3 files changed, 27 insertions, 37 deletions

diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c
index ebcf006406f9..95587b6c0259 100644
--- a/arch/arm/plat-omap/common.c
+++ b/arch/arm/plat-omap/common.c
@@ -253,11 +253,8 @@ static struct clocksource clocksource_32k = {
  */
 unsigned long long sched_clock(void)
 {
-        unsigned long long ret;
-
-        ret = (unsigned long long)clocksource_32k.read(&clocksource_32k);
-        ret = (ret * clocksource_32k.mult_orig) >> clocksource_32k.shift;
-        return ret;
+        return clocksource_cyc2ns(clocksource_32k.read(&clocksource_32k),
+                                  clocksource_32k.mult, clocksource_32k.shift);
 }
 
 static int __init omap_init_clocksource_32k(void)
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index e12e3095e2fb..e34015effeb6 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -149,8 +149,7 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
  * @disable:            optional function to disable the clocksource
  * @mask:               bitmask for two's complement
  *                      subtraction of non 64 bit counters
- * @mult:               cycle to nanosecond multiplier (adjusted by NTP)
- * @mult_orig:          cycle to nanosecond multiplier (unadjusted by NTP)
+ * @mult:               cycle to nanosecond multiplier
  * @shift:              cycle to nanosecond divisor (power of two)
  * @flags:              flags describing special properties
  * @vread:              vsyscall based read
@@ -168,7 +167,6 @@ struct clocksource {
         void (*disable)(struct clocksource *cs);
         cycle_t mask;
         u32 mult;
-        u32 mult_orig;
         u32 shift;
         unsigned long flags;
         cycle_t (*vread)(void);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index dfdab1cefe1e..f4056f6c2632 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -41,6 +41,8 @@ struct timekeeper {
         /* Shift conversion between clock shifted nano seconds and
          * ntp shifted nano seconds. */
         int     ntp_error_shift;
+        /* NTP adjusted clock multiplier */
+        u32     mult;
 };
 
 struct timekeeper timekeeper;
@@ -66,8 +68,8 @@ static void timekeeper_setup_internals(struct clocksource *clock)
         /* Do the ns -> cycle conversion first, using original mult */
         tmp = NTP_INTERVAL_LENGTH;
         tmp <<= clock->shift;
-        tmp += clock->mult_orig/2;
-        do_div(tmp, clock->mult_orig);
+        tmp += clock->mult/2;
+        do_div(tmp, clock->mult);
         if (tmp == 0)
                 tmp = 1;
 
@@ -77,13 +79,20 @@ static void timekeeper_setup_internals(struct clocksource *clock)
         /* Go back from cycles -> shifted ns */
         timekeeper.xtime_interval = (u64) interval * clock->mult;
         timekeeper.raw_interval =
-                ((u64) interval * clock->mult_orig) >> clock->shift;
+                ((u64) interval * clock->mult) >> clock->shift;
 
         timekeeper.xtime_nsec = 0;
         timekeeper.shift = clock->shift;
 
         timekeeper.ntp_error = 0;
         timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+
+        /*
+         * The timekeeper keeps its own mult values for the currently
+         * active clocksource. These value will be adjusted via NTP
+         * to counteract clock drifting.
+         */
+        timekeeper.mult = clock->mult;
 }
 
 /*
@@ -154,14 +163,15 @@ static void timekeeping_forward_now(void)
         cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
         clock->cycle_last = cycle_now;
 
-        nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+        nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+                                  timekeeper.shift);
 
         /* If arch requires, add in gettimeoffset() */
         nsec += arch_gettimeoffset();
 
         timespec_add_ns(&xtime, nsec);
 
-        nsec = clocksource_cyc2ns(cycle_delta, clock->mult_orig, clock->shift);
+        nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
         timespec_add_ns(&raw_time, nsec);
 }
 
@@ -193,8 +203,8 @@ void getnstimeofday(struct timespec *ts)
                 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
 
                 /* convert to nanoseconds: */
-                nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
-                                           clock->shift);
+                nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+                                           timekeeper.shift);
 
                 /* If arch requires, add in gettimeoffset() */
                 nsecs += arch_gettimeoffset();
@@ -228,8 +238,8 @@ ktime_t ktime_get(void)
                 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
 
                 /* convert to nanoseconds: */
-                nsecs += clocksource_cyc2ns(cycle_delta, clock->mult,
-                                            clock->shift);
+                nsecs += clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+                                            timekeeper.shift);
 
         } while (read_seqretry(&xtime_lock, seq));
         /*
@@ -271,8 +281,8 @@ void ktime_get_ts(struct timespec *ts)
                 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
 
                 /* convert to nanoseconds: */
-                nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
-                                           clock->shift);
+                nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+                                           timekeeper.shift);
 
         } while (read_seqretry(&xtime_lock, seq));
 
@@ -356,22 +366,10 @@ static void change_clocksource(void)
 
         if (new->enable && !new->enable(new))
                 return;
-        /*
-         * The frequency may have changed while the clocksource
-         * was disabled. If so the code in ->enable() must update
-         * the mult value to reflect the new frequency. Make sure
-         * mult_orig follows this change.
-         */
-        new->mult_orig = new->mult;
 
         old = timekeeper.clock;
         timekeeper_setup_internals(new);
 
-        /*
-         * Save mult_orig in mult so that the value can be restored
-         * regardless if ->enable() updates the value of mult or not.
-         */
-        old->mult = old->mult_orig;
         if (old->disable)
                 old->disable(old);
 
@@ -461,7 +459,7 @@ void getrawmonotonic(struct timespec *ts)
                 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
 
                 /* convert to nanoseconds: */
-                nsecs = clocksource_cyc2ns(cycle_delta, clock->mult_orig,
+                nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
                                            clock->shift);
 
                 *ts = raw_time;
@@ -521,9 +519,6 @@ void __init timekeeping_init(void)
         clock = clocksource_default_clock();
         if (clock->enable)
                 clock->enable(clock);
-        /* set mult_orig on enable */
-        clock->mult_orig = clock->mult;
-
         timekeeper_setup_internals(clock);
 
         xtime.tv_sec = sec;
@@ -697,7 +692,7 @@ static void timekeeping_adjust(s64 offset)
         } else
                 return;
 
-        timekeeper.clock->mult += adj;
+        timekeeper.mult += adj;
         timekeeper.xtime_interval += interval;
         timekeeper.xtime_nsec -= offset;
         timekeeper.ntp_error -= (interval - offset) <<
@@ -789,7 +784,7 @@ void update_wall_time(void)
         timekeeper.ntp_error += timekeeper.xtime_nsec <<
                                 timekeeper.ntp_error_shift;
 
-        nsecs = clocksource_cyc2ns(offset, clock->mult, clock->shift);
+        nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
         update_xtime_cache(nsecs);
 
         /* check to see if there is a new clocksource to use */