/* * driver.c - driver support * * (C) 2006-2007 Venkatesh Pallipadi <[email protected]> * Shaohua Li <[email protected]> * Adam Belay <[email protected]> * * 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 <linux/math64.h> #include "cpuidle.h" DEFINE_SPINLOCK(…); #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) { … } /** * __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) { … } /** * __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) { … } #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) { … } /** * __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) { … } /** * __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) { … } /** * __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) { … } /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … }
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