zephyr/include/power.h

126 lines
4.3 KiB
C

/*
* Copyright (c) 2012-2014 Wind River Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __INCpower
#define __INCpower
#ifdef __cplusplus
extern "C" {
#endif
#ifdef CONFIG_SYS_POWER_MANAGEMENT
/* Constants identifying power state categories */
#define SYS_PM_ACTIVE_STATE 0 /* SOC and CPU are in active state */
#define SYS_PM_LOW_POWER_STATE 1 /* CPU low power state */
#define SYS_PM_DEEP_SLEEP 2 /* SOC low power state */
#define SYS_PM_NOT_HANDLED SYS_PM_ACTIVE_STATE
extern unsigned char _sys_soc_notify_wake_event;
/**
* @brief Power Management Hook Interface
*
* @defgroup power_management_hook_interface Power Management Hook Interface
* @ingroup power_management_api
* @{
*/
/**
* @brief Function to disable wake event notification
*
* _sys_soc_resume() would be called from the ISR that caused exit from
* low power state. This function can be called at _sys_soc_suspend to disable
* this notification.
*/
static inline void _sys_soc_disable_wake_event_notification(void)
{
_sys_soc_notify_wake_event = 0;
}
/**
* @brief Hook function to notify exit from low power state
*
* The purpose of this function is to notify exit from
* low power states. The implementation of this function can vary
* depending on the soc specific boot flow.
*
* In the case of recovery from soc low power states like deep sleep,
* this function would switch cpu context to the execution point at the time
* system entered the soc low power state.
*
* In boot flows where this function gets called even at cold boot, the
* function should return immediately.
*
* Wake event notification:
* This function would also be called from the ISR context of the event
* that caused exit from the low power state. This will be called immediately
* after interrupts are enabled. This is called to give a chance to do
* any operations before the kernel would switch tasks or processes nested
* interrupts. This is required for cpu low power states that would require
* interrupts to be enabled while entering low power states. e.g. C1 in x86. In
* those cases, the ISR would be invoked immediately after the event wakes up
* the CPU, before code following the CPU wait, gets a chance to execute. This
* can be ignored if no operation needs to be done at the wake event
* notification. Alternatively _sys_soc_disable_wake_event_notification() can
* be called in _sys_soc_suspend to disable this notification.
*
* @note A dedicated function may be created in future to notify wake
* events, instead of overloading this one.
*/
extern void _sys_soc_resume(void);
/**
* @brief Hook function to allow entry to low power state
*
* This function is called by the kernel when it is about to idle.
* It is passed the number of clock ticks that the kernel calculated
* as available time to idle.
*
* The implementation of this function is dependent on the soc specific
* components and the various schemes they support. Some implementations
* may choose to do device PM operations in this function, while others
* would not need to, because they would have done it at other places.
*
* Typically a wake event is set and the soc or cpu is put to any of the
* supported low power states. The wake event should be set to wake up
* the soc or cpu before the available idle time expires to avoid disrupting
* the kernel's scheduling.
*
* This function is entered with interrupts disabled. It should
* re-enable interrupts if it had entered a low power state.
*
* @param ticks the upcoming kernel idle time
*
* @retval SYS_PM_NOT_HANDLED If low power state was not entered.
* @retval SYS_PM_LOW_POWER_STATE If CPU low power state was entered.
* @retval SYS_PM_DEEP_SLEEP If SOC low power state was entered.
*/
extern int _sys_soc_suspend(int32_t ticks);
/**
* @}
*/
#endif /* CONFIG_SYS_POWER_MANAGEMENT */
#ifdef __cplusplus
}
#endif
#endif /* __INCpower */