new file mode 100644
@@ -0,0 +1,60 @@
+CPU cooling APIs How To
+===================================
+
+Written by Amit Daniel Kachhap <amit.kachhap@linaro.org>
+
+Updated: 12 May 2012
+
+Copyright (c) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
+
+0. Introduction
+
+The generic cpu cooling(freq clipping, cpuhotplug etc) provides
+registration/unregistration APIs to the caller. The binding of the cooling
+devices to the trip point is left for the user. The registration APIs returns
+the cooling device pointer.
+
+1. cpu cooling APIs
+
+1.1 cpufreq registration/unregistration APIs
+1.1.1 struct thermal_cooling_device *cpufreq_cooling_register(
+ struct freq_clip_table *tab_ptr, unsigned int tab_size)
+
+ This interface function registers the cpufreq cooling device with the name
+ "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ cooling devices.
+
+ tab_ptr: The table containing the maximum value of frequency to be clipped
+ for each cooling state.
+ .freq_clip_max: Value of frequency to be clipped for each allowed
+ cpus.
+ .temp_level: Temperature level at which the frequency clamping will
+ happen.
+ .mask_val: cpumask of the allowed cpu's
+ tab_size: the total number of cpufreq cooling states.
+
+1.1.2 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
+
+ This interface function unregisters the "thermal-cpufreq-%x" cooling device.
+
+ cdev: Cooling device pointer which has to be unregistered.
+
+
+1.2 CPU cooling action notifier register/unregister interface
+1.2.1 int cputherm_register_notifier(struct notifier_block *nb,
+ unsigned int list)
+
+ This interface registers a driver with cpu cooling layer. The driver will
+ be notified when any cpu cooling action is called.
+
+ nb: notifier function to register
+ list: CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP
+
+1.2.2 int cputherm_unregister_notifier(struct notifier_block *nb,
+ unsigned int list)
+
+ This interface registers a driver with cpu cooling layer. The driver will
+ be notified when any cpu cooling action is called.
+
+ nb: notifier function to register
+ list: CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP
@@ -19,6 +19,17 @@ config THERMAL_HWMON
depends on HWMON=y || HWMON=THERMAL
default y
+config CPU_THERMAL
+ bool "generic cpu cooling support"
+ depends on THERMAL && CPU_FREQ
+ help
+ This implements the generic cpu cooling mechanism through frequency
+ reduction, cpu hotplug and any other ways of reducing temperature. An
+ ACPI version of this already exists(drivers/acpi/processor_thermal.c).
+ This will be useful for platforms using the generic thermal interface
+ and not the ACPI interface.
+ If you want this support, you should say Y here.
+
config SPEAR_THERMAL
bool "SPEAr thermal sensor driver"
depends on THERMAL
@@ -3,4 +3,5 @@
#
obj-$(CONFIG_THERMAL) += thermal_sys.o
-obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
\ No newline at end of file
+obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o
+obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
new file mode 100644
@@ -0,0 +1,483 @@
+/*
+ * 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>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * 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/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>
+#include <linux/cpu.h>
+#include <linux/cpu_cooling.h>
+
+/**
+ * struct cpufreq_cooling_device
+ * @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.
+ * @tab_ptr: freq_clip_table table containing the maximum value of frequency to
+ * be set for different cooling state.
+ * @tab_size: integer value representing a count of the above table.
+ * @cpufreq_state: integer value representing the current state of cpufreq
+ * cooling devices.
+ * @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
+ * mutex lock cooling_cpufreq_lock is used.
+ */
+struct cpufreq_cooling_device {
+ int id;
+ struct thermal_cooling_device *cool_dev;
+ struct freq_clip_table *tab_ptr;
+ unsigned int tab_size;
+ unsigned int cpufreq_state;
+ struct cpumask allowed_cpus;
+ struct list_head node;
+};
+static LIST_HEAD(cooling_cpufreq_list);
+static DEFINE_MUTEX(cooling_cpufreq_lock);
+static DEFINE_IDR(cpufreq_idr);
+
+/* per cpu variable to store the previous max frequency allowed */
+static DEFINE_PER_CPU(unsigned int, max_policy_freq);
+
+/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
+#define NOTIFY_INVALID NULL
+static struct freq_clip_table *notify_table;
+
+/* Head of the blocking notifier chain to inform about frequency clamping */
+static BLOCKING_NOTIFIER_HEAD(cputherm_state_notifier_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.
+ */
+static int get_idr(struct idr *idr, int *id)
+{
+ int err;
+again:
+ if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0))
+ return -ENOMEM;
+
+ mutex_lock(&cooling_cpufreq_lock);
+ err = idr_get_new(idr, NULL, id);
+ mutex_unlock(&cooling_cpufreq_lock);
+
+ if (unlikely(err == -EAGAIN))
+ goto again;
+ else if (unlikely(err))
+ return err;
+
+ *id = *id & MAX_ID_MASK;
+ 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);
+}
+
+/**
+ * cputherm_register_notifier - Register a notifier with cpu cooling interface.
+ * @nb: struct notifier_block * with callback info.
+ * @list: integer value for which notification is needed. possible values are
+ * CPUFREQ_COOLING_START and CPUFREQ_COOLING_STOP.
+ *
+ * This exported function registers a driver with cpu cooling layer. The driver
+ * will be notified when any cpu cooling action is called.
+ */
+int cputherm_register_notifier(struct notifier_block *nb, unsigned int list)
+{
+ int ret = 0;
+
+ switch (list) {
+ case CPUFREQ_COOLING_START:
+ case CPUFREQ_COOLING_STOP:
+ ret = blocking_notifier_chain_register(
+ &cputherm_state_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ return ret;
+}
+EXPORT_SYMBOL(cputherm_register_notifier);
+
+/**
+ * cputherm_unregister_notifier - Un-register a notifier.
+ * @nb: struct notifier_block * with callback info.
+ * @list: integer value for which notification is needed. values possible are
+ * CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP.
+ *
+ * This exported function un-registers a driver with cpu cooling layer.
+ */
+int cputherm_unregister_notifier(struct notifier_block *nb, unsigned int list)
+{
+ int ret = 0;
+
+ switch (list) {
+ case CPUFREQ_COOLING_START:
+ case CPUFREQ_COOLING_STOP:
+ ret = blocking_notifier_chain_unregister(
+ &cputherm_state_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ return ret;
+}
+EXPORT_SYMBOL(cputherm_unregister_notifier);
+
+/* 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.
+ * @cpu: cpu for which check is needed.
+ */
+static int is_cpufreq_valid(int cpu)
+{
+ struct cpufreq_policy policy;
+ return !cpufreq_get_policy(&policy, cpu);
+}
+
+/**
+ * cpufreq_apply_cooling - function to apply frequency clipping.
+ * @cpufreq_device: cpufreq_cooling_device pointer containing frequency
+ * clipping data.
+ * @cooling_state: value of the cooling state.
+ */
+static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
+ unsigned long cooling_state)
+{
+ unsigned int event, cpuid, state;
+ struct freq_clip_table *th_table, *table_ptr;
+ const struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
+ struct cpufreq_cooling_device *cpufreq_ptr;
+
+ if (cooling_state > cpufreq_device->tab_size)
+ return -EINVAL;
+
+ /* Check if the old cooling action is same as new cooling action */
+ if (cpufreq_device->cpufreq_state == cooling_state)
+ return 0;
+
+ /* pass cooling table info to the cpufreq_thermal_notifier callback */
+ notify_table = NOTIFY_INVALID;
+
+ if (cooling_state > 0) {
+ th_table = &(cpufreq_device->tab_ptr[cooling_state - 1]);
+ notify_table = th_table;
+ }
+
+ /* check if any lower clip frequency active in other cpufreq_device's */
+ list_for_each_entry(cpufreq_ptr, &cooling_cpufreq_list, node) {
+
+ state = cpufreq_ptr->cpufreq_state;
+ if (state == 0 || cpufreq_ptr == cpufreq_device)
+ continue;
+
+ if (!cpumask_equal(&cpufreq_ptr->allowed_cpus,
+ &cpufreq_device->allowed_cpus))
+ continue;
+
+ table_ptr = &(cpufreq_ptr->tab_ptr[state - 1]);
+ if (notify_table == NULL ||
+ (table_ptr->freq_clip_max <
+ notify_table->freq_clip_max))
+ notify_table = table_ptr;
+ }
+
+ cpufreq_device->cpufreq_state = cooling_state;
+
+ if (notify_table != NOTIFY_INVALID) {
+ event = CPUFREQ_COOLING_START;
+ maskPtr = notify_table->mask_val;
+ } else {
+ event = CPUFREQ_COOLING_STOP;
+ }
+
+ blocking_notifier_call_chain(&cputherm_state_notifier_list,
+ event, notify_table);
+
+ for_each_cpu(cpuid, maskPtr) {
+ if (is_cpufreq_valid(cpuid))
+ cpufreq_update_policy(cpuid);
+ }
+
+ notify_table = NOTIFY_INVALID;
+
+ return 0;
+}
+
+/**
+ * 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
+ */
+static int cpufreq_thermal_notifier(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct cpufreq_policy *policy = data;
+ unsigned long max_freq = 0;
+
+ if (event != CPUFREQ_ADJUST)
+ return 0;
+
+ if (notify_table != NOTIFY_INVALID) {
+ max_freq = notify_table->freq_clip_max;
+
+ if (!per_cpu(max_policy_freq, policy->cpu))
+ per_cpu(max_policy_freq, policy->cpu) = policy->max;
+ } else {
+ if (per_cpu(max_policy_freq, policy->cpu)) {
+ max_freq = per_cpu(max_policy_freq, policy->cpu);
+ per_cpu(max_policy_freq, policy->cpu) = 0;
+ } else {
+ max_freq = policy->max;
+ }
+ }
+
+ /* Never exceed user_policy.max*/
+ if (max_freq > policy->user_policy.max)
+ max_freq = policy->user_policy.max;
+
+ if (policy->max != max_freq)
+ cpufreq_verify_within_limits(policy, 0, max_freq);
+
+ 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.
+ */
+static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ int ret = -EINVAL;
+ struct cpufreq_cooling_device *cpufreq_device;
+
+ mutex_lock(&cooling_cpufreq_lock);
+ list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
+ if (cpufreq_device && cpufreq_device->cool_dev == cdev) {
+ *state = cpufreq_device->tab_size;
+ ret = 0;
+ break;
+ }
+ }
+ mutex_unlock(&cooling_cpufreq_lock);
+ 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.
+ */
+static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ int ret = -EINVAL;
+ struct cpufreq_cooling_device *cpufreq_device;
+
+ mutex_lock(&cooling_cpufreq_lock);
+ list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
+ if (cpufreq_device && cpufreq_device->cool_dev == cdev) {
+ *state = cpufreq_device->cpufreq_state;
+ ret = 0;
+ break;
+ }
+ }
+ mutex_unlock(&cooling_cpufreq_lock);
+ return ret;
+}
+
+/**
+ * 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.
+ */
+static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long state)
+{
+ int ret = -EINVAL;
+ struct cpufreq_cooling_device *cpufreq_device;
+
+ mutex_lock(&cooling_cpufreq_lock);
+ list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
+ if (cpufreq_device && cpufreq_device->cool_dev == cdev) {
+ ret = 0;
+ break;
+ }
+ }
+ if (!ret)
+ ret = cpufreq_apply_cooling(cpufreq_device, state);
+
+ mutex_unlock(&cooling_cpufreq_lock);
+
+ return ret;
+}
+
+/* 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,
+};
+
+/**
+ * cpufreq_cooling_register - function to create cpufreq cooling device.
+ * @tab_ptr: table ptr containing the maximum value of frequency to be clipped
+ * for each cooling state.
+ * @tab_size: count of entries in the above table.
+ * happen.
+ */
+struct thermal_cooling_device *cpufreq_cooling_register(
+ struct freq_clip_table *tab_ptr, unsigned int tab_size)
+{
+ struct thermal_cooling_device *cool_dev;
+ struct cpufreq_cooling_device *cpufreq_dev = NULL;
+ struct freq_clip_table *clip_tab;
+ unsigned int cpufreq_dev_count = 0;
+ char dev_name[THERMAL_NAME_LENGTH];
+ int ret = 0, id = 0, i;
+
+ if (tab_ptr == NULL || tab_size == 0)
+ return ERR_PTR(-EINVAL);
+
+ list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node)
+ cpufreq_dev_count++;
+
+ cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
+ GFP_KERNEL);
+ if (!cpufreq_dev)
+ return ERR_PTR(-ENOMEM);
+
+ /* Verify that all the entries of freq_clip_table are present */
+ for (i = 0; i < tab_size; i++) {
+ clip_tab = ((struct freq_clip_table *)&tab_ptr[i]);
+ if (!clip_tab->freq_clip_max || !clip_tab->mask_val
+ || !clip_tab->temp_level) {
+ kfree(cpufreq_dev);
+ return ERR_PTR(-EINVAL);
+ }
+ /*
+ * Consolidate all the cpumask for all the individual entries
+ * of the trip table. This is useful in resetting all the
+ * clipped frequencies to the normal level for each cpufreq
+ * cooling device.
+ */
+ cpumask_or(&cpufreq_dev->allowed_cpus,
+ &cpufreq_dev->allowed_cpus, clip_tab->mask_val);
+ }
+
+ cpufreq_dev->tab_ptr = tab_ptr;
+ cpufreq_dev->tab_size = tab_size;
+
+ ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
+ if (ret) {
+ kfree(cpufreq_dev);
+ return ERR_PTR(-EINVAL);
+ }
+
+ sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
+
+ cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
+ &cpufreq_cooling_ops);
+ if (!cool_dev) {
+ release_idr(&cpufreq_idr, cpufreq_dev->id);
+ kfree(cpufreq_dev);
+ return ERR_PTR(-EINVAL);
+ }
+ cpufreq_dev->id = id;
+ cpufreq_dev->cool_dev = cool_dev;
+ mutex_lock(&cooling_cpufreq_lock);
+ list_add_tail(&cpufreq_dev->node, &cooling_cpufreq_list);
+
+ /* Register the notifier for first cpufreq cooling device */
+ if (cpufreq_dev_count == 0)
+ cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
+ CPUFREQ_POLICY_NOTIFIER);
+
+ mutex_unlock(&cooling_cpufreq_lock);
+ return cool_dev;
+}
+EXPORT_SYMBOL(cpufreq_cooling_register);
+
+/**
+ * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
+ * @cdev: thermal cooling device pointer.
+ */
+void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
+{
+ struct cpufreq_cooling_device *cpufreq_dev = NULL;
+ unsigned int cpufreq_dev_count = 0;
+
+ mutex_lock(&cooling_cpufreq_lock);
+ list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node) {
+ if (cpufreq_dev && cpufreq_dev->cool_dev == cdev)
+ break;
+ cpufreq_dev_count++;
+ }
+
+ if (!cpufreq_dev || cpufreq_dev->cool_dev != cdev) {
+ mutex_unlock(&cooling_cpufreq_lock);
+ return;
+ }
+
+ list_del(&cpufreq_dev->node);
+
+ /* Unregister the notifier for the last cpufreq cooling device */
+ if (cpufreq_dev_count == 1) {
+ 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);
+}
+EXPORT_SYMBOL(cpufreq_cooling_unregister);
new file mode 100644
@@ -0,0 +1,99 @@
+/*
+ * linux/include/linux/cpu_cooling.h
+ *
+ * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
+ * Copyright (C) 2012 Amit Daniel <amit.kachhap@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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef __CPU_COOLING_H__
+#define __CPU_COOLING_H__
+
+#include <linux/thermal.h>
+
+#define CPUFREQ_COOLING_START 0
+#define CPUFREQ_COOLING_STOP 1
+
+/**
+ * struct freq_clip_table
+ * @freq_clip_max: maximum frequency allowed for this cooling state.
+ * @temp_level: Temperature level at which the temperature clipping will
+ * happen.
+ * @mask_val: cpumask of the allowed cpu's where the clipping will take place.
+ *
+ * This structure is required to be filled and passed to the
+ * cpufreq_cooling_unregister function.
+ */
+struct freq_clip_table {
+ unsigned int freq_clip_max;
+ unsigned int temp_level;
+ const struct cpumask *mask_val;
+};
+
+/**
+ * cputherm_register_notifier - Register a notifier with cpu cooling interface.
+ * @nb: struct notifier_block * with callback info.
+ * @list: integer value for which notification is needed. possible values are
+ * CPUFREQ_COOLING_START and CPUFREQ_COOLING_STOP.
+ *
+ * This exported function registers a driver with cpu cooling layer. The driver
+ * will be notified when any cpu cooling action is called.
+ */
+int cputherm_register_notifier(struct notifier_block *nb, unsigned int list);
+
+/**
+ * cputherm_unregister_notifier - Un-register a notifier.
+ * @nb: struct notifier_block * with callback info.
+ * @list: integer value for which notification is needed. values possible are
+ * CPUFREQ_COOLING_START and CPUFREQ_COOLING_STOP.
+ *
+ * This exported function un-registers a driver with cpu cooling layer.
+ */
+int cputherm_unregister_notifier(struct notifier_block *nb, unsigned int list);
+
+#ifdef CONFIG_CPU_FREQ
+/**
+ * cpufreq_cooling_register - function to create cpufreq cooling device.
+ * @tab_ptr: table ptr containing the maximum value of frequency to be clipped
+ * for each cooling state.
+ * @tab_size: count of entries in the above table.
+ * @mask_val: cpumask containing the allowed cpu's where frequency clipping can
+ * happen.
+ */
+struct thermal_cooling_device *cpufreq_cooling_register(
+ struct freq_clip_table *tab_ptr, unsigned int tab_size);
+
+/**
+ * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
+ * @cdev: thermal cooling device pointer.
+ */
+void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
+#else /* !CONFIG_CPU_FREQ */
+static inline struct thermal_cooling_device *cpufreq_cooling_register(
+ struct freq_clip_table *tab_ptr, unsigned int tab_size)
+{
+ return NULL;
+}
+static inline void cpufreq_cooling_unregister(
+ struct thermal_cooling_device *cdev)
+{
+ return;
+}
+#endif /* CONFIG_CPU_FREQ */
+
+#endif /* __CPU_COOLING_H__ */