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authorThomas Gleixner <tglx@linutronix.de>2011-05-20 20:06:24 +0200
committerThomas Gleixner <tglx@linutronix.de>2011-05-20 20:08:05 +0200
commit250f972d85effad5b6e10da4bbd877e6a4b503b6 (patch)
tree007393a6fc6439af7e0121dd99a6f9f9fb8405bc /kernel/time
parent7372b0b122af0f6675f3ab65bfd91c8a438e0480 (diff)
parentbbe7b8bef48c567f5ff3f6041c1fb011292e8f12 (diff)
downloadlinux-250f972d85effad5b6e10da4bbd877e6a4b503b6.tar.bz2
Merge branch 'timers/urgent' into timers/core
Reason: Get upstream fixes and kfree_rcu which is necessary for a follow up patch. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clockevents.c64
-rw-r--r--kernel/time/clocksource.c42
-rw-r--r--kernel/time/tick-broadcast.c12
3 files changed, 96 insertions, 22 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 0d74b9ba90c8..c027d4f602f1 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -194,6 +194,70 @@ void clockevents_register_device(struct clock_event_device *dev)
}
EXPORT_SYMBOL_GPL(clockevents_register_device);
+static void clockevents_config(struct clock_event_device *dev,
+ u32 freq)
+{
+ u64 sec;
+
+ if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+ return;
+
+ /*
+ * Calculate the maximum number of seconds we can sleep. Limit
+ * to 10 minutes for hardware which can program more than
+ * 32bit ticks so we still get reasonable conversion values.
+ */
+ sec = dev->max_delta_ticks;
+ do_div(sec, freq);
+ if (!sec)
+ sec = 1;
+ else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
+ sec = 600;
+
+ clockevents_calc_mult_shift(dev, freq, sec);
+ dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
+ dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
+}
+
+/**
+ * clockevents_config_and_register - Configure and register a clock event device
+ * @dev: device to register
+ * @freq: The clock frequency
+ * @min_delta: The minimum clock ticks to program in oneshot mode
+ * @max_delta: The maximum clock ticks to program in oneshot mode
+ *
+ * min/max_delta can be 0 for devices which do not support oneshot mode.
+ */
+void clockevents_config_and_register(struct clock_event_device *dev,
+ u32 freq, unsigned long min_delta,
+ unsigned long max_delta)
+{
+ dev->min_delta_ticks = min_delta;
+ dev->max_delta_ticks = max_delta;
+ clockevents_config(dev, freq);
+ clockevents_register_device(dev);
+}
+
+/**
+ * clockevents_update_freq - Update frequency and reprogram a clock event device.
+ * @dev: device to modify
+ * @freq: new device frequency
+ *
+ * Reconfigure and reprogram a clock event device in oneshot
+ * mode. Must be called on the cpu for which the device delivers per
+ * cpu timer events with interrupts disabled! Returns 0 on success,
+ * -ETIME when the event is in the past.
+ */
+int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
+{
+ clockevents_config(dev, freq);
+
+ if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
+ return 0;
+
+ return clockevents_program_event(dev, dev->next_event, ktime_get());
+}
+
/*
* Noop handler when we shut down an event device
*/
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 6519cf62d9cd..1c95fd677328 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -626,19 +626,6 @@ 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 +639,28 @@ 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);
@@ -685,8 +685,8 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
/* Add clocksource to the clcoksource list */
mutex_lock(&clocksource_mutex);
clocksource_enqueue(cs);
- clocksource_select();
clocksource_enqueue_watchdog(cs);
+ clocksource_select();
mutex_unlock(&clocksource_mutex);
return 0;
}
@@ -706,8 +706,8 @@ int clocksource_register(struct clocksource *cs)
mutex_lock(&clocksource_mutex);
clocksource_enqueue(cs);
- clocksource_select();
clocksource_enqueue_watchdog(cs);
+ clocksource_select();
mutex_unlock(&clocksource_mutex);
return 0;
}
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 827e0f862da4..c7218d132738 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -524,10 +524,11 @@ static void tick_broadcast_init_next_event(struct cpumask *mask,
*/
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
+ int cpu = smp_processor_id();
+
/* Set it up only once ! */
if (bc->event_handler != tick_handle_oneshot_broadcast) {
int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
- int cpu = smp_processor_id();
bc->event_handler = tick_handle_oneshot_broadcast;
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
@@ -553,6 +554,15 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
tick_broadcast_set_event(tick_next_period, 1);
} else
bc->next_event.tv64 = KTIME_MAX;
+ } else {
+ /*
+ * The first cpu which switches to oneshot mode sets
+ * the bit for all other cpus which are in the general
+ * (periodic) broadcast mask. So the bit is set and
+ * would prevent the first broadcast enter after this
+ * to program the bc device.
+ */
+ tick_broadcast_clear_oneshot(cpu);
}
}