[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  It has been superseded by the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>

6 files changed, 0 insertions, 391 deletions

diff --git a/Documentation/time_interpolators.txt b/Documentation/time_interpolators.txt
deleted file mode 100644
index e3b60854fbc2..000000000000
--- a/Documentation/time_interpolators.txt
+++ /dev/null
@@ -1,41 +0,0 @@
-Time Interpolators
-------------------
-
-Time interpolators are a base of time calculation between timer ticks and
-allow an accurate determination of time down to the accuracy of the time
-source in nanoseconds.
-
-The architecture specific code typically provides gettimeofday and
-settimeofday under Linux. The time interpolator provides both if an arch
-defines CONFIG_TIME_INTERPOLATION. The arch still must set up timer tick
-operations and call the necessary functions to advance the clock.
-
-With the time interpolator a standardized interface exists for time
-interpolation between ticks. The provided logic is highly scalable
-and has been tested in SMP situations of up to 512 CPUs.
-
-If CONFIG_TIME_INTERPOLATION is defined then the architecture specific code
-(or the device drivers - like HPET) may register time interpolators.
-These are typically defined in the following way:
-
-static struct time_interpolator my_interpolator {
-        .frequency = MY_FREQUENCY,
-        .source = TIME_SOURCE_MMIO32,
-        .shift = 8,             /* scaling for higher accuracy */
-        .drift = -1,            /* Unknown drift */
-        .jitter = 0             /* time source is stable */
-};
-
-void time_init(void)
-{
-        ....
-        /* Initialization of the timer *.
-        my_interpolator.address = &my_timer;
-        register_time_interpolator(&my_interpolator);
-        ....
-}
-
-For more details see include/linux/timex.h and kernel/timer.c.
-
-Christoph Lameter <christoph@lameter.com>, October 31, 2004
-
diff --git a/include/linux/timex.h b/include/linux/timex.h
index da929dbbea2a..37ac3ff90faf 100644
--- a/include/linux/timex.h
+++ b/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
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