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-rw-r--r--kernel/time/tick-broadcast.c392
1 files changed, 223 insertions, 169 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 066f0ec05e48..f6aae7977824 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -33,12 +33,14 @@ static cpumask_var_t tick_broadcast_mask;
static cpumask_var_t tick_broadcast_on;
static cpumask_var_t tmpmask;
static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
-static int tick_broadcast_force;
+static int tick_broadcast_forced;
#ifdef CONFIG_TICK_ONESHOT
static void tick_broadcast_clear_oneshot(int cpu);
+static void tick_resume_broadcast_oneshot(struct clock_event_device *bc);
#else
static inline void tick_broadcast_clear_oneshot(int cpu) { }
+static inline void tick_resume_broadcast_oneshot(struct clock_event_device *bc) { }
#endif
/*
@@ -157,7 +159,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
{
struct clock_event_device *bc = tick_broadcast_device.evtdev;
unsigned long flags;
- int ret;
+ int ret = 0;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -219,13 +221,14 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
* If we kept the cpu in the broadcast mask,
* tell the caller to leave the per cpu device
* in shutdown state. The periodic interrupt
- * is delivered by the broadcast device.
+ * is delivered by the broadcast device, if
+ * the broadcast device exists and is not
+ * hrtimer based.
*/
- ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+ ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
break;
default:
- /* Nothing to do */
- ret = 0;
break;
}
}
@@ -253,18 +256,32 @@ int tick_receive_broadcast(void)
/*
* Broadcast the event to the cpus, which are set in the mask (mangled).
*/
-static void tick_do_broadcast(struct cpumask *mask)
+static bool tick_do_broadcast(struct cpumask *mask)
{
int cpu = smp_processor_id();
struct tick_device *td;
+ bool local = false;
/*
* Check, if the current cpu is in the mask
*/
if (cpumask_test_cpu(cpu, mask)) {
+ struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
cpumask_clear_cpu(cpu, mask);
- td = &per_cpu(tick_cpu_device, cpu);
- td->evtdev->event_handler(td->evtdev);
+ /*
+ * We only run the local handler, if the broadcast
+ * device is not hrtimer based. Otherwise we run into
+ * a hrtimer recursion.
+ *
+ * local timer_interrupt()
+ * local_handler()
+ * expire_hrtimers()
+ * bc_handler()
+ * local_handler()
+ * expire_hrtimers()
+ */
+ local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);
}
if (!cpumask_empty(mask)) {
@@ -277,16 +294,17 @@ static void tick_do_broadcast(struct cpumask *mask)
td = &per_cpu(tick_cpu_device, cpumask_first(mask));
td->evtdev->broadcast(mask);
}
+ return local;
}
/*
* Periodic broadcast:
* - invoke the broadcast handlers
*/
-static void tick_do_periodic_broadcast(void)
+static bool tick_do_periodic_broadcast(void)
{
cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask);
- tick_do_broadcast(tmpmask);
+ return tick_do_broadcast(tmpmask);
}
/*
@@ -294,79 +312,91 @@ static void tick_do_periodic_broadcast(void)
*/
static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
{
- ktime_t next;
+ struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+ bool bc_local;
raw_spin_lock(&tick_broadcast_lock);
- tick_do_periodic_broadcast();
+ /* Handle spurious interrupts gracefully */
+ if (clockevent_state_shutdown(tick_broadcast_device.evtdev)) {
+ raw_spin_unlock(&tick_broadcast_lock);
+ return;
+ }
- /*
- * The device is in periodic mode. No reprogramming necessary:
- */
- if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
- goto unlock;
+ bc_local = tick_do_periodic_broadcast();
- /*
- * Setup the next period for devices, which do not have
- * periodic mode. We read dev->next_event first and add to it
- * when the event already expired. clockevents_program_event()
- * sets dev->next_event only when the event is really
- * programmed to the device.
- */
- for (next = dev->next_event; ;) {
- next = ktime_add(next, tick_period);
+ if (clockevent_state_oneshot(dev)) {
+ ktime_t next = ktime_add(dev->next_event, tick_period);
- if (!clockevents_program_event(dev, next, false))
- goto unlock;
- tick_do_periodic_broadcast();
+ clockevents_program_event(dev, next, true);
}
-unlock:
raw_spin_unlock(&tick_broadcast_lock);
+
+ /*
+ * We run the handler of the local cpu after dropping
+ * tick_broadcast_lock because the handler might deadlock when
+ * trying to switch to oneshot mode.
+ */
+ if (bc_local)
+ td->evtdev->event_handler(td->evtdev);
}
-/*
- * Powerstate information: The system enters/leaves a state, where
- * affected devices might stop
+/**
+ * tick_broadcast_control - Enable/disable or force broadcast mode
+ * @mode: The selected broadcast mode
+ *
+ * Called when the system enters a state where affected tick devices
+ * might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
+ *
+ * Called with interrupts disabled, so clockevents_lock is not
+ * required here because the local clock event device cannot go away
+ * under us.
*/
-static void tick_do_broadcast_on_off(unsigned long *reason)
+void tick_broadcast_control(enum tick_broadcast_mode mode)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
- unsigned long flags;
int cpu, bc_stopped;
- raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
-
- cpu = smp_processor_id();
- td = &per_cpu(tick_cpu_device, cpu);
+ td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
- bc = tick_broadcast_device.evtdev;
/*
* Is the device not affected by the powerstate ?
*/
if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
- goto out;
+ return;
if (!tick_device_is_functional(dev))
- goto out;
+ return;
+ raw_spin_lock(&tick_broadcast_lock);
+ cpu = smp_processor_id();
+ bc = tick_broadcast_device.evtdev;
bc_stopped = cpumask_empty(tick_broadcast_mask);
- switch (*reason) {
- case CLOCK_EVT_NOTIFY_BROADCAST_ON:
- case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
+ switch (mode) {
+ case TICK_BROADCAST_FORCE:
+ tick_broadcast_forced = 1;
+ case TICK_BROADCAST_ON:
cpumask_set_cpu(cpu, tick_broadcast_on);
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
- if (tick_broadcast_device.mode ==
- TICKDEV_MODE_PERIODIC)
+ /*
+ * Only shutdown the cpu local device, if:
+ *
+ * - the broadcast device exists
+ * - the broadcast device is not a hrtimer based one
+ * - the broadcast device is in periodic mode to
+ * avoid a hickup during switch to oneshot mode
+ */
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&
+ tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
clockevents_shutdown(dev);
}
- if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
- tick_broadcast_force = 1;
break;
- case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
- if (tick_broadcast_force)
+
+ case TICK_BROADCAST_OFF:
+ if (tick_broadcast_forced)
break;
cpumask_clear_cpu(cpu, tick_broadcast_on);
if (!tick_device_is_functional(dev))
@@ -379,31 +409,20 @@ static void tick_do_broadcast_on_off(unsigned long *reason)
break;
}
- if (cpumask_empty(tick_broadcast_mask)) {
- if (!bc_stopped)
- clockevents_shutdown(bc);
- } else if (bc_stopped) {
- if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
- tick_broadcast_start_periodic(bc);
- else
- tick_broadcast_setup_oneshot(bc);
+ if (bc) {
+ if (cpumask_empty(tick_broadcast_mask)) {
+ if (!bc_stopped)
+ clockevents_shutdown(bc);
+ } else if (bc_stopped) {
+ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+ tick_broadcast_start_periodic(bc);
+ else
+ tick_broadcast_setup_oneshot(bc);
+ }
}
-out:
- raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
-}
-
-/*
- * Powerstate information: The system enters/leaves a state, where
- * affected devices might stop.
- */
-void tick_broadcast_on_off(unsigned long reason, int *oncpu)
-{
- if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
- printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
- "offline CPU #%d\n", *oncpu);
- else
- tick_do_broadcast_on_off(&reason);
+ raw_spin_unlock(&tick_broadcast_lock);
}
+EXPORT_SYMBOL_GPL(tick_broadcast_control);
/*
* Set the periodic handler depending on broadcast on/off
@@ -416,14 +435,14 @@ void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
dev->event_handler = tick_handle_periodic_broadcast;
}
+#ifdef CONFIG_HOTPLUG_CPU
/*
* Remove a CPU from broadcasting
*/
-void tick_shutdown_broadcast(unsigned int *cpup)
+void tick_shutdown_broadcast(unsigned int cpu)
{
struct clock_event_device *bc;
unsigned long flags;
- unsigned int cpu = *cpup;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -438,6 +457,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
+#endif
void tick_suspend_broadcast(void)
{
@@ -453,38 +473,48 @@ void tick_suspend_broadcast(void)
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
-int tick_resume_broadcast(void)
+/*
+ * This is called from tick_resume_local() on a resuming CPU. That's
+ * called from the core resume function, tick_unfreeze() and the magic XEN
+ * resume hackery.
+ *
+ * In none of these cases the broadcast device mode can change and the
+ * bit of the resuming CPU in the broadcast mask is safe as well.
+ */
+bool tick_resume_check_broadcast(void)
+{
+ if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT)
+ return false;
+ else
+ return cpumask_test_cpu(smp_processor_id(), tick_broadcast_mask);
+}
+
+void tick_resume_broadcast(void)
{
struct clock_event_device *bc;
unsigned long flags;
- int broadcast = 0;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
bc = tick_broadcast_device.evtdev;
if (bc) {
- clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
+ clockevents_tick_resume(bc);
switch (tick_broadcast_device.mode) {
case TICKDEV_MODE_PERIODIC:
if (!cpumask_empty(tick_broadcast_mask))
tick_broadcast_start_periodic(bc);
- broadcast = cpumask_test_cpu(smp_processor_id(),
- tick_broadcast_mask);
break;
case TICKDEV_MODE_ONESHOT:
if (!cpumask_empty(tick_broadcast_mask))
- broadcast = tick_resume_broadcast_oneshot(bc);
+ tick_resume_broadcast_oneshot(bc);
break;
}
}
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
-
- return broadcast;
}
-
#ifdef CONFIG_TICK_ONESHOT
static cpumask_var_t tick_broadcast_oneshot_mask;
@@ -527,24 +557,19 @@ static void tick_broadcast_set_affinity(struct clock_event_device *bc,
irq_set_affinity(bc->irq, bc->cpumask);
}
-static int tick_broadcast_set_event(struct clock_event_device *bc, int cpu,
- ktime_t expires, int force)
+static void tick_broadcast_set_event(struct clock_event_device *bc, int cpu,
+ ktime_t expires)
{
- int ret;
-
- if (bc->mode != CLOCK_EVT_MODE_ONESHOT)
- clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+ if (!clockevent_state_oneshot(bc))
+ clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
- ret = clockevents_program_event(bc, expires, force);
- if (!ret)
- tick_broadcast_set_affinity(bc, cpumask_of(cpu));
- return ret;
+ clockevents_program_event(bc, expires, 1);
+ tick_broadcast_set_affinity(bc, cpumask_of(cpu));
}
-int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
+static void tick_resume_broadcast_oneshot(struct clock_event_device *bc)
{
- clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
- return 0;
+ clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
}
/*
@@ -562,8 +587,8 @@ void tick_check_oneshot_broadcast_this_cpu(void)
* switched over, leave the device alone.
*/
if (td->mode == TICKDEV_MODE_ONESHOT) {
- clockevents_set_mode(td->evtdev,
- CLOCK_EVT_MODE_ONESHOT);
+ clockevents_switch_state(td->evtdev,
+ CLOCK_EVT_STATE_ONESHOT);
}
}
}
@@ -576,9 +601,9 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
struct tick_device *td;
ktime_t now, next_event;
int cpu, next_cpu = 0;
+ bool bc_local;
raw_spin_lock(&tick_broadcast_lock);
-again:
dev->next_event.tv64 = KTIME_MAX;
next_event.tv64 = KTIME_MAX;
cpumask_clear(tmpmask);
@@ -620,7 +645,7 @@ again:
/*
* Wakeup the cpus which have an expired event.
*/
- tick_do_broadcast(tmpmask);
+ bc_local = tick_do_broadcast(tmpmask);
/*
* Two reasons for reprogram:
@@ -632,15 +657,15 @@ again:
* - There are pending events on sleeping CPUs which were not
* in the event mask
*/
- if (next_event.tv64 != KTIME_MAX) {
- /*
- * Rearm the broadcast device. If event expired,
- * repeat the above
- */
- if (tick_broadcast_set_event(dev, next_cpu, next_event, 0))
- goto again;
- }
+ if (next_event.tv64 != KTIME_MAX)
+ tick_broadcast_set_event(dev, next_cpu, next_event);
+
raw_spin_unlock(&tick_broadcast_lock);
+
+ if (bc_local) {
+ td = this_cpu_ptr(&tick_cpu_device);
+ td->evtdev->event_handler(td->evtdev);
+ }
}
static int broadcast_needs_cpu(struct clock_event_device *bc, int cpu)
@@ -666,82 +691,88 @@ static void broadcast_shutdown_local(struct clock_event_device *bc,
if (dev->next_event.tv64 < bc->next_event.tv64)
return;
}
- clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
-}
-
-static void broadcast_move_bc(int deadcpu)
-{
- struct clock_event_device *bc = tick_broadcast_device.evtdev;
-
- if (!bc || !broadcast_needs_cpu(bc, deadcpu))
- return;
- /* This moves the broadcast assignment to this cpu */
- clockevents_program_event(bc, bc->next_event, 1);
+ clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
}
-/*
- * Powerstate information: The system enters/leaves a state, where
- * affected devices might stop
- * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
- */
-int tick_broadcast_oneshot_control(unsigned long reason)
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
{
struct clock_event_device *bc, *dev;
- struct tick_device *td;
- unsigned long flags;
- ktime_t now;
int cpu, ret = 0;
+ ktime_t now;
/*
- * Periodic mode does not care about the enter/exit of power
- * states
+ * If there is no broadcast device, tell the caller not to go
+ * into deep idle.
*/
- if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
- return 0;
+ if (!tick_broadcast_device.evtdev)
+ return -EBUSY;
- /*
- * We are called with preemtion disabled from the depth of the
- * idle code, so we can't be moved away.
- */
+ dev = this_cpu_ptr(&tick_cpu_device)->evtdev;
+
+ raw_spin_lock(&tick_broadcast_lock);
+ bc = tick_broadcast_device.evtdev;
cpu = smp_processor_id();
- td = &per_cpu(tick_cpu_device, cpu);
- dev = td->evtdev;
- if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
- return 0;
+ if (state == TICK_BROADCAST_ENTER) {
+ /*
+ * If the current CPU owns the hrtimer broadcast
+ * mechanism, it cannot go deep idle and we do not add
+ * the CPU to the broadcast mask. We don't have to go
+ * through the EXIT path as the local timer is not
+ * shutdown.
+ */
+ ret = broadcast_needs_cpu(bc, cpu);
+ if (ret)
+ goto out;
- bc = tick_broadcast_device.evtdev;
+ /*
+ * If the broadcast device is in periodic mode, we
+ * return.
+ */
+ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
+ /* If it is a hrtimer based broadcast, return busy */
+ if (bc->features & CLOCK_EVT_FEAT_HRTIMER)
+ ret = -EBUSY;
+ goto out;
+ }
- raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
- if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
+
+ /* Conditionally shut down the local timer. */
broadcast_shutdown_local(bc, dev);
+
/*
* We only reprogram the broadcast timer if we
* did not mark ourself in the force mask and
* if the cpu local event is earlier than the
* broadcast event. If the current CPU is in
* the force mask, then we are going to be
- * woken by the IPI right away.
+ * woken by the IPI right away; we return
+ * busy, so the CPU does not try to go deep
+ * idle.
*/
- if (!cpumask_test_cpu(cpu, tick_broadcast_force_mask) &&
- dev->next_event.tv64 < bc->next_event.tv64)
- tick_broadcast_set_event(bc, cpu, dev->next_event, 1);
+ if (cpumask_test_cpu(cpu, tick_broadcast_force_mask)) {
+ ret = -EBUSY;
+ } else if (dev->next_event.tv64 < bc->next_event.tv64) {
+ tick_broadcast_set_event(bc, cpu, dev->next_event);
+ /*
+ * In case of hrtimer broadcasts the
+ * programming might have moved the
+ * timer to this cpu. If yes, remove
+ * us from the broadcast mask and
+ * return busy.
+ */
+ ret = broadcast_needs_cpu(bc, cpu);
+ if (ret) {
+ cpumask_clear_cpu(cpu,
+ tick_broadcast_oneshot_mask);
+ }
+ }
}
- /*
- * If the current CPU owns the hrtimer broadcast
- * mechanism, it cannot go deep idle and we remove the
- * CPU from the broadcast mask. We don't have to go
- * through the EXIT path as the local timer is not
- * shutdown.
- */
- ret = broadcast_needs_cpu(bc, cpu);
- if (ret)
- cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
} else {
if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
- clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
+ clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
/*
* The cpu which was handling the broadcast
* timer marked this cpu in the broadcast
@@ -805,7 +836,7 @@ int tick_broadcast_oneshot_control(unsigned long reason)
}
}
out:
- raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+ raw_spin_unlock(&tick_broadcast_lock);
return ret;
}
@@ -842,7 +873,7 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
/* Set it up only once ! */
if (bc->event_handler != tick_handle_oneshot_broadcast) {
- int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+ int was_periodic = clockevent_state_periodic(bc);
bc->event_handler = tick_handle_oneshot_broadcast;
@@ -858,10 +889,10 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
tick_broadcast_oneshot_mask, tmpmask);
if (was_periodic && !cpumask_empty(tmpmask)) {
- clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+ clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
tick_broadcast_init_next_event(tmpmask,
tick_next_period);
- tick_broadcast_set_event(bc, cpu, tick_next_period, 1);
+ tick_broadcast_set_event(bc, cpu, tick_next_period);
} else
bc->next_event.tv64 = KTIME_MAX;
} else {
@@ -894,14 +925,28 @@ void tick_broadcast_switch_to_oneshot(void)
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
+#ifdef CONFIG_HOTPLUG_CPU
+void hotplug_cpu__broadcast_tick_pull(int deadcpu)
+{
+ struct clock_event_device *bc;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+ bc = tick_broadcast_device.evtdev;
+
+ if (bc && broadcast_needs_cpu(bc, deadcpu)) {
+ /* This moves the broadcast assignment to this CPU: */
+ clockevents_program_event(bc, bc->next_event, 1);
+ }
+ raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
/*
* Remove a dead CPU from broadcasting
*/
-void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
+void tick_shutdown_broadcast_oneshot(unsigned int cpu)
{
unsigned long flags;
- unsigned int cpu = *cpup;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -913,10 +958,9 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
cpumask_clear_cpu(cpu, tick_broadcast_force_mask);
- broadcast_move_bc(cpu);
-
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
+#endif
/*
* Check, whether the broadcast device is in one shot mode
@@ -936,6 +980,16 @@ bool tick_broadcast_oneshot_available(void)
return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
}
+#else
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+ struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+ if (!bc || (bc->features & CLOCK_EVT_FEAT_HRTIMER))
+ return -EBUSY;
+
+ return 0;
+}
#endif
void __init tick_broadcast_init(void)