diff options
Diffstat (limited to 'drivers/thermal/cpu_cooling.c')
| -rw-r--r-- | drivers/thermal/cpu_cooling.c | 449 |
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 000000000000..cc1c930a90e4 --- /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, ¬ify_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); |