72 lines
1.4 KiB
C
72 lines
1.4 KiB
C
/*
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* driver.c - driver support
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*
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* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
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* Shaohua Li <shaohua.li@intel.com>
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* Adam Belay <abelay@novell.com>
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*
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* This code is licenced under the GPL.
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*/
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#include <linux/mutex.h>
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#include <linux/module.h>
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#include <linux/cpuidle.h>
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#include "cpuidle.h"
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static struct cpuidle_driver *cpuidle_curr_driver;
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DEFINE_SPINLOCK(cpuidle_driver_lock);
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/**
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* cpuidle_register_driver - registers a driver
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* @drv: the driver
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*/
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int cpuidle_register_driver(struct cpuidle_driver *drv)
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{
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if (!drv)
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return -EINVAL;
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if (cpuidle_disabled())
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return -ENODEV;
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spin_lock(&cpuidle_driver_lock);
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if (cpuidle_curr_driver) {
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spin_unlock(&cpuidle_driver_lock);
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return -EBUSY;
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}
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cpuidle_curr_driver = drv;
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spin_unlock(&cpuidle_driver_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(cpuidle_register_driver);
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/**
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* cpuidle_get_driver - return the current driver
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*/
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struct cpuidle_driver *cpuidle_get_driver(void)
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{
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return cpuidle_curr_driver;
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}
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EXPORT_SYMBOL_GPL(cpuidle_get_driver);
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/**
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* cpuidle_unregister_driver - unregisters a driver
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* @drv: the driver
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*/
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void cpuidle_unregister_driver(struct cpuidle_driver *drv)
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{
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if (drv != cpuidle_curr_driver) {
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WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
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drv->name);
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return;
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}
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spin_lock(&cpuidle_driver_lock);
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cpuidle_curr_driver = NULL;
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spin_unlock(&cpuidle_driver_lock);
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}
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EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
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