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android-kvm / linux / 2579af94c813d16bfabd81797f492fdfba25d088 / . / drivers / cpufreq / cpufreq.c
blob: 7e56a42750ea59eb3211856811f35c4b67942280 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/cpufreq/cpufreq.c
*
* Copyright (C) 2001 Russell King
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
* (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
*
* Oct 2005 - Ashok Raj <ashok.raj@intel.com>
* Added handling for CPU hotplug
* Feb 2006 - Jacob Shin <jacob.shin@amd.com>
* Fix handling for CPU hotplug -- affected CPUs
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpu_cooling.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/tick.h>
#include <linux/units.h>
#include <trace/events/power.h>
static LIST_HEAD(cpufreq_policy_list);
/* Macros to iterate over CPU policies */
#define for_each_suitable_policy(__policy, __active) \
list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
if ((__active) == !policy_is_inactive(__policy))
#define for_each_active_policy(__policy) \
for_each_suitable_policy(__policy, true)
#define for_each_inactive_policy(__policy) \
for_each_suitable_policy(__policy, false)
/* Iterate over governors */
static LIST_HEAD(cpufreq_governor_list);
#define for_each_governor(__governor) \
list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
static char default_governor[CPUFREQ_NAME_LEN];
/*
* The "cpufreq driver" - the arch- or hardware-dependent low
* level driver of CPUFreq support, and its spinlock. This lock
* also protects the cpufreq_cpu_data array.
*/
static struct cpufreq_driver *cpufreq_driver;
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
static DEFINE_RWLOCK(cpufreq_driver_lock);
static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
bool cpufreq_supports_freq_invariance(void)
{
return static_branch_likely(&cpufreq_freq_invariance);
}
/* Flag to suspend/resume CPUFreq governors */
static bool cpufreq_suspended;
static inline bool has_target(void)
{
return cpufreq_driver->target_index || cpufreq_driver->target;
}
/* internal prototypes */
static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
static int cpufreq_init_governor(struct cpufreq_policy *policy);
static void cpufreq_exit_governor(struct cpufreq_policy *policy);
static void cpufreq_governor_limits(struct cpufreq_policy *policy);
static int cpufreq_set_policy(struct cpufreq_policy *policy,
struct cpufreq_governor *new_gov,
unsigned int new_pol);
/*
* Two notifier lists: the "policy" list is involved in the
* validation process for a new CPU frequency policy; the
* "transition" list for kernel code that needs to handle
* changes to devices when the CPU clock speed changes.
* The mutex locks both lists.
*/
static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
static int off __read_mostly;
static int cpufreq_disabled(void)
{
return off;
}
void disable_cpufreq(void)
{
off = 1;
}
static DEFINE_MUTEX(cpufreq_governor_mutex);
bool have_governor_per_policy(void)
{
return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
}
EXPORT_SYMBOL_GPL(have_governor_per_policy);
static struct kobject *cpufreq_global_kobject;
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
{
if (have_governor_per_policy())
return &policy->kobj;
else
return cpufreq_global_kobject;
}
EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
struct kernel_cpustat kcpustat;
u64 cur_wall_time;
u64 idle_time;
u64 busy_time;
cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
kcpustat_cpu_fetch(&kcpustat, cpu);
busy_time = kcpustat.cpustat[CPUTIME_USER];
busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
busy_time += kcpustat.cpustat[CPUTIME_IRQ];
busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
busy_time += kcpustat.cpustat[CPUTIME_STEAL];
busy_time += kcpustat.cpustat[CPUTIME_NICE];
idle_time = cur_wall_time - busy_time;
if (wall)
*wall = div_u64(cur_wall_time, NSEC_PER_USEC);
return div_u64(idle_time, NSEC_PER_USEC);
}
u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
{
u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
if (idle_time == -1ULL)
return get_cpu_idle_time_jiffy(cpu, wall);
else if (!io_busy)
idle_time += get_cpu_iowait_time_us(cpu, wall);
return idle_time;
}
EXPORT_SYMBOL_GPL(get_cpu_idle_time);
/*
* This is a generic cpufreq init() routine which can be used by cpufreq
* drivers of SMP systems. It will do following:
* - validate & show freq table passed
* - set policies transition latency
* - policy->cpus with all possible CPUs
*/
void cpufreq_generic_init(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table,
unsigned int transition_latency)
{
policy->freq_table = table;
policy->cpuinfo.transition_latency = transition_latency;
/*
* The driver only supports the SMP configuration where all processors
* share the clock and voltage and clock.
*/
cpumask_setall(policy->cpus);
}
EXPORT_SYMBOL_GPL(cpufreq_generic_init);
struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
{
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
unsigned int cpufreq_generic_get(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
if (!policy || IS_ERR(policy->clk)) {
pr_err("%s: No %s associated to cpu: %d\n",
__func__, policy ? "clk" : "policy", cpu);
return 0;
}
return clk_get_rate(policy->clk) / 1000;
}
EXPORT_SYMBOL_GPL(cpufreq_generic_get);
/**
* cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
* @cpu: CPU to find the policy for.
*
* Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
* the kobject reference counter of that policy. Return a valid policy on
* success or NULL on failure.
*
* The policy returned by this function has to be released with the help of
* cpufreq_cpu_put() to balance its kobject reference counter properly.
*/
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
struct cpufreq_policy *policy = NULL;
unsigned long flags;
if (WARN_ON(cpu >= nr_cpu_ids))
return NULL;
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
/* get the CPU */
policy = cpufreq_cpu_get_raw(cpu);
if (policy)
kobject_get(&policy->kobj);
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
/**
* cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
* @policy: cpufreq policy returned by cpufreq_cpu_get().
*/
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
kobject_put(&policy->kobj);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
/**
* cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
* @policy: cpufreq policy returned by cpufreq_cpu_acquire().
*/
void cpufreq_cpu_release(struct cpufreq_policy *policy)
{
if (WARN_ON(!policy))
return;
lockdep_assert_held(&policy->rwsem);
up_write(&policy->rwsem);
cpufreq_cpu_put(policy);
}
/**
* cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
* @cpu: CPU to find the policy for.
*
* Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
* if the policy returned by it is not NULL, acquire its rwsem for writing.
* Return the policy if it is active or release it and return NULL otherwise.
*
* The policy returned by this function has to be released with the help of
* cpufreq_cpu_release() in order to release its rwsem and balance its usage
* counter properly.
*/
struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
if (!policy)
return NULL;
down_write(&policy->rwsem);
if (policy_is_inactive(policy)) {
cpufreq_cpu_release(policy);
return NULL;
}
return policy;
}
/*********************************************************************
* EXTERNALLY AFFECTING FREQUENCY CHANGES *
*********************************************************************/
/**
* adjust_jiffies - Adjust the system "loops_per_jiffy".
* @val: CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
* @ci: Frequency change information.
*
* This function alters the system "loops_per_jiffy" for the clock
* speed change. Note that loops_per_jiffy cannot be updated on SMP
* systems as each CPU might be scaled differently. So, use the arch
* per-CPU loops_per_jiffy value wherever possible.
*/
static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
{
#ifndef CONFIG_SMP
static unsigned long l_p_j_ref;
static unsigned int l_p_j_ref_freq;
if (ci->flags & CPUFREQ_CONST_LOOPS)
return;
if (!l_p_j_ref_freq) {
l_p_j_ref = loops_per_jiffy;
l_p_j_ref_freq = ci->old;
pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
l_p_j_ref, l_p_j_ref_freq);
}
if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
ci->new);
pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
loops_per_jiffy, ci->new);
}
#endif
}
/**
* cpufreq_notify_transition - Notify frequency transition and adjust jiffies.
* @policy: cpufreq policy to enable fast frequency switching for.
* @freqs: contain details of the frequency update.
* @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
*
* This function calls the transition notifiers and adjust_jiffies().
*
* It is called twice on all CPU frequency changes that have external effects.
*/
static void cpufreq_notify_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs,
unsigned int state)
{
int cpu;
BUG_ON(irqs_disabled());
if (cpufreq_disabled())
return;
freqs->policy = policy;
freqs->flags = cpufreq_driver->flags;
pr_debug("notification %u of frequency transition to %u kHz\n",
state, freqs->new);
switch (state) {
case CPUFREQ_PRECHANGE:
/*
* Detect if the driver reported a value as "old frequency"
* which is not equal to what the cpufreq core thinks is
* "old frequency".
*/
if (policy->cur && policy->cur != freqs->old) {
pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
freqs->old, policy->cur);
freqs->old = policy->cur;
}
srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
CPUFREQ_PRECHANGE, freqs);
adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
break;
case CPUFREQ_POSTCHANGE:
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
cpumask_pr_args(policy->cpus));
for_each_cpu(cpu, policy->cpus)
trace_cpu_frequency(freqs->new, cpu);
srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
CPUFREQ_POSTCHANGE, freqs);
cpufreq_stats_record_transition(policy, freqs->new);
policy->cur = freqs->new;
}
}
/* Do post notifications when there are chances that transition has failed */
static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int transition_failed)
{
cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
if (!transition_failed)
return;
swap(freqs->old, freqs->new);
cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
}
void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs)
{
/*
* Catch double invocations of _begin() which lead to self-deadlock.
* ASYNC_NOTIFICATION drivers are left out because the cpufreq core
* doesn't invoke _begin() on their behalf, and hence the chances of
* double invocations are very low. Moreover, there are scenarios
* where these checks can emit false-positive warnings in these
* drivers; so we avoid that by skipping them altogether.
*/
WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
&& current == policy->transition_task);
wait:
wait_event(policy->transition_wait, !policy->transition_ongoing);
spin_lock(&policy->transition_lock);
if (unlikely(policy->transition_ongoing)) {
spin_unlock(&policy->transition_lock);
goto wait;
}
policy->transition_ongoing = true;
policy->transition_task = current;
spin_unlock(&policy->transition_lock);
cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
}
EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int transition_failed)
{
if (WARN_ON(!policy->transition_ongoing))
return;
cpufreq_notify_post_transition(policy, freqs, transition_failed);
arch_set_freq_scale(policy->related_cpus,
policy->cur,
policy->cpuinfo.max_freq);
policy->transition_ongoing = false;
policy->transition_task = NULL;
wake_up(&policy->transition_wait);
}
EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
/*
* Fast frequency switching status count. Positive means "enabled", negative
* means "disabled" and 0 means "not decided yet".
*/
static int cpufreq_fast_switch_count;
static DEFINE_MUTEX(cpufreq_fast_switch_lock);
static void cpufreq_list_transition_notifiers(void)
{
struct notifier_block *nb;
pr_info("Registered transition notifiers:\n");
mutex_lock(&cpufreq_transition_notifier_list.mutex);
for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
pr_info("%pS\n", nb->notifier_call);
mutex_unlock(&cpufreq_transition_notifier_list.mutex);
}
/**
* cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
* @policy: cpufreq policy to enable fast frequency switching for.
*
* Try to enable fast frequency switching for @policy.
*
* The attempt will fail if there is at least one transition notifier registered
* at this point, as fast frequency switching is quite fundamentally at odds
* with transition notifiers. Thus if successful, it will make registration of
* transition notifiers fail going forward.
*/
void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
{
lockdep_assert_held(&policy->rwsem);
if (!policy->fast_switch_possible)
return;
mutex_lock(&cpufreq_fast_switch_lock);
if (cpufreq_fast_switch_count >= 0) {
cpufreq_fast_switch_count++;
policy->fast_switch_enabled = true;
} else {
pr_warn("CPU%u: Fast frequency switching not enabled\n",
policy->cpu);
cpufreq_list_transition_notifiers();
}
mutex_unlock(&cpufreq_fast_switch_lock);
}
EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
/**
* cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
* @policy: cpufreq policy to disable fast frequency switching for.
*/
void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
{
mutex_lock(&cpufreq_fast_switch_lock);
if (policy->fast_switch_enabled) {
policy->fast_switch_enabled = false;
if (!WARN_ON(cpufreq_fast_switch_count <= 0))
cpufreq_fast_switch_count--;
}
mutex_unlock(&cpufreq_fast_switch_lock);
}
EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
static unsigned int __resolve_freq(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
unsigned int idx;
target_freq = clamp_val(target_freq, policy->min, policy->max);
if (!policy->freq_table)
return target_freq;
idx = cpufreq_frequency_table_target(policy, target_freq, relation);
policy->cached_resolved_idx = idx;
policy->cached_target_freq = target_freq;
return policy->freq_table[idx].frequency;
}
/**
* cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
* one.
* @policy: associated policy to interrogate
* @target_freq: target frequency to resolve.
*
* The target to driver frequency mapping is cached in the policy.
*
* Return: Lowest driver-supported frequency greater than or equal to the
* given target_freq, subject to policy (min/max) and driver limitations.
*/
unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
unsigned int target_freq)
{
return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_LE);
}
EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
{
unsigned int latency;
if (policy->transition_delay_us)
return policy->transition_delay_us;
latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
if (latency) {
/*
* For platforms that can change the frequency very fast (< 10
* us), the above formula gives a decent transition delay. But
* for platforms where transition_latency is in milliseconds, it
* ends up giving unrealistic values.
*
* Cap the default transition delay to 10 ms, which seems to be
* a reasonable amount of time after which we should reevaluate
* the frequency.
*/
return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
}
return LATENCY_MULTIPLIER;
}
EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
/*********************************************************************
* SYSFS INTERFACE *
*********************************************************************/
static ssize_t show_boost(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
}
static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret, enable;
ret = sscanf(buf, "%d", &enable);
if (ret != 1 || enable < 0 || enable > 1)
return -EINVAL;
if (cpufreq_boost_trigger_state(enable)) {
pr_err("%s: Cannot %s BOOST!\n",
__func__, enable ? "enable" : "disable");
return -EINVAL;
}
pr_debug("%s: cpufreq BOOST %s\n",
__func__, enable ? "enabled" : "disabled");
return count;
}
define_one_global_rw(boost);
static struct cpufreq_governor *find_governor(const char *str_governor)
{
struct cpufreq_governor *t;
for_each_governor(t)
if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
return t;
return NULL;
}
static struct cpufreq_governor *get_governor(const char *str_governor)
{
struct cpufreq_governor *t;
mutex_lock(&cpufreq_governor_mutex);
t = find_governor(str_governor);
if (!t)
goto unlock;
if (!try_module_get(t->owner))
t = NULL;
unlock:
mutex_unlock(&cpufreq_governor_mutex);
return t;
}
static unsigned int cpufreq_parse_policy(char *str_governor)
{
if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
return CPUFREQ_POLICY_PERFORMANCE;
if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
return CPUFREQ_POLICY_POWERSAVE;
return CPUFREQ_POLICY_UNKNOWN;
}
/**
* cpufreq_parse_governor - parse a governor string only for has_target()
* @str_governor: Governor name.
*/
static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
{
struct cpufreq_governor *t;
t = get_governor(str_governor);
if (t)
return t;
if (request_module("cpufreq_%s", str_governor))
return NULL;
return get_governor(str_governor);
}
/*
* cpufreq_per_cpu_attr_read() / show_##file_name() -
* print out cpufreq information
*
* Write out information from cpufreq_driver->policy[cpu]; object must be
* "unsigned int".
*/
#define show_one(file_name, object) \
static ssize_t show_##file_name \
(struct cpufreq_policy *policy, char *buf) \
{ \
return sprintf(buf, "%u\n", policy->object); \
}
show_one(cpuinfo_min_freq, cpuinfo.min_freq);
show_one(cpuinfo_max_freq, cpuinfo.max_freq);
show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
show_one(scaling_min_freq, min);
show_one(scaling_max_freq, max);
__weak unsigned int arch_freq_get_on_cpu(int cpu)
{
return 0;
}
static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
{
ssize_t ret;
unsigned int freq;
freq = arch_freq_get_on_cpu(policy->cpu);
if (freq)
ret = sprintf(buf, "%u\n", freq);
else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
else
ret = sprintf(buf, "%u\n", policy->cur);
return ret;
}
/*
* cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
*/
#define store_one(file_name, object) \
static ssize_t store_##file_name \
(struct cpufreq_policy *policy, const char *buf, size_t count) \
{ \
unsigned long val; \
int ret; \
\
ret = sscanf(buf, "%lu", &val); \
if (ret != 1) \
return -EINVAL; \
\
ret = freq_qos_update_request(policy->object##_freq_req, val);\
return ret >= 0 ? count : ret; \
}
store_one(scaling_min_freq, min);
store_one(scaling_max_freq, max);
/*
* show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
*/
static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
char *buf)
{
unsigned int cur_freq = __cpufreq_get(policy);
if (cur_freq)
return sprintf(buf, "%u\n", cur_freq);
return sprintf(buf, "<unknown>\n");
}
/*
* show_scaling_governor - show the current policy for the specified CPU
*/
static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
{
if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
return sprintf(buf, "powersave\n");
else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
return sprintf(buf, "performance\n");
else if (policy->governor)
return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
policy->governor->name);
return -EINVAL;
}
/*
* store_scaling_governor - store policy for the specified CPU
*/
static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
const char *buf, size_t count)
{
char str_governor[16];
int ret;
ret = sscanf(buf, "%15s", str_governor);
if (ret != 1)
return -EINVAL;
if (cpufreq_driver->setpolicy) {
unsigned int new_pol;
new_pol = cpufreq_parse_policy(str_governor);
if (!new_pol)
return -EINVAL;
ret = cpufreq_set_policy(policy, NULL, new_pol);
} else {
struct cpufreq_governor *new_gov;
new_gov = cpufreq_parse_governor(str_governor);
if (!new_gov)
return -EINVAL;
ret = cpufreq_set_policy(policy, new_gov,
CPUFREQ_POLICY_UNKNOWN);
module_put(new_gov->owner);
}
return ret ? ret : count;
}
/*
* show_scaling_driver - show the cpufreq driver currently loaded
*/
static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
{
return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
}
/*
* show_scaling_available_governors - show the available CPUfreq governors
*/
static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
char *buf)
{
ssize_t i = 0;
struct cpufreq_governor *t;
if (!has_target()) {
i += sprintf(buf, "performance powersave");
goto out;
}
mutex_lock(&cpufreq_governor_mutex);
for_each_governor(t) {
if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
- (CPUFREQ_NAME_LEN + 2)))
break;
i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
}
mutex_unlock(&cpufreq_governor_mutex);
out:
i += sprintf(&buf[i], "\n");
return i;
}
ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
{
ssize_t i = 0;
unsigned int cpu;
for_each_cpu(cpu, mask) {
i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u ", cpu);
if (i >= (PAGE_SIZE - 5))
break;
}
/* Remove the extra space at the end */
i--;
i += sprintf(&buf[i], "\n");
return i;
}
EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
/*
* show_related_cpus - show the CPUs affected by each transition even if
* hw coordination is in use
*/
static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
{
return cpufreq_show_cpus(policy->related_cpus, buf);
}
/*
* show_affected_cpus - show the CPUs affected by each transition
*/
static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
{
return cpufreq_show_cpus(policy->cpus, buf);
}
static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
const char *buf, size_t count)
{
unsigned int freq = 0;
unsigned int ret;
if (!policy->governor || !policy->governor->store_setspeed)
return -EINVAL;
ret = sscanf(buf, "%u", &freq);
if (ret != 1)
return -EINVAL;
policy->governor->store_setspeed(policy, freq);
return count;
}
static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
{
if (!policy->governor || !policy->governor->show_setspeed)
return sprintf(buf, "<unsupported>\n");
return policy->governor->show_setspeed(policy, buf);
}
/*
* show_bios_limit - show the current cpufreq HW/BIOS limitation
*/
static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
{
unsigned int limit;
int ret;
ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
if (!ret)
return sprintf(buf, "%u\n", limit);
return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
}
cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
cpufreq_freq_attr_ro(cpuinfo_min_freq);
cpufreq_freq_attr_ro(cpuinfo_max_freq);
cpufreq_freq_attr_ro(cpuinfo_transition_latency);
cpufreq_freq_attr_ro(scaling_available_governors);
cpufreq_freq_attr_ro(scaling_driver);
cpufreq_freq_attr_ro(scaling_cur_freq);
cpufreq_freq_attr_ro(bios_limit);
cpufreq_freq_attr_ro(related_cpus);
cpufreq_freq_attr_ro(affected_cpus);
cpufreq_freq_attr_rw(scaling_min_freq);
cpufreq_freq_attr_rw(scaling_max_freq);
cpufreq_freq_attr_rw(scaling_governor);
cpufreq_freq_attr_rw(scaling_setspeed);
static struct attribute *cpufreq_attrs[] = {
&cpuinfo_min_freq.attr,
&cpuinfo_max_freq.attr,
&cpuinfo_transition_latency.attr,
&scaling_min_freq.attr,
&scaling_max_freq.attr,
&affected_cpus.attr,
&related_cpus.attr,
&scaling_governor.attr,
&scaling_driver.attr,
&scaling_available_governors.attr,
&scaling_setspeed.attr,
NULL
};
ATTRIBUTE_GROUPS(cpufreq);
#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
#define to_attr(a) container_of(a, struct freq_attr, attr)
static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
{
struct cpufreq_policy *policy = to_policy(kobj);
struct freq_attr *fattr = to_attr(attr);
ssize_t ret = -EBUSY;
if (!fattr->show)
return -EIO;
down_read(&policy->rwsem);
if (likely(!policy_is_inactive(policy)))
ret = fattr->show(policy, buf);
up_read(&policy->rwsem);
return ret;
}
static ssize_t store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct cpufreq_policy *policy = to_policy(kobj);
struct freq_attr *fattr = to_attr(attr);
ssize_t ret = -EBUSY;
if (!fattr->store)
return -EIO;
down_write(&policy->rwsem);
if (likely(!policy_is_inactive(policy)))
ret = fattr->store(policy, buf, count);
up_write(&policy->rwsem);
return ret;
}
static void cpufreq_sysfs_release(struct kobject *kobj)
{
struct cpufreq_policy *policy = to_policy(kobj);
pr_debug("last reference is dropped\n");
complete(&policy->kobj_unregister);
}
static const struct sysfs_ops sysfs_ops = {
.show = show,
.store = store,
};
static struct kobj_type ktype_cpufreq = {
.sysfs_ops = &sysfs_ops,
.default_groups = cpufreq_groups,
.release = cpufreq_sysfs_release,
};
static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
struct device *dev)
{
if (unlikely(!dev))
return;
if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
return;
dev_dbg(dev, "%s: Adding symlink\n", __func__);
if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
dev_err(dev, "cpufreq symlink creation failed\n");
}
static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu,
struct device *dev)
{
dev_dbg(dev, "%s: Removing symlink\n", __func__);
sysfs_remove_link(&dev->kobj, "cpufreq");
cpumask_clear_cpu(cpu, policy->real_cpus);
}
static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
{
struct freq_attr **drv_attr;
int ret = 0;
/* set up files for this cpu device */
drv_attr = cpufreq_driver->attr;
while (drv_attr && *drv_attr) {
ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
if (ret)
return ret;
drv_attr++;
}
if (cpufreq_driver->get) {
ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
if (ret)
return ret;
}
ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
if (ret)
return ret;
if (cpufreq_driver->bios_limit) {
ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
if (ret)
return ret;
}
return 0;
}
static int cpufreq_init_policy(struct cpufreq_policy *policy)
{
struct cpufreq_governor *gov = NULL;
unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
int ret;
if (has_target()) {
/* Update policy governor to the one used before hotplug. */
gov = get_governor(policy->last_governor);
if (gov) {
pr_debug("Restoring governor %s for cpu %d\n",
gov->name, policy->cpu);
} else {
gov = get_governor(default_governor);
}
if (!gov) {
gov = cpufreq_default_governor();
__module_get(gov->owner);
}
} else {
/* Use the default policy if there is no last_policy. */
if (policy->last_policy) {
pol = policy->last_policy;
} else {
pol = cpufreq_parse_policy(default_governor);
/*
* In case the default governor is neither "performance"
* nor "powersave", fall back to the initial policy
* value set by the driver.
*/
if (pol == CPUFREQ_POLICY_UNKNOWN)
pol = policy->policy;
}
if (pol != CPUFREQ_POLICY_PERFORMANCE &&
pol != CPUFREQ_POLICY_POWERSAVE)
return -ENODATA;
}
ret = cpufreq_set_policy(policy, gov, pol);
if (gov)
module_put(gov->owner);
return ret;
}
static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
int ret = 0;
/* Has this CPU been taken care of already? */
if (cpumask_test_cpu(cpu, policy->cpus))
return 0;
down_write(&policy->rwsem);
if (has_target())
cpufreq_stop_governor(policy);
cpumask_set_cpu(cpu, policy->cpus);
if (has_target()) {
ret = cpufreq_start_governor(policy);
if (ret)
pr_err("%s: Failed to start governor\n", __func__);
}
up_write(&policy->rwsem);
return ret;
}
void refresh_frequency_limits(struct cpufreq_policy *policy)
{
if (!policy_is_inactive(policy)) {
pr_debug("updating policy for CPU %u\n", policy->cpu);
cpufreq_set_policy(policy, policy->governor, policy->policy);
}
}
EXPORT_SYMBOL(refresh_frequency_limits);
static void handle_update(struct work_struct *work)
{
struct cpufreq_policy *policy =
container_of(work, struct cpufreq_policy, update);
pr_debug("handle_update for cpu %u called\n", policy->cpu);
down_write(&policy->rwsem);
refresh_frequency_limits(policy);
up_write(&policy->rwsem);
}
static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
void *data)
{
struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
schedule_work(&policy->update);
return 0;
}
static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
void *data)
{
struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
schedule_work(&policy->update);
return 0;
}
static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
{
struct kobject *kobj;
struct completion *cmp;
down_write(&policy->rwsem);
cpufreq_stats_free_table(policy);
kobj = &policy->kobj;
cmp = &policy->kobj_unregister;
up_write(&policy->rwsem);
kobject_put(kobj);
/*
* We need to make sure that the underlying kobj is
* actually not referenced anymore by anybody before we
* proceed with unloading.
*/
pr_debug("waiting for dropping of refcount\n");
wait_for_completion(cmp);
pr_debug("wait complete\n");
}
static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
{
struct cpufreq_policy *policy;
struct device *dev = get_cpu_device(cpu);
int ret;
if (!dev)
return NULL;
policy = kzalloc(sizeof(*policy), GFP_KERNEL);
if (!policy)
return NULL;
if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
goto err_free_policy;
if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
goto err_free_cpumask;
if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
goto err_free_rcpumask;
init_completion(&policy->kobj_unregister);
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
cpufreq_global_kobject, "policy%u", cpu);
if (ret) {
dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
/*
* The entire policy object will be freed below, but the extra
* memory allocated for the kobject name needs to be freed by
* releasing the kobject.
*/
kobject_put(&policy->kobj);
goto err_free_real_cpus;
}
freq_constraints_init(&policy->constraints);
policy->nb_min.notifier_call = cpufreq_notifier_min;
policy->nb_max.notifier_call = cpufreq_notifier_max;
ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
&policy->nb_min);
if (ret) {
dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
ret, cpumask_pr_args(policy->cpus));
goto err_kobj_remove;
}
ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
&policy->nb_max);
if (ret) {
dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
ret, cpumask_pr_args(policy->cpus));
goto err_min_qos_notifier;
}
INIT_LIST_HEAD(&policy->policy_list);
init_rwsem(&policy->rwsem);
spin_lock_init(&policy->transition_lock);
init_waitqueue_head(&policy->transition_wait);
INIT_WORK(&policy->update, handle_update);
policy->cpu = cpu;
return policy;
err_min_qos_notifier:
freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
&policy->nb_min);
err_kobj_remove:
cpufreq_policy_put_kobj(policy);
err_free_real_cpus:
free_cpumask_var(policy->real_cpus);
err_free_rcpumask:
free_cpumask_var(policy->related_cpus);
err_free_cpumask:
free_cpumask_var(policy->cpus);
err_free_policy:
kfree(policy);
return NULL;
}
static void cpufreq_policy_free(struct cpufreq_policy *policy)
{
unsigned long flags;
int cpu;
/*
* The callers must ensure the policy is inactive by now, to avoid any
* races with show()/store() callbacks.
*/
if (unlikely(!policy_is_inactive(policy)))
pr_warn("%s: Freeing active policy\n", __func__);
/* Remove policy from list */
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_del(&policy->policy_list);
for_each_cpu(cpu, policy->related_cpus)
per_cpu(cpufreq_cpu_data, cpu) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
&policy->nb_max);
freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
&policy->nb_min);
/* Cancel any pending policy->update work before freeing the policy. */
cancel_work_sync(&policy->update);
if (policy->max_freq_req) {
/*
* Remove max_freq_req after sending CPUFREQ_REMOVE_POLICY
* notification, since CPUFREQ_CREATE_POLICY notification was
* sent after adding max_freq_req earlier.
*/
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_REMOVE_POLICY, policy);
freq_qos_remove_request(policy->max_freq_req);
}
freq_qos_remove_request(policy->min_freq_req);
kfree(policy->min_freq_req);
cpufreq_policy_put_kobj(policy);
free_cpumask_var(policy->real_cpus);
free_cpumask_var(policy->related_cpus);
free_cpumask_var(policy->cpus);
kfree(policy);
}
static int cpufreq_online(unsigned int cpu)
{
struct cpufreq_policy *policy;
bool new_policy;
unsigned long flags;
unsigned int j;
int ret;
pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
/* Check if this CPU already has a policy to manage it */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy) {
WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
if (!policy_is_inactive(policy))
return cpufreq_add_policy_cpu(policy, cpu);
/* This is the only online CPU for the policy. Start over. */
new_policy = false;
down_write(&policy->rwsem);
policy->cpu = cpu;
policy->governor = NULL;
} else {
new_policy = true;
policy = cpufreq_policy_alloc(cpu);
if (!policy)
return -ENOMEM;
down_write(&policy->rwsem);
}
if (!new_policy && cpufreq_driver->online) {
/* Recover policy->cpus using related_cpus */
cpumask_copy(policy->cpus, policy->related_cpus);
ret = cpufreq_driver->online(policy);
if (ret) {
pr_debug("%s: %d: initialization failed\n", __func__,
__LINE__);
goto out_exit_policy;
}
} else {
cpumask_copy(policy->cpus, cpumask_of(cpu));
/*
* Call driver. From then on the cpufreq must be able
* to accept all calls to ->verify and ->setpolicy for this CPU.
*/
ret = cpufreq_driver->init(policy);
if (ret) {
pr_debug("%s: %d: initialization failed\n", __func__,
__LINE__);
goto out_free_policy;
}
/*
* The initialization has succeeded and the policy is online.
* If there is a problem with its frequency table, take it
* offline and drop it.
*/
ret = cpufreq_table_validate_and_sort(policy);
if (ret)
goto out_offline_policy;
/* related_cpus should at least include policy->cpus. */
cpumask_copy(policy->related_cpus, policy->cpus);
}
/*
* affected cpus must always be the one, which are online. We aren't
* managing offline cpus here.
*/
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
if (new_policy) {
for_each_cpu(j, policy->related_cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
add_cpu_dev_symlink(policy, j, get_cpu_device(j));
}
policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
GFP_KERNEL);
if (!policy->min_freq_req) {
ret = -ENOMEM;
goto out_destroy_policy;
}
ret = freq_qos_add_request(&policy->constraints,
policy->min_freq_req, FREQ_QOS_MIN,
FREQ_QOS_MIN_DEFAULT_VALUE);
if (ret < 0) {
/*
* So we don't call freq_qos_remove_request() for an
* uninitialized request.
*/
kfree(policy->min_freq_req);
policy->min_freq_req = NULL;
goto out_destroy_policy;
}
/*
* This must be initialized right here to avoid calling
* freq_qos_remove_request() on uninitialized request in case
* of errors.
*/
policy->max_freq_req = policy->min_freq_req + 1;
ret = freq_qos_add_request(&policy->constraints,
policy->max_freq_req, FREQ_QOS_MAX,
FREQ_QOS_MAX_DEFAULT_VALUE);
if (ret < 0) {
policy->max_freq_req = NULL;
goto out_destroy_policy;
}
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
}
if (cpufreq_driver->get && has_target()) {
policy->cur = cpufreq_driver->get(policy->cpu);
if (!policy->cur) {
ret = -EIO;
pr_err("%s: ->get() failed\n", __func__);
goto out_destroy_policy;
}
}
/*
* Sometimes boot loaders set CPU frequency to a value outside of
* frequency table present with cpufreq core. In such cases CPU might be
* unstable if it has to run on that frequency for long duration of time
* and so its better to set it to a frequency which is specified in
* freq-table. This also makes cpufreq stats inconsistent as
* cpufreq-stats would fail to register because current frequency of CPU
* isn't found in freq-table.
*
* Because we don't want this change to effect boot process badly, we go
* for the next freq which is >= policy->cur ('cur' must be set by now,
* otherwise we will end up setting freq to lowest of the table as 'cur'
* is initialized to zero).
*
* We are passing target-freq as "policy->cur - 1" otherwise
* __cpufreq_driver_target() would simply fail, as policy->cur will be
* equal to target-freq.
*/
if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
&& has_target()) {
unsigned int old_freq = policy->cur;
/* Are we running at unknown frequency ? */
ret = cpufreq_frequency_table_get_index(policy, old_freq);
if (ret == -EINVAL) {
ret = __cpufreq_driver_target(policy, old_freq - 1,
CPUFREQ_RELATION_L);
/*
* Reaching here after boot in a few seconds may not
* mean that system will remain stable at "unknown"
* frequency for longer duration. Hence, a BUG_ON().
*/
BUG_ON(ret);
pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
__func__, policy->cpu, old_freq, policy->cur);
}
}
if (new_policy) {
ret = cpufreq_add_dev_interface(policy);
if (ret)
goto out_destroy_policy;
cpufreq_stats_create_table(policy);
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_add(&policy->policy_list, &cpufreq_policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
/*
* Register with the energy model before
* sched_cpufreq_governor_change() is called, which will result
* in rebuilding of the sched domains, which should only be done
* once the energy model is properly initialized for the policy
* first.
*
* Also, this should be called before the policy is registered
* with cooling framework.
*/
if (cpufreq_driver->register_em)
cpufreq_driver->register_em(policy);
}
ret = cpufreq_init_policy(policy);
if (ret) {
pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
__func__, cpu, ret);
goto out_destroy_policy;
}
up_write(&policy->rwsem);
kobject_uevent(&policy->kobj, KOBJ_ADD);
/* Callback for handling stuff after policy is ready */
if (cpufreq_driver->ready)
cpufreq_driver->ready(policy);
if (cpufreq_thermal_control_enabled(cpufreq_driver))
policy->cdev = of_cpufreq_cooling_register(policy);
pr_debug("initialization complete\n");
return 0;
out_destroy_policy:
for_each_cpu(j, policy->real_cpus)
remove_cpu_dev_symlink(policy, j, get_cpu_device(j));
out_offline_policy:
if (cpufreq_driver->offline)
cpufreq_driver->offline(policy);
out_exit_policy:
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
out_free_policy:
cpumask_clear(policy->cpus);
up_write(&policy->rwsem);
cpufreq_policy_free(policy);
return ret;
}
/**
* cpufreq_add_dev - the cpufreq interface for a CPU device.
* @dev: CPU device.
* @sif: Subsystem interface structure pointer (not used)
*/
static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
{
struct cpufreq_policy *policy;
unsigned cpu = dev->id;
int ret;
dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
if (cpu_online(cpu)) {
ret = cpufreq_online(cpu);
if (ret)
return ret;
}
/* Create sysfs link on CPU registration */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy)
add_cpu_dev_symlink(policy, cpu, dev);
return 0;
}
static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy)
{
int ret;
if (has_target())
cpufreq_stop_governor(policy);
cpumask_clear_cpu(cpu, policy->cpus);
if (!policy_is_inactive(policy)) {
/* Nominate a new CPU if necessary. */
if (cpu == policy->cpu)
policy->cpu = cpumask_any(policy->cpus);
/* Start the governor again for the active policy. */
if (has_target()) {
ret = cpufreq_start_governor(policy);
if (ret)
pr_err("%s: Failed to start governor\n", __func__);
}
return;
}
if (has_target())
strncpy(policy->last_governor, policy->governor->name,
CPUFREQ_NAME_LEN);
else
policy->last_policy = policy->policy;
if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
cpufreq_cooling_unregister(policy->cdev);
policy->cdev = NULL;
}
if (has_target())
cpufreq_exit_governor(policy);
/*
* Perform the ->offline() during light-weight tear-down, as
* that allows fast recovery when the CPU comes back.
*/
if (cpufreq_driver->offline) {
cpufreq_driver->offline(policy);
} else if (cpufreq_driver->exit) {
cpufreq_driver->exit(policy);
policy->freq_table = NULL;
}
}
static int cpufreq_offline(unsigned int cpu)
{
struct cpufreq_policy *policy;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
policy = cpufreq_cpu_get_raw(cpu);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
return 0;
}
down_write(&policy->rwsem);
__cpufreq_offline(cpu, policy);
up_write(&policy->rwsem);
return 0;
}
/*
* cpufreq_remove_dev - remove a CPU device
*
* Removes the cpufreq interface for a CPU device.
*/
static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
if (!policy)
return;
down_write(&policy->rwsem);
if (cpu_online(cpu))
__cpufreq_offline(cpu, policy);
remove_cpu_dev_symlink(policy, cpu, dev);
if (!cpumask_empty(policy->real_cpus)) {
up_write(&policy->rwsem);
return;
}
/* We did light-weight exit earlier, do full tear down now */
if (cpufreq_driver->offline)
cpufreq_driver->exit(policy);
up_write(&policy->rwsem);
cpufreq_policy_free(policy);
}
/**
* cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
* @policy: Policy managing CPUs.
* @new_freq: New CPU frequency.
*
* Adjust to the current frequency first and clean up later by either calling
* cpufreq_update_policy(), or scheduling handle_update().
*/
static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
unsigned int new_freq)
{
struct cpufreq_freqs freqs;
pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
policy->cur, new_freq);
freqs.old = policy->cur;
freqs.new = new_freq;
cpufreq_freq_transition_begin(policy, &freqs);
cpufreq_freq_transition_end(policy, &freqs, 0);
}
static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
{
unsigned int new_freq;
new_freq = cpufreq_driver->get(policy->cpu);
if (!new_freq)
return 0;
/*
* If fast frequency switching is used with the given policy, the check
* against policy->cur is pointless, so skip it in that case.
*/
if (policy->fast_switch_enabled || !has_target())
return new_freq;
if (policy->cur != new_freq) {
/*
* For some platforms, the frequency returned by hardware may be
* slightly different from what is provided in the frequency
* table, for example hardware may return 499 MHz instead of 500
* MHz. In such cases it is better to avoid getting into
* unnecessary frequency updates.
*/
if (abs(policy->cur - new_freq) < HZ_PER_MHZ)
return policy->cur;
cpufreq_out_of_sync(policy, new_freq);
if (update)
schedule_work(&policy->update);
}
return new_freq;
}
/**
* cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
* @cpu: CPU number
*
* This is the last known freq, without actually getting it from the driver.
* Return value will be same as what is shown in scaling_cur_freq in sysfs.
*/
unsigned int cpufreq_quick_get(unsigned int cpu)
{
struct cpufreq_policy *policy;
unsigned int ret_freq = 0;
unsigned long flags;
read_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
ret_freq = cpufreq_driver->get(cpu);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
return ret_freq;
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
policy = cpufreq_cpu_get(cpu);
if (policy) {
ret_freq = policy->cur;
cpufreq_cpu_put(policy);
}
return ret_freq;
}
EXPORT_SYMBOL(cpufreq_quick_get);
/**
* cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
* @cpu: CPU number
*
* Just return the max possible frequency for a given CPU.
*/
unsigned int cpufreq_quick_get_max(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
unsigned int ret_freq = 0;
if (policy) {
ret_freq = policy->max;
cpufreq_cpu_put(policy);
}
return ret_freq;
}
EXPORT_SYMBOL(cpufreq_quick_get_max);
/**
* cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
* @cpu: CPU number
*
* The default return value is the max_freq field of cpuinfo.
*/
__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
unsigned int ret_freq = 0;
if (policy) {
ret_freq = policy->cpuinfo.max_freq;
cpufreq_cpu_put(policy);
}
return ret_freq;
}
EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
{
if (unlikely(policy_is_inactive(policy)))
return 0;
return cpufreq_verify_current_freq(policy, true);
}
/**
* cpufreq_get - get the current CPU frequency (in kHz)
* @cpu: CPU number
*
* Get the CPU current (static) CPU frequency
*/
unsigned int cpufreq_get(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
unsigned int ret_freq = 0;
if (policy) {
down_read(&policy->rwsem);
if (cpufreq_driver->get)
ret_freq = __cpufreq_get(policy);
up_read(&policy->rwsem);
cpufreq_cpu_put(policy);
}
return ret_freq;
}
EXPORT_SYMBOL(cpufreq_get);
static struct subsys_interface cpufreq_interface = {
.name = "cpufreq",
.subsys = &cpu_subsys,
.add_dev = cpufreq_add_dev,
.remove_dev = cpufreq_remove_dev,
};
/*
* In case platform wants some specific frequency to be configured
* during suspend..
*/
int cpufreq_generic_suspend(struct cpufreq_policy *policy)
{
int ret;
if (!policy->suspend_freq) {
pr_debug("%s: suspend_freq not defined\n", __func__);
return 0;
}
pr_debug("%s: Setting suspend-freq: %u\n", __func__,
policy->suspend_freq);
ret = __cpufreq_driver_target(policy, policy->suspend_freq,
CPUFREQ_RELATION_H);
if (ret)
pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
__func__, policy->suspend_freq, ret);
return ret;
}
EXPORT_SYMBOL(cpufreq_generic_suspend);
/**
* cpufreq_suspend() - Suspend CPUFreq governors.
*
* Called during system wide Suspend/Hibernate cycles for suspending governors
* as some platforms can't change frequency after this point in suspend cycle.
* Because some of the devices (like: i2c, regulators, etc) they use for
* changing frequency are suspended quickly after this point.
*/
void cpufreq_suspend(void)
{
struct cpufreq_policy *policy;
if (!cpufreq_driver)
return;
if (!has_target() && !cpufreq_driver->suspend)
goto suspend;
pr_debug("%s: Suspending Governors\n", __func__);
for_each_active_policy(policy) {
if (has_target()) {
down_write(&policy->rwsem);
cpufreq_stop_governor(policy);
up_write(&policy->rwsem);
}
if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
pr_err("%s: Failed to suspend driver: %s\n", __func__,
cpufreq_driver->name);
}
suspend:
cpufreq_suspended = true;
}
/**
* cpufreq_resume() - Resume CPUFreq governors.
*
* Called during system wide Suspend/Hibernate cycle for resuming governors that
* are suspended with cpufreq_suspend().
*/
void cpufreq_resume(void)
{
struct cpufreq_policy *policy;
int ret;
if (!cpufreq_driver)
return;
if (unlikely(!cpufreq_suspended))
return;
cpufreq_suspended = false;
if (!has_target() && !cpufreq_driver->resume)
return;
pr_debug("%s: Resuming Governors\n", __func__);
for_each_active_policy(policy) {
if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
pr_err("%s: Failed to resume driver: %p\n", __func__,
policy);
} else if (has_target()) {
down_write(&policy->rwsem);
ret = cpufreq_start_governor(policy);
up_write(&policy->rwsem);
if (ret)
pr_err("%s: Failed to start governor for policy: %p\n",
__func__, policy);
}
}
}
/**
* cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
* @flags: Flags to test against the current cpufreq driver's flags.
*
* Assumes that the driver is there, so callers must ensure that this is the
* case.
*/
bool cpufreq_driver_test_flags(u16 flags)
{
return !!(cpufreq_driver->flags & flags);
}
/**
* cpufreq_get_current_driver - Return the current driver's name.
*
* Return the name string of the currently registered cpufreq driver or NULL if
* none.
*/
const char *cpufreq_get_current_driver(void)
{
if (cpufreq_driver)
return cpufreq_driver->name;
return NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
/**
* cpufreq_get_driver_data - Return current driver data.
*
* Return the private data of the currently registered cpufreq driver, or NULL
* if no cpufreq driver has been registered.
*/
void *cpufreq_get_driver_data(void)
{
if (cpufreq_driver)
return cpufreq_driver->driver_data;
return NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
/*********************************************************************
* NOTIFIER LISTS INTERFACE *
*********************************************************************/
/**
* cpufreq_register_notifier - Register a notifier with cpufreq.
* @nb: notifier function to register.
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
*
* Add a notifier to one of two lists: either a list of notifiers that run on
* clock rate changes (once before and once after every transition), or a list
* of notifiers that ron on cpufreq policy changes.
*
* This function may sleep and it has the same return values as
* blocking_notifier_chain_register().
*/
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
{
int ret;
if (cpufreq_disabled())
return -EINVAL;
switch (list) {
case CPUFREQ_TRANSITION_NOTIFIER:
mutex_lock(&cpufreq_fast_switch_lock);
if (cpufreq_fast_switch_count > 0) {
mutex_unlock(&cpufreq_fast_switch_lock);
return -EBUSY;
}
ret = srcu_notifier_chain_register(
&cpufreq_transition_notifier_list, nb);
if (!ret)
cpufreq_fast_switch_count--;
mutex_unlock(&cpufreq_fast_switch_lock);
break;
case CPUFREQ_POLICY_NOTIFIER:
ret = blocking_notifier_chain_register(
&cpufreq_policy_notifier_list, nb);
break;
default:
ret = -EINVAL;
}
return ret;
}
EXPORT_SYMBOL(cpufreq_register_notifier);
/**
* cpufreq_unregister_notifier - Unregister a notifier from cpufreq.
* @nb: notifier block to be unregistered.
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
*
* Remove a notifier from one of the cpufreq notifier lists.
*
* This function may sleep and it has the same return values as
* blocking_notifier_chain_unregister().
*/
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
{
int ret;
if (cpufreq_disabled())
return -EINVAL;
switch (list) {
case CPUFREQ_TRANSITION_NOTIFIER:
mutex_lock(&cpufreq_fast_switch_lock);
ret = srcu_notifier_chain_unregister(
&cpufreq_transition_notifier_list, nb);
if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
cpufreq_fast_switch_count++;
mutex_unlock(&cpufreq_fast_switch_lock);
break;
case CPUFREQ_POLICY_NOTIFIER:
ret = blocking_notifier_chain_unregister(
&cpufreq_policy_notifier_list, nb);
break;
default:
ret = -EINVAL;
}
return ret;
}
EXPORT_SYMBOL(cpufreq_unregister_notifier);
/*********************************************************************
* GOVERNORS *
*********************************************************************/
/**
* cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
* @policy: cpufreq policy to switch the frequency for.
* @target_freq: New frequency to set (may be approximate).
*
* Carry out a fast frequency switch without sleeping.
*
* The driver's ->fast_switch() callback invoked by this function must be
* suitable for being called from within RCU-sched read-side critical sections
* and it is expected to select the minimum available frequency greater than or
* equal to @target_freq (CPUFREQ_RELATION_L).
*
* This function must not be called if policy->fast_switch_enabled is unset.
*
* Governors calling this function must guarantee that it will never be invoked
* twice in parallel for the same policy and that it will never be called in
* parallel with either ->target() or ->target_index() for the same policy.
*
* Returns the actual frequency set for the CPU.
*
* If 0 is returned by the driver's ->fast_switch() callback to indicate an
* error condition, the hardware configuration must be preserved.
*/
unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
unsigned int target_freq)
{
unsigned int freq;
int cpu;
target_freq = clamp_val(target_freq, policy->min, policy->max);
freq = cpufreq_driver->fast_switch(policy, target_freq);
if (!freq)
return 0;
policy->cur = freq;
arch_set_freq_scale(policy->related_cpus, freq,
policy->cpuinfo.max_freq);
cpufreq_stats_record_transition(policy, freq);
if (trace_cpu_frequency_enabled()) {
for_each_cpu(cpu, policy->cpus)
trace_cpu_frequency(freq, cpu);
}
return freq;
}
EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
/**
* cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
* @cpu: Target CPU.
* @min_perf: Minimum (required) performance level (units of @capacity).
* @target_perf: Target (desired) performance level (units of @capacity).
* @capacity: Capacity of the target CPU.
*
* Carry out a fast performance level switch of @cpu without sleeping.
*
* The driver's ->adjust_perf() callback invoked by this function must be
* suitable for being called from within RCU-sched read-side critical sections
* and it is expected to select a suitable performance level equal to or above
* @min_perf and preferably equal to or below @target_perf.
*
* This function must not be called if policy->fast_switch_enabled is unset.
*
* Governors calling this function must guarantee that it will never be invoked
* twice in parallel for the same CPU and that it will never be called in
* parallel with either ->target() or ->target_index() or ->fast_switch() for
* the same CPU.
*/
void cpufreq_driver_adjust_perf(unsigned int cpu,
unsigned long min_perf,
unsigned long target_perf,
unsigned long capacity)
{
cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
}
/**
* cpufreq_driver_has_adjust_perf - Check "direct fast switch" callback.
*
* Return 'true' if the ->adjust_perf callback is present for the
* current driver or 'false' otherwise.
*/
bool cpufreq_driver_has_adjust_perf(void)
{
return !!cpufreq_driver->adjust_perf;
}
/* Must set freqs->new to intermediate frequency */
static int __target_intermediate(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int index)
{
int ret;
freqs->new = cpufreq_driver->get_intermediate(policy, index);
/* We don't need to switch to intermediate freq */
if (!freqs->new)
return 0;
pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
__func__, policy->cpu, freqs->old, freqs->new);
cpufreq_freq_transition_begin(policy, freqs);
ret = cpufreq_driver->target_intermediate(policy, index);
cpufreq_freq_transition_end(policy, freqs, ret);
if (ret)
pr_err("%s: Failed to change to intermediate frequency: %d\n",
__func__, ret);
return ret;
}
static int __target_index(struct cpufreq_policy *policy, int index)
{
struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
unsigned int restore_freq, intermediate_freq = 0;
unsigned int newfreq = policy->freq_table[index].frequency;
int retval = -EINVAL;
bool notify;
if (newfreq == policy->cur)
return 0;
/* Save last value to restore later on errors */
restore_freq = policy->cur;
notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
if (notify) {
/* Handle switching to intermediate frequency */
if (cpufreq_driver->get_intermediate) {
retval = __target_intermediate(policy, &freqs, index);
if (retval)
return retval;
intermediate_freq = freqs.new;
/* Set old freq to intermediate */
if (intermediate_freq)
freqs.old = freqs.new;
}
freqs.new = newfreq;
pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
__func__, policy->cpu, freqs.old, freqs.new);
cpufreq_freq_transition_begin(policy, &freqs);
}
retval = cpufreq_driver->target_index(policy, index);
if (retval)
pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
retval);
if (notify) {
cpufreq_freq_transition_end(policy, &freqs, retval);
/*
* Failed after setting to intermediate freq? Driver should have
* reverted back to initial frequency and so should we. Check
* here for intermediate_freq instead of get_intermediate, in
* case we haven't switched to intermediate freq at all.
*/
if (unlikely(retval && intermediate_freq)) {
freqs.old = intermediate_freq;
freqs.new = restore_freq;
cpufreq_freq_transition_begin(policy, &freqs);
cpufreq_freq_transition_end(policy, &freqs, 0);
}
}
return retval;
}
int __cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int old_target_freq = target_freq;
if (cpufreq_disabled())
return -ENODEV;
target_freq = __resolve_freq(policy, target_freq, relation);
pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
policy->cpu, target_freq, relation, old_target_freq);
/*
* This might look like a redundant call as we are checking it again
* after finding index. But it is left intentionally for cases where
* exactly same freq is called again and so we can save on few function
* calls.
*/
if (target_freq == policy->cur &&
!(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS))
return 0;
if (cpufreq_driver->target) {
/*
* If the driver hasn't setup a single inefficient frequency,
* it's unlikely it knows how to decode CPUFREQ_RELATION_E.
*/
if (!policy->efficiencies_available)
relation &= ~CPUFREQ_RELATION_E;
return cpufreq_driver->target(policy, target_freq, relation);
}
if (!cpufreq_driver->target_index)
return -EINVAL;
return __target_index(policy, policy->cached_resolved_idx);
}
EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
int cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
int ret;
down_write(&policy->rwsem);
ret = __cpufreq_driver_target(policy, target_freq, relation);
up_write(&policy->rwsem);
return ret;
}
EXPORT_SYMBOL_GPL(cpufreq_driver_target);
__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
{
return NULL;
}
static int cpufreq_init_governor(struct cpufreq_policy *policy)
{
int ret;
/* Don't start any governor operations if we are entering suspend */
if (cpufreq_suspended)
return 0;
/*
* Governor might not be initiated here if ACPI _PPC changed
* notification happened, so check it.
*/
if (!policy->governor)
return -EINVAL;
/* Platform doesn't want dynamic frequency switching ? */
if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING &&
cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
struct cpufreq_governor *gov = cpufreq_fallback_governor();
if (gov) {
pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
policy->governor->name, gov->name);
policy->governor = gov;
} else {
return -EINVAL;
}
}
if (!try_module_get(policy->governor->owner))
return -EINVAL;
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
if (policy->governor->init) {
ret = policy->governor->init(policy);
if (ret) {
module_put(policy->governor->owner);
return ret;
}
}
policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET);
return 0;
}
static void cpufreq_exit_governor(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
if (policy->governor->exit)
policy->governor->exit(policy);
module_put(policy->governor->owner);
}
int cpufreq_start_governor(struct cpufreq_policy *policy)
{
int ret;
if (cpufreq_suspended)
return 0;
if (!policy->governor)
return -EINVAL;
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
if (cpufreq_driver->get)
cpufreq_verify_current_freq(policy, false);
if (policy->governor->start) {
ret = policy->governor->start(policy);
if (ret)
return ret;
}
if (policy->governor->limits)
policy->governor->limits(policy);
return 0;
}
void cpufreq_stop_governor(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
if (policy->governor->stop)
policy->governor->stop(policy);
}
static void cpufreq_governor_limits(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
if (policy->governor->limits)
policy->governor->limits(policy);
}
int cpufreq_register_governor(struct cpufreq_governor *governor)
{
int err;
if (!governor)
return -EINVAL;
if (cpufreq_disabled())
return -ENODEV;
mutex_lock(&cpufreq_governor_mutex);
err = -EBUSY;
if (!find_governor(governor->name)) {
err = 0;
list_add(&governor->governor_list, &cpufreq_governor_list);
}
mutex_unlock(&cpufreq_governor_mutex);
return err;
}
EXPORT_SYMBOL_GPL(cpufreq_register_governor);
void cpufreq_unregister_governor(struct cpufreq_governor *governor)
{
struct cpufreq_policy *policy;
unsigned long flags;
if (!governor)
return;
if (cpufreq_disabled())
return;
/* clear last_governor for all inactive policies */
read_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_inactive_policy(policy) {
if (!strcmp(policy->last_governor, governor->name)) {
policy->governor = NULL;
strcpy(policy->last_governor, "\0");
}
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
mutex_lock(&cpufreq_governor_mutex);
list_del(&governor->governor_list);
mutex_unlock(&cpufreq_governor_mutex);
}
EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
/*********************************************************************
* POLICY INTERFACE *
*********************************************************************/
/**
* cpufreq_get_policy - get the current cpufreq_policy
* @policy: struct cpufreq_policy into which the current cpufreq_policy
* is written
* @cpu: CPU to find the policy for
*
* Reads the current cpufreq policy.
*/
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
{
struct cpufreq_policy *cpu_policy;
if (!policy)
return -EINVAL;
cpu_policy = cpufreq_cpu_get(cpu);
if (!cpu_policy)
return -EINVAL;
memcpy(policy, cpu_policy, sizeof(*policy));
cpufreq_cpu_put(cpu_policy);
return 0;
}
EXPORT_SYMBOL(cpufreq_get_policy);
/**
* cpufreq_set_policy - Modify cpufreq policy parameters.
* @policy: Policy object to modify.
* @new_gov: Policy governor pointer.
* @new_pol: Policy value (for drivers with built-in governors).
*
* Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
* limits to be set for the policy, update @policy with the verified limits
* values and either invoke the driver's ->setpolicy() callback (if present) or
* carry out a governor update for @policy. That is, run the current governor's
* ->limits() callback (if @new_gov points to the same object as the one in
* @policy) or replace the governor for @policy with @new_gov.
*
* The cpuinfo part of @policy is not updated by this function.
*/
static int cpufreq_set_policy(struct cpufreq_policy *policy,
struct cpufreq_governor *new_gov,
unsigned int new_pol)
{
struct cpufreq_policy_data new_data;
struct cpufreq_governor *old_gov;
int ret;
memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
new_data.freq_table = policy->freq_table;
new_data.cpu = policy->cpu;
/*
* PM QoS framework collects all the requests from users and provide us
* the final aggregated value here.
*/
new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
new_data.cpu, new_data.min, new_data.max);
/*
* Verify that the CPU speed can be set within these limits and make sure
* that min <= max.
*/
ret = cpufreq_driver->verify(&new_data);
if (ret)
return ret;
/*
* Resolve policy min/max to available frequencies. It ensures
* no frequency resolution will neither overshoot the requested maximum
* nor undershoot the requested minimum.
*/
policy->min = new_data.min;
policy->max = new_data.max;
policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
trace_cpu_frequency_limits(policy);
policy->cached_target_freq = UINT_MAX;
pr_debug("new min and max freqs are %u - %u kHz\n",
policy->min, policy->max);
if (cpufreq_driver->setpolicy) {
policy->policy = new_pol;
pr_debug("setting range\n");
return cpufreq_driver->setpolicy(policy);
}
if (new_gov == policy->governor) {
pr_debug("governor limits update\n");
cpufreq_governor_limits(policy);
return 0;
}
pr_debug("governor switch\n");
/* save old, working values */
old_gov = policy->governor;
/* end old governor */
if (old_gov) {
cpufreq_stop_governor(policy);
cpufreq_exit_governor(policy);
}
/* start new governor */
policy->governor = new_gov;
ret = cpufreq_init_governor(policy);
if (!ret) {
ret = cpufreq_start_governor(policy);
if (!ret) {
pr_debug("governor change\n");
sched_cpufreq_governor_change(policy, old_gov);
return 0;
}
cpufreq_exit_governor(policy);
}
/* new governor failed, so re-start old one */
pr_debug("starting governor %s failed\n", policy->governor->name);
if (old_gov) {
policy->governor = old_gov;
if (cpufreq_init_governor(policy))
policy->governor = NULL;
else
cpufreq_start_governor(policy);
}
return ret;
}
/**
* cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
* @cpu: CPU to re-evaluate the policy for.
*
* Update the current frequency for the cpufreq policy of @cpu and use
* cpufreq_set_policy() to re-apply the min and max limits, which triggers the
* evaluation of policy notifiers and the cpufreq driver's ->verify() callback
* for the policy in question, among other things.
*/
void cpufreq_update_policy(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
if (!policy)
return;
/*
* BIOS might change freq behind our back
* -> ask driver for current freq and notify governors about a change
*/
if (cpufreq_driver->get && has_target() &&
(cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
goto unlock;
refresh_frequency_limits(policy);
unlock:
cpufreq_cpu_release(policy);
}
EXPORT_SYMBOL(cpufreq_update_policy);
/**
* cpufreq_update_limits - Update policy limits for a given CPU.
* @cpu: CPU to update the policy limits for.
*
* Invoke the driver's ->update_limits callback if present or call
* cpufreq_update_policy() for @cpu.
*/
void cpufreq_update_limits(unsigned int cpu)
{
if (cpufreq_driver->update_limits)
cpufreq_driver->update_limits(cpu);
else
cpufreq_update_policy(cpu);
}
EXPORT_SYMBOL_GPL(cpufreq_update_limits);
/*********************************************************************
* BOOST *
*********************************************************************/
static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
{
int ret;
if (!policy->freq_table)
return -ENXIO;
ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
if (ret) {
pr_err("%s: Policy frequency update failed\n", __func__);
return ret;
}
ret = freq_qos_update_request(policy->max_freq_req, policy->max);
if (ret < 0)
return ret;
return 0;
}
int cpufreq_boost_trigger_state(int state)
{
struct cpufreq_policy *policy;
unsigned long flags;
int ret = 0;
if (cpufreq_driver->boost_enabled == state)
return 0;
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver->boost_enabled = state;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
cpus_read_lock();
for_each_active_policy(policy) {
ret = cpufreq_driver->set_boost(policy, state);
if (ret)
goto err_reset_state;
}
cpus_read_unlock();
return 0;
err_reset_state:
cpus_read_unlock();
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver->boost_enabled = !state;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
pr_err("%s: Cannot %s BOOST\n",
__func__, state ? "enable" : "disable");
return ret;
}
static bool cpufreq_boost_supported(void)
{
return cpufreq_driver->set_boost;
}
static int create_boost_sysfs_file(void)
{
int ret;
ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
if (ret)
pr_err("%s: cannot register global BOOST sysfs file\n",
__func__);
return ret;
}
static void remove_boost_sysfs_file(void)
{
if (cpufreq_boost_supported())
sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
}
int cpufreq_enable_boost_support(void)
{
if (!cpufreq_driver)
return -EINVAL;
if (cpufreq_boost_supported())
return 0;
cpufreq_driver->set_boost = cpufreq_boost_set_sw;
/* This will get removed on driver unregister */
return create_boost_sysfs_file();
}
EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
int cpufreq_boost_enabled(void)
{
return cpufreq_driver->boost_enabled;
}
EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
*********************************************************************/
static enum cpuhp_state hp_online;
static int cpuhp_cpufreq_online(unsigned int cpu)
{
cpufreq_online(cpu);
return 0;
}
static int cpuhp_cpufreq_offline(unsigned int cpu)
{
cpufreq_offline(cpu);
return 0;
}
/**
* cpufreq_register_driver - register a CPU Frequency driver
* @driver_data: A struct cpufreq_driver containing the values#
* submitted by the CPU Frequency driver.
*
* Registers a CPU Frequency driver to this core code. This code
* returns zero on success, -EEXIST when another driver got here first
* (and isn't unregistered in the meantime).
*
*/
int cpufreq_register_driver(struct cpufreq_driver *driver_data)
{
unsigned long flags;
int ret;
if (cpufreq_disabled())
return -ENODEV;
/*
* The cpufreq core depends heavily on the availability of device
* structure, make sure they are available before proceeding further.
*/
if (!get_cpu_device(0))
return -EPROBE_DEFER;
if (!driver_data || !driver_data->verify || !driver_data->init ||
!(driver_data->setpolicy || driver_data->target_index ||
driver_data->target) ||
(driver_data->setpolicy && (driver_data->target_index ||
driver_data->target)) ||
(!driver_data->get_intermediate != !driver_data->target_intermediate) ||
(!driver_data->online != !driver_data->offline))
return -EINVAL;
pr_debug("trying to register driver %s\n", driver_data->name);
/* Protect against concurrent CPU online/offline. */
cpus_read_lock();
write_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
ret = -EEXIST;
goto out;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
/*
* Mark support for the scheduler's frequency invariance engine for
* drivers that implement target(), target_index() or fast_switch().
*/
if (!cpufreq_driver->setpolicy) {
static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
pr_debug("supports frequency invariance");
}
if (driver_data->setpolicy)
driver_data->flags |= CPUFREQ_CONST_LOOPS;
if (cpufreq_boost_supported()) {
ret = create_boost_sysfs_file();
if (ret)
goto err_null_driver;
}
ret = subsys_interface_register(&cpufreq_interface);
if (ret)
goto err_boost_unreg;
if (unlikely(list_empty(&cpufreq_policy_list))) {
/* if all ->init() calls failed, unregister */
ret = -ENODEV;
pr_debug("%s: No CPU initialized for driver %s\n", __func__,
driver_data->name);
goto err_if_unreg;
}
ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
"cpufreq:online",
cpuhp_cpufreq_online,
cpuhp_cpufreq_offline);
if (ret < 0)
goto err_if_unreg;
hp_online = ret;
ret = 0;
pr_debug("driver %s up and running\n", driver_data->name);
goto out;
err_if_unreg:
subsys_interface_unregister(&cpufreq_interface);
err_boost_unreg:
remove_boost_sysfs_file();
err_null_driver:
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
out:
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(cpufreq_register_driver);
/*
* cpufreq_unregister_driver - unregister the current CPUFreq driver
*
* Unregister the current CPUFreq driver. Only call this if you have
* the right to do so, i.e. if you have succeeded in initialising before!
* Returns zero if successful, and -EINVAL if the cpufreq_driver is
* currently not initialised.
*/
int cpufreq_unregister_driver(struct cpufreq_driver *driver)
{
unsigned long flags;
if (!cpufreq_driver || (driver != cpufreq_driver))
return -EINVAL;
pr_debug("unregistering driver %s\n", driver->name);
/* Protect against concurrent cpu hotplug */
cpus_read_lock();
subsys_interface_unregister(&cpufreq_interface);
remove_boost_sysfs_file();
static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
cpuhp_remove_state_nocalls_cpuslocked(hp_online);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
cpus_read_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
static int __init cpufreq_core_init(void)
{
struct cpufreq_governor *gov = cpufreq_default_governor();
if (cpufreq_disabled())
return -ENODEV;
cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
BUG_ON(!cpufreq_global_kobject);
if (!strlen(default_governor))
strncpy(default_governor, gov->name, CPUFREQ_NAME_LEN);
return 0;
}
module_param(off, int, 0444);
module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
core_initcall(cpufreq_core_init);