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-rw-r--r--drivers/cpuidle/cpuidle.c295
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
new file mode 100644
index 0000000..fdf4106
--- /dev/null
+++ b/drivers/cpuidle/cpuidle.c
@@ -0,0 +1,295 @@
+/*
+ * 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/kernel.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/notifier.h>
+#include <linux/latency.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+
+#include "cpuidle.h"
+
+DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+EXPORT_PER_CPU_SYMBOL_GPL(cpuidle_devices);
+
+DEFINE_MUTEX(cpuidle_lock);
+LIST_HEAD(cpuidle_detected_devices);
+static void (*pm_idle_old)(void);
+
+static int enabled_devices;
+
+/**
+ * cpuidle_idle_call - the main idle loop
+ *
+ * NOTE: no locks or semaphores should be used here
+ */
+static void cpuidle_idle_call(void)
+{
+ struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices);
+ struct cpuidle_state *target_state;
+ int next_state;
+
+ /* check if the device is ready */
+ if (!dev || !dev->enabled) {
+ if (pm_idle_old)
+ pm_idle_old();
+ else
+ local_irq_enable();
+ return;
+ }
+
+ /* ask the governor for the next state */
+ next_state = cpuidle_curr_governor->select(dev);
+ if (need_resched())
+ return;
+ target_state = &dev->states[next_state];
+
+ /* enter the state and update stats */
+ dev->last_residency = target_state->enter(dev, target_state);
+ dev->last_state = target_state;
+ target_state->time += dev->last_residency;
+ target_state->usage++;
+
+ /* give the governor an opportunity to reflect on the outcome */
+ if (cpuidle_curr_governor->reflect)
+ cpuidle_curr_governor->reflect(dev);
+}
+
+/**
+ * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
+ */
+void cpuidle_install_idle_handler(void)
+{
+ if (enabled_devices && (pm_idle != cpuidle_idle_call)) {
+ /* Make sure all changes finished before we switch to new idle */
+ smp_wmb();
+ pm_idle = cpuidle_idle_call;
+ }
+}
+
+/**
+ * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
+ */
+void cpuidle_uninstall_idle_handler(void)
+{
+ if (enabled_devices && (pm_idle != pm_idle_old)) {
+ pm_idle = pm_idle_old;
+ cpu_idle_wait();
+ }
+}
+
+/**
+ * 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);
+
+/**
+ * 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, i;
+
+ if (dev->enabled)
+ return 0;
+ if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+ return -EIO;
+ if (!dev->state_count)
+ return -EINVAL;
+
+ if ((ret = cpuidle_add_state_sysfs(dev)))
+ return ret;
+
+ if (cpuidle_curr_governor->enable &&
+ (ret = cpuidle_curr_governor->enable(dev)))
+ goto fail_sysfs;
+
+ for (i = 0; i < dev->state_count; i++) {
+ dev->states[i].usage = 0;
+ dev->states[i].time = 0;
+ }
+ dev->last_residency = 0;
+ dev->last_state = NULL;
+
+ smp_wmb();
+
+ dev->enabled = 1;
+
+ enabled_devices++;
+ return 0;
+
+fail_sysfs:
+ cpuidle_remove_state_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)
+{
+ if (!dev->enabled)
+ return;
+ if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+ return;
+
+ dev->enabled = 0;
+
+ if (cpuidle_curr_governor->disable)
+ cpuidle_curr_governor->disable(dev);
+
+ cpuidle_remove_state_sysfs(dev);
+ enabled_devices--;
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_disable_device);
+
+/**
+ * cpuidle_register_device - registers a CPU's idle PM feature
+ * @dev: the cpu
+ */
+int cpuidle_register_device(struct cpuidle_device *dev)
+{
+ int ret;
+ struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+
+ if (!sys_dev)
+ return -EINVAL;
+ if (!try_module_get(cpuidle_curr_driver->owner))
+ return -EINVAL;
+
+ init_completion(&dev->kobj_unregister);
+
+ mutex_lock(&cpuidle_lock);
+
+ per_cpu(cpuidle_devices, dev->cpu) = dev;
+ list_add(&dev->device_list, &cpuidle_detected_devices);
+ if ((ret = cpuidle_add_sysfs(sys_dev))) {
+ mutex_unlock(&cpuidle_lock);
+ module_put(cpuidle_curr_driver->owner);
+ return ret;
+ }
+
+ cpuidle_enable_device(dev);
+ cpuidle_install_idle_handler();
+
+ mutex_unlock(&cpuidle_lock);
+
+ return 0;
+
+}
+
+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)
+{
+ struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+
+ cpuidle_pause_and_lock();
+
+ cpuidle_disable_device(dev);
+
+ cpuidle_remove_sysfs(sys_dev);
+ list_del(&dev->device_list);
+ wait_for_completion(&dev->kobj_unregister);
+ per_cpu(cpuidle_devices, dev->cpu) = NULL;
+
+ cpuidle_resume_and_unlock();
+
+ module_put(cpuidle_curr_driver->owner);
+}
+
+EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
+
+#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,
+ * 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)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpuidle_latency_notifier = {
+ .notifier_call = cpuidle_latency_notify,
+};
+
+#define latency_notifier_init(x) do { register_latency_notifier(x); } while (0)
+
+#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;
+
+ pm_idle_old = pm_idle;
+
+ ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
+ if (ret)
+ return ret;
+
+ latency_notifier_init(&cpuidle_latency_notifier);
+
+ return 0;
+}
+
+core_initcall(cpuidle_init);
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