Power management

Collaboration diagram for Power management:

Data Structures
struct	pm_lock_t

Macros
#define	PM_LOCK_INIT(l, pm, cb, d)
#define	DECLARE_PM_LOCK(l, pm, cb, d)   static struct pm_lock_t pm = PM_LOCK_INIT(l, pm, cb, d)
#define	PM_LOCK(pm)   pm_lock(&pm)
#define	PM_UNLOCK(pm)   pm_unlock(&pm)
#define	PM_AUTO_LOCK(l)

Enumerations

Functions
void	pm_relax (void)
void	pm_wakeup (void)
void	pm_lock (struct pm_lock_t *pm)
void	pm_unlock (struct pm_lock_t *pm)
enum pm_level_t	pm_waterlevel (void)

Detailed Description

EVE power management framework

Macro Definition Documentation

#define PM_LOCK_INIT	(		l,
			pm,
			cb,
			d
	)

Value:

{                                   \
      .next = NULL,                     \
      .level = l,                       \
      .ready_cb = cb,                   \
      .data = d,                        \
      .locked = 0,                      \
    }

Initializes a power lock structure.

The macro is used to initialize a power lock structure instance.

Parameters

l	power level
pm	power lock structure
cb	user callback to be called before the system goes suspend
d	data for the user callback

Usage:

struct pm_lock_t MyConstLatPowerLock = PM_LOCK_INIT(PM_LEVEL_CONSTLAT, MyConstLatPowerLock, NULL, 0);

Definition at line 195 of file pm.h.

#define DECLARE_PM_LOCK	(		l,
			pm,
			cb,
			d
	)		static struct pm_lock_t pm = PM_LOCK_INIT(l, pm, cb, d)

Declares a power lock structure instance

Parameters

l	power level
pm	power lock structure
cb	user callback to be called before the system goes suspend
d	data for the user callback

Usage:

DECLARE_PM_LOCK(PM_LEVEL_CONSTLAT, MyConstLatPowerLock, NULL, 0);
// The above line is an equivalint of
struct pm_lock_t MyConstLatPowerLock = PM_LOCK_INIT(PM_LEVEL_CONSTLAT, MyConstLatPowerLock, NULL, 0);

Definition at line 210 of file pm.h.

#define PM_LOCK

(

pm

)

pm_lock(&pm)

Request the power level

The macro is used to request power at the given power level.

Parameters

pm	power lock structure

Usage:

PM_LOCK(MyConstLatPowerLock);

Definition at line 203 of file pm.h.

Referenced by clock_delay_usec(), and clock_wait().

#define PM_UNLOCK

(

pm

)

pm_unlock(&pm)

Release the power

The macro is used to release previously taken power request at the given power level.

If the power lock structure provides a user-defined callback, the PM_UNLOCK() puts the structure into a linked list of unlocked requests, waiting for suspend. During the following suspend (pm_relax()), the list is traversed and the callbacks are called by the framework. The callbacks can prevent system from suspend by returning false.

Parameters

pm	power lock structure

Usage:

PM_UNLOCK(MyConstLatPowerLock);

Definition at line 204 of file pm.h.

Referenced by clock_delay_usec(), and clock_wait().

#define PM_AUTO_LOCK

(

l

)

Value:

struct pm_lock_t EvePmAutoLock __attribute__((cleanup(pm_unlock))); \
      do { EvePmAutoLock = (struct pm_lock_t) PM_LOCK_INIT(l, EvePmAutoLock, NULL, 0); } while (0)

Declares an anonymous auto lock, which holds power request in the auto variable visibility block

Parameters

l	power level

Usage:

{
  PM_AUTO_LOCK(PM_LEVEL_CONSTLAT);
  clock_delay(MS_TO_TICKS(10)); // The delay will be executed at at least CONSTLAT level.
}
// The lock is released here

Definition at line 205 of file pm.h.

Enumeration Type Documentation

enum pm_level_t

System power level.

Enumerator
PM_LEVEL_RUNNING	System is kept spinning when idle. Høyest power consumption.
PM_LEVEL_CONSTLAT	System ON, Constant latency mode.
PM_LEVEL_LOWPWR	System ON, Low power mode.
PM_LEVEL_CLOCKLESS	System ON, Low power mode, 32 kHz clock off.
PM_LEVEL_OFF	System OFF.
PM_LEVEL__COUNT	Number of elements in the pm_level_t enum.

Definition at line 57 of file pm.h.

Function Documentation

void pm_relax

(

void

)

Enters the lowest power level.

Before entring low-power mode, pm_relax() traverses via the list of lock structures, registered by PM_UNLOCK(), and calls user-defined callbacks. If a callback returns false, then the ongoing suspend is cancelled.

While interrupt handling is performed, pm_relax() does not return to the operating system until a wakeup is requested by pm_wakeup() call.

Referenced by clock_delay_usec(), and clock_wait().

void pm_wakeup

(

void

)

Wakeups the system from suspend state.

Interrupt handlers must call this function if they want to wake up operating system from suspend state.

Referenced by clock_wait(), process_poll(), and process_post().

void pm_lock

(

struct pm_lock_t *

pm

)

Restrict deepness of suspend to the given power level

Parameters

pm	pointer to the power lock structure

void pm_unlock

(

struct pm_lock_t *

pm

)

Release a previously taken power lock

Parameters

pm	pointer to the power lock structure

enum pm_level_t pm_waterlevel

(

void

)

Query the level the system can be put down to sleep taking in mind currently taken locks.