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linux-next/drivers/thermal/cpu_cooling.c
Daniel Lezcano 3c74cbb8d0 thermal/drivers/cpu_cooling: Remove pointless test in power2state()
When the static power computation was removed, the test with the power
being negative was not removed. However, the substraction which was
responsible of the negative value was removed and the variable is now
an u32. A double reason to remove the test which does not make sense.

Fixes: 84fe2cab48 ("cpu_cooling: Drop static-power related stuff")
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2019-05-14 07:00:33 -07:00

819 lines
24 KiB
C

/*
* 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 = 1; i <= cpufreq_cdev->max_level; i++)
if (power > freq_table[i].power)
break;
return freq_table[i - 1].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 (trace_thermal_power_cpu_limit_enabled() && 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 target_freq;
u32 last_load, normalised_power;
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
struct cpufreq_policy *policy = cpufreq_cdev->policy;
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 failed to register 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);