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subsys: power: rework device runtime power management.
In order to reduce the overall system power consumption, we should suspend the devices which are idle or not being used while system is active or running. Currently there is device idle power management framework which intends to do that. But the implementation seems can only do get/put one after one and can't handle the concurrency, for example if multiple threads request for DEVICE_PM_ACTIVE_STATE concurrently, there is possibility polling the signal without reset and signal contention among multiple threads. And the disable function doesn't consider the ongoing transition. Further it doesn't consider the device dependency. So decide rework the implementation and rename it device runtime power management following the definition in zephyrproject-rtos#24228. The API rt_dpm_claim is trying to resume the device and protect any hardware transfer after this call by increasing the usage count. When there is concurrency with another claim or release, this API will pend the current thread to the wait_q until previous transition finished. The API rt_dpm_release is to release previous claim, forbid unexpected release. And no hardware operation depends on release, so release has asynchronous version. After the release, the parents of that device will also be considered automatically. And it can be decided by individual device to support device runtime power management or not by the API rt_dpm_enable/rt_dpm_disable. And also it's the device driver instead of this framework that decide how to define device not in use, it means device driver decide where to put rt_dpm_claim/rt_dpm_release, for example we can put them around transfer function for i2c, but for net device, maybe we can only put them around open/close or other similar place. Signed-off-by: Wentong Wu <wentong.wu@intel.com>
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| Original file line number | Diff line number | Diff line change |
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| /* | ||
| * Copyright (c) 2020 Intel corporation | ||
| * | ||
| * SPDX-License-Identifier: Apache-2.0 | ||
| */ | ||
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| #ifndef ZEPHYR_INCLUDE_POWER_RT_DPM_H | ||
| #define ZEPHYR_INCLUDE_POWER_RT_DPM_H | ||
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| #include <device.h> | ||
| #include <sys/atomic.h> | ||
| #include <kernel_structs.h> | ||
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| #ifdef __cplusplus | ||
| extern "C" { | ||
| #endif | ||
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| /** | ||
| * @brief Callbacks defined for device runtime power management. | ||
| * | ||
| * The post_resume/pre_suspend callbacks are used to do stuff without | ||
| * irq locked (e.g. states sync between driver and firmware). Device | ||
| * driver should take care all the possible errors during this irq | ||
| * unlocked period and the result will be indicated by the return value. | ||
| * | ||
| * The resume/suspend callbacks will do the real power/clock involved | ||
| * stuff with irq locked. The specific state devices will go completely | ||
| * depends on every device, resume/suspend is generic definition here. | ||
| * | ||
| * @retval 0 if successfully excute post_resume/pre_suspend. | ||
| * @retval -EIO if error happens during irq unlocked stage. | ||
| */ | ||
| struct rt_dpm_ops { | ||
| void (*resume)(struct device *dev); | ||
| void (*suspend)(struct device *dev); | ||
| int (*post_resume)(struct device *dev); | ||
| int (*pre_suspend)(struct device *dev); | ||
| }; | ||
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| /** | ||
| * @brief Structure used to do device runtime power management. | ||
| */ | ||
| struct rt_dpm { | ||
| /* device runtime pm state */ | ||
| int state; | ||
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| /* wait queue on which threads are pended | ||
| * because of the possible concurrency. | ||
| */ | ||
| _wait_q_t wait_q; | ||
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| /* work item used to do asynchronously state transition */ | ||
| struct k_work work; | ||
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| /* usage count of the device */ | ||
| atomic_t usage_count; | ||
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| struct k_spinlock lock; | ||
| struct rt_dpm_ops *ops; | ||
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| /* protected by spinlock so don't use atomic */ | ||
| unsigned int disable_count; | ||
| }; | ||
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| /** | ||
| * @brief Loop over parent for the given device. | ||
| */ | ||
| #define DEVICE_PARENT_FOREACH(dev, iterator) \ | ||
| for (struct device *iterator = dev; iterator != NULL; ) | ||
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| /** | ||
| * @brief Initialize device runtime power management. | ||
| * | ||
| * Initialize device runtime power management for the given device. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * @param is_suspend Initial state of given device. | ||
| */ | ||
| void rt_dpm_init(struct device *dev, bool is_suspend); | ||
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| /** | ||
| * @brief Enable device runtime power management. | ||
| * | ||
| * Enable device runtime power management for the given device. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| */ | ||
| void rt_dpm_enable(struct device *dev); | ||
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| /** | ||
| * @brief Disable device runtime power management. | ||
| * | ||
| * Disable device runtime power management for the given device. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| */ | ||
| void rt_dpm_disable(struct device *dev); | ||
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| /** | ||
| * @brief Claim a device to mark the device as being used. | ||
| * | ||
| * Claim the given device to make sure any device operation protected | ||
| * by the succeful claim is safe. Can't be used in ISRs. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * | ||
| * @retval 0 if successfully claimed the given device. | ||
| * @retval -EIO if error happens during device post resume. | ||
| * @retval -EACCES if disabled device runtime power management. | ||
| */ | ||
| int rt_dpm_claim(struct device *dev); | ||
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| /** | ||
| * @brief Release the given device. | ||
| * | ||
| * Synchronously decrease usage count of the given device and suspend | ||
| * that device if all the conditions satisfied, this function must be | ||
| * called after any claim happens, forbid asymmetric release. Can't be | ||
| * used in ISRs. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * | ||
| * @retval 0 if successfully release the given device. | ||
| * @retval -EIO if error happens during device suspend prepare. | ||
| * @retval -EACCES if disabled device runtime power management. | ||
| */ | ||
| int rt_dpm_release(struct device *dev); | ||
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| /** | ||
| * @brief Release the given device asynchronously. | ||
| * | ||
| * Decrease usage count of the given device and submit suspend request | ||
| * to work queue when usage count crossing 1 - 0 boundary. Can be used | ||
| * in ISRs. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * | ||
| * @retval 0 if successfully release the given device. | ||
| * @retval 1 if successfully submit the release request. | ||
| */ | ||
| int rt_dpm_release_async(struct device *dev); | ||
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| /** | ||
| * @brief Whether given device is in active state. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * | ||
| * @retval True if given device is in active state. | ||
| * @retval False if given device isn't in active state. | ||
| */ | ||
| bool rt_dpm_is_active_state(struct device *dev); | ||
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| /** | ||
| * @brief Whether given device is in suspended state. | ||
| * | ||
| * @param dev Pointer to the given device. | ||
| * | ||
| * @retval True if given device is in suspended state. | ||
| * @retval False if given device isn't in suspended state. | ||
| */ | ||
| bool rt_dpm_is_suspend_state(struct device *dev); | ||
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| #ifdef __cplusplus | ||
| } | ||
| #endif | ||
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| #endif |
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