/* * 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/cpuidle.h> #include "cpuidle.h" DEFINE_SPINLOCK(cpuidle_driver_lock); static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu); static struct cpuidle_driver * __cpuidle_get_cpu_driver(int cpu); static void __cpuidle_driver_init(struct cpuidle_driver *drv) { drv->refcnt = 0; } static int __cpuidle_register_driver(struct cpuidle_driver *drv, int cpu) { if (!drv || !drv->state_count) return -EINVAL; if (cpuidle_disabled()) return -ENODEV; if (__cpuidle_get_cpu_driver(cpu)) return -EBUSY; __cpuidle_driver_init(drv); __cpuidle_set_cpu_driver(drv, cpu); return 0; } static void __cpuidle_unregister_driver(struct cpuidle_driver *drv, int cpu) { if (drv != __cpuidle_get_cpu_driver(cpu)) return; if (!WARN_ON(drv->refcnt > 0)) __cpuidle_set_cpu_driver(NULL, cpu); } #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu) { per_cpu(cpuidle_drivers, cpu) = drv; } static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return per_cpu(cpuidle_drivers, cpu); } static void __cpuidle_unregister_all_cpu_driver(struct cpuidle_driver *drv) { int cpu; for_each_present_cpu(cpu) __cpuidle_unregister_driver(drv, cpu); } static int __cpuidle_register_all_cpu_driver(struct cpuidle_driver *drv) { int ret = 0; int i, cpu; for_each_present_cpu(cpu) { ret = __cpuidle_register_driver(drv, cpu); if (ret) break; } if (ret) for_each_present_cpu(i) { if (i == cpu) break; __cpuidle_unregister_driver(drv, i); } return ret; } int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu) { int ret; spin_lock(&cpuidle_driver_lock); ret = __cpuidle_register_driver(drv, cpu); spin_unlock(&cpuidle_driver_lock); return ret; } void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu) { spin_lock(&cpuidle_driver_lock); __cpuidle_unregister_driver(drv, cpu); spin_unlock(&cpuidle_driver_lock); } /** * cpuidle_register_driver - registers a driver * @drv: the driver */ int cpuidle_register_driver(struct cpuidle_driver *drv) { int ret; spin_lock(&cpuidle_driver_lock); ret = __cpuidle_register_all_cpu_driver(drv); spin_unlock(&cpuidle_driver_lock); return ret; } EXPORT_SYMBOL_GPL(cpuidle_register_driver); /** * cpuidle_unregister_driver - unregisters a driver * @drv: the driver */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { spin_lock(&cpuidle_driver_lock); __cpuidle_unregister_all_cpu_driver(drv); spin_unlock(&cpuidle_driver_lock); } EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); #else static struct cpuidle_driver *cpuidle_curr_driver; static inline void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu) { cpuidle_curr_driver = drv; } static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return cpuidle_curr_driver; } /** * cpuidle_register_driver - registers a driver * @drv: the driver */ int cpuidle_register_driver(struct cpuidle_driver *drv) { int ret, cpu; cpu = get_cpu(); spin_lock(&cpuidle_driver_lock); ret = __cpuidle_register_driver(drv, cpu); spin_unlock(&cpuidle_driver_lock); put_cpu(); return ret; } EXPORT_SYMBOL_GPL(cpuidle_register_driver); /** * cpuidle_unregister_driver - unregisters a driver * @drv: the driver */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { int cpu; cpu = get_cpu(); spin_lock(&cpuidle_driver_lock); __cpuidle_unregister_driver(drv, cpu); spin_unlock(&cpuidle_driver_lock); put_cpu(); } EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); #endif /** * cpuidle_get_driver - return the current driver */ 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 tied with a cpu */ 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); struct cpuidle_driver *cpuidle_driver_ref(void) { struct cpuidle_driver *drv; spin_lock(&cpuidle_driver_lock); drv = cpuidle_get_driver(); drv->refcnt++; spin_unlock(&cpuidle_driver_lock); return drv; } void cpuidle_driver_unref(void) { struct cpuidle_driver *drv = cpuidle_get_driver(); spin_lock(&cpuidle_driver_lock); if (drv && !WARN_ON(drv->refcnt <= 0)) drv->refcnt--; spin_unlock(&cpuidle_driver_lock); }