diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 2867 |
1 files changed, 2867 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c new file mode 100644 index 000000000..5b4bca71f --- /dev/null +++ b/drivers/cpufreq/cpufreq.c @@ -0,0 +1,2867 @@ +// 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) + +#define for_each_policy(__policy) \ + list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) + +/* 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" + * + * 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 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) +{ + 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); + + spin_lock(&policy->transition_lock); + policy->transition_ongoing = false; + policy->transition_task = NULL; + spin_unlock(&policy->transition_lock); + + 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); + +/** + * 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) +{ + target_freq = clamp_val(target_freq, policy->min, policy->max); + policy->cached_target_freq = target_freq; + + if (cpufreq_driver->target_index) { + unsigned int idx; + + idx = cpufreq_frequency_table_target(policy, target_freq, + CPUFREQ_RELATION_L); + policy->cached_resolved_idx = idx; + return policy->freq_table[idx].frequency; + } + + if (cpufreq_driver->resolve_freq) + return cpufreq_driver->resolve_freq(policy, target_freq); + + return target_freq; +} +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) +{ + 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; + + init_completion(&policy->kobj_unregister); + ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, + cpufreq_global_kobject, "policy%u", cpu); + if (ret) { + dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret); + /* + * The entire policy object will be freed below, but the extra + * memory allocated for the kobject name needs to be freed by + * releasing the kobject. + */ + kobject_put(&policy->kobj); + goto err_free_real_cpus; + } + + freq_constraints_init(&policy->constraints); + + policy->nb_min.notifier_call = cpufreq_notifier_min; + policy->nb_max.notifier_call = cpufreq_notifier_max; + + ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN, + &policy->nb_min); + if (ret) { + dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n", + ret, cpumask_pr_args(policy->cpus)); + goto err_kobj_remove; + } + + ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX, + &policy->nb_max); + if (ret) { + dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n", + ret, cpumask_pr_args(policy->cpus)); + goto err_min_qos_notifier; + } + + INIT_LIST_HEAD(&policy->policy_list); + init_rwsem(&policy->rwsem); + spin_lock_init(&policy->transition_lock); + init_waitqueue_head(&policy->transition_wait); + INIT_WORK(&policy->update, handle_update); + + policy->cpu = cpu; + return policy; + +err_min_qos_notifier: + freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, + &policy->nb_min); +err_kobj_remove: + cpufreq_policy_put_kobj(policy); +err_free_real_cpus: + free_cpumask_var(policy->real_cpus); +err_free_rcpumask: + free_cpumask_var(policy->related_cpus); +err_free_cpumask: + free_cpumask_var(policy->cpus); +err_free_policy: + kfree(policy); + + return NULL; +} + +static void cpufreq_policy_free(struct cpufreq_policy *policy) +{ + unsigned long flags; + int cpu; + + /* 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, get_cpu_device(j)); + } + + policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req), + GFP_KERNEL); + if (!policy->min_freq_req) + goto out_destroy_policy; + + ret = freq_qos_add_request(&policy->constraints, + policy->min_freq_req, FREQ_QOS_MIN, + FREQ_QOS_MIN_DEFAULT_VALUE); + if (ret < 0) { + /* + * So we don't call freq_qos_remove_request() for an + * uninitialized request. + */ + kfree(policy->min_freq_req); + policy->min_freq_req = NULL; + goto out_destroy_policy; + } + + /* + * This must be initialized right here to avoid calling + * freq_qos_remove_request() on uninitialized request in case + * of errors. + */ + policy->max_freq_req = policy->min_freq_req + 1; + + ret = freq_qos_add_request(&policy->constraints, + policy->max_freq_req, FREQ_QOS_MAX, + FREQ_QOS_MAX_DEFAULT_VALUE); + if (ret < 0) { + policy->max_freq_req = NULL; + goto out_destroy_policy; + } + + blocking_notifier_call_chain(&cpufreq_policy_notifier_list, + CPUFREQ_CREATE_POLICY, policy); + } + + if (cpufreq_driver->get && has_target()) { + policy->cur = cpufreq_driver->get(policy->cpu); + if (!policy->cur) { + 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, dev); + + 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 (cpufreq_driver->stop_cpu) + cpufreq_driver->stop_cpu(policy); + + 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 - If actual and saved CPU frequency differs, we're + * in deep trouble. + * @policy: policy managing CPUs + * @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(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 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); + +/** + * cpufreq_get_driver_data - return current driver data + * + * Return the private data of the currently loaded cpufreq + * driver, or NULL if no cpufreq driver is loaded. + */ +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 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; + + switch (list) { + case CPUFREQ_TRANSITION_NOTIFIER: + mutex_lock(&cpufreq_fast_switch_lock); + + if (cpufreq_fast_switch_count > 0) { + mutex_unlock(&cpufreq_fast_switch_lock); + return -EBUSY; + } + ret = srcu_notifier_chain_register( + &cpufreq_transition_notifier_list, nb); + if (!ret) + cpufreq_fast_switch_count--; + + mutex_unlock(&cpufreq_fast_switch_lock); + break; + case CPUFREQ_POLICY_NOTIFIER: + ret = blocking_notifier_chain_register( + &cpufreq_policy_notifier_list, nb); + break; + default: + ret = -EINVAL; + } + + return ret; +} +EXPORT_SYMBOL(cpufreq_register_notifier); + +/** + * cpufreq_unregister_notifier - unregister a 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: + mutex_lock(&cpufreq_fast_switch_lock); + + ret = srcu_notifier_chain_unregister( + &cpufreq_transition_notifier_list, nb); + if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0)) + cpufreq_fast_switch_count++; + + mutex_unlock(&cpufreq_fast_switch_lock); + break; + case CPUFREQ_POLICY_NOTIFIER: + ret = blocking_notifier_chain_unregister( + &cpufreq_policy_notifier_list, nb); + break; + default: + ret = -EINVAL; + } + + return ret; +} +EXPORT_SYMBOL(cpufreq_unregister_notifier); + + +/********************************************************************* + * GOVERNORS * + *********************************************************************/ + +/** + * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch. + * @policy: cpufreq policy to switch the frequency for. + * @target_freq: New frequency to set (may be approximate). + * + * Carry out a fast frequency switch without sleeping. + * + * The driver's ->fast_switch() callback invoked by this function must be + * suitable for being called from within RCU-sched read-side critical sections + * and it is expected to select the minimum available frequency greater than or + * equal to @target_freq (CPUFREQ_RELATION_L). + * + * This function must not be called if policy->fast_switch_enabled is unset. + * + * Governors calling this function must guarantee that it will never be invoked + * twice in parallel for the same policy and that it will never be called in + * parallel with either ->target() or ->target_index() for the same policy. + * + * Returns the actual frequency set for the CPU. + * + * If 0 is returned by the driver's ->fast_switch() callback to indicate an + * error condition, the hardware configuration must be preserved. + */ +unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + unsigned int freq; + int cpu; + + target_freq = clamp_val(target_freq, policy->min, policy->max); + freq = cpufreq_driver->fast_switch(policy, target_freq); + + if (!freq) + return 0; + + policy->cur = freq; + arch_set_freq_scale(policy->related_cpus, freq, + policy->cpuinfo.max_freq); + cpufreq_stats_record_transition(policy, freq); + + if (trace_cpu_frequency_enabled()) { + for_each_cpu(cpu, policy->cpus) + trace_cpu_frequency(freq, cpu); + } + + return freq; +} +EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch); + +/* Must set freqs->new to intermediate frequency */ +static int __target_intermediate(struct cpufreq_policy *policy, + struct cpufreq_freqs *freqs, int index) +{ + int ret; + + freqs->new = cpufreq_driver->get_intermediate(policy, index); + + /* We don't need to switch to intermediate freq */ + if (!freqs->new) + return 0; + + pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", + __func__, policy->cpu, freqs->old, freqs->new); + + cpufreq_freq_transition_begin(policy, freqs); + ret = cpufreq_driver->target_intermediate(policy, index); + cpufreq_freq_transition_end(policy, freqs, ret); + + if (ret) + pr_err("%s: Failed to change to intermediate frequency: %d\n", + __func__, ret); + + return ret; +} + +static int __target_index(struct cpufreq_policy *policy, int index) +{ + struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; + unsigned int intermediate_freq = 0; + unsigned int newfreq = policy->freq_table[index].frequency; + int retval = -EINVAL; + bool notify; + + if (newfreq == policy->cur) + return 0; + + notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); + if (notify) { + /* Handle switching to intermediate frequency */ + if (cpufreq_driver->get_intermediate) { + retval = __target_intermediate(policy, &freqs, index); + if (retval) + return retval; + + intermediate_freq = freqs.new; + /* Set old freq to intermediate */ + if (intermediate_freq) + freqs.old = freqs.new; + } + + freqs.new = newfreq; + pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", + __func__, policy->cpu, freqs.old, freqs.new); + + cpufreq_freq_transition_begin(policy, &freqs); + } + + retval = cpufreq_driver->target_index(policy, index); + if (retval) + pr_err("%s: Failed to change cpu frequency: %d\n", __func__, + retval); + + if (notify) { + cpufreq_freq_transition_end(policy, &freqs, retval); + + /* + * Failed after setting to intermediate freq? Driver should have + * reverted back to initial frequency and so should we. Check + * here for intermediate_freq instead of get_intermediate, in + * case we haven't switched to intermediate freq at all. + */ + if (unlikely(retval && intermediate_freq)) { + freqs.old = intermediate_freq; + freqs.new = 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 index; + + if (cpufreq_disabled()) + return -ENODEV; + + /* Make sure that target_freq is within supported range */ + target_freq = clamp_val(target_freq, policy->min, policy->max); + + pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", + policy->cpu, target_freq, relation, old_target_freq); + + /* + * This might look like a redundant call as we are checking it again + * after finding index. But it is left intentionally for cases where + * exactly same freq is called again and so we can save on few function + * calls. + */ + if (target_freq == policy->cur && + !(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS)) + return 0; + + /* Save last value to restore later on errors */ + policy->restore_freq = policy->cur; + + if (cpufreq_driver->target) + return cpufreq_driver->target(policy, target_freq, relation); + + if (!cpufreq_driver->target_index) + return -EINVAL; + + index = cpufreq_frequency_table_target(policy, target_freq, relation); + + return __target_index(policy, index); +} +EXPORT_SYMBOL_GPL(__cpufreq_driver_target); + +int cpufreq_driver_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + int ret; + + down_write(&policy->rwsem); + + ret = __cpufreq_driver_target(policy, target_freq, relation); + + up_write(&policy->rwsem); + + return ret; +} +EXPORT_SYMBOL_GPL(cpufreq_driver_target); + +__weak struct cpufreq_governor *cpufreq_fallback_governor(void) +{ + return NULL; +} + +static int cpufreq_init_governor(struct cpufreq_policy *policy) +{ + int ret; + + /* Don't start any governor operations if we are entering suspend */ + if (cpufreq_suspended) + return 0; + /* + * Governor might not be initiated here if ACPI _PPC changed + * notification happened, so check it. + */ + if (!policy->governor) + return -EINVAL; + + /* Platform doesn't want dynamic frequency switching ? */ + if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING && + cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) { + struct cpufreq_governor *gov = cpufreq_fallback_governor(); + + if (gov) { + pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n", + policy->governor->name, gov->name); + policy->governor = gov; + } else { + return -EINVAL; + } + } + + if (!try_module_get(policy->governor->owner)) + return -EINVAL; + + pr_debug("%s: for CPU %u\n", __func__, policy->cpu); + + if (policy->governor->init) { + ret = policy->governor->init(policy); + if (ret) { + module_put(policy->governor->owner); + return ret; + } + } + + policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET); + + return 0; +} + +static void cpufreq_exit_governor(struct cpufreq_policy *policy) +{ + if (cpufreq_suspended || !policy->governor) + return; + + pr_debug("%s: for CPU %u\n", __func__, policy->cpu); + + if (policy->governor->exit) + policy->governor->exit(policy); + + module_put(policy->governor->owner); +} + +int cpufreq_start_governor(struct cpufreq_policy *policy) +{ + int ret; + + if (cpufreq_suspended) + return 0; + + if (!policy->governor) + return -EINVAL; + + pr_debug("%s: for CPU %u\n", __func__, policy->cpu); + + if (cpufreq_driver->get) + cpufreq_verify_current_freq(policy, false); + + if (policy->governor->start) { + ret = policy->governor->start(policy); + if (ret) + return ret; + } + + if (policy->governor->limits) + policy->governor->limits(policy); + + return 0; +} + +void cpufreq_stop_governor(struct cpufreq_policy *policy) +{ + if (cpufreq_suspended || !policy->governor) + return; + + pr_debug("%s: for CPU %u\n", __func__, policy->cpu); + + if (policy->governor->stop) + policy->governor->stop(policy); +} + +static void cpufreq_governor_limits(struct cpufreq_policy *policy) +{ + if (cpufreq_suspended || !policy->governor) + return; + + pr_debug("%s: for CPU %u\n", __func__, policy->cpu); + + if (policy->governor->limits) + policy->governor->limits(policy); +} + +int cpufreq_register_governor(struct cpufreq_governor *governor) +{ + int err; + + if (!governor) + return -EINVAL; + + if (cpufreq_disabled()) + return -ENODEV; + + mutex_lock(&cpufreq_governor_mutex); + + err = -EBUSY; + if (!find_governor(governor->name)) { + err = 0; + list_add(&governor->governor_list, &cpufreq_governor_list); + } + + mutex_unlock(&cpufreq_governor_mutex); + return err; +} +EXPORT_SYMBOL_GPL(cpufreq_register_governor); + +void cpufreq_unregister_governor(struct cpufreq_governor *governor) +{ + struct cpufreq_policy *policy; + unsigned long flags; + + if (!governor) + return; + + if (cpufreq_disabled()) + return; + + /* clear last_governor for all inactive policies */ + read_lock_irqsave(&cpufreq_driver_lock, flags); + for_each_inactive_policy(policy) { + if (!strcmp(policy->last_governor, governor->name)) { + policy->governor = NULL; + strcpy(policy->last_governor, "\0"); + } + } + read_unlock_irqrestore(&cpufreq_driver_lock, flags); + + mutex_lock(&cpufreq_governor_mutex); + list_del(&governor->governor_list); + mutex_unlock(&cpufreq_governor_mutex); +} +EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); + + +/********************************************************************* + * POLICY INTERFACE * + *********************************************************************/ + +/** + * cpufreq_get_policy - get the current cpufreq_policy + * @policy: struct cpufreq_policy into which the current cpufreq_policy + * is written + * @cpu: CPU to find the policy for + * + * Reads the current cpufreq policy. + */ +int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) +{ + struct cpufreq_policy *cpu_policy; + if (!policy) + return -EINVAL; + + cpu_policy = cpufreq_cpu_get(cpu); + if (!cpu_policy) + return -EINVAL; + + memcpy(policy, cpu_policy, sizeof(*policy)); + + cpufreq_cpu_put(cpu_policy); + return 0; +} +EXPORT_SYMBOL(cpufreq_get_policy); + +/** + * cpufreq_set_policy - Modify cpufreq policy parameters. + * @policy: Policy object to modify. + * @new_gov: Policy governor pointer. + * @new_pol: Policy value (for drivers with built-in governors). + * + * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency + * limits to be set for the policy, update @policy with the verified limits + * values and either invoke the driver's ->setpolicy() callback (if present) or + * carry out a governor update for @policy. That is, run the current governor's + * ->limits() callback (if @new_gov points to the same object as the one in + * @policy) or replace the governor for @policy with @new_gov. + * + * The cpuinfo part of @policy is not updated by this function. + */ +static int cpufreq_set_policy(struct cpufreq_policy *policy, + struct cpufreq_governor *new_gov, + unsigned int new_pol) +{ + struct cpufreq_policy_data new_data; + struct cpufreq_governor *old_gov; + int ret; + + memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); + new_data.freq_table = policy->freq_table; + new_data.cpu = policy->cpu; + /* + * PM QoS framework collects all the requests from users and provide us + * the final aggregated value here. + */ + new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN); + new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX); + + pr_debug("setting new policy for CPU %u: %u - %u kHz\n", + new_data.cpu, new_data.min, new_data.max); + + /* + * Verify that the CPU speed can be set within these limits and make sure + * that min <= max. + */ + ret = cpufreq_driver->verify(&new_data); + if (ret) + return ret; + + policy->min = new_data.min; + policy->max = new_data.max; + trace_cpu_frequency_limits(policy); + + policy->cached_target_freq = UINT_MAX; + + pr_debug("new min and max freqs are %u - %u kHz\n", + policy->min, policy->max); + + if (cpufreq_driver->setpolicy) { + policy->policy = new_pol; + pr_debug("setting range\n"); + return cpufreq_driver->setpolicy(policy); + } + + if (new_gov == policy->governor) { + pr_debug("governor limits update\n"); + cpufreq_governor_limits(policy); + return 0; + } + + pr_debug("governor switch\n"); + + /* save old, working values */ + old_gov = policy->governor; + /* end old governor */ + if (old_gov) { + cpufreq_stop_governor(policy); + cpufreq_exit_governor(policy); + } + + /* start new governor */ + policy->governor = new_gov; + ret = cpufreq_init_governor(policy); + if (!ret) { + ret = cpufreq_start_governor(policy); + if (!ret) { + pr_debug("governor change\n"); + sched_cpufreq_governor_change(policy, old_gov); + return 0; + } + cpufreq_exit_governor(policy); + } + + /* new governor failed, so re-start old one */ + pr_debug("starting governor %s failed\n", policy->governor->name); + if (old_gov) { + policy->governor = old_gov; + if (cpufreq_init_governor(policy)) + policy->governor = NULL; + else + cpufreq_start_governor(policy); + } + + return ret; +} + +/** + * cpufreq_update_policy - Re-evaluate an existing cpufreq policy. + * @cpu: CPU to re-evaluate the policy for. + * + * Update the current frequency for the cpufreq policy of @cpu and use + * cpufreq_set_policy() to re-apply the min and max limits, which triggers the + * evaluation of policy notifiers and the cpufreq driver's ->verify() callback + * for the policy in question, among other things. + */ +void cpufreq_update_policy(unsigned int cpu) +{ + struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu); + + if (!policy) + return; + + /* + * BIOS might change freq behind our back + * -> ask driver for current freq and notify governors about a change + */ + if (cpufreq_driver->get && has_target() && + (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false)))) + goto unlock; + + refresh_frequency_limits(policy); + +unlock: + cpufreq_cpu_release(policy); +} +EXPORT_SYMBOL(cpufreq_update_policy); + +/** + * cpufreq_update_limits - Update policy limits for a given CPU. + * @cpu: CPU to update the policy limits for. + * + * Invoke the driver's ->update_limits callback if present or call + * cpufreq_update_policy() for @cpu. + */ +void cpufreq_update_limits(unsigned int cpu) +{ + if (cpufreq_driver->update_limits) + cpufreq_driver->update_limits(cpu); + else + cpufreq_update_policy(cpu); +} +EXPORT_SYMBOL_GPL(cpufreq_update_limits); + +/********************************************************************* + * BOOST * + *********************************************************************/ +static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state) +{ + int ret; + + if (!policy->freq_table) + return -ENXIO; + + ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table); + if (ret) { + pr_err("%s: Policy frequency update failed\n", __func__); + return ret; + } + + ret = freq_qos_update_request(policy->max_freq_req, policy->max); + if (ret < 0) + return ret; + + return 0; +} + +int cpufreq_boost_trigger_state(int state) +{ + struct cpufreq_policy *policy; + unsigned long flags; + int ret = 0; + + if (cpufreq_driver->boost_enabled == state) + return 0; + + write_lock_irqsave(&cpufreq_driver_lock, flags); + cpufreq_driver->boost_enabled = state; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + + get_online_cpus(); + for_each_active_policy(policy) { + ret = cpufreq_driver->set_boost(policy, state); + if (ret) + goto err_reset_state; + } + put_online_cpus(); + + return 0; + +err_reset_state: + put_online_cpus(); + + write_lock_irqsave(&cpufreq_driver_lock, flags); + cpufreq_driver->boost_enabled = !state; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + + pr_err("%s: Cannot %s BOOST\n", + __func__, state ? "enable" : "disable"); + + return ret; +} + +static bool cpufreq_boost_supported(void) +{ + return cpufreq_driver->set_boost; +} + +static int create_boost_sysfs_file(void) +{ + int ret; + + ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr); + if (ret) + pr_err("%s: cannot register global BOOST sysfs file\n", + __func__); + + return ret; +} + +static void remove_boost_sysfs_file(void) +{ + if (cpufreq_boost_supported()) + sysfs_remove_file(cpufreq_global_kobject, &boost.attr); +} + +int cpufreq_enable_boost_support(void) +{ + if (!cpufreq_driver) + return -EINVAL; + + if (cpufreq_boost_supported()) + return 0; + + cpufreq_driver->set_boost = cpufreq_boost_set_sw; + + /* This will get removed on driver unregister */ + return create_boost_sysfs_file(); +} +EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support); + +int cpufreq_boost_enabled(void) +{ + return cpufreq_driver->boost_enabled; +} +EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); + +/********************************************************************* + * REGISTER / UNREGISTER CPUFREQ DRIVER * + *********************************************************************/ +static enum cpuhp_state hp_online; + +static int cpuhp_cpufreq_online(unsigned int cpu) +{ + cpufreq_online(cpu); + + return 0; +} + +static int cpuhp_cpufreq_offline(unsigned int cpu) +{ + cpufreq_offline(cpu); + + return 0; +} + +/** + * cpufreq_register_driver - register a CPU Frequency driver + * @driver_data: A struct cpufreq_driver containing the values# + * submitted by the CPU Frequency driver. + * + * Registers a CPU Frequency driver to this core code. This code + * returns zero on success, -EEXIST when another driver got here first + * (and isn't unregistered in the meantime). + * + */ +int cpufreq_register_driver(struct cpufreq_driver *driver_data) +{ + unsigned long flags; + int ret; + + if (cpufreq_disabled()) + return -ENODEV; + + /* + * The cpufreq core depends heavily on the availability of device + * structure, make sure they are available before proceeding further. + */ + if (!get_cpu_device(0)) + return -EPROBE_DEFER; + + if (!driver_data || !driver_data->verify || !driver_data->init || + !(driver_data->setpolicy || driver_data->target_index || + driver_data->target) || + (driver_data->setpolicy && (driver_data->target_index || + driver_data->target)) || + (!driver_data->get_intermediate != !driver_data->target_intermediate) || + (!driver_data->online != !driver_data->offline)) + return -EINVAL; + + pr_debug("trying to register driver %s\n", driver_data->name); + + /* Protect against concurrent CPU online/offline. */ + cpus_read_lock(); + + write_lock_irqsave(&cpufreq_driver_lock, flags); + if (cpufreq_driver) { + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + ret = -EEXIST; + goto out; + } + cpufreq_driver = driver_data; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + + /* + * Mark support for the scheduler's frequency invariance engine for + * drivers that implement target(), target_index() or fast_switch(). + */ + if (!cpufreq_driver->setpolicy) { + static_branch_enable_cpuslocked(&cpufreq_freq_invariance); + pr_debug("supports frequency invariance"); + } + + if (driver_data->setpolicy) + driver_data->flags |= CPUFREQ_CONST_LOOPS; + + if (cpufreq_boost_supported()) { + ret = create_boost_sysfs_file(); + if (ret) + goto err_null_driver; + } + + ret = subsys_interface_register(&cpufreq_interface); + if (ret) + goto err_boost_unreg; + + if (!(cpufreq_driver->flags & CPUFREQ_STICKY) && + list_empty(&cpufreq_policy_list)) { + /* if all ->init() calls failed, unregister */ + ret = -ENODEV; + pr_debug("%s: No CPU initialized for driver %s\n", __func__, + driver_data->name); + goto err_if_unreg; + } + + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, + "cpufreq:online", + cpuhp_cpufreq_online, + cpuhp_cpufreq_offline); + if (ret < 0) + goto err_if_unreg; + hp_online = ret; + ret = 0; + + pr_debug("driver %s up and running\n", driver_data->name); + goto out; + +err_if_unreg: + subsys_interface_unregister(&cpufreq_interface); +err_boost_unreg: + remove_boost_sysfs_file(); +err_null_driver: + write_lock_irqsave(&cpufreq_driver_lock, flags); + cpufreq_driver = NULL; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); +out: + cpus_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(cpufreq_register_driver); + +/* + * cpufreq_unregister_driver - unregister the current CPUFreq driver + * + * Unregister the current CPUFreq driver. Only call this if you have + * the right to do so, i.e. if you have succeeded in initialising before! + * Returns zero if successful, and -EINVAL if the cpufreq_driver is + * currently not initialised. + */ +int cpufreq_unregister_driver(struct cpufreq_driver *driver) +{ + unsigned long flags; + + if (!cpufreq_driver || (driver != cpufreq_driver)) + return -EINVAL; + + pr_debug("unregistering driver %s\n", driver->name); + + /* Protect against concurrent cpu hotplug */ + cpus_read_lock(); + subsys_interface_unregister(&cpufreq_interface); + remove_boost_sysfs_file(); + static_branch_disable_cpuslocked(&cpufreq_freq_invariance); + cpuhp_remove_state_nocalls_cpuslocked(hp_online); + + write_lock_irqsave(&cpufreq_driver_lock, flags); + + cpufreq_driver = NULL; + + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + cpus_read_unlock(); + + return 0; +} +EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); + +static int __init cpufreq_core_init(void) +{ + struct cpufreq_governor *gov = cpufreq_default_governor(); + + if (cpufreq_disabled()) + return -ENODEV; + + cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj); + BUG_ON(!cpufreq_global_kobject); + + if (!strlen(default_governor)) + strncpy(default_governor, gov->name, CPUFREQ_NAME_LEN); + + return 0; +} +module_param(off, int, 0444); +module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444); +core_initcall(cpufreq_core_init); |