// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/cpufreq/cpufreq.c
 *
 *  Copyright (C) 2001 Russell King
 *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
 *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
 *
 *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
 *      Added handling for CPU hotplug
 *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
 *      Fix handling for CPU hotplug -- affected CPUs
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpu_cooling.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/tick.h>
#include <trace/events/power.h>

static LIST_HEAD(cpufreq_policy_list);

/* Macros to iterate over CPU policies */
#define for_each_suitable_policy(__policy, __active)                     \
        list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
                if ((__active) == !policy_is_inactive(__policy))

#define for_each_active_policy(__policy)                \
        for_each_suitable_policy(__policy, true)
#define for_each_inactive_policy(__policy)              \
        for_each_suitable_policy(__policy, false)

/* Iterate over governors */
static LIST_HEAD(cpufreq_governor_list);
#define for_each_governor(__governor)                           \
        list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)

static char default_governor[CPUFREQ_NAME_LEN];

/*
 * The "cpufreq driver" - the arch- or hardware-dependent low
 * level driver of CPUFreq support, and its spinlock. This lock
 * also protects the cpufreq_cpu_data array.
 */
static struct cpufreq_driver *cpufreq_driver;
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
static DEFINE_RWLOCK(cpufreq_driver_lock);

static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
bool cpufreq_supports_freq_invariance(void)
{
        return static_branch_likely(&cpufreq_freq_invariance);
}

/* Flag to suspend/resume CPUFreq governors */
static bool cpufreq_suspended;

static inline bool has_target(void)
{
        return cpufreq_driver->target_index || cpufreq_driver->target;
}

/* internal prototypes */
static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
static int cpufreq_init_governor(struct cpufreq_policy *policy);
static void cpufreq_exit_governor(struct cpufreq_policy *policy);
static void cpufreq_governor_limits(struct cpufreq_policy *policy);
static int cpufreq_set_policy(struct cpufreq_policy *policy,
                              struct cpufreq_governor *new_gov,
                              unsigned int new_pol);

/*
 * Two notifier lists: the "policy" list is involved in the
 * validation process for a new CPU frequency policy; the
 * "transition" list for kernel code that needs to handle
 * changes to devices when the CPU clock speed changes.
 * The mutex locks both lists.
 */
static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);

static int off __read_mostly;
static int cpufreq_disabled(void)
{
        return off;
}
void disable_cpufreq(void)
{
        off = 1;
}
static DEFINE_MUTEX(cpufreq_governor_mutex);

bool have_governor_per_policy(void)
{
        return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
}
EXPORT_SYMBOL_GPL(have_governor_per_policy);

static struct kobject *cpufreq_global_kobject;

struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
{
        if (have_governor_per_policy())
                return &policy->kobj;
        else
                return cpufreq_global_kobject;
}
EXPORT_SYMBOL_GPL(get_governor_parent_kobj);

static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
        struct kernel_cpustat kcpustat;
        u64 cur_wall_time;
        u64 idle_time;
        u64 busy_time;

        cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());

        kcpustat_cpu_fetch(&kcpustat, cpu);

        busy_time = kcpustat.cpustat[CPUTIME_USER];
        busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
        busy_time += kcpustat.cpustat[CPUTIME_IRQ];
        busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
        busy_time += kcpustat.cpustat[CPUTIME_STEAL];
        busy_time += kcpustat.cpustat[CPUTIME_NICE];

        idle_time = cur_wall_time - busy_time;
        if (wall)
                *wall = div_u64(cur_wall_time, NSEC_PER_USEC);

        return div_u64(idle_time, NSEC_PER_USEC);
}

u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
{
        u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);

        if (idle_time == -1ULL)
                return get_cpu_idle_time_jiffy(cpu, wall);
        else if (!io_busy)
                idle_time += get_cpu_iowait_time_us(cpu, wall);

        return idle_time;
}
EXPORT_SYMBOL_GPL(get_cpu_idle_time);

/*
 * This is a generic cpufreq init() routine which can be used by cpufreq
 * drivers of SMP systems. It will do following:
 * - validate & show freq table passed
 * - set policies transition latency
 * - policy->cpus with all possible CPUs
 */
void cpufreq_generic_init(struct cpufreq_policy *policy,
                struct cpufreq_frequency_table *table,
                unsigned int transition_latency)
{
        policy->freq_table = table;
        policy->cpuinfo.transition_latency = transition_latency;

        /*
         * The driver only supports the SMP configuration where all processors
         * share the clock and voltage and clock.
         */
        cpumask_setall(policy->cpus);
}
EXPORT_SYMBOL_GPL(cpufreq_generic_init);

struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
{
        struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);

        return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);

unsigned int cpufreq_generic_get(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);

        if (!policy || IS_ERR(policy->clk)) {
                pr_err("%s: No %s associated to cpu: %d\n",
                       __func__, policy ? "clk" : "policy", cpu);
                return 0;
        }

        return clk_get_rate(policy->clk) / 1000;
}
EXPORT_SYMBOL_GPL(cpufreq_generic_get);

/**
 * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
 * @cpu: CPU to find the policy for.
 *
 * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
 * the kobject reference counter of that policy.  Return a valid policy on
 * success or NULL on failure.
 *
 * The policy returned by this function has to be released with the help of
 * cpufreq_cpu_put() to balance its kobject reference counter properly.
 */
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
        struct cpufreq_policy *policy = NULL;
        unsigned long flags;

        if (WARN_ON(cpu >= nr_cpu_ids))
                return NULL;

        /* get the cpufreq driver */
        read_lock_irqsave(&cpufreq_driver_lock, flags);

        if (cpufreq_driver) {
                /* get the CPU */
                policy = cpufreq_cpu_get_raw(cpu);
                if (policy)
                        kobject_get(&policy->kobj);
        }

        read_unlock_irqrestore(&cpufreq_driver_lock, flags);

        return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);

/**
 * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
 * @policy: cpufreq policy returned by cpufreq_cpu_get().
 */
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
        kobject_put(&policy->kobj);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);

/**
 * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
 * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
 */
void cpufreq_cpu_release(struct cpufreq_policy *policy)
{
        if (WARN_ON(!policy))
                return;

        lockdep_assert_held(&policy->rwsem);

        up_write(&policy->rwsem);

        cpufreq_cpu_put(policy);
}

/**
 * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
 * @cpu: CPU to find the policy for.
 *
 * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
 * if the policy returned by it is not NULL, acquire its rwsem for writing.
 * Return the policy if it is active or release it and return NULL otherwise.
 *
 * The policy returned by this function has to be released with the help of
 * cpufreq_cpu_release() in order to release its rwsem and balance its usage
 * counter properly.
 */
struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

        if (!policy)
                return NULL;

        down_write(&policy->rwsem);

        if (policy_is_inactive(policy)) {
                cpufreq_cpu_release(policy);
                return NULL;
        }

        return policy;
}

/*********************************************************************
 *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 *********************************************************************/

/**
 * adjust_jiffies - Adjust the system "loops_per_jiffy".
 * @val: CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
 * @ci: Frequency change information.
 *
 * This function alters the system "loops_per_jiffy" for the clock
 * speed change. Note that loops_per_jiffy cannot be updated on SMP
 * systems as each CPU might be scaled differently. So, use the arch
 * per-CPU loops_per_jiffy value wherever possible.
 */
static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
{
#ifndef CONFIG_SMP
        static unsigned long l_p_j_ref;
        static unsigned int l_p_j_ref_freq;

        if (ci->flags & CPUFREQ_CONST_LOOPS)
                return;

        if (!l_p_j_ref_freq) {
                l_p_j_ref = loops_per_jiffy;
                l_p_j_ref_freq = ci->old;
                pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
                         l_p_j_ref, l_p_j_ref_freq);
        }
        if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
                loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
                                                                ci->new);
                pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
                         loops_per_jiffy, ci->new);
        }
#endif
}

/**
 * cpufreq_notify_transition - Notify frequency transition and adjust jiffies.
 * @policy: cpufreq policy to enable fast frequency switching for.
 * @freqs: contain details of the frequency update.
 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
 *
 * This function calls the transition notifiers and adjust_jiffies().
 *
 * It is called twice on all CPU frequency changes that have external effects.
 */
static void cpufreq_notify_transition(struct cpufreq_policy *policy,
                                      struct cpufreq_freqs *freqs,
                                      unsigned int state)
{
        int cpu;

        BUG_ON(irqs_disabled());

        if (cpufreq_disabled())
                return;

        freqs->policy = policy;
        freqs->flags = cpufreq_driver->flags;
        pr_debug("notification %u of frequency transition to %u kHz\n",
                 state, freqs->new);

        switch (state) {
        case CPUFREQ_PRECHANGE:
                /*
                 * Detect if the driver reported a value as "old frequency"
                 * which is not equal to what the cpufreq core thinks is
                 * "old frequency".
                 */
                if (policy->cur && policy->cur != freqs->old) {
                        pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
                                 freqs->old, policy->cur);
                        freqs->old = policy->cur;
                }

                srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
                                         CPUFREQ_PRECHANGE, freqs);

                adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
                break;

        case CPUFREQ_POSTCHANGE:
                adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
                pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
                         cpumask_pr_args(policy->cpus));

                for_each_cpu(cpu, policy->cpus)
                        trace_cpu_frequency(freqs->new, cpu);

                srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
                                         CPUFREQ_POSTCHANGE, freqs);

                cpufreq_stats_record_transition(policy, freqs->new);
                policy->cur = freqs->new;
        }
}

/* Do post notifications when there are chances that transition has failed */
static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
                struct cpufreq_freqs *freqs, int transition_failed)
{
        cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
        if (!transition_failed)
                return;

        swap(freqs->old, freqs->new);
        cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
        cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
}

void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
                struct cpufreq_freqs *freqs)
{

        /*
         * Catch double invocations of _begin() which lead to self-deadlock.
         * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
         * doesn't invoke _begin() on their behalf, and hence the chances of
         * double invocations are very low. Moreover, there are scenarios
         * where these checks can emit false-positive warnings in these
         * drivers; so we avoid that by skipping them altogether.
         */
        WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
                                && current == policy->transition_task);

wait:
        wait_event(policy->transition_wait, !policy->transition_ongoing);

        spin_lock(&policy->transition_lock);

        if (unlikely(policy->transition_ongoing)) {
                spin_unlock(&policy->transition_lock);
                goto wait;
        }

        policy->transition_ongoing = true;
        policy->transition_task = current;

        spin_unlock(&policy->transition_lock);

        cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
}
EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);

void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
                struct cpufreq_freqs *freqs, int transition_failed)
{
        if (WARN_ON(!policy->transition_ongoing))
                return;

        cpufreq_notify_post_transition(policy, freqs, transition_failed);

        arch_set_freq_scale(policy->related_cpus,
                            policy->cur,
                            policy->cpuinfo.max_freq);

        policy->transition_ongoing = false;
        policy->transition_task = NULL;

        wake_up(&policy->transition_wait);
}
EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);

/*
 * Fast frequency switching status count.  Positive means "enabled", negative
 * means "disabled" and 0 means "not decided yet".
 */
static int cpufreq_fast_switch_count;
static DEFINE_MUTEX(cpufreq_fast_switch_lock);

static void cpufreq_list_transition_notifiers(void)
{
        struct notifier_block *nb;

        pr_info("Registered transition notifiers:\n");

        mutex_lock(&cpufreq_transition_notifier_list.mutex);

        for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
                pr_info("%pS\n", nb->notifier_call);

        mutex_unlock(&cpufreq_transition_notifier_list.mutex);
}

/**
 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
 * @policy: cpufreq policy to enable fast frequency switching for.
 *
 * Try to enable fast frequency switching for @policy.
 *
 * The attempt will fail if there is at least one transition notifier registered
 * at this point, as fast frequency switching is quite fundamentally at odds
 * with transition notifiers.  Thus if successful, it will make registration of
 * transition notifiers fail going forward.
 */
void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
{
        lockdep_assert_held(&policy->rwsem);

        if (!policy->fast_switch_possible)
                return;

        mutex_lock(&cpufreq_fast_switch_lock);
        if (cpufreq_fast_switch_count >= 0) {
                cpufreq_fast_switch_count++;
                policy->fast_switch_enabled = true;
        } else {
                pr_warn("CPU%u: Fast frequency switching not enabled\n",
                        policy->cpu);
                cpufreq_list_transition_notifiers();
        }
        mutex_unlock(&cpufreq_fast_switch_lock);
}
EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);

/**
 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
 * @policy: cpufreq policy to disable fast frequency switching for.
 */
void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
{
        mutex_lock(&cpufreq_fast_switch_lock);
        if (policy->fast_switch_enabled) {
                policy->fast_switch_enabled = false;
                if (!WARN_ON(cpufreq_fast_switch_count <= 0))
                        cpufreq_fast_switch_count--;
        }
        mutex_unlock(&cpufreq_fast_switch_lock);
}
EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);

static unsigned int __resolve_freq(struct cpufreq_policy *policy,
                unsigned int target_freq, unsigned int relation)
{
        unsigned int idx;

        target_freq = clamp_val(target_freq, policy->min, policy->max);

        if (!cpufreq_driver->target_index)
                return target_freq;

        idx = cpufreq_frequency_table_target(policy, target_freq, relation);
        policy->cached_resolved_idx = idx;
        policy->cached_target_freq = target_freq;
        return policy->freq_table[idx].frequency;
}

/**
 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
 * one.
 * @policy: associated policy to interrogate
 * @target_freq: target frequency to resolve.
 *
 * The target to driver frequency mapping is cached in the policy.
 *
 * Return: Lowest driver-supported frequency greater than or equal to the
 * given target_freq, subject to policy (min/max) and driver limitations.
 */
unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
                                         unsigned int target_freq)
{
        return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_L);
}
EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);

unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
{
        unsigned int latency;

        if (policy->transition_delay_us)
                return policy->transition_delay_us;

        latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
        if (latency) {
                /*
                 * For platforms that can change the frequency very fast (< 10
                 * us), the above formula gives a decent transition delay. But
                 * for platforms where transition_latency is in milliseconds, it
                 * ends up giving unrealistic values.
                 *
                 * Cap the default transition delay to 10 ms, which seems to be
                 * a reasonable amount of time after which we should reevaluate
                 * the frequency.
                 */
                return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
        }

        return LATENCY_MULTIPLIER;
}
EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);

/*********************************************************************
 *                          SYSFS INTERFACE                          *
 *********************************************************************/
static ssize_t show_boost(struct kobject *kobj,
                          struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
}

static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
                           const char *buf, size_t count)
{
        int ret, enable;

        ret = sscanf(buf, "%d", &enable);
        if (ret != 1 || enable < 0 || enable > 1)
                return -EINVAL;

        if (cpufreq_boost_trigger_state(enable)) {
                pr_err("%s: Cannot %s BOOST!\n",
                       __func__, enable ? "enable" : "disable");
                return -EINVAL;
        }

        pr_debug("%s: cpufreq BOOST %s\n",
                 __func__, enable ? "enabled" : "disabled");

        return count;
}
define_one_global_rw(boost);

static struct cpufreq_governor *find_governor(const char *str_governor)
{
        struct cpufreq_governor *t;

        for_each_governor(t)
                if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
                        return t;

        return NULL;
}

static struct cpufreq_governor *get_governor(const char *str_governor)
{
        struct cpufreq_governor *t;

        mutex_lock(&cpufreq_governor_mutex);
        t = find_governor(str_governor);
        if (!t)
                goto unlock;

        if (!try_module_get(t->owner))
                t = NULL;

unlock:
        mutex_unlock(&cpufreq_governor_mutex);

        return t;
}

static unsigned int cpufreq_parse_policy(char *str_governor)
{
        if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
                return CPUFREQ_POLICY_PERFORMANCE;

        if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
                return CPUFREQ_POLICY_POWERSAVE;

        return CPUFREQ_POLICY_UNKNOWN;
}

/**
 * cpufreq_parse_governor - parse a governor string only for has_target()
 * @str_governor: Governor name.
 */
static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
{
        struct cpufreq_governor *t;

        t = get_governor(str_governor);
        if (t)
                return t;

        if (request_module("cpufreq_%s", str_governor))
                return NULL;

        return get_governor(str_governor);
}

/*
 * cpufreq_per_cpu_attr_read() / show_##file_name() -
 * print out cpufreq information
 *
 * Write out information from cpufreq_driver->policy[cpu]; object must be
 * "unsigned int".
 */

#define show_one(file_name, object)                     \
static ssize_t show_##file_name                         \
(struct cpufreq_policy *policy, char *buf)              \
{                                                       \
        return sprintf(buf, "%u\n", policy->object);    \
}

show_one(cpuinfo_min_freq, cpuinfo.min_freq);
show_one(cpuinfo_max_freq, cpuinfo.max_freq);
show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
show_one(scaling_min_freq, min);
show_one(scaling_max_freq, max);

__weak unsigned int arch_freq_get_on_cpu(int cpu)
{
        return 0;
}

static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
{
        ssize_t ret;
        unsigned int freq;

        freq = arch_freq_get_on_cpu(policy->cpu);
        if (freq)
                ret = sprintf(buf, "%u\n", freq);
        else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
                ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
        else
                ret = sprintf(buf, "%u\n", policy->cur);
        return ret;
}

/*
 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 */
#define store_one(file_name, object)                    \
static ssize_t store_##file_name                                        \
(struct cpufreq_policy *policy, const char *buf, size_t count)          \
{                                                                       \
        unsigned long val;                                              \
        int ret;                                                        \
                                                                        \
        ret = sscanf(buf, "%lu", &val);                                 \
        if (ret != 1)                                                   \
                return -EINVAL;                                         \
                                                                        \
        ret = freq_qos_update_request(policy->object##_freq_req, val);\
        return ret >= 0 ? count : ret;                                  \
}

store_one(scaling_min_freq, min);
store_one(scaling_max_freq, max);

/*
 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 */
static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
                                        char *buf)
{
        unsigned int cur_freq = __cpufreq_get(policy);

        if (cur_freq)
                return sprintf(buf, "%u\n", cur_freq);

        return sprintf(buf, "<unknown>\n");
}

/*
 * show_scaling_governor - show the current policy for the specified CPU
 */
static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
{
        if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
                return sprintf(buf, "powersave\n");
        else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
                return sprintf(buf, "performance\n");
        else if (policy->governor)
                return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
                                policy->governor->name);
        return -EINVAL;
}

/*
 * store_scaling_governor - store policy for the specified CPU
 */
static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
                                        const char *buf, size_t count)
{
        char str_governor[16];
        int ret;

        ret = sscanf(buf, "%15s", str_governor);
        if (ret != 1)
                return -EINVAL;

        if (cpufreq_driver->setpolicy) {
                unsigned int new_pol;

                new_pol = cpufreq_parse_policy(str_governor);
                if (!new_pol)
                        return -EINVAL;

                ret = cpufreq_set_policy(policy, NULL, new_pol);
        } else {
                struct cpufreq_governor *new_gov;

                new_gov = cpufreq_parse_governor(str_governor);
                if (!new_gov)
                        return -EINVAL;

                ret = cpufreq_set_policy(policy, new_gov,
                                         CPUFREQ_POLICY_UNKNOWN);

                module_put(new_gov->owner);
        }

        return ret ? ret : count;
}

/*
 * show_scaling_driver - show the cpufreq driver currently loaded
 */
static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
{
        return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
}

/*
 * show_scaling_available_governors - show the available CPUfreq governors
 */
static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
                                                char *buf)
{
        ssize_t i = 0;
        struct cpufreq_governor *t;

        if (!has_target()) {
                i += sprintf(buf, "performance powersave");
                goto out;
        }

        mutex_lock(&cpufreq_governor_mutex);
        for_each_governor(t) {
                if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
                    - (CPUFREQ_NAME_LEN + 2)))
                        break;
                i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
        }
        mutex_unlock(&cpufreq_governor_mutex);
out:
        i += sprintf(&buf[i], "\n");
        return i;
}

ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
{
        ssize_t i = 0;
        unsigned int cpu;

        for_each_cpu(cpu, mask) {
                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;
        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 (!fattr->show)
                return -EIO;

        down_read(&policy->rwsem);
        ret = fattr->show(policy, buf);
        up_read(&policy->rwsem);

        return ret;
}

static ssize_t store(struct kobject *kobj, struct attribute *attr,
                     const char *buf, size_t count)
{
        struct cpufreq_policy *policy = to_policy(kobj);
        struct freq_attr *fattr = to_attr(attr);
        ssize_t ret = -EINVAL;

        if (!fattr->store)
                return -EIO;

        /*
         * cpus_read_trylock() is used here to work around a circular lock
         * dependency problem with respect to the cpufreq_register_driver().
         */
        if (!cpus_read_trylock())
                return -EBUSY;

        if (cpu_online(policy->cpu)) {
                down_write(&policy->rwsem);
                ret = fattr->store(policy, buf, count);
                up_write(&policy->rwsem);
        }

        cpus_read_unlock();

        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,
};

static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
{
        struct device *dev = get_cpu_device(cpu);

        if (unlikely(!dev))
                return;

        if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
                return;

        dev_dbg(dev, "%s: Adding symlink\n", __func__);
        if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
                dev_err(dev, "cpufreq symlink creation failed\n");
}

static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
                                   struct device *dev)
{
        dev_dbg(dev, "%s: Removing symlink\n", __func__);
        sysfs_remove_link(&dev->kobj, "cpufreq");
}

static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
{
        struct freq_attr **drv_attr;
        int ret = 0;

        /* set up files for this cpu device */
        drv_attr = cpufreq_driver->attr;
        while (drv_attr && *drv_attr) {
                ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
                if (ret)
                        return ret;
                drv_attr++;
        }
        if (cpufreq_driver->get) {
                ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
                if (ret)
                        return ret;
        }

        ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
        if (ret)
                return ret;

        if (cpufreq_driver->bios_limit) {
                ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
                if (ret)
                        return ret;
        }

        return 0;
}

static int cpufreq_init_policy(struct cpufreq_policy *policy)
{
        struct cpufreq_governor *gov = NULL;
        unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
        int ret;

        if (has_target()) {
                /* Update policy governor to the one used before hotplug. */
                gov = get_governor(policy->last_governor);
                if (gov) {
                        pr_debug("Restoring governor %s for cpu %d\n",
                                 gov->name, policy->cpu);
                } else {
                        gov = get_governor(default_governor);
                }

                if (!gov) {
                        gov = cpufreq_default_governor();
                        __module_get(gov->owner);
                }

        } else {

                /* Use the default policy if there is no last_policy. */
                if (policy->last_policy) {
                        pol = policy->last_policy;
                } else {
                        pol = cpufreq_parse_policy(default_governor);
                        /*
                         * In case the default governor is neither "performance"
                         * nor "powersave", fall back to the initial policy
                         * value set by the driver.
                         */
                        if (pol == CPUFREQ_POLICY_UNKNOWN)
                                pol = policy->policy;
                }
                if (pol != CPUFREQ_POLICY_PERFORMANCE &&
                    pol != CPUFREQ_POLICY_POWERSAVE)
                        return -ENODATA;
        }

        ret = cpufreq_set_policy(policy, gov, pol);
        if (gov)
                module_put(gov->owner);

        return ret;
}

static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
        int ret = 0;

        /* Has this CPU been taken care of already? */
        if (cpumask_test_cpu(cpu, policy->cpus))
                return 0;

        down_write(&policy->rwsem);
        if (has_target())
                cpufreq_stop_governor(policy);

        cpumask_set_cpu(cpu, policy->cpus);

        if (has_target()) {
                ret = cpufreq_start_governor(policy);
                if (ret)
                        pr_err("%s: Failed to start governor\n", __func__);
        }
        up_write(&policy->rwsem);
        return ret;
}

void refresh_frequency_limits(struct cpufreq_policy *policy)
{
        if (!policy_is_inactive(policy)) {
                pr_debug("updating policy for CPU %u\n", policy->cpu);

                cpufreq_set_policy(policy, policy->governor, policy->policy);
        }
}
EXPORT_SYMBOL(refresh_frequency_limits);

static void handle_update(struct work_struct *work)
{
        struct cpufreq_policy *policy =
                container_of(work, struct cpufreq_policy, update);

        pr_debug("handle_update for cpu %u called\n", policy->cpu);
        down_write(&policy->rwsem);
        refresh_frequency_limits(policy);
        up_write(&policy->rwsem);
}

static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
                                void *data)
{
        struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);

        schedule_work(&policy->update);
        return 0;
}

static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
                                void *data)
{
        struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);

        schedule_work(&policy->update);
        return 0;
}

static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
{
        struct kobject *kobj;
        struct completion *cmp;

        down_write(&policy->rwsem);
        cpufreq_stats_free_table(policy);
        kobj = &policy->kobj;
        cmp = &policy->kobj_unregister;
        up_write(&policy->rwsem);
        kobject_put(kobj);

        /*
         * We need to make sure that the underlying kobj is
         * actually not referenced anymore by anybody before we
         * proceed with unloading.
         */
        pr_debug("waiting for dropping of refcount\n");
        wait_for_completion(cmp);
        pr_debug("wait complete\n");
}

static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
{
        struct cpufreq_policy *policy;
        struct device *dev = get_cpu_device(cpu);
        int ret;

        if (!dev)
                return NULL;

        policy = kzalloc(sizeof(*policy), GFP_KERNEL);
        if (!policy)
                return NULL;

        if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
                goto err_free_policy;

        if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
                goto err_free_cpumask;

        if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
                goto err_free_rcpumask;

        ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
                                   cpufreq_global_kobject, "policy%u", cpu);
        if (ret) {
                dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
                /*
                 * The entire policy object will be freed below, but the extra
                 * memory allocated for the kobject name needs to be freed by
                 * releasing the kobject.
                 */
                kobject_put(&policy->kobj);
                goto err_free_real_cpus;
        }

        freq_constraints_init(&policy->constraints);

        policy->nb_min.notifier_call = cpufreq_notifier_min;
        policy->nb_max.notifier_call = cpufreq_notifier_max;

        ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
                                    &policy->nb_min);
        if (ret) {
                dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
                        ret, cpumask_pr_args(policy->cpus));
                goto err_kobj_remove;
        }

        ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
                                    &policy->nb_max);
        if (ret) {
                dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
                        ret, cpumask_pr_args(policy->cpus));
                goto err_min_qos_notifier;
        }

        INIT_LIST_HEAD(&policy->policy_list);
        init_rwsem(&policy->rwsem);
        spin_lock_init(&policy->transition_lock);
        init_waitqueue_head(&policy->transition_wait);
        init_completion(&policy->kobj_unregister);
        INIT_WORK(&policy->update, handle_update);

        policy->cpu = cpu;
        return policy;

err_min_qos_notifier:
        freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
                                 &policy->nb_min);
err_kobj_remove:
        cpufreq_policy_put_kobj(policy);
err_free_real_cpus:
        free_cpumask_var(policy->real_cpus);
err_free_rcpumask:
        free_cpumask_var(policy->related_cpus);
err_free_cpumask:
        free_cpumask_var(policy->cpus);
err_free_policy:
        kfree(policy);

        return NULL;
}

static void cpufreq_policy_free(struct cpufreq_policy *policy)
{
        unsigned long flags;
        int cpu;

        /* Remove policy from list */
        write_lock_irqsave(&cpufreq_driver_lock, flags);
        list_del(&policy->policy_list);

        for_each_cpu(cpu, policy->related_cpus)
                per_cpu(cpufreq_cpu_data, cpu) = NULL;
        write_unlock_irqrestore(&cpufreq_driver_lock, flags);

        freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
                                 &policy->nb_max);
        freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
                                 &policy->nb_min);

        /* Cancel any pending policy->update work before freeing the policy. */
        cancel_work_sync(&policy->update);

        if (policy->max_freq_req) {
                /*
                 * CPUFREQ_CREATE_POLICY notification is sent only after
                 * successfully adding max_freq_req request.
                 */
                blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
                                             CPUFREQ_REMOVE_POLICY, policy);
                freq_qos_remove_request(policy->max_freq_req);
        }

        freq_qos_remove_request(policy->min_freq_req);
        kfree(policy->min_freq_req);

        cpufreq_policy_put_kobj(policy);
        free_cpumask_var(policy->real_cpus);
        free_cpumask_var(policy->related_cpus);
        free_cpumask_var(policy->cpus);
        kfree(policy);
}

static int cpufreq_online(unsigned int cpu)
{
        struct cpufreq_policy *policy;
        bool new_policy;
        unsigned long flags;
        unsigned int j;
        int ret;

        pr_debug("%s: bringing CPU%u online\n", __func__, cpu);

        /* Check if this CPU already has a policy to manage it */
        policy = per_cpu(cpufreq_cpu_data, cpu);
        if (policy) {
                WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
                if (!policy_is_inactive(policy))
                        return cpufreq_add_policy_cpu(policy, cpu);

                /* This is the only online CPU for the policy.  Start over. */
                new_policy = false;
                down_write(&policy->rwsem);
                policy->cpu = cpu;
                policy->governor = NULL;
                up_write(&policy->rwsem);
        } else {
                new_policy = true;
                policy = cpufreq_policy_alloc(cpu);
                if (!policy)
                        return -ENOMEM;
        }

        if (!new_policy && cpufreq_driver->online) {
                ret = cpufreq_driver->online(policy);
                if (ret) {
                        pr_debug("%s: %d: initialization failed\n", __func__,
                                 __LINE__);
                        goto out_exit_policy;
                }

                /* Recover policy->cpus using related_cpus */
                cpumask_copy(policy->cpus, policy->related_cpus);
        } else {
                cpumask_copy(policy->cpus, cpumask_of(cpu));

                /*
                 * Call driver. From then on the cpufreq must be able
                 * to accept all calls to ->verify and ->setpolicy for this CPU.
                 */
                ret = cpufreq_driver->init(policy);
                if (ret) {
                        pr_debug("%s: %d: initialization failed\n", __func__,
                                 __LINE__);
                        goto out_free_policy;
                }

                /*
                 * The initialization has succeeded and the policy is online.
                 * If there is a problem with its frequency table, take it
                 * offline and drop it.
                 */
                ret = cpufreq_table_validate_and_sort(policy);
                if (ret)
                        goto out_offline_policy;

                /* related_cpus should at least include policy->cpus. */
                cpumask_copy(policy->related_cpus, policy->cpus);
        }

        down_write(&policy->rwsem);
        /*
         * affected cpus must always be the one, which are online. We aren't
         * managing offline cpus here.
         */
        cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);

        if (new_policy) {
                for_each_cpu(j, policy->related_cpus) {
                        per_cpu(cpufreq_cpu_data, j) = policy;
                        add_cpu_dev_symlink(policy, j);
                }

                policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
                                               GFP_KERNEL);
                if (!policy->min_freq_req) {
                        ret = -ENOMEM;
                        goto out_destroy_policy;
                }

                ret = freq_qos_add_request(&policy->constraints,
                                           policy->min_freq_req, FREQ_QOS_MIN,
                                           policy->min);
                if (ret < 0) {
                        /*
                         * So we don't call freq_qos_remove_request() for an
                         * uninitialized request.
                         */
                        kfree(policy->min_freq_req);
                        policy->min_freq_req = NULL;
                        goto out_destroy_policy;
                }

                /*
                 * This must be initialized right here to avoid calling
                 * freq_qos_remove_request() on uninitialized request in case
                 * of errors.
                 */
                policy->max_freq_req = policy->min_freq_req + 1;

                ret = freq_qos_add_request(&policy->constraints,
                                           policy->max_freq_req, FREQ_QOS_MAX,
                                           policy->max);
                if (ret < 0) {
                        policy->max_freq_req = NULL;
                        goto out_destroy_policy;
                }

                blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
                                CPUFREQ_CREATE_POLICY, policy);
        }

        if (cpufreq_driver->get && has_target()) {
                policy->cur = cpufreq_driver->get(policy->cpu);
                if (!policy->cur) {
                        ret = -EIO;
                        pr_err("%s: ->get() failed\n", __func__);
                        goto out_destroy_policy;
                }
        }

        /*
         * Sometimes boot loaders set CPU frequency to a value outside of
         * frequency table present with cpufreq core. In such cases CPU might be
         * unstable if it has to run on that frequency for long duration of time
         * and so its better to set it to a frequency which is specified in
         * freq-table. This also makes cpufreq stats inconsistent as
         * cpufreq-stats would fail to register because current frequency of CPU
         * isn't found in freq-table.
         *
         * Because we don't want this change to effect boot process badly, we go
         * for the next freq which is >= policy->cur ('cur' must be set by now,
         * otherwise we will end up setting freq to lowest of the table as 'cur'
         * is initialized to zero).
         *
         * We are passing target-freq as "policy->cur - 1" otherwise
         * __cpufreq_driver_target() would simply fail, as policy->cur will be
         * equal to target-freq.
         */
        if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
            && has_target()) {
                unsigned int old_freq = policy->cur;

                /* Are we running at unknown frequency ? */
                ret = cpufreq_frequency_table_get_index(policy, old_freq);
                if (ret == -EINVAL) {
                        ret = __cpufreq_driver_target(policy, old_freq - 1,
                                                      CPUFREQ_RELATION_L);

                        /*
                         * Reaching here after boot in a few seconds may not
                         * mean that system will remain stable at "unknown"
                         * frequency for longer duration. Hence, a BUG_ON().
                         */
                        BUG_ON(ret);
                        pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
                                __func__, policy->cpu, old_freq, policy->cur);
                }
        }

        if (new_policy) {
                ret = cpufreq_add_dev_interface(policy);
                if (ret)
                        goto out_destroy_policy;

                cpufreq_stats_create_table(policy);

                write_lock_irqsave(&cpufreq_driver_lock, flags);
                list_add(&policy->policy_list, &cpufreq_policy_list);
                write_unlock_irqrestore(&cpufreq_driver_lock, flags);
        }

        ret = cpufreq_init_policy(policy);
        if (ret) {
                pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
                       __func__, cpu, ret);
                goto out_destroy_policy;
        }

        up_write(&policy->rwsem);

        kobject_uevent(&policy->kobj, KOBJ_ADD);

        /* Callback for handling stuff after policy is ready */
        if (cpufreq_driver->ready)
                cpufreq_driver->ready(policy);

        if (cpufreq_thermal_control_enabled(cpufreq_driver))
                policy->cdev = of_cpufreq_cooling_register(policy);

        pr_debug("initialization complete\n");

        return 0;

out_destroy_policy:
        for_each_cpu(j, policy->real_cpus)
                remove_cpu_dev_symlink(policy, get_cpu_device(j));

        up_write(&policy->rwsem);

out_offline_policy:
        if (cpufreq_driver->offline)
                cpufreq_driver->offline(policy);

out_exit_policy:
        if (cpufreq_driver->exit)
                cpufreq_driver->exit(policy);

out_free_policy:
        cpufreq_policy_free(policy);
        return ret;
}

/**
 * cpufreq_add_dev - the cpufreq interface for a CPU device.
 * @dev: CPU device.
 * @sif: Subsystem interface structure pointer (not used)
 */
static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
{
        struct cpufreq_policy *policy;
        unsigned cpu = dev->id;
        int ret;

        dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);

        if (cpu_online(cpu)) {
                ret = cpufreq_online(cpu);
                if (ret)
                        return ret;
        }

        /* Create sysfs link on CPU registration */
        policy = per_cpu(cpufreq_cpu_data, cpu);
        if (policy)
                add_cpu_dev_symlink(policy, cpu);

        return 0;
}

static int cpufreq_offline(unsigned int cpu)
{
        struct cpufreq_policy *policy;
        int ret;

        pr_debug("%s: unregistering CPU %u\n", __func__, cpu);

        policy = cpufreq_cpu_get_raw(cpu);
        if (!policy) {
                pr_debug("%s: No cpu_data found\n", __func__);
                return 0;
        }

        down_write(&policy->rwsem);
        if (has_target())
                cpufreq_stop_governor(policy);

        cpumask_clear_cpu(cpu, policy->cpus);

        if (policy_is_inactive(policy)) {
                if (has_target())
                        strncpy(policy->last_governor, policy->governor->name,
                                CPUFREQ_NAME_LEN);
                else
                        policy->last_policy = policy->policy;
        } else if (cpu == policy->cpu) {
                /* Nominate new CPU */
                policy->cpu = cpumask_any(policy->cpus);
        }

        /* Start governor again for active policy */
        if (!policy_is_inactive(policy)) {
                if (has_target()) {
                        ret = cpufreq_start_governor(policy);
                        if (ret)
                                pr_err("%s: Failed to start governor\n", __func__);
                }

                goto unlock;
        }

        if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
                cpufreq_cooling_unregister(policy->cdev);
                policy->cdev = NULL;
        }

        if (has_target())
                cpufreq_exit_governor(policy);

        /*
         * Perform the ->offline() during light-weight tear-down, as
         * that allows fast recovery when the CPU comes back.
         */
        if (cpufreq_driver->offline) {
                cpufreq_driver->offline(policy);
        } else if (cpufreq_driver->exit) {
                cpufreq_driver->exit(policy);
                policy->freq_table = NULL;
        }

unlock:
        up_write(&policy->rwsem);
        return 0;
}

/*
 * cpufreq_remove_dev - remove a CPU device
 *
 * Removes the cpufreq interface for a CPU device.
 */
static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
        unsigned int cpu = dev->id;
        struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);

        if (!policy)
                return;

        if (cpu_online(cpu))
                cpufreq_offline(cpu);

        cpumask_clear_cpu(cpu, policy->real_cpus);
        remove_cpu_dev_symlink(policy, dev);

        if (cpumask_empty(policy->real_cpus)) {
                /* We did light-weight exit earlier, do full tear down now */
                if (cpufreq_driver->offline)
                        cpufreq_driver->exit(policy);

                cpufreq_policy_free(policy);
        }
}

/**
 * cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
 * @policy: Policy managing CPUs.
 * @new_freq: New CPU frequency.
 *
 * Adjust to the current frequency first and clean up later by either calling
 * cpufreq_update_policy(), or scheduling handle_update().
 */
static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
                                unsigned int new_freq)
{
        struct cpufreq_freqs freqs;

        pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
                 policy->cur, new_freq);

        freqs.old = policy->cur;
        freqs.new = new_freq;

        cpufreq_freq_transition_begin(policy, &freqs);
        cpufreq_freq_transition_end(policy, &freqs, 0);
}

static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
{
        unsigned int new_freq;

        new_freq = cpufreq_driver->get(policy->cpu);
        if (!new_freq)
                return 0;

        /*
         * If fast frequency switching is used with the given policy, the check
         * against policy->cur is pointless, so skip it in that case.
         */
        if (policy->fast_switch_enabled || !has_target())
                return new_freq;

        if (policy->cur != new_freq) {
                cpufreq_out_of_sync(policy, new_freq);
                if (update)
                        schedule_work(&policy->update);
        }

        return new_freq;
}

/**
 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
 * @cpu: CPU number
 *
 * This is the last known freq, without actually getting it from the driver.
 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
 */
unsigned int cpufreq_quick_get(unsigned int cpu)
{
        struct cpufreq_policy *policy;
        unsigned int ret_freq = 0;
        unsigned long flags;

        read_lock_irqsave(&cpufreq_driver_lock, flags);

        if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
                ret_freq = cpufreq_driver->get(cpu);
                read_unlock_irqrestore(&cpufreq_driver_lock, flags);
                return ret_freq;
        }

        read_unlock_irqrestore(&cpufreq_driver_lock, flags);

        policy = cpufreq_cpu_get(cpu);
        if (policy) {
                ret_freq = policy->cur;
                cpufreq_cpu_put(policy);
        }

        return ret_freq;
}
EXPORT_SYMBOL(cpufreq_quick_get);

/**
 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
 * @cpu: CPU number
 *
 * Just return the max possible frequency for a given CPU.
 */
unsigned int cpufreq_quick_get_max(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
        unsigned int ret_freq = 0;

        if (policy) {
                ret_freq = policy->max;
                cpufreq_cpu_put(policy);
        }

        return ret_freq;
}
EXPORT_SYMBOL(cpufreq_quick_get_max);

/**
 * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
 * @cpu: CPU number
 *
 * The default return value is the max_freq field of cpuinfo.
 */
__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
        unsigned int ret_freq = 0;

        if (policy) {
                ret_freq = policy->cpuinfo.max_freq;
                cpufreq_cpu_put(policy);
        }

        return ret_freq;
}
EXPORT_SYMBOL(cpufreq_get_hw_max_freq);

static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
{
        if (unlikely(policy_is_inactive(policy)))
                return 0;

        return cpufreq_verify_current_freq(policy, true);
}

/**
 * cpufreq_get - get the current CPU frequency (in kHz)
 * @cpu: CPU number
 *
 * Get the CPU current (static) CPU frequency
 */
unsigned int cpufreq_get(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
        unsigned int ret_freq = 0;

        if (policy) {
                down_read(&policy->rwsem);
                if (cpufreq_driver->get)
                        ret_freq = __cpufreq_get(policy);
                up_read(&policy->rwsem);

                cpufreq_cpu_put(policy);
        }

        return ret_freq;
}
EXPORT_SYMBOL(cpufreq_get);

static struct subsys_interface cpufreq_interface = {
        .name           = "cpufreq",
        .subsys         = &cpu_subsys,
        .add_dev        = cpufreq_add_dev,
        .remove_dev     = cpufreq_remove_dev,
};

/*
 * In case platform wants some specific frequency to be configured
 * during suspend..
 */
int cpufreq_generic_suspend(struct cpufreq_policy *policy)
{
        int ret;

        if (!policy->suspend_freq) {
                pr_debug("%s: suspend_freq not defined\n", __func__);
                return 0;
        }

        pr_debug("%s: Setting suspend-freq: %u\n", __func__,
                        policy->suspend_freq);

        ret = __cpufreq_driver_target(policy, policy->suspend_freq,
                        CPUFREQ_RELATION_H);
        if (ret)
                pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
                                __func__, policy->suspend_freq, ret);

        return ret;
}
EXPORT_SYMBOL(cpufreq_generic_suspend);

/**
 * cpufreq_suspend() - Suspend CPUFreq governors.
 *
 * Called during system wide Suspend/Hibernate cycles for suspending governors
 * as some platforms can't change frequency after this point in suspend cycle.
 * Because some of the devices (like: i2c, regulators, etc) they use for
 * changing frequency are suspended quickly after this point.
 */
void cpufreq_suspend(void)
{
        struct cpufreq_policy *policy;

        if (!cpufreq_driver)
                return;

        if (!has_target() && !cpufreq_driver->suspend)
                goto suspend;

        pr_debug("%s: Suspending Governors\n", __func__);

        for_each_active_policy(policy) {
                if (has_target()) {
                        down_write(&policy->rwsem);
                        cpufreq_stop_governor(policy);
                        up_write(&policy->rwsem);
                }

                if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
                        pr_err("%s: Failed to suspend driver: %s\n", __func__,
                                cpufreq_driver->name);
        }

suspend:
        cpufreq_suspended = true;
}

/**
 * cpufreq_resume() - Resume CPUFreq governors.
 *
 * Called during system wide Suspend/Hibernate cycle for resuming governors that
 * are suspended with cpufreq_suspend().
 */
void cpufreq_resume(void)
{
        struct cpufreq_policy *policy;
        int ret;

        if (!cpufreq_driver)
                return;

        if (unlikely(!cpufreq_suspended))
                return;

        cpufreq_suspended = false;

        if (!has_target() && !cpufreq_driver->resume)
                return;

        pr_debug("%s: Resuming Governors\n", __func__);

        for_each_active_policy(policy) {
                if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
                        pr_err("%s: Failed to resume driver: %p\n", __func__,
                                policy);
                } else if (has_target()) {
                        down_write(&policy->rwsem);
                        ret = cpufreq_start_governor(policy);
                        up_write(&policy->rwsem);

                        if (ret)
                                pr_err("%s: Failed to start governor for policy: %p\n",
                                       __func__, policy);
                }
        }
}

/**
 * cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
 * @flags: Flags to test against the current cpufreq driver's flags.
 *
 * Assumes that the driver is there, so callers must ensure that this is the
 * case.
 */
bool cpufreq_driver_test_flags(u16 flags)
{
        return !!(cpufreq_driver->flags & flags);
}

/**
 * cpufreq_get_current_driver - Return the current driver's name.
 *
 * Return the name string of the currently registered cpufreq driver or NULL if
 * none.
 */
const char *cpufreq_get_current_driver(void)
{
        if (cpufreq_driver)
                return cpufreq_driver->name;

        return NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);

/**
 * cpufreq_get_driver_data - Return current driver data.
 *
 * Return the private data of the currently registered cpufreq driver, or NULL
 * if no cpufreq driver has been registered.
 */
void *cpufreq_get_driver_data(void)
{
        if (cpufreq_driver)
                return cpufreq_driver->driver_data;

        return NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);

/*********************************************************************
 *                     NOTIFIER LISTS INTERFACE                      *
 *********************************************************************/

/**
 * cpufreq_register_notifier - Register a notifier with cpufreq.
 * @nb: notifier function to register.
 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
 *
 * Add a notifier to one of two lists: either a list of notifiers that run on
 * clock rate changes (once before and once after every transition), or a list
 * of notifiers that ron on cpufreq policy changes.
 *
 * This function may sleep and it has the same return values as
 * blocking_notifier_chain_register().
 */
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
{
        int ret;

        if (cpufreq_disabled())
                return -EINVAL;

        switch (list) {
        case CPUFREQ_TRANSITION_NOTIFIER:
                mutex_lock(&cpufreq_fast_switch_lock);

                if (cpufreq_fast_switch_count > 0) {
                        mutex_unlock(&cpufreq_fast_switch_lock);
                        return -EBUSY;
                }
                ret = srcu_notifier_chain_register(
                                &cpufreq_transition_notifier_list, nb);
                if (!ret)
                        cpufreq_fast_switch_count--;

                mutex_unlock(&cpufreq_fast_switch_lock);
                break;
        case CPUFREQ_POLICY_NOTIFIER:
                ret = blocking_notifier_chain_register(
                                &cpufreq_policy_notifier_list, nb);