/* * 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; struct list_head node; }; static DEFINE_IDR(cpufreq_idr); static DEFINE_MUTEX(cooling_cpufreq_lock); static unsigned int cpufreq_dev_count; static LIST_HEAD(cpufreq_dev_list); /** * 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; for_each_cpu(cpuid, mask) { if (is_cpufreq_valid(cpuid)) cpufreq_update_policy(cpuid); } 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 hijack 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; struct cpufreq_cooling_device *cpufreq_dev; if (event != CPUFREQ_ADJUST) return 0; mutex_lock(&cooling_cpufreq_lock); list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) { if (!cpumask_test_cpu(policy->cpu, &cpufreq_dev->allowed_cpus)) continue; if (!cpufreq_dev->cpufreq_val) cpufreq_dev->cpufreq_val = get_cpu_frequency( cpumask_any(&cpufreq_dev->allowed_cpus), cpufreq_dev->cpufreq_state); max_freq = cpufreq_dev->cpufreq_val; if (policy->max != max_freq) cpufreq_verify_within_limits(policy, 0, max_freq); } mutex_unlock(&cooling_cpufreq_lock); 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++; list_add(&cpufreq_dev->node, &cpufreq_dev_list); 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); list_del(&cpufreq_dev->node); 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);