/* * linux/drivers/cpufreq/cpufreq.c * * Copyright (C) 2001 Russell King * (C) 2002 - 2003 Dominik Brodowski * (C) 2013 Viresh Kumar * * Oct 2005 - Ashok Raj * Added handling for CPU hotplug * Feb 2006 - Jacob Shin * Fix handling for CPU hotplug -- affected CPUs * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include static LIST_HEAD(cpufreq_policy_list); static inline bool policy_is_inactive(struct cpufreq_policy *policy) { return cpumask_empty(policy->cpus); } static bool suitable_policy(struct cpufreq_policy *policy, bool active) { return active == !policy_is_inactive(policy); } /* Finds Next Acive/Inactive policy */ static struct cpufreq_policy *next_policy(struct cpufreq_policy *policy, bool active) { do { policy = list_next_entry(policy, policy_list); /* No more policies in the list */ if (&policy->policy_list == &cpufreq_policy_list) return NULL; } while (!suitable_policy(policy, active)); return policy; } static struct cpufreq_policy *first_policy(bool active) { struct cpufreq_policy *policy; /* No policies in the list */ if (list_empty(&cpufreq_policy_list)) return NULL; policy = list_first_entry(&cpufreq_policy_list, typeof(*policy), policy_list); if (!suitable_policy(policy, active)) policy = next_policy(policy, active); return policy; } /* Macros to iterate over CPU policies */ #define for_each_suitable_policy(__policy, __active) \ for (__policy = first_policy(__active); \ __policy; \ __policy = next_policy(__policy, __active)) #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) /** * 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); DEFINE_MUTEX(cpufreq_governor_lock); /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended; static inline bool has_target(void) { return cpufreq_driver->target_index || cpufreq_driver->target; } /* * rwsem to guarantee that cpufreq driver module doesn't unload during critical * sections */ static DECLARE_RWSEM(cpufreq_rwsem); /* internal prototypes */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); static unsigned int __cpufreq_get(struct cpufreq_policy *policy); static void handle_update(struct work_struct *work); /** * Two notifier lists: the "policy" list is involved in the * validation process for a new CPU frequency policy; the * "transition" list for kernel code that needs to handle * changes to devices when the CPU clock speed changes. * The mutex locks both lists. */ static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); static struct srcu_notifier_head cpufreq_transition_notifier_list; static bool init_cpufreq_transition_notifier_list_called; static int __init init_cpufreq_transition_notifier_list(void) { srcu_init_notifier_head(&cpufreq_transition_notifier_list); init_cpufreq_transition_notifier_list_called = true; return 0; } pure_initcall(init_cpufreq_transition_notifier_list); static int off __read_mostly; static int cpufreq_disabled(void) { return off; } void disable_cpufreq(void) { off = 1; } static DEFINE_MUTEX(cpufreq_governor_mutex); bool have_governor_per_policy(void) { return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY); } EXPORT_SYMBOL_GPL(have_governor_per_policy); struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) { if (have_governor_per_policy()) return &policy->kobj; else return cpufreq_global_kobject; } EXPORT_SYMBOL_GPL(get_governor_parent_kobj); static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) { u64 idle_time; u64 cur_wall_time; u64 busy_time; cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; idle_time = cur_wall_time - busy_time; if (wall) *wall = cputime_to_usecs(cur_wall_time); return cputime_to_usecs(idle_time); } u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) { u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); if (idle_time == -1ULL) return get_cpu_idle_time_jiffy(cpu, wall); else if (!io_busy) idle_time += get_cpu_iowait_time_us(cpu, wall); return idle_time; } EXPORT_SYMBOL_GPL(get_cpu_idle_time); /* * This is a generic cpufreq init() routine which can be used by cpufreq * drivers of SMP systems. It will do following: * - validate & show freq table passed * - set policies transition latency * - policy->cpus with all possible CPUs */ int cpufreq_generic_init(struct cpufreq_policy *policy, struct cpufreq_frequency_table *table, unsigned int transition_latency) { int ret; ret = cpufreq_table_validate_and_show(policy, table); if (ret) { pr_err("%s: invalid frequency table: %d\n", __func__, ret); return ret; } policy->cpuinfo.transition_latency = transition_latency; /* * The driver only supports the SMP configuartion where all processors * share the clock and voltage and clock. */ cpumask_setall(policy->cpus); return 0; } EXPORT_SYMBOL_GPL(cpufreq_generic_init); /* Only for cpufreq core internal use */ 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; } 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: returns policy for a cpu and marks it busy. * * @cpu: cpu to find policy for. * * This returns policy for 'cpu', returns NULL if it doesn't exist. * It also increments the kobject reference count to mark it busy and so would * require a corresponding call to cpufreq_cpu_put() to decrement it back. * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be * freed as that depends on the kobj count. * * It also takes a read-lock of 'cpufreq_rwsem' and doesn't put it back if a * valid policy is found. This is done to make sure the driver doesn't get * unregistered while the policy is being used. * * Return: A valid policy on success, otherwise NULL on failure. */ 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; if (!down_read_trylock(&cpufreq_rwsem)) return NULL; /* get the cpufreq driver */ read_lock_irqsave(&cpufreq_driver_lock, flags); if (cpufreq_driver) { /* get the CPU */ policy = cpufreq_cpu_get_raw(cpu); if (policy) kobject_get(&policy->kobj); } read_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!policy) up_read(&cpufreq_rwsem); return policy; } EXPORT_SYMBOL_GPL(cpufreq_cpu_get); /** * cpufreq_cpu_put: Decrements the usage count of a policy * * @policy: policy earlier returned by cpufreq_cpu_get(). * * This decrements the kobject reference count incremented earlier by calling * cpufreq_cpu_get(). * * It also drops the read-lock of 'cpufreq_rwsem' taken at cpufreq_cpu_get(). */ void cpufreq_cpu_put(struct cpufreq_policy *policy) { kobject_put(&policy->kobj); up_read(&cpufreq_rwsem); } EXPORT_SYMBOL_GPL(cpufreq_cpu_put); /********************************************************************* * EXTERNALLY AFFECTING FREQUENCY CHANGES * *********************************************************************/ /** * adjust_jiffies - adjust the system "loops_per_jiffy" * * This function alters the system "loops_per_jiffy" for the clock * speed change. Note that loops_per_jiffy cannot be updated on SMP * systems as each CPU might be scaled differently. So, use the arch * per-CPU loops_per_jiffy value wherever possible. */ 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 } static void __cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state) { BUG_ON(irqs_disabled()); if (cpufreq_disabled()) return; freqs->flags = cpufreq_driver->flags; pr_debug("notification %u of frequency transition to %u kHz\n", state, freqs->new); switch (state) { case CPUFREQ_PRECHANGE: /* detect if the driver reported a value as "old frequency" * which is not equal to what the cpufreq core thinks is * "old frequency". */ if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { if ((policy) && (policy->cpu == freqs->cpu) && (policy->cur) && (policy->cur != freqs->old)) { pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n", freqs->old, policy->cur); freqs->old = policy->cur; } } srcu_notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs); adjust_jiffies(CPUFREQ_PRECHANGE, freqs); break; case CPUFREQ_POSTCHANGE: adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); pr_debug("FREQ: %lu - CPU: %lu\n", (unsigned long)freqs->new, (unsigned long)freqs->cpu); trace_cpu_frequency(freqs->new, freqs->cpu); srcu_notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs); if (likely(policy) && likely(policy->cpu == freqs->cpu)) policy->cur = freqs->new; break; } } /** * cpufreq_notify_transition - call notifier chain and adjust_jiffies * on frequency transition. * * This function calls the transition notifiers and the "adjust_jiffies" * function. It is called twice on all CPU frequency changes that have * external effects. */ static void cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state) { for_each_cpu(freqs->cpu, policy->cpus) __cpufreq_notify_transition(policy, freqs, state); } /* Do post notifications when there are chances that transition has failed */ static void cpufreq_notify_post_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, int transition_failed) { cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); if (!transition_failed) return; swap(freqs->old, freqs->new); cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); } void cpufreq_freq_transition_begin(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs) { /* * Catch double invocations of _begin() which lead to self-deadlock. * ASYNC_NOTIFICATION drivers are left out because the cpufreq core * doesn't invoke _begin() on their behalf, and hence the chances of * double invocations are very low. Moreover, there are scenarios * where these checks can emit false-positive warnings in these * drivers; so we avoid that by skipping them altogether. */ WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION) && current == policy->transition_task); wait: wait_event(policy->transition_wait, !policy->transition_ongoing); spin_lock(&policy->transition_lock); if (unlikely(policy->transition_ongoing)) { spin_unlock(&policy->transition_lock); goto wait; } policy->transition_ongoing = true; policy->transition_task = current; spin_unlock(&policy->transition_lock); cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); } EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); void cpufreq_freq_transition_end(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, int transition_failed) { if (unlikely(WARN_ON(!policy->transition_ongoing))) return; cpufreq_notify_post_transition(policy, freqs, transition_failed); policy->transition_ongoing = false; policy->transition_task = NULL; wake_up(&policy->transition_wait); } EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end); /********************************************************************* * SYSFS INTERFACE * *********************************************************************/ static ssize_t show_boost(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled); } static ssize_t store_boost(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret, enable; ret = sscanf(buf, "%d", &enable); if (ret != 1 || enable < 0 || enable > 1) return -EINVAL; if (cpufreq_boost_trigger_state(enable)) { pr_err("%s: Cannot %s BOOST!\n", __func__, enable ? "enable" : "disable"); return -EINVAL; } pr_debug("%s: cpufreq BOOST %s\n", __func__, enable ? "enabled" : "disabled"); return count; } define_one_global_rw(boost); static struct cpufreq_governor *find_governor(const char *str_governor) { struct cpufreq_governor *t; for_each_governor(t) if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN)) return t; return NULL; } /** * cpufreq_parse_governor - parse a governor string */ static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, struct cpufreq_governor **governor) { int err = -EINVAL; if (!cpufreq_driver) goto out; if (cpufreq_driver->setpolicy) { if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { *policy = CPUFREQ_POLICY_PERFORMANCE; err = 0; } else if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) { *policy = CPUFREQ_POLICY_POWERSAVE; err = 0; } } else { struct cpufreq_governor *t; mutex_lock(&cpufreq_governor_mutex); t = find_governor(str_governor); if (t == NULL) { int ret; mutex_unlock(&cpufreq_governor_mutex); ret = request_module("cpufreq_%s", str_governor); mutex_lock(&cpufreq_governor_mutex); if (ret == 0) t = find_governor(str_governor); } if (t != NULL) { *governor = t; err = 0; } mutex_unlock(&cpufreq_governor_mutex); } out: return err; } /** * cpufreq_per_cpu_attr_read() / show_##file_name() - * print out cpufreq information * * Write out information from cpufreq_driver->policy[cpu]; object must be * "unsigned int". */ #define show_one(file_name, object) \ static ssize_t show_##file_name \ (struct cpufreq_policy *policy, char *buf) \ { \ return sprintf(buf, "%u\n", policy->object); \ } show_one(cpuinfo_min_freq, cpuinfo.min_freq); show_one(cpuinfo_max_freq, cpuinfo.max_freq); show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) { ssize_t ret; if (cpufreq_driver && 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; } static int cpufreq_set_policy(struct cpufreq_policy *policy, struct cpufreq_policy *new_policy); /** * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access */ #define store_one(file_name, object) \ static ssize_t store_##file_name \ (struct cpufreq_policy *policy, const char *buf, size_t count) \ { \ int ret, temp; \ struct cpufreq_policy new_policy; \ \ ret = cpufreq_get_policy(&new_policy, policy->cpu); \ if (ret) \ return -EINVAL; \ \ ret = sscanf(buf, "%u", &new_policy.object); \ if (ret != 1) \ return -EINVAL; \ \ temp = new_policy.object; \ ret = cpufreq_set_policy(policy, &new_policy); \ if (!ret) \ policy->user_policy.object = temp; \ \ return ret ? ret : count; \ } store_one(scaling_min_freq, min); store_one(scaling_max_freq, max); /** * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware */ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, char *buf) { unsigned int cur_freq = __cpufreq_get(policy); if (!cur_freq) return sprintf(buf, ""); return sprintf(buf, "%u\n", cur_freq); } /** * show_scaling_governor - show the current policy for the specified CPU */ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) { if (policy->policy == CPUFREQ_POLICY_POWERSAVE) return sprintf(buf, "powersave\n"); else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) return sprintf(buf, "performance\n"); else if (policy->governor) return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", policy->governor->name); return -EINVAL; } /** * store_scaling_governor - store policy for the specified CPU */ static ssize_t store_scaling_governor(struct cpufreq_policy *policy, const char *buf, size_t count) { int ret; char str_governor[16]; struct cpufreq_policy new_policy; ret = cpufreq_get_policy(&new_policy, policy->cpu); if (ret) return ret; ret = sscanf(buf, "%15s", str_governor); if (ret != 1) return -EINVAL; if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor)) return -EINVAL; ret = cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; if (ret) return ret; else return count; } /** * show_scaling_driver - show the cpufreq driver currently loaded */ static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) { return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); } /** * show_scaling_available_governors - show the available CPUfreq governors */ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, char *buf) { ssize_t i = 0; struct cpufreq_governor *t; if (!has_target()) { i += sprintf(buf, "performance powersave"); goto out; } for_each_governor(t) { if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2))) goto out; i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); } out: i += sprintf(&buf[i], "\n"); return i; } ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) { ssize_t i = 0; unsigned int cpu; for_each_cpu(cpu, mask) { if (i) i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); if (i >= (PAGE_SIZE - 5)) break; } i += sprintf(&buf[i], "\n"); return i; } EXPORT_SYMBOL_GPL(cpufreq_show_cpus); /** * show_related_cpus - show the CPUs affected by each transition even if * hw coordination is in use */ static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) { return cpufreq_show_cpus(policy->related_cpus, buf); } /** * show_affected_cpus - show the CPUs affected by each transition */ static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) { return cpufreq_show_cpus(policy->cpus, buf); } static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, const char *buf, size_t count) { unsigned int freq = 0; unsigned int ret; if (!policy->governor || !policy->governor->store_setspeed) return -EINVAL; ret = sscanf(buf, "%u", &freq); if (ret != 1) return -EINVAL; policy->governor->store_setspeed(policy, freq); return count; } static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) { if (!policy->governor || !policy->governor->show_setspeed) return sprintf(buf, "\n"); return policy->governor->show_setspeed(policy, buf); } /** * show_bios_limit - show the current cpufreq HW/BIOS limitation */ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) { unsigned int limit; int ret; if (cpufreq_driver->bios_limit) { ret = cpufreq_driver->bios_limit(policy->cpu, &limit); if (!ret) return sprintf(buf, "%u\n", limit); } return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); } cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); cpufreq_freq_attr_ro(cpuinfo_min_freq); cpufreq_freq_attr_ro(cpuinfo_max_freq); cpufreq_freq_attr_ro(cpuinfo_transition_latency); cpufreq_freq_attr_ro(scaling_available_governors); cpufreq_freq_attr_ro(scaling_driver); cpufreq_freq_attr_ro(scaling_cur_freq); cpufreq_freq_attr_ro(bios_limit); cpufreq_freq_attr_ro(related_cpus); cpufreq_freq_attr_ro(affected_cpus); cpufreq_freq_attr_rw(scaling_min_freq); cpufreq_freq_attr_rw(scaling_max_freq); cpufreq_freq_attr_rw(scaling_governor); cpufreq_freq_attr_rw(scaling_setspeed); static struct attribute *default_attrs[] = { &cpuinfo_min_freq.attr, &cpuinfo_max_freq.attr, &cpuinfo_transition_latency.attr, &scaling_min_freq.attr, &scaling_max_freq.attr, &affected_cpus.attr, &related_cpus.attr, &scaling_governor.attr, &scaling_driver.attr, &scaling_available_governors.attr, &scaling_setspeed.attr, NULL }; #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) #define to_attr(a) container_of(a, struct freq_attr, attr) static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret; if (!down_read_trylock(&cpufreq_rwsem)) return -EINVAL; down_read(&policy->rwsem); if (fattr->show) ret = fattr->show(policy, buf); else ret = -EIO; up_read(&policy->rwsem); up_read(&cpufreq_rwsem); return ret; } static ssize_t store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; get_online_cpus(); if (!cpu_online(policy->cpu)) goto unlock; if (!down_read_trylock(&cpufreq_rwsem)) goto unlock; down_write(&policy->rwsem); if (fattr->store) ret = fattr->store(policy, buf, count); else ret = -EIO; up_write(&policy->rwsem); up_read(&cpufreq_rwsem); unlock: put_online_cpus(); return ret; } static void cpufreq_sysfs_release(struct kobject *kobj) { struct cpufreq_policy *policy = to_policy(kobj); pr_debug("last reference is dropped\n"); complete(&policy->kobj_unregister); } static const struct sysfs_ops sysfs_ops = { .show = show, .store = store, }; static struct kobj_type ktype_cpufreq = { .sysfs_ops = &sysfs_ops, .default_attrs = default_attrs, .release = cpufreq_sysfs_release, }; struct kobject *cpufreq_global_kobject; EXPORT_SYMBOL(cpufreq_global_kobject); static int cpufreq_global_kobject_usage; int cpufreq_get_global_kobject(void) { if (!cpufreq_global_kobject_usage++) return kobject_add(cpufreq_global_kobject, &cpu_subsys.dev_root->kobj, "%s", "cpufreq"); return 0; } EXPORT_SYMBOL(cpufreq_get_global_kobject); void cpufreq_put_global_kobject(void) { if (!--cpufreq_global_kobject_usage) kobject_del(cpufreq_global_kobject); } EXPORT_SYMBOL(cpufreq_put_global_kobject); int cpufreq_sysfs_create_file(const struct attribute *attr) { int ret = cpufreq_get_global_kobject(); if (!ret) { ret = sysfs_create_file(cpufreq_global_kobject, attr); if (ret) cpufreq_put_global_kobject(); } return ret; } EXPORT_SYMBOL(cpufreq_sysfs_create_file); void cpufreq_sysfs_remove_file(const struct attribute *attr) { sysfs_remove_file(cpufreq_global_kobject, attr); cpufreq_put_global_kobject(); } EXPORT_SYMBOL(cpufreq_sysfs_remove_file); /* symlink affected CPUs */ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) { unsigned int j; int ret = 0; for_each_cpu(j, policy->cpus) { struct device *cpu_dev; if (j == policy->cpu) continue; pr_debug("Adding link for CPU: %u\n", j); cpu_dev = get_cpu_device(j); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); if (ret) break; } return ret; } static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, struct device *dev) { struct freq_attr **drv_attr; int ret = 0; /* 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 cpufreq_add_dev_symlink(policy); } static void cpufreq_init_policy(struct cpufreq_policy *policy) { struct cpufreq_governor *gov = NULL; struct cpufreq_policy new_policy; int ret = 0; memcpy(&new_policy, policy, sizeof(*policy)); /* Update governor of new_policy to the governor used before hotplug */ gov = find_governor(policy->last_governor); if (gov) pr_debug("Restoring governor %s for cpu %d\n", policy->governor->name, policy->cpu); else gov = CPUFREQ_DEFAULT_GOVERNOR; new_policy.governor = gov; /* Use the default policy if its valid. */ if (cpufreq_driver->setpolicy) cpufreq_parse_governor(gov->name, &new_policy.policy, NULL); /* set default policy */ ret = cpufreq_set_policy(policy, &new_policy); if (ret) { pr_debug("setting policy failed\n"); if (cpufreq_driver->exit) cpufreq_driver->exit(policy); } } static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu, struct device *dev) { int ret = 0; /* Has this CPU been taken care of already? */ if (cpumask_test_cpu(cpu, policy->cpus)) return 0; if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) { pr_err("%s: Failed to stop governor\n", __func__); return ret; } } down_write(&policy->rwsem); cpumask_set_cpu(cpu, policy->cpus); up_write(&policy->rwsem); if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); if (!ret) ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); if (ret) { pr_err("%s: Failed to start governor\n", __func__); return ret; } } return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); } static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu) { struct cpufreq_policy *policy; unsigned long flags; read_lock_irqsave(&cpufreq_driver_lock, flags); policy = per_cpu(cpufreq_cpu_data, cpu); read_unlock_irqrestore(&cpufreq_driver_lock, flags); if (likely(policy)) { /* Policy should be inactive here */ WARN_ON(!policy_is_inactive(policy)); } return policy; } static struct cpufreq_policy *cpufreq_policy_alloc(void) { struct cpufreq_policy *policy; policy = kzalloc(sizeof(*policy), GFP_KERNEL); if (!policy) return NULL; if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) goto err_free_policy; if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) goto err_free_cpumask; INIT_LIST_HEAD(&policy->policy_list); init_rwsem(&policy->rwsem); spin_lock_init(&policy->transition_lock); init_waitqueue_head(&policy->transition_wait); init_completion(&policy->kobj_unregister); INIT_WORK(&policy->update, handle_update); return policy; err_free_cpumask: free_cpumask_var(policy->cpus); err_free_policy: kfree(policy); return NULL; } static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy) { struct kobject *kobj; struct completion *cmp; blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_REMOVE_POLICY, policy); down_read(&policy->rwsem); kobj = &policy->kobj; cmp = &policy->kobj_unregister; up_read(&policy->rwsem); kobject_put(kobj); /* * We need to make sure that the underlying kobj is * actually not referenced anymore by anybody before we * proceed with unloading. */ pr_debug("waiting for dropping of refcount\n"); wait_for_completion(cmp); pr_debug("wait complete\n"); } static void cpufreq_policy_free(struct cpufreq_policy *policy) { 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); free_cpumask_var(policy->related_cpus); free_cpumask_var(policy->cpus); kfree(policy); } static int update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu, struct device *cpu_dev) { int ret; if (WARN_ON(cpu == policy->cpu)) return 0; /* Move kobject to the new policy->cpu */ ret = kobject_move(&policy->kobj, &cpu_dev->kobj); if (ret) { pr_err("%s: Failed to move kobj: %d\n", __func__, ret); return ret; } down_write(&policy->rwsem); policy->cpu = cpu; up_write(&policy->rwsem); return 0; } /** * cpufreq_add_dev - add a CPU device * * Adds the cpufreq interface for a CPU device. * * The Oracle says: try running cpufreq registration/unregistration concurrently * with with cpu hotplugging and all hell will break loose. Tried to clean this * mess up, but more thorough testing is needed. - Mathieu */ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) { unsigned int j, cpu = dev->id; int ret = -ENOMEM; struct cpufreq_policy *policy; unsigned long flags; bool recover_policy = cpufreq_suspended; if (cpu_is_offline(cpu)) return 0; pr_debug("adding CPU %u\n", cpu); if (!down_read_trylock(&cpufreq_rwsem)) return 0; /* Check if this CPU already has a policy to manage it */ policy = per_cpu(cpufreq_cpu_data, cpu); if (policy && !policy_is_inactive(policy)) { WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus)); ret = cpufreq_add_policy_cpu(policy, cpu, dev); up_read(&cpufreq_rwsem); return ret; } /* * Restore the saved policy when doing light-weight init and fall back * to the full init if that fails. */ policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL; if (!policy) { recover_policy = false; policy = cpufreq_policy_alloc(); if (!policy) goto nomem_out; } /* * In the resume path, since we restore a saved policy, the assignment * to policy->cpu is like an update of the existing policy, rather than * the creation of a brand new one. So we need to perform this update * by invoking update_policy_cpu(). */ if (recover_policy && cpu != policy->cpu) WARN_ON(update_policy_cpu(policy, cpu, dev)); else policy->cpu = cpu; 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("initialization failed\n"); goto err_set_policy_cpu; } down_write(&policy->rwsem); /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); /* * affected cpus must always be the one, which are online. We aren't * managing offline cpus here. */ cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); if (!recover_policy) { policy->user_policy.min = policy->min; policy->user_policy.max = policy->max; /* prepare interface data */ ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj, "cpufreq"); if (ret) { pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret); goto err_init_policy_kobj; } write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->related_cpus) per_cpu(cpufreq_cpu_data, j) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); } if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { policy->cur = cpufreq_driver->get(policy->cpu); if (!policy->cur) { pr_err("%s: ->get() failed\n", __func__); goto err_get_freq; } } /* * Sometimes boot loaders set CPU frequency to a value outside of * frequency table present with cpufreq core. In such cases CPU might be * unstable if it has to run on that frequency for long duration of time * and so its better to set it to a frequency which is specified in * freq-table. This also makes cpufreq stats inconsistent as * cpufreq-stats would fail to register because current frequency of CPU * isn't found in freq-table. * * Because we don't want this change to effect boot process badly, we go * for the next freq which is >= policy->cur ('cur' must be set by now, * otherwise we will end up setting freq to lowest of the table as 'cur' * is initialized to zero). * * We are passing target-freq as "policy->cur - 1" otherwise * __cpufreq_driver_target() would simply fail, as policy->cur will be * equal to target-freq. */ if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) && has_target()) { /* Are we running at unknown frequency ? */ ret = cpufreq_frequency_table_get_index(policy, policy->cur); if (ret == -EINVAL) { /* Warn user and fix it */ pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", __func__, policy->cpu, policy->cur); ret = __cpufreq_driver_target(policy, policy->cur - 1, CPUFREQ_RELATION_L); /* * Reaching here after boot in a few seconds may not * mean that system will remain stable at "unknown" * frequency for longer duration. Hence, a BUG_ON(). */ BUG_ON(ret); pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", __func__, policy->cpu, policy->cur); } } blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_START, policy); if (!recover_policy) { ret = cpufreq_add_dev_interface(policy, dev); if (ret) goto err_out_unregister; blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_CREATE_POLICY, policy); write_lock_irqsave(&cpufreq_driver_lock, flags); list_add(&policy->policy_list, &cpufreq_policy_list); write_unlock_irqrestore(&cpufreq_driver_lock, flags); } cpufreq_init_policy(policy); if (!recover_policy) { policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; } up_write(&policy->rwsem); kobject_uevent(&policy->kobj, KOBJ_ADD); up_read(&cpufreq_rwsem); /* Callback for handling stuff after policy is ready */ if (cpufreq_driver->ready) cpufreq_driver->ready(policy); pr_debug("initialization complete\n"); return 0; err_out_unregister: err_get_freq: if (!recover_policy) { kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); } err_init_policy_kobj: up_write(&policy->rwsem); if (cpufreq_driver->exit) cpufreq_driver->exit(policy); err_set_policy_cpu: if (recover_policy) cpufreq_policy_put_kobj(policy); cpufreq_policy_free(policy); nomem_out: up_read(&cpufreq_rwsem); return ret; } static int __cpufreq_remove_dev_prepare(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id, cpus; int ret; struct cpufreq_policy *policy; pr_debug("%s: unregistering CPU %u\n", __func__, cpu); policy = cpufreq_cpu_get_raw(cpu); if (!policy) { pr_debug("%s: No cpu_data found\n", __func__); return -EINVAL; } if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) { pr_err("%s: Failed to stop governor\n", __func__); return ret; } } down_write(&policy->rwsem); cpus = cpumask_weight(policy->cpus); if (has_target() && cpus == 1) strncpy(policy->last_governor, policy->governor->name, CPUFREQ_NAME_LEN); up_write(&policy->rwsem); if (cpu != policy->cpu) { sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { /* Nominate new CPU */ int new_cpu = cpumask_any_but(policy->cpus, cpu); struct device *cpu_dev = get_cpu_device(new_cpu); sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); ret = update_policy_cpu(policy, new_cpu, cpu_dev); if (ret) { if (sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq")) pr_err("%s: Failed to restore kobj link to cpu:%d\n", __func__, cpu_dev->id); return ret; } if (!cpufreq_suspended) pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", __func__, new_cpu, cpu); } else if (cpufreq_driver->stop_cpu) { cpufreq_driver->stop_cpu(policy); } return 0; } static int __cpufreq_remove_dev_finish(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; int ret; struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); if (!policy) { pr_debug("%s: No cpu_data found\n", __func__); return -EINVAL; } down_write(&policy->rwsem); cpumask_clear_cpu(cpu, policy->cpus); up_write(&policy->rwsem); /* If cpu is last user of policy, free policy */ if (policy_is_inactive(policy)) { if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); if (ret) { pr_err("%s: Failed to exit governor\n", __func__); return ret; } } if (!cpufreq_suspended) cpufreq_policy_put_kobj(policy); /* * Perform the ->exit() even during light-weight tear-down, * since this is a core component, and is essential for the * subsequent light-weight ->init() to succeed. */ if (cpufreq_driver->exit) cpufreq_driver->exit(policy); if (!cpufreq_suspended) cpufreq_policy_free(policy); } else if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); if (!ret) ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); if (ret) { pr_err("%s: Failed to start governor\n", __func__); return ret; } } return 0; } /** * cpufreq_remove_dev - remove a CPU device * * Removes the cpufreq interface for a CPU device. */ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; int ret; if (cpu_is_offline(cpu)) return 0; ret = __cpufreq_remove_dev_prepare(dev, sif); if (!ret) ret = __cpufreq_remove_dev_finish(dev, sif); return ret; } static void handle_update(struct work_struct *work) { struct cpufreq_policy *policy = container_of(work, struct cpufreq_policy, update); unsigned int cpu = policy->cpu; pr_debug("handle_update for cpu %u called\n", cpu); cpufreq_update_policy(cpu); } /** * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're * in deep trouble. * @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); } /** * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur * @cpu: CPU number * * This is the last known freq, without actually getting it from the driver. * Return value will be same as what is shown in scaling_cur_freq in sysfs. */ unsigned int cpufreq_quick_get(unsigned int cpu) { struct cpufreq_policy *policy; unsigned int ret_freq = 0; if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) return cpufreq_driver->get(cpu); policy = cpufreq_cpu_get(cpu); if (policy) { ret_freq = policy->cur; cpufreq_cpu_put(policy); } return ret_freq; } EXPORT_SYMBOL(cpufreq_quick_get); /** * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU * @cpu: CPU number * * Just return the max possible frequency for a given CPU. */ unsigned int cpufreq_quick_get_max(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); unsigned int ret_freq = 0; if (policy) { ret_freq = policy->max; cpufreq_cpu_put(policy); } return ret_freq; } EXPORT_SYMBOL(cpufreq_quick_get_max); static unsigned int __cpufreq_get(struct cpufreq_policy *policy) { unsigned int ret_freq = 0; if (!cpufreq_driver->get) return ret_freq; ret_freq = cpufreq_driver->get(policy->cpu); if (ret_freq && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { /* verify no discrepancy between actual and saved value exists */ if (unlikely(ret_freq != policy->cur)) { cpufreq_out_of_sync(policy, ret_freq); schedule_work(&policy->update); } } return ret_freq; } /** * cpufreq_get - get the current CPU frequency (in kHz) * @cpu: CPU number * * Get the CPU current (static) CPU frequency */ unsigned int cpufreq_get(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); unsigned int ret_freq = 0; if (policy) { down_read(&policy->rwsem); ret_freq = __cpufreq_get(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_err("%s: suspend_freq can't be zero\n", __func__); return -EINVAL; } pr_debug("%s: Setting suspend-freq: %u\n", __func__, policy->suspend_freq); ret = __cpufreq_driver_target(policy, policy->suspend_freq, CPUFREQ_RELATION_H); if (ret) pr_err("%s: unable to set suspend-freq: %u. err: %d\n", __func__, policy->suspend_freq, ret); return ret; } EXPORT_SYMBOL(cpufreq_generic_suspend); /** * cpufreq_suspend() - Suspend CPUFreq governors * * Called during system wide Suspend/Hibernate cycles for suspending governors * as some platforms can't change frequency after this point in suspend cycle. * Because some of the devices (like: i2c, regulators, etc) they use for * changing frequency are suspended quickly after this point. */ void cpufreq_suspend(void) { struct cpufreq_policy *policy; if (!cpufreq_driver) return; if (!has_target()) goto suspend; pr_debug("%s: Suspending Governors\n", __func__); for_each_active_policy(policy) { if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP)) pr_err("%s: Failed to stop governor for policy: %p\n", __func__, policy); else if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy)) pr_err("%s: Failed to suspend driver: %p\n", __func__, policy); } 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; if (!cpufreq_driver) return; cpufreq_suspended = false; if (!has_target()) 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 (__cpufreq_governor(policy, CPUFREQ_GOV_START) || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS)) pr_err("%s: Failed to start governor for policy: %p\n", __func__, policy); } /* * schedule call cpufreq_update_policy() for first-online CPU, as that * wouldn't be hotplugged-out on suspend. It will verify that the * current freq is in sync with what we believe it to be. */ policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask)); if (WARN_ON(!policy)) return; schedule_work(&policy->update); } /** * cpufreq_get_current_driver - return current driver's name * * Return the name string of the currently loaded cpufreq driver * or NULL, if none. */ const char *cpufreq_get_current_driver(void) { if (cpufreq_driver) return cpufreq_driver->name; return NULL; } EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); /** * 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; WARN_ON(!init_cpufreq_transition_notifier_list_called); switch (list) { case CPUFREQ_TRANSITION_NOTIFIER: ret = srcu_notifier_chain_register( &cpufreq_transition_notifier_list, nb); break; case CPUFREQ_POLICY_NOTIFIER: ret = blocking_notifier_chain_register( &cpufreq_policy_notifier_list, nb); break; default: ret = -EINVAL; } return ret; } EXPORT_SYMBOL(cpufreq_register_notifier); /** * cpufreq_unregister_notifier - unregister a driver with cpufreq * @nb: notifier block to be unregistered * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER * * Remove a driver from the CPU frequency notifier list. * * This function may sleep, and has the same return conditions as * blocking_notifier_chain_unregister. */ int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) { int ret; if (cpufreq_disabled()) return -EINVAL; switch (list) { case CPUFREQ_TRANSITION_NOTIFIER: ret = srcu_notifier_chain_unregister( &cpufreq_transition_notifier_list, nb); break; case CPUFREQ_POLICY_NOTIFIER: ret = blocking_notifier_chain_unregister( &cpufreq_policy_notifier_list, nb); break; default: ret = -EINVAL; } return ret; } EXPORT_SYMBOL(cpufreq_unregister_notifier); /********************************************************************* * GOVERNORS * *********************************************************************/ /* Must set freqs->new to intermediate frequency */ static int __target_intermediate(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, int index) { int ret; freqs->new = cpufreq_driver->get_intermediate(policy, index); /* We don't need to switch to intermediate freq */ if (!freqs->new) return 0; pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", __func__, policy->cpu, freqs->old, freqs->new); cpufreq_freq_transition_begin(policy, freqs); ret = cpufreq_driver->target_intermediate(policy, index); cpufreq_freq_transition_end(policy, freqs, ret); if (ret) pr_err("%s: Failed to change to intermediate frequency: %d\n", __func__, ret); return ret; } static int __target_index(struct cpufreq_policy *policy, struct cpufreq_frequency_table *freq_table, int index) { struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; unsigned int intermediate_freq = 0; int retval = -EINVAL; bool notify; notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); if (notify) { /* Handle switching to intermediate frequency */ if (cpufreq_driver->get_intermediate) { retval = __target_intermediate(policy, &freqs, index); if (retval) return retval; intermediate_freq = freqs.new; /* Set old freq to intermediate */ if (intermediate_freq) freqs.old = freqs.new; } freqs.new = freq_table[index].frequency; pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", __func__, policy->cpu, freqs.old, freqs.new); cpufreq_freq_transition_begin(policy, &freqs); } retval = cpufreq_driver->target_index(policy, index); if (retval) pr_err("%s: Failed to change cpu frequency: %d\n", __func__, retval); if (notify) { cpufreq_freq_transition_end(policy, &freqs, retval); /* * Failed after setting to intermediate freq? Driver should have * reverted back to initial frequency and so should we. Check * here for intermediate_freq instead of get_intermediate, in * case we have't switched to intermediate freq at all. */ if (unlikely(retval && intermediate_freq)) { freqs.old = intermediate_freq; freqs.new = policy->restore_freq; cpufreq_freq_transition_begin(policy, &freqs); cpufreq_freq_transition_end(policy, &freqs, 0); } } return retval; } int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { unsigned int old_target_freq = target_freq; int retval = -EINVAL; if (cpufreq_disabled()) return -ENODEV; /* Make sure that target_freq is within supported range */ if (target_freq > policy->max) target_freq = policy->max; if (target_freq < policy->min) target_freq = policy->min; pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", policy->cpu, target_freq, relation, old_target_freq); /* * This might look like a redundant call as we are checking it again * after finding index. But it is left intentionally for cases where * exactly same freq is called again and so we can save on few function * calls. */ if (target_freq == policy->cur) return 0; /* Save last value to restore later on errors */ policy->restore_freq = policy->cur; if (cpufreq_driver->target) retval = cpufreq_driver->target(policy, target_freq, relation); else if (cpufreq_driver->target_index) { struct cpufreq_frequency_table *freq_table; int index; freq_table = cpufreq_frequency_get_table(policy->cpu); if (unlikely(!freq_table)) { pr_err("%s: Unable to find freq_table\n", __func__); goto out; } retval = cpufreq_frequency_table_target(policy, freq_table, target_freq, relation, &index); if (unlikely(retval)) { pr_err("%s: Unable to find matching freq\n", __func__); goto out; } if (freq_table[index].frequency == policy->cur) { retval = 0; goto out; } retval = __target_index(policy, freq_table, index); } out: return retval; } EXPORT_SYMBOL_GPL(__cpufreq_driver_target); int cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int ret = -EINVAL; down_write(&policy->rwsem); ret = __cpufreq_driver_target(policy, target_freq, relation); up_write(&policy->rwsem); return ret; } EXPORT_SYMBOL_GPL(cpufreq_driver_target); static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event) { int ret; /* Only must be defined when default governor is known to have latency restrictions, like e.g. conservative or ondemand. That this is the case is already ensured in Kconfig */ #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE struct cpufreq_governor *gov = &cpufreq_gov_performance; #else struct cpufreq_governor *gov = NULL; #endif /* Don't start any governor operations if we are entering suspend */ if (cpufreq_suspended) return 0; /* * Governor might not be initiated here if ACPI _PPC changed * notification happened, so check it. */ if (!policy->governor) return -EINVAL; if (policy->governor->max_transition_latency && policy->cpuinfo.transition_latency > policy->governor->max_transition_latency) { if (!gov) return -EINVAL; else { pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", policy->governor->name, gov->name); policy->governor = gov; } } if (event == CPUFREQ_GOV_POLICY_INIT) if (!try_module_get(policy->governor->owner)) return -EINVAL; pr_debug("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event); mutex_lock(&cpufreq_governor_lock); if ((policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { mutex_unlock(&cpufreq_governor_lock); return -EBUSY; } if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = false; else if (event == CPUFREQ_GOV_START) policy->governor_enabled = true; mutex_unlock(&cpufreq_governor_lock); ret = policy->governor->governor(policy, event); if (!ret) { if (event == CPUFREQ_GOV_POLICY_INIT) policy->governor->initialized++; else if (event == CPUFREQ_GOV_POLICY_EXIT) policy->governor->initialized--; } else { /* Restore original values */ mutex_lock(&cpufreq_governor_lock); if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = true; else if (event == CPUFREQ_GOV_START) policy->governor_enabled = false; mutex_unlock(&cpufreq_governor_lock); } if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) module_put(policy->governor->owner); return ret; } int cpufreq_register_governor(struct cpufreq_governor *governor) { int err; if (!governor) return -EINVAL; if (cpufreq_disabled()) return -ENODEV; mutex_lock(&cpufreq_governor_mutex); governor->initialized = 0; err = -EBUSY; if (!find_governor(governor->name)) { 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); return; } EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); /********************************************************************* * POLICY INTERFACE * *********************************************************************/ /** * cpufreq_get_policy - get the current cpufreq_policy * @policy: struct cpufreq_policy into which the current cpufreq_policy * is written * * Reads the current cpufreq policy. */ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) { struct cpufreq_policy *cpu_policy; if (!policy) return -EINVAL; cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return -EINVAL; memcpy(policy, cpu_policy, sizeof(*policy)); cpufreq_cpu_put(cpu_policy); return 0; } EXPORT_SYMBOL(cpufreq_get_policy); /* * policy : current policy. * new_policy: policy to be set. */ static int cpufreq_set_policy(struct cpufreq_policy *policy, struct cpufreq_policy *new_policy) { struct cpufreq_governor *old_gov; int ret; pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu, new_policy->min, new_policy->max); memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); if (new_policy->min > policy->max || new_policy->max < policy->min) return -EINVAL; /* verify the cpu speed can be set within this limit */ ret = cpufreq_driver->verify(new_policy); if (ret) return ret; /* adjust if necessary - all reasons */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST, new_policy); /* adjust if necessary - hardware incompatibility*/ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE, new_policy); /* * verify the cpu speed can be set within this limit, which might be * different to the first one */ ret = cpufreq_driver->verify(new_policy); if (ret) return ret; /* notification of the new policy */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY, new_policy); policy->min = new_policy->min; policy->max = new_policy->max; pr_debug("new min and max freqs are %u - %u kHz\n", policy->min, policy->max); if (cpufreq_driver->setpolicy) { policy->policy = new_policy->policy; pr_debug("setting range\n"); return cpufreq_driver->setpolicy(new_policy); } if (new_policy->governor == policy->governor) goto out; pr_debug("governor switch\n"); /* save old, working values */ old_gov = policy->governor; /* end old governor */ if (old_gov) { __cpufreq_governor(policy, CPUFREQ_GOV_STOP); up_write(&policy->rwsem); __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); down_write(&policy->rwsem); } /* start new governor */ policy->governor = new_policy->governor; if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) goto out; up_write(&policy->rwsem); __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); down_write(&policy->rwsem); } /* new governor failed, so re-start old one */ pr_debug("starting governor %s failed\n", policy->governor->name); if (old_gov) { policy->governor = old_gov; __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); __cpufreq_governor(policy, CPUFREQ_GOV_START); } return -EINVAL; out: pr_debug("governor: change or update limits\n"); return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } /** * cpufreq_update_policy - re-evaluate an existing cpufreq policy * @cpu: CPU which shall be re-evaluated * * Useful for policy notifiers which have different necessities * at different times. */ int cpufreq_update_policy(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); struct cpufreq_policy new_policy; int ret; if (!policy) return -ENODEV; down_write(&policy->rwsem); pr_debug("updating policy for CPU %u\n", cpu); memcpy(&new_policy, policy, sizeof(*policy)); new_policy.min = policy->user_policy.min; new_policy.max = policy->user_policy.max; new_policy.policy = policy->user_policy.policy; new_policy.governor = policy->user_policy.governor; /* * BIOS might change freq behind our back * -> ask driver for current freq and notify governors about a change */ if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { new_policy.cur = cpufreq_driver->get(cpu); if (WARN_ON(!new_policy.cur)) { ret = -EIO; goto unlock; } if (!policy->cur) { pr_debug("Driver did not initialize current freq\n"); policy->cur = new_policy.cur; } else { if (policy->cur != new_policy.cur && has_target()) cpufreq_out_of_sync(policy, new_policy.cur); } } ret = cpufreq_set_policy(policy, &new_policy); unlock: up_write(&policy->rwsem); cpufreq_cpu_put(policy); return ret; } EXPORT_SYMBOL(cpufreq_update_policy); static int cpufreq_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; struct device *dev; dev = get_cpu_device(cpu); if (dev) { switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: cpufreq_add_dev(dev, NULL); break; case CPU_DOWN_PREPARE: __cpufreq_remove_dev_prepare(dev, NULL); break; case CPU_POST_DEAD: __cpufreq_remove_dev_finish(dev, NULL); break; case CPU_DOWN_FAILED: cpufreq_add_dev(dev, NULL); break; } } return NOTIFY_OK; } static struct notifier_block __refdata cpufreq_cpu_notifier = { .notifier_call = cpufreq_cpu_callback, }; /********************************************************************* * BOOST * *********************************************************************/ static int cpufreq_boost_set_sw(int state) { struct cpufreq_frequency_table *freq_table; struct cpufreq_policy *policy; int ret = -EINVAL; for_each_active_policy(policy) { freq_table = cpufreq_frequency_get_table(policy->cpu); if (freq_table) { ret = cpufreq_frequency_table_cpuinfo(policy, freq_table); if (ret) { pr_err("%s: Policy frequency update failed\n", __func__); break; } policy->user_policy.max = policy->max; __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } } return ret; } int cpufreq_boost_trigger_state(int state) { unsigned long flags; int ret = 0; if (cpufreq_driver->boost_enabled == state) return 0; write_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver->boost_enabled = state; write_unlock_irqrestore(&cpufreq_driver_lock, flags); ret = cpufreq_driver->set_boost(state); if (ret) { write_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver->boost_enabled = !state; write_unlock_irqrestore(&cpufreq_driver_lock, flags); pr_err("%s: Cannot %s BOOST\n", __func__, state ? "enable" : "disable"); } return ret; } int cpufreq_boost_supported(void) { if (likely(cpufreq_driver)) return cpufreq_driver->boost_supported; return 0; } EXPORT_SYMBOL_GPL(cpufreq_boost_supported); int cpufreq_boost_enabled(void) { return cpufreq_driver->boost_enabled; } EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); /********************************************************************* * REGISTER / UNREGISTER CPUFREQ DRIVER * *********************************************************************/ /** * cpufreq_register_driver - register a CPU Frequency driver * @driver_data: A struct cpufreq_driver containing the values# * submitted by the CPU Frequency driver. * * Registers a CPU Frequency driver to this core code. This code * returns zero on success, -EBUSY when another driver got here first * (and isn't unregistered in the meantime). * */ int cpufreq_register_driver(struct cpufreq_driver *driver_data) { unsigned long flags; int ret; if (cpufreq_disabled()) return -ENODEV; if (!driver_data || !driver_data->verify || !driver_data->init || !(driver_data->setpolicy || driver_data->target_index || driver_data->target) || (driver_data->setpolicy && (driver_data->target_index || driver_data->target)) || (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) return -EINVAL; pr_debug("trying to register driver %s\n", driver_data->name); write_lock_irqsave(&cpufreq_driver_lock, flags); if (cpufreq_driver) { write_unlock_irqrestore(&cpufreq_driver_lock, flags); return -EEXIST; } cpufreq_driver = driver_data; write_unlock_irqrestore(&cpufreq_driver_lock, flags); if (driver_data->setpolicy) driver_data->flags |= CPUFREQ_CONST_LOOPS; if (cpufreq_boost_supported()) { /* * Check if driver provides function to enable boost - * if not, use cpufreq_boost_set_sw as default */ if (!cpufreq_driver->set_boost) cpufreq_driver->set_boost = cpufreq_boost_set_sw; ret = cpufreq_sysfs_create_file(&boost.attr); if (ret) { pr_err("%s: cannot register global BOOST sysfs file\n", __func__); goto err_null_driver; } } ret = subsys_interface_register(&cpufreq_interface); if (ret) goto err_boost_unreg; if (!(cpufreq_driver->flags & CPUFREQ_STICKY) && list_empty(&cpufreq_policy_list)) { /* if all ->init() calls failed, unregister */ pr_debug("%s: No CPU initialized for driver %s\n", __func__, driver_data->name); goto err_if_unreg; } register_hotcpu_notifier(&cpufreq_cpu_notifier); pr_debug("driver %s up and running\n", driver_data->name); return 0; err_if_unreg: subsys_interface_unregister(&cpufreq_interface); err_boost_unreg: if (cpufreq_boost_supported()) cpufreq_sysfs_remove_file(&boost.attr); err_null_driver: write_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; write_unlock_irqrestore(&cpufreq_driver_lock, flags); return ret; } EXPORT_SYMBOL_GPL(cpufreq_register_driver); /** * cpufreq_unregister_driver - unregister the current CPUFreq driver * * Unregister the current CPUFreq driver. Only call this if you have * the right to do so, i.e. if you have succeeded in initialising before! * Returns zero if successful, and -EINVAL if the cpufreq_driver is * currently not initialised. */ int cpufreq_unregister_driver(struct cpufreq_driver *driver) { unsigned long flags; if (!cpufreq_driver || (driver != cpufreq_driver)) return -EINVAL; pr_debug("unregistering driver %s\n", driver->name); subsys_interface_unregister(&cpufreq_interface); if (cpufreq_boost_supported()) cpufreq_sysfs_remove_file(&boost.attr); unregister_hotcpu_notifier(&cpufreq_cpu_notifier); down_write(&cpufreq_rwsem); write_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; write_unlock_irqrestore(&cpufreq_driver_lock, flags); up_write(&cpufreq_rwsem); return 0; } EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); /* * Stop cpufreq at shutdown to make sure it isn't holding any locks * or mutexes when secondary CPUs are halted. */ static struct syscore_ops cpufreq_syscore_ops = { .shutdown = cpufreq_suspend, }; static int __init cpufreq_core_init(void) { if (cpufreq_disabled()) return -ENODEV; cpufreq_global_kobject = kobject_create(); BUG_ON(!cpufreq_global_kobject); register_syscore_ops(&cpufreq_syscore_ops); return 0; } core_initcall(cpufreq_core_init);