5 files changed, 552 insertions, 0 deletions

diff --git a/Documentation/thermal/cpu-cooling-api.txt b/Documentation/thermal/cpu-cooling-api.txt
new file mode 100644
index 000000000000..fca24c931ec8
--- /dev/null
+++ b/Documentation/thermal/cpu-cooling-api.txt
@@ -0,0 +1,32 @@
+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) 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 cpumask *clip_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.
+
+   clip_cpus: cpumask of cpus where the frequency constraints will happen.
+
+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.
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 7dd8c34552e1..996003b3438a 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -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
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index fd9369aeb96f..aae59ad57c42 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -3,5 +3,6 @@
 #
 
 obj-$(CONFIG_THERMAL)           += thermal_sys.o
+obj-$(CONFIG_CPU_THERMAL)               += cpu_cooling.o
 obj-$(CONFIG_SPEAR_THERMAL)             += spear_thermal.o
 obj-$(CONFIG_RCAR_THERMAL)      += rcar_thermal.o
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
new file mode 100644
index 000000000000..99a5d7551b33
--- /dev/null
+++ b/drivers/thermal/cpu_cooling.c
@@ -0,0 +1,450 @@
+/*
+ *  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_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);
+}
+
+/* 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, id = 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->id = id;
+        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);
diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
new file mode 100644
index 000000000000..851530128e65
--- /dev/null
+++ b/include/linux/cpu_cooling.h
@@ -0,0 +1,58 @@
+/*
+ *  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
+
+#ifdef CONFIG_CPU_THERMAL
+/**
+ * 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);
+
+/**
+ * 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_THERMAL */
+static inline struct thermal_cooling_device *cpufreq_cooling_register(
+        struct cpumask *clip_cpus)
+{
+        return NULL;
+}
+static inline void cpufreq_cooling_unregister(
+                struct thermal_cooling_device *cdev)
+{
+        return;
+}
+#endif  /* CONFIG_CPU_THERMAL */
+
+#endif /* __CPU_COOLING_H__ */