- 根目录:
- drivers
- cpufreq
- cpufreq.c
/*
* linux/drivers/cpufreq/cpufreq.c
*
* Copyright (C) 2001 Russell King
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
*
* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/syscore_ops.h>
#include <trace/events/power.h>
/**
* 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);
#ifdef CONFIG_HOTPLUG_CPU
/* This one keeps track of the previously set governor of a removed CPU */
static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
#endif
static DEFINE_RWLOCK(cpufreq_driver_lock);
/*
* cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
* all cpufreq/hotplug/workqueue/etc related lock issues.
*
* The rules for this semaphore:
* - Any routine that wants to read from the policy structure will
* do a down_read on this semaphore.
* - Any routine that will write to the policy structure and/or may take away
* the policy altogether (eg. CPU hotplug), will hold this lock in write
* mode before doing so.
*
* Additional rules:
* - Governor routines that can be called in cpufreq hotplug path should not
* take this sem as top level hotplug notifier handler takes this.
* - Lock should not be held across
* __cpufreq_governor(data, CPUFREQ_GOV_STOP);
*/
static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
#define lock_policy_rwsem(mode, cpu) \
static int lock_policy_rwsem_##mode(int cpu) \
{ \
int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
BUG_ON(policy_cpu == -1); \
down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
\
return 0; \
}
lock_policy_rwsem(read, cpu);
lock_policy_rwsem(write, cpu);
#define unlock_policy_rwsem(mode, cpu) \
static void unlock_policy_rwsem_##mode(int cpu) \
{ \
int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
BUG_ON(policy_cpu == -1); \
up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
}
unlock_policy_rwsem(read, cpu);
unlock_policy_rwsem(write, cpu);
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy,
unsigned int event);
static unsigned int __cpufreq_get(unsigned int cpu);
static void handle_update(struct work_struct *work);
/**
* 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);
static struct srcu_notifier_head cpufreq_transition_notifier_list;
static bool init_cpufreq_transition_notifier_list_called;
static int __init init_cpufreq_transition_notifier_list(void)
{
srcu_init_notifier_head(&cpufreq_transition_notifier_list);
init_cpufreq_transition_notifier_list_called = true;
return 0;
}
pure_initcall(init_cpufreq_transition_notifier_list);
static int off __read_mostly;
static int cpufreq_disabled(void)
{
return off;
}
void disable_cpufreq(void)
{
off = 1;
}
static LIST_HEAD(cpufreq_governor_list);
static DEFINE_MUTEX(cpufreq_governor_mutex);
bool have_governor_per_policy(void)
{
return cpufreq_driver->have_governor_per_policy;
}
EXPORT_SYMBOL_GPL(have_governor_per_policy);
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 struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
{
struct cpufreq_policy *data;
unsigned long flags;
if (cpu >= nr_cpu_ids)
goto err_out;
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);
if (!cpufreq_driver)
goto err_out_unlock;
if (!try_module_get(cpufreq_driver->owner))
goto err_out_unlock;
/* get the CPU */
data = per_cpu(cpufreq_cpu_data, cpu);
if (!data)
goto err_out_put_module;
if (!sysfs && !kobject_get(&data->kobj))
goto err_out_put_module;
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
return data;
err_out_put_module:
module_put(cpufreq_driver->owner);
err_out_unlock:
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
err_out:
return NULL;
}
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
if (cpufreq_disabled())
return NULL;
return __cpufreq_cpu_get(cpu, false);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu)
{
return __cpufreq_cpu_get(cpu, true);
}
static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs)
{
if (!sysfs)
kobject_put(&data->kobj);
module_put(cpufreq_driver->owner);
}
void cpufreq_cpu_put(struct cpufreq_policy *data)
{
if (cpufreq_disabled())
return;
__cpufreq_cpu_put(data, false);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data)
{
__cpufreq_cpu_put(data, true);
}
/*********************************************************************
* EXTERNALLY AFFECTING FREQUENCY CHANGES *
*********************************************************************/
/**
* adjust_jiffies - adjust the system "loops_per_jiffy"
*
* 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.
*/
#ifndef CONFIG_SMP
static unsigned long l_p_j_ref;
static unsigned int l_p_j_ref_freq;
static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
{
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) ||
(val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
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);
}
}
#else
static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
{
return;
}
#endif
void __cpufreq_notify_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, unsigned int state)
{
BUG_ON(irqs_disabled());
if (cpufreq_disabled())
return;
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 (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
if ((policy) && (policy->cpu == freqs->cpu) &&
(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: %lu - CPU: %lu", (unsigned long)freqs->new,
(unsigned long)freqs->cpu);
trace_cpu_frequency(freqs->new, freqs->cpu);
srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
CPUFREQ_POSTCHANGE, freqs);
if (likely(policy) && likely(policy->cpu == freqs->cpu))
policy->cur = freqs->new;
break;
}
}
/**
* cpufreq_notify_transition - call notifier chain and adjust_jiffies
* on frequency transition.
*
* This function calls the transition notifiers and the "adjust_jiffies"
* function. It is called twice on all CPU frequency changes that have
* external effects.
*/
void cpufreq_notify_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, unsigned int state)
{
for_each_cpu(freqs->cpu, policy->cpus)
__cpufreq_notify_transition(policy, freqs, state);
}
EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
/*********************************************************************
* SYSFS INTERFACE *
*********************************************************************/
static struct cpufreq_governor *__find_governor(const char *str_governor)
{
struct cpufreq_governor *t;
list_for_each_entry(t, &cpufreq_governor_list, governor_list)
if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
return t;
return NULL;
}
/**
* cpufreq_parse_governor - parse a governor string
*/
static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
struct cpufreq_governor **governor)
{
int err = -EINVAL;
if (!cpufreq_driver)
goto out;
if (cpufreq_driver->setpolicy) {
if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
*policy = CPUFREQ_POLICY_PERFORMANCE;
err = 0;
} else if (!strnicmp(str_governor, "powersave",
CPUFREQ_NAME_LEN)) {
*policy = CPUFREQ_POLICY_POWERSAVE;
err = 0;
}
} else if (cpufreq_driver->target) {
struct cpufreq_governor *t;
mutex_lock(&cpufreq_governor_mutex);
t = __find_governor(str_governor);
if (t == NULL) {
int ret;
mutex_unlock(&cpufreq_governor_mutex);
ret = request_module("cpufreq_%s", str_governor);
mutex_lock(&cpufreq_governor_mutex);
if (ret == 0)
t = __find_governor(str_governor);
}
if (t != NULL) {
*governor = t;
err = 0;
}
mutex_unlock(&cpufreq_governor_mutex);
}
out:
return err;
}
/**
* 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);
show_one(scaling_cur_freq, cur);
static int __cpufreq_set_policy(struct cpufreq_policy *data,
struct cpufreq_policy *policy);
/**
* 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 int ret; \
struct cpufreq_policy new_policy; \
\
ret = cpufreq_get_policy(&new_policy, policy->cpu); \
if (ret) \
return -EINVAL; \
\
ret = sscanf(buf, "%u", &new_policy.object); \
if (ret != 1) \
return -EINVAL; \
\
ret = __cpufreq_set_policy(policy, &new_policy); \
policy->user_policy.object = policy->object; \
\
return ret ? ret : count; \
}
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->cpu);
if (!cur_freq)
return sprintf(buf, "<unknown>");
return sprintf(buf, "%u\n", cur_freq);
}
/**
* 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)
{
unsigned int ret;
char str_governor[16];
struct cpufreq_policy new_policy;
ret = cpufreq_get_policy(&new_policy, policy->cpu);
if (ret)
return ret;
ret = sscanf(buf, "%15s", str_governor);
if (ret != 1)
return -EINVAL;
if (cpufreq_parse_governor(str_governor, &new_policy.policy,
&new_policy.governor))
return -EINVAL;
/* Do not use cpufreq_set_policy here or the user_policy.max
will be wrongly overridden */
ret = __cpufreq_set_policy(policy, &new_policy);
policy->user_policy.policy = policy->policy;
policy->user_policy.governor = policy->governor;
if (ret)
return ret;
else
return 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 (!cpufreq_driver->target) {
i += sprintf(buf, "performance powersave");
goto out;
}
list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
- (CPUFREQ_NAME_LEN + 2)))
goto out;
i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
}
out:
i += sprintf(&buf[i], "\n");
return i;
}
static ssize_t show_cpus(const struct cpumask *mask, char *buf)
{
ssize_t i = 0;
unsigned int cpu;
for_each_cpu(cpu, mask) {
if (i)
i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
if (i >= (PAGE_SIZE - 5))
break;
}
i += sprintf(&buf[i], "\n");
return i;
}
/**
* 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 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 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;
if (cpufreq_driver->bios_limit) {
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 *default_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
};
struct kobject *cpufreq_global_kobject;
EXPORT_SYMBOL(cpufreq_global_kobject);
#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 = -EINVAL;
policy = cpufreq_cpu_get_sysfs(policy->cpu);
if (!policy)
goto no_policy;
if (lock_policy_rwsem_read(policy->cpu) < 0)
goto fail;
if (fattr->show)
ret = fattr->show(policy, buf);
else
ret = -EIO;
unlock_policy_rwsem_read(policy->cpu);
fail:
cpufreq_cpu_put_sysfs(policy);
no_policy:
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 = -EINVAL;
policy = cpufreq_cpu_get_sysfs(policy->cpu);
if (!policy)
goto no_policy;
if (lock_policy_rwsem_write(policy->cpu) < 0)
goto fail;
if (fattr->store)
ret = fattr->store(policy, buf, count);
else
ret = -EIO;
unlock_policy_rwsem_write(policy->cpu);
fail:
cpufreq_cpu_put_sysfs(policy);
no_policy:
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_attrs = default_attrs,
.release = cpufreq_sysfs_release,
};
/* symlink affected CPUs */
static int cpufreq_add_dev_symlink(unsigned int cpu,
struct cpufreq_policy *policy)
{
unsigned int j;
int ret = 0;
for_each_cpu(j, policy->cpus) {
struct cpufreq_policy *managed_policy;
struct device *cpu_dev;
if (j == cpu)
continue;
pr_debug("CPU %u already managed, adding link\n", j);
managed_policy = cpufreq_cpu_get(cpu);
cpu_dev = get_cpu_device(j);
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
"cpufreq");
if (ret) {
cpufreq_cpu_put(managed_policy);
return ret;
}
}
return ret;
}
static int cpufreq_add_dev_interface(unsigned int cpu,
struct cpufreq_policy *policy,
struct device *dev)
{
struct cpufreq_policy new_policy;
struct freq_attr **drv_attr;
unsigned long flags;
int ret = 0;
unsigned int j;
/* prepare interface data */
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
&dev->kobj, "cpufreq");
if (ret)
return ret;
/* 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)
goto err_out_kobj_put;
drv_attr++;
}
if (cpufreq_driver->get) {
ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
if (ret)
goto err_out_kobj_put;
}
if (cpufreq_driver->target) {
ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
if (ret)
goto err_out_kobj_put;
}
if (cpufreq_driver->bios_limit) {
ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
if (ret)
goto err_out_kobj_put;
}
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
}
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
ret = cpufreq_add_dev_symlink(cpu, policy);
if (ret)
goto err_out_kobj_put;
memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
/* assure that the starting sequence is run in __cpufreq_set_policy */
policy->governor = NULL;
/* set default policy */
ret = __cpufreq_set_policy(policy, &new_policy);
policy->user_policy.policy = policy->policy;
policy->user_policy.governor = policy->governor;
if (ret) {
pr_debug("setting policy failed\n");
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
}
return ret;
err_out_kobj_put:
kobject_put(&policy->kobj);
wait_for_completion(&policy->kobj_unregister);
return ret;
}
#ifdef CONFIG_HOTPLUG_CPU
static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
struct device *dev)
{
struct cpufreq_policy *policy;
int ret = 0, has_target = !!cpufreq_driver->target;
unsigned long flags;
policy = cpufreq_cpu_get(sibling);
WARN_ON(!policy);
if (has_target)
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
lock_policy_rwsem_write(sibling);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpumask_set_cpu(cpu, policy->cpus);
per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu;
per_cpu(cpufreq_cpu_data, cpu) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
unlock_policy_rwsem_write(sibling);
if (has_target) {
__cpufreq_governor(policy, CPUFREQ_GOV_START);
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}
ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
if (ret) {
cpufreq_cpu_put(policy);
return ret;
}
return 0;
}
#endif
/**
* cpufreq_add_dev - add a CPU device
*
* Adds the cpufreq interface for a CPU device.
*
* The Oracle says: try running cpufreq registration/unregistration concurrently
* with with cpu hotplugging and all hell will break loose. Tried to clean this
* mess up, but more thorough testing is needed. - Mathieu
*/
static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int j, cpu = dev->id;
int ret = -ENOMEM;
struct cpufreq_policy *policy;
unsigned long flags;
#ifdef CONFIG_HOTPLUG_CPU
struct cpufreq_governor *gov;
int sibling;
#endif
if (cpu_is_offline(cpu))
return 0;
pr_debug("adding CPU %u\n", cpu);
#ifdef CONFIG_SMP
/* check whether a different CPU already registered this
* CPU because it is in the same boat. */
policy = cpufreq_cpu_get(cpu);
if (unlikely(policy)) {
cpufreq_cpu_put(policy);
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
/* Check if this cpu was hot-unplugged earlier and has siblings */
read_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_online_cpu(sibling) {
struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
return cpufreq_add_policy_cpu(cpu, sibling, dev);
}
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
#endif
#endif
if (!try_module_get(cpufreq_driver->owner)) {
ret = -EINVAL;
goto module_out;
}
policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
if (!policy)
goto nomem_out;
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;
policy->cpu = cpu;
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
cpumask_copy(policy->cpus, cpumask_of(cpu));
/* Initially set CPU itself as the policy_cpu */
per_cpu(cpufreq_policy_cpu, cpu) = cpu;
init_completion(&policy->kobj_unregister);
INIT_WORK(&policy->update, handle_update);
/* 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("initialization failed\n");
goto err_set_policy_cpu;
}
/* related cpus should atleast have policy->cpus */
cpumask_or(policy->related_cpus, 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);
policy->user_policy.min = policy->min;
policy->user_policy.max = policy->max;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
#ifdef CONFIG_HOTPLUG_CPU
gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
if (gov) {
policy->governor = gov;
pr_debug("Restoring governor %s for cpu %d\n",
policy->governor->name, cpu);
}
#endif
ret = cpufreq_add_dev_interface(cpu, policy, dev);
if (ret)
goto err_out_unregister;
kobject_uevent(&policy->kobj, KOBJ_ADD);
module_put(cpufreq_driver->owner);
pr_debug("initialization complete\n");
return 0;
err_out_unregister:
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
kobject_put(&policy->kobj);
wait_for_completion(&policy->kobj_unregister);
err_set_policy_cpu:
per_cpu(cpufreq_policy_cpu, cpu) = -1;
free_cpumask_var(policy->related_cpus);
err_free_cpumask:
free_cpumask_var(policy->cpus);
err_free_policy:
kfree(policy);
nomem_out:
module_put(cpufreq_driver->owner);
module_out:
return ret;
}
static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
int j;
policy->last_cpu = policy->cpu;
policy->cpu = cpu;
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_policy_cpu, j) = cpu;
#ifdef CONFIG_CPU_FREQ_TABLE
cpufreq_frequency_table_update_policy_cpu(policy);
#endif
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_UPDATE_POLICY_CPU, policy);
}
/**
* __cpufreq_remove_dev - remove a CPU device
*
* Removes the cpufreq interface for a CPU device.
* Caller should already have policy_rwsem in write mode for this CPU.
* This routine frees the rwsem before returning.
*/
static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id, ret, cpus;
unsigned long flags;
struct cpufreq_policy *data;
struct kobject *kobj;
struct completion *cmp;
struct device *cpu_dev;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
write_lock_irqsave(&cpufreq_driver_lock, flags);
data = per_cpu(cpufreq_cpu_data, cpu);
per_cpu(cpufreq_cpu_data, cpu) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!data) {
pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL;
}
if (cpufreq_driver->target)
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
#ifdef CONFIG_HOTPLUG_CPU
if (!cpufreq_driver->setpolicy)
strncpy(per_cpu(cpufreq_cpu_governor, cpu),
data->governor->name, CPUFREQ_NAME_LEN);
#endif
WARN_ON(lock_policy_rwsem_write(cpu));
cpus = cpumask_weight(data->cpus);
if (cpus > 1)
cpumask_clear_cpu(cpu, data->cpus);
unlock_policy_rwsem_write(cpu);
if (cpu != data->cpu) {
sysfs_remove_link(&dev->kobj, "cpufreq");
} else if (cpus > 1) {
/* first sibling now owns the new sysfs dir */
cpu_dev = get_cpu_device(cpumask_first(data->cpus));
sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
ret = kobject_move(&data->kobj, &cpu_dev->kobj);
if (ret) {
pr_err("%s: Failed to move kobj: %d", __func__, ret);
WARN_ON(lock_policy_rwsem_write(cpu));
cpumask_set_cpu(cpu, data->cpus);
write_lock_irqsave(&cpufreq_driver_lock, flags);
per_cpu(cpufreq_cpu_data, cpu) = data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
unlock_policy_rwsem_write(cpu);
ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
"cpufreq");
return -EINVAL;
}
WARN_ON(lock_policy_rwsem_write(cpu));
update_policy_cpu(data, cpu_dev->id);
unlock_policy_rwsem_write(cpu);
pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
__func__, cpu_dev->id, cpu);
}
if ((cpus == 1) && (cpufreq_driver->target))
__cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
cpufreq_cpu_put(data);
/* If cpu is last user of policy, free policy */
if (cpus == 1) {
lock_policy_rwsem_read(cpu);
kobj = &data->kobj;
cmp = &data->kobj_unregister;
unlock_policy_rwsem_read(cpu);
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");
if (cpufreq_driver->exit)
cpufreq_driver->exit(data);
free_cpumask_var(data->related_cpus);
free_cpumask_var(data->cpus);
kfree(data);
} else if (cpufreq_driver->target) {
__cpufreq_governor(data, CPUFREQ_GOV_START);
__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
}
per_cpu(cpufreq_policy_cpu, cpu) = -1;
return 0;
}
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
int retval;
if (cpu_is_offline(cpu))
return 0;
retval = __cpufreq_remove_dev(dev, sif);
return retval;
}
static void handle_update(struct work_struct *work)
{
struct cpufreq_policy *policy =
container_of(work, struct cpufreq_policy, update);
unsigned int cpu = policy->cpu;
pr_debug("handle_update for cpu %u called\n", cpu);
cpufreq_update_policy(cpu);
}
/**
* cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
* @cpu: cpu number
* @old_freq: CPU frequency the kernel thinks the CPU runs at
* @new_freq: CPU frequency the CPU actually runs at
*
* We adjust to current frequency first, and need to clean up later.
* So either call to cpufreq_update_policy() or schedule handle_update()).
*/
static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
unsigned int new_freq)
{
struct cpufreq_policy *policy;
struct cpufreq_freqs freqs;
unsigned long flags;
pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
"core thinks of %u, is %u kHz.\n", old_freq, new_freq);
freqs.old = old_freq;
freqs.new = new_freq;
read_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
}
/**
* 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;
if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
return cpufreq_driver->get(cpu);
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);
static unsigned int __cpufreq_get(unsigned int cpu)
{
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
unsigned int ret_freq = 0;
if (!cpufreq_driver->get)
return ret_freq;
ret_freq = cpufreq_driver->get(cpu);
if (ret_freq && policy->cur &&
!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
/* verify no discrepancy between actual and
saved value exists */
if (unlikely(ret_freq != policy->cur)) {
cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
schedule_work(&policy->update);
}
}
return ret_freq;
}
/**
* 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)
{
unsigned int ret_freq = 0;
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
if (!policy)
goto out;
if (unlikely(lock_policy_rwsem_read(cpu)))
goto out_policy;
ret_freq = __cpufreq_get(cpu);
unlock_policy_rwsem_read(cpu);
out_policy:
cpufreq_cpu_put(policy);
out:
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,
};
/**
* cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
*
* This function is only executed for the boot processor. The other CPUs
* have been put offline by means of CPU hotplug.
*/
static int cpufreq_bp_suspend(void)
{
int ret = 0;
int cpu = smp_processor_id();
struct cpufreq_policy *cpu_policy;
pr_debug("suspending cpu %u\n", cpu);
/* If there's no policy for the boot CPU, we have nothing to do. */
cpu_policy = cpufreq_cpu_get(cpu);
if (!cpu_policy)
return 0;
if (cpufreq_driver->suspend) {
ret = cpufreq_driver->suspend(cpu_policy);
if (ret)
printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
"step on CPU %u\n", cpu_policy->cpu);
}
cpufreq_cpu_put(cpu_policy);
return ret;
}
/**
* cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
*
* 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
* 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
* restored. It will verify that the current freq is in sync with
* what we believe it to be. This is a bit later than when it
* should be, but nonethteless it's better than calling
* cpufreq_driver->get() here which might re-enable interrupts...
*
* This function is only executed for the boot CPU. The other CPUs have not
* been turned on yet.
*/
static void cpufreq_bp_resume(void)
{
int ret = 0;
int cpu = smp_processor_id();
struct cpufreq_policy *cpu_policy;
pr_debug("resuming cpu %u\n", cpu);
/* If there's no policy for the boot CPU, we have nothing to do. */
cpu_policy = cpufreq_cpu_get(cpu);
if (!cpu_policy)
return;
if (cpufreq_driver->resume) {
ret = cpufreq_driver->resume(cpu_policy);
if (ret) {
printk(KERN_ERR "cpufreq: resume failed in ->resume "
"step on CPU %u\n", cpu_policy->cpu);
goto fail;
}
}
schedule_work(&cpu_policy->update);
fail:
cpufreq_cpu_put(cpu_policy);
}
static struct syscore_ops cpufreq_syscore_ops = {
.suspend = cpufreq_bp_suspend,
.resume = cpufreq_bp_resume,
};
/**
* cpufreq_get_current_driver - return current driver's name
*
* Return the name string of the currently loaded 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);
/*********************************************************************
* NOTIFIER LISTS INTERFACE *
*********************************************************************/
/**
* cpufreq_register_notifier - register a driver with cpufreq
* @nb: notifier function to register
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
*
* Add a driver to one of two lists: either a list of drivers that
* are notified about clock rate changes (once before and once after
* the transition), or a list of drivers that are notified about
* changes in cpufreq policy.
*
* This function may sleep, and has the same return conditions as
* blocking_notifier_chain_register.
*/
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
{
int ret;
if (cpufreq_disabled())
return -EINVAL;
WARN_ON(!init_cpufreq_transition_notifier_list_called);
switch (list) {
case CPUFREQ_TRANSITION_NOTIFIER:
ret = srcu_notifier_chain_register(
&cpufreq_transition_notifier_list, nb);
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 driver with cpufreq
* @nb: notifier block to be unregistered
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
*
* Remove a driver from the CPU frequency notifier list.
*
* This function may sleep, and has the same return conditions 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:
ret = srcu_notifier_chain_unregister(
&cpufreq_transition_notifier_list, nb);
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 *
*********************************************************************/
int __cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
int retval = -EINVAL;
unsigned int old_target_freq = target_freq;
if (cpufreq_disabled())
return -ENODEV;
/* Make sure that target_freq is within supported range */
if (target_freq > policy->max)
target_freq = policy->max;
if (target_freq < policy->min)
target_freq = policy->min;
pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
policy->cpu, target_freq, relation, old_target_freq);
if (target_freq == policy->cur)
return 0;
if (cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);
return retval;
}
EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
int cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
int ret = -EINVAL;
policy = cpufreq_cpu_get(policy->cpu);
if (!policy)
goto no_policy;
if (unlikely(lock_policy_rwsem_write(policy->cpu)))
goto fail;
ret = __cpufreq_driver_target(policy, target_freq, relation);
unlock_policy_rwsem_write(policy->cpu);
fail:
cpufreq_cpu_put(policy);
no_policy:
return ret;
}
EXPORT_SYMBOL_GPL(cpufreq_driver_target);
int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
{
int ret = 0;
if (cpufreq_disabled())
return ret;
if (!cpufreq_driver->getavg)
return 0;
policy = cpufreq_cpu_get(policy->cpu);
if (!policy)
return -EINVAL;
ret = cpufreq_driver->getavg(policy, cpu);
cpufreq_cpu_put(policy);
return ret;
}
EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
/*
* when "event" is CPUFREQ_GOV_LIMITS
*/
static int __cpufreq_governor(struct cpufreq_policy *policy,
unsigned int event)
{
int ret;
/* Only must be defined when default governor is known to have latency
restrictions, like e.g. conservative or ondemand.
That this is the case is already ensured in Kconfig
*/
#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
struct cpufreq_governor *gov = &cpufreq_gov_performance;
#else
struct cpufreq_governor *gov = NULL;
#endif
if (policy->governor->max_transition_latency &&
policy->cpuinfo.transition_latency >
policy->governor->max_transition_latency) {
if (!gov)
return -EINVAL;
else {
printk(KERN_WARNING "%s governor failed, too long"
" transition latency of HW, fallback"
" to %s governor\n",
policy->governor->name,
gov->name);
policy->governor = gov;
}
}
if (!try_module_get(policy->governor->owner))
return -EINVAL;
pr_debug("__cpufreq_governor for CPU %u, event %u\n",
policy->cpu, event);
ret = policy->governor->governor(policy, event);
if (!ret) {
if (event == CPUFREQ_GOV_POLICY_INIT)
policy->governor->initialized++;
else if (event == CPUFREQ_GOV_POLICY_EXIT)
policy->governor->initialized--;
}
/* we keep one module reference alive for
each CPU governed by this CPU */
if ((event != CPUFREQ_GOV_START) || ret)
module_put(policy->governor->owner);
if ((event == CPUFREQ_GOV_STOP) && !ret)
module_put(policy->governor->owner);
return ret;
}
int cpufreq_register_governor(struct cpufreq_governor *governor)
{
int err;
if (!governor)
return -EINVAL;
if (cpufreq_disabled())
return -ENODEV;
mutex_lock(&cpufreq_governor_mutex);
governor->initialized = 0;
err = -EBUSY;
if (__find_governor(governor->name) == NULL) {
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)
{
#ifdef CONFIG_HOTPLUG_CPU
int cpu;
#endif
if (!governor)
return;
if (cpufreq_disabled())
return;
#ifdef CONFIG_HOTPLUG_CPU
for_each_present_cpu(cpu) {
if (cpu_online(cpu))
continue;
if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
}
#endif
mutex_lock(&cpufreq_governor_mutex);
list_del(&governor->governor_list);
mutex_unlock(&cpufreq_governor_mutex);
return;
}
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
*
* 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(struct cpufreq_policy));
cpufreq_cpu_put(cpu_policy);
return 0;
}
EXPORT_SYMBOL(cpufreq_get_policy);
/*
* data : current policy.
* policy : policy to be set.
*/
static int __cpufreq_set_policy(struct cpufreq_policy *data,
struct cpufreq_policy *policy)
{
int ret = 0, failed = 1;
pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
policy->min, policy->max);
memcpy(&policy->cpuinfo, &data->cpuinfo,
sizeof(struct cpufreq_cpuinfo));
if (policy->min > data->max || policy->max < data->min) {
ret = -EINVAL;
goto error_out;
}
/* verify the cpu speed can be set within this limit */
ret = cpufreq_driver->verify(policy);
if (ret)
goto error_out;
/* adjust if necessary - all reasons */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_ADJUST, policy);
/* adjust if necessary - hardware incompatibility*/
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_INCOMPATIBLE, policy);
/* verify the cpu speed can be set within this limit,
which might be different to the first one */
ret = cpufreq_driver->verify(policy);
if (ret)
goto error_out;
/* notification of the new policy */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_NOTIFY, policy);
data->min = policy->min;
data->max = policy->max;
trace_cpu_frequency_limits(policy->max, policy->min, policy->cpu);
pr_debug("new min and max freqs are %u - %u kHz\n",
data->min, data->max);
if (cpufreq_driver->setpolicy) {
data->policy = policy->policy;
pr_debug("setting range\n");
ret = cpufreq_driver->setpolicy(policy);
} else {
if (policy->governor != data->governor) {
/* save old, working values */
struct cpufreq_governor *old_gov = data->governor;
pr_debug("governor switch\n");
/* end old governor */
if (data->governor) {
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
unlock_policy_rwsem_write(policy->cpu);
__cpufreq_governor(data,
CPUFREQ_GOV_POLICY_EXIT);
lock_policy_rwsem_write(policy->cpu);
}
/* start new governor */
data->governor = policy->governor;
if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) {
if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) {
failed = 0;
} else {
unlock_policy_rwsem_write(policy->cpu);
__cpufreq_governor(data,
CPUFREQ_GOV_POLICY_EXIT);
lock_policy_rwsem_write(policy->cpu);
}
}
if (failed) {
/* new governor failed, so re-start old one */
pr_debug("starting governor %s failed\n",
data->governor->name);
if (old_gov) {
data->governor = old_gov;
__cpufreq_governor(data,
CPUFREQ_GOV_POLICY_INIT);
__cpufreq_governor(data,
CPUFREQ_GOV_START);
}
ret = -EINVAL;
goto error_out;
}
/* might be a policy change, too, so fall through */
}
pr_debug("governor: change or update limits\n");
__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
}
error_out:
return ret;
}
/**
* cpufreq_update_policy - re-evaluate an existing cpufreq policy
* @cpu: CPU which shall be re-evaluated
*
* Useful for policy notifiers which have different necessities
* at different times.
*/
int cpufreq_update_policy(unsigned int cpu)
{
struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
struct cpufreq_policy policy;
int ret;
if (!data) {
ret = -ENODEV;
goto no_policy;
}
if (unlikely(lock_policy_rwsem_write(cpu))) {
ret = -EINVAL;
goto fail;
}
pr_debug("updating policy for CPU %u\n", cpu);
memcpy(&policy, data, sizeof(struct cpufreq_policy));
policy.min = data->user_policy.min;
policy.max = data->user_policy.max;
policy.policy = data->user_policy.policy;
policy.governor = data->user_policy.governor;
/* BIOS might change freq behind our back
-> ask driver for current freq and notify governors about a change */
if (cpufreq_driver->get) {
policy.cur = cpufreq_driver->get(cpu);
if (!data->cur) {
pr_debug("Driver did not initialize current freq");
data->cur = policy.cur;
} else {
if (data->cur != policy.cur && cpufreq_driver->target)
cpufreq_out_of_sync(cpu, data->cur,
policy.cur);
}
}
ret = __cpufreq_set_policy(data, &policy);
unlock_policy_rwsem_write(cpu);
fail:
cpufreq_cpu_put(data);
no_policy:
return ret;
}
EXPORT_SYMBOL(cpufreq_update_policy);
static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct device *dev;
dev = get_cpu_device(cpu);
if (dev) {
switch (action) {
case CPU_ONLINE:
cpufreq_add_dev(dev, NULL);
break;
case CPU_DOWN_PREPARE:
case CPU_UP_CANCELED_FROZEN:
__cpufreq_remove_dev(dev, NULL);
break;
case CPU_DOWN_FAILED:
cpufreq_add_dev(dev, NULL);
break;
}
}
return NOTIFY_OK;
}
static struct notifier_block __refdata cpufreq_cpu_notifier = {
.notifier_call = cpufreq_cpu_callback,
};
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
*********************************************************************/
/**
* 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, -EBUSY 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;
if (!driver_data || !driver_data->verify || !driver_data->init ||
((!driver_data->setpolicy) && (!driver_data->target)))
return -EINVAL;
pr_debug("trying to register driver %s\n", driver_data->name);
if (driver_data->setpolicy)
driver_data->flags |= CPUFREQ_CONST_LOOPS;
write_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
return -EBUSY;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
ret = subsys_interface_register(&cpufreq_interface);
if (ret)
goto err_null_driver;
if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
int i;
ret = -ENODEV;
/* check for at least one working CPU */
for (i = 0; i < nr_cpu_ids; i++)
if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
ret = 0;
break;
}
/* if all ->init() calls failed, unregister */
if (ret) {
pr_debug("no CPU initialized for driver %s\n",
driver_data->name);
goto err_if_unreg;
}
}
register_hotcpu_notifier(&cpufreq_cpu_notifier);
pr_debug("driver %s up and running\n", driver_data->name);
return 0;
err_if_unreg:
subsys_interface_unregister(&cpufreq_interface);
err_null_driver:
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
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);
subsys_interface_unregister(&cpufreq_interface);
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
static int __init cpufreq_core_init(void)
{
int cpu;
if (cpufreq_disabled())
return -ENODEV;
for_each_possible_cpu(cpu) {
per_cpu(cpufreq_policy_cpu, cpu) = -1;
init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
}
cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
BUG_ON(!cpufreq_global_kobject);
register_syscore_ops(&cpufreq_syscore_ops);
return 0;
}
core_initcall(cpufreq_core_init);