1 files changed, 295 insertions, 0 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
new file mode 100644
index 000000000000..fdf4106b817b
--- /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);