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Commit 7de36b0a authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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PM / OPP: Parse 'opp-supported-hw' binding 



OPP bindings allow a platform to enable OPPs based on the version of the
hardware they are used for.

Add support to the OPP-core to parse these bindings, by introducing
dev_pm_opp_{set|put}_supported_hw() APIs.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Tested-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent dc4e7b1f

drivers/base/power/opp/core.c

+148 −0
Original line number Diff line number Diff line
@@ -559,6 +559,9 @@ static void _remove_device_opp(struct device_opp *dev_opp) 
	if (!list_empty(&dev_opp->opp_list))

		return;



	if (dev_opp->supported_hw)

		return;



	list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,

				    node);
@@ -833,6 +836,145 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev) 
	return 0;

}



/**

 * dev_pm_opp_set_supported_hw() - Set supported platforms

 * @dev: Device for which supported-hw has to be set.

 * @versions: Array of hierarchy of versions to match.

 * @count: Number of elements in the array.

 *

 * This is required only for the V2 bindings, and it enables a platform to

 * specify the hierarchy of versions it supports. OPP layer will then enable

 * OPPs, which are available for those versions, based on its 'opp-supported-hw'

 * property.

 *

 * Locking: The internal device_opp and opp structures are RCU protected.

 * Hence this function internally uses RCU updater strategy with mutex locks

 * to keep the integrity of the internal data structures. Callers should ensure

 * that this function is *NOT* called under RCU protection or in contexts where

 * mutex cannot be locked.

 */

int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,

				unsigned int count)

{

	struct device_opp *dev_opp;

	int ret = 0;



	/* Hold our list modification lock here */

	mutex_lock(&dev_opp_list_lock);



	dev_opp = _add_device_opp(dev);

	if (!dev_opp) {

		ret = -ENOMEM;

		goto unlock;

	}



	/* Make sure there are no concurrent readers while updating dev_opp */

	WARN_ON(!list_empty(&dev_opp->opp_list));



	/* Do we already have a version hierarchy associated with dev_opp? */

	if (dev_opp->supported_hw) {

		dev_err(dev, "%s: Already have supported hardware list\n",

			__func__);

		ret = -EBUSY;

		goto err;

	}



	dev_opp->supported_hw = kmemdup(versions, count * sizeof(*versions),

					GFP_KERNEL);

	if (!dev_opp->supported_hw) {

		ret = -ENOMEM;

		goto err;

	}



	dev_opp->supported_hw_count = count;

	mutex_unlock(&dev_opp_list_lock);

	return 0;



err:

	_remove_device_opp(dev_opp);

unlock:

	mutex_unlock(&dev_opp_list_lock);



	return ret;

}

EXPORT_SYMBOL_GPL(dev_pm_opp_set_supported_hw);



/**

 * dev_pm_opp_put_supported_hw() - Releases resources blocked for supported hw

 * @dev: Device for which supported-hw has to be set.

 *

 * This is required only for the V2 bindings, and is called for a matching

 * dev_pm_opp_set_supported_hw(). Until this is called, the device_opp structure

 * will not be freed.

 *

 * Locking: The internal device_opp and opp structures are RCU protected.

 * Hence this function internally uses RCU updater strategy with mutex locks

 * to keep the integrity of the internal data structures. Callers should ensure

 * that this function is *NOT* called under RCU protection or in contexts where

 * mutex cannot be locked.

 */

void dev_pm_opp_put_supported_hw(struct device *dev)

{

	struct device_opp *dev_opp;



	/* Hold our list modification lock here */

	mutex_lock(&dev_opp_list_lock);



	/* Check for existing list for 'dev' first */

	dev_opp = _find_device_opp(dev);

	if (IS_ERR(dev_opp)) {

		dev_err(dev, "Failed to find dev_opp: %ld\n", PTR_ERR(dev_opp));

		goto unlock;

	}



	/* Make sure there are no concurrent readers while updating dev_opp */

	WARN_ON(!list_empty(&dev_opp->opp_list));



	if (!dev_opp->supported_hw) {

		dev_err(dev, "%s: Doesn't have supported hardware list\n",

			__func__);

		goto unlock;

	}



	kfree(dev_opp->supported_hw);

	dev_opp->supported_hw = NULL;

	dev_opp->supported_hw_count = 0;



	/* Try freeing device_opp if this was the last blocking resource */

	_remove_device_opp(dev_opp);



unlock:

	mutex_unlock(&dev_opp_list_lock);

}

EXPORT_SYMBOL_GPL(dev_pm_opp_put_supported_hw);



static bool _opp_is_supported(struct device *dev, struct device_opp *dev_opp,

			      struct device_node *np)

{

	unsigned int count = dev_opp->supported_hw_count;

	u32 version;

	int ret;



	if (!dev_opp->supported_hw)

		return true;



	while (count--) {

		ret = of_property_read_u32_index(np, "opp-supported-hw", count,

						 &version);

		if (ret) {

			dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",

				 __func__, count, ret);

			return false;

		}



		/* Both of these are bitwise masks of the versions */

		if (!(version & dev_opp->supported_hw[count]))

			return false;

	}



	return true;

}



/**

 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)

 * @dev:	device for which we do this operation
@@ -879,6 +1021,12 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np) 
		goto free_opp;

	}



	/* Check if the OPP supports hardware's hierarchy of versions or not */

	if (!_opp_is_supported(dev, dev_opp, np)) {

		dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);

		goto free_opp;

	}



	/*

	 * Rate is defined as an unsigned long in clk API, and so casting

	 * explicitly to its type. Must be fixed once rate is 64 bit

drivers/base/power/opp/opp.h

+5 −0
Original line number Diff line number Diff line
@@ -129,6 +129,8 @@ struct device_list_opp { 
 * @clock_latency_ns_max: Max clock latency in nanoseconds.

 * @shared_opp: OPP is shared between multiple devices.

 * @suspend_opp: Pointer to OPP to be used during device suspend.

 * @supported_hw: Array of version number to support.

 * @supported_hw_count: Number of elements in supported_hw array.

 * @dentry:	debugfs dentry pointer of the real device directory (not links).

 * @dentry_name: Name of the real dentry.

 *
@@ -153,6 +155,9 @@ struct device_opp { 
	bool shared_opp;

	struct dev_pm_opp *suspend_opp;



	unsigned int *supported_hw;

	unsigned int supported_hw_count;



#ifdef CONFIG_DEBUG_FS

	struct dentry *dentry;

	char dentry_name[NAME_MAX];

include/linux/pm_opp.h

+13 −0
Original line number Diff line number Diff line
@@ -55,6 +55,9 @@ int dev_pm_opp_enable(struct device *dev, unsigned long freq); 
int dev_pm_opp_disable(struct device *dev, unsigned long freq);



struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev);

int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,

				unsigned int count);

void dev_pm_opp_put_supported_hw(struct device *dev);

#else

static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)

{
@@ -129,6 +132,16 @@ static inline struct srcu_notifier_head *dev_pm_opp_get_notifier( 
{

	return ERR_PTR(-EINVAL);

}



static inline int dev_pm_opp_set_supported_hw(struct device *dev,

					      const u32 *versions,

					      unsigned int count)

{

	return -EINVAL;

}



static inline void dev_pm_opp_put_supported_hw(struct device *dev) {}



#endif		/* CONFIG_PM_OPP */



#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)