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-rw-r--r--drivers/cpuidle/driver.c387
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);
+}