blob: b276d697390118e54ae0329df9dbb8a5928c91c3 [file] [log] [blame]
/*
* Arch specific cpu topology information
*
* Copyright (C) 2016, ARM Ltd.
* Written by: Juri Lelli, ARM Ltd.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Released under the GPLv2 only.
* SPDX-License-Identifier: GPL-2.0
*/
#include <linux/acpi.h>
#include <linux/arch_topology.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sched/topology.h>
#include <linux/sched/energy.h>
#include <linux/cpuset.h>
DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
DEFINE_PER_CPU(unsigned long, max_cpu_freq);
DEFINE_PER_CPU(unsigned long, max_freq_scale) = SCHED_CAPACITY_SCALE;
void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
unsigned long max_freq)
{
unsigned long scale;
int i;
scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
for_each_cpu(i, cpus) {
per_cpu(freq_scale, i) = scale;
per_cpu(max_cpu_freq, i) = max_freq;
}
}
void arch_set_max_freq_scale(struct cpumask *cpus,
unsigned long policy_max_freq)
{
unsigned long scale, max_freq;
int cpu = cpumask_first(cpus);
if (cpu > nr_cpu_ids)
return;
max_freq = per_cpu(max_cpu_freq, cpu);
if (!max_freq)
return;
scale = (policy_max_freq << SCHED_CAPACITY_SHIFT) / max_freq;
for_each_cpu(cpu, cpus)
per_cpu(max_freq_scale, cpu) = scale;
}
static DEFINE_MUTEX(cpu_scale_mutex);
DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
{
per_cpu(cpu_scale, cpu) = capacity;
}
static ssize_t cpu_capacity_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id));
}
static void update_topology_flags_workfn(struct work_struct *work);
static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);
static ssize_t cpu_capacity_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
int this_cpu = cpu->dev.id;
int i;
unsigned long new_capacity;
ssize_t ret;
cpumask_var_t mask;
if (!count)
return 0;
ret = kstrtoul(buf, 0, &new_capacity);
if (ret)
return ret;
if (new_capacity > SCHED_CAPACITY_SCALE)
return -EINVAL;
mutex_lock(&cpu_scale_mutex);
if (new_capacity < SCHED_CAPACITY_SCALE) {
int highest_score_cpu = 0;
if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
mutex_unlock(&cpu_scale_mutex);
return -ENOMEM;
}
cpumask_andnot(mask, cpu_online_mask,
topology_core_cpumask(this_cpu));
for_each_cpu(i, mask) {
if (topology_get_cpu_scale(NULL, i) ==
SCHED_CAPACITY_SCALE) {
highest_score_cpu = 1;
break;
}
}
free_cpumask_var(mask);
if (!highest_score_cpu) {
mutex_unlock(&cpu_scale_mutex);
return -EINVAL;
}
}
for_each_cpu(i, topology_core_cpumask(this_cpu))
topology_set_cpu_scale(i, new_capacity);
mutex_unlock(&cpu_scale_mutex);
if (topology_detect_flags())
schedule_work(&update_topology_flags_work);
return count;
}
static DEVICE_ATTR_RW(cpu_capacity);
static int register_cpu_capacity_sysctl(void)
{
int i;
struct device *cpu;
for_each_possible_cpu(i) {
cpu = get_cpu_device(i);
if (!cpu) {
pr_err("%s: too early to get CPU%d device!\n",
__func__, i);
continue;
}
device_create_file(cpu, &dev_attr_cpu_capacity);
}
return 0;
}
subsys_initcall(register_cpu_capacity_sysctl);
enum asym_cpucap_type { no_asym, asym_thread, asym_core, asym_die };
static enum asym_cpucap_type asym_cpucap = no_asym;
enum share_cap_type { no_share_cap, share_cap_thread, share_cap_core, share_cap_die};
static enum share_cap_type share_cap = no_share_cap;
#ifdef CONFIG_CPU_FREQ
int detect_share_cap_flag(void)
{
int cpu;
enum share_cap_type share_cap_level = no_share_cap;
struct cpufreq_policy *policy;
for_each_possible_cpu(cpu) {
policy = cpufreq_cpu_get(cpu);
if (!policy)
return 0;
if (share_cap_level < share_cap_thread &&
cpumask_equal(topology_sibling_cpumask(cpu),
policy->related_cpus)) {
share_cap_level = share_cap_thread;
continue;
}
if (cpumask_equal(topology_core_cpumask(cpu),
policy->related_cpus)) {
share_cap_level = share_cap_core;
continue;
}
if (cpumask_equal(cpu_cpu_mask(cpu),
policy->related_cpus)) {
share_cap_level = share_cap_die;
continue;
}
}
if (share_cap != share_cap_level) {
share_cap = share_cap_level;
return 1;
}
return 0;
}
#else
int detect_share_cap_flag(void) { return 0; }
#endif
/*
* Walk cpu topology to determine sched_domain flags.
*
* SD_ASYM_CPUCAPACITY: Indicates the lowest level that spans all cpu
* capacities found in the system for all cpus, i.e. the flag is set
* at the same level for all systems. The current algorithm implements
* this by looking for higher capacities, which doesn't work for all
* conceivable topology, but don't complicate things until it is
* necessary.
*/
int topology_detect_flags(void)
{
unsigned long max_capacity, capacity;
enum asym_cpucap_type asym_level = no_asym;
int cpu, die_cpu, core, thread, flags_changed = 0;
for_each_possible_cpu(cpu) {
max_capacity = 0;
if (asym_level >= asym_thread)
goto check_core;
for_each_cpu(thread, topology_sibling_cpumask(cpu)) {
capacity = topology_get_cpu_scale(NULL, thread);
if (capacity > max_capacity) {
if (max_capacity != 0)
asym_level = asym_thread;
max_capacity = capacity;
}
}
check_core:
if (asym_level >= asym_core)
goto check_die;
for_each_cpu(core, topology_core_cpumask(cpu)) {
capacity = topology_get_cpu_scale(NULL, core);
if (capacity > max_capacity) {
if (max_capacity != 0)
asym_level = asym_core;
max_capacity = capacity;
}
}
check_die:
for_each_possible_cpu(die_cpu) {
capacity = topology_get_cpu_scale(NULL, die_cpu);
if (capacity > max_capacity) {
if (max_capacity != 0) {
asym_level = asym_die;
goto done;
}
}
}
}
done:
if (asym_cpucap != asym_level) {
asym_cpucap = asym_level;
flags_changed = 1;
pr_debug("topology flag change detected\n");
}
if (detect_share_cap_flag())
flags_changed = 1;
return flags_changed;
}
int topology_smt_flags(void)
{
int flags = 0;
if (asym_cpucap == asym_thread)
flags |= SD_ASYM_CPUCAPACITY;
if (share_cap == share_cap_thread)
flags |= SD_SHARE_CAP_STATES;
return flags;
}
int topology_core_flags(void)
{
int flags = 0;
if (asym_cpucap == asym_core)
flags |= SD_ASYM_CPUCAPACITY;
if (share_cap == share_cap_core)
flags |= SD_SHARE_CAP_STATES;
return flags;
}
int topology_cpu_flags(void)
{
int flags = 0;
if (asym_cpucap == asym_die)
flags |= SD_ASYM_CPUCAPACITY;
if (share_cap == share_cap_die)
flags |= SD_SHARE_CAP_STATES;
return flags;
}
static int update_topology = 0;
int topology_update_cpu_topology(void)
{
return update_topology;
}
/*
* Updating the sched_domains can't be done directly from cpufreq callbacks
* due to locking, so queue the work for later.
*/
static void update_topology_flags_workfn(struct work_struct *work)
{
update_topology = 1;
rebuild_sched_domains();
pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
update_topology = 0;
}
static u32 capacity_scale;
static u32 *raw_capacity;
static int free_raw_capacity(void)
{
kfree(raw_capacity);
raw_capacity = NULL;
return 0;
}
void topology_normalize_cpu_scale(void)
{
u64 capacity;
int cpu;
if (!raw_capacity)
return;
pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
mutex_lock(&cpu_scale_mutex);
for_each_possible_cpu(cpu) {
capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
/ capacity_scale;
topology_set_cpu_scale(cpu, capacity);
pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu raw_capacity=%u\n",
cpu, topology_get_cpu_scale(NULL, cpu),
raw_capacity[cpu]);
}
mutex_unlock(&cpu_scale_mutex);
}
bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
{
static bool cap_parsing_failed;
int ret;
u32 cpu_capacity;
if (cap_parsing_failed)
return false;
ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
&cpu_capacity);
if (!ret) {
if (!raw_capacity) {
raw_capacity = kcalloc(num_possible_cpus(),
sizeof(*raw_capacity),
GFP_KERNEL);
if (!raw_capacity) {
pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
cap_parsing_failed = true;
return false;
}
}
capacity_scale = max(cpu_capacity, capacity_scale);
raw_capacity[cpu] = cpu_capacity;
pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
cpu_node, raw_capacity[cpu]);
} else {
if (raw_capacity) {
pr_err("cpu_capacity: missing %pOF raw capacity\n",
cpu_node);
pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
}
cap_parsing_failed = true;
free_raw_capacity();
}
return !ret;
}
#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static void parsing_done_workfn(struct work_struct *work);
static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
static int
init_cpu_capacity_callback(struct notifier_block *nb,
unsigned long val,
void *data)
{
struct cpufreq_policy *policy = data;
int cpu;
if (!raw_capacity)
return 0;
if (val != CPUFREQ_NOTIFY)
return 0;
pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
cpumask_pr_args(policy->related_cpus),
cpumask_pr_args(cpus_to_visit));
cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
for_each_cpu(cpu, policy->related_cpus) {
raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
policy->cpuinfo.max_freq / 1000UL;
capacity_scale = max(raw_capacity[cpu], capacity_scale);
}
if (cpumask_empty(cpus_to_visit)) {
topology_normalize_cpu_scale();
init_sched_energy_costs();
if (topology_detect_flags())
schedule_work(&update_topology_flags_work);
free_raw_capacity();
pr_debug("cpu_capacity: parsing done\n");
schedule_work(&parsing_done_work);
}
return 0;
}
static struct notifier_block init_cpu_capacity_notifier = {
.notifier_call = init_cpu_capacity_callback,
};
static int __init register_cpufreq_notifier(void)
{
int ret;
/*
* on ACPI-based systems we need to use the default cpu capacity
* until we have the necessary code to parse the cpu capacity, so
* skip registering cpufreq notifier.
*/
if (!acpi_disabled || !raw_capacity)
return -EINVAL;
if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
return -ENOMEM;
}
cpumask_copy(cpus_to_visit, cpu_possible_mask);
ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
CPUFREQ_POLICY_NOTIFIER);
if (ret)
free_cpumask_var(cpus_to_visit);
return ret;
}
core_initcall(register_cpufreq_notifier);
static void parsing_done_workfn(struct work_struct *work)
{
cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
CPUFREQ_POLICY_NOTIFIER);
free_cpumask_var(cpus_to_visit);
}
#else
core_initcall(free_raw_capacity);
#endif