Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux

Pull thermal management update from Zhang Rui:
 "The most important one is to build thermal core and governor and cpu
  cooling code into one module.  This fixes a regression that thermal
  core does not work if it is built as module, since 3.7.  I'll backport
  them to stable kernel once those changes are in upstream.

  The largest batch is the thermal kernel-doc & coding style
  updates/cleanups from Eduardo.

  Highlights:

   - build all thermal framework code into one module to fix a
     regression that thermal does not work if it is built as module.

   - Marvell Armada 370/XP thermal sensor driver

   - thermal core/cpu cooling kernel-doc & coding style updates and
     cleanups.

   - Add Eduardo Valentin as thermal sub-maintainer, both in mailing
     list and patchwork.  He will help me on arm thermal drivers."

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (68 commits)
  thermal: db8500_cpufreq_cooling: remove usage of IS_ERR_OR_NULL()
  thermal: thermal_core: remove usage of IS_ERR_OR_NULL
  thermal: cpu_cooling: improve line breaking
  thermal: cpu_cooling: alignment improvements
  thermal: cpu_cooling: remove checkpatch.pl warning
  thermal: cpu_cooling: remove trailing blank line
  thermal: cpu_cooling: align on open parenthesis
  thermal: cpu_cooling: standardize comment style
  thermal: cpu_cooling: standardize end of function
  thermal: cpu_cooling: remove trailing white spaces
  Thermal: update documentation for thermal_zone_device_register
  thermal: update kernel-doc for thermal_zone_device_register
  thermal: update kernel-doc for create_trip_attrs
  thermal: update kernel-doc for thermal_cooling_device_register
  thermal: update kernel-doc for thermal_zone_unbind_cooling_device
  thermal: update kernel-doc for thermal_zone_bind_cooling_device
  thermal: use EXPORT_SYMBOL_GPL
  thermal: rename notify_thermal_framework to thermal_notify_framework
  thermal: update driver license
  thermal: use strlcpy instead of strcpy
  ...

1 files changed, 209 insertions, 86 deletions

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 8dc44cbb3e09..c94bf2e5de62 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -20,10 +20,8 @@
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
-#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/thermal.h>
-#include <linux/platform_device.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/slab.h>
@@ -31,21 +29,19 @@
 #include <linux/cpu_cooling.h>
 
 /**
- * struct cpufreq_cooling_device
+ * struct cpufreq_cooling_device - data for cooling device with cpufreq
  * @id: unique integer value corresponding to each cpufreq_cooling_device
  *	registered.
- * @cool_dev: thermal_cooling_device pointer to keep track of the the
- *	egistered cooling device.
+ * @cool_dev: thermal_cooling_device pointer to keep track of the
+ *	registered cooling device.
  * @cpufreq_state: integer value representing the current state of cpufreq
  *	cooling	devices.
  * @cpufreq_val: integer value representing the absolute value of the clipped
  *	frequency.
  * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
- * @node: list_head to link all cpufreq_cooling_device together.
  *
  * This structure is required for keeping information of each
- * cpufreq_cooling_device registered as a list whose head is represented by
- * cooling_cpufreq_list. In order to prevent corruption of this list a
+ * cpufreq_cooling_device registered. In order to prevent corruption of this a
  * mutex lock cooling_cpufreq_lock is used.
  */
 struct cpufreq_cooling_device {
@@ -54,9 +50,7 @@ struct cpufreq_cooling_device {
 	unsigned int cpufreq_state;
 	unsigned int cpufreq_val;
 	struct cpumask allowed_cpus;
-	struct list_head node;
 };
-static LIST_HEAD(cooling_cpufreq_list);
 static DEFINE_IDR(cpufreq_idr);
 static DEFINE_MUTEX(cooling_cpufreq_lock);
 
@@ -70,6 +64,11 @@ static struct cpufreq_cooling_device *notify_device;
  * get_idr - function to get a unique id.
  * @idr: struct idr * handle used to create a id.
  * @id: int * value generated by this function.
+ *
+ * This function will populate @id with an unique
+ * id, using the idr API.
+ *
+ * Return: 0 on success, an error code on failure.
  */
 static int get_idr(struct idr *idr, int *id)
 {
@@ -81,6 +80,7 @@ static int get_idr(struct idr *idr, int *id)
 	if (unlikely(ret < 0))
 		return ret;
 	*id = ret;
+
 	return 0;
 }
 
@@ -99,63 +99,162 @@ static void release_idr(struct idr *idr, int id)
 /* Below code defines functions to be used for cpufreq as cooling device */
 
 /**
- * is_cpufreq_valid - function to check if a cpu has frequency transition policy.
+ * is_cpufreq_valid - function to check frequency transitioning capability.
  * @cpu: cpu for which check is needed.
+ *
+ * This function will check the current state of the system if
+ * it is capable of changing the frequency for a given @cpu.
+ *
+ * Return: 0 if the system is not currently capable of changing
+ * the frequency of given cpu. !0 in case the frequency is changeable.
  */
 static int is_cpufreq_valid(int cpu)
 {
 	struct cpufreq_policy policy;
+
 	return !cpufreq_get_policy(&policy, cpu);
 }
 
+enum cpufreq_cooling_property {
+	GET_LEVEL,
+	GET_FREQ,
+	GET_MAXL,
+};
+
 /**
- * get_cpu_frequency - get the absolute value of frequency from level.
- * @cpu: cpu for which frequency is fetched.
- * @level: level of frequency, equals cooling state of cpu cooling device
- *	e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
+ * get_property - fetch a property of interest for a give cpu.
+ * @cpu: cpu for which the property is required
+ * @input: query parameter
+ * @output: query return
+ * @property: type of query (frequency, level, max level)
+ *
+ * This is the common function to
+ * 1. get maximum cpu cooling states
+ * 2. translate frequency to cooling state
+ * 3. translate cooling state to frequency
+ * Note that the code may be not in good shape
+ * but it is written in this way in order to:
+ * a) reduce duplicate code as most of the code can be shared.
+ * b) make sure the logic is consistent when translating between
+ *    cooling states and frequencies.
+ *
+ * Return: 0 on success, -EINVAL when invalid parameters are passed.
  */
-static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
+static int get_property(unsigned int cpu, unsigned long input,
+			unsigned int *output,
+			enum cpufreq_cooling_property property)
 {
-	int ret = 0, i = 0;
-	unsigned long level_index;
-	bool descend = false;
+	int i, j;
+	unsigned long max_level = 0, level = 0;
+	unsigned int freq = CPUFREQ_ENTRY_INVALID;
+	int descend = -1;
 	struct cpufreq_frequency_table *table =
 					cpufreq_frequency_get_table(cpu);
+
+	if (!output)
+		return -EINVAL;
+
 	if (!table)
-		return ret;
+		return -EINVAL;
 
-	while (table[i].frequency != CPUFREQ_TABLE_END) {
+	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+		/* ignore invalid entries */
 		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 			continue;
 
-		/*check if table in ascending or descending order*/
-		if ((table[i + 1].frequency != CPUFREQ_TABLE_END) &&
-			(table[i + 1].frequency < table[i].frequency)
-			&& !descend) {
-			descend = true;
-		}
+		/* ignore duplicate entry */
+		if (freq == table[i].frequency)
+			continue;
+
+		/* get the frequency order */
+		if (freq != CPUFREQ_ENTRY_INVALID && descend != -1)
+			descend = !!(freq > table[i].frequency);
 
-		/*return if level matched and table in descending order*/
-		if (descend && i == level)
-			return table[i].frequency;
-		i++;
+		freq = table[i].frequency;
+		max_level++;
 	}
-	i--;
 
-	if (level > i || descend)
-		return ret;
-	level_index = i - level;
+	/* get max level */
+	if (property == GET_MAXL) {
+		*output = (unsigned int)max_level;
+		return 0;
+	}
 
-	/*Scan the table in reverse order and match the level*/
-	while (i >= 0) {
+	if (property == GET_FREQ)
+		level = descend ? input : (max_level - input - 1);
+
+	for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+		/* ignore invalid entry */
 		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 			continue;
-		/*return if level matched*/
-		if (i == level_index)
-			return table[i].frequency;
-		i--;
+
+		/* ignore duplicate entry */
+		if (freq == table[i].frequency)
+			continue;
+
+		/* now we have a valid frequency entry */
+		freq = table[i].frequency;
+
+		if (property == GET_LEVEL && (unsigned int)input == freq) {
+			/* get level by frequency */
+			*output = descend ? j : (max_level - j - 1);
+			return 0;
+		}
+		if (property == GET_FREQ && level == j) {
+			/* get frequency by level */
+			*output = freq;
+			return 0;
+		}
+		j++;
 	}
-	return ret;
+
+	return -EINVAL;
+}
+
+/**
+ * cpufreq_cooling_get_level - for a give cpu, return the cooling level.
+ * @cpu: cpu for which the level is required
+ * @freq: the frequency of interest
+ *
+ * This function will match the cooling level corresponding to the
+ * requested @freq and return it.
+ *
+ * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
+ * otherwise.
+ */
+unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
+{
+	unsigned int val;
+
+	if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
+		return THERMAL_CSTATE_INVALID;
+
+	return (unsigned long)val;
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
+
+/**
+ * get_cpu_frequency - get the absolute value of frequency from level.
+ * @cpu: cpu for which frequency is fetched.
+ * @level: cooling level
+ *
+ * This function matches cooling level with frequency. Based on a cooling level
+ * of frequency, equals cooling state of cpu cooling device, it will return
+ * the corresponding frequency.
+ *	e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
+ *
+ * Return: 0 on error, the corresponding frequency otherwise.
+ */
+static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
+{
+	int ret = 0;
+	unsigned int freq;
+
+	ret = get_property(cpu, level, &freq, GET_FREQ);
+	if (ret)
+		return 0;
+
+	return freq;
 }
 
 /**
@@ -163,13 +262,19 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
  * @cpufreq_device: cpufreq_cooling_device pointer containing frequency
  *	clipping data.
  * @cooling_state: value of the cooling state.
+ *
+ * Function used to make sure the cpufreq layer is aware of current thermal
+ * limits. The limits are applied by updating the cpufreq policy.
+ *
+ * Return: 0 on success, an error code otherwise (-EINVAL in case wrong
+ * cooling state).
  */
 static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
-				unsigned long cooling_state)
+				 unsigned long cooling_state)
 {
 	unsigned int cpuid, clip_freq;
-	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
-	unsigned int cpu = cpumask_any(maskPtr);
+	struct cpumask *mask = &cpufreq_device->allowed_cpus;
+	unsigned int cpu = cpumask_any(mask);
 
 
 	/* Check if the old cooling action is same as new cooling action */
@@ -184,7 +289,7 @@ static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
 	cpufreq_device->cpufreq_val = clip_freq;
 	notify_device = cpufreq_device;
 
-	for_each_cpu(cpuid, maskPtr) {
+	for_each_cpu(cpuid, mask) {
 		if (is_cpufreq_valid(cpuid))
 			cpufreq_update_policy(cpuid);
 	}
@@ -199,9 +304,15 @@ static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
  * @nb:	struct notifier_block * with callback info.
  * @event: value showing cpufreq event for which this function invoked.
  * @data: callback-specific data
+ *
+ * Callback to highjack the notification on cpufreq policy transition.
+ * Every time there is a change in policy, we will intercept and
+ * update the cpufreq policy with thermal constraints.
+ *
+ * Return: 0 (success)
  */
 static int cpufreq_thermal_notifier(struct notifier_block *nb,
-					unsigned long event, void *data)
+				    unsigned long event, void *data)
 {
 	struct cpufreq_policy *policy = data;
 	unsigned long max_freq = 0;
@@ -212,7 +323,7 @@ static int cpufreq_thermal_notifier(struct notifier_block *nb,
 	if (cpumask_test_cpu(policy->cpu, &notify_device->allowed_cpus))
 		max_freq = notify_device->cpufreq_val;
 
-	/* Never exceed user_policy.max*/
+	/* Never exceed user_policy.max */
 	if (max_freq > policy->user_policy.max)
 		max_freq = policy->user_policy.max;
 
@@ -222,50 +333,46 @@ static int cpufreq_thermal_notifier(struct notifier_block *nb,
 	return 0;
 }
 
-/*
- * cpufreq cooling device callback functions are defined below
- */
+/* cpufreq cooling device callback functions are defined below */
 
 /**
  * cpufreq_get_max_state - callback function to get the max cooling state.
  * @cdev: thermal cooling device pointer.
  * @state: fill this variable with the max cooling state.
+ *
+ * Callback for the thermal cooling device to return the cpufreq
+ * max cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
  */
 static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
 				 unsigned long *state)
 {
 	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
-	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
+	struct cpumask *mask = &cpufreq_device->allowed_cpus;
 	unsigned int cpu;
-	struct cpufreq_frequency_table *table;
-	unsigned long count = 0;
-	int i = 0;
-
-	cpu = cpumask_any(maskPtr);
-	table = cpufreq_frequency_get_table(cpu);
-	if (!table) {
-		*state = 0;
-		return 0;
-	}
+	unsigned int count = 0;
+	int ret;
 
-	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
-		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
-			continue;
-		count++;
-	}
+	cpu = cpumask_any(mask);
 
-	if (count > 0) {
-		*state = --count;
-		return 0;
-	}
+	ret = get_property(cpu, 0, &count, GET_MAXL);
 
-	return -EINVAL;
+	if (count > 0)
+		*state = count;
+
+	return ret;
 }
 
 /**
  * cpufreq_get_cur_state - callback function to get the current cooling state.
  * @cdev: thermal cooling device pointer.
  * @state: fill this variable with the current cooling state.
+ *
+ * Callback for the thermal cooling device to return the cpufreq
+ * current cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
  */
 static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
 				 unsigned long *state)
@@ -273,6 +380,7 @@ static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
 	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
 
 	*state = cpufreq_device->cpufreq_state;
+
 	return 0;
 }
 
@@ -280,6 +388,11 @@ static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
  * cpufreq_set_cur_state - callback function to set the current cooling state.
  * @cdev: thermal cooling device pointer.
  * @state: set this variable to the current cooling state.
+ *
+ * Callback for the thermal cooling device to change the cpufreq
+ * current cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
  */
 static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 				 unsigned long state)
@@ -304,9 +417,16 @@ static struct notifier_block thermal_cpufreq_notifier_block = {
 /**
  * cpufreq_cooling_register - function to create cpufreq cooling device.
  * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ *
+ * This interface function registers the cpufreq cooling device with the name
+ * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ * cooling devices.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
  */
-struct thermal_cooling_device *cpufreq_cooling_register(
-	const struct cpumask *clip_cpus)
+struct thermal_cooling_device *
+cpufreq_cooling_register(const struct cpumask *clip_cpus)
 {
 	struct thermal_cooling_device *cool_dev;
 	struct cpufreq_cooling_device *cpufreq_dev = NULL;
@@ -315,9 +435,9 @@ struct thermal_cooling_device *cpufreq_cooling_register(
 	int ret = 0, i;
 	struct cpufreq_policy policy;
 
-	/*Verify that all the clip cpus have same freq_min, freq_max limit*/
+	/* Verify that all the clip cpus have same freq_min, freq_max limit */
 	for_each_cpu(i, clip_cpus) {
-		/*continue if cpufreq policy not found and not return error*/
+		/* continue if cpufreq policy not found and not return error */
 		if (!cpufreq_get_policy(&policy, i))
 			continue;
 		if (min == 0 && max == 0) {
@@ -325,12 +445,12 @@ struct thermal_cooling_device *cpufreq_cooling_register(
 			max = policy.cpuinfo.max_freq;
 		} else {
 			if (min != policy.cpuinfo.min_freq ||
-				max != policy.cpuinfo.max_freq)
+			    max != policy.cpuinfo.max_freq)
 				return ERR_PTR(-EINVAL);
 		}
 	}
 	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
-			GFP_KERNEL);
+			      GFP_KERNEL);
 	if (!cpufreq_dev)
 		return ERR_PTR(-ENOMEM);
 
@@ -342,10 +462,11 @@ struct thermal_cooling_device *cpufreq_cooling_register(
 		return ERR_PTR(-EINVAL);
 	}
 
-	sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
+	snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
+		 cpufreq_dev->id);
 
 	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
-						&cpufreq_cooling_ops);
+						   &cpufreq_cooling_ops);
 	if (!cool_dev) {
 		release_idr(&cpufreq_idr, cpufreq_dev->id);
 		kfree(cpufreq_dev);
@@ -358,17 +479,20 @@ struct thermal_cooling_device *cpufreq_cooling_register(
 	/* Register the notifier for first cpufreq cooling device */
 	if (cpufreq_dev_count == 0)
 		cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
-						CPUFREQ_POLICY_NOTIFIER);
+					  CPUFREQ_POLICY_NOTIFIER);
 	cpufreq_dev_count++;
 
 	mutex_unlock(&cooling_cpufreq_lock);
+
 	return cool_dev;
 }
-EXPORT_SYMBOL(cpufreq_cooling_register);
+EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
 
 /**
  * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
  * @cdev: thermal cooling device pointer.
+ *
+ * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
  */
 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
 {
@@ -378,14 +502,13 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
 	cpufreq_dev_count--;
 
 	/* Unregister the notifier for the last cpufreq cooling device */
-	if (cpufreq_dev_count == 0) {
+	if (cpufreq_dev_count == 0)
 		cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
-					CPUFREQ_POLICY_NOTIFIER);
-	}
+					    CPUFREQ_POLICY_NOTIFIER);
 	mutex_unlock(&cooling_cpufreq_lock);
 
 	thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
 	release_idr(&cpufreq_idr, cpufreq_dev->id);
 	kfree(cpufreq_dev);
 }
-EXPORT_SYMBOL(cpufreq_cooling_unregister);
+EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);