Merge branches 'pm-qos', 'pm-opp' and 'pm-devfreq'

* pm-qos:
  PM / QoS: Use lockdep asserts to find missing hold of power.lock
  PM / QoS: Add debugfs support to view the list of constraints

* pm-opp:
  PM / OPP: Assert RCU lock in exported functions
  PM / OPP: Update kernel documentation
  PM / OPP: Ensure consistent naming of static functions
  PM / OPP: export dev_pm_opp_get_notifier

* pm-devfreq:
  PM / devfreq: event: Add documentation for exynos-ppmu devfreq-event driver
  devfreq: Fix build break of devfreq-event class
  PM / devfreq: event: Add devfreq_event class
  PM / devfreq: tegra: add devfreq driver for Tegra Activity Monitor

Documentation/devicetree/bindings/devfreq/event/exynos-ppmu.txt

+
+* Samsung Exynos PPMU (Platform Performance Monitoring Unit) device
+
+The Samsung Exynos SoC has PPMU (Platform Performance Monitoring Unit) for
+each IP. PPMU provides the primitive values to get performance data. These
+PPMU events provide information of the SoC's behaviors so that you may
+use to analyze system performance, to make behaviors visible and to count
+usages of each IP (DMC, CPU, RIGHTBUS, LEFTBUS, CAM interface, LCD, G3D, MFC).
+The Exynos PPMU driver uses the devfreq-event class to provide event data
+to various devfreq devices. The devfreq devices would use the event data when
+derterming the current state of each IP.
+
+Required properties:
+- compatible: Should be "samsung,exynos-ppmu".
+- reg: physical base address of each PPMU and length of memory mapped region.
+
+Optional properties:
+- clock-names : the name of clock used by the PPMU, "ppmu"
+- clocks : phandles for clock specified in "clock-names" property
+- #clock-cells: should be 1.
+
+Example1 : PPMU nodes in exynos3250.dtsi are listed below.
+
+		ppmu_dmc0: ppmu_dmc0@106a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106a0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_dmc1: ppmu_dmc1@106b0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106b0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_cpu: ppmu_cpu@106c0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x106c0000 0x2000>;
+			status = "disabled";
+		};
+
+		ppmu_rightbus: ppmu_rightbus@112a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x112a0000 0x2000>;
+			clocks = <&cmu CLK_PPMURIGHT>;
+			clock-names = "ppmu";
+			status = "disabled";
+		};
+
+		ppmu_leftbus: ppmu_leftbus0@116a0000 {
+			compatible = "samsung,exynos-ppmu";
+			reg = <0x116a0000 0x2000>;
+			clocks = <&cmu CLK_PPMULEFT>;
+			clock-names = "ppmu";
+			status = "disabled";
+		};
+
+Example2 : Events of each PPMU node in exynos3250-rinato.dts are listed below.
+
+	&ppmu_dmc0 {
+		status = "okay";
+
+		events {
+			ppmu_dmc0_3: ppmu-event3-dmc0 {
+				event-name = "ppmu-event3-dmc0";
+			};
+
+			ppmu_dmc0_2: ppmu-event2-dmc0 {
+				event-name = "ppmu-event2-dmc0";
+			};
+
+			ppmu_dmc0_1: ppmu-event1-dmc0 {
+				event-name = "ppmu-event1-dmc0";
+			};
+
+			ppmu_dmc0_0: ppmu-event0-dmc0 {
+				event-name = "ppmu-event0-dmc0";
+			};
+		};
+	};
+
+	&ppmu_dmc1 {
+		status = "okay";
+
+		events {
+			ppmu_dmc1_3: ppmu-event3-dmc1 {
+				event-name = "ppmu-event3-dmc1";
+			};
+		};
+	};
+
+	&ppmu_leftbus {
+		status = "okay";
+
+		events {
+			ppmu_leftbus_3: ppmu-event3-leftbus {
+				event-name = "ppmu-event3-leftbus";
+			};
+		};
+	};
+
+	&ppmu_rightbus {
+		status = "okay";
+
+		events {
+			ppmu_rightbus_3: ppmu-event3-rightbus {
+				event-name = "ppmu-event3-rightbus";
+			};
+		};
+	};

drivers/base/power/opp.c

@@ -117,20 +117,20 @@ do {									\
 } while (0)
 
 /**
- * find_device_opp() - find device_opp struct using device pointer
+ * _find_device_opp() - find device_opp struct using device pointer
  * @dev:	device pointer used to lookup device OPPs
  *
  * Search list of device OPPs for one containing matching device. Does a RCU
  * reader operation to grab the pointer needed.
  *
- * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or
+ * Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
  * -EINVAL based on type of error.
  *
  * Locking: This function must be called under rcu_read_lock(). device_opp
  * is a RCU protected pointer. This means that device_opp is valid as long
  * as we are under RCU lock.
  */
-static struct device_opp *find_device_opp(struct device *dev)
+static struct device_opp *_find_device_opp(struct device *dev)
 {
 	struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV);
 
@@ -153,7 +153,7 @@ static struct device_opp *find_device_opp(struct device *dev)
  * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
  * @opp:	opp for which voltage has to be returned for
  *
- * Return voltage in micro volt corresponding to the opp, else
+ * Return: voltage in micro volt corresponding to the opp, else
  * return 0
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
@@ -169,6 +169,8 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	struct dev_pm_opp *tmp_opp;
 	unsigned long v = 0;
 
+	opp_rcu_lockdep_assert();
+
 	tmp_opp = rcu_dereference(opp);
 	if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
 		pr_err("%s: Invalid parameters\n", __func__);
@@ -183,7 +185,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
  * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
  * @opp:	opp for which frequency has to be returned for
  *
- * Return frequency in hertz corresponding to the opp, else
+ * Return: frequency in hertz corresponding to the opp, else
  * return 0
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
@@ -199,6 +201,8 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 	struct dev_pm_opp *tmp_opp;
 	unsigned long f = 0;
 
+	opp_rcu_lockdep_assert();
+
 	tmp_opp = rcu_dereference(opp);
 	if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
 		pr_err("%s: Invalid parameters\n", __func__);
@@ -213,7 +217,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
  * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
  * @dev:	device for which we do this operation
  *
- * This function returns the number of available opps if there are any,
+ * Return: This function returns the number of available opps if there are any,
  * else returns 0 if none or the corresponding error value.
  *
  * Locking: This function takes rcu_read_lock().
@@ -226,7 +230,7 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 
 	rcu_read_lock();
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		count = PTR_ERR(dev_opp);
 		dev_err(dev, "%s: device OPP not found (%d)\n",
@@ -251,9 +255,9 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
  * @freq:		frequency to search for
  * @available:		true/false - match for available opp
  *
- * Searches for exact match in the opp list and returns pointer to the matching
- * opp if found, else returns ERR_PTR in case of error and should be handled
- * using IS_ERR. Error return values can be:
+ * Return: Searches for exact match in the opp list and returns pointer to the
+ * matching opp if found, else returns ERR_PTR in case of error and should
+ * be handled using IS_ERR. Error return values can be:
  * EINVAL:	for bad pointer
  * ERANGE:	no match found for search
  * ENODEV:	if device not found in list of registered devices
@@ -280,7 +284,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 
 	opp_rcu_lockdep_assert();
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
 		dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
@@ -307,7 +311,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
  * Search for the matching ceil *available* OPP from a starting freq
  * for a device.
  *
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
  * ERR_PTR in case of error and should be handled using IS_ERR. Error return
  * values can be:
  * EINVAL:	for bad pointer
@@ -333,7 +337,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp);
 
@@ -357,7 +361,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
  * Search for the matching floor *available* OPP from a starting freq
  * for a device.
  *
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
  * ERR_PTR in case of error and should be handled using IS_ERR. Error return
  * values can be:
  * EINVAL:	for bad pointer
@@ -383,7 +387,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp);
 
@@ -403,7 +407,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
 
-static struct device_opp *add_device_opp(struct device *dev)
+/**
+ * _add_device_opp() - Allocate a new device OPP table
+ * @dev:	device for which we do this operation
+ *
+ * New device node which uses OPPs - used when multiple devices with OPP tables
+ * are maintained.
+ *
+ * Return: valid device_opp pointer if success, else NULL.
+ */
+static struct device_opp *_add_device_opp(struct device *dev)
 {
 	struct device_opp *dev_opp;
 
@@ -424,8 +437,35 @@ static struct device_opp *add_device_opp(struct device *dev)
 	return dev_opp;
 }
 
-static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
-				  unsigned long u_volt, bool dynamic)
+/**
+ * _opp_add_dynamic() - Allocate a dynamic OPP.
+ * @dev:	device for which we do this operation
+ * @freq:	Frequency in Hz for this OPP
+ * @u_volt:	Voltage in uVolts for this OPP
+ * @dynamic:	Dynamically added OPPs.
+ *
+ * This function adds an opp definition to the opp list and returns status.
+ * The opp is made available by default and it can be controlled using
+ * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
+ *
+ * NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
+ * freed by of_free_opp_table.
+ *
+ * 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.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ */
+static int _opp_add_dynamic(struct device *dev, unsigned long freq,
+			    long u_volt, bool dynamic)
 {
 	struct device_opp *dev_opp = NULL;
 	struct dev_pm_opp *opp, *new_opp;
@@ -449,9 +489,9 @@ static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
 	new_opp->dynamic = dynamic;
 
 	/* Check for existing list for 'dev' */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
-		dev_opp = add_device_opp(dev);
+		dev_opp = _add_device_opp(dev);
 		if (!dev_opp) {
 			ret = -ENOMEM;
 			goto free_opp;
@@ -519,33 +559,52 @@ static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
  * mutex cannot be locked.
  *
  * Return:
- * 0:		On success OR
+ * 0		On success OR
  *		Duplicate OPPs (both freq and volt are same) and opp->available
- * -EEXIST:	Freq are same and volt are different OR
+ * -EEXIST	Freq are same and volt are different OR
  *		Duplicate OPPs (both freq and volt are same) and !opp->available
- * -ENOMEM:	Memory allocation failure
+ * -ENOMEM	Memory allocation failure
  */
 int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
 {
-	return dev_pm_opp_add_dynamic(dev, freq, u_volt, true);
+	return _opp_add_dynamic(dev, freq, u_volt, true);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_add);
 
-static void kfree_opp_rcu(struct rcu_head *head)
+/**
+ * _kfree_opp_rcu() - Free OPP RCU handler
+ * @head:	RCU head
+ */
+static void _kfree_opp_rcu(struct rcu_head *head)
 {
 	struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
 
 	kfree_rcu(opp, rcu_head);
 }
 
-static void kfree_device_rcu(struct rcu_head *head)
+/**
+ * _kfree_device_rcu() - Free device_opp RCU handler
+ * @head:	RCU head
+ */
+static void _kfree_device_rcu(struct rcu_head *head)
 {
 	struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
 
 	kfree_rcu(device_opp, rcu_head);
 }
 
-static void __dev_pm_opp_remove(struct device_opp *dev_opp,
+/**
+ * _opp_remove()  - Remove an OPP from a table definition
+ * @dev_opp:	points back to the device_opp struct this opp belongs to
+ * @opp:	pointer to the OPP to remove
+ *
+ * This function removes an opp definition from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * It is assumed that the caller holds required mutex for an RCU updater
+ * strategy.
+ */
+static void _opp_remove(struct device_opp *dev_opp,
 			struct dev_pm_opp *opp)
 {
 	/*
@@ -554,12 +613,12 @@ static void __dev_pm_opp_remove(struct device_opp *dev_opp,
 	 */
 	srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
 	list_del_rcu(&opp->node);
-	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu);
+	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
 	if (list_empty(&dev_opp->opp_list)) {
 		list_del_rcu(&dev_opp->node);
 		call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
-			  kfree_device_rcu);
+			  _kfree_device_rcu);
 	}
 }
 
@@ -569,6 +628,12 @@ static void __dev_pm_opp_remove(struct device_opp *dev_opp,
  * @freq:	OPP to remove with matching 'freq'
  *
  * This function removes an opp from the opp list.
+ *
+ * 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_remove(struct device *dev, unsigned long freq)
 {
@@ -579,7 +644,7 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 	/* Hold our list modification lock here */
 	mutex_lock(&dev_opp_list_lock);
 
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp))
 		goto unlock;
 
@@ -596,14 +661,14 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 		goto unlock;
 	}
 
-	__dev_pm_opp_remove(dev_opp, opp);
+	_opp_remove(dev_opp, opp);
 unlock:
 	mutex_unlock(&dev_opp_list_lock);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
 
 /**
- * opp_set_availability() - helper to set the availability of an opp
+ * _opp_set_availability() - helper to set the availability of an opp
  * @dev:		device for which we do this operation
  * @freq:		OPP frequency to modify availability
  * @availability_req:	availability status requested for this opp
@@ -611,7 +676,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
  * Set the availability of an OPP with an RCU operation, opp_{enable,disable}
  * share a common logic which is isolated here.
  *
- * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
  * copy operation, returns 0 if no modifcation was done OR modification was
  * successful.
  *
@@ -621,7 +686,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
  */
-static int opp_set_availability(struct device *dev, unsigned long freq,
+static int _opp_set_availability(struct device *dev, unsigned long freq,
 				 bool availability_req)
 {
 	struct device_opp *dev_opp;
@@ -638,7 +703,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 	mutex_lock(&dev_opp_list_lock);
 
 	/* Find the device_opp */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		r = PTR_ERR(dev_opp);
 		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
@@ -668,7 +733,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 
 	list_replace_rcu(&opp->node, &new_opp->node);
 	mutex_unlock(&dev_opp_list_lock);
-	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu);
+	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
 	/* Notify the change of the OPP availability */
 	if (availability_req)
@@ -700,10 +765,14 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
  * integrity of the internal data structures. Callers should ensure that
  * this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modifcation was done OR modification was
+ * successful.
  */
 int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 {
-	return opp_set_availability(dev, freq, true);
+	return _opp_set_availability(dev, freq, true);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
 
@@ -722,26 +791,41 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
  * integrity of the internal data structures. Callers should ensure that
  * this function is *NOT* called under RCU protection or in contexts where
  * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modifcation was done OR modification was
+ * successful.
  */
 int dev_pm_opp_disable(struct device *dev, unsigned long freq)
 {
-	return opp_set_availability(dev, freq, false);
+	return _opp_set_availability(dev, freq, false);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
 
 /**
  * dev_pm_opp_get_notifier() - find notifier_head of the device with opp
  * @dev:	device pointer used to lookup device OPPs.
+ *
+ * Return: pointer to  notifier head if found, otherwise -ENODEV or
+ * -EINVAL based on type of error casted as pointer. value must be checked
+ *  with IS_ERR to determine valid pointer or error result.
+ *
+ * Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
  */
 struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
 {
-	struct device_opp *dev_opp = find_device_opp(dev);
+	struct device_opp *dev_opp = _find_device_opp(dev);
 
 	if (IS_ERR(dev_opp))
 		return ERR_CAST(dev_opp); /* matching type */
 
 	return &dev_opp->srcu_head;
 }
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
 
 #ifdef CONFIG_OF
 /**
@@ -749,6 +833,22 @@ struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
  * @dev:	device pointer used to lookup device OPPs.
  *
  * Register the initial OPP table with the OPP library for given device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly 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.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -ENODEV	when 'operating-points' property is not found or is invalid data
+ *		in device node.
+ * -ENODATA	when empty 'operating-points' property is found
  */
 int of_init_opp_table(struct device *dev)
 {
@@ -777,7 +877,7 @@ int of_init_opp_table(struct device *dev)
 		unsigned long freq = be32_to_cpup(val++) * 1000;
 		unsigned long volt = be32_to_cpup(val++);
 
-		if (dev_pm_opp_add_dynamic(dev, freq, volt, false))
+		if (_opp_add_dynamic(dev, freq, volt, false))
 			dev_warn(dev, "%s: Failed to add OPP %ld\n",
 				 __func__, freq);
 		nr -= 2;
@@ -792,6 +892,12 @@ EXPORT_SYMBOL_GPL(of_init_opp_table);
  * @dev:	device pointer used to lookup device OPPs.
  *
  * Free OPPs created using static entries present in DT.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly 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 of_free_opp_table(struct device *dev)
 {
@@ -799,7 +905,7 @@ void of_free_opp_table(struct device *dev)
 	struct dev_pm_opp *opp, *tmp;
 
 	/* Check for existing list for 'dev' */
-	dev_opp = find_device_opp(dev);
+	dev_opp = _find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int error = PTR_ERR(dev_opp);
 		if (error != -ENODEV)
@@ -816,7 +922,7 @@ void of_free_opp_table(struct device *dev)
 	/* Free static OPPs */
 	list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
 		if (!opp->dynamic)
-			__dev_pm_opp_remove(dev_opp, opp);
+			_opp_remove(dev_opp, opp);
 	}
 
 	mutex_unlock(&dev_opp_list_lock);

drivers/base/power/qos.c

@@ -64,6 +64,8 @@ enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
 	struct pm_qos_flags *pqf;
 	s32 val;
 
+	lockdep_assert_held(&dev->power.lock);
+
 	if (IS_ERR_OR_NULL(qos))
 		return PM_QOS_FLAGS_UNDEFINED;
 
@@ -104,6 +106,8 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
  */
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
+	lockdep_assert_held(&dev->power.lock);
+
 	return IS_ERR_OR_NULL(dev->power.qos) ?
 		0 : pm_qos_read_value(&dev->power.qos->resume_latency);
 }

drivers/devfreq/Kconfig

@@ -87,4 +87,16 @@ config ARM_EXYNOS5_BUS_DEVFREQ
 	  It reads PPMU counters of memory controllers and adjusts the
 	  operating frequencies and voltages with OPP support.
 
+config ARM_TEGRA_DEVFREQ
+       tristate "Tegra DEVFREQ Driver"
+       depends on ARCH_TEGRA_124_SOC
+       select DEVFREQ_GOV_SIMPLE_ONDEMAND
+       select PM_OPP
+       help
+         This adds the DEVFREQ driver for the Tegra family of SoCs.
+         It reads ACTMON counters of memory controllers and adjusts the
+         operating frequencies and voltages with OPP support.
+
+source "drivers/devfreq/event/Kconfig"
+
 endif # PM_DEVFREQ

drivers/devfreq/Makefile

 obj-$(CONFIG_PM_DEVFREQ)	+= devfreq.o
+obj-$(CONFIG_PM_DEVFREQ_EVENT)	+= devfreq-event.o
 obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)	+= governor_simpleondemand.o
 obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
@@ -7,3 +8,7 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
 obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
+obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o
+
+# DEVFREQ Event Drivers
+obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/

drivers/devfreq/devfreq-event.c

+/*
+ * devfreq-event: a framework to provide raw data and events of devfreq devices
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This driver is based on drivers/devfreq/devfreq.c.
+ */
+
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/of.h>
+
+static struct class *devfreq_event_class;
+
+/* The list of all devfreq event list */
+static LIST_HEAD(devfreq_event_list);
+static DEFINE_MUTEX(devfreq_event_list_lock);
+
+#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
+
+/**
+ * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
+ *				 the enable_count of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function increase the enable_count and enable the
+ * devfreq-event device. The devfreq-event device should be enabled before
+ * using it by devfreq device.
+ */
+int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->enable
+			&& edev->enable_count == 0) {
+		ret = edev->desc->ops->enable(edev);
+		if (ret < 0)
+			goto err;
+	}
+	edev->enable_count++;
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
+
+/**
+ * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
+ *				  the enable_count of the devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function decrease the enable_count and disable the
+ * devfreq-event device. After the devfreq-event device is disabled,
+ * devfreq device can't use the devfreq-event device for get/set/reset
+ * operations.
+ */
+int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->enable_count <= 0) {
+		dev_warn(&edev->dev, "unbalanced enable_count\n");
+		ret = -EIO;
+		goto err;
+	}
+
+	if (edev->desc->ops && edev->desc->ops->disable
+			&& edev->enable_count == 1) {
+		ret = edev->desc->ops->disable(edev);
+		if (ret < 0)
+			goto err;
+	}
+	edev->enable_count--;
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
+
+/**
+ * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
+ *				not.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function check whether devfreq-event dev is enabled or not.
+ * If return true, the devfreq-event dev is enabeld. If return false, the
+ * devfreq-event dev is disabled.
+ */
+bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
+{
+	bool enabled = false;
+
+	if (!edev || !edev->desc)
+		return enabled;
+
+	mutex_lock(&edev->lock);
+
+	if (edev->enable_count > 0)
+		enabled = true;
+
+	mutex_unlock(&edev->lock);
+
+	return enabled;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
+
+/**
+ * devfreq_event_set_event() - Set event to devfreq-event dev to start.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function set the event to the devfreq-event device to start
+ * for getting the event data which could be various event type.
+ */
+int devfreq_event_set_event(struct devfreq_event_dev *edev)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->set_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->set_event(edev);
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_set_event);
+
+/**
+ * devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
+ * @edev	: the devfreq-event device
+ * @edata	: the calculated data of devfreq-event device
+ *
+ * Note that this function get the calculated event data from devfreq-event dev
+ * after stoping the progress of whole sequence of devfreq-event dev.
+ */
+int devfreq_event_get_event(struct devfreq_event_dev *edev,
+			    struct devfreq_event_data *edata)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->get_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EINVAL;
+
+	edata->total_count = edata->load_count = 0;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->get_event(edev, edata);
+	if (ret < 0)
+		edata->total_count = edata->load_count = 0;
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_event);
+
+/**
+ * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function stop all operations of devfreq-event dev and reset
+ * the current event data to make the devfreq-event device into initial state.
+ */
+int devfreq_event_reset_event(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->reset)
+		ret = edev->desc->ops->reset(edev);
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
+
+/**
+ * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
+ *					 devicetree.
+ * @dev		: the pointer to the given device
+ * @index	: the index into list of devfreq-event device
+ *
+ * Note that this function return the pointer of devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
+						      int index)
+{
+	struct device_node *node;
+	struct devfreq_event_dev *edev;
+
+	if (!dev->of_node) {
+		dev_err(dev, "device does not have a device node entry\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	node = of_parse_phandle(dev->of_node, "devfreq-events", index);
+	if (!node) {
+		dev_err(dev, "failed to get phandle in %s node\n",
+			dev->of_node->full_name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_for_each_entry(edev, &devfreq_event_list, node) {
+		if (!strcmp(edev->desc->name, node->name))
+			goto out;
+	}
+	edev = NULL;
+out:
+	mutex_unlock(&devfreq_event_list_lock);
+
+	if (!edev) {
+		dev_err(dev, "unable to get devfreq-event device : %s\n",
+			node->name);
+		of_node_put(node);
+		return ERR_PTR(-ENODEV);
+	}
+
+	of_node_put(node);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
+
+/**
+ * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
+ * @dev		: the pointer to the given device
+ *
+ * Note that this function return the count of devfreq-event devices.
+ */
+int devfreq_event_get_edev_count(struct device *dev)
+{
+	int count;
+
+	if (!dev->of_node) {
+		dev_err(dev, "device does not have a device node entry\n");
+		return -EINVAL;
+	}
+
+	count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
+						sizeof(u32));
+	if (count < 0 ) {
+		dev_err(dev,
+			"failed to get the count of devfreq-event in %s node\n",
+			dev->of_node->full_name);
+		return count;
+	}
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
+
+static void devfreq_event_release_edev(struct device *dev)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	kfree(edev);
+}
+
+/**
+ * devfreq_event_add_edev() - Add new devfreq-event device.
+ * @dev		: the device owning the devfreq-event device being created
+ * @desc	: the devfreq-event device's decriptor which include essential
+ *		  data for devfreq-event device.
+ *
+ * Note that this function add new devfreq-event device to devfreq-event class
+ * list and register the device of the devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+						struct devfreq_event_desc *desc)
+{
+	struct devfreq_event_dev *edev;
+	static atomic_t event_no = ATOMIC_INIT(0);
+	int ret;
+
+	if (!dev || !desc)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->name || !desc->ops)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->ops->set_event || !desc->ops->get_event)
+		return ERR_PTR(-EINVAL);
+
+	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
+	if (!edev)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&edev->lock);
+	edev->desc = desc;
+	edev->enable_count = 0;
+	edev->dev.parent = dev;
+	edev->dev.class = devfreq_event_class;
+	edev->dev.release = devfreq_event_release_edev;
+
+	dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
+	ret = device_register(&edev->dev);
+	if (ret < 0) {
+		put_device(&edev->dev);
+		return ERR_PTR(ret);
+	}
+	dev_set_drvdata(&edev->dev, edev);
+
+	INIT_LIST_HEAD(&edev->node);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_add(&edev->node, &devfreq_event_list);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
+
+/**
+ * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
+ * @dev		: the devfreq-event device
+ *
+ * Note that this function remove the registered devfreq-event device.
+ */
+int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
+{
+	if (!edev)
+		return -EINVAL;
+
+	WARN_ON(edev->enable_count);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_del(&edev->node);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	device_unregister(&edev->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
+
+static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
+{
+	struct devfreq_event_dev **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+static void devm_devfreq_event_release(struct device *dev, void *res)
+{
+	devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
+}
+
+/**
+ * devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
+ * @dev		: the device owning the devfreq-event device being created
+ * @desc	: the devfreq-event device's decriptor which include essential
+ *		  data for devfreq-event device.
+ *
+ * Note that this function manages automatically the memory of devfreq-event
+ * device using device resource management and simplify the free operation
+ * for memory of devfreq-event device.
+ */
+struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
+						struct devfreq_event_desc *desc)
+{
+	struct devfreq_event_dev **ptr, *edev;
+
+	ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	edev = devfreq_event_add_edev(dev, desc);
+	if (IS_ERR(edev)) {
+		devres_free(ptr);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	*ptr = edev;
+	devres_add(dev, ptr);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
+
+/**
+ * devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
+ * @dev		: the device owning the devfreq-event device being created
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function manages automatically the memory of devfreq-event
+ * device using device resource management.
+ */
+void devm_devfreq_event_remove_edev(struct device *dev,
+				struct devfreq_event_dev *edev)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_event_release,
+			       devm_devfreq_event_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
+
+/*
+ * Device attributes for devfreq-event class.
+ */
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", edev->desc->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t enable_count_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n", edev->enable_count);
+}
+static DEVICE_ATTR_RO(enable_count);
+
+static struct attribute *devfreq_event_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_enable_count.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(devfreq_event);
+
+static int __init devfreq_event_init(void)
+{
+	devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
+	if (IS_ERR(devfreq_event_class)) {
+		pr_err("%s: couldn't create class\n", __FILE__);
+		return PTR_ERR(devfreq_event_class);
+	}
+
+	devfreq_event_class->dev_groups = devfreq_event_groups;
+
+	return 0;
+}
+subsys_initcall(devfreq_event_init);
+
+static void __exit devfreq_event_exit(void)
+{
+	class_destroy(devfreq_event_class);
+}
+module_exit(devfreq_event_exit);
+
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_DESCRIPTION("DEVFREQ-Event class support");
+MODULE_LICENSE("GPL");

drivers/devfreq/event/Kconfig

+menuconfig PM_DEVFREQ_EVENT
+	bool "DEVFREQ-Event device Support"
+	help
+	  The devfreq-event device provide the raw data and events which
+	  indicate the current state of devfreq-event device. The provided
+	  data from devfreq-event device is used to monitor the state of
+	  device and determine the suitable size of resource to reduce the
+	  wasted resource.
+
+	  The devfreq-event device can support the various type of events
+	  (e.g., raw data, utilization, latency, bandwidth). The events
+	  may be used by devfreq governor and other subsystem.
+
+if PM_DEVFREQ_EVENT
+
+config DEVFREQ_EVENT_EXYNOS_PPMU
+	bool "EXYNOS PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
+	depends on ARCH_EXYNOS
+	select PM_OPP
+	help
+	  This add the devfreq-event driver for Exynos SoC. It provides PPMU
+	  (Platform Performance Monitoring Unit) counters to estimate the
+	  utilization of each module.
+
+endif # PM_DEVFREQ_EVENT

drivers/devfreq/event/Makefile

+# Exynos DEVFREQ Event Drivers
+obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_PPMU) += exynos-ppmu.o

drivers/devfreq/event/exynos-ppmu.c

+/*
+ * exynos_ppmu.c - EXYNOS PPMU (Platform Performance Monitoring Unit) support
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This driver is based on drivers/devfreq/exynos/exynos_ppmu.c
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/suspend.h>
+#include <linux/devfreq-event.h>
+
+#include "exynos-ppmu.h"
+
+struct exynos_ppmu_data {
+	void __iomem *base;
+	struct clk *clk;
+};
+
+struct exynos_ppmu {
+	struct devfreq_event_dev **edev;
+	struct devfreq_event_desc *desc;
+	unsigned int num_events;
+
+	struct device *dev;
+	struct mutex lock;
+
+	struct exynos_ppmu_data ppmu;
+};
+
+#define PPMU_EVENT(name)			\
+	{ "ppmu-event0-"#name, PPMU_PMNCNT0 },	\
+	{ "ppmu-event1-"#name, PPMU_PMNCNT1 },	\
+	{ "ppmu-event2-"#name, PPMU_PMNCNT2 },	\
+	{ "ppmu-event3-"#name, PPMU_PMNCNT3 }
+
+struct __exynos_ppmu_events {
+	char *name;
+	int id;
+} ppmu_events[] = {
+	/* For Exynos3250, Exynos4 and Exynos5260 */
+	PPMU_EVENT(g3d),
+	PPMU_EVENT(fsys),
+
+	/* For Exynos4 SoCs and Exynos3250 */
+	PPMU_EVENT(dmc0),
+	PPMU_EVENT(dmc1),
+	PPMU_EVENT(cpu),
+	PPMU_EVENT(rightbus),
+	PPMU_EVENT(leftbus),
+	PPMU_EVENT(lcd0),
+	PPMU_EVENT(camif),
+
+	/* Only for Exynos3250 and Exynos5260 */
+	PPMU_EVENT(mfc),
+
+	/* Only for Exynos4 SoCs */
+	PPMU_EVENT(mfc-left),
+	PPMU_EVENT(mfc-right),
+
+	/* Only for Exynos5260 SoCs */
+	PPMU_EVENT(drex0-s0),
+	PPMU_EVENT(drex0-s1),
+	PPMU_EVENT(drex1-s0),
+	PPMU_EVENT(drex1-s1),
+	PPMU_EVENT(eagle),
+	PPMU_EVENT(kfc),
+	PPMU_EVENT(isp),
+	PPMU_EVENT(fimc),
+	PPMU_EVENT(gscl),
+	PPMU_EVENT(mscl),
+	PPMU_EVENT(fimd0x),
+	PPMU_EVENT(fimd1x),
+	{ /* sentinel */ },
+};
+
+static int exynos_ppmu_find_ppmu_id(struct devfreq_event_dev *edev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ppmu_events); i++)
+		if (!strcmp(edev->desc->name, ppmu_events[i].name))
+			return ppmu_events[i].id;
+
+	return -EINVAL;
+}
+
+static int exynos_ppmu_disable(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	u32 pmnc;
+
+	/* Disable all counters */
+	__raw_writel(PPMU_CCNT_MASK |
+		     PPMU_PMCNT0_MASK |
+		     PPMU_PMCNT1_MASK |
+		     PPMU_PMCNT2_MASK |
+		     PPMU_PMCNT3_MASK,
+		     info->ppmu.base + PPMU_CNTENC);
+
+	/* Disable PPMU */
+	pmnc = __raw_readl(info->ppmu.base + PPMU_PMNC);
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	__raw_writel(pmnc, info->ppmu.base + PPMU_PMNC);
+
+	return 0;
+}
+
+static int exynos_ppmu_set_event(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	u32 pmnc, cntens;
+
+	if (id < 0)
+		return id;
+
+	/* Enable specific counter */
+	cntens = __raw_readl(info->ppmu.base + PPMU_CNTENS);
+	cntens |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	__raw_writel(cntens, info->ppmu.base + PPMU_CNTENS);
+
+	/* Set the event of Read/Write data count  */
+	__raw_writel(PPMU_RO_DATA_CNT | PPMU_WO_DATA_CNT,
+			info->ppmu.base + PPMU_BEVTxSEL(id));
+
+	/* Reset cycle counter/performance counter and enable PPMU */
+	pmnc = __raw_readl(info->ppmu.base + PPMU_PMNC);
+	pmnc &= ~(PPMU_PMNC_ENABLE_MASK
+			| PPMU_PMNC_COUNTER_RESET_MASK
+			| PPMU_PMNC_CC_RESET_MASK);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_ENABLE_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_COUNTER_RESET_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_CC_RESET_SHIFT);
+	__raw_writel(pmnc, info->ppmu.base + PPMU_PMNC);
+
+	return 0;
+}
+
+static int exynos_ppmu_get_event(struct devfreq_event_dev *edev,
+				struct devfreq_event_data *edata)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	u32 pmnc, cntenc;
+
+	if (id < 0)
+		return -EINVAL;
+
+	/* Disable PPMU */
+	pmnc = __raw_readl(info->ppmu.base + PPMU_PMNC);
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	__raw_writel(pmnc, info->ppmu.base + PPMU_PMNC);
+
+	/* Read cycle count */
+	edata->total_count = __raw_readl(info->ppmu.base + PPMU_CCNT);
+
+	/* Read performance count */
+	switch (id) {
+	case PPMU_PMNCNT0:
+	case PPMU_PMNCNT1:
+	case PPMU_PMNCNT2:
+		edata->load_count
+			= __raw_readl(info->ppmu.base + PPMU_PMNCT(id));
+		break;
+	case PPMU_PMNCNT3:
+		edata->load_count =
+			((__raw_readl(info->ppmu.base + PPMU_PMCNT3_HIGH) << 8)
+			| __raw_readl(info->ppmu.base + PPMU_PMCNT3_LOW));
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Disable specific counter */
+	cntenc = __raw_readl(info->ppmu.base + PPMU_CNTENC);
+	cntenc |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	__raw_writel(cntenc, info->ppmu.base + PPMU_CNTENC);
+
+	dev_dbg(&edev->dev, "%s (event: %ld/%ld)\n", edev->desc->name,
+					edata->load_count, edata->total_count);
+
+	return 0;
+}
+
+static struct devfreq_event_ops exynos_ppmu_ops = {
+	.disable = exynos_ppmu_disable,
+	.set_event = exynos_ppmu_set_event,
+	.get_event = exynos_ppmu_get_event,
+};
+
+static int of_get_devfreq_events(struct device_node *np,
+				 struct exynos_ppmu *info)
+{
+	struct devfreq_event_desc *desc;
+	struct device *dev = info->dev;
+	struct device_node *events_np, *node;
+	int i, j, count;
+
+	events_np = of_get_child_by_name(np, "events");
+	if (!events_np) {
+		dev_err(dev,
+			"failed to get child node of devfreq-event devices\n");
+		return -EINVAL;
+	}
+
+	count = of_get_child_count(events_np);
+	desc = devm_kzalloc(dev, sizeof(*desc) * count, GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+	info->num_events = count;
+
+	j = 0;
+	for_each_child_of_node(events_np, node) {
+		for (i = 0; i < ARRAY_SIZE(ppmu_events); i++) {
+			if (!ppmu_events[i].name)
+				continue;
+
+			if (!of_node_cmp(node->name, ppmu_events[i].name))
+				break;
+		}
+
+		if (i == ARRAY_SIZE(ppmu_events)) {
+			dev_warn(dev,
+				"don't know how to configure events : %s\n",
+				node->name);
+			continue;
+		}
+
+		desc[j].ops = &exynos_ppmu_ops;
+		desc[j].driver_data = info;
+
+		of_property_read_string(node, "event-name", &desc[j].name);
+
+		j++;
+
+		of_node_put(node);
+	}
+	info->desc = desc;
+
+	of_node_put(events_np);
+
+	return 0;
+}
+
+static int exynos_ppmu_parse_dt(struct exynos_ppmu *info)
+{
+	struct device *dev = info->dev;
+	struct device_node *np = dev->of_node;
+	int ret = 0;
+
+	if (!np) {
+		dev_err(dev, "failed to find devicetree node\n");
+		return -EINVAL;
+	}
+
+	/* Maps the memory mapped IO to control PPMU register */
+	info->ppmu.base = of_iomap(np, 0);
+	if (IS_ERR_OR_NULL(info->ppmu.base)) {
+		dev_err(dev, "failed to map memory region\n");
+		return -ENOMEM;
+	}
+
+	info->ppmu.clk = devm_clk_get(dev, "ppmu");
+	if (IS_ERR(info->ppmu.clk)) {
+		info->ppmu.clk = NULL;
+		dev_warn(dev, "cannot get PPMU clock\n");
+	}
+
+	ret = of_get_devfreq_events(np, info);
+	if (ret < 0) {
+		dev_err(dev, "failed to parse exynos ppmu dt node\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	iounmap(info->ppmu.base);
+
+	return ret;
+}
+
+static int exynos_ppmu_probe(struct platform_device *pdev)
+{
+	struct exynos_ppmu *info;
+	struct devfreq_event_dev **edev;
+	struct devfreq_event_desc *desc;
+	int i, ret = 0, size;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	mutex_init(&info->lock);
+	info->dev = &pdev->dev;
+
+	/* Parse dt data to get resource */
+	ret = exynos_ppmu_parse_dt(info);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"failed to parse devicetree for resource\n");
+		return ret;
+	}
+	desc = info->desc;
+
+	size = sizeof(struct devfreq_event_dev *) * info->num_events;
+	info->edev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+	if (!info->edev) {
+		dev_err(&pdev->dev,
+			"failed to allocate memory devfreq-event devices\n");
+		return -ENOMEM;
+	}
+	edev = info->edev;
+	platform_set_drvdata(pdev, info);
+
+	for (i = 0; i < info->num_events; i++) {
+		edev[i] = devm_devfreq_event_add_edev(&pdev->dev, &desc[i]);
+		if (IS_ERR(edev)) {
+			ret = PTR_ERR(edev);
+			dev_err(&pdev->dev,
+				"failed to add devfreq-event device\n");
+			goto err;
+		}
+	}
+
+	clk_prepare_enable(info->ppmu.clk);
+
+	return 0;
+err:
+	iounmap(info->ppmu.base);
+
+	return ret;
+}
+
+static int exynos_ppmu_remove(struct platform_device *pdev)
+{
+	struct exynos_ppmu *info = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(info->ppmu.clk);
+	iounmap(info->ppmu.base);
+
+	return 0;
+}
+
+static struct of_device_id exynos_ppmu_id_match[] = {
+	{ .compatible = "samsung,exynos-ppmu", },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver exynos_ppmu_driver = {
+	.probe	= exynos_ppmu_probe,
+	.remove	= exynos_ppmu_remove,
+	.driver = {
+		.name	= "exynos-ppmu",
+		.of_match_table = exynos_ppmu_id_match,
+	},
+};
+module_platform_driver(exynos_ppmu_driver);
+
+MODULE_DESCRIPTION("Exynos PPMU(Platform Performance Monitoring Unit) driver");
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_LICENSE("GPL");

drivers/devfreq/event/exynos-ppmu.h

+/*
+ * exynos_ppmu.h - EXYNOS PPMU header file
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __EXYNOS_PPMU_H__
+#define __EXYNOS_PPMU_H__
+
+enum ppmu_state {
+	PPMU_DISABLE = 0,
+	PPMU_ENABLE,
+};
+
+enum ppmu_counter {
+	PPMU_PMNCNT0 = 0,
+	PPMU_PMNCNT1,
+	PPMU_PMNCNT2,
+	PPMU_PMNCNT3,
+
+	PPMU_PMNCNT_MAX,
+};
+
+enum ppmu_event_type {
+	PPMU_RO_BUSY_CYCLE_CNT	= 0x0,
+	PPMU_WO_BUSY_CYCLE_CNT	= 0x1,
+	PPMU_RW_BUSY_CYCLE_CNT	= 0x2,
+	PPMU_RO_REQUEST_CNT	= 0x3,
+	PPMU_WO_REQUEST_CNT	= 0x4,
+	PPMU_RO_DATA_CNT	= 0x5,
+	PPMU_WO_DATA_CNT	= 0x6,
+	PPMU_RO_LATENCY		= 0x12,
+	PPMU_WO_LATENCY		= 0x16,
+};
+
+enum ppmu_reg {
+	/* PPC control register */
+	PPMU_PMNC		= 0x00,
+	PPMU_CNTENS		= 0x10,
+	PPMU_CNTENC		= 0x20,
+	PPMU_INTENS		= 0x30,
+	PPMU_INTENC		= 0x40,
+	PPMU_FLAG		= 0x50,
+
+	/* Cycle Counter and Performance Event Counter Register */
+	PPMU_CCNT		= 0x100,
+	PPMU_PMCNT0		= 0x110,
+	PPMU_PMCNT1		= 0x120,
+	PPMU_PMCNT2		= 0x130,
+	PPMU_PMCNT3_HIGH	= 0x140,
+	PPMU_PMCNT3_LOW		= 0x150,
+
+	/* Bus Event Generator */
+	PPMU_BEVT0SEL		= 0x1000,
+	PPMU_BEVT1SEL		= 0x1100,
+	PPMU_BEVT2SEL		= 0x1200,
+	PPMU_BEVT3SEL		= 0x1300,
+	PPMU_COUNTER_RESET	= 0x1810,
+	PPMU_READ_OVERFLOW_CNT	= 0x1810,
+	PPMU_READ_UNDERFLOW_CNT	= 0x1814,
+	PPMU_WRITE_OVERFLOW_CNT	= 0x1850,
+	PPMU_WRITE_UNDERFLOW_CNT = 0x1854,
+	PPMU_READ_PENDING_CNT	= 0x1880,
+	PPMU_WRITE_PENDING_CNT	= 0x1884
+};
+
+/* PMNC register */
+#define PPMU_PMNC_CC_RESET_SHIFT	2
+#define PPMU_PMNC_COUNTER_RESET_SHIFT	1
+#define PPMU_PMNC_ENABLE_SHIFT		0
+#define PPMU_PMNC_START_MODE_MASK	BIT(16)
+#define PPMU_PMNC_CC_DIVIDER_MASK	BIT(3)
+#define PPMU_PMNC_CC_RESET_MASK		BIT(2)
+#define PPMU_PMNC_COUNTER_RESET_MASK	BIT(1)
+#define PPMU_PMNC_ENABLE_MASK		BIT(0)
+
+/* CNTENS/CNTENC/INTENS/INTENC/FLAG register */
+#define PPMU_CCNT_MASK			BIT(31)
+#define PPMU_PMCNT3_MASK		BIT(3)
+#define PPMU_PMCNT2_MASK		BIT(2)
+#define PPMU_PMCNT1_MASK		BIT(1)
+#define PPMU_PMCNT0_MASK		BIT(0)
+
+/* PPMU_PMNCTx/PPMU_BETxSEL registers */
+#define PPMU_PMNCT(x)			(PPMU_PMCNT0 + (0x10 * x))
+#define PPMU_BEVTxSEL(x)		(PPMU_BEVT0SEL + (0x100 * x))
+
+#endif /* __EXYNOS_PPMU_H__ */

drivers/devfreq/tegra-devfreq.c

+/*
+ * A devfreq driver for NVIDIA Tegra SoCs
+ *
+ * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
+ * Copyright (C) 2014 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/devfreq.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/reset.h>
+
+#include "governor.h"
+
+#define ACTMON_GLB_STATUS					0x0
+#define ACTMON_GLB_PERIOD_CTRL					0x4
+
+#define ACTMON_DEV_CTRL						0x0
+#define ACTMON_DEV_CTRL_K_VAL_SHIFT				10
+#define ACTMON_DEV_CTRL_ENB_PERIODIC				BIT(18)
+#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN			BIT(20)
+#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN			BIT(21)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT	23
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT	26
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN		BIT(29)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN		BIT(30)
+#define ACTMON_DEV_CTRL_ENB					BIT(31)
+
+#define ACTMON_DEV_UPPER_WMARK					0x4
+#define ACTMON_DEV_LOWER_WMARK					0x8
+#define ACTMON_DEV_INIT_AVG					0xc
+#define ACTMON_DEV_AVG_UPPER_WMARK				0x10
+#define ACTMON_DEV_AVG_LOWER_WMARK				0x14
+#define ACTMON_DEV_COUNT_WEIGHT					0x18
+#define ACTMON_DEV_AVG_COUNT					0x20
+#define ACTMON_DEV_INTR_STATUS					0x24
+
+#define ACTMON_INTR_STATUS_CLEAR				0xffffffff
+
+#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER			BIT(31)
+#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER			BIT(30)
+
+#define ACTMON_ABOVE_WMARK_WINDOW				1
+#define ACTMON_BELOW_WMARK_WINDOW				3
+#define ACTMON_BOOST_FREQ_STEP					16000
+
+/* activity counter is incremented every 256 memory transactions, and each
+ * transaction takes 4 EMC clocks for Tegra124; So the COUNT_WEIGHT is
+ * 4 * 256 = 1024.
+ */
+#define ACTMON_COUNT_WEIGHT					0x400
+
+/*
+ * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
+ * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
+ */
+#define ACTMON_AVERAGE_WINDOW_LOG2			6
+#define ACTMON_SAMPLING_PERIOD				12 /* ms */
+#define ACTMON_DEFAULT_AVG_BAND				6  /* 1/10 of % */
+
+#define KHZ							1000
+
+/* Assume that the bus is saturated if the utilization is 25% */
+#define BUS_SATURATION_RATIO					25
+
+/**
+ * struct tegra_devfreq_device_config - configuration specific to an ACTMON
+ * device
+ *
+ * Coefficients and thresholds are in %
+ */
+struct tegra_devfreq_device_config {
+	u32		offset;
+	u32		irq_mask;
+
+	unsigned int	boost_up_coeff;
+	unsigned int	boost_down_coeff;
+	unsigned int	boost_up_threshold;
+	unsigned int	boost_down_threshold;
+	u32		avg_dependency_threshold;
+};
+
+enum tegra_actmon_device {
+	MCALL = 0,
+	MCCPU,
+};
+
+static struct tegra_devfreq_device_config actmon_device_configs[] = {
+	{
+		/* MCALL */
+		.offset = 0x1c0,
+		.irq_mask = 1 << 26,
+		.boost_up_coeff = 200,
+		.boost_down_coeff = 50,
+		.boost_up_threshold = 60,
+		.boost_down_threshold = 40,
+	},
+	{
+		/* MCCPU */
+		.offset = 0x200,
+		.irq_mask = 1 << 25,
+		.boost_up_coeff = 800,
+		.boost_down_coeff = 90,
+		.boost_up_threshold = 27,
+		.boost_down_threshold = 10,
+		.avg_dependency_threshold = 50000,
+	},
+};
+
+/**
+ * struct tegra_devfreq_device - state specific to an ACTMON device
+ *
+ * Frequencies are in kHz.
+ */
+struct tegra_devfreq_device {
+	const struct tegra_devfreq_device_config *config;
+
+	void __iomem	*regs;
+	u32		avg_band_freq;
+	u32		avg_count;
+
+	unsigned long	target_freq;
+	unsigned long	boost_freq;
+};
+
+struct tegra_devfreq {
+	struct devfreq		*devfreq;
+
+	struct platform_device	*pdev;
+	struct reset_control	*reset;
+	struct clk		*clock;
+	void __iomem		*regs;
+
+	spinlock_t		lock;
+
+	struct clk		*emc_clock;
+	unsigned long		max_freq;
+	unsigned long		cur_freq;
+	struct notifier_block	rate_change_nb;
+
+	struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
+};
+
+struct tegra_actmon_emc_ratio {
+	unsigned long cpu_freq;
+	unsigned long emc_freq;
+};
+
+static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
+	{ 1400000, ULONG_MAX },
+	{ 1200000,    750000 },
+	{ 1100000,    600000 },
+	{ 1000000,    500000 },
+	{  800000,    375000 },
+	{  500000,    200000 },
+	{  250000,    100000 },
+};
+
+static unsigned long do_percent(unsigned long val, unsigned int pct)
+{
+	return val * pct / 100;
+}
+
+static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq_device *dev)
+{
+	u32 avg = dev->avg_count;
+	u32 band = dev->avg_band_freq * ACTMON_SAMPLING_PERIOD;
+
+	writel(avg + band, dev->regs + ACTMON_DEV_AVG_UPPER_WMARK);
+	avg = max(avg, band);
+	writel(avg - band, dev->regs + ACTMON_DEV_AVG_LOWER_WMARK);
+}
+
+static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
+				       struct tegra_devfreq_device *dev)
+{
+	u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
+
+	writel(do_percent(val, dev->config->boost_up_threshold),
+	       dev->regs + ACTMON_DEV_UPPER_WMARK);
+
+	writel(do_percent(val, dev->config->boost_down_threshold),
+	       dev->regs + ACTMON_DEV_LOWER_WMARK);
+}
+
+static void actmon_write_barrier(struct tegra_devfreq *tegra)
+{
+	/* ensure the update has reached the ACTMON */
+	wmb();
+	readl(tegra->regs + ACTMON_GLB_STATUS);
+}
+
+static irqreturn_t actmon_isr(int irq, void *data)
+{
+	struct tegra_devfreq *tegra = data;
+	struct tegra_devfreq_device *dev = NULL;
+	unsigned long flags;
+	u32 val;
+	unsigned int i;
+
+	val = readl(tegra->regs + ACTMON_GLB_STATUS);
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		if (val & tegra->devices[i].config->irq_mask) {
+			dev = tegra->devices + i;
+			break;
+		}
+	}
+
+	if (!dev)
+		return IRQ_NONE;
+
+	spin_lock_irqsave(&tegra->lock, flags);
+
+	dev->avg_count = readl(dev->regs + ACTMON_DEV_AVG_COUNT);
+	tegra_devfreq_update_avg_wmark(dev);
+
+	val = readl(dev->regs + ACTMON_DEV_INTR_STATUS);
+	if (val & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
+		val = readl(dev->regs + ACTMON_DEV_CTRL) |
+			ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
+			ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+
+		/*
+		 * new_boost = min(old_boost * up_coef + step, max_freq)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_up_coeff);
+		dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
+		if (dev->boost_freq >= tegra->max_freq) {
+			dev->boost_freq = tegra->max_freq;
+			val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+		}
+		writel(val, dev->regs + ACTMON_DEV_CTRL);
+	} else if (val & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
+		val = readl(dev->regs + ACTMON_DEV_CTRL) |
+			ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
+			ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+
+		/*
+		 * new_boost = old_boost * down_coef
+		 * or 0 if (old_boost * down_coef < step / 2)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_down_coeff);
+		if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
+			dev->boost_freq = 0;
+			val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+		}
+		writel(val, dev->regs + ACTMON_DEV_CTRL);
+	}
+
+	if (dev->config->avg_dependency_threshold) {
+		val = readl(dev->regs + ACTMON_DEV_CTRL);
+		if (dev->avg_count >= dev->config->avg_dependency_threshold)
+			val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+		else if (dev->boost_freq == 0)
+			val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+		writel(val, dev->regs + ACTMON_DEV_CTRL);
+	}
+
+	writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
+
+	actmon_write_barrier(tegra);
+
+	spin_unlock_irqrestore(&tegra->lock, flags);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
+					    unsigned long cpu_freq)
+{
+	unsigned int i;
+	struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
+
+	for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
+		if (cpu_freq >= ratio->cpu_freq) {
+			if (ratio->emc_freq >= tegra->max_freq)
+				return tegra->max_freq;
+			else
+				return ratio->emc_freq;
+		}
+	}
+
+	return 0;
+}
+
+static void actmon_update_target(struct tegra_devfreq *tegra,
+				 struct tegra_devfreq_device *dev)
+{
+	unsigned long cpu_freq = 0;
+	unsigned long static_cpu_emc_freq = 0;
+	unsigned int avg_sustain_coef;
+	unsigned long flags;
+
+	if (dev->config->avg_dependency_threshold) {
+		cpu_freq = cpufreq_get(0);
+		static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
+	}
+
+	spin_lock_irqsave(&tegra->lock, flags);
+
+	dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
+	avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
+	dev->target_freq = do_percent(dev->target_freq, avg_sustain_coef);
+	dev->target_freq += dev->boost_freq;
+
+	if (dev->avg_count >= dev->config->avg_dependency_threshold)
+		dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
+
+	spin_unlock_irqrestore(&tegra->lock, flags);
+}
+
+static irqreturn_t actmon_thread_isr(int irq, void *data)
+{
+	struct tegra_devfreq *tegra = data;
+
+	mutex_lock(&tegra->devfreq->lock);
+	update_devfreq(tegra->devfreq);
+	mutex_unlock(&tegra->devfreq->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
+				       unsigned long action, void *ptr)
+{
+	struct clk_notifier_data *data = ptr;
+	struct tegra_devfreq *tegra = container_of(nb, struct tegra_devfreq,
+						   rate_change_nb);
+	unsigned int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tegra->lock, flags);
+
+	switch (action) {
+	case POST_RATE_CHANGE:
+		tegra->cur_freq = data->new_rate / KHZ;
+
+		for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
+			tegra_devfreq_update_wmark(tegra, tegra->devices + i);
+
+		actmon_write_barrier(tegra);
+		break;
+	case PRE_RATE_CHANGE:
+		/* fall through */
+	case ABORT_RATE_CHANGE:
+		break;
+	};
+
+	spin_unlock_irqrestore(&tegra->lock, flags);
+
+	return NOTIFY_OK;
+}
+
+static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
+					  struct tegra_devfreq_device *dev)
+{
+	u32 val;
+
+	dev->avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
+	dev->target_freq = tegra->cur_freq;
+
+	dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
+	writel(dev->avg_count, dev->regs + ACTMON_DEV_INIT_AVG);
+
+	tegra_devfreq_update_avg_wmark(dev);
+	tegra_devfreq_update_wmark(tegra, dev);
+
+	writel(ACTMON_COUNT_WEIGHT, dev->regs + ACTMON_DEV_COUNT_WEIGHT);
+	writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
+
+	val = 0;
+	val |= ACTMON_DEV_CTRL_ENB_PERIODIC |
+	       ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN |
+	       ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
+	val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
+		<< ACTMON_DEV_CTRL_K_VAL_SHIFT;
+	val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
+	val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
+	val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN |
+	       ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+
+	writel(val, dev->regs + ACTMON_DEV_CTRL);
+
+	actmon_write_barrier(tegra);
+
+	val = readl(dev->regs + ACTMON_DEV_CTRL);
+	val |= ACTMON_DEV_CTRL_ENB;
+	writel(val, dev->regs + ACTMON_DEV_CTRL);
+
+	actmon_write_barrier(tegra);
+}
+
+static int tegra_devfreq_suspend(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *actmon_dev;
+	unsigned int i;
+	u32 val;
+
+	pdev = container_of(dev, struct platform_device, dev);
+	tegra = platform_get_drvdata(pdev);
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		actmon_dev = &tegra->devices[i];
+
+		val = readl(actmon_dev->regs + ACTMON_DEV_CTRL);
+		val &= ~ACTMON_DEV_CTRL_ENB;
+		writel(val, actmon_dev->regs + ACTMON_DEV_CTRL);
+
+		writel(ACTMON_INTR_STATUS_CLEAR,
+		       actmon_dev->regs + ACTMON_DEV_INTR_STATUS);
+
+		actmon_write_barrier(tegra);
+	}
+
+	return 0;
+}
+
+static int tegra_devfreq_resume(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *actmon_dev;
+	unsigned int i;
+
+	pdev = container_of(dev, struct platform_device, dev);
+	tegra = platform_get_drvdata(pdev);
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		actmon_dev = &tegra->devices[i];
+
+		tegra_actmon_configure_device(tegra, actmon_dev);
+	}
+
+	return 0;
+}
+
+static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
+				u32 flags)
+{
+	struct platform_device *pdev;
+	struct tegra_devfreq *tegra;
+	struct dev_pm_opp *opp;
+	unsigned long rate = *freq * KHZ;
+
+	pdev = container_of(dev, struct platform_device, dev);
+	tegra = platform_get_drvdata(pdev);
+
+	rcu_read_lock();
+	opp = devfreq_recommended_opp(dev, &rate, flags);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
+		return PTR_ERR(opp);
+	}
+	rate = dev_pm_opp_get_freq(opp);
+	rcu_read_unlock();
+
+	/* TODO: Once we have per-user clk constraints, set a floor */
+	clk_set_rate(tegra->emc_clock, rate);
+
+	/* TODO: Set voltage as well */
+
+	return 0;
+}
+
+static int tegra_devfreq_get_dev_status(struct device *dev,
+					struct devfreq_dev_status *stat)
+{
+	struct platform_device *pdev;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *actmon_dev;
+
+	pdev = container_of(dev, struct platform_device, dev);
+	tegra = platform_get_drvdata(pdev);
+
+	stat->current_frequency = tegra->cur_freq;
+
+	/* To be used by the tegra governor */
+	stat->private_data = tegra;
+
+	/* The below are to be used by the other governors */
+
+	actmon_dev = &tegra->devices[MCALL];
+
+	/* Number of cycles spent on memory access */
+	stat->busy_time = actmon_dev->avg_count;
+
+	/* The bus can be considered to be saturated way before 100% */
+	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
+
+	/* Number of cycles in a sampling period */
+	stat->total_time = ACTMON_SAMPLING_PERIOD * tegra->cur_freq;
+
+	return 0;
+}
+
+static int tegra_devfreq_get_target(struct devfreq *devfreq,
+				    unsigned long *freq)
+{
+	struct devfreq_dev_status stat;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	unsigned long target_freq = 0;
+	unsigned int i;
+	int err;
+
+	err = devfreq->profile->get_dev_status(devfreq->dev.parent, &stat);
+	if (err)
+		return err;
+
+	tegra = stat.private_data;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = &tegra->devices[i];
+
+		actmon_update_target(tegra, dev);
+
+		target_freq = max(target_freq, dev->target_freq);
+	}
+
+	*freq = target_freq;
+
+	return 0;
+}
+
+static int tegra_devfreq_event_handler(struct devfreq *devfreq,
+				       unsigned int event, void *data)
+{
+	return 0;
+}
+
+static struct devfreq_governor tegra_devfreq_governor = {
+	.name = "tegra",
+	.get_target_freq = tegra_devfreq_get_target,
+	.event_handler = tegra_devfreq_event_handler,
+};
+
+static struct devfreq_dev_profile tegra_devfreq_profile = {
+	.polling_ms	= 0,
+	.target		= tegra_devfreq_target,
+	.get_dev_status	= tegra_devfreq_get_dev_status,
+};
+
+static int tegra_devfreq_probe(struct platform_device *pdev)
+{
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	struct resource *res;
+	unsigned long max_freq;
+	unsigned int i;
+	int irq;
+	int err;
+
+	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
+	if (!tegra)
+		return -ENOMEM;
+
+	spin_lock_init(&tegra->lock);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get regs resource\n");
+		return -ENODEV;
+	}
+
+	tegra->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(tegra->regs)) {
+		dev_err(&pdev->dev, "Failed to get IO memory\n");
+		return PTR_ERR(tegra->regs);
+	}
+
+	tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->reset)) {
+		dev_err(&pdev->dev, "Failed to get reset\n");
+		return PTR_ERR(tegra->reset);
+	}
+
+	tegra->clock = devm_clk_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->clock)) {
+		dev_err(&pdev->dev, "Failed to get actmon clock\n");
+		return PTR_ERR(tegra->clock);
+	}
+
+	tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
+	if (IS_ERR(tegra->emc_clock)) {
+		dev_err(&pdev->dev, "Failed to get emc clock\n");
+		return PTR_ERR(tegra->emc_clock);
+	}
+
+	err = of_init_opp_table(&pdev->dev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to init operating point table\n");
+		return err;
+	}
+
+	tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
+	err = clk_notifier_register(tegra->emc_clock, &tegra->rate_change_nb);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Failed to register rate change notifier\n");
+		return err;
+	}
+
+	reset_control_assert(tegra->reset);
+
+	err = clk_prepare_enable(tegra->clock);
+	if (err) {
+		reset_control_deassert(tegra->reset);
+		return err;
+	}
+
+	reset_control_deassert(tegra->reset);
+
+	max_freq = clk_round_rate(tegra->emc_clock, ULONG_MAX);
+	tegra->max_freq = max_freq / KHZ;
+
+	clk_set_rate(tegra->emc_clock, max_freq);
+
+	tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
+
+	writel(ACTMON_SAMPLING_PERIOD - 1,
+	       tegra->regs + ACTMON_GLB_PERIOD_CTRL);
+
+	for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
+		dev = tegra->devices + i;
+		dev->config = actmon_device_configs + i;
+		dev->regs = tegra->regs + dev->config->offset;
+
+		tegra_actmon_configure_device(tegra, tegra->devices + i);
+	}
+
+	err = devfreq_add_governor(&tegra_devfreq_governor);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add governor\n");
+		return err;
+	}
+
+	tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
+	tegra->devfreq = devm_devfreq_add_device(&pdev->dev,
+						 &tegra_devfreq_profile,
+						 "tegra",
+						 NULL);
+
+	irq = platform_get_irq(pdev, 0);
+	err = devm_request_threaded_irq(&pdev->dev, irq, actmon_isr,
+					actmon_thread_isr, IRQF_SHARED,
+					"tegra-devfreq", tegra);
+	if (err) {
+		dev_err(&pdev->dev, "Interrupt request failed\n");
+		return err;
+	}
+
+	platform_set_drvdata(pdev, tegra);
+
+	return 0;
+}
+
+static int tegra_devfreq_remove(struct platform_device *pdev)
+{
+	struct tegra_devfreq *tegra = platform_get_drvdata(pdev);
+
+	clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
+
+	clk_disable_unprepare(tegra->clock);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tegra_devfreq_pm_ops,
+			 tegra_devfreq_suspend,
+			 tegra_devfreq_resume);
+
+static struct of_device_id tegra_devfreq_of_match[] = {
+	{ .compatible = "nvidia,tegra124-actmon" },
+	{ },
+};
+
+static struct platform_driver tegra_devfreq_driver = {
+	.probe	= tegra_devfreq_probe,
+	.remove	= tegra_devfreq_remove,
+	.driver = {
+		.name		= "tegra-devfreq",
+		.owner		= THIS_MODULE,
+		.of_match_table = tegra_devfreq_of_match,
+		.pm		= &tegra_devfreq_pm_ops,
+	},
+};
+module_platform_driver(tegra_devfreq_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Tegra devfreq driver");
+MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");
+MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);

include/linux/devfreq-event.h

+/*
+ * devfreq-event: a framework to provide raw data and events of devfreq devices
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_DEVFREQ_EVENT_H__
+#define __LINUX_DEVFREQ_EVENT_H__
+
+#include <linux/device.h>
+
+/**
+ * struct devfreq_event_dev - the devfreq-event device
+ *
+ * @node	: Contain the devfreq-event device that have been registered.
+ * @dev		: the device registered by devfreq-event class. dev.parent is
+ *		  the device using devfreq-event.
+ * @lock	: a mutex to protect accessing devfreq-event.
+ * @enable_count: the number of enable function have been called.
+ * @desc	: the description for devfreq-event device.
+ *
+ * This structure contains devfreq-event device information.
+ */
+struct devfreq_event_dev {
+	struct list_head node;
+
+	struct device dev;
+	struct mutex lock;
+	u32 enable_count;
+
+	const struct devfreq_event_desc *desc;
+};
+
+/**
+ * struct devfreq_event_data - the devfreq-event data
+ *
+ * @load_count	: load count of devfreq-event device for the given period.
+ * @total_count	: total count of devfreq-event device for the given period.
+ *		  each count may represent a clock cycle, a time unit
+ *		  (ns/us/...), or anything the device driver wants.
+ *		  Generally, utilization is load_count / total_count.
+ *
+ * This structure contains the data of devfreq-event device for polling period.
+ */
+struct devfreq_event_data {
+	unsigned long load_count;
+	unsigned long total_count;
+};
+
+/**
+ * struct devfreq_event_ops - the operations of devfreq-event device
+ *
+ * @enable	: Enable the devfreq-event device.
+ * @disable	: Disable the devfreq-event device.
+ * @reset	: Reset all setting of the devfreq-event device.
+ * @set_event	: Set the specific event type for the devfreq-event device.
+ * @get_event	: Get the result of the devfreq-event devie with specific
+ *		  event type.
+ *
+ * This structure contains devfreq-event device operations which can be
+ * implemented by devfreq-event device drivers.
+ */
+struct devfreq_event_ops {
+	/* Optional functions */
+	int (*enable)(struct devfreq_event_dev *edev);
+	int (*disable)(struct devfreq_event_dev *edev);
+	int (*reset)(struct devfreq_event_dev *edev);
+
+	/* Mandatory functions */
+	int (*set_event)(struct devfreq_event_dev *edev);
+	int (*get_event)(struct devfreq_event_dev *edev,
+			 struct devfreq_event_data *edata);
+};
+
+/**
+ * struct devfreq_event_desc - the descriptor of devfreq-event device
+ *
+ * @name	: the name of devfreq-event device.
+ * @driver_data	: the private data for devfreq-event driver.
+ * @ops		: the operation to control devfreq-event device.
+ *
+ * Each devfreq-event device is described with a this structure.
+ * This structure contains the various data for devfreq-event device.
+ */
+struct devfreq_event_desc {
+	const char *name;
+	void *driver_data;
+
+	struct devfreq_event_ops *ops;
+};
+
+#if defined(CONFIG_PM_DEVFREQ_EVENT)
+extern int devfreq_event_enable_edev(struct devfreq_event_dev *edev);
+extern int devfreq_event_disable_edev(struct devfreq_event_dev *edev);
+extern bool devfreq_event_is_enabled(struct devfreq_event_dev *edev);
+extern int devfreq_event_set_event(struct devfreq_event_dev *edev);
+extern int devfreq_event_get_event(struct devfreq_event_dev *edev,
+				struct devfreq_event_data *edata);
+extern int devfreq_event_reset_event(struct devfreq_event_dev *edev);
+extern struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
+				struct device *dev, int index);
+extern int devfreq_event_get_edev_count(struct device *dev);
+extern struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+				struct devfreq_event_desc *desc);
+extern int devfreq_event_remove_edev(struct devfreq_event_dev *edev);
+extern struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
+				struct devfreq_event_desc *desc);
+extern void devm_devfreq_event_remove_edev(struct device *dev,
+				struct devfreq_event_dev *edev);
+static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
+{
+	return edev->desc->driver_data;
+}
+#else
+static inline int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
+{
+	return false;
+}
+
+static inline int devfreq_event_set_event(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_get_event(struct devfreq_event_dev *edev,
+					struct devfreq_event_data *edata)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_reset_event(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
+					struct device *dev, int index)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int devfreq_event_get_edev_count(struct device *dev)
+{
+	return -EINVAL;
+}
+
+static inline struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+					struct devfreq_event_desc *desc)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline struct devfreq_event_dev *devm_devfreq_event_add_edev(
+					struct device *dev,
+					struct devfreq_event_desc *desc)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline void devm_devfreq_event_remove_edev(struct device *dev,
+					struct devfreq_event_dev *edev)
+{
+}
+
+static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
+{
+	return NULL;
+}
+#endif /* CONFIG_PM_DEVFREQ_EVENT */
+
+#endif /* __LINUX_DEVFREQ_EVENT_H__ */

kernel/power/qos.c

@@ -41,6 +41,8 @@
 #include <linux/platform_device.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #include <linux/uaccess.h>
 #include <linux/export.h>
@@ -182,6 +184,81 @@ static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
 	c->target_value = value;
 }
 
+static inline int pm_qos_get_value(struct pm_qos_constraints *c);
+static int pm_qos_dbg_show_requests(struct seq_file *s, void *unused)
+{
+	struct pm_qos_object *qos = (struct pm_qos_object *)s->private;
+	struct pm_qos_constraints *c;
+	struct pm_qos_request *req;
+	char *type;
+	unsigned long flags;
+	int tot_reqs = 0;
+	int active_reqs = 0;
+
+	if (IS_ERR_OR_NULL(qos)) {
+		pr_err("%s: bad qos param!\n", __func__);
+		return -EINVAL;
+	}
+	c = qos->constraints;
+	if (IS_ERR_OR_NULL(c)) {
+		pr_err("%s: Bad constraints on qos?\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Lock to ensure we have a snapshot */
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	if (plist_head_empty(&c->list)) {
+		seq_puts(s, "Empty!\n");
+		goto out;
+	}
+
+	switch (c->type) {
+	case PM_QOS_MIN:
+		type = "Minimum";
+		break;
+	case PM_QOS_MAX:
+		type = "Maximum";
+		break;
+	case PM_QOS_SUM:
+		type = "Sum";
+		break;
+	default:
+		type = "Unknown";
+	}
+
+	plist_for_each_entry(req, &c->list, node) {
+		char *state = "Default";
+
+		if ((req->node).prio != c->default_value) {
+			active_reqs++;
+			state = "Active";
+		}
+		tot_reqs++;
+		seq_printf(s, "%d: %d: %s\n", tot_reqs,
+			   (req->node).prio, state);
+	}
+
+	seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n",
+		   type, pm_qos_get_value(c), active_reqs, tot_reqs);
+
+out:
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+	return 0;
+}
+
+static int pm_qos_dbg_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pm_qos_dbg_show_requests,
+			   inode->i_private);
+}
+
+static const struct file_operations pm_qos_debug_fops = {
+	.open           = pm_qos_dbg_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = single_release,
+};
+
 /**
  * pm_qos_update_target - manages the constraints list and calls the notifiers
  *  if needed
@@ -509,12 +586,17 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
 EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
 
 /* User space interface to PM QoS classes via misc devices */
-static int register_pm_qos_misc(struct pm_qos_object *qos)
+static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d)
 {
 	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
 	qos->pm_qos_power_miscdev.name = qos->name;
 	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
 
+	if (d) {
+		(void)debugfs_create_file(qos->name, S_IRUGO, d,
+					  (void *)qos, &pm_qos_debug_fops);
+	}
+
 	return misc_register(&qos->pm_qos_power_miscdev);
 }
 
@@ -608,11 +690,16 @@ static int __init pm_qos_power_init(void)
 {
 	int ret = 0;
 	int i;
+	struct dentry *d;
 
 	BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES);
 
+	d = debugfs_create_dir("pm_qos", NULL);
+	if (IS_ERR_OR_NULL(d))
+		d = NULL;
+
 	for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) {
-		ret = register_pm_qos_misc(pm_qos_array[i]);
+		ret = register_pm_qos_misc(pm_qos_array[i], d);
 		if (ret < 0) {
 			printk(KERN_ERR "pm_qos_param: %s setup failed\n",
 			       pm_qos_array[i]->name);