diff options
Diffstat (limited to 'drivers/thermal/cpu_cooling.c')
| -rw-r--r-- | drivers/thermal/cpu_cooling.c | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c new file mode 100644 index 00000000000..84a75f89bf7 --- /dev/null +++ b/drivers/thermal/cpu_cooling.c @@ -0,0 +1,564 @@ +/* + * 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/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> + +/** + * 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. + * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device. + * + * This structure is required for keeping information of each + * cpufreq_cooling_device registered. In order to prevent corruption of this 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; +}; +static DEFINE_IDR(cpufreq_idr); +static DEFINE_MUTEX(cooling_cpufreq_lock); + +static unsigned int cpufreq_dev_count; + +/* notify_table passes value to the CPUFREQ_ADJUST callback function. */ +#define NOTIFY_INVALID NULL +static 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. + * + * 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 */ + +/** + * is_cpufreq_valid - function to check frequency transitioning capability. + * @cpu: cpu for which check is needed. + * + * This function will check the current state of the system if + * it is capable of changing the frequency for a given @cpu. + * + * Return: 0 if the system is not currently capable of changing + * the frequency of given cpu. !0 in case the frequency is changeable. + */ +static int is_cpufreq_valid(int cpu) +{ + struct cpufreq_policy policy; + + return !cpufreq_get_policy(&policy, cpu); +} + +enum cpufreq_cooling_property { + GET_LEVEL, + GET_FREQ, + GET_MAXL, +}; + +/** + * get_property - fetch a property of interest for a give cpu. + * @cpu: cpu for which the property is required + * @input: query parameter + * @output: query return + * @property: type of query (frequency, level, max level) + * + * This is the common function to + * 1. get maximum cpu cooling states + * 2. translate frequency to cooling state + * 3. translate cooling state to frequency + * Note that the code may be not in good shape + * but it is written in this way in order to: + * a) reduce duplicate code as most of the code can be shared. + * b) make sure the logic is consistent when translating between + * cooling states and frequencies. + * + * Return: 0 on success, -EINVAL when invalid parameters are passed. + */ +static int get_property(unsigned int cpu, unsigned long input, + unsigned int *output, + enum cpufreq_cooling_property property) +{ + int i; + unsigned long max_level = 0, level = 0; + unsigned int freq = CPUFREQ_ENTRY_INVALID; + int descend = -1; + struct cpufreq_frequency_table *pos, *table = + cpufreq_frequency_get_table(cpu); + + if (!output) + return -EINVAL; + + if (!table) + return -EINVAL; + + cpufreq_for_each_valid_entry(pos, table) { + /* ignore duplicate entry */ + if (freq == pos->frequency) + continue; + + /* get the frequency order */ + if (freq != CPUFREQ_ENTRY_INVALID && descend == -1) + descend = freq > pos->frequency; + + freq = pos->frequency; + max_level++; + } + + /* No valid cpu frequency entry */ + if (max_level == 0) + return -EINVAL; + + /* max_level is an index, not a counter */ + max_level--; + + /* get max level */ + if (property == GET_MAXL) { + *output = (unsigned int)max_level; + return 0; + } + + if (property == GET_FREQ) + level = descend ? input : (max_level - input); + + i = 0; + cpufreq_for_each_valid_entry(pos, table) { + /* ignore duplicate entry */ + if (freq == pos->frequency) + continue; + + /* now we have a valid frequency entry */ + freq = pos->frequency; + + if (property == GET_LEVEL && (unsigned int)input == freq) { + /* get level by frequency */ + *output = descend ? i : (max_level - i); + return 0; + } + if (property == GET_FREQ && level == i) { + /* get frequency by level */ + *output = freq; + return 0; + } + i++; + } + + return -EINVAL; +} + +/** + * cpufreq_cooling_get_level - for a give 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) +{ + unsigned int val; + + if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL)) + return THERMAL_CSTATE_INVALID; + + return (unsigned long)val; +} +EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level); + +/** + * get_cpu_frequency - get the absolute value of frequency from level. + * @cpu: cpu for which frequency is fetched. + * @level: cooling level + * + * This function matches cooling level with frequency. Based on a cooling level + * of frequency, equals cooling state of cpu cooling device, it will return + * the corresponding frequency. + * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc + * + * Return: 0 on error, the corresponding frequency otherwise. + */ +static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) +{ + int ret = 0; + unsigned int freq; + + ret = get_property(cpu, level, &freq, GET_FREQ); + if (ret) + return 0; + + return freq; +} + +/** + * 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. + * + * Function used to make sure the cpufreq layer is aware of current thermal + * limits. The limits are applied by updating the cpufreq policy. + * + * Return: 0 on success, an error code otherwise (-EINVAL in case wrong + * cooling state). + */ +static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device, + unsigned long cooling_state) +{ + unsigned int cpuid, clip_freq; + struct cpumask *mask = &cpufreq_device->allowed_cpus; + unsigned int cpu = cpumask_any(mask); + + + /* 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, mask) { + 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 + * + * Callback to highjack 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; + + 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; + else + return 0; + + /* 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. + * + * 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; + struct cpumask *mask = &cpufreq_device->allowed_cpus; + unsigned int cpu; + unsigned int count = 0; + int ret; + + cpu = cpumask_any(mask); + + ret = get_property(cpu, 0, &count, GET_MAXL); + + if (count > 0) + *state = count; + + 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. + * + * 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; + + return cpufreq_apply_cooling(cpufreq_device, state); +} + +/* 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 - 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. + * + * 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 = NULL; + unsigned int min = 0, max = 0; + char dev_name[THERMAL_NAME_LENGTH]; + int ret = 0, i; + struct cpufreq_policy policy; + + /* 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); + + ret = get_idr(&cpufreq_idr, &cpufreq_dev->id); + if (ret) { + kfree(cpufreq_dev); + return ERR_PTR(-EINVAL); + } + + 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)) { + release_idr(&cpufreq_idr, cpufreq_dev->id); + kfree(cpufreq_dev); + return cool_dev; + } + cpufreq_dev->cool_dev = cool_dev; + cpufreq_dev->cpufreq_state = 0; + mutex_lock(&cooling_cpufreq_lock); + + /* Register the notifier for first cpufreq cooling device */ + if (cpufreq_dev_count == 0) + cpufreq_register_notifier(&thermal_cpufreq_notifier_block, + CPUFREQ_POLICY_NOTIFIER); + cpufreq_dev_count++; + + mutex_unlock(&cooling_cpufreq_lock); + + 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); + cpufreq_dev_count--; + + /* Unregister the notifier for the last cpufreq cooling device */ + if (cpufreq_dev_count == 0) + 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_GPL(cpufreq_cooling_unregister); |