linux/drivers/cpufreq/cpufreq.c
Viresh Kumar 1c03a2d04d cpufreq: add support for intermediate (stable) frequencies
Douglas Anderson, recently pointed out an interesting problem due to which
udelay() was expiring earlier than it should.

While transitioning between frequencies few platforms may temporarily switch to
a stable frequency, waiting for the main PLL to stabilize.

For example: When we transition between very low frequencies on exynos, like
between 200MHz and 300MHz, we may temporarily switch to a PLL running at 800MHz.
No CPUFREQ notification is sent for that. That means there's a period of time
when we're running at 800MHz but loops_per_jiffy is calibrated at between 200MHz
and 300MHz. And so udelay behaves badly.

To get this fixed in a generic way, introduce another set of callbacks
get_intermediate() and target_intermediate(), only for drivers with
target_index() and CPUFREQ_ASYNC_NOTIFICATION unset.

get_intermediate() should return a stable intermediate frequency platform wants
to switch to, and target_intermediate() should set CPU to that frequency,
before jumping to the frequency corresponding to 'index'. Core will take care of
sending notifications and driver doesn't have to handle them in
target_intermediate() or target_index().

NOTE: ->target_index() should restore to policy->restore_freq in case of
failures as core would send notifications for that.

Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-05 23:32:29 +02:00

2535 lines
64 KiB
C

/*
* 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
*
* 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/cpu.h>
#include <linux/cpufreq.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/slab.h>
#include <linux/suspend.h>
#include <linux/tick.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);
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
static DEFINE_RWLOCK(cpufreq_driver_lock);
DEFINE_MUTEX(cpufreq_governor_lock);
static LIST_HEAD(cpufreq_policy_list);
/* This one keeps track of the previously set governor of a removed CPU */
static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
/* Flag to suspend/resume CPUFreq governors */
static bool cpufreq_suspended;
static inline bool has_target(void)
{
return cpufreq_driver->target_index || cpufreq_driver->target;
}
/*
* rwsem to guarantee that cpufreq driver module doesn't unload during critical
* sections
*/
static DECLARE_RWSEM(cpufreq_rwsem);
/* 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->flags & CPUFREQ_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 inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
u64 idle_time;
u64 cur_wall_time;
u64 busy_time;
cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
idle_time = cur_wall_time - busy_time;
if (wall)
*wall = cputime_to_usecs(cur_wall_time);
return cputime_to_usecs(idle_time);
}
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
*/
int cpufreq_generic_init(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table,
unsigned int transition_latency)
{
int ret;
ret = cpufreq_table_validate_and_show(policy, table);
if (ret) {
pr_err("%s: invalid frequency table: %d\n", __func__, ret);
return ret;
}
policy->cpuinfo.transition_latency = transition_latency;
/*
* The driver only supports the SMP configuartion where all processors
* share the clock and voltage and clock.
*/
cpumask_setall(policy->cpus);
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_generic_init);
unsigned int cpufreq_generic_get(unsigned int cpu)
{
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, 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);
/* Only for cpufreq core internal use */
struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
{
return per_cpu(cpufreq_cpu_data, cpu);
}
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
struct cpufreq_policy *policy = NULL;
unsigned long flags;
if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
return NULL;
if (!down_read_trylock(&cpufreq_rwsem))
return NULL;
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
/* get the CPU */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy)
kobject_get(&policy->kobj);
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!policy)
up_read(&cpufreq_rwsem);
return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
if (cpufreq_disabled())
return;
kobject_put(&policy->kobj);
up_read(&cpufreq_rwsem);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
/*********************************************************************
* 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) {
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
static 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\n",
(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.
*/
static 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);
}
/* 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 (unlikely(WARN_ON(!policy->transition_ongoing)))
return;
cpufreq_notify_post_transition(policy, freqs, transition_failed);
policy->transition_ongoing = false;
policy->transition_task = NULL;
wake_up(&policy->transition_wait);
}
EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
/*********************************************************************
* SYSFS INTERFACE *
*********************************************************************/
static ssize_t show_boost(struct kobject *kobj,
struct attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
}
static ssize_t store_boost(struct kobject *kobj, struct 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;
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 (has_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 *policy,
struct cpufreq_policy *new_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) \
{ \
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)
{
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;
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 (!has_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;
}
ssize_t cpufreq_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;
}
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;
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
};
#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;
if (!down_read_trylock(&cpufreq_rwsem))
return -EINVAL;
down_read(&policy->rwsem);
if (fattr->show)
ret = fattr->show(policy, buf);
else
ret = -EIO;
up_read(&policy->rwsem);
up_read(&cpufreq_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 = -EINVAL;
get_online_cpus();
if (!cpu_online(policy->cpu))
goto unlock;
if (!down_read_trylock(&cpufreq_rwsem))
goto unlock;
down_write(&policy->rwsem);
if (fattr->store)
ret = fattr->store(policy, buf, count);
else
ret = -EIO;
up_write(&policy->rwsem);
up_read(&cpufreq_rwsem);
unlock:
put_online_cpus();
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,
};
struct kobject *cpufreq_global_kobject;
EXPORT_SYMBOL(cpufreq_global_kobject);
static int cpufreq_global_kobject_usage;
int cpufreq_get_global_kobject(void)
{
if (!cpufreq_global_kobject_usage++)
return kobject_add(cpufreq_global_kobject,
&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
return 0;
}
EXPORT_SYMBOL(cpufreq_get_global_kobject);
void cpufreq_put_global_kobject(void)
{
if (!--cpufreq_global_kobject_usage)
kobject_del(cpufreq_global_kobject);
}
EXPORT_SYMBOL(cpufreq_put_global_kobject);
int cpufreq_sysfs_create_file(const struct attribute *attr)
{
int ret = cpufreq_get_global_kobject();
if (!ret) {
ret = sysfs_create_file(cpufreq_global_kobject, attr);
if (ret)
cpufreq_put_global_kobject();
}
return ret;
}
EXPORT_SYMBOL(cpufreq_sysfs_create_file);
void cpufreq_sysfs_remove_file(const struct attribute *attr)
{
sysfs_remove_file(cpufreq_global_kobject, attr);
cpufreq_put_global_kobject();
}
EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
/* symlink affected CPUs */
static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
{
unsigned int j;
int ret = 0;
for_each_cpu(j, policy->cpus) {
struct device *cpu_dev;
if (j == policy->cpu)
continue;
pr_debug("Adding link for CPU: %u\n", j);
cpu_dev = get_cpu_device(j);
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
"cpufreq");
if (ret)
break;
}
return ret;
}
static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
struct device *dev)
{
struct freq_attr **drv_attr;
int ret = 0;
/* 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 (has_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;
}
ret = cpufreq_add_dev_symlink(policy);
if (ret)
goto err_out_kobj_put;
return ret;
err_out_kobj_put:
kobject_put(&policy->kobj);
wait_for_completion(&policy->kobj_unregister);
return ret;
}
static void cpufreq_init_policy(struct cpufreq_policy *policy)
{
struct cpufreq_governor *gov = NULL;
struct cpufreq_policy new_policy;
int ret = 0;
memcpy(&new_policy, policy, sizeof(*policy));
/* Update governor of new_policy to the governor used before hotplug */
gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
if (gov)
pr_debug("Restoring governor %s for cpu %d\n",
policy->governor->name, policy->cpu);
else
gov = CPUFREQ_DEFAULT_GOVERNOR;
new_policy.governor = gov;
/* Use the default policy if its valid. */
if (cpufreq_driver->setpolicy)
cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
/* set default policy */
ret = cpufreq_set_policy(policy, &new_policy);
if (ret) {
pr_debug("setting policy failed\n");
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
}
}
#ifdef CONFIG_HOTPLUG_CPU
static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
unsigned int cpu, struct device *dev)
{
int ret = 0;
unsigned long flags;
if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
if (ret) {
pr_err("%s: Failed to stop governor\n", __func__);
return ret;
}
}
down_write(&policy->rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpumask_set_cpu(cpu, policy->cpus);
per_cpu(cpufreq_cpu_data, cpu) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
up_write(&policy->rwsem);
if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
if (!ret)
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
if (ret) {
pr_err("%s: Failed to start governor\n", __func__);
return ret;
}
}
return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
}
#endif
static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
{
struct cpufreq_policy *policy;
unsigned long flags;
read_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
policy->governor = NULL;
return policy;
}
static struct cpufreq_policy *cpufreq_policy_alloc(void)
{
struct cpufreq_policy *policy;
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;
INIT_LIST_HEAD(&policy->policy_list);
init_rwsem(&policy->rwsem);
spin_lock_init(&policy->transition_lock);
init_waitqueue_head(&policy->transition_wait);
return policy;
err_free_cpumask:
free_cpumask_var(policy->cpus);
err_free_policy:
kfree(policy);
return NULL;
}
static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
{
struct kobject *kobj;
struct completion *cmp;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_REMOVE_POLICY, policy);
down_read(&policy->rwsem);
kobj = &policy->kobj;
cmp = &policy->kobj_unregister;
up_read(&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 void cpufreq_policy_free(struct cpufreq_policy *policy)
{
free_cpumask_var(policy->related_cpus);
free_cpumask_var(policy->cpus);
kfree(policy);
}
static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
if (WARN_ON(cpu == policy->cpu))
return;
down_write(&policy->rwsem);
policy->last_cpu = policy->cpu;
policy->cpu = cpu;
up_write(&policy->rwsem);
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_UPDATE_POLICY_CPU, policy);
}
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;
bool recover_policy = cpufreq_suspended;
#ifdef CONFIG_HOTPLUG_CPU
struct cpufreq_policy *tpolicy;
#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;
}
#endif
if (!down_read_trylock(&cpufreq_rwsem))
return 0;
#ifdef CONFIG_HOTPLUG_CPU
/* Check if this cpu was hot-unplugged earlier and has siblings */
read_lock_irqsave(&cpufreq_driver_lock, flags);
list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
up_read(&cpufreq_rwsem);
return ret;
}
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
#endif
/*
* Restore the saved policy when doing light-weight init and fall back
* to the full init if that fails.
*/
policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
if (!policy) {
recover_policy = false;
policy = cpufreq_policy_alloc();
if (!policy)
goto nomem_out;
}
/*
* In the resume path, since we restore a saved policy, the assignment
* to policy->cpu is like an update of the existing policy, rather than
* the creation of a brand new one. So we need to perform this update
* by invoking update_policy_cpu().
*/
if (recover_policy && cpu != policy->cpu)
update_policy_cpu(policy, cpu);
else
policy->cpu = cpu;
cpumask_copy(policy->cpus, cpumask_of(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);
if (!recover_policy) {
policy->user_policy.min = policy->min;
policy->user_policy.max = policy->max;
}
down_write(&policy->rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
policy->cur = cpufreq_driver->get(policy->cpu);
if (!policy->cur) {
pr_err("%s: ->get() failed\n", __func__);
goto err_get_freq;
}
}
/*
* 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()) {
/* Are we running at unknown frequency ? */
ret = cpufreq_frequency_table_get_index(policy, policy->cur);
if (ret == -EINVAL) {
/* Warn user and fix it */
pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
__func__, policy->cpu, policy->cur);
ret = __cpufreq_driver_target(policy, policy->cur - 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_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
__func__, policy->cpu, policy->cur);
}
}
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
if (!recover_policy) {
ret = cpufreq_add_dev_interface(policy, dev);
if (ret)
goto err_out_unregister;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
}
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_add(&policy->policy_list, &cpufreq_policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
cpufreq_init_policy(policy);
if (!recover_policy) {
policy->user_policy.policy = policy->policy;
policy->user_policy.governor = policy->governor;
}
up_write(&policy->rwsem);
kobject_uevent(&policy->kobj, KOBJ_ADD);
up_read(&cpufreq_rwsem);
pr_debug("initialization complete\n");
return 0;
err_out_unregister:
err_get_freq:
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);
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
err_set_policy_cpu:
if (recover_policy) {
/* Do not leave stale fallback data behind. */
per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
cpufreq_policy_put_kobj(policy);
}
cpufreq_policy_free(policy);
nomem_out:
up_read(&cpufreq_rwsem);
return ret;
}
/**
* 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)
{
return __cpufreq_add_dev(dev, sif);
}
static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
unsigned int old_cpu)
{
struct device *cpu_dev;
int ret;
/* first sibling now owns the new sysfs dir */
cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
if (ret) {
pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
down_write(&policy->rwsem);
cpumask_set_cpu(old_cpu, policy->cpus);
up_write(&policy->rwsem);
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
"cpufreq");
return -EINVAL;
}
return cpu_dev->id;
}
static int __cpufreq_remove_dev_prepare(struct device *dev,
struct subsys_interface *sif)
{
unsigned int cpu = dev->id, cpus;
int new_cpu, ret;
unsigned long flags;
struct cpufreq_policy *policy;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
write_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
/* Save the policy somewhere when doing a light-weight tear-down */
if (cpufreq_suspended)
per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL;
}
if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
if (ret) {
pr_err("%s: Failed to stop governor\n", __func__);
return ret;
}
}
if (!cpufreq_driver->setpolicy)
strncpy(per_cpu(cpufreq_cpu_governor, cpu),
policy->governor->name, CPUFREQ_NAME_LEN);
down_read(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
up_read(&policy->rwsem);
if (cpu != policy->cpu) {
sysfs_remove_link(&dev->kobj, "cpufreq");
} else if (cpus > 1) {
new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
if (new_cpu >= 0) {
update_policy_cpu(policy, new_cpu);
if (!cpufreq_suspended)
pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
__func__, new_cpu, cpu);
}
} else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
cpufreq_driver->stop_cpu(policy);
}
return 0;
}
static int __cpufreq_remove_dev_finish(struct device *dev,
struct subsys_interface *sif)
{
unsigned int cpu = dev->id, cpus;
int ret;
unsigned long flags;
struct cpufreq_policy *policy;
read_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL;
}
down_write(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
if (cpus > 1)
cpumask_clear_cpu(cpu, policy->cpus);
up_write(&policy->rwsem);
/* If cpu is last user of policy, free policy */
if (cpus == 1) {
if (has_target()) {
ret = __cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT);
if (ret) {
pr_err("%s: Failed to exit governor\n",
__func__);
return ret;
}
}
if (!cpufreq_suspended)
cpufreq_policy_put_kobj(policy);
/*
* Perform the ->exit() even during light-weight tear-down,
* since this is a core component, and is essential for the
* subsequent light-weight ->init() to succeed.
*/
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
/* Remove policy from list of active policies */
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_del(&policy->policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!cpufreq_suspended)
cpufreq_policy_free(policy);
} else if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
if (!ret)
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
if (ret) {
pr_err("%s: Failed to start governor\n", __func__);
return ret;
}
}
per_cpu(cpufreq_cpu_data, cpu) = NULL;
return 0;
}
/**
* cpufreq_remove_dev - remove a CPU device
*
* Removes the cpufreq interface for a CPU device.
*/
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
int ret;
if (cpu_is_offline(cpu))
return 0;
ret = __cpufreq_remove_dev_prepare(dev, sif);
if (!ret)
ret = __cpufreq_remove_dev_finish(dev, sif);
return ret;
}
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_freq_transition_begin(policy, &freqs);
cpufreq_freq_transition_end(policy, &freqs, 0);
}
/**
* 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)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
unsigned int ret_freq = 0;
if (policy) {
down_read(&policy->rwsem);
ret_freq = __cpufreq_get(cpu);
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_err("%s: suspend_freq can't be zero\n", __func__);
return -EINVAL;
}
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())
return;
pr_debug("%s: Suspending Governors\n", __func__);
list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
pr_err("%s: Failed to stop governor for policy: %p\n",
__func__, policy);
else if (cpufreq_driver->suspend
&& cpufreq_driver->suspend(policy))
pr_err("%s: Failed to suspend driver: %p\n", __func__,
policy);
}
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;
if (!cpufreq_driver)
return;
if (!has_target())
return;
pr_debug("%s: Resuming Governors\n", __func__);
cpufreq_suspended = false;
list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
pr_err("%s: Failed to resume driver: %p\n", __func__,
policy);
else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
|| __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
pr_err("%s: Failed to start governor for policy: %p\n",
__func__, policy);
/*
* schedule call cpufreq_update_policy() for boot CPU, i.e. last
* policy in list. It will verify that the current freq is in
* sync with what we believe it to be.
*/
if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
schedule_work(&policy->update);
}
}
/**
* 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 *
*********************************************************************/
/* 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,
struct cpufreq_frequency_table *freq_table, int index)
{
struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
unsigned int intermediate_freq = 0;
int retval = -EINVAL;
bool notify;
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 = freq_table[index].frequency;
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 have't switched to intermediate freq at all.
*/
if (unlikely(retval && intermediate_freq)) {
freqs.old = intermediate_freq;
freqs.new = policy->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;
int retval = -EINVAL;
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);
/*
* 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)
return 0;
/* Save last value to restore later on errors */
policy->restore_freq = policy->cur;
if (cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);
else if (cpufreq_driver->target_index) {
struct cpufreq_frequency_table *freq_table;
int index;
freq_table = cpufreq_frequency_get_table(policy->cpu);
if (unlikely(!freq_table)) {
pr_err("%s: Unable to find freq_table\n", __func__);
goto out;
}
retval = cpufreq_frequency_table_target(policy, freq_table,
target_freq, relation, &index);
if (unlikely(retval)) {
pr_err("%s: Unable to find matching freq\n", __func__);
goto out;
}
if (freq_table[index].frequency == policy->cur) {
retval = 0;
goto out;
}
retval = __target_index(policy, freq_table, index);
}
out:
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;
down_write(&policy->rwsem);
ret = __cpufreq_driver_target(policy, target_freq, relation);
up_write(&policy->rwsem);
return ret;
}
EXPORT_SYMBOL_GPL(cpufreq_driver_target);
/*
* 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
/* Don't start any governor operations if we are entering suspend */
if (cpufreq_suspended)
return 0;
if (policy->governor->max_transition_latency &&
policy->cpuinfo.transition_latency >
policy->governor->max_transition_latency) {
if (!gov)
return -EINVAL;
else {
pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
policy->governor->name, gov->name);
policy->governor = gov;
}
}
if (event == CPUFREQ_GOV_POLICY_INIT)
if (!try_module_get(policy->governor->owner))
return -EINVAL;
pr_debug("__cpufreq_governor for CPU %u, event %u\n",
policy->cpu, event);
mutex_lock(&cpufreq_governor_lock);
if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
|| (!policy->governor_enabled
&& (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
mutex_unlock(&cpufreq_governor_lock);
return -EBUSY;
}
if (event == CPUFREQ_GOV_STOP)
policy->governor_enabled = false;
else if (event == CPUFREQ_GOV_START)
policy->governor_enabled = true;
mutex_unlock(&cpufreq_governor_lock);
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--;
} else {
/* Restore original values */
mutex_lock(&cpufreq_governor_lock);
if (event == CPUFREQ_GOV_STOP)
policy->governor_enabled = true;
else if (event == CPUFREQ_GOV_START)
policy->governor_enabled = false;
mutex_unlock(&cpufreq_governor_lock);
}
if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
((event == CPUFREQ_GOV_POLICY_EXIT) && !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)
{
int cpu;
if (!governor)
return;
if (cpufreq_disabled())
return;
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");
}
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(*policy));
cpufreq_cpu_put(cpu_policy);
return 0;
}
EXPORT_SYMBOL(cpufreq_get_policy);
/*
* policy : current policy.
* new_policy: policy to be set.
*/
static int cpufreq_set_policy(struct cpufreq_policy *policy,
struct cpufreq_policy *new_policy)
{
struct cpufreq_governor *old_gov;
int ret;
pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
new_policy->cpu, new_policy->min, new_policy->max);
memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
if (new_policy->min > policy->max || new_policy->max < policy->min)
return -EINVAL;
/* verify the cpu speed can be set within this limit */
ret = cpufreq_driver->verify(new_policy);
if (ret)
return ret;
/* adjust if necessary - all reasons */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_ADJUST, new_policy);
/* adjust if necessary - hardware incompatibility*/
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_INCOMPATIBLE, new_policy);
/*
* verify the cpu speed can be set within this limit, which might be
* different to the first one
*/
ret = cpufreq_driver->verify(new_policy);
if (ret)
return ret;
/* notification of the new policy */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_NOTIFY, new_policy);
policy->min = new_policy->min;
policy->max = new_policy->max;
pr_debug("new min and max freqs are %u - %u kHz\n",
policy->min, policy->max);
if (cpufreq_driver->setpolicy) {
policy->policy = new_policy->policy;
pr_debug("setting range\n");
return cpufreq_driver->setpolicy(new_policy);
}
if (new_policy->governor == policy->governor)
goto out;
pr_debug("governor switch\n");
/* save old, working values */
old_gov = policy->governor;
/* end old governor */
if (old_gov) {
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
up_write(&policy->rwsem);
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
down_write(&policy->rwsem);
}
/* start new governor */
policy->governor = new_policy->governor;
if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
goto out;
up_write(&policy->rwsem);
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
down_write(&policy->rwsem);
}
/* 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;
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
__cpufreq_governor(policy, CPUFREQ_GOV_START);
}
return -EINVAL;
out:
pr_debug("governor: change or update limits\n");
return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}
/**
* 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 *policy = cpufreq_cpu_get(cpu);
struct cpufreq_policy new_policy;
int ret;
if (!policy) {
ret = -ENODEV;
goto no_policy;
}
down_write(&policy->rwsem);
pr_debug("updating policy for CPU %u\n", cpu);
memcpy(&new_policy, policy, sizeof(*policy));
new_policy.min = policy->user_policy.min;
new_policy.max = policy->user_policy.max;
new_policy.policy = policy->user_policy.policy;
new_policy.governor = policy->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 && !cpufreq_driver->setpolicy) {
new_policy.cur = cpufreq_driver->get(cpu);
if (WARN_ON(!new_policy.cur)) {
ret = -EIO;
goto no_policy;
}
if (!policy->cur) {
pr_debug("Driver did not initialize current freq\n");
policy->cur = new_policy.cur;
} else {
if (policy->cur != new_policy.cur && has_target())
cpufreq_out_of_sync(cpu, policy->cur,
new_policy.cur);
}
}
ret = cpufreq_set_policy(policy, &new_policy);
up_write(&policy->rwsem);
cpufreq_cpu_put(policy);
no_policy:
return ret;
}
EXPORT_SYMBOL(cpufreq_update_policy);
static int 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 & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
__cpufreq_add_dev(dev, NULL);
break;
case CPU_DOWN_PREPARE:
__cpufreq_remove_dev_prepare(dev, NULL);
break;
case CPU_POST_DEAD:
__cpufreq_remove_dev_finish(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,
};
/*********************************************************************
* BOOST *
*********************************************************************/
static int cpufreq_boost_set_sw(int state)
{
struct cpufreq_frequency_table *freq_table;
struct cpufreq_policy *policy;
int ret = -EINVAL;
list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
freq_table = cpufreq_frequency_get_table(policy->cpu);
if (freq_table) {
ret = cpufreq_frequency_table_cpuinfo(policy,
freq_table);
if (ret) {
pr_err("%s: Policy frequency update failed\n",
__func__);
break;
}
policy->user_policy.max = policy->max;
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}
}
return ret;
}
int cpufreq_boost_trigger_state(int state)
{
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);
ret = cpufreq_driver->set_boost(state);
if (ret) {
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;
}
int cpufreq_boost_supported(void)
{
if (likely(cpufreq_driver))
return cpufreq_driver->boost_supported;
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
int cpufreq_boost_enabled(void)
{
return cpufreq_driver->boost_enabled;
}
EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
/*********************************************************************
* 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_index ||
driver_data->target) ||
(driver_data->setpolicy && (driver_data->target_index ||
driver_data->target)) ||
(!!driver_data->get_intermediate != !!driver_data->target_intermediate))
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 -EEXIST;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (cpufreq_boost_supported()) {
/*
* Check if driver provides function to enable boost -
* if not, use cpufreq_boost_set_sw as default
*/
if (!cpufreq_driver->set_boost)
cpufreq_driver->set_boost = cpufreq_boost_set_sw;
ret = cpufreq_sysfs_create_file(&boost.attr);
if (ret) {
pr_err("%s: cannot register global BOOST sysfs file\n",
__func__);
goto err_null_driver;
}
}
ret = subsys_interface_register(&cpufreq_interface);
if (ret)
goto err_boost_unreg;
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_boost_unreg:
if (cpufreq_boost_supported())
cpufreq_sysfs_remove_file(&boost.attr);
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);
if (cpufreq_boost_supported())
cpufreq_sysfs_remove_file(&boost.attr);
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
down_write(&cpufreq_rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
up_write(&cpufreq_rwsem);
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
static int __init cpufreq_core_init(void)
{
if (cpufreq_disabled())
return -ENODEV;
cpufreq_global_kobject = kobject_create();
BUG_ON(!cpufreq_global_kobject);
return 0;
}
core_initcall(cpufreq_core_init);