--- /dev/null
+/*
+ * cpuidle.c - core cpuidle infrastructure
+ *
+ * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ * Shaohua Li <shaohua.li@intel.com>
+ * Adam Belay <abelay@novell.com>
+ *
+ * This code is licenced under the GPL.
+ */
+
+#include <linux/clockchips.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/notifier.h>
+#include <linux/pm_qos.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+#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"
+
+DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
+
+DEFINE_MUTEX(cpuidle_lock);
+LIST_HEAD(cpuidle_detected_devices);
+
+static int enabled_devices;
+static int off __read_mostly;
+static int initialized __read_mostly;
+
+int cpuidle_disabled(void)
+{
+ return off;
+}
+void disable_cpuidle(void)
+{
+ off = 1;
+}
+
+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
+ *
+ * Returns in case of an error or no driver
+ */
+int cpuidle_play_dead(void)
+{
+ struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+ int i;
+
+ if (!drv)
+ return -ENODEV;
+
+ /* Find lowest-power state that supports long-term idle */
+ for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; 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, bool freeze)
+{
+ unsigned int latency_req = 0;
+ int i, ret = freeze ? -1 : CPUIDLE_DRIVER_STATE_START - 1;
+
+ for (i = CPUIDLE_DRIVER_STATE_START; 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
+ || (freeze && !s->enter_freeze))
+ continue;
+
+ latency_req = s->exit_latency;
+ ret = i;
+ }
+ return ret;
+}
+
+/**
+ * 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, false);
+}
+
+static void enter_freeze_proper(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev, int index)
+{
+ 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.
+ */
+ drv->states[index].enter_freeze(dev, drv, index);
+ WARN_ON(!irqs_disabled());
+ /*
+ * timekeeping_resume() that will be called by tick_unfreeze() for the
+ * last CPU executing it calls functions containing RCU read-side
+ * critical sections, so tell RCU about that.
+ */
+ RCU_NONIDLE(tick_unfreeze());
+}
+
+/**
+ * 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, true);
+ if (index >= 0)
+ enter_freeze_proper(drv, dev, index);
+
+ return index;
+}
+
+/**
+ * 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
+ */
+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())
+ return -EBUSY;
+
+ trace_cpu_idle_rcuidle(index, dev->cpu);
+ time_start = ktime_get();
+
+ entered_state = target_state->enter(dev, drv, index);
+
+ time_end = ktime_get();
+ trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
+
+ if (broadcast) {
+ if (WARN_ON_ONCE(!irqs_disabled()))
+ local_irq_disable();
+
+ tick_broadcast_exit();
+ }
+
+ if (!cpuidle_state_is_coupled(dev, drv, entered_state))
+ local_irq_enable();
+
+ diff = ktime_to_us(ktime_sub(time_end, time_start));
+ if (diff > INT_MAX)
+ diff = INT_MAX;
+
+ dev->last_residency = (int) diff;
+
+ if (entered_state >= 0) {
+ /* Update cpuidle counters */
+ /* This can be moved to within driver enter routine
+ * but that results in multiple copies of same code.
+ */
+ dev->states_usage[entered_state].time += dev->last_residency;
+ dev->states_usage[entered_state].usage++;
+ } else {
+ dev->last_residency = 0;
+ }
+
+ return entered_state;
+}
+
+/**
+ * cpuidle_select - ask the cpuidle framework to choose an idle state
+ *
+ * @drv: the cpuidle driver
+ * @dev: the cpuidle device
+ *
+ * Returns the index of the idle state.
+ */
+int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+{
+ return cpuidle_curr_governor->select(drv, dev);
+}
+
+/**
+ * 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(dev, drv, index))
+ return cpuidle_enter_state_coupled(dev, drv, index);
+ return cpuidle_enter_state(dev, drv, index);
+}
+
+/**
+ * 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)
+ cpuidle_curr_governor->reflect(dev, index);
+}
+
+/**
+ * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
+ */
+void cpuidle_install_idle_handler(void)
+{
+ if (enabled_devices) {
+ /* Make sure all changes finished before we switch to new idle */
+ smp_wmb();
+ initialized = 1;
+ }
+}
+
+/**
+ * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
+ */
+void cpuidle_uninstall_idle_handler(void)
+{
+ if (enabled_devices) {
+ initialized = 0;
+ wake_up_all_idle_cpus();
+ }
+
+ /*
+ * Make sure external observers (such as the scheduler)
+ * are done looking at pointed idle states.
+ */
+ synchronize_rcu();
+}
+
+/**
+ * cpuidle_pause_and_lock - temporarily disables CPUIDLE
+ */
+void cpuidle_pause_and_lock(void)
+{
+ mutex_lock(&cpuidle_lock);
+ cpuidle_uninstall_idle_handler();
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
+
+/**
+ * cpuidle_resume_and_unlock - resumes CPUIDLE operation
+ */
+void cpuidle_resume_and_unlock(void)
+{
+ cpuidle_install_idle_handler();
+ mutex_unlock(&cpuidle_lock);
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
+
+/* Currently used in suspend/resume path to suspend cpuidle */
+void cpuidle_pause(void)
+{
+ mutex_lock(&cpuidle_lock);
+ cpuidle_uninstall_idle_handler();
+ mutex_unlock(&cpuidle_lock);
+}
+
+/* Currently used in suspend/resume path to resume cpuidle */
+void cpuidle_resume(void)
+{
+ mutex_lock(&cpuidle_lock);
+ cpuidle_install_idle_handler();
+ mutex_unlock(&cpuidle_lock);
+}
+
+/**
+ * cpuidle_enable_device - enables idle PM for a CPU
+ * @dev: the CPU
+ *
+ * This function must be called between cpuidle_pause_and_lock and
+ * cpuidle_resume_and_unlock when used externally.
+ */
+int cpuidle_enable_device(struct cpuidle_device *dev)
+{
+ int ret;
+ struct cpuidle_driver *drv;
+
+ if (!dev)
+ return -EINVAL;
+
+ if (dev->enabled)
+ return 0;
+
+ drv = cpuidle_get_cpu_driver(dev);
+
+ if (!drv || !cpuidle_curr_governor)
+ return -EIO;
+
+ if (!dev->registered)
+ return -EINVAL;
+
+ ret = cpuidle_add_device_sysfs(dev);
+ if (ret)
+ return ret;
+
+ if (cpuidle_curr_governor->enable &&
+ (ret = cpuidle_curr_governor->enable(drv, dev)))
+ goto fail_sysfs;
+
+ smp_wmb();
+
+ dev->enabled = 1;
+
+ enabled_devices++;
+ return 0;
+
+fail_sysfs:
+ cpuidle_remove_device_sysfs(dev);
+
+ return ret;
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_enable_device);
+
+/**
+ * cpuidle_disable_device - disables idle PM for a CPU
+ * @dev: the CPU
+ *
+ * This function must be called between cpuidle_pause_and_lock and
+ * cpuidle_resume_and_unlock when used externally.
+ */
+void cpuidle_disable_device(struct cpuidle_device *dev)
+{
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
+ if (!dev || !dev->enabled)
+ return;
+
+ if (!drv || !cpuidle_curr_governor)
+ return;
+
+ dev->enabled = 0;
+
+ if (cpuidle_curr_governor->disable)
+ cpuidle_curr_governor->disable(drv, dev);
+
+ cpuidle_remove_device_sysfs(dev);
+ enabled_devices--;
+}
+
+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);
+}
+
+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
+ * @dev: the cpu
+ *
+ * cpuidle_lock mutex must be held before this is called
+ */
+static int __cpuidle_register_device(struct cpuidle_device *dev)
+{
+ int ret;
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
+ if (!try_module_get(drv->owner))
+ return -EINVAL;
+
+ per_cpu(cpuidle_devices, dev->cpu) = dev;
+ list_add(&dev->device_list, &cpuidle_detected_devices);
+
+ ret = cpuidle_coupled_register_device(dev);
+ if (ret)
+ __cpuidle_unregister_device(dev);
+ else
+ dev->registered = 1;
+
+ return ret;
+}
+
+/**
+ * cpuidle_register_device - registers a CPU's idle PM feature
+ * @dev: the cpu
+ */
+int cpuidle_register_device(struct cpuidle_device *dev)
+{
+ int ret = -EBUSY;
+
+ if (!dev)
+ return -EINVAL;
+
+ mutex_lock(&cpuidle_lock);
+
+ 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_install_idle_handler();
+
+out_unlock:
+ mutex_unlock(&cpuidle_lock);
+
+ return ret;
+
+out_sysfs:
+ cpuidle_remove_sysfs(dev);
+out_unregister:
+ __cpuidle_unregister_device(dev);
+ goto out_unlock;
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_register_device);
+
+/**
+ * cpuidle_unregister_device - unregisters a CPU's idle PM feature
+ * @dev: the cpu
+ */
+void cpuidle_unregister_device(struct cpuidle_device *dev)
+{
+ if (!dev || dev->registered == 0)
+ return;
+
+ cpuidle_pause_and_lock();
+
+ cpuidle_disable_device(dev);
+
+ cpuidle_remove_sysfs(dev);
+
+ __cpuidle_unregister_device(dev);
+
+ cpuidle_coupled_unregister_device(dev);
+
+ cpuidle_resume_and_unlock();
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
+
+/**
+ * cpuidle_unregister: unregister a driver and the devices. This function
+ * can be used only if the driver has been previously registered through
+ * the cpuidle_register function.
+ *
+ * @drv: a valid pointer to a struct cpuidle_driver
+ */
+void cpuidle_unregister(struct cpuidle_driver *drv)
+{
+ int cpu;
+ struct cpuidle_device *device;
+
+ for_each_cpu(cpu, drv->cpumask) {
+ device = &per_cpu(cpuidle_dev, cpu);
+ cpuidle_unregister_device(device);
+ }
+
+ cpuidle_unregister_driver(drv);
+}
+EXPORT_SYMBOL_GPL(cpuidle_unregister);
+
+/**
+ * cpuidle_register: registers the driver and the cpu devices with the
+ * coupled_cpus passed as parameter. This function is used for all common
+ * initialization pattern there are in the arch specific drivers. The
+ * devices is globally defined in this file.
+ *
+ * @drv : a valid pointer to a struct cpuidle_driver
+ * @coupled_cpus: a cpumask for the coupled states
+ *
+ * Returns 0 on success, < 0 otherwise
+ */
+int cpuidle_register(struct cpuidle_driver *drv,
+ const struct cpumask *const coupled_cpus)
+{
+ int ret, cpu;
+ struct cpuidle_device *device;
+
+ ret = cpuidle_register_driver(drv);
+ if (ret) {
+ pr_err("failed to register cpuidle driver\n");
+ return ret;
+ }
+
+ 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 be
+ * enabled in the kernel even if the cpuidle driver does not
+ * use it. Note, coupled_cpus is a struct copy.
+ */
+ if (coupled_cpus)
+ device->coupled_cpus = *coupled_cpus;
+#endif
+ ret = cpuidle_register_device(device);
+ if (!ret)
+ continue;
+
+ pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
+
+ cpuidle_unregister(drv);
+ break;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpuidle_register);
+
+#ifdef CONFIG_SMP
+
+/*
+ * 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,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int cpuidle_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ wake_up_all_idle_cpus();
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpuidle_latency_notifier = {
+ .notifier_call = cpuidle_latency_notify,
+};
+
+static inline void latency_notifier_init(struct notifier_block *n)
+{
+ pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
+}
+
+#else /* CONFIG_SMP */
+
+#define latency_notifier_init(x) do { } while (0)
+
+#endif /* CONFIG_SMP */
+
+/**
+ * cpuidle_init - core initializer
+ */
+static int __init cpuidle_init(void)
+{
+ int ret;
+
+ if (cpuidle_disabled())
+ return -ENODEV;
+
+ ret = cpuidle_add_interface(cpu_subsys.dev_root);
+ if (ret)
+ return ret;
+
+ latency_notifier_init(&cpuidle_latency_notifier);
+
+ return 0;
+}
+
+module_param(off, int, 0444);
+core_initcall(cpuidle_init);
Code Review / kvmfornfv.git / blobdiff