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power_mgmt: APIs for devices to signal busy

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Certain Low power SOC states (e.g. deep sleep)  will result in device
IP blocks losing state. In such a scenario it can be useful to have
a mechanism for devices (driver code) to signal the power manager /
policy that they are in the middle of a transaction.

We expect the device driver code to make a call to
device_busy_set(device *) before initiating a transaction and
device_busy_clear(device *) on completion. It is expected that device
driver developers will add this as necessary in their drivers.

Further an API is provided  for power manager application / policy to
check this. Based on this the power manager / policy can  decide
whether or not to go into a particular power state.

Change-Id: I0fedd90b98e182cd41b53c7f9e08655532822faa
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
This commit is contained in:
Jithu Joseph 2016-04-08 12:38:57 -07:00 • committed by Anas Nashif
commit 592882e5f4
4 changed files with 110 additions and 1 deletions
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43
include/device.h
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@ -304,6 +304,25 @@ struct device {
void _sys_device_do_config_level(int level);
struct device* device_get_binding(char *name);
/**
* @brief Indicate that the device is in the middle of a transaction
*
* Called by a device driver to indicate that it is in the middle of a
* transaction.
*
* @param busy_dev Pointer to device structure of the driver instance.
*/
void device_busy_set(struct device *busy_dev);
/**
* @brief Indicate that the device has completed its transaction
*
* Called by a device driver to indicate the end of a transaction.
*
* @param busy_dev Pointer to device structure of the driver instance.
*/
void device_busy_clear(struct device *busy_dev);
#ifdef CONFIG_DEVICE_POWER_MANAGEMENT
/**
* Device PM functions
@ -370,6 +389,30 @@ static inline int device_resume(struct device *device, int pm_policy)
*/
void device_list_get(struct device **device_list, int *device_count);
/**
* @brief Check if any device is in the middle of a transaction
*
* Called by an application to see if any device is in the middle
* of a critical transaction that cannot be interrupted.
*
* @retval 0 if no device is busy
* @retval -EBUSY if any device is busy
*/
int device_any_busy_check(void);
/**
* @brief Check if a specific device is in the middle of a transaction
*
* Called by an application to see if a particular device is in the
* middle of a critical transaction that cannot be interrupted.
*
* @param chk_dev Pointer to device structure of the specific device driver
* the caller is interested in.
* @retval 0 if the device is not busy
* @retval -EBUSY if the device is busy
*/
int device_busy_check(struct device *chk_dev);
#endif
/**