/**
* 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.
*/
void tick_broadcast_control(enum tick_broadcast_mode mode)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
int cpu, bc_stopped;
td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
/*
* Is the device not affected by the powerstate ?
*/
if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
return;
if (!tick_device_is_functional(dev))
return;
raw_spin_lock(&tick_broadcast_lock);
cpu = smp_processor_id();
bc = tick_broadcast_device.evtdev;
bc_stopped = cpumask_empty(tick_broadcast_mask);
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)
clockevents_shutdown(dev);
}
break;
case TICK_BROADCAST_OFF:
if (tick_broadcast_forced)
break;
cpumask_clear_cpu(cpu, tick_broadcast_on);
if (!tick_device_is_functional(dev))
break;
if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
}
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);
}
raw_spin_unlock(&tick_broadcast_lock);
}
/*
* Powerstate information: The system enters/leaves a state, where
* affected devices might stop
*/
static void tick_do_broadcast_on_off(unsigned long *reason)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags;
int cpu, bc_stopped;
spin_lock_irqsave(&tick_broadcast_lock, flags);
cpu = smp_processor_id();
td = &per_cpu(tick_cpu_device, cpu);
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;
if (!tick_device_is_functional(dev))
goto out;
bc_stopped = cpumask_empty(tick_get_broadcast_mask());
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
cpumask_set_cpu(cpu, tick_get_broadcast_mask());
if (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 &&
cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
}
break;
}
if (cpumask_empty(tick_get_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:
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
/*
* Setup the tick device
*/
static void tick_setup_device(struct tick_device *td,
struct clock_event_device *newdev, int cpu,
const struct cpumask *cpumask)
{
ktime_t next_event;
void (*handler)(struct clock_event_device *) = NULL;
/*
* First device setup ?
*/
if (!td->evtdev) {
/*
* If no cpu took the do_timer update, assign it to
* this cpu:
*/
if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
if (!tick_nohz_full_cpu(cpu))
tick_do_timer_cpu = cpu;
else
tick_do_timer_cpu = TICK_DO_TIMER_NONE;
tick_next_period = ktime_get();
tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
}
/*
* Startup in periodic mode first.
*/
td->mode = TICKDEV_MODE_PERIODIC;
} else {
handler = td->evtdev->event_handler;
next_event = td->evtdev->next_event;
td->evtdev->event_handler = clockevents_handle_noop;
}
td->evtdev = newdev;
/*
* When the device is not per cpu, pin the interrupt to the
* current cpu:
*/
if (!cpumask_equal(newdev->cpumask, cpumask))
irq_set_affinity(newdev->irq, cpumask);
/*
* When global broadcasting is active, check if the current
* device is registered as a placeholder for broadcast mode.
* This allows us to handle this x86 misfeature in a generic
* way. This function also returns !=0 when we keep the
* current active broadcast state for this CPU.
*/
if (tick_device_uses_broadcast(newdev, cpu))
return;
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(newdev, 0);
else
tick_setup_oneshot(newdev, handler, next_event);
}
/**
* tick_resume_local - Resume the local tick device
*
* Called from the local CPU for unfreeze or XEN resume magic.
*
* No locks required. Nothing can change the per cpu device.
*/
void tick_resume_local(void)
{
struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
bool broadcast = tick_resume_check_broadcast();
clockevents_tick_resume(td->evtdev);
if (!broadcast) {
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(td->evtdev, 0);
else
tick_resume_oneshot();
}
}
void tick_resume(void)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
int broadcast = tick_resume_broadcast();
clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
if (!broadcast) {
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(td->evtdev, 0);
else
tick_resume_oneshot();
}
}
/*
* Powerstate information: The system enters/leaves a state, where
* affected devices might stop
*/
static void tick_do_broadcast_on_off(void *why)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags, *reason = why;
int cpu;
spin_lock_irqsave(&tick_broadcast_lock, flags);
cpu = smp_processor_id();
td = &per_cpu(tick_cpu_device, cpu);
dev = td->evtdev;
bc = tick_broadcast_device.evtdev;
/*
* Is the device in broadcast mode forever or is it not
* affected by the powerstate ?
*/
if (!dev || !tick_device_is_functional(dev) ||
!(dev->features & CLOCK_EVT_FEAT_C3STOP))
goto out;
if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_ON) {
if (!cpu_isset(cpu, tick_broadcast_mask)) {
cpu_set(cpu, tick_broadcast_mask);
if (td->mode == TICKDEV_MODE_PERIODIC)
clockevents_set_mode(dev,
CLOCK_EVT_MODE_SHUTDOWN);
}
} else {
if (cpu_isset(cpu, tick_broadcast_mask)) {
cpu_clear(cpu, tick_broadcast_mask);
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
}
}
if (cpus_empty(tick_broadcast_mask))
clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
else {
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
tick_broadcast_setup_oneshot(bc);
}
out:
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
static void tick_resume(void)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
unsigned long flags;
int broadcast = tick_resume_broadcast();
raw_spin_lock_irqsave(&tick_device_lock, flags);
clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
if (!broadcast) {
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(td->evtdev, 0);
else
tick_resume_oneshot();
}
raw_spin_unlock_irqrestore(&tick_device_lock, flags);
}
/*
* Start the device in periodic mode
*/
static void tick_broadcast_start_periodic(struct clock_event_device *bc)
{
if (bc)
tick_setup_periodic(bc, 1);
}
/**
* 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.
*/
void tick_broadcast_control(enum tick_broadcast_mode mode)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
int cpu, bc_stopped;
unsigned long flags;
/* Protects also the local clockevent device. */
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
/*
* Is the device not affected by the powerstate ?
*/
if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
goto out;
if (!tick_device_is_functional(dev))
goto out;
cpu = smp_processor_id();
bc = tick_broadcast_device.evtdev;
bc_stopped = cpumask_empty(tick_broadcast_mask);
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)) {
/*
* 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);
}
break;
case TICK_BROADCAST_OFF:
if (tick_broadcast_forced)
break;
cpumask_clear_cpu(cpu, tick_broadcast_on);
if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
}
break;
}
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);
}
/*
* Start the device in periodic mode
*/
static void tick_broadcast_start_periodic(struct clock_event_device *bc)
{
if (bc && bc->mode == CLOCK_EVT_MODE_SHUTDOWN)
tick_setup_periodic(bc, 1);
}
/*
* Setup the tick device
*/
static void tick_setup_device(struct tick_device *td,
struct clock_event_device *newdev, int cpu,
const struct cpumask *cpumask)
{
void (*handler)(struct clock_event_device *) = NULL;
ktime_t next_event = 0;
/*
* First device setup ?
*/
if (!td->evtdev) {
/*
* If no cpu took the do_timer update, assign it to
* this cpu:
*/
if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
tick_do_timer_cpu = cpu;
tick_next_period = ktime_get();
tick_period = NSEC_PER_SEC / HZ;
#ifdef CONFIG_NO_HZ_FULL
/*
* The boot CPU may be nohz_full, in which case set
* tick_do_timer_boot_cpu so the first housekeeping
* secondary that comes up will take do_timer from
* us.
*/
if (tick_nohz_full_cpu(cpu))
tick_do_timer_boot_cpu = cpu;
} else if (tick_do_timer_boot_cpu != -1 &&
!tick_nohz_full_cpu(cpu)) {
tick_take_do_timer_from_boot();
tick_do_timer_boot_cpu = -1;
WARN_ON(tick_do_timer_cpu != cpu);
#endif
}
/*
* Startup in periodic mode first.
*/
td->mode = TICKDEV_MODE_PERIODIC;
} else {
handler = td->evtdev->event_handler;
next_event = td->evtdev->next_event;
td->evtdev->event_handler = clockevents_handle_noop;
}
td->evtdev = newdev;
/*
* When the device is not per cpu, pin the interrupt to the
* current cpu:
*/
if (!cpumask_equal(newdev->cpumask, cpumask))
irq_set_affinity(newdev->irq, cpumask);
/*
* When global broadcasting is active, check if the current
* device is registered as a placeholder for broadcast mode.
* This allows us to handle this x86 misfeature in a generic
* way. This function also returns !=0 when we keep the
* current active broadcast state for this CPU.
*/
if (tick_device_uses_broadcast(newdev, cpu))
return;
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(newdev, 0);
else
tick_setup_oneshot(newdev, handler, next_event);
}
