Commit 7811ac27 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

Merge branch 'pm-devfreq' into pm-for-linus 

* pm-devfreq:
  PM / devfreq: Add basic governors
  PM / devfreq: Add common sysfs interfaces
  PM: Introduce devfreq: generic DVFS framework with device-specific OPPs
  PM / OPP: Add OPP availability change notifier.
parents 9696cc90 ce26c5bb

Documentation/ABI/testing/sysfs-class-devfreq

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What:		/sys/class/devfreq/.../

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		Provide a place in sysfs for the devfreq objects.

		This allows accessing various devfreq specific variables.

		The name of devfreq object denoted as ... is same as the

		name of device using devfreq.



What:		/sys/class/devfreq/.../governor

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		The /sys/class/devfreq/.../governor shows the name of the

		governor used by the corresponding devfreq object.



What:		/sys/class/devfreq/.../cur_freq

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		The /sys/class/devfreq/.../cur_freq shows the current

		frequency of the corresponding devfreq object.



What:		/sys/class/devfreq/.../central_polling

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		The /sys/class/devfreq/.../central_polling shows whether

		the devfreq ojbect is using devfreq-provided central

		polling mechanism or not.



What:		/sys/class/devfreq/.../polling_interval

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		The /sys/class/devfreq/.../polling_interval shows and sets

		the requested polling interval of the corresponding devfreq

		object. The values are represented in ms. If the value is

		less than 1 jiffy, it is considered to be 0, which means

		no polling. This value is meaningless if the governor is

		not polling; thus. If the governor is not using

		devfreq-provided central polling

		(/sys/class/devfreq/.../central_polling is 0), this value

		may be useless.



What:		/sys/class/devfreq/.../userspace/set_freq

Date:		September 2011

Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Description:

		The /sys/class/devfreq/.../userspace/set_freq shows and

		sets the requested frequency for the devfreq object if

		userspace governor is in effect.

drivers/Kconfig

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@@ -130,4 +130,6 @@ source "drivers/iommu/Kconfig" 


source "drivers/virt/Kconfig"



source "drivers/devfreq/Kconfig"



endmenu

drivers/Makefile

+2 −0
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@@ -127,3 +127,5 @@ obj-$(CONFIG_IOMMU_SUPPORT) += iommu/ 


# Virtualization drivers

obj-$(CONFIG_VIRT_DRIVERS)	+= virt/



obj-$(CONFIG_PM_DEVFREQ)	+= devfreq/

drivers/base/power/opp.c

+30 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ struct opp { 
 *		RCU usage: nodes are not modified in the list of device_opp,

 *		however addition is possible and is secured by dev_opp_list_lock

 * @dev:	device pointer

 * @head:	notifier head to notify the OPP availability changes.

 * @opp_list:	list of opps

 *

 * This is an internal data structure maintaining the link to opps attached to
@@ -83,6 +84,7 @@ struct device_opp { 
	struct list_head node;



	struct device *dev;

	struct srcu_notifier_head head;

	struct list_head opp_list;

};
@@ -404,6 +406,7 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) 
		}



		dev_opp->dev = dev;

		srcu_init_notifier_head(&dev_opp->head);

		INIT_LIST_HEAD(&dev_opp->opp_list);



		/* Secure the device list modification */
@@ -428,6 +431,11 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) 
	list_add_rcu(&new_opp->node, head);

	mutex_unlock(&dev_opp_list_lock);



	/*

	 * Notify the changes in the availability of the operable

	 * frequency/voltage list.

	 */

	srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp);

	return 0;

}
@@ -504,6 +512,14 @@ static int opp_set_availability(struct device *dev, unsigned long freq, 
	mutex_unlock(&dev_opp_list_lock);

	synchronize_rcu();



	/* Notify the change of the OPP availability */

	if (availability_req)

		srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ENABLE,

					 new_opp);

	else

		srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE,

					 new_opp);



	/* clean up old opp */

	new_opp = opp;

	goto out;
@@ -643,3 +659,17 @@ void opp_free_cpufreq_table(struct device *dev, 
	*table = NULL;

}

#endif		/* CONFIG_CPU_FREQ */



/**

 * opp_get_notifier() - find notifier_head of the device with opp

 * @dev:	device pointer used to lookup device OPPs.

 */

struct srcu_notifier_head *opp_get_notifier(struct device *dev)

{

	struct device_opp *dev_opp = find_device_opp(dev);



	if (IS_ERR(dev_opp))

		return ERR_PTR(PTR_ERR(dev_opp)); /* matching type */



	return &dev_opp->head;

}

drivers/devfreq/Kconfig

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config ARCH_HAS_DEVFREQ

	bool

	depends on ARCH_HAS_OPP

	help

	  Denotes that the architecture supports DEVFREQ. If the architecture

	  supports multiple OPP entries per device and the frequency of the

	  devices with OPPs may be altered dynamically, the architecture

	  supports DEVFREQ.



menuconfig PM_DEVFREQ

	bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"

	depends on PM_OPP && ARCH_HAS_DEVFREQ

	help

	  With OPP support, a device may have a list of frequencies and

	  voltages available. DEVFREQ, a generic DVFS framework can be

	  registered for a device with OPP support in order to let the

	  governor provided to DEVFREQ choose an operating frequency

	  based on the OPP's list and the policy given with DEVFREQ.



	  Each device may have its own governor and policy. DEVFREQ can

	  reevaluate the device state periodically and/or based on the

	  OPP list changes (each frequency/voltage pair in OPP may be

	  disabled or enabled).



	  Like some CPUs with CPUFREQ, a device may have multiple clocks.

	  However, because the clock frequencies of a single device are

	  determined by the single device's state, an instance of DEVFREQ

	  is attached to a single device and returns a "representative"

	  clock frequency from the OPP of the device, which is also attached

	  to a device by 1-to-1. The device registering DEVFREQ takes the

	  responsiblity to "interpret" the frequency listed in OPP and

	  to set its every clock accordingly with the "target" callback

	  given to DEVFREQ.



if PM_DEVFREQ



comment "DEVFREQ Governors"



config DEVFREQ_GOV_SIMPLE_ONDEMAND

	bool "Simple Ondemand"

	help

	  Chooses frequency based on the recent load on the device. Works

	  similar as ONDEMAND governor of CPUFREQ does. A device with

	  Simple-Ondemand should be able to provide busy/total counter

	  values that imply the usage rate. A device may provide tuned

	  values to the governor with data field at devfreq_add_device().



config DEVFREQ_GOV_PERFORMANCE

	bool "Performance"

	help

	  Sets the frequency at the maximum available frequency.

	  This governor always returns UINT_MAX as frequency so that

	  the DEVFREQ framework returns the highest frequency available

	  at any time.



config DEVFREQ_GOV_POWERSAVE

	bool "Powersave"

	help

	  Sets the frequency at the minimum available frequency.

	  This governor always returns 0 as frequency so that

	  the DEVFREQ framework returns the lowest frequency available

	  at any time.



config DEVFREQ_GOV_USERSPACE

	bool "Userspace"

	help

	  Sets the frequency at the user specified one.

	  This governor returns the user configured frequency if there

	  has been an input to /sys/devices/.../power/devfreq_set_freq.

	  Otherwise, the governor does not change the frequnecy

	  given at the initialization.



comment "DEVFREQ Drivers"



endif # PM_DEVFREQ

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