/**
* cpuidle_register_device - registers a CPU's idle PM feature
* @dev: the cpu
*/
int cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
if (!sys_dev)
return -EINVAL;
if (!try_module_get(cpuidle_curr_driver->owner))
return -EINVAL;
init_completion(&dev->kobj_unregister);
mutex_lock(&cpuidle_lock);
poll_idle_init(dev);
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
if ((ret = cpuidle_add_sysfs(sys_dev))) {
mutex_unlock(&cpuidle_lock);
module_put(cpuidle_curr_driver->owner);
return ret;
}
cpuidle_enable_device(dev);
cpuidle_install_idle_handler();
mutex_unlock(&cpuidle_lock);
return 0;
}
/**
* __cpuidle_register_device - internal register function called before register
* and enable routines
* @dev: the cpu
*
* cpuidle_lock mutex must be held before this is called
*/
static int __cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
if (!sys_dev)
return -EINVAL;
if (!try_module_get(cpuidle_driver->owner))
return -EINVAL;
init_completion(&dev->kobj_unregister);
poll_idle_init(dev);
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
if ((ret = cpuidle_add_sysfs(sys_dev))) {
module_put(cpuidle_driver->owner);
return ret;
}
dev->registered = 1;
return 0;
}
/**
* cpuidle_enable_device - enables idle PM for a CPU
* @dev: the CPU
*
* This function must be called between cpuidle_pause_and_lock and
* cpuidle_resume_and_unlock when used externally.
*/
int cpuidle_enable_device(struct cpuidle_device *dev)
{
int ret, i;
struct cpuidle_driver *drv;
if (!dev)
return -EINVAL;
if (dev->enabled)
return 0;
drv = cpuidle_get_cpu_driver(dev);
if (!drv || !cpuidle_curr_governor)
return -EIO;
if (!dev->state_count)
dev->state_count = drv->state_count;
if (dev->registered == 0) {
ret = __cpuidle_register_device(dev);
if (ret)
return ret;
}
cpuidle_enter_ops = drv->en_core_tk_irqen ?
cpuidle_enter_tk : cpuidle_enter;
poll_idle_init(drv);
ret = cpuidle_add_device_sysfs(dev);
if (ret)
return ret;
if (cpuidle_curr_governor->enable &&
(ret = cpuidle_curr_governor->enable(drv, dev)))
goto fail_sysfs;
for (i = 0; i < dev->state_count; i++) {
dev->states_usage[i].usage = 0;
dev->states_usage[i].time = 0;
}
dev->last_residency = 0;
smp_wmb();
dev->enabled = 1;
enabled_devices++;
return 0;
fail_sysfs:
cpuidle_remove_device_sysfs(dev);
return ret;
}
/**
* __cpuidle_register_device - internal register function called before register
* and enable routines
* @dev: the cpu
*
* cpuidle_lock mutex must be held before this is called
*/
static int __cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
if (!sys_dev)
return -EINVAL;
if (!try_module_get(cpuidle_driver->owner))
return -EINVAL;
init_completion(&dev->kobj_unregister);
poll_idle_init(dev);
/*
* cpuidle driver should set the dev->power_specified bit
* before registering the device if the driver provides
* power_usage numbers.
*
* For those devices whose ->power_specified is not set,
* we fill in power_usage with decreasing values as the
* cpuidle code has an implicit assumption that state Cn
* uses less power than C(n-1).
*
* With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned
* an power value of -1. So we use -2, -3, etc, for other
* c-states.
*/
if (!dev->power_specified)
{
int i;
for (i = CPUIDLE_DRIVER_STATE_START; i < dev->state_count; i++)
dev->states[i].power_usage = -1 - i;
}
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
if ((ret = cpuidle_add_sysfs(sys_dev))) {
module_put(cpuidle_driver->owner);
return ret;
}
dev->registered = 1;
return 0;
}
/**
* cpuidle_enable_device - enables idle PM for a CPU
* @dev: the CPU
*
* This function must be called between cpuidle_pause_and_lock and
* cpuidle_resume_and_unlock when used externally.
*/
int cpuidle_enable_device(struct cpuidle_device *dev)
{
int ret, i;
if (dev->enabled)
return 0;
if (!cpuidle_get_driver() || !cpuidle_curr_governor)
return -EIO;
if (!dev->state_count)
return -EINVAL;
if (dev->registered == 0) {
ret = __cpuidle_register_device(dev);
if (ret)
return ret;
}
poll_idle_init(dev);
if ((ret = cpuidle_add_state_sysfs(dev)))
return ret;
if (cpuidle_curr_governor->enable &&
(ret = cpuidle_curr_governor->enable(dev)))
goto fail_sysfs;
for (i = 0; i < dev->state_count; i++) {
dev->states[i].usage = 0;
dev->states[i].time = 0;
}
dev->last_residency = 0;
dev->last_state = NULL;
smp_wmb();
dev->enabled = 1;
enabled_devices++;
return 0;
fail_sysfs:
cpuidle_remove_state_sysfs(dev);
return ret;
}
