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/*
* 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 <linux/cpumask.h>
#include <linux/clockchips.h>
#include "cpuidle.h"
DEFINE_SPINLOCK(cpuidle_driver_lock);
#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);
static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
return per_cpu(cpuidle_drivers, cpu);
}
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;
}
}
static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
{
int cpu;
for_each_cpu(cpu, drv->cpumask) {
if (__cpuidle_get_cpu_driver(cpu)) {
__cpuidle_unset_driver(drv);
return -EBUSY;
}
per_cpu(cpuidle_drivers, cpu) = drv;
}
return 0;
}
#else
static struct cpuidle_driver *cpuidle_curr_driver;
static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
return cpuidle_curr_driver;
}
static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
{
if (cpuidle_curr_driver)
return -EBUSY;
cpuidle_curr_driver = drv;
return 0;
}
static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
{
if (drv == cpuidle_curr_driver)
cpuidle_curr_driver = NULL;
}
#endif
static void cpuidle_setup_broadcast_timer(void *arg)
{
int cpu = smp_processor_id();
clockevents_notify((long)(arg), &cpu);
}
static int __cpuidle_driver_init(struct cpuidle_driver *drv)
{
int i;
drv->refcnt = 0;
if (!drv->cpumask)
drv->cpumask = (struct cpumask *)cpu_possible_mask;
for (i = drv->state_count - 1; i >= 0 ; i--) {
if (!(drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP))
continue;
drv->bctimer = 1;
break;
}
return 0;
}
static int __cpuidle_register_driver(struct cpuidle_driver *drv)
{
int ret;
if (!drv || !drv->state_count)
return -EINVAL;
if (cpuidle_disabled())
return -ENODEV;
ret = __cpuidle_driver_init(drv);
if (ret)
return ret;
ret = __cpuidle_set_driver(drv);
if (ret)
return ret;
if (drv->bctimer)
on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
(void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1);
return 0;
}
/**
* cpuidle_unregister_driver - unregisters a driver
* @drv: the driver
*/
static void __cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
if (WARN_ON(drv->refcnt > 0))
return;
if (drv->bctimer) {
drv->bctimer = 0;
on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
(void *)CLOCK_EVT_NOTIFY_BROADCAST_OFF, 1);
}
__cpuidle_unset_driver(drv);
}
/**
* 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_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_driver(drv);
spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
/**
* 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);
}
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