Orange Pi5 kernel

 // SPDX-License-Identifier: GPL-2.0
/*
 * Energy Model of devices
 *
 * Copyright (c) 2018-2020, Arm ltd.
 * Written by: Quentin Perret, Arm ltd.
 * Improvements provided by: Lukasz Luba, Arm ltd.
 */
 
#define pr_fmt(fmt) "energy_model: " fmt
 
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/debugfs.h>
#include <linux/energy_model.h>
#include <linux/sched/topology.h>
#include <linux/slab.h>
 
/*
 * Mutex serializing the registrations of performance domains and letting
 * callbacks defined by drivers sleep.
 */
static DEFINE_MUTEX(em_pd_mutex);
 
static bool _is_cpu_device(struct device *dev)
{
<------>return (dev->bus == &cpu_subsys);
}
 
#ifdef CONFIG_DEBUG_FS
static struct dentry *rootdir;
 
static void em_debug_create_ps(struct em_perf_state *ps, struct dentry *pd)
{
<------>struct dentry *d;
<------>char name[24];
 
<------>snprintf(name, sizeof(name), "ps:%lu", ps->frequency);
 
<------>/* Create per-ps directory */
<------>d = debugfs_create_dir(name, pd);
<------>debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
<------>debugfs_create_ulong("power", 0444, d, &ps->power);
<------>debugfs_create_ulong("cost", 0444, d, &ps->cost);
}
 
static int em_debug_cpus_show(struct seq_file *s, void *unused)
{
<------>seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
 
<------>return 0;
}
DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
 
static int em_debug_units_show(struct seq_file *s, void *unused)
{
<------>struct em_perf_domain *pd = s->private;
<------>char *units = pd->milliwatts ? "milliWatts" : "bogoWatts";
 
<------>seq_printf(s, "%s\n", units);
 
<------>return 0;
}
DEFINE_SHOW_ATTRIBUTE(em_debug_units);
 
static void em_debug_create_pd(struct device *dev)
{
<------>struct dentry *d;
<------>int i;
 
<------>/* Create the directory of the performance domain */
<------>d = debugfs_create_dir(dev_name(dev), rootdir);
 
<------>if (_is_cpu_device(dev))
<------><------>debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
<------><------><------><------>    &em_debug_cpus_fops);
 
<------>debugfs_create_file("units", 0444, d, dev->em_pd, &em_debug_units_fops);
 
<------>/* Create a sub-directory for each performance state */
<------>for (i = 0; i < dev->em_pd->nr_perf_states; i++)
<------><------>em_debug_create_ps(&dev->em_pd->table[i], d);
 
}
 
static void em_debug_remove_pd(struct device *dev)
{
<------>struct dentry *debug_dir;
 
<------>debug_dir = debugfs_lookup(dev_name(dev), rootdir);
<------>debugfs_remove_recursive(debug_dir);
}
 
static int __init em_debug_init(void)
{
<------>/* Create /sys/kernel/debug/energy_model directory */
<------>rootdir = debugfs_create_dir("energy_model", NULL);
 
<------>return 0;
}
fs_initcall(em_debug_init);
#else /* CONFIG_DEBUG_FS */
static void em_debug_create_pd(struct device *dev) {}
static void em_debug_remove_pd(struct device *dev) {}
#endif
 
static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
<------><------><------><------>int nr_states, struct em_data_callback *cb)
{
<------>unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
<------>struct em_perf_state *table;
<------>int i, ret;
<------>u64 fmax;
 
<------>table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
<------>if (!table)
<------><------>return -ENOMEM;
 
<------>/* Build the list of performance states for this performance domain */
<------>for (i = 0, freq = 0; i < nr_states; i++, freq++) {
<------><------>/*
<------><------> * active_power() is a driver callback which ceils 'freq' to
<------><------> * lowest performance state of 'dev' above 'freq' and updates
<------><------> * 'power' and 'freq' accordingly.
<------><------> */
<------><------>ret = cb->active_power(&power, &freq, dev);
<------><------>if (ret) {
<------><------><------>dev_err(dev, "EM: invalid perf. state: %d\n",
<------><------><------><------>ret);
<------><------><------>goto free_ps_table;
<------><------>}
 
<------><------>/*
<------><------> * We expect the driver callback to increase the frequency for
<------><------> * higher performance states.
<------><------> */
<------><------>if (freq <= prev_freq) {
<------><------><------>dev_err(dev, "EM: non-increasing freq: %lu\n",
<------><------><------><------>freq);
<------><------><------>goto free_ps_table;
<------><------>}
 
<------><------>/*
<------><------> * The power returned by active_state() is expected to be
<------><------> * positive, in milli-watts and to fit into 16 bits.
<------><------> */
<------><------>if (!power || power > EM_MAX_POWER) {
<------><------><------>dev_err(dev, "EM: invalid power: %lu\n",
<------><------><------><------>power);
<------><------><------>goto free_ps_table;
<------><------>}
 
<------><------>table[i].power = power;
<------><------>table[i].frequency = prev_freq = freq;
<------>}
 
<------>/* Compute the cost of each performance state. */
<------>fmax = (u64) table[nr_states - 1].frequency;
<------>for (i = nr_states - 1; i >= 0; i--) {
<------><------>unsigned long power_res = em_scale_power(table[i].power);
 
<------><------>table[i].cost = div64_u64(fmax * power_res,
<------><------><------><------><------>  table[i].frequency);
<------><------>if (table[i].cost >= prev_cost) {
<------><------><------>dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
<------><------><------><------>table[i].frequency);
<------><------>} else {
<------><------><------>prev_cost = table[i].cost;
<------><------>}
<------>}
 
<------>pd->table = table;
<------>pd->nr_perf_states = nr_states;
 
<------>return 0;
 
free_ps_table:
<------>kfree(table);
<------>return -EINVAL;
}
 
static int em_create_pd(struct device *dev, int nr_states,
<------><------><------>struct em_data_callback *cb, cpumask_t *cpus)
{
<------>struct em_perf_domain *pd;
<------>struct device *cpu_dev;
<------>int cpu, ret;
 
<------>if (_is_cpu_device(dev)) {
<------><------>pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
<------><------>if (!pd)
<------><------><------>return -ENOMEM;
 
<------><------>cpumask_copy(em_span_cpus(pd), cpus);
<------>} else {
<------><------>pd = kzalloc(sizeof(*pd), GFP_KERNEL);
<------><------>if (!pd)
<------><------><------>return -ENOMEM;
<------>}
 
<------>ret = em_create_perf_table(dev, pd, nr_states, cb);
<------>if (ret) {
<------><------>kfree(pd);
<------><------>return ret;
<------>}
 
<------>if (_is_cpu_device(dev))
<------><------>for_each_cpu(cpu, cpus) {
<------><------><------>cpu_dev = get_cpu_device(cpu);
<------><------><------>cpu_dev->em_pd = pd;
<------><------>}
 
<------>dev->em_pd = pd;
 
<------>return 0;
}
 
/**
 * em_pd_get() - Return the performance domain for a device
 * @dev : Device to find the performance domain for
 *
 * Returns the performance domain to which @dev belongs, or NULL if it doesn't
 * exist.
 */
struct em_perf_domain *em_pd_get(struct device *dev)
{
<------>if (IS_ERR_OR_NULL(dev))
<------><------>return NULL;
 
<------>return dev->em_pd;
}
EXPORT_SYMBOL_GPL(em_pd_get);
 
/**
 * em_cpu_get() - Return the performance domain for a CPU
 * @cpu : CPU to find the performance domain for
 *
 * Returns the performance domain to which @cpu belongs, or NULL if it doesn't
 * exist.
 */
struct em_perf_domain *em_cpu_get(int cpu)
{
<------>struct device *cpu_dev;
 
<------>cpu_dev = get_cpu_device(cpu);
<------>if (!cpu_dev)
<------><------>return NULL;
 
<------>return em_pd_get(cpu_dev);
}
EXPORT_SYMBOL_GPL(em_cpu_get);
 
/**
 * em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
 * @dev		: Device for which the EM is to register
 * @nr_states	: Number of performance states to register
 * @cb		: Callback functions providing the data of the Energy Model
 * @cpus	: Pointer to cpumask_t, which in case of a CPU device is
 *		obligatory. It can be taken from i.e. 'policy->cpus'. For other
 *		type of devices this should be set to NULL.
 * @milliwatts	: Flag indicating that the power values are in milliWatts or
 *		in some other scale. It must be set properly.
 *
 * Create Energy Model tables for a performance domain using the callbacks
 * defined in cb.
 *
 * The @milliwatts is important to set with correct value. Some kernel
 * sub-systems might rely on this flag and check if all devices in the EM are
 * using the same scale.
 *
 * If multiple clients register the same performance domain, all but the first
 * registration will be ignored.
 *
 * Return 0 on success
 */
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
<------><------><------><------>struct em_data_callback *cb, cpumask_t *cpus,
<------><------><------><------>bool milliwatts)
{
<------>unsigned long cap, prev_cap = 0;
<------>int cpu, ret;
 
<------>if (!dev || !nr_states || !cb)
<------><------>return -EINVAL;
 
<------>/*
<------> * Use a mutex to serialize the registration of performance domains and
<------> * let the driver-defined callback functions sleep.
<------> */
<------>mutex_lock(&em_pd_mutex);
 
<------>if (dev->em_pd) {
<------><------>ret = -EEXIST;
<------><------>goto unlock;
<------>}
 
<------>if (_is_cpu_device(dev)) {
<------><------>if (!cpus) {
<------><------><------>dev_err(dev, "EM: invalid CPU mask\n");
<------><------><------>ret = -EINVAL;
<------><------><------>goto unlock;
<------><------>}
 
<------><------>for_each_cpu(cpu, cpus) {
<------><------><------>if (em_cpu_get(cpu)) {
<------><------><------><------>dev_err(dev, "EM: exists for CPU%d\n", cpu);
<------><------><------><------>ret = -EEXIST;
<------><------><------><------>goto unlock;
<------><------><------>}
<------><------><------>/*
<------><------><------> * All CPUs of a domain must have the same
<------><------><------> * micro-architecture since they all share the same
<------><------><------> * table.
<------><------><------> */
<------><------><------>cap = arch_scale_cpu_capacity(cpu);
<------><------><------>if (prev_cap && prev_cap != cap) {
<------><------><------><------>dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
<------><------><------><------><------>cpumask_pr_args(cpus));
 
<------><------><------><------>ret = -EINVAL;
<------><------><------><------>goto unlock;
<------><------><------>}
<------><------><------>prev_cap = cap;
<------><------>}
<------>}
 
<------>ret = em_create_pd(dev, nr_states, cb, cpus);
<------>if (ret)
<------><------>goto unlock;
 
<------>dev->em_pd->milliwatts = milliwatts;
 
<------>em_debug_create_pd(dev);
<------>dev_info(dev, "EM: created perf domain\n");
 
unlock:
<------>mutex_unlock(&em_pd_mutex);
<------>return ret;
}
EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
 
/**
 * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
 * @dev		: Device for which the EM is registered
 *
 * Unregister the EM for the specified @dev (but not a CPU device).
 */
void em_dev_unregister_perf_domain(struct device *dev)
{
<------>if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
<------><------>return;
 
<------>if (_is_cpu_device(dev))
<------><------>return;
 
<------>/*
<------> * The mutex separates all register/unregister requests and protects
<------> * from potential clean-up/setup issues in the debugfs directories.
<------> * The debugfs directory name is the same as device's name.
<------> */
<------>mutex_lock(&em_pd_mutex);
<------>em_debug_remove_pd(dev);
 
<------>kfree(dev->em_pd->table);
<------>kfree(dev->em_pd);
<------>dev->em_pd = NULL;
<------>mutex_unlock(&em_pd_mutex);
}
EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);

	// SPDX-License-Identifier: GPL-2.0
	/*
	* Energy Model of devices
	*
	* Copyright (c) 2018-2020, Arm ltd.
	* Written by: Quentin Perret, Arm ltd.
	* Improvements provided by: Lukasz Luba, Arm ltd.
	*/

	#define pr_fmt(fmt) "energy_model: " fmt

	#include <linux/cpu.h>
	#include <linux/cpumask.h>
	#include <linux/debugfs.h>
	#include <linux/energy_model.h>
	#include <linux/sched/topology.h>
	#include <linux/slab.h>

	/*
	* Mutex serializing the registrations of performance domains and letting
	* callbacks defined by drivers sleep.
	*/
	static DEFINE_MUTEX(em_pd_mutex);

	static bool _is_cpu_device(struct device *dev)
	{
	<------>return (dev->bus == &cpu_subsys);
	}

	#ifdef CONFIG_DEBUG_FS
	static struct dentry *rootdir;

	static void em_debug_create_ps(struct em_perf_state ps, struct dentry pd)
	{
	<------>struct dentry *d;
	<------>char name[24];

	<------>snprintf(name, sizeof(name), "ps:%lu", ps->frequency);

	<------>/* Create per-ps directory */
	<------>d = debugfs_create_dir(name, pd);
	<------>debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
	<------>debugfs_create_ulong("power", 0444, d, &ps->power);
	<------>debugfs_create_ulong("cost", 0444, d, &ps->cost);
	}

	static int em_debug_cpus_show(struct seq_file s, void unused)
	{
	<------>seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));

	<------>return 0;
	}
	DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);

	static int em_debug_units_show(struct seq_file s, void unused)
	{
	<------>struct em_perf_domain *pd = s->private;
	<------>char *units = pd->milliwatts ? "milliWatts" : "bogoWatts";

	<------>seq_printf(s, "%s\n", units);

	<------>return 0;
	}
	DEFINE_SHOW_ATTRIBUTE(em_debug_units);

	static void em_debug_create_pd(struct device *dev)
	{
	<------>struct dentry *d;
	<------>int i;

	<------>/* Create the directory of the performance domain */
	<------>d = debugfs_create_dir(dev_name(dev), rootdir);

	<------>if (_is_cpu_device(dev))
	<------><------>debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
	<------><------><------><------> &em_debug_cpus_fops);

	<------>debugfs_create_file("units", 0444, d, dev->em_pd, &em_debug_units_fops);

	<------>/* Create a sub-directory for each performance state */
	<------>for (i = 0; i < dev->em_pd->nr_perf_states; i++)
	<------><------>em_debug_create_ps(&dev->em_pd->table[i], d);

	}

	static void em_debug_remove_pd(struct device *dev)
	{
	<------>struct dentry *debug_dir;

	<------>debug_dir = debugfs_lookup(dev_name(dev), rootdir);
	<------>debugfs_remove_recursive(debug_dir);
	}

	static int __init em_debug_init(void)
	{
	<------>/* Create /sys/kernel/debug/energy_model directory */
	<------>rootdir = debugfs_create_dir("energy_model", NULL);

	<------>return 0;
	}
	fs_initcall(em_debug_init);
	#else /* CONFIG_DEBUG_FS */
	static void em_debug_create_pd(struct device *dev) {}
	static void em_debug_remove_pd(struct device *dev) {}
	#endif

	static int em_create_perf_table(struct device dev, struct em_perf_domain pd,
	<------><------><------><------>int nr_states, struct em_data_callback *cb)
	{
	<------>unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
	<------>struct em_perf_state *table;
	<------>int i, ret;
	<------>u64 fmax;

	<------>table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
	<------>if (!table)
	<------><------>return -ENOMEM;

	<------>/* Build the list of performance states for this performance domain */
	<------>for (i = 0, freq = 0; i < nr_states; i++, freq++) {
	<------><------>/*
	<------><------> * active_power() is a driver callback which ceils 'freq' to
	<------><------> * lowest performance state of 'dev' above 'freq' and updates
	<------><------> * 'power' and 'freq' accordingly.
	<------><------> */
	<------><------>ret = cb->active_power(&power, &freq, dev);
	<------><------>if (ret) {
	<------><------><------>dev_err(dev, "EM: invalid perf. state: %d\n",
	<------><------><------><------>ret);
	<------><------><------>goto free_ps_table;
	<------><------>}

	<------><------>/*
	<------><------> * We expect the driver callback to increase the frequency for
	<------><------> * higher performance states.
	<------><------> */
	<------><------>if (freq <= prev_freq) {
	<------><------><------>dev_err(dev, "EM: non-increasing freq: %lu\n",
	<------><------><------><------>freq);
	<------><------><------>goto free_ps_table;
	<------><------>}

	<------><------>/*
	<------><------> * The power returned by active_state() is expected to be
	<------><------> * positive, in milli-watts and to fit into 16 bits.
	<------><------> */
	<------><------>if (!power \|\| power > EM_MAX_POWER) {
	<------><------><------>dev_err(dev, "EM: invalid power: %lu\n",
	<------><------><------><------>power);
	<------><------><------>goto free_ps_table;
	<------><------>}

	<------><------>table[i].power = power;
	<------><------>table[i].frequency = prev_freq = freq;
	<------>}

	<------>/* Compute the cost of each performance state. */
	<------>fmax = (u64) table[nr_states - 1].frequency;
	<------>for (i = nr_states - 1; i >= 0; i--) {
	<------><------>unsigned long power_res = em_scale_power(table[i].power);

	<------><------>table[i].cost = div64_u64(fmax * power_res,
	<------><------><------><------><------> table[i].frequency);
	<------><------>if (table[i].cost >= prev_cost) {
	<------><------><------>dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
	<------><------><------><------>table[i].frequency);
	<------><------>} else {
	<------><------><------>prev_cost = table[i].cost;
	<------><------>}
	<------>}

	<------>pd->table = table;
	<------>pd->nr_perf_states = nr_states;

	<------>return 0;

	free_ps_table:
	<------>kfree(table);
	<------>return -EINVAL;
	}

	static int em_create_pd(struct device *dev, int nr_states,
	<------><------><------>struct em_data_callback cb, cpumask_t cpus)
	{
	<------>struct em_perf_domain *pd;
	<------>struct device *cpu_dev;
	<------>int cpu, ret;

	<------>if (_is_cpu_device(dev)) {
	<------><------>pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
	<------><------>if (!pd)
	<------><------><------>return -ENOMEM;

	<------><------>cpumask_copy(em_span_cpus(pd), cpus);
	<------>} else {
	<------><------>pd = kzalloc(sizeof(*pd), GFP_KERNEL);
	<------><------>if (!pd)
	<------><------><------>return -ENOMEM;
	<------>}

	<------>ret = em_create_perf_table(dev, pd, nr_states, cb);
	<------>if (ret) {
	<------><------>kfree(pd);
	<------><------>return ret;
	<------>}

	<------>if (_is_cpu_device(dev))
	<------><------>for_each_cpu(cpu, cpus) {
	<------><------><------>cpu_dev = get_cpu_device(cpu);
	<------><------><------>cpu_dev->em_pd = pd;
	<------><------>}

	<------>dev->em_pd = pd;

	<------>return 0;
	}

	/**
	* em_pd_get() - Return the performance domain for a device
	* @dev : Device to find the performance domain for
	*
	* Returns the performance domain to which @dev belongs, or NULL if it doesn't
	* exist.
	*/
	struct em_perf_domain em_pd_get(struct device dev)
	{
	<------>if (IS_ERR_OR_NULL(dev))
	<------><------>return NULL;

	<------>return dev->em_pd;
	}
	EXPORT_SYMBOL_GPL(em_pd_get);

	/**
	* em_cpu_get() - Return the performance domain for a CPU
	* @cpu : CPU to find the performance domain for
	*
	* Returns the performance domain to which @cpu belongs, or NULL if it doesn't
	* exist.
	*/
	struct em_perf_domain *em_cpu_get(int cpu)
	{
	<------>struct device *cpu_dev;

	<------>cpu_dev = get_cpu_device(cpu);
	<------>if (!cpu_dev)
	<------><------>return NULL;

	<------>return em_pd_get(cpu_dev);
	}
	EXPORT_SYMBOL_GPL(em_cpu_get);

	/**
	* em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
	* @dev : Device for which the EM is to register
	* @nr_states : Number of performance states to register
	* @cb : Callback functions providing the data of the Energy Model
	* @cpus : Pointer to cpumask_t, which in case of a CPU device is
	* obligatory. It can be taken from i.e. 'policy->cpus'. For other
	* type of devices this should be set to NULL.
	* @milliwatts : Flag indicating that the power values are in milliWatts or
	* in some other scale. It must be set properly.
	*
	* Create Energy Model tables for a performance domain using the callbacks
	* defined in cb.
	*
	* The @milliwatts is important to set with correct value. Some kernel
	* sub-systems might rely on this flag and check if all devices in the EM are
	* using the same scale.
	*
	* If multiple clients register the same performance domain, all but the first
	* registration will be ignored.
	*
	* Return 0 on success
	*/
	int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
	<------><------><------><------>struct em_data_callback cb, cpumask_t cpus,
	<------><------><------><------>bool milliwatts)
	{
	<------>unsigned long cap, prev_cap = 0;
	<------>int cpu, ret;

	<------>if (!dev \|\| !nr_states \|\| !cb)
	<------><------>return -EINVAL;

	<------>/*
	<------> * Use a mutex to serialize the registration of performance domains and
	<------> * let the driver-defined callback functions sleep.
	<------> */
	<------>mutex_lock(&em_pd_mutex);

	<------>if (dev->em_pd) {
	<------><------>ret = -EEXIST;
	<------><------>goto unlock;
	<------>}

	<------>if (_is_cpu_device(dev)) {
	<------><------>if (!cpus) {
	<------><------><------>dev_err(dev, "EM: invalid CPU mask\n");
	<------><------><------>ret = -EINVAL;
	<------><------><------>goto unlock;
	<------><------>}

	<------><------>for_each_cpu(cpu, cpus) {
	<------><------><------>if (em_cpu_get(cpu)) {
	<------><------><------><------>dev_err(dev, "EM: exists for CPU%d\n", cpu);
	<------><------><------><------>ret = -EEXIST;
	<------><------><------><------>goto unlock;
	<------><------><------>}
	<------><------><------>/*
	<------><------><------> * All CPUs of a domain must have the same
	<------><------><------> * micro-architecture since they all share the same
	<------><------><------> * table.
	<------><------><------> */
	<------><------><------>cap = arch_scale_cpu_capacity(cpu);
	<------><------><------>if (prev_cap && prev_cap != cap) {
	<------><------><------><------>dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
	<------><------><------><------><------>cpumask_pr_args(cpus));

	<------><------><------><------>ret = -EINVAL;
	<------><------><------><------>goto unlock;
	<------><------><------>}
	<------><------><------>prev_cap = cap;
	<------><------>}
	<------>}

	<------>ret = em_create_pd(dev, nr_states, cb, cpus);
	<------>if (ret)
	<------><------>goto unlock;

	<------>dev->em_pd->milliwatts = milliwatts;

	<------>em_debug_create_pd(dev);
	<------>dev_info(dev, "EM: created perf domain\n");

	unlock:
	<------>mutex_unlock(&em_pd_mutex);
	<------>return ret;
	}
	EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);

	/**
	* em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
	* @dev : Device for which the EM is registered
	*
	* Unregister the EM for the specified @dev (but not a CPU device).
	*/
	void em_dev_unregister_perf_domain(struct device *dev)
	{
	<------>if (IS_ERR_OR_NULL(dev) \|\| !dev->em_pd)
	<------><------>return;

	<------>if (_is_cpu_device(dev))
	<------><------>return;

	<------>/*
	<------> * The mutex separates all register/unregister requests and protects
	<------> * from potential clean-up/setup issues in the debugfs directories.
	<------> * The debugfs directory name is the same as device's name.
	<------> */
	<------>mutex_lock(&em_pd_mutex);
	<------>em_debug_remove_pd(dev);

	<------>kfree(dev->em_pd->table);
	<------>kfree(dev->em_pd);
	<------>dev->em_pd = NULL;
	<------>mutex_unlock(&em_pd_mutex);
	}
	EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);