| /* |
| * 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, j; |
| unsigned long max_level = 0, level = 0; |
| unsigned int freq = CPUFREQ_ENTRY_INVALID; |
| int descend = -1; |
| struct cpufreq_frequency_table *table = |
| cpufreq_frequency_get_table(cpu); |
| |
| if (!output) |
| return -EINVAL; |
| |
| if (!table) |
| return -EINVAL; |
| |
| for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { |
| /* ignore invalid entries */ |
| if (table[i].frequency == CPUFREQ_ENTRY_INVALID) |
| continue; |
| |
| /* ignore duplicate entry */ |
| if (freq == table[i].frequency) |
| continue; |
| |
| /* get the frequency order */ |
| if (freq != CPUFREQ_ENTRY_INVALID && descend == -1) |
| descend = !!(freq > table[i].frequency); |
| |
| freq = table[i].frequency; |
| 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 - 1); |
| |
| for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { |
| /* ignore invalid entry */ |
| if (table[i].frequency == CPUFREQ_ENTRY_INVALID) |
| continue; |
| |
| /* ignore duplicate entry */ |
| if (freq == table[i].frequency) |
| continue; |
| |
| /* now we have a valid frequency entry */ |
| freq = table[i].frequency; |
| |
| if (property == GET_LEVEL && (unsigned int)input == freq) { |
| /* get level by frequency */ |
| *output = descend ? j : (max_level - j - 1); |
| return 0; |
| } |
| if (property == GET_FREQ && level == j) { |
| /* get frequency by level */ |
| *output = freq; |
| return 0; |
| } |
| j++; |
| } |
| |
| 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 - 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) |
| { |
| 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_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); |
| |
| /* 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; |
| } |
| EXPORT_SYMBOL_GPL(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 = 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); |