mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Rafael J. Wysocki](/assets/img/avatar_default.png)
The cpuidle_driver_ref() and cpuidle_driver_unref() functions are not used and the refcnt field in struct cpuidle_driver operated by them is not updated anywhere else (so it is permanently equal to 0), so drop both of them along with refcnt. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
383 lines
9.5 KiB
C
383 lines
9.5 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/sched.h>
|
|
#include <linux/sched/idle.h>
|
|
#include <linux/cpuidle.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/tick.h>
|
|
#include <linux/cpu.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;
|
|
|
|
if (s->exit_latency > 0)
|
|
s->exit_latency_ns = s->exit_latency * 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 occuring 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 occuring 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);
|
|
}
|