include/linux/pm.h

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3  *  pm.h - Power management interface
63  * struct dev_pm_ops - device PM callbacks.
70  *	registration of a child already in progress), it may return -EAGAIN, so
71  *	that the PM core can execute it once again (e.g. after a new child has
77  *	used to indicate to the PM core to leave the device in runtime suspend
78  *	if applicable.  Namely, if @prepare() returns a positive number, the PM
80  *	runtime-suspended and it may be left in that state during the entire
85  *	The PM core executes subsystem-level @prepare() for all devices before
101  *	of the other devices that the PM core has unsuccessfully attempted to
103  *	The PM core executes subsystem-level @complete() after it has executed
117  *	depends on the device's subsystem (PM domain, device type, class or bus
118  *	type), but generally the device must be quiescent after subsystem-level
120  *	Subsystem-level @suspend() is executed for all devices after invoking
121  *	subsystem-level @prepare() for all of them.
131  *	requests (the device itself may be left in a low-power state, waiting
136  *	Subsystem-level @resume() is executed for all devices after invoking
137  *	subsystem-level @resume_noirq() for all of them.
143  * @freeze: Hibernation-specific, executed before creating a hibernation image.
146  *	(with the notable exception of the PCI bus type) expect the driver-level
149  *	Subsystem-level @freeze() is executed for all devices after invoking
150  *	subsystem-level @prepare() for all of them.
156  * @thaw: Hibernation-specific, executed after creating a hibernation image OR
161  *	Subsystem-level @thaw() is executed for all devices after invoking
162  *	subsystem-level @thaw_noirq() for all of them.  It also may be executed
168  * @poweroff: Hibernation-specific, executed after saving a hibernation image.
171  *	Subsystem-level @poweroff() is executed for all devices after invoking
172  *	subsystem-level @prepare() for all of them.
177  * @restore: Hibernation-specific, executed after restoring the contents of main
186  *	It generally is expected that the device will be in a low-power state
187  *	(appropriate for the target system sleep state) after subsystem-level
192  *	put the device into the low-power state and configure it to generate
224  *	This need not mean that the device should be put into a low-power state.
233  *	necessary, put the device into the full-power state and restore its
237  *	low-power state if all of the necessary conditions are satisfied.
238  *	Check these conditions, and return 0 if it's appropriate to let the PM
244  * internal transitions to various low-power modes which are transparent
250  * callbacks are involved.  First, the PM core executes callbacks provided by PM
251  * domains, device types, classes and bus types.  They are the subsystem-level
254  * have to collaborate with the subsystem-level callbacks to achieve the goals
260  * @resume_noirq(), @thaw_noirq(), and @restore_noirq(), do not cause the PM
266  * allow the PM core to be modified in the future, so that it can avoid
276  * Again, as a rule these callbacks are executed by the PM core for subsystems
277  * (PM domains, device types, classes and bus types) and the subsystem-level
445  * Use this for defining a set of PM operations to be used in all situations
446  * (system suspend, hibernation or runtime PM).
448  * be different from the corresponding runtime PM callbacks, .runtime_suspend(),
481  * The following PM_EVENT_ messages are defined for the internal use of the PM
483  * hibernation code to convey the necessary information to the device PM core
488  * FREEZE	System is going to hibernate, call ->prepare() and ->freeze()
491  * SUSPEND	System is going to suspend, call ->prepare() and ->suspend()
494  * HIBERNATE	Hibernation image has been saved, call ->prepare() and
495  *		->poweroff() for all devices.
498  *		hibernation image, call ->prepare() and ->freeze() for all
501  * RESUME	System is resuming, call ->resume() and ->complete() for all
504  * THAW		Hibernation image has been created, call ->thaw() and
505  *		->complete() for all devices.
508  *		image, call ->restore() and ->complete() for all devices.
512  *		->thaw() and ->complete() for all devices.
515  * kernel subsystems.  They are never issued by the PM core.
521  * REMOTE_WAKEUP	Remote-wakeup request was received from the device.
530 #define PM_EVENT_INVALID	(-1)
575  * Device run-time power management status.
577  * These status labels are used internally by the PM core to indicate the
578  * current status of a device with respect to the PM core operations.  They do
583  *			bus type's ->runtime_resume() callback has completed
586  * RPM_SUSPENDED	Device bus type's ->runtime_suspend() callback has
590  * RPM_RESUMING		Device bus type's ->runtime_resume() callback is being
593  * RPM_SUSPENDING	Device bus type's ->runtime_suspend() callback is being
598 	RPM_INVALID = -1,
606  * Device run-time power management request types.
610  * RPM_REQ_IDLE		Run the device bus type's ->runtime_idle() callback
612  * RPM_REQ_SUSPEND	Run the device bus type's ->runtime_suspend() callback
617  * RPM_REQ_RESUME	Run the device bus type's ->runtime_resume() callback
651  * NO_DIRECT_COMPLETE: Do not apply direct-complete optimization to the device.
652  * SMART_PREPARE: Take the driver ->prepare callback return value into account.
656  * See Documentation/driver-api/pm/devices.rst for details.
667 	bool			in_dpm_list:1;	/* Owned by the PM core */
668 	bool			is_prepared:1;	/* Owned by the PM core */
673 	bool			early_init:1;	/* Owned by the PM core */
674 	bool			direct_complete:1;	/* Owned by the PM core */
683 	bool			no_pm_callbacks:1;	/* Owned by the PM core */
684 	bool			async_in_progress:1;	/* Owned by the PM core */
685 	bool			must_resume:1;		/* Owned by the PM core */
730  * struct dev_pm_domain - power management domain representation.
735  * @activate: Called before executing probe routines for bus types and drivers.
741  * hibernation, system resume and during runtime PM transitions instead of
742  * subsystem-level and driver-level callbacks.
756  * suspend framework, based on the ->suspend() and ->resume() callbacks common
769  *		a power-off reset, or it may have maintained state from the
777  * about how to quiesce that are specific to the bus or the device's type.
798  * A minimally power-aware driver treats all messages as SUSPEND, fully
799  * reinitializes its device during resume() -- whether or not it was reset
800  * during the suspend/resume cycle -- and can't issue wakeup events.
802  * More power-aware drivers may also use low power states at runtime as
804  * be able to use wakeup events to exit from runtime low-power states,
805  * or from system low-power states such as standby or suspend-to-RAM.