[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  It has been superseded by the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>

include/linux/timex.h

@@ -224,66 +224,6 @@ static inline int ntp_synced(void)
 	__x < 0 ? -(-__x >> __s) : __x >> __s;	\
 })
 
-
-#ifdef CONFIG_TIME_INTERPOLATION
-
-#define TIME_SOURCE_CPU 0
-#define TIME_SOURCE_MMIO64 1
-#define TIME_SOURCE_MMIO32 2
-#define TIME_SOURCE_FUNCTION 3
-
-/* For proper operations time_interpolator clocks must run slightly slower
- * than the standard clock since the interpolator may only correct by having
- * time jump forward during a tick. A slower clock is usually a side effect
- * of the integer divide of the nanoseconds in a second by the frequency.
- * The accuracy of the division can be increased by specifying a shift.
- * However, this may cause the clock not to be slow enough.
- * The interpolator will self-tune the clock by slowing down if no
- * resets occur or speeding up if the time jumps per analysis cycle
- * become too high.
- *
- * Setting jitter compensates for a fluctuating timesource by comparing
- * to the last value read from the timesource to insure that an earlier value
- * is not returned by a later call. The price to pay
- * for the compensation is that the timer routines are not as scalable anymore.
- */
-
-struct time_interpolator {
-	u16 source;			/* time source flags */
-	u8 shift;			/* increases accuracy of multiply by shifting. */
-				/* Note that bits may be lost if shift is set too high */
-	u8 jitter;			/* if set compensate for fluctuations */
-	u32 nsec_per_cyc;		/* set by register_time_interpolator() */
-	void *addr;			/* address of counter or function */
-	cycles_t mask;			/* mask the valid bits of the counter */
-	unsigned long offset;		/* nsec offset at last update of interpolator */
-	u64 last_counter;		/* counter value in units of the counter at last update */
-	cycles_t last_cycle;		/* Last timer value if TIME_SOURCE_JITTER is set */
-	u64 frequency;			/* frequency in counts/second */
-	long drift;			/* drift in parts-per-million (or -1) */
-	unsigned long skips;		/* skips forward */
-	unsigned long ns_skipped;	/* nanoseconds skipped */
-	struct time_interpolator *next;
-};
-
-extern void register_time_interpolator(struct time_interpolator *);
-extern void unregister_time_interpolator(struct time_interpolator *);
-extern void time_interpolator_reset(void);
-extern unsigned long time_interpolator_get_offset(void);
-extern void time_interpolator_update(long delta_nsec);
-
-#else /* !CONFIG_TIME_INTERPOLATION */
-
-static inline void time_interpolator_reset(void)
-{
-}
-
-static inline void time_interpolator_update(long delta_nsec)
-{
-}
-
-#endif /* !CONFIG_TIME_INTERPOLATION */
-
 #define TICK_LENGTH_SHIFT	32
 
 #ifdef CONFIG_NO_HZ

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

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");

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);