1 files changed, 68 insertions, 2 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index d7395fdfb9f3..e4c699dfa4e8 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -18,7 +18,6 @@
 #include <linux/notifier.h>
 #include <linux/smp.h>
 #include <linux/sysdev.h>
-#include <linux/tick.h>
 
 #include "tick-internal.h"
 
@@ -183,7 +182,10 @@ void clockevents_register_device(struct clock_event_device *dev)
         unsigned long flags;
 
         BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
-        BUG_ON(!dev->cpumask);
+        if (!dev->cpumask) {
+                WARN_ON(num_possible_cpus() > 1);
+                dev->cpumask = cpumask_of(smp_processor_id());
+        }
 
         raw_spin_lock_irqsave(&clockevents_lock, flags);
 
@@ -195,6 +197,70 @@ 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
  */