#include <linux/ktime.h>
#include <linux/hrtimer.h>
#include <linux/module.h>
+#include <linux/suspend.h>
+#include <linux/tick.h>
#include <trace/events/power.h>
#include "cpuidle.h"
off = 1;
}
-static int __cpuidle_register_device(struct cpuidle_device *dev);
+bool cpuidle_not_available(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
+{
+ return off || !initialized || !drv || !dev || !dev->enabled;
+}
/**
* cpuidle_play_dead - cpu off-lining
return -ENODEV;
/* Find lowest-power state that supports long-term idle */
- for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
+ for (i = drv->state_count - 1; i >= 0; i--)
if (drv->states[i].enter_dead)
return drv->states[i].enter_dead(dev, i);
return -ENODEV;
}
+static int find_deepest_state(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev,
+ unsigned int max_latency,
+ unsigned int forbidden_flags,
+ bool freeze)
+{
+ unsigned int latency_req = 0;
+ int i, ret = -ENXIO;
+
+ for (i = 0; i < drv->state_count; i++) {
+ struct cpuidle_state *s = &drv->states[i];
+ struct cpuidle_state_usage *su = &dev->states_usage[i];
+
+ if (s->disabled || su->disable || s->exit_latency <= latency_req
+ || s->exit_latency > max_latency
+ || (s->flags & forbidden_flags)
+ || (freeze && !s->enter_freeze))
+ continue;
+
+ latency_req = s->exit_latency;
+ ret = i;
+ }
+ return ret;
+}
+
+#ifdef CONFIG_SUSPEND
+/**
+ * cpuidle_find_deepest_state - Find the deepest available idle state.
+ * @drv: cpuidle driver for the given CPU.
+ * @dev: cpuidle device for the given CPU.
+ */
+int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
+{
+ return find_deepest_state(drv, dev, UINT_MAX, 0, false);
+}
+
+static void enter_freeze_proper(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev, int index)
+{
+ /*
+ * trace_suspend_resume() called by tick_freeze() for the last CPU
+ * executing it contains RCU usage regarded as invalid in the idle
+ * context, so tell RCU about that.
+ */
+ RCU_NONIDLE(tick_freeze());
+ /*
+ * The state used here cannot be a "coupled" one, because the "coupled"
+ * cpuidle mechanism enables interrupts and doing that with timekeeping
+ * suspended is generally unsafe.
+ */
+ stop_critical_timings();
+ drv->states[index].enter_freeze(dev, drv, index);
+ WARN_ON(!irqs_disabled());
+ /*
+ * timekeeping_resume() that will be called by tick_unfreeze() for the
+ * first CPU executing it calls functions containing RCU read-side
+ * critical sections, so tell RCU about that.
+ */
+ RCU_NONIDLE(tick_unfreeze());
+ start_critical_timings();
+}
+
+/**
+ * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle.
+ * @drv: cpuidle driver for the given CPU.
+ * @dev: cpuidle device for the given CPU.
+ *
+ * If there are states with the ->enter_freeze callback, find the deepest of
+ * them and enter it with frozen tick.
+ */
+int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+{
+ int index;
+
+ /*
+ * Find the deepest state with ->enter_freeze present, which guarantees
+ * that interrupts won't be enabled when it exits and allows the tick to
+ * be frozen safely.
+ */
+ index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
+ if (index >= 0)
+ enter_freeze_proper(drv, dev, index);
+
+ return index;
+}
+#endif /* CONFIG_SUSPEND */
+
/**
* cpuidle_enter_state - enter the state and update stats
* @dev: cpuidle device for this cpu
* @drv: cpuidle driver for this cpu
- * @next_state: index into drv->states of the state to enter
+ * @index: index into the states table in @drv of the state to enter
*/
int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
int index)
int entered_state;
struct cpuidle_state *target_state = &drv->states[index];
+ bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
ktime_t time_start, time_end;
s64 diff;
+ /*
+ * Tell the time framework to switch to a broadcast timer because our
+ * local timer will be shut down. If a local timer is used from another
+ * CPU as a broadcast timer, this call may fail if it is not available.
+ */
+ if (broadcast && tick_broadcast_enter()) {
+ index = find_deepest_state(drv, dev, target_state->exit_latency,
+ CPUIDLE_FLAG_TIMER_STOP, false);
+ if (index < 0) {
+ default_idle_call();
+ return -EBUSY;
+ }
+ target_state = &drv->states[index];
+ }
+
+ /* Take note of the planned idle state. */
+ sched_idle_set_state(target_state, index);
+
+ trace_cpu_idle_rcuidle(index, dev->cpu);
time_start = ktime_get();
+ stop_critical_timings();
entered_state = target_state->enter(dev, drv, index);
+ start_critical_timings();
time_end = ktime_get();
+ trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
+
+ /* The cpu is no longer idle or about to enter idle. */
+ sched_idle_set_state(NULL, -1);
+
+ if (broadcast) {
+ if (WARN_ON_ONCE(!irqs_disabled()))
+ local_irq_disable();
+
+ tick_broadcast_exit();
+ }
- local_irq_enable();
+ if (!cpuidle_state_is_coupled(drv, index))
+ local_irq_enable();
diff = ktime_to_us(ktime_sub(time_end, time_start));
if (diff > INT_MAX)
}
/**
- * cpuidle_idle_call - the main idle loop
+ * cpuidle_select - ask the cpuidle framework to choose an idle state
+ *
+ * @drv: the cpuidle driver
+ * @dev: the cpuidle device
*
- * NOTE: no locks or semaphores should be used here
- * return non-zero on failure
+ * Returns the index of the idle state.
*/
-int cpuidle_idle_call(void)
+int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
- struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
- struct cpuidle_driver *drv;
- int next_state, entered_state;
-
- if (off)
- return -ENODEV;
-
- if (!initialized)
- return -ENODEV;
-
- /* check if the device is ready */
- if (!dev || !dev->enabled)
- return -EBUSY;
-
- drv = cpuidle_get_cpu_driver(dev);
-
- /* ask the governor for the next state */
- next_state = cpuidle_curr_governor->select(drv, dev);
- if (next_state < 0)
- return -EBUSY;
-
- if (need_resched()) {
- dev->last_residency = 0;
- /* give the governor an opportunity to reflect on the outcome */
- if (cpuidle_curr_governor->reflect)
- cpuidle_curr_governor->reflect(dev, next_state);
- local_irq_enable();
- return 0;
- }
-
- trace_cpu_idle_rcuidle(next_state, dev->cpu);
-
- if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
- &dev->cpu);
-
- if (cpuidle_state_is_coupled(dev, drv, next_state))
- entered_state = cpuidle_enter_state_coupled(dev, drv,
- next_state);
- else
- entered_state = cpuidle_enter_state(dev, drv, next_state);
-
- if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
- &dev->cpu);
-
- trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
+ return cpuidle_curr_governor->select(drv, dev);
+}
- /* give the governor an opportunity to reflect on the outcome */
- if (cpuidle_curr_governor->reflect)
- cpuidle_curr_governor->reflect(dev, entered_state);
+/**
+ * cpuidle_enter - enter into the specified idle state
+ *
+ * @drv: the cpuidle driver tied with the cpu
+ * @dev: the cpuidle device
+ * @index: the index in the idle state table
+ *
+ * Returns the index in the idle state, < 0 in case of error.
+ * The error code depends on the backend driver
+ */
+int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+ int index)
+{
+ if (cpuidle_state_is_coupled(drv, index))
+ return cpuidle_enter_state_coupled(dev, drv, index);
+ return cpuidle_enter_state(dev, drv, index);
+}
- return 0;
+/**
+ * cpuidle_reflect - tell the underlying governor what was the state
+ * we were in
+ *
+ * @dev : the cpuidle device
+ * @index: the index in the idle state table
+ *
+ */
+void cpuidle_reflect(struct cpuidle_device *dev, int index)
+{
+ if (cpuidle_curr_governor->reflect && index >= 0)
+ cpuidle_curr_governor->reflect(dev, index);
}
/**
{
if (enabled_devices) {
initialized = 0;
- kick_all_cpus_sync();
+ wake_up_all_idle_cpus();
}
+
+ /*
+ * Make sure external observers (such as the scheduler)
+ * are done looking at pointed idle states.
+ */
+ synchronize_rcu();
}
/**
mutex_unlock(&cpuidle_lock);
}
-#ifdef CONFIG_ARCH_HAS_CPU_RELAX
-static int poll_idle(struct cpuidle_device *dev,
- struct cpuidle_driver *drv, int index)
-{
- ktime_t t1, t2;
- s64 diff;
-
- t1 = ktime_get();
- local_irq_enable();
- while (!need_resched())
- cpu_relax();
-
- t2 = ktime_get();
- diff = ktime_to_us(ktime_sub(t2, t1));
- if (diff > INT_MAX)
- diff = INT_MAX;
-
- dev->last_residency = (int) diff;
-
- return index;
-}
-
-static void poll_idle_init(struct cpuidle_driver *drv)
-{
- struct cpuidle_state *state = &drv->states[0];
-
- snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
- snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
- state->exit_latency = 0;
- state->target_residency = 0;
- state->power_usage = -1;
- state->flags = 0;
- state->enter = poll_idle;
- state->disabled = false;
-}
-#else
-static void poll_idle_init(struct cpuidle_driver *drv) {}
-#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
-
/**
* cpuidle_enable_device - enables idle PM for a CPU
* @dev: the CPU
*/
int cpuidle_enable_device(struct cpuidle_device *dev)
{
- int ret, i;
+ int ret;
struct cpuidle_driver *drv;
if (!dev)
if (!drv || !cpuidle_curr_governor)
return -EIO;
- if (!dev->state_count)
- dev->state_count = drv->state_count;
-
- if (dev->registered == 0) {
- ret = __cpuidle_register_device(dev);
- if (ret)
- return ret;
- }
-
- poll_idle_init(drv);
+ if (!dev->registered)
+ return -EINVAL;
ret = cpuidle_add_device_sysfs(dev);
if (ret)
(ret = cpuidle_curr_governor->enable(drv, dev)))
goto fail_sysfs;
- for (i = 0; i < dev->state_count; i++) {
- dev->states_usage[i].usage = 0;
- dev->states_usage[i].time = 0;
- }
- dev->last_residency = 0;
-
smp_wmb();
dev->enabled = 1;
EXPORT_SYMBOL_GPL(cpuidle_disable_device);
+static void __cpuidle_unregister_device(struct cpuidle_device *dev)
+{
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
+ list_del(&dev->device_list);
+ per_cpu(cpuidle_devices, dev->cpu) = NULL;
+ module_put(drv->owner);
+
+ dev->registered = 0;
+}
+
+static void __cpuidle_device_init(struct cpuidle_device *dev)
+{
+ memset(dev->states_usage, 0, sizeof(dev->states_usage));
+ dev->last_residency = 0;
+}
+
/**
* __cpuidle_register_device - internal register function called before register
* and enable routines
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
- ret = cpuidle_add_sysfs(dev);
- if (ret)
- goto err_sysfs;
ret = cpuidle_coupled_register_device(dev);
if (ret)
- goto err_coupled;
-
- dev->registered = 1;
- return 0;
+ __cpuidle_unregister_device(dev);
+ else
+ dev->registered = 1;
-err_coupled:
- cpuidle_remove_sysfs(dev);
-err_sysfs:
- list_del(&dev->device_list);
- per_cpu(cpuidle_devices, dev->cpu) = NULL;
- module_put(drv->owner);
return ret;
}
*/
int cpuidle_register_device(struct cpuidle_device *dev)
{
- int ret;
+ int ret = -EBUSY;
if (!dev)
return -EINVAL;
mutex_lock(&cpuidle_lock);
- if ((ret = __cpuidle_register_device(dev))) {
- mutex_unlock(&cpuidle_lock);
- return ret;
- }
+ if (dev->registered)
+ goto out_unlock;
+
+ __cpuidle_device_init(dev);
+
+ ret = __cpuidle_register_device(dev);
+ if (ret)
+ goto out_unlock;
+
+ ret = cpuidle_add_sysfs(dev);
+ if (ret)
+ goto out_unregister;
+
+ ret = cpuidle_enable_device(dev);
+ if (ret)
+ goto out_sysfs;
- cpuidle_enable_device(dev);
cpuidle_install_idle_handler();
+out_unlock:
mutex_unlock(&cpuidle_lock);
- return 0;
+ return ret;
+out_sysfs:
+ cpuidle_remove_sysfs(dev);
+out_unregister:
+ __cpuidle_unregister_device(dev);
+ goto out_unlock;
}
EXPORT_SYMBOL_GPL(cpuidle_register_device);
*/
void cpuidle_unregister_device(struct cpuidle_device *dev)
{
- struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
-
- if (dev->registered == 0)
+ if (!dev || dev->registered == 0)
return;
cpuidle_pause_and_lock();
cpuidle_disable_device(dev);
cpuidle_remove_sysfs(dev);
- list_del(&dev->device_list);
- per_cpu(cpuidle_devices, dev->cpu) = NULL;
+
+ __cpuidle_unregister_device(dev);
cpuidle_coupled_unregister_device(dev);
cpuidle_resume_and_unlock();
-
- module_put(drv->owner);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
int cpu;
struct cpuidle_device *device;
- for_each_possible_cpu(cpu) {
+ for_each_cpu(cpu, drv->cpumask) {
device = &per_cpu(cpuidle_dev, cpu);
cpuidle_unregister_device(device);
}
return ret;
}
- for_each_possible_cpu(cpu) {
+ for_each_cpu(cpu, drv->cpumask) {
device = &per_cpu(cpuidle_dev, cpu);
device->cpu = cpu;
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
/*
- * On multiplatform for ARM, the coupled idle states could
+ * On multiplatform for ARM, the coupled idle states could be
* enabled in the kernel even if the cpuidle driver does not
* use it. Note, coupled_cpus is a struct copy.
*/
#ifdef CONFIG_SMP
-static void smp_callback(void *v)
-{
- /* we already woke the CPU up, nothing more to do */
-}
-
/*
* This function gets called when a part of the kernel has a new latency
* requirement. This means we need to get all processors out of their C-state,
static int cpuidle_latency_notify(struct notifier_block *b,
unsigned long l, void *v)
{
- smp_call_function(smp_callback, NULL, 1);
+ wake_up_all_idle_cpus();
return NOTIFY_OK;
}
projects / firefly-linux-kernel-4.4.55.git / blobdiff