1 files changed, 387 insertions, 0 deletions
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
new file mode 100644
index 000000000..f70aa17e2
--- /dev/null
+++ b/drivers/cpuidle/driver.c
@@ -0,0 +1,387 @@
+/*
+ * driver.c - driver support
+ *
+ * (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/mutex.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/idle.h>
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/tick.h>
+#include <linux/cpu.h>
+
+#include "cpuidle.h"
+
+DEFINE_SPINLOCK(cpuidle_driver_lock);
+
+#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
+
+static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);
+
+/**
+ * __cpuidle_get_cpu_driver - return the cpuidle driver tied to a CPU.
+ * @cpu: the CPU handled by the driver
+ *
+ * Returns a pointer to struct cpuidle_driver or NULL if no driver has been
+ * registered for @cpu.
+ */
+static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
+{
+	return per_cpu(cpuidle_drivers, cpu);
+}
+
+/**
+ * __cpuidle_unset_driver - unset per CPU driver variables.
+ * @drv: a valid pointer to a struct cpuidle_driver
+ *
+ * For each CPU in the driver's CPU mask, unset the registered driver per CPU
+ * variable. If @drv is different from the registered driver, the corresponding
+ * variable is not cleared.
+ */
+static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
+{
+	int cpu;
+
+	for_each_cpu(cpu, drv->cpumask) {
+
+		if (drv != __cpuidle_get_cpu_driver(cpu))
+			continue;
+
+		per_cpu(cpuidle_drivers, cpu) = NULL;
+	}
+}
+
+/**
+ * __cpuidle_set_driver - set per CPU driver variables for the given driver.
+ * @drv: a valid pointer to a struct cpuidle_driver
+ *
+ * Returns 0 on success, -EBUSY if any CPU in the cpumask have a driver
+ * different from drv already.
+ */
+static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
+{
+	int cpu;
+
+	for_each_cpu(cpu, drv->cpumask) {
+		struct cpuidle_driver *old_drv;
+
+		old_drv = __cpuidle_get_cpu_driver(cpu);
+		if (old_drv && old_drv != drv)
+			return -EBUSY;
+	}
+
+	for_each_cpu(cpu, drv->cpumask)
+		per_cpu(cpuidle_drivers, cpu) = drv;
+
+	return 0;
+}
+
+#else
+
+static struct cpuidle_driver *cpuidle_curr_driver;
+
+/**
+ * __cpuidle_get_cpu_driver - return the global cpuidle driver pointer.
+ * @cpu: ignored without the multiple driver support
+ *
+ * Return a pointer to a struct cpuidle_driver object or NULL if no driver was
+ * previously registered.
+ */
+static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
+{
+	return cpuidle_curr_driver;
+}
+
+/**
+ * __cpuidle_set_driver - assign the global cpuidle driver variable.
+ * @drv: pointer to a struct cpuidle_driver object
+ *
+ * Returns 0 on success, -EBUSY if the driver is already registered.
+ */
+static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
+{
+	if (cpuidle_curr_driver)
+		return -EBUSY;
+
+	cpuidle_curr_driver = drv;
+
+	return 0;
+}
+
+/**
+ * __cpuidle_unset_driver - unset the global cpuidle driver variable.
+ * @drv: a pointer to a struct cpuidle_driver
+ *
+ * Reset the global cpuidle variable to NULL.  If @drv does not match the
+ * registered driver, do nothing.
+ */
+static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
+{
+	if (drv == cpuidle_curr_driver)
+		cpuidle_curr_driver = NULL;
+}
+
+#endif
+
+/**
+ * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer on a cpu
+ * @arg: a void pointer used to match the SMP cross call API
+ *
+ * If @arg is NULL broadcast is disabled otherwise enabled
+ *
+ * This function is executed per CPU by an SMP cross call.  It's not
+ * supposed to be called directly.
+ */
+static void cpuidle_setup_broadcast_timer(void *arg)
+{
+	if (arg)
+		tick_broadcast_enable();
+	else
+		tick_broadcast_disable();
+}
+
+/**
+ * __cpuidle_driver_init - initialize the driver's internal data
+ * @drv: a valid pointer to a struct cpuidle_driver
+ */
+static void __cpuidle_driver_init(struct cpuidle_driver *drv)
+{
+	int i;
+
+	/*
+	 * Use all possible CPUs as the default, because if the kernel boots
+	 * with some CPUs offline and then we online one of them, the CPU
+	 * notifier has to know which driver to assign.
+	 */
+	if (!drv->cpumask)
+		drv->cpumask = (struct cpumask *)cpu_possible_mask;
+
+	for (i = 0; i < drv->state_count; i++) {
+		struct cpuidle_state *s = &drv->states[i];
+
+		/*
+		 * Look for the timer stop flag in the different states and if
+		 * it is found, indicate that the broadcast timer has to be set
+		 * up.
+		 */
+		if (s->flags & CPUIDLE_FLAG_TIMER_STOP)
+			drv->bctimer = 1;
+
+		/*
+		 * The core will use the target residency and exit latency
+		 * values in nanoseconds, but allow drivers to provide them in
+		 * microseconds too.
+		 */
+		if (s->target_residency > 0)
+			s->target_residency_ns = s->target_residency * NSEC_PER_USEC;
+		else if (s->target_residency_ns < 0)
+			s->target_residency_ns = 0;
+
+		if (s->exit_latency > 0)
+			s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC;
+		else if (s->exit_latency_ns < 0)
+			s->exit_latency_ns =  0;
+	}
+}
+
+/**
+ * __cpuidle_register_driver: register the driver
+ * @drv: a valid pointer to a struct cpuidle_driver
+ *
+ * Do some sanity checks, initialize the driver, assign the driver to the
+ * global cpuidle driver variable(s) and set up the broadcast timer if the
+ * cpuidle driver has some states that shut down the local timer.
+ *
+ * Returns 0 on success, a negative error code otherwise:
+ *  * -EINVAL if the driver pointer is NULL or no idle states are available
+ *  * -ENODEV if the cpuidle framework is disabled
+ *  * -EBUSY if the driver is already assigned to the global variable(s)
+ */
+static int __cpuidle_register_driver(struct cpuidle_driver *drv)
+{
+	int ret;
+
+	if (!drv || !drv->state_count)
+		return -EINVAL;
+
+	ret = cpuidle_coupled_state_verify(drv);
+	if (ret)
+		return ret;
+
+	if (cpuidle_disabled())
+		return -ENODEV;
+
+	__cpuidle_driver_init(drv);
+
+	ret = __cpuidle_set_driver(drv);
+	if (ret)
+		return ret;
+
+	if (drv->bctimer)
+		on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
+				 (void *)1, 1);
+
+	return 0;
+}
+
+/**
+ * __cpuidle_unregister_driver - unregister the driver
+ * @drv: a valid pointer to a struct cpuidle_driver
+ *
+ * Check if the driver is no longer in use, reset the global cpuidle driver
+ * variable(s) and disable the timer broadcast notification mechanism if it was
+ * in use.
+ *
+ */
+static void __cpuidle_unregister_driver(struct cpuidle_driver *drv)
+{
+	if (drv->bctimer) {
+		drv->bctimer = 0;
+		on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
+				 NULL, 1);
+	}
+
+	__cpuidle_unset_driver(drv);
+}
+
+/**
+ * cpuidle_register_driver - registers a driver
+ * @drv: a pointer to a valid struct cpuidle_driver
+ *
+ * Register the driver under a lock to prevent concurrent attempts to
+ * [un]register the driver from occuring at the same time.
+ *
+ * Returns 0 on success, a negative error code (returned by
+ * __cpuidle_register_driver()) otherwise.
+ */
+int cpuidle_register_driver(struct cpuidle_driver *drv)
+{
+	struct cpuidle_governor *gov;
+	int ret;
+
+	spin_lock(&cpuidle_driver_lock);
+	ret = __cpuidle_register_driver(drv);
+	spin_unlock(&cpuidle_driver_lock);
+
+	if (!ret && !strlen(param_governor) && drv->governor &&
+	    (cpuidle_get_driver() == drv)) {
+		mutex_lock(&cpuidle_lock);
+		gov = cpuidle_find_governor(drv->governor);
+		if (gov) {
+			cpuidle_prev_governor = cpuidle_curr_governor;
+			if (cpuidle_switch_governor(gov) < 0)
+				cpuidle_prev_governor = NULL;
+		}
+		mutex_unlock(&cpuidle_lock);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cpuidle_register_driver);
+
+/**
+ * cpuidle_unregister_driver - unregisters a driver
+ * @drv: a pointer to a valid struct cpuidle_driver
+ *
+ * Unregisters the cpuidle driver under a lock to prevent concurrent attempts
+ * to [un]register the driver from occuring at the same time.  @drv has to
+ * match the currently registered driver.
+ */
+void cpuidle_unregister_driver(struct cpuidle_driver *drv)
+{
+	bool enabled = (cpuidle_get_driver() == drv);
+
+	spin_lock(&cpuidle_driver_lock);
+	__cpuidle_unregister_driver(drv);
+	spin_unlock(&cpuidle_driver_lock);
+
+	if (!enabled)
+		return;
+
+	mutex_lock(&cpuidle_lock);
+	if (cpuidle_prev_governor) {
+		if (!cpuidle_switch_governor(cpuidle_prev_governor))
+			cpuidle_prev_governor = NULL;
+	}
+	mutex_unlock(&cpuidle_lock);
+}
+EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
+
+/**
+ * cpuidle_get_driver - return the driver tied to the current CPU.
+ *
+ * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered.
+ */
+struct cpuidle_driver *cpuidle_get_driver(void)
+{
+	struct cpuidle_driver *drv;
+	int cpu;
+
+	cpu = get_cpu();
+	drv = __cpuidle_get_cpu_driver(cpu);
+	put_cpu();
+
+	return drv;
+}
+EXPORT_SYMBOL_GPL(cpuidle_get_driver);
+
+/**
+ * cpuidle_get_cpu_driver - return the driver registered for a CPU.
+ * @dev: a valid pointer to a struct cpuidle_device
+ *
+ * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered
+ * for the CPU associated with @dev.
+ */
+struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
+{
+	if (!dev)
+		return NULL;
+
+	return __cpuidle_get_cpu_driver(dev->cpu);
+}
+EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver);
+
+/**
+ * cpuidle_driver_state_disabled - Disable or enable an idle state
+ * @drv: cpuidle driver owning the state
+ * @idx: State index
+ * @disable: Whether or not to disable the state
+ */
+void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
+				 bool disable)
+{
+	unsigned int cpu;
+
+	mutex_lock(&cpuidle_lock);
+
+	spin_lock(&cpuidle_driver_lock);
+
+	if (!drv->cpumask) {
+		drv->states[idx].flags |= CPUIDLE_FLAG_UNUSABLE;
+		goto unlock;
+	}
+
+	for_each_cpu(cpu, drv->cpumask) {
+		struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+
+		if (!dev)
+			continue;
+
+		if (disable)
+			dev->states_usage[idx].disable |= CPUIDLE_STATE_DISABLED_BY_DRIVER;
+		else
+			dev->states_usage[idx].disable &= ~CPUIDLE_STATE_DISABLED_BY_DRIVER;
+	}
+
+unlock:
+	spin_unlock(&cpuidle_driver_lock);
+
+	mutex_unlock(&cpuidle_lock);
+}