[IA64] remove time interpolator

Remove time_interpolator code (This is generic code, but
only user was ia64.  It has been superseded by the
CONFIG_GENERIC_TIME code).

Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Peter Keilty <peter.keilty@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

4 files changed, 0 insertions, 290 deletions

diff --git a/kernel/time.c b/kernel/time.c
index ffe19149d770..e325597f5bf5 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -136,7 +136,6 @@ static inline void warp_clock(void)
 	write_seqlock_irq(&xtime_lock);
 	wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60;
 	xtime.tv_sec += sys_tz.tz_minuteswest * 60;
-	time_interpolator_reset();
 	write_sequnlock_irq(&xtime_lock);
 	clock_was_set();
 }
@@ -309,92 +308,6 @@ struct timespec timespec_trunc(struct timespec t, unsigned gran)
 }
 EXPORT_SYMBOL(timespec_trunc);
 
-#ifdef CONFIG_TIME_INTERPOLATION
-void getnstimeofday (struct timespec *tv)
-{
-	unsigned long seq,sec,nsec;
-
-	do {
-		seq = read_seqbegin(&xtime_lock);
-		sec = xtime.tv_sec;
-		nsec = xtime.tv_nsec+time_interpolator_get_offset();
-	} while (unlikely(read_seqretry(&xtime_lock, seq)));
-
-	while (unlikely(nsec >= NSEC_PER_SEC)) {
-		nsec -= NSEC_PER_SEC;
-		++sec;
-	}
-	tv->tv_sec = sec;
-	tv->tv_nsec = nsec;
-}
-EXPORT_SYMBOL_GPL(getnstimeofday);
-
-int do_settimeofday (struct timespec *tv)
-{
-	time_t wtm_sec, sec = tv->tv_sec;
-	long wtm_nsec, nsec = tv->tv_nsec;
-
-	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-		return -EINVAL;
-
-	write_seqlock_irq(&xtime_lock);
-	{
-		wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-		wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
-		set_normalized_timespec(&xtime, sec, nsec);
-		set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
-		time_adjust = 0;		/* stop active adjtime() */
-		time_status |= STA_UNSYNC;
-		time_maxerror = NTP_PHASE_LIMIT;
-		time_esterror = NTP_PHASE_LIMIT;
-		time_interpolator_reset();
-	}
-	write_sequnlock_irq(&xtime_lock);
-	clock_was_set();
-	return 0;
-}
-EXPORT_SYMBOL(do_settimeofday);
-
-void do_gettimeofday (struct timeval *tv)
-{
-	unsigned long seq, nsec, usec, sec, offset;
-	do {
-		seq = read_seqbegin(&xtime_lock);
-		offset = time_interpolator_get_offset();
-		sec = xtime.tv_sec;
-		nsec = xtime.tv_nsec;
-	} while (unlikely(read_seqretry(&xtime_lock, seq)));
-
-	usec = (nsec + offset) / 1000;
-
-	while (unlikely(usec >= USEC_PER_SEC)) {
-		usec -= USEC_PER_SEC;
-		++sec;
-	}
-
-	tv->tv_sec = sec;
-	tv->tv_usec = usec;
-
-	/*
-	 * Make sure xtime.tv_sec [returned by sys_time()] always
-	 * follows the gettimeofday() result precisely. This
-	 * condition is extremely unlikely, it can hit at most
-	 * once per second:
-	 */
-	if (unlikely(xtime.tv_sec != tv->tv_sec)) {
-		unsigned long flags;
-
-		write_seqlock_irqsave(&xtime_lock, flags);
-		update_wall_time();
-		write_sequnlock_irqrestore(&xtime_lock, flags);
-	}
-}
-EXPORT_SYMBOL(do_gettimeofday);
-
-#else	/* CONFIG_TIME_INTERPOLATION */
-
 #ifndef CONFIG_GENERIC_TIME
 /*
  * Simulate gettimeofday using do_gettimeofday which only allows a timeval
@@ -410,7 +323,6 @@ void getnstimeofday(struct timespec *tv)
 }
 EXPORT_SYMBOL_GPL(getnstimeofday);
 #endif
-#endif	/* CONFIG_TIME_INTERPOLATION */
 
 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
  * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 438c6b723ee2..b5e352597cbb 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -116,11 +116,6 @@ void second_overflow(void)
 		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;
 			printk(KERN_NOTICE "Clock: inserting leap second "
 					"23:59:60 UTC\n");
@@ -130,11 +125,6 @@ void second_overflow(void)
 		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;
 			printk(KERN_NOTICE "Clock: deleting leap second "
 					"23:59:59 UTC\n");
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 728cedfd3cbd..027d46c906e0 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -466,10 +466,6 @@ void update_wall_time(void)
 			second_overflow();
 		}
 
-		/* interpolator bits */
-		time_interpolator_update(clock->xtime_interval
-						>> clock->shift);
-
 		/* accumulate error between NTP and clock interval */
 		clock->error += current_tick_length();
 		clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
diff --git a/kernel/timer.c b/kernel/timer.c
index b7792fb03387..dbc03ab14eed 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1349,194 +1349,6 @@ void __init init_timers(void)
 	open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
 }
 
-#ifdef CONFIG_TIME_INTERPOLATION
-
-struct time_interpolator *time_interpolator __read_mostly;
-static struct time_interpolator *time_interpolator_list __read_mostly;
-static DEFINE_SPINLOCK(time_interpolator_lock);
-
-static inline cycles_t time_interpolator_get_cycles(unsigned int src)
-{
-	unsigned long (*x)(void);
-
-	switch (src)
-	{
-		case TIME_SOURCE_FUNCTION:
-			x = time_interpolator->addr;
-			return x();
-
-		case TIME_SOURCE_MMIO64	:
-			return readq_relaxed((void __iomem *)time_interpolator->addr);
-
-		case TIME_SOURCE_MMIO32	:
-			return readl_relaxed((void __iomem *)time_interpolator->addr);
-
-		default: return get_cycles();
-	}
-}
-
-static inline u64 time_interpolator_get_counter(int writelock)
-{
-	unsigned int src = time_interpolator->source;
-
-	if (time_interpolator->jitter)
-	{
-		cycles_t lcycle;
-		cycles_t now;
-
-		do {
-			lcycle = time_interpolator->last_cycle;
-			now = time_interpolator_get_cycles(src);
-			if (lcycle && time_after(lcycle, now))
-				return lcycle;
-
-			/* When holding the xtime write lock, there's no need
-			 * to add the overhead of the cmpxchg.  Readers are
-			 * force to retry until the write lock is released.
-			 */
-			if (writelock) {
-				time_interpolator->last_cycle = now;
-				return now;
-			}
-			/* Keep track of the last timer value returned. The use of cmpxchg here
-			 * will cause contention in an SMP environment.
-			 */
-		} while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
-		return now;
-	}
-	else
-		return time_interpolator_get_cycles(src);
-}
-
-void time_interpolator_reset(void)
-{
-	time_interpolator->offset = 0;
-	time_interpolator->last_counter = time_interpolator_get_counter(1);
-}
-
-#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
-
-unsigned long time_interpolator_get_offset(void)
-{
-	/* If we do not have a time interpolator set up then just return zero */
-	if (!time_interpolator)
-		return 0;
-
-	return time_interpolator->offset +
-		GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
-}
-
-#define INTERPOLATOR_ADJUST 65536
-#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
-
-void time_interpolator_update(long delta_nsec)
-{
-	u64 counter;
-	unsigned long offset;
-
-	/* If there is no time interpolator set up then do nothing */
-	if (!time_interpolator)
-		return;
-
-	/*
-	 * The interpolator compensates for late ticks by accumulating the late
-	 * time in time_interpolator->offset. A tick earlier than expected will
-	 * lead to a reset of the offset and a corresponding jump of the clock
-	 * forward. Again this only works if the interpolator clock is running
-	 * slightly slower than the regular clock and the tuning logic insures
-	 * that.
-	 */
-
-	counter = time_interpolator_get_counter(1);
-	offset = time_interpolator->offset +
-			GET_TI_NSECS(counter, time_interpolator);
-
-	if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
-		time_interpolator->offset = offset - delta_nsec;
-	else {
-		time_interpolator->skips++;
-		time_interpolator->ns_skipped += delta_nsec - offset;
-		time_interpolator->offset = 0;
-	}
-	time_interpolator->last_counter = counter;
-
-	/* Tuning logic for time interpolator invoked every minute or so.
-	 * Decrease interpolator clock speed if no skips occurred and an offset is carried.
-	 * Increase interpolator clock speed if we skip too much time.
-	 */
-	if (jiffies % INTERPOLATOR_ADJUST == 0)
-	{
-		if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
-			time_interpolator->nsec_per_cyc--;
-		if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
-			time_interpolator->nsec_per_cyc++;
-		time_interpolator->skips = 0;
-		time_interpolator->ns_skipped = 0;
-	}
-}
-
-static inline int
-is_better_time_interpolator(struct time_interpolator *new)
-{
-	if (!time_interpolator)
-		return 1;
-	return new->frequency > 2*time_interpolator->frequency ||
-	    (unsigned long)new->drift < (unsigned long)time_interpolator->drift;
-}
-
-void
-register_time_interpolator(struct time_interpolator *ti)
-{
-	unsigned long flags;
-
-	/* Sanity check */
-	BUG_ON(ti->frequency == 0 || ti->mask == 0);
-
-	ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
-	spin_lock(&time_interpolator_lock);
-	write_seqlock_irqsave(&xtime_lock, flags);
-	if (is_better_time_interpolator(ti)) {
-		time_interpolator = ti;
-		time_interpolator_reset();
-	}
-	write_sequnlock_irqrestore(&xtime_lock, flags);
-
-	ti->next = time_interpolator_list;
-	time_interpolator_list = ti;
-	spin_unlock(&time_interpolator_lock);
-}
-
-void
-unregister_time_interpolator(struct time_interpolator *ti)
-{
-	struct time_interpolator *curr, **prev;
-	unsigned long flags;
-
-	spin_lock(&time_interpolator_lock);
-	prev = &time_interpolator_list;
-	for (curr = *prev; curr; curr = curr->next) {
-		if (curr == ti) {
-			*prev = curr->next;
-			break;
-		}
-		prev = &curr->next;
-	}
-
-	write_seqlock_irqsave(&xtime_lock, flags);
-	if (ti == time_interpolator) {
-		/* we lost the best time-interpolator: */
-		time_interpolator = NULL;
-		/* find the next-best interpolator */
-		for (curr = time_interpolator_list; curr; curr = curr->next)
-			if (is_better_time_interpolator(curr))
-				time_interpolator = curr;
-		time_interpolator_reset();
-	}
-	write_sequnlock_irqrestore(&xtime_lock, flags);
-	spin_unlock(&time_interpolator_lock);
-}
-#endif /* CONFIG_TIME_INTERPOLATION */
-
 /**
  * msleep - sleep safely even with waitqueue interruptions
  * @msecs: Time in milliseconds to sleep for