freq_adj += time_freq;
	310	freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
	311	time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
	312	time_offset = (time_offset / HZ) << SHIFT_UPDATE;
4c7ee8de	313	} /* STA_PLL */
4c7ee8de	314	} /* txc->modes & ADJ_OFFSET */
b0ee7556	315	if (txc->modes & ADJ_TICK)
4c7ee8de	316	tick_usec = txc->tick;
b0ee7556	317
dc6a43e4	318	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
b0ee7556	319	ntp_update_frequency();
4c7ee8de	320	} /* txc->modes */
	321	leave: if ((time_status & (STA_UNSYNC\|STA_CLOCKERR)) != 0)
	322	result = TIME_ERROR;
	323
	324	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
	325	txc->offset = save_adjust;
3d3675cc RZ	326	else
3d3675cc RZ	327	txc->offset = shift_right(time_offset, SHIFT_UPDATE) * HZ / 1000;
04b617e7	328	txc->freq = (time_freq / NSEC_PER_USEC) << (SHIFT_USEC - SHIFT_NSEC);
4c7ee8de	329	txc->maxerror = time_maxerror;
	330	txc->esterror = time_esterror;
	331	txc->status = time_status;
	332	txc->constant = time_constant;
	333	txc->precision = time_precision;
97eebe13	334	txc->tolerance = MAXFREQ;
4c7ee8de	335	txc->tick = tick_usec;
	336
	337	/* PPS is not implemented, so these are zero */
	338	txc->ppsfreq = 0;
	339	txc->jitter = 0;
	340	txc->shift = 0;
	341	txc->stabil = 0;
	342	txc->jitcnt = 0;
	343	txc->calcnt = 0;
	344	txc->errcnt = 0;
	345	txc->stbcnt = 0;
	346	write_sequnlock_irq(&xtime_lock);
	347	do_gettimeofday(&txc->time);
	348	notify_arch_cmos_timer();
	349	return(result);
	350	}