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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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(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; else s->target_residency = div_u64(s->target_residency_ns, NSEC_PER_USEC);
if (s->exit_latency > 0) s->exit_latency_ns = mul_u32_u32(s->exit_latency, NSEC_PER_USEC); else if (s->exit_latency_ns < 0) s->exit_latency_ns = 0; else s->exit_latency = div_u64(s->exit_latency_ns, NSEC_PER_USEC); }}
/** * __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 occurring 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 occurring 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);}