Initial import

1 files changed, 481 insertions, 0 deletions

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
new file mode 100644
index 000000000..f65f0d109
--- /dev/null
+++ b/drivers/thermal/cpu_cooling.c
@@ -0,0 +1,481 @@
+/*
+ *  linux/drivers/thermal/cpu_cooling.c
+ *
+ *  Copyright (C) 2012	Samsung Electronics Co., Ltd(http://www.samsung.com)
+ *  Copyright (C) 2012  Amit Daniel <amit.kachhap@linaro.org>
+ *
+ *  Copyright (C) 2014  Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  This program is distributed in the hope that 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, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+#include <linux/module.h>
+#include <linux/thermal.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/cpu_cooling.h>
+
+/*
+ * Cooling state <-> CPUFreq frequency
+ *
+ * Cooling states are translated to frequencies throughout this driver and this
+ * is the relation between them.
+ *
+ * Highest cooling state corresponds to lowest possible frequency.
+ *
+ * i.e.
+ *	level 0 --> 1st Max Freq
+ *	level 1 --> 2nd Max Freq
+ *	...
+ */
+
+/**
+ * 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
+ *	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.
+ * @max_level: maximum cooling level. One less than total number of valid
+ *	cpufreq frequencies.
+ * @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 registered
+ * cpufreq_cooling_device.
+ */
+struct cpufreq_cooling_device {
+	int id;
+	struct thermal_cooling_device *cool_dev;
+	unsigned int cpufreq_state;
+	unsigned int cpufreq_val;
+	unsigned int max_level;
+	unsigned int *freq_table;	/* In descending order */
+	struct cpumask allowed_cpus;
+	struct list_head node;
+};
+static DEFINE_IDR(cpufreq_idr);
+static DEFINE_MUTEX(cooling_cpufreq_lock);
+
+static LIST_HEAD(cpufreq_dev_list);
+
+/**
+ * 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)
+{
+	int ret;
+
+	mutex_lock(&cooling_cpufreq_lock);
+	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
+	mutex_unlock(&cooling_cpufreq_lock);
+	if (unlikely(ret < 0))
+		return ret;
+	*id = ret;
+
+	return 0;
+}
+
+/**
+ * release_idr - function to free the unique id.
+ * @idr: struct idr * handle used for creating the id.
+ * @id: int value representing the unique id.
+ */
+static void release_idr(struct idr *idr, int id)
+{
+	mutex_lock(&cooling_cpufreq_lock);
+	idr_remove(idr, id);
+	mutex_unlock(&cooling_cpufreq_lock);
+}
+
+/* Below code defines functions to be used for cpufreq as cooling device */
+
+/**
+ * get_level: Find the level for a particular frequency
+ * @cpufreq_dev: cpufreq_dev for which the property is required
+ * @freq: Frequency
+ *
+ * Return: level on success, THERMAL_CSTATE_INVALID on error.
+ */
+static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_dev,
+			       unsigned int freq)
+{
+	unsigned long level;
+
+	for (level = 0; level <= cpufreq_dev->max_level; level++) {
+		if (freq == cpufreq_dev->freq_table[level])
+			return level;
+
+		if (freq > cpufreq_dev->freq_table[level])
+			break;
+	}
+
+	return THERMAL_CSTATE_INVALID;
+}
+
+/**
+ * cpufreq_cooling_get_level - for a given 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)
+{
+	struct cpufreq_cooling_device *cpufreq_dev;
+
+	mutex_lock(&cooling_cpufreq_lock);
+	list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
+		if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) {
+			mutex_unlock(&cooling_cpufreq_lock);
+			return get_level(cpufreq_dev, freq);
+		}
+	}
+	mutex_unlock(&cooling_cpufreq_lock);
+
+	pr_err("%s: cpu:%d not part of any cooling device\n", __func__, cpu);
+	return THERMAL_CSTATE_INVALID;
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
+
+/**
+ * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
+ * @nb:	struct notifier_block * with callback info.
+ * @event: value showing cpufreq event for which this function invoked.
+ * @data: callback-specific data
+ *
+ * Callback to hijack 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)
+{
+	struct cpufreq_policy *policy = data;
+	unsigned long max_freq = 0;
+	struct cpufreq_cooling_device *cpufreq_dev;
+
+	if (event != CPUFREQ_ADJUST)
+		return 0;
+
+	mutex_lock(&cooling_cpufreq_lock);
+	list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
+		if (!cpumask_test_cpu(policy->cpu,
+					&cpufreq_dev->allowed_cpus))
+			continue;
+
+		max_freq = cpufreq_dev->cpufreq_val;
+
+		if (policy->max != max_freq)
+			cpufreq_verify_within_limits(policy, 0, max_freq);
+	}
+	mutex_unlock(&cooling_cpufreq_lock);
+
+	return 0;
+}
+
+/* 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;
+
+	*state = cpufreq_device->max_level;
+	return 0;
+}
+
+/**
+ * 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)
+{
+	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
+
+	*state = cpufreq_device->cpufreq_state;
+
+	return 0;
+}
+
+/**
+ * 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)
+{
+	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
+	unsigned int cpu = cpumask_any(&cpufreq_device->allowed_cpus);
+	unsigned int clip_freq;
+
+	/* Request state should be less than max_level */
+	if (WARN_ON(state > cpufreq_device->max_level))
+		return -EINVAL;
+
+	/* Check if the old cooling action is same as new cooling action */
+	if (cpufreq_device->cpufreq_state == state)
+		return 0;
+
+	clip_freq = cpufreq_device->freq_table[state];
+	cpufreq_device->cpufreq_state = state;
+	cpufreq_device->cpufreq_val = clip_freq;
+
+	cpufreq_update_policy(cpu);
+
+	return 0;
+}
+
+/* Bind cpufreq callbacks to thermal cooling device ops */
+static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
+	.get_max_state = cpufreq_get_max_state,
+	.get_cur_state = cpufreq_get_cur_state,
+	.set_cur_state = cpufreq_set_cur_state,
+};
+
+/* Notifier for cpufreq policy change */
+static struct notifier_block thermal_cpufreq_notifier_block = {
+	.notifier_call = cpufreq_thermal_notifier,
+};
+
+static unsigned int find_next_max(struct cpufreq_frequency_table *table,
+				  unsigned int prev_max)
+{
+	struct cpufreq_frequency_table *pos;
+	unsigned int max = 0;
+
+	cpufreq_for_each_valid_entry(pos, table) {
+		if (pos->frequency > max && pos->frequency < prev_max)
+			max = pos->frequency;
+	}
+
+	return max;
+}
+
+/**
+ * __cpufreq_cooling_register - helper function to create cpufreq cooling device
+ * @np: a valid struct device_node to the cooling device device tree node
+ * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ * Normally this should be same as cpufreq policy->related_cpus.
+ *
+ * This interface function registers the cpufreq cooling device with the name
+ * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ * cooling devices. It also gives the opportunity to link the cooling device
+ * with a device tree node, in order to bind it via the thermal DT code.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
+ */
+static struct thermal_cooling_device *
+__cpufreq_cooling_register(struct device_node *np,
+			   const struct cpumask *clip_cpus)
+{
+	struct thermal_cooling_device *cool_dev;
+	struct cpufreq_cooling_device *cpufreq_dev;
+	char dev_name[THERMAL_NAME_LENGTH];
+	struct cpufreq_frequency_table *pos, *table;
+	unsigned int freq, i;
+	int ret;
+
+	table = cpufreq_frequency_get_table(cpumask_first(clip_cpus));
+	if (!table) {
+		pr_debug("%s: CPUFreq table not found\n", __func__);
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL);
+	if (!cpufreq_dev)
+		return ERR_PTR(-ENOMEM);
+
+	/* Find max levels */
+	cpufreq_for_each_valid_entry(pos, table)
+		cpufreq_dev->max_level++;
+
+	cpufreq_dev->freq_table = kmalloc(sizeof(*cpufreq_dev->freq_table) *
+					  cpufreq_dev->max_level, GFP_KERNEL);
+	if (!cpufreq_dev->freq_table) {
+		cool_dev = ERR_PTR(-ENOMEM);
+		goto free_cdev;
+	}
+
+	/* max_level is an index, not a counter */
+	cpufreq_dev->max_level--;
+
+	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
+
+	ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
+	if (ret) {
+		cool_dev = ERR_PTR(ret);
+		goto free_table;
+	}
+
+	snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
+		 cpufreq_dev->id);
+
+	cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,
+						      &cpufreq_cooling_ops);
+	if (IS_ERR(cool_dev))
+		goto remove_idr;
+
+	/* Fill freq-table in descending order of frequencies */
+	for (i = 0, freq = -1; i <= cpufreq_dev->max_level; i++) {
+		freq = find_next_max(table, freq);
+		cpufreq_dev->freq_table[i] = freq;
+
+		/* Warn for duplicate entries */
+		if (!freq)
+			pr_warn("%s: table has duplicate entries\n", __func__);
+		else
+			pr_debug("%s: freq:%u KHz\n", __func__, freq);
+	}
+
+	cpufreq_dev->cpufreq_val = cpufreq_dev->freq_table[0];
+	cpufreq_dev->cool_dev = cool_dev;
+
+	mutex_lock(&cooling_cpufreq_lock);
+
+	/* Register the notifier for first cpufreq cooling device */
+	if (list_empty(&cpufreq_dev_list))
+		cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
+					  CPUFREQ_POLICY_NOTIFIER);
+	list_add(&cpufreq_dev->node, &cpufreq_dev_list);
+
+	mutex_unlock(&cooling_cpufreq_lock);
+
+	return cool_dev;
+
+remove_idr:
+	release_idr(&cpufreq_idr, cpufreq_dev->id);
+free_table:
+	kfree(cpufreq_dev->freq_table);
+free_cdev:
+	kfree(cpufreq_dev);
+
+	return cool_dev;
+}
+
+/**
+ * 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)
+{
+	return __cpufreq_cooling_register(NULL, clip_cpus);
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
+
+/**
+ * of_cpufreq_cooling_register - function to create cpufreq cooling device.
+ * @np: a valid struct device_node to the cooling device device tree node
+ * @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. Using this API, the cpufreq cooling device will be
+ * linked to the device tree node provided.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
+ */
+struct thermal_cooling_device *
+of_cpufreq_cooling_register(struct device_node *np,
+			    const struct cpumask *clip_cpus)
+{
+	if (!np)
+		return ERR_PTR(-EINVAL);
+
+	return __cpufreq_cooling_register(np, clip_cpus);
+}
+EXPORT_SYMBOL_GPL(of_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)
+{
+	struct cpufreq_cooling_device *cpufreq_dev;
+
+	if (!cdev)
+		return;
+
+	cpufreq_dev = cdev->devdata;
+	mutex_lock(&cooling_cpufreq_lock);
+	list_del(&cpufreq_dev->node);
+
+	/* Unregister the notifier for the last cpufreq cooling device */
+	if (list_empty(&cpufreq_dev_list))
+		cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
+					    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->freq_table);
+	kfree(cpufreq_dev);
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);