Merge branch 'driver-core-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[pandora-kernel.git] / kernel / time / clocksource.c

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 0e17c10..e0980f0 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -185,7 +185,6 @@ static struct clocksource *watchdog;
 static struct timer_list watchdog_timer;
 static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
 static DEFINE_SPINLOCK(watchdog_lock);
-static cycle_t watchdog_last;
 static int watchdog_running;
 
 static int clocksource_watchdog_kthread(void *data);
@@ -254,11 +253,6 @@ static void clocksource_watchdog(unsigned long data)
        if (!watchdog_running)
                goto out;
 
-       wdnow = watchdog->read(watchdog);
-       wd_nsec = clocksource_cyc2ns((wdnow - watchdog_last) & watchdog->mask,
-                                    watchdog->mult, watchdog->shift);
-       watchdog_last = wdnow;
-
        list_for_each_entry(cs, &watchdog_list, wd_list) {
 
                /* Clocksource already marked unstable? */
@@ -268,19 +262,28 @@ static void clocksource_watchdog(unsigned long data)
                        continue;
                }
 
+               local_irq_disable();
                csnow = cs->read(cs);
+               wdnow = watchdog->read(watchdog);
+               local_irq_enable();
 
                /* Clocksource initialized ? */
                if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
                        cs->flags |= CLOCK_SOURCE_WATCHDOG;
-                       cs->wd_last = csnow;
+                       cs->wd_last = wdnow;
+                       cs->cs_last = csnow;
                        continue;
                }
 
-               /* Check the deviation from the watchdog clocksource. */
-               cs_nsec = clocksource_cyc2ns((csnow - cs->wd_last) &
+               wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask,
+                                            watchdog->mult, watchdog->shift);
+
+               cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) &
                                             cs->mask, cs->mult, cs->shift);
-               cs->wd_last = csnow;
+               cs->cs_last = csnow;
+               cs->wd_last = wdnow;
+
+               /* Check the deviation from the watchdog clocksource. */
                if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
                        clocksource_unstable(cs, cs_nsec - wd_nsec);
                        continue;
@@ -318,7 +321,6 @@ static inline void clocksource_start_watchdog(void)
                return;
        init_timer(&watchdog_timer);
        watchdog_timer.function = clocksource_watchdog;
-       watchdog_last = watchdog->read(watchdog);
        watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
        add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
        watchdog_running = 1;
@@ -626,19 +628,6 @@ static void clocksource_enqueue(struct clocksource *cs)
        list_add(&cs->list, entry);
 }
 
-
-/*
- * Maximum time we expect to go between ticks. This includes idle
- * tickless time. It provides the trade off between selecting a
- * mult/shift pair that is very precise but can only handle a short
- * period of time, vs. a mult/shift pair that can handle long periods
- * of time but isn't as precise.
- *
- * This is a subsystem constant, and actual hardware limitations
- * may override it (ie: clocksources that wrap every 3 seconds).
- */
-#define MAX_UPDATE_LENGTH 5 /* Seconds */
-
 /**
  * __clocksource_updatefreq_scale - Used update clocksource with new freq
  * @t:         clocksource to be registered
@@ -652,15 +641,28 @@ static void clocksource_enqueue(struct clocksource *cs)
  */
 void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
 {
+       u64 sec;
+
        /*
-        * Ideally we want to use  some of the limits used in
-        * clocksource_max_deferment, to provide a more informed
-        * MAX_UPDATE_LENGTH. But for now this just gets the
-        * register interface working properly.
+        * Calc the maximum number of seconds which we can run before
+        * wrapping around. For clocksources which have a mask > 32bit
+        * we need to limit the max sleep time to have a good
+        * conversion precision. 10 minutes is still a reasonable
+        * amount. That results in a shift value of 24 for a
+        * clocksource with mask >= 40bit and f >= 4GHz. That maps to
+        * ~ 0.06ppm granularity for NTP. We apply the same 12.5%
+        * margin as we do in clocksource_max_deferment()
         */
+       sec = (cs->mask - (cs->mask >> 5));
+       do_div(sec, freq);
+       do_div(sec, scale);
+       if (!sec)
+               sec = 1;
+       else if (sec > 600 && cs->mask > UINT_MAX)
+               sec = 600;
+
        clocks_calc_mult_shift(&cs->mult, &cs->shift, freq,
-                                     NSEC_PER_SEC/scale,
-                                     MAX_UPDATE_LENGTH*scale);
+                              NSEC_PER_SEC / scale, sec * scale);
        cs->max_idle_ns = clocksource_max_deferment(cs);
 }
 EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);