/* * linux/drivers/thermal/cpu_cooling.c * * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) * Copyright (C) 2012 Amit Daniel * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * 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 #include #include #include #include #include #include /* * Cooling state <-> CPUFreq frequency * * Cooling states are translated to frequencies throughout this driver and this * is the relation between them. * * Highest cooling state corresponds to lowest possible frequency. * * i.e. * level 0 --> 1st Max Freq * level 1 --> 2nd Max Freq * ... */ /** * 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. * @max_level: maximum cooling level. One less than total number of valid * cpufreq frequencies. * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device. * * This structure is required for keeping information of each registered * cpufreq_cooling_device. */ struct cpufreq_cooling_device { int id; struct thermal_cooling_device *cool_dev; unsigned int cpufreq_state; unsigned int cpufreq_val; unsigned int max_level; unsigned int *freq_table; /* In descending order */ struct cpumask allowed_cpus; struct list_head node; }; static DEFINE_IDR(cpufreq_idr); static DEFINE_MUTEX(cooling_cpufreq_lock); 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 */ /** * get_level: Find the level for a particular frequency * @cpufreq_dev: cpufreq_dev for which the property is required * @freq: Frequency * * Return: level on success, THERMAL_CSTATE_INVALID on error. */ static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_dev, unsigned int freq) { unsigned long level; for (level = 0; level <= cpufreq_dev->max_level; level++) { if (freq == cpufreq_dev->freq_table[level]) return level; if (freq > cpufreq_dev->freq_table[level]) break; } return THERMAL_CSTATE_INVALID; } /** * cpufreq_cooling_get_level - for a given 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) { struct cpufreq_cooling_device *cpufreq_dev; mutex_lock(&cooling_cpufreq_lock); list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) { if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) { mutex_unlock(&cooling_cpufreq_lock); return get_level(cpufreq_dev, freq); } } mutex_unlock(&cooling_cpufreq_lock); pr_err("%s: cpu:%d not part of any cooling device\n", __func__, cpu); return THERMAL_CSTATE_INVALID; } EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level); /** * 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; 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; *state = cpufreq_device->max_level; return 0; } /** * 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; unsigned int cpu = cpumask_any(&cpufreq_device->allowed_cpus); unsigned int clip_freq; /* Request state should be less than max_level */ if (WARN_ON(state > cpufreq_device->max_level)) return -EINVAL; /* Check if the old cooling action is same as new cooling action */ if (cpufreq_device->cpufreq_state == state) return 0; clip_freq = cpufreq_device->freq_table[state]; cpufreq_device->cpufreq_state = state; cpufreq_device->cpufreq_val = clip_freq; cpufreq_update_policy(cpu); return 0; } /* 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, }; static unsigned int find_next_max(struct cpufreq_frequency_table *table, unsigned int prev_max) { struct cpufreq_frequency_table *pos; unsigned int max = 0; cpufreq_for_each_valid_entry(pos, table) { if (pos->frequency > max && pos->frequency < prev_max) max = pos->frequency; } return max; } /** * __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. * Normally this should be same as cpufreq policy->related_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. 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; char dev_name[THERMAL_NAME_LENGTH]; struct cpufreq_frequency_table *pos, *table; unsigned int freq, i; int ret; table = cpufreq_frequency_get_table(cpumask_first(clip_cpus)); if (!table) { pr_debug("%s: CPUFreq table not found\n", __func__); return ERR_PTR(-EPROBE_DEFER); } cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL); if (!cpufreq_dev) return ERR_PTR(-ENOMEM); /* Find max levels */ cpufreq_for_each_valid_entry(pos, table) cpufreq_dev->max_level++; cpufreq_dev->freq_table = kmalloc(sizeof(*cpufreq_dev->freq_table) * cpufreq_dev->max_level, GFP_KERNEL); if (!cpufreq_dev->freq_table) { return ERR_PTR(-ENOMEM); cool_dev = ERR_PTR(-ENOMEM); goto free_cdev; } /* max_level is an index, not a counter */ cpufreq_dev->max_level--; cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus); ret = get_idr(&cpufreq_idr, &cpufreq_dev->id); if (ret) { cool_dev = ERR_PTR(ret); goto free_table; } 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)) goto remove_idr; /* Fill freq-table in descending order of frequencies */ for (i = 0, freq = -1; i <= cpufreq_dev->max_level; i++) { freq = find_next_max(table, freq); cpufreq_dev->freq_table[i] = freq; /* Warn for duplicate entries */ if (!freq) pr_warn("%s: table has duplicate entries\n", __func__); else pr_debug("%s: freq:%u KHz\n", __func__, freq); } cpufreq_dev->cpufreq_val = cpufreq_dev->freq_table[0]; cpufreq_dev->cool_dev = cool_dev; mutex_lock(&cooling_cpufreq_lock); /* Register the notifier for first cpufreq cooling device */ if (list_empty(&cpufreq_dev_list)) cpufreq_register_notifier(&thermal_cpufreq_notifier_block, CPUFREQ_POLICY_NOTIFIER); list_add(&cpufreq_dev->node, &cpufreq_dev_list); mutex_unlock(&cooling_cpufreq_lock); return cool_dev; remove_idr: release_idr(&cpufreq_idr, cpufreq_dev->id); free_table: kfree(cpufreq_dev->freq_table); free_cdev: kfree(cpufreq_dev); 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); /* Unregister the notifier for the last cpufreq cooling device */ if (list_empty(&cpufreq_dev_list)) 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->freq_table); kfree(cpufreq_dev); } EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);