/* * linux/drivers/cpufreq/cpufreq.c * * Copyright (C) 2001 Russell King * (C) 2002 - 2003 Dominik Brodowski * * 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. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** * The "cpufreq driver" - the arch- or hardware-dependent low * level driver of CPUFreq support, and its spinlock. This lock * also protects the cpufreq_cpu_data array. */ static struct cpufreq_driver *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); #ifdef CONFIG_HOTPLUG_CPU /* This one keeps track of the previously set governor of a removed CPU */ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); #endif static DEFINE_SPINLOCK(cpufreq_driver_lock); /* * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure * all cpufreq/hotplug/workqueue/etc related lock issues. * * The rules for this semaphore: * - Any routine that wants to read from the policy structure will * do a down_read on this semaphore. * - Any routine that will write to the policy structure and/or may take away * the policy altogether (eg. CPU hotplug), will hold this lock in write * mode before doing so. * * Additional rules: * - All holders of the lock should check to make sure that the CPU they * are concerned with are online after they get the lock. * - Governor routines that can be called in cpufreq hotplug path should not * take this sem as top level hotplug notifier handler takes this. * - Lock should not be held across * __cpufreq_governor(data, CPUFREQ_GOV_STOP); */ static DEFINE_PER_CPU(int, cpufreq_policy_cpu); static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem); #define lock_policy_rwsem(mode, cpu) \ static int lock_policy_rwsem_##mode \ (int cpu) \ { \ int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \ BUG_ON(policy_cpu == -1); \ down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ if (unlikely(!cpu_online(cpu))) { \ up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ return -1; \ } \ \ return 0; \ } lock_policy_rwsem(read, cpu); lock_policy_rwsem(write, cpu); static void unlock_policy_rwsem_read(int cpu) { int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); BUG_ON(policy_cpu == -1); up_read(&per_cpu(cpu_policy_rwsem, policy_cpu)); } static void unlock_policy_rwsem_write(int cpu) { int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); BUG_ON(policy_cpu == -1); up_write(&per_cpu(cpu_policy_rwsem, policy_cpu)); } /* internal prototypes */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); static unsigned int __cpufreq_get(unsigned int cpu); static void handle_update(struct work_struct *work); /** * Two notifier lists: the "policy" list is involved in the * validation process for a new CPU frequency policy; the * "transition" list for kernel code that needs to handle * changes to devices when the CPU clock speed changes. * The mutex locks both lists. */ static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); static struct srcu_notifier_head cpufreq_transition_notifier_list; static bool init_cpufreq_transition_notifier_list_called; static int __init init_cpufreq_transition_notifier_list(void) { srcu_init_notifier_head(&cpufreq_transition_notifier_list); init_cpufreq_transition_notifier_list_called = true; return 0; } pure_initcall(init_cpufreq_transition_notifier_list); static int off __read_mostly; int cpufreq_disabled(void) { return off; } void disable_cpufreq(void) { off = 1; } static LIST_HEAD(cpufreq_governor_list); static DEFINE_MUTEX(cpufreq_governor_mutex); static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) { struct cpufreq_policy *data; unsigned long flags; if (cpu >= nr_cpu_ids) goto err_out; /* get the cpufreq driver */ spin_lock_irqsave(&cpufreq_driver_lock, flags); if (!cpufreq_driver) goto err_out_unlock; if (!try_module_get(cpufreq_driver->owner)) goto err_out_unlock; /* get the CPU */ data = per_cpu(cpufreq_cpu_data, cpu); if (!data) goto err_out_put_module; if (!sysfs && !kobject_get(&data->kobj)) goto err_out_put_module; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); return data; err_out_put_module: module_put(cpufreq_driver->owner); err_out_unlock: spin_unlock_irqrestore(&cpufreq_driver_lock, flags); err_out: return NULL; } struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) { return __cpufreq_cpu_get(cpu, false); } EXPORT_SYMBOL_GPL(cpufreq_cpu_get); static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu) { return __cpufreq_cpu_get(cpu, true); } static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs) { if (!sysfs) kobject_put(&data->kobj); module_put(cpufreq_driver->owner); } void cpufreq_cpu_put(struct cpufreq_policy *data) { __cpufreq_cpu_put(data, false); } EXPORT_SYMBOL_GPL(cpufreq_cpu_put); static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data) { __cpufreq_cpu_put(data, true); } /********************************************************************* * EXTERNALLY AFFECTING FREQUENCY CHANGES * *********************************************************************/ /** * adjust_jiffies - adjust the system "loops_per_jiffy" * * This function alters the system "loops_per_jiffy" for the clock * speed change. Note that loops_per_jiffy cannot be updated on SMP * systems as each CPU might be scaled differently. So, use the arch * per-CPU loops_per_jiffy value wherever possible. */ #ifndef CONFIG_SMP static unsigned long l_p_j_ref; static unsigned int l_p_j_ref_freq; static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { if (ci->flags & CPUFREQ_CONST_LOOPS) return; if (!l_p_j_ref_freq) { l_p_j_ref = loops_per_jiffy; l_p_j_ref_freq = ci->old; pr_debug("saving %lu as reference value for loops_per_jiffy; " "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq); } if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) || (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) { loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new); pr_debug("scaling loops_per_jiffy to %lu " "for frequency %u kHz\n", loops_per_jiffy, ci->new); } } #else static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; } #endif /** * cpufreq_notify_transition - call notifier chain and adjust_jiffies * on frequency transition. * * This function calls the transition notifiers and the "adjust_jiffies" * function. It is called twice on all CPU frequency changes that have * external effects. */ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) { struct cpufreq_policy *policy; BUG_ON(irqs_disabled()); freqs->flags = cpufreq_driver->flags; pr_debug("notification %u of frequency transition to %u kHz\n", state, freqs->new); policy = per_cpu(cpufreq_cpu_data, freqs->cpu); switch (state) { case CPUFREQ_PRECHANGE: /* detect if the driver reported a value as "old frequency" * which is not equal to what the cpufreq core thinks is * "old frequency". */ if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { if ((policy) && (policy->cpu == freqs->cpu) && (policy->cur) && (policy->cur != freqs->old)) { pr_debug("Warning: CPU frequency is" " %u, cpufreq assumed %u kHz.\n", freqs->old, policy->cur); freqs->old = policy->cur; } } srcu_notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs); adjust_jiffies(CPUFREQ_PRECHANGE, freqs); break; case CPUFREQ_POSTCHANGE: adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new, (unsigned long)freqs->cpu); trace_power_frequency(POWER_PSTATE, freqs->new, 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; } } EXPORT_SYMBOL_GPL(cpufreq_notify_transition); /********************************************************************* * SYSFS INTERFACE * *********************************************************************/ static struct cpufreq_governor *__find_governor(const char *str_governor) { struct cpufreq_governor *t; list_for_each_entry(t, &cpufreq_governor_list, governor_list) if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN)) return t; return NULL; } /** * cpufreq_parse_governor - parse a governor string */ static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, struct cpufreq_governor **governor) { int err = -EINVAL; if (!cpufreq_driver) goto out; if (cpufreq_driver->setpolicy) { if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { *policy = CPUFREQ_POLICY_PERFORMANCE; err = 0; } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) { *policy = CPUFREQ_POLICY_POWERSAVE; err = 0; } } else if (cpufreq_driver->target) { struct cpufreq_governor *t; mutex_lock(&cpufreq_governor_mutex); t = __find_governor(str_governor); if (t == NULL) { int ret; mutex_unlock(&cpufreq_governor_mutex); ret = request_module("cpufreq_%s", str_governor); mutex_lock(&cpufreq_governor_mutex); if (ret == 0) t = __find_governor(str_governor); } if (t != NULL) { *governor = t; err = 0; } mutex_unlock(&cpufreq_governor_mutex); } out: return err; } /** * cpufreq_per_cpu_attr_read() / show_##file_name() - * print out cpufreq information * * Write out information from cpufreq_driver->policy[cpu]; object must be * "unsigned int". */ #define show_one(file_name, object) \ static ssize_t show_##file_name \ (struct cpufreq_policy *policy, char *buf) \ { \ return sprintf(buf, "%u\n", policy->object); \ } show_one(cpuinfo_min_freq, cpuinfo.min_freq); show_one(cpuinfo_max_freq, cpuinfo.max_freq); show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); show_one(scaling_cur_freq, cur); static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy); /** * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access */ #define store_one(file_name, object) \ static ssize_t store_##file_name \ (struct cpufreq_policy *policy, const char *buf, size_t count) \ { \ unsigned int ret = -EINVAL; \ struct cpufreq_policy new_policy; \ \ ret = cpufreq_get_policy(&new_policy, policy->cpu); \ if (ret) \ return -EINVAL; \ \ ret = sscanf(buf, "%u", &new_policy.object); \ if (ret != 1) \ return -EINVAL; \ \ ret = __cpufreq_set_policy(policy, &new_policy); \ policy->user_policy.object = policy->object; \ \ return ret ? ret : count; \ } store_one(scaling_min_freq, min); store_one(scaling_max_freq, max); /** * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware */ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, char *buf) { unsigned int cur_freq = __cpufreq_get(policy->cpu); if (!cur_freq) return sprintf(buf, ""); return sprintf(buf, "%u\n", cur_freq); } /** * show_scaling_governor - show the current policy for the specified CPU */ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) { if (policy->policy == CPUFREQ_POLICY_POWERSAVE) return sprintf(buf, "powersave\n"); else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) return sprintf(buf, "performance\n"); else if (policy->governor) return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", policy->governor->name); return -EINVAL; } /** * store_scaling_governor - store policy for the specified CPU */ static ssize_t store_scaling_governor(struct cpufreq_policy *policy, const char *buf, size_t count) { unsigned int ret = -EINVAL; char str_governor[16]; struct cpufreq_policy new_policy; ret = cpufreq_get_policy(&new_policy, policy->cpu); if (ret) return ret; ret = sscanf(buf, "%15s", str_governor); if (ret != 1) return -EINVAL; if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor)) return -EINVAL; /* Do not use cpufreq_set_policy here or the user_policy.max will be wrongly overridden */ ret = __cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; if (ret) return ret; else return count; } /** * show_scaling_driver - show the cpufreq driver currently loaded */ static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) { return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); } /** * show_scaling_available_governors - show the available CPUfreq governors */ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, char *buf) { ssize_t i = 0; struct cpufreq_governor *t; if (!cpufreq_driver->target) { i += sprintf(buf, "performance powersave"); goto out; } list_for_each_entry(t, &cpufreq_governor_list, governor_list) { if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2))) goto out; i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); } out: i += sprintf(&buf[i], "\n"); return i; } static ssize_t show_cpus(const struct cpumask *mask, char *buf) { ssize_t i = 0; unsigned int cpu; for_each_cpu(cpu, mask) { if (i) i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); if (i >= (PAGE_SIZE - 5)) break; } i += sprintf(&buf[i], "\n"); return i; } /** * show_related_cpus - show the CPUs affected by each transition even if * hw coordination is in use */ static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) { if (cpumask_empty(policy->related_cpus)) return show_cpus(policy->cpus, buf); return show_cpus(policy->related_cpus, buf); } /** * show_affected_cpus - show the CPUs affected by each transition */ static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) { return show_cpus(policy->cpus, buf); } static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, const char *buf, size_t count) { unsigned int freq = 0; unsigned int ret; if (!policy->governor || !policy->governor->store_setspeed) return -EINVAL; ret = sscanf(buf, "%u", &freq); if (ret != 1) return -EINVAL; policy->governor->store_setspeed(policy, freq); return count; } static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) { if (!policy->governor || !policy->governor->show_setspeed) return sprintf(buf, "\n"); return policy->governor->show_setspeed(policy, buf); } /** * show_bios_limit - show the current cpufreq HW/BIOS limitation */ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) { unsigned int limit; int ret; if (cpufreq_driver->bios_limit) { ret = cpufreq_driver->bios_limit(policy->cpu, &limit); if (!ret) return sprintf(buf, "%u\n", limit); } return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); } cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); cpufreq_freq_attr_ro(cpuinfo_min_freq); cpufreq_freq_attr_ro(cpuinfo_max_freq); cpufreq_freq_attr_ro(cpuinfo_transition_latency); cpufreq_freq_attr_ro(scaling_available_governors); cpufreq_freq_attr_ro(scaling_driver); cpufreq_freq_attr_ro(scaling_cur_freq); cpufreq_freq_attr_ro(bios_limit); cpufreq_freq_attr_ro(related_cpus); cpufreq_freq_attr_ro(affected_cpus); cpufreq_freq_attr_rw(scaling_min_freq); cpufreq_freq_attr_rw(scaling_max_freq); cpufreq_freq_attr_rw(scaling_governor); cpufreq_freq_attr_rw(scaling_setspeed); static struct attribute *default_attrs[] = { &cpuinfo_min_freq.attr, &cpuinfo_max_freq.attr, &cpuinfo_transition_latency.attr, &scaling_min_freq.attr, &scaling_max_freq.attr, &affected_cpus.attr, &related_cpus.attr, &scaling_governor.attr, &scaling_driver.attr, &scaling_available_governors.attr, &scaling_setspeed.attr, NULL }; struct kobject *cpufreq_global_kobject; EXPORT_SYMBOL(cpufreq_global_kobject); #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) #define to_attr(a) container_of(a, struct freq_attr, attr) static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; policy = cpufreq_cpu_get_sysfs(policy->cpu); if (!policy) goto no_policy; if (lock_policy_rwsem_read(policy->cpu) < 0) goto fail; if (fattr->show) ret = fattr->show(policy, buf); else ret = -EIO; unlock_policy_rwsem_read(policy->cpu); fail: cpufreq_cpu_put_sysfs(policy); no_policy: return ret; } static ssize_t store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; policy = cpufreq_cpu_get_sysfs(policy->cpu); if (!policy) goto no_policy; if (lock_policy_rwsem_write(policy->cpu) < 0) goto fail; if (fattr->store) ret = fattr->store(policy, buf, count); else ret = -EIO; unlock_policy_rwsem_write(policy->cpu); fail: cpufreq_cpu_put_sysfs(policy); no_policy: return ret; } static void cpufreq_sysfs_release(struct kobject *kobj) { struct cpufreq_policy *policy = to_policy(kobj); pr_debug("last reference is dropped\n"); complete(&policy->kobj_unregister); } static const struct sysfs_ops sysfs_ops = { .show = show, .store = store, }; static struct kobj_type ktype_cpufreq = { .sysfs_ops = &sysfs_ops, .default_attrs = default_attrs, .release = cpufreq_sysfs_release, }; /* * Returns: * Negative: Failure * 0: Success * Positive: When we have a managed CPU and the sysfs got symlinked */ static int cpufreq_add_dev_policy(unsigned int cpu, struct cpufreq_policy *policy, struct device *dev) { int ret = 0; #ifdef CONFIG_SMP unsigned long flags; unsigned int j; #ifdef CONFIG_HOTPLUG_CPU struct cpufreq_governor *gov; gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu)); if (gov) { policy->governor = gov; pr_debug("Restoring governor %s for cpu %d\n", policy->governor->name, cpu); } #endif for_each_cpu(j, policy->cpus) { struct cpufreq_policy *managed_policy; if (cpu == j) continue; /* Check for existing affected CPUs. * They may not be aware of it due to CPU Hotplug. * cpufreq_cpu_put is called when the device is removed * in __cpufreq_remove_dev() */ managed_policy = cpufreq_cpu_get(j); if (unlikely(managed_policy)) { /* Set proper policy_cpu */ unlock_policy_rwsem_write(cpu); per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu; if (lock_policy_rwsem_write(cpu) < 0) { /* Should not go through policy unlock path */ if (cpufreq_driver->exit) cpufreq_driver->exit(policy); cpufreq_cpu_put(managed_policy); return -EBUSY; } spin_lock_irqsave(&cpufreq_driver_lock, flags); cpumask_copy(managed_policy->cpus, policy->cpus); per_cpu(cpufreq_cpu_data, cpu) = managed_policy; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); pr_debug("CPU already managed, adding link\n"); ret = sysfs_create_link(&dev->kobj, &managed_policy->kobj, "cpufreq"); if (ret) cpufreq_cpu_put(managed_policy); /* * Success. We only needed to be added to the mask. * Call driver->exit() because only the cpu parent of * the kobj needed to call init(). */ if (cpufreq_driver->exit) cpufreq_driver->exit(policy); if (!ret) return 1; else return ret; } } #endif return ret; } /* symlink affected CPUs */ static int cpufreq_add_dev_symlink(unsigned int cpu, struct cpufreq_policy *policy) { unsigned int j; int ret = 0; for_each_cpu(j, policy->cpus) { struct cpufreq_policy *managed_policy; struct device *cpu_dev; if (j == cpu) continue; if (!cpu_online(j)) continue; pr_debug("CPU %u already managed, adding link\n", j); managed_policy = cpufreq_cpu_get(cpu); cpu_dev = get_cpu_device(j); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); if (ret) { cpufreq_cpu_put(managed_policy); return ret; } } return ret; } static int cpufreq_add_dev_interface(unsigned int cpu, struct cpufreq_policy *policy, struct device *dev) { struct cpufreq_policy new_policy; struct freq_attr **drv_attr; unsigned long flags; int ret = 0; unsigned int j; /* prepare interface data */ ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj, "cpufreq"); if (ret) return ret; /* set up files for this cpu device */ drv_attr = cpufreq_driver->attr; while ((drv_attr) && (*drv_attr)) { ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); if (ret) goto err_out_kobj_put; drv_attr++; } if (cpufreq_driver->get) { ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); if (ret) goto err_out_kobj_put; } if (cpufreq_driver->target) { ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); if (ret) goto err_out_kobj_put; } if (cpufreq_driver->bios_limit) { ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); if (ret) goto err_out_kobj_put; } spin_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) { if (!cpu_online(j)) continue; per_cpu(cpufreq_cpu_data, j) = policy; per_cpu(cpufreq_policy_cpu, j) = policy->cpu; } spin_unlock_irqrestore(&cpufreq_driver_lock, flags); ret = cpufreq_add_dev_symlink(cpu, policy); if (ret) goto err_out_kobj_put; memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); /* assure that the starting sequence is run in __cpufreq_set_policy */ policy->governor = NULL; /* set default policy */ ret = __cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; if (ret) { pr_debug("setting policy failed\n"); if (cpufreq_driver->exit) cpufreq_driver->exit(policy); } return ret; err_out_kobj_put: kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); return ret; } /** * 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 cpu = dev->id; int ret = 0, found = 0; struct cpufreq_policy *policy; unsigned long flags; unsigned int j; #ifdef CONFIG_HOTPLUG_CPU int sibling; #endif if (cpu_is_offline(cpu)) return 0; pr_debug("adding CPU %u\n", cpu); #ifdef CONFIG_SMP /* check whether a different CPU already registered this * CPU because it is in the same boat. */ policy = cpufreq_cpu_get(cpu); if (unlikely(policy)) { cpufreq_cpu_put(policy); return 0; } #endif if (!try_module_get(cpufreq_driver->owner)) { ret = -EINVAL; goto module_out; } ret = -ENOMEM; policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); if (!policy) goto nomem_out; if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) goto err_free_policy; if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) goto err_free_cpumask; policy->cpu = cpu; cpumask_copy(policy->cpus, cpumask_of(cpu)); /* Initially set CPU itself as the policy_cpu */ per_cpu(cpufreq_policy_cpu, cpu) = cpu; ret = (lock_policy_rwsem_write(cpu) < 0); WARN_ON(ret); init_completion(&policy->kobj_unregister); INIT_WORK(&policy->update, handle_update); /* Set governor before ->init, so that driver could check it */ #ifdef CONFIG_HOTPLUG_CPU for_each_online_cpu(sibling) { struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); if (cp && cp->governor && (cpumask_test_cpu(cpu, cp->related_cpus))) { policy->governor = cp->governor; found = 1; break; } } #endif if (!found) policy->governor = CPUFREQ_DEFAULT_GOVERNOR; /* 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_unlock_policy; } policy->user_policy.min = policy->min; policy->user_policy.max = policy->max; blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_START, policy); ret = cpufreq_add_dev_policy(cpu, policy, dev); if (ret) { if (ret > 0) /* This is a managed cpu, symlink created, exit with 0 */ ret = 0; goto err_unlock_policy; } ret = cpufreq_add_dev_interface(cpu, policy, dev); if (ret) goto err_out_unregister; unlock_policy_rwsem_write(cpu); kobject_uevent(&policy->kobj, KOBJ_ADD); module_put(cpufreq_driver->owner); pr_debug("initialization complete\n"); return 0; err_out_unregister: spin_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = NULL; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); err_unlock_policy: unlock_policy_rwsem_write(cpu); free_cpumask_var(policy->related_cpus); err_free_cpumask: free_cpumask_var(policy->cpus); err_free_policy: kfree(policy); nomem_out: module_put(cpufreq_driver->owner); module_out: return ret; } /** * __cpufreq_remove_dev - remove a CPU device * * Removes the cpufreq interface for a CPU device. * Caller should already have policy_rwsem in write mode for this CPU. * This routine frees the rwsem before returning. */ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; unsigned long flags; struct cpufreq_policy *data; struct kobject *kobj; struct completion *cmp; #ifdef CONFIG_SMP struct device *cpu_dev; unsigned int j; #endif pr_debug("unregistering CPU %u\n", cpu); spin_lock_irqsave(&cpufreq_driver_lock, flags); data = per_cpu(cpufreq_cpu_data, cpu); if (!data) { spin_unlock_irqrestore(&cpufreq_driver_lock, flags); unlock_policy_rwsem_write(cpu); return -EINVAL; } per_cpu(cpufreq_cpu_data, cpu) = NULL; #ifdef CONFIG_SMP /* if this isn't the CPU which is the parent of the kobj, we * only need to unlink, put and exit */ if (unlikely(cpu != data->cpu)) { pr_debug("removing link\n"); cpumask_clear_cpu(cpu, data->cpus); spin_unlock_irqrestore(&cpufreq_driver_lock, flags); kobj = &dev->kobj; cpufreq_cpu_put(data); unlock_policy_rwsem_write(cpu); sysfs_remove_link(kobj, "cpufreq"); return 0; } #endif #ifdef CONFIG_SMP #ifdef CONFIG_HOTPLUG_CPU strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name, CPUFREQ_NAME_LEN); #endif /* if we have other CPUs still registered, we need to unlink them, * or else wait_for_completion below will lock up. Clean the * per_cpu(cpufreq_cpu_data) while holding the lock, and remove * the sysfs links afterwards. */ if (unlikely(cpumask_weight(data->cpus) > 1)) { for_each_cpu(j, data->cpus) { if (j == cpu) continue; per_cpu(cpufreq_cpu_data, j) = NULL; } } spin_unlock_irqrestore(&cpufreq_driver_lock, flags); if (unlikely(cpumask_weight(data->cpus) > 1)) { for_each_cpu(j, data->cpus) { if (j == cpu) continue; pr_debug("removing link for cpu %u\n", j); #ifdef CONFIG_HOTPLUG_CPU strncpy(per_cpu(cpufreq_cpu_governor, j), data->governor->name, CPUFREQ_NAME_LEN); #endif cpu_dev = get_cpu_device(j); kobj = &cpu_dev->kobj; unlock_policy_rwsem_write(cpu); sysfs_remove_link(kobj, "cpufreq"); lock_policy_rwsem_write(cpu); cpufreq_cpu_put(data); } } #else spin_unlock_irqrestore(&cpufreq_driver_lock, flags); #endif if (cpufreq_driver->target) __cpufreq_governor(data, CPUFREQ_GOV_STOP); kobj = &data->kobj; cmp = &data->kobj_unregister; unlock_policy_rwsem_write(cpu); kobject_put(kobj); /* we need to make sure that the underlying kobj is actually * not referenced anymore by anybody before we proceed with * unloading. */ pr_debug("waiting for dropping of refcount\n"); wait_for_completion(cmp); pr_debug("wait complete\n"); lock_policy_rwsem_write(cpu); if (cpufreq_driver->exit) cpufreq_driver->exit(data); unlock_policy_rwsem_write(cpu); #ifdef CONFIG_HOTPLUG_CPU /* when the CPU which is the parent of the kobj is hotplugged * offline, check for siblings, and create cpufreq sysfs interface * and symlinks */ if (unlikely(cpumask_weight(data->cpus) > 1)) { /* first sibling now owns the new sysfs dir */ cpumask_clear_cpu(cpu, data->cpus); cpufreq_add_dev(get_cpu_device(cpumask_first(data->cpus)), NULL); /* finally remove our own symlink */ lock_policy_rwsem_write(cpu); __cpufreq_remove_dev(dev, sif); } #endif free_cpumask_var(data->related_cpus); free_cpumask_var(data->cpus); kfree(data); return 0; } static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; int retval; if (cpu_is_offline(cpu)) return 0; if (unlikely(lock_policy_rwsem_write(cpu))) BUG(); retval = __cpufreq_remove_dev(dev, sif); return retval; } static void handle_update(struct work_struct *work) { struct cpufreq_policy *policy = container_of(work, struct cpufreq_policy, update); unsigned int cpu = policy->cpu; pr_debug("handle_update for cpu %u called\n", cpu); cpufreq_update_policy(cpu); } /** * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble. * @cpu: cpu number * @old_freq: CPU frequency the kernel thinks the CPU runs at * @new_freq: CPU frequency the CPU actually runs at * * We adjust to current frequency first, and need to clean up later. * So either call to cpufreq_update_policy() or schedule handle_update()). */ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq) { struct cpufreq_freqs freqs; pr_debug("Warning: CPU frequency out of sync: cpufreq and timing " "core thinks of %u, is %u kHz.\n", old_freq, new_freq); freqs.cpu = cpu; freqs.old = old_freq; freqs.new = new_freq; cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); } /** * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur * @cpu: CPU number * * This is the last known freq, without actually getting it from the driver. * Return value will be same as what is shown in scaling_cur_freq in sysfs. */ unsigned int cpufreq_quick_get(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); unsigned int ret_freq = 0; if (policy) { ret_freq = policy->cur; cpufreq_cpu_put(policy); } return ret_freq; } EXPORT_SYMBOL(cpufreq_quick_get); /** * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU * @cpu: CPU number * * Just return the max possible frequency for a given CPU. */ unsigned int cpufreq_quick_get_max(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); unsigned int ret_freq = 0; if (policy) { ret_freq = policy->max; cpufreq_cpu_put(policy); } return ret_freq; } EXPORT_SYMBOL(cpufreq_quick_get_max); static unsigned int __cpufreq_get(unsigned int cpu) { struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); unsigned int ret_freq = 0; if (!cpufreq_driver->get) return ret_freq; ret_freq = cpufreq_driver->get(cpu); if (ret_freq && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { /* verify no discrepancy between actual and saved value exists */ if (unlikely(ret_freq != policy->cur)) { cpufreq_out_of_sync(cpu, policy->cur, ret_freq); schedule_work(&policy->update); } } return ret_freq; } /** * cpufreq_get - get the current CPU frequency (in kHz) * @cpu: CPU number * * Get the CPU current (static) CPU frequency */ unsigned int cpufreq_get(unsigned int cpu) { unsigned int ret_freq = 0; struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); if (!policy) goto out; if (unlikely(lock_policy_rwsem_read(cpu))) goto out_policy; ret_freq = __cpufreq_get(cpu); unlock_policy_rwsem_read(cpu); out_policy: cpufreq_cpu_put(policy); out: return ret_freq; } EXPORT_SYMBOL(cpufreq_get); static struct subsys_interface cpufreq_interface = { .name = "cpufreq", .subsys = &cpu_subsys, .add_dev = cpufreq_add_dev, .remove_dev = cpufreq_remove_dev, }; /** * cpufreq_bp_suspend - Prepare the boot CPU for system suspend. * * This function is only executed for the boot processor. The other CPUs * have been put offline by means of CPU hotplug. */ static int cpufreq_bp_suspend(void) { int ret = 0; int cpu = smp_processor_id(); struct cpufreq_policy *cpu_policy; pr_debug("suspending cpu %u\n", cpu); /* If there's no policy for the boot CPU, we have nothing to do. */ cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return 0; if (cpufreq_driver->suspend) { ret = cpufreq_driver->suspend(cpu_policy); if (ret) printk(KERN_ERR "cpufreq: suspend failed in ->suspend " "step on CPU %u\n", cpu_policy->cpu); } cpufreq_cpu_put(cpu_policy); return ret; } /** * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU. * * 1.) resume CPUfreq hardware support (cpufreq_driver->resume()) * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are * restored. It will verify that the current freq is in sync with * what we believe it to be. This is a bit later than when it * should be, but nonethteless it's better than calling * cpufreq_driver->get() here which might re-enable interrupts... * * This function is only executed for the boot CPU. The other CPUs have not * been turned on yet. */ static void cpufreq_bp_resume(void) { int ret = 0; int cpu = smp_processor_id(); struct cpufreq_policy *cpu_policy; pr_debug("resuming cpu %u\n", cpu); /* If there's no policy for the boot CPU, we have nothing to do. */ cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return; if (cpufreq_driver->resume) { ret = cpufreq_driver->resume(cpu_policy); if (ret) { printk(KERN_ERR "cpufreq: resume failed in ->resume " "step on CPU %u\n", cpu_policy->cpu); goto fail; } } schedule_work(&cpu_policy->update); fail: cpufreq_cpu_put(cpu_policy); } static struct syscore_ops cpufreq_syscore_ops = { .suspend = cpufreq_bp_suspend, .resume = cpufreq_bp_resume, }; /********************************************************************* * 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; 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; switch (list) { case CPUFREQ_TRANSITION_NOTIFIER: ret = srcu_notifier_chain_unregister( &cpufreq_transition_notifier_list, nb); break; case CPUFREQ_POLICY_NOTIFIER: ret = blocking_notifier_chain_unregister( &cpufreq_policy_notifier_list, nb); break; default: ret = -EINVAL; } return ret; } EXPORT_SYMBOL(cpufreq_unregister_notifier); /********************************************************************* * GOVERNORS * *********************************************************************/ int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int retval = -EINVAL; if (cpufreq_disabled()) return -ENODEV; pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu, target_freq, relation); if (cpu_online(policy->cpu) && cpufreq_driver->target) retval = cpufreq_driver->target(policy, target_freq, relation); return retval; } EXPORT_SYMBOL_GPL(__cpufreq_driver_target); int cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int ret = -EINVAL; policy = cpufreq_cpu_get(policy->cpu); if (!policy) goto no_policy; if (unlikely(lock_policy_rwsem_write(policy->cpu))) goto fail; ret = __cpufreq_driver_target(policy, target_freq, relation); unlock_policy_rwsem_write(policy->cpu); fail: cpufreq_cpu_put(policy); no_policy: return ret; } EXPORT_SYMBOL_GPL(cpufreq_driver_target); int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu) { int ret = 0; policy = cpufreq_cpu_get(policy->cpu); if (!policy) return -EINVAL; if (cpu_online(cpu) && cpufreq_driver->getavg) ret = cpufreq_driver->getavg(policy, cpu); cpufreq_cpu_put(policy); return ret; } EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg); /* * when "event" is CPUFREQ_GOV_LIMITS */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event) { int ret; /* Only must be defined when default governor is known to have latency restrictions, like e.g. conservative or ondemand. That this is the case is already ensured in Kconfig */ #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE struct cpufreq_governor *gov = &cpufreq_gov_performance; #else struct cpufreq_governor *gov = NULL; #endif if (policy->governor->max_transition_latency && policy->cpuinfo.transition_latency > policy->governor->max_transition_latency) { if (!gov) return -EINVAL; else { printk(KERN_WARNING "%s governor failed, too long" " transition latency of HW, fallback" " to %s governor\n", policy->governor->name, gov->name); policy->governor = gov; } } if (!try_module_get(policy->governor->owner)) return -EINVAL; pr_debug("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event); ret = policy->governor->governor(policy, event); /* we keep one module reference alive for each CPU governed by this CPU */ if ((event != CPUFREQ_GOV_START) || ret) module_put(policy->governor->owner); if ((event == CPUFREQ_GOV_STOP) && !ret) module_put(policy->governor->owner); return ret; } int cpufreq_register_governor(struct cpufreq_governor *governor) { int err; if (!governor) return -EINVAL; if (cpufreq_disabled()) return -ENODEV; mutex_lock(&cpufreq_governor_mutex); err = -EBUSY; if (__find_governor(governor->name) == NULL) { err = 0; list_add(&governor->governor_list, &cpufreq_governor_list); } mutex_unlock(&cpufreq_governor_mutex); return err; } EXPORT_SYMBOL_GPL(cpufreq_register_governor); void cpufreq_unregister_governor(struct cpufreq_governor *governor) { #ifdef CONFIG_HOTPLUG_CPU int cpu; #endif if (!governor) return; if (cpufreq_disabled()) return; #ifdef CONFIG_HOTPLUG_CPU for_each_present_cpu(cpu) { if (cpu_online(cpu)) continue; if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name)) strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0"); } #endif mutex_lock(&cpufreq_governor_mutex); list_del(&governor->governor_list); mutex_unlock(&cpufreq_governor_mutex); return; } EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); /********************************************************************* * POLICY INTERFACE * *********************************************************************/ /** * cpufreq_get_policy - get the current cpufreq_policy * @policy: struct cpufreq_policy into which the current cpufreq_policy * is written * * Reads the current cpufreq policy. */ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) { struct cpufreq_policy *cpu_policy; if (!policy) return -EINVAL; cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return -EINVAL; memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); cpufreq_cpu_put(cpu_policy); return 0; } EXPORT_SYMBOL(cpufreq_get_policy); /* * data : current policy. * policy : policy to be set. */ static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy) { int ret = 0; pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu, policy->min, policy->max); memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo)); if (policy->min > data->max || policy->max < data->min) { ret = -EINVAL; goto error_out; } /* verify the cpu speed can be set within this limit */ ret = cpufreq_driver->verify(policy); if (ret) goto error_out; /* adjust if necessary - all reasons */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST, policy); /* adjust if necessary - hardware incompatibility*/ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE, policy); /* verify the cpu speed can be set within this limit, which might be different to the first one */ ret = cpufreq_driver->verify(policy); if (ret) goto error_out; /* notification of the new policy */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY, policy); data->min = policy->min; data->max = policy->max; pr_debug("new min and max freqs are %u - %u kHz\n", data->min, data->max); if (cpufreq_driver->setpolicy) { data->policy = policy->policy; pr_debug("setting range\n"); ret = cpufreq_driver->setpolicy(policy); } else { if (policy->governor != data->governor) { /* save old, working values */ struct cpufreq_governor *old_gov = data->governor; pr_debug("governor switch\n"); /* end old governor */ if (data->governor) __cpufreq_governor(data, CPUFREQ_GOV_STOP); /* start new governor */ data->governor = policy->governor; if (__cpufreq_governor(data, CPUFREQ_GOV_START)) { /* new governor failed, so re-start old one */ pr_debug("starting governor %s failed\n", data->governor->name); if (old_gov) { data->governor = old_gov; __cpufreq_governor(data, CPUFREQ_GOV_START); } ret = -EINVAL; goto error_out; } /* might be a policy change, too, so fall through */ } pr_debug("governor: change or update limits\n"); __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); } error_out: return ret; } /** * cpufreq_update_policy - re-evaluate an existing cpufreq policy * @cpu: CPU which shall be re-evaluated * * Useful for policy notifiers which have different necessities * at different times. */ int cpufreq_update_policy(unsigned int cpu) { struct cpufreq_policy *data = cpufreq_cpu_get(cpu); struct cpufreq_policy policy; int ret; if (!data) { ret = -ENODEV; goto no_policy; } if (unlikely(lock_policy_rwsem_write(cpu))) { ret = -EINVAL; goto fail; } pr_debug("updating policy for CPU %u\n", cpu); memcpy(&policy, data, sizeof(struct cpufreq_policy)); policy.min = data->user_policy.min; policy.max = data->user_policy.max; policy.policy = data->user_policy.policy; policy.governor = data->user_policy.governor; /* BIOS might change freq behind our back -> ask driver for current freq and notify governors about a change */ if (cpufreq_driver->get) { policy.cur = cpufreq_driver->get(cpu); if (!data->cur) { pr_debug("Driver did not initialize current freq"); data->cur = policy.cur; } else { if (data->cur != policy.cur) cpufreq_out_of_sync(cpu, data->cur, policy.cur); } } ret = __cpufreq_set_policy(data, &policy); unlock_policy_rwsem_write(cpu); fail: cpufreq_cpu_put(data); no_policy: return ret; } EXPORT_SYMBOL(cpufreq_update_policy); static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; struct device *dev; dev = get_cpu_device(cpu); if (dev) { switch (action) { case CPU_ONLINE: case CPU_ONLINE_FROZEN: cpufreq_add_dev(dev, NULL); break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: if (unlikely(lock_policy_rwsem_write(cpu))) BUG(); __cpufreq_remove_dev(dev, NULL); break; case CPU_DOWN_FAILED: case CPU_DOWN_FAILED_FROZEN: cpufreq_add_dev(dev, NULL); break; } } return NOTIFY_OK; } static struct notifier_block __refdata cpufreq_cpu_notifier = { .notifier_call = cpufreq_cpu_callback, }; /********************************************************************* * REGISTER / UNREGISTER CPUFREQ DRIVER * *********************************************************************/ /** * cpufreq_register_driver - register a CPU Frequency driver * @driver_data: A struct cpufreq_driver containing the values# * submitted by the CPU Frequency driver. * * Registers a CPU Frequency driver to this core code. This code * returns zero on success, -EBUSY when another driver got here first * (and isn't unregistered in the meantime). * */ int cpufreq_register_driver(struct cpufreq_driver *driver_data) { unsigned long flags; int ret; if (cpufreq_disabled()) return -ENODEV; if (!driver_data || !driver_data->verify || !driver_data->init || ((!driver_data->setpolicy) && (!driver_data->target))) return -EINVAL; pr_debug("trying to register driver %s\n", driver_data->name); if (driver_data->setpolicy) driver_data->flags |= CPUFREQ_CONST_LOOPS; spin_lock_irqsave(&cpufreq_driver_lock, flags); if (cpufreq_driver) { spin_unlock_irqrestore(&cpufreq_driver_lock, flags); return -EBUSY; } cpufreq_driver = driver_data; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); ret = subsys_interface_register(&cpufreq_interface); if (ret) goto err_null_driver; if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { int i; ret = -ENODEV; /* check for at least one working CPU */ for (i = 0; i < nr_cpu_ids; i++) if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { ret = 0; break; } /* if all ->init() calls failed, unregister */ if (ret) { pr_debug("no CPU initialized for driver %s\n", driver_data->name); goto err_if_unreg; } } register_hotcpu_notifier(&cpufreq_cpu_notifier); pr_debug("driver %s up and running\n", driver_data->name); return 0; err_if_unreg: subsys_interface_unregister(&cpufreq_interface); err_null_driver: spin_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); return ret; } EXPORT_SYMBOL_GPL(cpufreq_register_driver); /** * cpufreq_unregister_driver - unregister the current CPUFreq driver * * Unregister the current CPUFreq driver. Only call this if you have * the right to do so, i.e. if you have succeeded in initialising before! * Returns zero if successful, and -EINVAL if the cpufreq_driver is * currently not initialised. */ int cpufreq_unregister_driver(struct cpufreq_driver *driver) { unsigned long flags; if (!cpufreq_driver || (driver != cpufreq_driver)) return -EINVAL; pr_debug("unregistering driver %s\n", driver->name); subsys_interface_unregister(&cpufreq_interface); unregister_hotcpu_notifier(&cpufreq_cpu_notifier); spin_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); return 0; } EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); static int __init cpufreq_core_init(void) { int cpu; if (cpufreq_disabled()) return -ENODEV; for_each_possible_cpu(cpu) { per_cpu(cpufreq_policy_cpu, cpu) = -1; init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); } cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj); BUG_ON(!cpufreq_global_kobject); register_syscore_ops(&cpufreq_syscore_ops); return 0; } core_initcall(cpufreq_core_init);