linux/drivers/cpuidle/driver.c
Daniel Lezcano 8aef33a7cf cpuidle: remove the power_specified field in the driver
We realized that the power usage field is never filled and when it
is filled for tegra, the power_specified flag is not set causing all
of these values to be reset when the driver is initialized with
set_power_state().

However, the power_specified flag can be simply removed under the
assumption that the states are always backward sorted, which is the
case with the current code.

This change allows the menu governor select function and the
cpuidle_play_dead() to be simplified.  Moreover, the
set_power_states() function can removed as it does not make sense
any more.

Drop the power_specified flag from struct cpuidle_driver and make
the related changes as described above.

As a consequence, this also fixes the bug where on the dynamic
C-states system, the power fields are not initialized.

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=42870
References: https://bugzilla.kernel.org/show_bug.cgi?id=43349
References: https://lkml.org/lkml/2012/10/16/518
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-15 14:18:04 +01:00

244 lines
4.8 KiB
C

/*
* 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);
}