/* * 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 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. */ 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) { struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; struct cpumask *maskPtr = &cpufreq_device->allowed_cpus; unsigned int cpu; struct cpufreq_frequency_table *table; unsigned long count = 0; int i = 0; cpu = cpumask_any(maskPtr); table = cpufreq_frequency_get_table(cpu); if (!table) { *state = 0; return 0; } for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) { if (table[i].frequency == CPUFREQ_ENTRY_INVALID) continue; count++; } if (count > 0) { *state = --count; return 0; } return -EINVAL; } /** * 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) { 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. */ 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. */ 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); } 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); /* 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(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 = 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(cpufreq_cooling_unregister);