Initial import

1 files changed, 633 insertions, 0 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
new file mode 100644
index 000000000..61c417b9e
--- /dev/null
+++ b/drivers/cpuidle/cpuidle.c
@@ -0,0 +1,633 @@
+/*
+ * 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);