1 files changed, 449 insertions, 0 deletions
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
new file mode 100644
index 00000000000..cc1c930a90e
--- /dev/null
+++ b/drivers/thermal/cpu_cooling.c
@@ -0,0 +1,449 @@
+/*
+ *  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.
+ * @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
+ * mutex lock cooling_cpufreq_lock is used.
+ */
+struct cpufreq_cooling_device {
+	int id;
+	struct thermal_cooling_device *cool_dev;
+	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 struct mutex cooling_cpufreq_lock;
+
+/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
+#define NOTIFY_INVALID NULL
+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.
+ */
+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_IDR_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);
+}
+
+/* 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);
+}
+
+/**
+ * get_cpu_frequency - get the absolute value of frequency from level.
+ * @cpu: cpu for which frequency is fetched.
+ * @level: level of frequency of the CPU
+ *	e.g level=1 --> 1st MAX FREQ, LEVEL=2 ---> 2nd MAX FREQ, .... etc
+ */
+static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
+{
+	int ret = 0, i = 0;
+	unsigned long level_index;
+	bool descend = false;
+	struct cpufreq_frequency_table *table =
+					cpufreq_frequency_get_table(cpu);
+	if (!table)
+		return ret;
+
+	while (table[i].frequency != CPUFREQ_TABLE_END) {
+		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;
+		}
+
+		/*return if level matched and table in descending order*/
+		if (descend && i == level)
+			return table[i].frequency;
+		i++;
+	}
+	i--;
+
+	if (level > i || descend)
+		return ret;
+	level_index = i - level;
+
+	/*Scan the table in reverse order and match the level*/
+	while (i >= 0) {
+		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
+			continue;
+		/*return if level matched*/
+		if (i == level_index)
+			return table[i].frequency;
+		i--;
+	}
+	return ret;
+}
+
+/**
+ * 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 cpuid, clip_freq;
+	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
+	unsigned int cpu = cpumask_any(maskPtr);
+
+
+	/* Check if the old cooling action is same as new cooling action */
+	if (cpufreq_device->cpufreq_state == cooling_state)
+		return 0;
+
+	clip_freq = get_cpu_frequency(cpu, cooling_state);
+	if (!clip_freq)
+		return -EINVAL;
+
+	cpufreq_device->cpufreq_state = cooling_state;
+	cpufreq_device->cpufreq_val = clip_freq;
+	notify_device = cpufreq_device;
+
+	for_each_cpu(cpuid, maskPtr) {
+		if (is_cpufreq_valid(cpuid))
+			cpufreq_update_policy(cpuid);
+	}
+
+	notify_device = 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 || notify_device == NOTIFY_INVALID)
+		return 0;
+
+	if (cpumask_test_cpu(policy->cpu, &notify_device->allowed_cpus))
+		max_freq = notify_device->cpufreq_val;
+
+	/* 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, i = 0;
+	struct cpufreq_cooling_device *cpufreq_device;
+	struct cpumask *maskPtr;
+	unsigned int cpu;
+	struct cpufreq_frequency_table *table;
+
+	mutex_lock(&cooling_cpufreq_lock);
+	list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
+		if (cpufreq_device && cpufreq_device->cool_dev == cdev)
+			break;
+	}
+	if (cpufreq_device == NULL)
+		goto return_get_max_state;
+
+	maskPtr = &cpufreq_device->allowed_cpus;
+	cpu = cpumask_any(maskPtr);
+	table = cpufreq_frequency_get_table(cpu);
+	if (!table) {
+		*state = 0;
+		ret = 0;
+		goto return_get_max_state;
+	}
+
+	while (table[i].frequency != CPUFREQ_TABLE_END) {
+		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
+			continue;
+		i++;
+	}
+	if (i > 0) {
+		*state = --i;
+		ret = 0;
+	}
+
+return_get_max_state:
+	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.
+ * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ */
+struct thermal_cooling_device *cpufreq_cooling_register(
+	struct cpumask *clip_cpus)
+{
+	struct thermal_cooling_device *cool_dev;
+	struct cpufreq_cooling_device *cpufreq_dev = NULL;
+	unsigned int cpufreq_dev_count = 0, min = 0, max = 0;
+	char dev_name[THERMAL_NAME_LENGTH];
+	int ret = 0, i;
+	struct cpufreq_policy policy;
+
+	list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node)
+		cpufreq_dev_count++;
+
+	/*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*/
+		if (!cpufreq_get_policy(&policy, i))
+			continue;
+		if (min == 0 && max == 0) {
+			min = policy.cpuinfo.min_freq;
+			max = policy.cpuinfo.max_freq;
+		} else {
+			if (min != policy.cpuinfo.min_freq ||
+				max != policy.cpuinfo.max_freq)
+				return ERR_PTR(-EINVAL);
+}
+	}
+	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
+			GFP_KERNEL);
+	if (!cpufreq_dev)
+		return ERR_PTR(-ENOMEM);
+
+	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
+
+	if (cpufreq_dev_count == 0)
+		mutex_init(&cooling_cpufreq_lock);
+
+	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->cool_dev = cool_dev;
+	cpufreq_dev->cpufreq_state = 0;
+	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);
+	if (cpufreq_dev_count == 1)
+		mutex_destroy(&cooling_cpufreq_lock);
+	kfree(cpufreq_dev);
+}
+EXPORT_SYMBOL(cpufreq_cooling_unregister);