439 lines
10 KiB
C
439 lines
10 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
/*
|
||
|
|
* Energy Model of devices
|
||
|
|
*
|
||
|
|
* Copyright (c) 2018-2021, 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/cpufreq.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);
|
||
|
|
debugfs_create_ulong("inefficient", 0444, d, &ps->flags);
|
||
|
|
}
|
||
|
|
|
||
|
|
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_flags_show(struct seq_file *s, void *unused)
|
||
|
|
{
|
||
|
|
struct em_perf_domain *pd = s->private;
|
||
|
|
|
||
|
|
seq_printf(s, "%#lx\n", pd->flags);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
DEFINE_SHOW_ATTRIBUTE(em_debug_flags);
|
||
|
|
|
||
|
|
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("flags", 0444, d, dev->em_pd,
|
||
|
|
&em_debug_flags_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)
|
||
|
|
{
|
||
|
|
debugfs_lookup_and_remove(dev_name(dev), rootdir);
|
||
|
|
}
|
||
|
|
|
||
|
|
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 flags)
|
||
|
|
{
|
||
|
|
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(dev, &power, &freq);
|
||
|
|
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 and be in range.
|
||
|
|
*/
|
||
|
|
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, cost;
|
||
|
|
|
||
|
|
if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
|
||
|
|
ret = cb->get_cost(dev, table[i].frequency, &cost);
|
||
|
|
if (ret || !cost || cost > EM_MAX_POWER) {
|
||
|
|
dev_err(dev, "EM: invalid cost %lu %d\n",
|
||
|
|
cost, ret);
|
||
|
|
goto free_ps_table;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
power_res = table[i].power;
|
||
|
|
cost = div64_u64(fmax * power_res, table[i].frequency);
|
||
|
|
}
|
||
|
|
|
||
|
|
table[i].cost = cost;
|
||
|
|
|
||
|
|
if (table[i].cost >= prev_cost) {
|
||
|
|
table[i].flags = EM_PERF_STATE_INEFFICIENT;
|
||
|
|
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,
|
||
|
|
unsigned long flags)
|
||
|
|
{
|
||
|
|
struct em_perf_domain *pd;
|
||
|
|
struct device *cpu_dev;
|
||
|
|
int cpu, ret, num_cpus;
|
||
|
|
|
||
|
|
if (_is_cpu_device(dev)) {
|
||
|
|
num_cpus = cpumask_weight(cpus);
|
||
|
|
|
||
|
|
/* Prevent max possible energy calculation to not overflow */
|
||
|
|
if (num_cpus > EM_MAX_NUM_CPUS) {
|
||
|
|
dev_err(dev, "EM: too many CPUs, overflow possible\n");
|
||
|
|
return -EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
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, flags);
|
||
|
|
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;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void em_cpufreq_update_efficiencies(struct device *dev)
|
||
|
|
{
|
||
|
|
struct em_perf_domain *pd = dev->em_pd;
|
||
|
|
struct em_perf_state *table;
|
||
|
|
struct cpufreq_policy *policy;
|
||
|
|
int found = 0;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
if (!_is_cpu_device(dev) || !pd)
|
||
|
|
return;
|
||
|
|
|
||
|
|
policy = cpufreq_cpu_get(cpumask_first(em_span_cpus(pd)));
|
||
|
|
if (!policy) {
|
||
|
|
dev_warn(dev, "EM: Access to CPUFreq policy failed");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
table = pd->table;
|
||
|
|
|
||
|
|
for (i = 0; i < pd->nr_perf_states; i++) {
|
||
|
|
if (!(table[i].flags & EM_PERF_STATE_INEFFICIENT))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
if (!cpufreq_table_set_inefficient(policy, table[i].frequency))
|
||
|
|
found++;
|
||
|
|
}
|
||
|
|
|
||
|
|
cpufreq_cpu_put(policy);
|
||
|
|
|
||
|
|
if (!found)
|
||
|
|
return;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Efficiencies have been installed in CPUFreq, inefficient frequencies
|
||
|
|
* will be skipped. The EM can do the same.
|
||
|
|
*/
|
||
|
|
pd->flags |= EM_PERF_DOMAIN_SKIP_INEFFICIENCIES;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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.
|
||
|
|
* @microwatts : Flag indicating that the power values are in micro-Watts 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 @microwatts 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 microwatts)
|
||
|
|
{
|
||
|
|
unsigned long cap, prev_cap = 0;
|
||
|
|
unsigned long flags = 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;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (microwatts)
|
||
|
|
flags |= EM_PERF_DOMAIN_MICROWATTS;
|
||
|
|
else if (cb->get_cost)
|
||
|
|
flags |= EM_PERF_DOMAIN_ARTIFICIAL;
|
||
|
|
|
||
|
|
ret = em_create_pd(dev, nr_states, cb, cpus, flags);
|
||
|
|
if (ret)
|
||
|
|
goto unlock;
|
||
|
|
|
||
|
|
dev->em_pd->flags |= flags;
|
||
|
|
|
||
|
|
em_cpufreq_update_efficiencies(dev);
|
||
|
|
|
||
|
|
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);
|