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Diffstat (limited to '')
| -rw-r--r-- | drivers/thermal/cpu_cooling.c | 820 |
1 files changed, 820 insertions, 0 deletions
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c new file mode 100644 index 000000000..8592ef694 --- /dev/null +++ b/drivers/thermal/cpu_cooling.c @@ -0,0 +1,820 @@ +/* + * 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> + * + * Copyright (C) 2014 Viresh Kumar <viresh.kumar@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/idr.h> +#include <linux/pm_opp.h> +#include <linux/slab.h> +#include <linux/cpu.h> +#include <linux/cpu_cooling.h> + +#include <trace/events/thermal.h> + +/* + * 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 freq_table - frequency table along with power entries + * @frequency: frequency in KHz + * @power: power in mW + * + * This structure is built when the cooling device registers and helps + * in translating frequency to power and vice versa. + */ +struct freq_table { + u32 frequency; + u32 power; +}; + +/** + * struct time_in_idle - Idle time stats + * @time: previous reading of the absolute time that this cpu was idle + * @timestamp: wall time of the last invocation of get_cpu_idle_time_us() + */ +struct time_in_idle { + u64 time; + u64 timestamp; +}; + +/** + * struct cpufreq_cooling_device - data for cooling device with cpufreq + * @id: unique integer value corresponding to each cpufreq_cooling_device + * registered. + * @last_load: load measured by the latest call to cpufreq_get_requested_power() + * @cpufreq_state: integer value representing the current state of cpufreq + * cooling devices. + * @clipped_freq: integer value representing the absolute value of the clipped + * frequency. + * @max_level: maximum cooling level. One less than total number of valid + * cpufreq frequencies. + * @freq_table: Freq table in descending order of frequencies + * @cdev: thermal_cooling_device pointer to keep track of the + * registered cooling device. + * @policy: cpufreq policy. + * @node: list_head to link all cpufreq_cooling_device together. + * @idle_time: idle time stats + * + * This structure is required for keeping information of each registered + * cpufreq_cooling_device. + */ +struct cpufreq_cooling_device { + int id; + u32 last_load; + unsigned int cpufreq_state; + unsigned int clipped_freq; + unsigned int max_level; + struct freq_table *freq_table; /* In descending order */ + struct thermal_cooling_device *cdev; + struct cpufreq_policy *policy; + struct list_head node; + struct time_in_idle *idle_time; +}; + +static DEFINE_IDA(cpufreq_ida); +static DEFINE_MUTEX(cooling_list_lock); +static LIST_HEAD(cpufreq_cdev_list); + +/* Below code defines functions to be used for cpufreq as cooling device */ + +/** + * get_level: Find the level for a particular frequency + * @cpufreq_cdev: cpufreq_cdev for which the property is required + * @freq: Frequency + * + * Return: level corresponding to the frequency. + */ +static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_cdev, + unsigned int freq) +{ + struct freq_table *freq_table = cpufreq_cdev->freq_table; + unsigned long level; + + for (level = 1; level <= cpufreq_cdev->max_level; level++) + if (freq > freq_table[level].frequency) + break; + + return level - 1; +} + +/** + * 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 clipped_freq; + struct cpufreq_cooling_device *cpufreq_cdev; + + if (event != CPUFREQ_ADJUST) + return NOTIFY_DONE; + + mutex_lock(&cooling_list_lock); + list_for_each_entry(cpufreq_cdev, &cpufreq_cdev_list, node) { + /* + * A new copy of the policy is sent to the notifier and can't + * compare that directly. + */ + if (policy->cpu != cpufreq_cdev->policy->cpu) + continue; + + /* + * policy->max is the maximum allowed frequency defined by user + * and clipped_freq is the maximum that thermal constraints + * allow. + * + * If clipped_freq is lower than policy->max, then we need to + * readjust policy->max. + * + * But, if clipped_freq is greater than policy->max, we don't + * need to do anything. + */ + clipped_freq = cpufreq_cdev->clipped_freq; + + if (policy->max > clipped_freq) + cpufreq_verify_within_limits(policy, 0, clipped_freq); + break; + } + mutex_unlock(&cooling_list_lock); + + return NOTIFY_OK; +} + +/** + * update_freq_table() - Update the freq table with power numbers + * @cpufreq_cdev: the cpufreq cooling device in which to update the table + * @capacitance: dynamic power coefficient for these cpus + * + * Update the freq table with power numbers. This table will be used in + * cpu_power_to_freq() and cpu_freq_to_power() to convert between power and + * frequency efficiently. Power is stored in mW, frequency in KHz. The + * resulting table is in descending order. + * + * Return: 0 on success, -EINVAL if there are no OPPs for any CPUs, + * or -ENOMEM if we run out of memory. + */ +static int update_freq_table(struct cpufreq_cooling_device *cpufreq_cdev, + u32 capacitance) +{ + struct freq_table *freq_table = cpufreq_cdev->freq_table; + struct dev_pm_opp *opp; + struct device *dev = NULL; + int num_opps = 0, cpu = cpufreq_cdev->policy->cpu, i; + + dev = get_cpu_device(cpu); + if (unlikely(!dev)) { + dev_warn(&cpufreq_cdev->cdev->device, + "No cpu device for cpu %d\n", cpu); + return -ENODEV; + } + + num_opps = dev_pm_opp_get_opp_count(dev); + if (num_opps < 0) + return num_opps; + + /* + * The cpufreq table is also built from the OPP table and so the count + * should match. + */ + if (num_opps != cpufreq_cdev->max_level + 1) { + dev_warn(dev, "Number of OPPs not matching with max_levels\n"); + return -EINVAL; + } + + for (i = 0; i <= cpufreq_cdev->max_level; i++) { + unsigned long freq = freq_table[i].frequency * 1000; + u32 freq_mhz = freq_table[i].frequency / 1000; + u64 power; + u32 voltage_mv; + + /* + * Find ceil frequency as 'freq' may be slightly lower than OPP + * freq due to truncation while converting to kHz. + */ + opp = dev_pm_opp_find_freq_ceil(dev, &freq); + if (IS_ERR(opp)) { + dev_err(dev, "failed to get opp for %lu frequency\n", + freq); + return -EINVAL; + } + + voltage_mv = dev_pm_opp_get_voltage(opp) / 1000; + dev_pm_opp_put(opp); + + /* + * Do the multiplication with MHz and millivolt so as + * to not overflow. + */ + power = (u64)capacitance * freq_mhz * voltage_mv * voltage_mv; + do_div(power, 1000000000); + + /* power is stored in mW */ + freq_table[i].power = power; + } + + return 0; +} + +static u32 cpu_freq_to_power(struct cpufreq_cooling_device *cpufreq_cdev, + u32 freq) +{ + int i; + struct freq_table *freq_table = cpufreq_cdev->freq_table; + + for (i = 1; i <= cpufreq_cdev->max_level; i++) + if (freq > freq_table[i].frequency) + break; + + return freq_table[i - 1].power; +} + +static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev, + u32 power) +{ + int i; + struct freq_table *freq_table = cpufreq_cdev->freq_table; + + for (i = 0; i < cpufreq_cdev->max_level; i++) + if (power >= freq_table[i].power) + break; + + return freq_table[i].frequency; +} + +/** + * get_load() - get load for a cpu since last updated + * @cpufreq_cdev: &struct cpufreq_cooling_device for this cpu + * @cpu: cpu number + * @cpu_idx: index of the cpu in time_in_idle* + * + * Return: The average load of cpu @cpu in percentage since this + * function was last called. + */ +static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu, + int cpu_idx) +{ + u32 load; + u64 now, now_idle, delta_time, delta_idle; + struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx]; + + now_idle = get_cpu_idle_time(cpu, &now, 0); + delta_idle = now_idle - idle_time->time; + delta_time = now - idle_time->timestamp; + + if (delta_time <= delta_idle) + load = 0; + else + load = div64_u64(100 * (delta_time - delta_idle), delta_time); + + idle_time->time = now_idle; + idle_time->timestamp = now; + + return load; +} + +/** + * get_dynamic_power() - calculate the dynamic power + * @cpufreq_cdev: &cpufreq_cooling_device for this cdev + * @freq: current frequency + * + * Return: the dynamic power consumed by the cpus described by + * @cpufreq_cdev. + */ +static u32 get_dynamic_power(struct cpufreq_cooling_device *cpufreq_cdev, + unsigned long freq) +{ + u32 raw_cpu_power; + + raw_cpu_power = cpu_freq_to_power(cpufreq_cdev, freq); + return (raw_cpu_power * cpufreq_cdev->last_load) / 100; +} + +/* 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_cdev = cdev->devdata; + + *state = cpufreq_cdev->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_cdev = cdev->devdata; + + *state = cpufreq_cdev->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_cdev = cdev->devdata; + unsigned int clip_freq; + + /* Request state should be less than max_level */ + if (WARN_ON(state > cpufreq_cdev->max_level)) + return -EINVAL; + + /* Check if the old cooling action is same as new cooling action */ + if (cpufreq_cdev->cpufreq_state == state) + return 0; + + clip_freq = cpufreq_cdev->freq_table[state].frequency; + cpufreq_cdev->cpufreq_state = state; + cpufreq_cdev->clipped_freq = clip_freq; + + cpufreq_update_policy(cpufreq_cdev->policy->cpu); + + return 0; +} + +/** + * cpufreq_get_requested_power() - get the current power + * @cdev: &thermal_cooling_device pointer + * @tz: a valid thermal zone device pointer + * @power: pointer in which to store the resulting power + * + * Calculate the current power consumption of the cpus in milliwatts + * and store it in @power. This function should actually calculate + * the requested power, but it's hard to get the frequency that + * cpufreq would have assigned if there were no thermal limits. + * Instead, we calculate the current power on the assumption that the + * immediate future will look like the immediate past. + * + * We use the current frequency and the average load since this + * function was last called. In reality, there could have been + * multiple opps since this function was last called and that affects + * the load calculation. While it's not perfectly accurate, this + * simplification is good enough and works. REVISIT this, as more + * complex code may be needed if experiments show that it's not + * accurate enough. + * + * Return: 0 on success, -E* if getting the static power failed. + */ +static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev, + struct thermal_zone_device *tz, + u32 *power) +{ + unsigned long freq; + int i = 0, cpu; + u32 total_load = 0; + struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; + struct cpufreq_policy *policy = cpufreq_cdev->policy; + u32 *load_cpu = NULL; + + freq = cpufreq_quick_get(policy->cpu); + + if (trace_thermal_power_cpu_get_power_enabled()) { + u32 ncpus = cpumask_weight(policy->related_cpus); + + load_cpu = kcalloc(ncpus, sizeof(*load_cpu), GFP_KERNEL); + } + + for_each_cpu(cpu, policy->related_cpus) { + u32 load; + + if (cpu_online(cpu)) + load = get_load(cpufreq_cdev, cpu, i); + else + load = 0; + + total_load += load; + if (load_cpu) + load_cpu[i] = load; + + i++; + } + + cpufreq_cdev->last_load = total_load; + + *power = get_dynamic_power(cpufreq_cdev, freq); + + if (load_cpu) { + trace_thermal_power_cpu_get_power(policy->related_cpus, freq, + load_cpu, i, *power); + + kfree(load_cpu); + } + + return 0; +} + +/** + * cpufreq_state2power() - convert a cpu cdev state to power consumed + * @cdev: &thermal_cooling_device pointer + * @tz: a valid thermal zone device pointer + * @state: cooling device state to be converted + * @power: pointer in which to store the resulting power + * + * Convert cooling device state @state into power consumption in + * milliwatts assuming 100% load. Store the calculated power in + * @power. + * + * Return: 0 on success, -EINVAL if the cooling device state could not + * be converted into a frequency or other -E* if there was an error + * when calculating the static power. + */ +static int cpufreq_state2power(struct thermal_cooling_device *cdev, + struct thermal_zone_device *tz, + unsigned long state, u32 *power) +{ + unsigned int freq, num_cpus; + struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; + + /* Request state should be less than max_level */ + if (WARN_ON(state > cpufreq_cdev->max_level)) + return -EINVAL; + + num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus); + + freq = cpufreq_cdev->freq_table[state].frequency; + *power = cpu_freq_to_power(cpufreq_cdev, freq) * num_cpus; + + return 0; +} + +/** + * cpufreq_power2state() - convert power to a cooling device state + * @cdev: &thermal_cooling_device pointer + * @tz: a valid thermal zone device pointer + * @power: power in milliwatts to be converted + * @state: pointer in which to store the resulting state + * + * Calculate a cooling device state for the cpus described by @cdev + * that would allow them to consume at most @power mW and store it in + * @state. Note that this calculation depends on external factors + * such as the cpu load or the current static power. Calling this + * function with the same power as input can yield different cooling + * device states depending on those external factors. + * + * Return: 0 on success, -ENODEV if no cpus are online or -EINVAL if + * the calculated frequency could not be converted to a valid state. + * The latter should not happen unless the frequencies available to + * cpufreq have changed since the initialization of the cpu cooling + * device. + */ +static int cpufreq_power2state(struct thermal_cooling_device *cdev, + struct thermal_zone_device *tz, u32 power, + unsigned long *state) +{ + unsigned int cur_freq, target_freq; + u32 last_load, normalised_power; + struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; + struct cpufreq_policy *policy = cpufreq_cdev->policy; + + cur_freq = cpufreq_quick_get(policy->cpu); + power = power > 0 ? power : 0; + last_load = cpufreq_cdev->last_load ?: 1; + normalised_power = (power * 100) / last_load; + target_freq = cpu_power_to_freq(cpufreq_cdev, normalised_power); + + *state = get_level(cpufreq_cdev, target_freq); + trace_thermal_power_cpu_limit(policy->related_cpus, target_freq, *state, + power); + return 0; +} + +/* Bind cpufreq callbacks to thermal cooling device ops */ + +static struct thermal_cooling_device_ops cpufreq_cooling_ops = { + .get_max_state = cpufreq_get_max_state, + .get_cur_state = cpufreq_get_cur_state, + .set_cur_state = cpufreq_set_cur_state, +}; + +static struct thermal_cooling_device_ops cpufreq_power_cooling_ops = { + .get_max_state = cpufreq_get_max_state, + .get_cur_state = cpufreq_get_cur_state, + .set_cur_state = cpufreq_set_cur_state, + .get_requested_power = cpufreq_get_requested_power, + .state2power = cpufreq_state2power, + .power2state = cpufreq_power2state, +}; + +/* 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 + * @policy: cpufreq policy + * Normally this should be same as cpufreq policy->related_cpus. + * @capacitance: dynamic power coefficient for these 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, + struct cpufreq_policy *policy, u32 capacitance) +{ + struct thermal_cooling_device *cdev; + struct cpufreq_cooling_device *cpufreq_cdev; + char dev_name[THERMAL_NAME_LENGTH]; + unsigned int freq, i, num_cpus; + int ret; + struct thermal_cooling_device_ops *cooling_ops; + bool first; + + if (IS_ERR_OR_NULL(policy)) { + pr_err("%s: cpufreq policy isn't valid: %p\n", __func__, policy); + return ERR_PTR(-EINVAL); + } + + i = cpufreq_table_count_valid_entries(policy); + if (!i) { + pr_debug("%s: CPUFreq table not found or has no valid entries\n", + __func__); + return ERR_PTR(-ENODEV); + } + + cpufreq_cdev = kzalloc(sizeof(*cpufreq_cdev), GFP_KERNEL); + if (!cpufreq_cdev) + return ERR_PTR(-ENOMEM); + + cpufreq_cdev->policy = policy; + num_cpus = cpumask_weight(policy->related_cpus); + cpufreq_cdev->idle_time = kcalloc(num_cpus, + sizeof(*cpufreq_cdev->idle_time), + GFP_KERNEL); + if (!cpufreq_cdev->idle_time) { + cdev = ERR_PTR(-ENOMEM); + goto free_cdev; + } + + /* max_level is an index, not a counter */ + cpufreq_cdev->max_level = i - 1; + + cpufreq_cdev->freq_table = kmalloc_array(i, + sizeof(*cpufreq_cdev->freq_table), + GFP_KERNEL); + if (!cpufreq_cdev->freq_table) { + cdev = ERR_PTR(-ENOMEM); + goto free_idle_time; + } + + ret = ida_simple_get(&cpufreq_ida, 0, 0, GFP_KERNEL); + if (ret < 0) { + cdev = ERR_PTR(ret); + goto free_table; + } + cpufreq_cdev->id = ret; + + snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d", + cpufreq_cdev->id); + + /* Fill freq-table in descending order of frequencies */ + for (i = 0, freq = -1; i <= cpufreq_cdev->max_level; i++) { + freq = find_next_max(policy->freq_table, freq); + cpufreq_cdev->freq_table[i].frequency = 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); + } + + if (capacitance) { + ret = update_freq_table(cpufreq_cdev, capacitance); + if (ret) { + cdev = ERR_PTR(ret); + goto remove_ida; + } + + cooling_ops = &cpufreq_power_cooling_ops; + } else { + cooling_ops = &cpufreq_cooling_ops; + } + + cdev = thermal_of_cooling_device_register(np, dev_name, cpufreq_cdev, + cooling_ops); + if (IS_ERR(cdev)) + goto remove_ida; + + cpufreq_cdev->clipped_freq = cpufreq_cdev->freq_table[0].frequency; + cpufreq_cdev->cdev = cdev; + + mutex_lock(&cooling_list_lock); + /* Register the notifier for first cpufreq cooling device */ + first = list_empty(&cpufreq_cdev_list); + list_add(&cpufreq_cdev->node, &cpufreq_cdev_list); + mutex_unlock(&cooling_list_lock); + + if (first) + cpufreq_register_notifier(&thermal_cpufreq_notifier_block, + CPUFREQ_POLICY_NOTIFIER); + + return cdev; + +remove_ida: + ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id); +free_table: + kfree(cpufreq_cdev->freq_table); +free_idle_time: + kfree(cpufreq_cdev->idle_time); +free_cdev: + kfree(cpufreq_cdev); + return cdev; +} + +/** + * cpufreq_cooling_register - function to create cpufreq cooling device. + * @policy: cpufreq policy + * + * 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(struct cpufreq_policy *policy) +{ + return __cpufreq_cooling_register(NULL, policy, 0); +} +EXPORT_SYMBOL_GPL(cpufreq_cooling_register); + +/** + * of_cpufreq_cooling_register - function to create cpufreq cooling device. + * @policy: cpufreq policy + * + * 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. + * + * Using this function, the cooling device will implement the power + * extensions by using a simple cpu power model. The cpus must have + * registered their OPPs using the OPP library. + * + * It also takes into account, if property present in policy CPU node, the + * static power consumed by the cpu. + * + * Return: a valid struct thermal_cooling_device pointer on success, + * and NULL on failure. + */ +struct thermal_cooling_device * +of_cpufreq_cooling_register(struct cpufreq_policy *policy) +{ + struct device_node *np = of_get_cpu_node(policy->cpu, NULL); + struct thermal_cooling_device *cdev = NULL; + u32 capacitance = 0; + + if (!np) { + pr_err("cpu_cooling: OF node not available for cpu%d\n", + policy->cpu); + return NULL; + } + + if (of_find_property(np, "#cooling-cells", NULL)) { + of_property_read_u32(np, "dynamic-power-coefficient", + &capacitance); + + cdev = __cpufreq_cooling_register(np, policy, capacitance); + if (IS_ERR(cdev)) { + pr_err("cpu_cooling: cpu%d is not running as cooling device: %ld\n", + policy->cpu, PTR_ERR(cdev)); + cdev = NULL; + } + } + + of_node_put(np); + return cdev; +} +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_cdev; + bool last; + + if (!cdev) + return; + + cpufreq_cdev = cdev->devdata; + + mutex_lock(&cooling_list_lock); + list_del(&cpufreq_cdev->node); + /* Unregister the notifier for the last cpufreq cooling device */ + last = list_empty(&cpufreq_cdev_list); + mutex_unlock(&cooling_list_lock); + + if (last) + cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, + CPUFREQ_POLICY_NOTIFIER); + + thermal_cooling_device_unregister(cpufreq_cdev->cdev); + ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id); + kfree(cpufreq_cdev->idle_time); + kfree(cpufreq_cdev->freq_table); + kfree(cpufreq_cdev); +} +EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister); |