[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;

/* Don't completely fail for HZ > 500.  */
int tickadj = 500/HZ ? : 1;		/* microsecs */

/*
 * 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_tolerance = MAXFREQ;		/* frequency tolerance (ppm)	*/
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;
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;
	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 * NSEC_PER_USEC) << (TICK_LENGTH_SHIFT - SHIFT_USEC);

	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 += time_tolerance >> 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. 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.
	 */
	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_offset -= time_adj;
	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
}

/*
 * Returns how many microseconds we need to add to xtime this tick
 * in doing an adjustment requested with adjtime.
 */
static long adjtime_adjustment(void)
{
	long time_adjust_step;

	time_adjust_step = time_adjust;
	if (time_adjust_step) {
		/*
		 * We are doing an adjtime thing.  Prepare time_adjust_step to
		 * be within bounds.  Note that a positive time_adjust means we
		 * want the clock to run faster.
		 *
		 * Limit the amount of the step to be in the range
		 * -tickadj .. +tickadj
		 */
		time_adjust_step = min(time_adjust_step, (long)tickadj);
		time_adjust_step = max(time_adjust_step, (long)-tickadj);
	}
	return time_adjust_step;
}

/* in the NTP reference this is called "hardclock()" */
void update_ntp_one_tick(void)
{
	long time_adjust_step;

	time_adjust_step = adjtime_adjustment();
	if (time_adjust_step)
		/* Reduce by this step the amount of time left  */
		time_adjust -= time_adjust_step;

	/* Changes by adjtime() do not take effect till next tick. */
	if (time_next_adjust != 0) {
		time_adjust = time_next_adjust;
		time_next_adjust = 0;
	}
}

/*
 * 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)
{
	u64 ret;

	/* calculate the finest interval NTP will allow.
	 */
	ret = tick_length;
	ret += (u64)(adjtime_adjustment() * 1000) << TICK_LENGTH_SHIFT;

	return ret;
}


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;
	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_next_adjust ? time_next_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 = txc->freq;
	    }

	    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 = txc->constant;
	    }

	    if (txc->modes & ADJ_OFFSET) {	/* values checked earlier */
		if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
		    /* adjtime() is independent from ntp_adjtime() */
		    if ((time_next_adjust = txc->offset) == 0)
			 time_adjust = 0;
		}
		else if (time_status & STA_PLL) {
		    ltemp = txc->offset;

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

		    /*
		     * 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;
		    if (time_status & STA_FLL) {
		        if (mtemp >= MINSEC) {
			    ltemp = ((time_offset << 12) / mtemp) << (SHIFT_USEC - 12);
			    time_freq += shift_right(ltemp, SHIFT_KH);
			} 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 +
						       time_constant +
						       SHIFT_KF - SHIFT_USEC));
			} else /* calibration interval too long (p. 12) */
				result = TIME_ERROR;
		    }
		    time_freq = min(time_freq, time_tolerance);
		    time_freq = max(time_freq, -time_tolerance);
		    time_offset = (time_offset * NSEC_PER_USEC / 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;
	txc->maxerror	   = time_maxerror;
	txc->esterror	   = time_esterror;
	txc->status	   = time_status;
	txc->constant	   = time_constant;
	txc->precision	   = time_precision;
	txc->tolerance	   = time_tolerance;
	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
4c7ee8de	25	/* Don't completely fail for HZ > 500. */
	26	int tickadj = 500/HZ ? : 1; /* microsecs */
	27
	28	/*
	29	* phase-lock loop variables
	30	*/
	31	/* TIME_ERROR prevents overwriting the CMOS clock */
	32	int time_state = TIME_OK; /* clock synchronization status */
	33	int time_status = STA_UNSYNC; /* clock status bits */
3d3675cc	34	long time_offset; /* time adjustment (ns) */
4c7ee8de	35	long time_constant = 2; /* pll time constant */
	36	long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
	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) */
	42	long time_adjust;
	43	long time_next_adjust;
	44
b0ee7556 RZ	45	/**
	46	* ntp_clear - Clears the NTP state variables
	47	*
	48	* Must be called while holding a write on the xtime_lock
	49	*/
	50	void ntp_clear(void)
	51	{
	52	time_adjust = 0; /* stop active adjtime() */
	53	time_status \|= STA_UNSYNC;
	54	time_maxerror = NTP_PHASE_LIMIT;
	55	time_esterror = NTP_PHASE_LIMIT;
	56
	57	ntp_update_frequency();
	58
	59	tick_length = tick_length_base;
3d3675cc	60	time_offset = 0;
b0ee7556 RZ	61	}
	62
	63	#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE)
	64	#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / (s64)CLOCK_TICK_RATE)
	65
	66	void ntp_update_frequency(void)
	67	{
	68	tick_length_base = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) << TICK_LENGTH_SHIFT;
	69	tick_length_base += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
dc6a43e4	70	tick_length_base += ((s64)time_freq * NSEC_PER_USEC) << (TICK_LENGTH_SHIFT - SHIFT_USEC);
b0ee7556 RZ	71
	72	do_div(tick_length_base, HZ);
	73
	74	tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT;
	75	}
	76
4c7ee8de	77	/*
	78	* this routine handles the overflow of the microsecond field
	79	*
	80	* The tricky bits of code to handle the accurate clock support
	81	* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
	82	* They were originally developed for SUN and DEC kernels.
	83	* All the kudos should go to Dave for this stuff.
	84	*/
	85	void second_overflow(void)
	86	{
3d3675cc	87	long time_adj;
4c7ee8de	88
	89	/* Bump the maxerror field */
	90	time_maxerror += time_tolerance >> SHIFT_USEC;
	91	if (time_maxerror > NTP_PHASE_LIMIT) {
	92	time_maxerror = NTP_PHASE_LIMIT;
	93	time_status \|= STA_UNSYNC;
	94	}
	95
	96	/*
	97	* Leap second processing. If in leap-insert state at the end of the
	98	* day, the system clock is set back one second; if in leap-delete
	99	* state, the system clock is set ahead one second. The microtime()
	100	* routine or external clock driver will insure that reported time is
	101	* always monotonic. The ugly divides should be replaced.
	102	*/
	103	switch (time_state) {
	104	case TIME_OK:
	105	if (time_status & STA_INS)
	106	time_state = TIME_INS;
	107	else if (time_status & STA_DEL)
	108	time_state = TIME_DEL;
	109	break;
	110	case TIME_INS:
	111	if (xtime.tv_sec % 86400 == 0) {
	112	xtime.tv_sec--;
	113	wall_to_monotonic.tv_sec++;
	114	/*
	115	* The timer interpolator will make time change
	116	* gradually instead of an immediate jump by one second
	117	*/
	118	time_interpolator_update(-NSEC_PER_SEC);
	119	time_state = TIME_OOP;
	120	clock_was_set();
	121	printk(KERN_NOTICE "Clock: inserting leap second "
	122	"23:59:60 UTC\n");
	123	}
	124	break;
	125	case TIME_DEL:
	126	if ((xtime.tv_sec + 1) % 86400 == 0) {
	127	xtime.tv_sec++;
	128	wall_to_monotonic.tv_sec--;
	129	/*
	130	* Use of time interpolator for a gradual change of
	131	* time
	132	*/
	133	time_interpolator_update(NSEC_PER_SEC);
	134	time_state = TIME_WAIT;
	135	clock_was_set();
	136	printk(KERN_NOTICE "Clock: deleting leap second "
	137	"23:59:59 UTC\n");
	138	}
	139	break;
	140	case TIME_OOP:
	141	time_state = TIME_WAIT;
	142	break;
	143	case TIME_WAIT:
	144	if (!(time_status & (STA_INS \| STA_DEL)))
	145	time_state = TIME_OK;
	146	}
	147
	148	/*
	149	* Compute the phase adjustment for the next second. In PLL mode, the
	150	* offset is reduced by a fixed factor times the time constant. In FLL
	151	* mode the offset is used directly. In either mode, the maximum phase
152	* adjustment for each second is clamped so as to spread the adjustment
153	* over not more than the number of seconds between updates.
154	*/
b0ee7556	155	tick_length = tick_length_base;
3d3675cc RZ	156	time_adj = time_offset;
	157	if (!(time_status & STA_FLL))
	158	time_adj = shift_right(time_adj, SHIFT_KG + time_constant);
	159	time_adj = min(time_adj, -((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC);
	160	time_adj = max(time_adj, ((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC);
	161	time_offset -= time_adj;
	162	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
4c7ee8de	163	}
	164
	165	/*
	166	* Returns how many microseconds we need to add to xtime this tick
	167	* in doing an adjustment requested with adjtime.
	168	*/
	169	static long adjtime_adjustment(void)
	170	{
	171	long time_adjust_step;
	172
	173	time_adjust_step = time_adjust;
	174	if (time_adjust_step) {
	175	/*
	176	* We are doing an adjtime thing. Prepare time_adjust_step to
	177	* be within bounds. Note that a positive time_adjust means we
	178	* want the clock to run faster.
	179	*
	180	* Limit the amount of the step to be in the range
	181	* -tickadj .. +tickadj
	182	*/
	183	time_adjust_step = min(time_adjust_step, (long)tickadj);
	184	time_adjust_step = max(time_adjust_step, (long)-tickadj);
	185	}
	186	return time_adjust_step;
	187	}
	188
	189	/* in the NTP reference this is called "hardclock()" */
	190	void update_ntp_one_tick(void)
	191	{
	192	long time_adjust_step;
	193
	194	time_adjust_step = adjtime_adjustment();
	195	if (time_adjust_step)
	196	/* Reduce by this step the amount of time left */
	197	time_adjust -= time_adjust_step;
	198
	199	/* Changes by adjtime() do not take effect till next tick. */
	200	if (time_next_adjust != 0) {
	201	time_adjust = time_next_adjust;
	202	time_next_adjust = 0;
	203	}
	204	}
	205
	206	/*
	207	* Return how long ticks are at the moment, that is, how much time
	208	* update_wall_time_one_tick will add to xtime next time we call it
	209	* (assuming no calls to do_adjtimex in the meantime).
	210	* The return value is in fixed-point nanoseconds shifted by the
	211	* specified number of bits to the right of the binary point.
	212	* This function has no side-effects.
	213	*/
	214	u64 current_tick_length(void)
	215	{
4c7ee8de	216	u64 ret;
	217
	218	/* calculate the finest interval NTP will allow.
4c7ee8de	219	*/
b0ee7556 RZ	220	ret = tick_length;
b0ee7556 RZ	221	ret += (u64)(adjtime_adjustment() * 1000) << TICK_LENGTH_SHIFT;
4c7ee8de	222
	223	return ret;
	224	}
	225
	226
	227	void __attribute__ ((weak)) notify_arch_cmos_timer(void)
	228	{
	229	return;
	230	}
	231
	232	/* adjtimex mainly allows reading (and writing, if superuser) of
	233	* kernel time-keeping variables. used by xntpd.
	234	*/
	235	int do_adjtimex(struct timex *txc)
	236	{
	237	long ltemp, mtemp, save_adjust;
	238	int result;
	239
	240	/* In order to modify anything, you gotta be super-user! */
	241	if (txc->modes && !capable(CAP_SYS_TIME))
	242	return -EPERM;
	243
	244	/* Now we validate the data before disabling interrupts */
	245
	246	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
	247	/* singleshot must not be used with any other mode bits */
	248	if (txc->modes != ADJ_OFFSET_SINGLESHOT)
	249	return -EINVAL;
	250
	251	if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
	252	/* adjustment Offset limited to +- .512 seconds */
	253	if (txc->offset <= - MAXPHASE \|\| txc->offset >= MAXPHASE )
	254	return -EINVAL;
	255
	256	/* if the quartz is off by more than 10% something is VERY wrong ! */
	257	if (txc->modes & ADJ_TICK)
	258	if (txc->tick < 900000/USER_HZ \|\|
	259	txc->tick > 1100000/USER_HZ)
	260	return -EINVAL;
	261
	262	write_seqlock_irq(&xtime_lock);
	263	result = time_state; /* mostly `TIME_OK' */
	264
	265	/* Save for later - semantics of adjtime is to return old value */
	266	save_adjust = time_next_adjust ? time_next_adjust : time_adjust;
	267
	268	#if 0 /* STA_CLOCKERR is never set yet */
	269	time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
	270	#endif
	271	/* If there are input parameters, then process them */
	272	if (txc->modes)
	273	{
	274	if (txc->modes & ADJ_STATUS) /* only set allowed bits */
	275	time_status = (txc->status & ~STA_RONLY) \|
	276	(time_status & STA_RONLY);
	277
	278	if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
	279	if (txc->freq > MAXFREQ \|\| txc->freq < -MAXFREQ) {
	280	result = -EINVAL;
	281	goto leave;
	282	}
	283	time_freq = txc->freq;
	284	}
	285
286	if (txc->modes & ADJ_MAXERROR) {
287	if (txc->maxerror < 0 \|\| txc->maxerror >= NTP_PHASE_LIMIT) {
288	result = -EINVAL;
289	goto leave;
290	}
291	time_maxerror = txc->maxerror;
292	}
293
294	if (txc->modes & ADJ_ESTERROR) {
295	if (txc->esterror < 0 \|\| txc->esterror >= NTP_PHASE_LIMIT) {
296	result = -EINVAL;
297	goto leave;
298	}
299	time_esterror = txc->esterror;
300	}
301
302	if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
303	if (txc->constant < 0) { /* NTP v4 uses values > 6 */
304	result = -EINVAL;
305	goto leave;
306	}
307	time_constant = txc->constant;
308	}
309
310	if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
311	if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
312	/* adjtime() is independent from ntp_adjtime() */
313	if ((time_next_adjust = txc->offset) == 0)
314	time_adjust = 0;
315	}
316	else if (time_status & STA_PLL) {
317	ltemp = txc->offset;
318
319	/*
320	* Scale the phase adjustment and
321	* clamp to the operating range.
322	*/
3d3675cc RZ	323	time_offset = min(ltemp, MAXPHASE);
3d3675cc RZ	324	time_offset = max(time_offset, -MAXPHASE);
4c7ee8de	325
	326	/*
	327	* Select whether the frequency is to be controlled
	328	* and in which mode (PLL or FLL). Clamp to the operating
	329	* range. Ugly multiply/divide should be replaced someday.
	330	*/
	331
	332	if (time_status & STA_FREQHOLD \|\| time_reftime == 0)
	333	time_reftime = xtime.tv_sec;
	334	mtemp = xtime.tv_sec - time_reftime;
	335	time_reftime = xtime.tv_sec;
	336	if (time_status & STA_FLL) {
	337	if (mtemp >= MINSEC) {
3d3675cc	338	ltemp = ((time_offset << 12) / mtemp) << (SHIFT_USEC - 12);
4c7ee8de	339	time_freq += shift_right(ltemp, SHIFT_KH);
	340	} else /* calibration interval too short (p. 12) */
	341	result = TIME_ERROR;
	342	} else { /* PLL mode */
	343	if (mtemp < MAXSEC) {
	344	ltemp *= mtemp;
	345	time_freq += shift_right(ltemp,(time_constant +
	346	time_constant +
	347	SHIFT_KF - SHIFT_USEC));
	348	} else /* calibration interval too long (p. 12) */
	349	result = TIME_ERROR;
	350	}
	351	time_freq = min(time_freq, time_tolerance);
	352	time_freq = max(time_freq, -time_tolerance);
3d3675cc	353	time_offset = (time_offset * NSEC_PER_USEC / HZ) << SHIFT_UPDATE;
4c7ee8de	354	} /* STA_PLL */
4c7ee8de	355	} /* txc->modes & ADJ_OFFSET */
b0ee7556	356	if (txc->modes & ADJ_TICK)
4c7ee8de	357	tick_usec = txc->tick;
b0ee7556	358
dc6a43e4	359	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
b0ee7556	360	ntp_update_frequency();
4c7ee8de	361	} /* txc->modes */
	362	leave: if ((time_status & (STA_UNSYNC\|STA_CLOCKERR)) != 0)
	363	result = TIME_ERROR;
	364
	365	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
	366	txc->offset = save_adjust;
3d3675cc RZ	367	else
3d3675cc RZ	368	txc->offset = shift_right(time_offset, SHIFT_UPDATE) * HZ / 1000;
4c7ee8de	369	txc->freq = time_freq;
	370	txc->maxerror = time_maxerror;
	371	txc->esterror = time_esterror;
	372	txc->status = time_status;
	373	txc->constant = time_constant;
	374	txc->precision = time_precision;
	375	txc->tolerance = time_tolerance;
	376	txc->tick = tick_usec;
	377
	378	/* PPS is not implemented, so these are zero */
	379	txc->ppsfreq = 0;
	380	txc->jitter = 0;
	381	txc->shift = 0;
	382	txc->stabil = 0;
	383	txc->jitcnt = 0;
	384	txc->calcnt = 0;
	385	txc->errcnt = 0;
	386	txc->stbcnt = 0;
	387	write_sequnlock_irq(&xtime_lock);
	388	do_gettimeofday(&txc->time);
	389	notify_arch_cmos_timer();
	390	return(result);
	391	}