/* * linux/drivers/cpufreq/cpufreq.c * * Copyright (C) 2001 Russell King * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> * * Oct 2005 - Ashok Raj <ashok.raj@intel.com> * Added handling for CPU hotplug * Feb 2006 - Jacob Shin <jacob.shin@amd.com> * Fix handling for CPU hotplug -- affected CPUs * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/notifier.h> #include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/spinlock.h> #include <linux/device.h> #include <linux/slab.h> #include <linux/cpu.h> #include <linux/completion.h> #include <linux/mutex.h> #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg) /** * 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 struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS]; static DEFINE_SPINLOCK(cpufreq_driver_lock); /* internal prototypes */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); static void handle_update(void *data); /** * 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 int __init init_cpufreq_transition_notifier_list(void) { srcu_init_notifier_head(&cpufreq_transition_notifier_list); return 0; } core_initcall(init_cpufreq_transition_notifier_list); static LIST_HEAD(cpufreq_governor_list); static DEFINE_MUTEX (cpufreq_governor_mutex); struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) { struct cpufreq_policy *data; unsigned long flags; if (cpu >= NR_CPUS) 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 = cpufreq_cpu_data[cpu]; if (!data) goto err_out_put_module; if (!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; } EXPORT_SYMBOL_GPL(cpufreq_cpu_get); void cpufreq_cpu_put(struct cpufreq_policy *data) { kobject_put(&data->kobj); module_put(cpufreq_driver->owner); } EXPORT_SYMBOL_GPL(cpufreq_cpu_put); /********************************************************************* * UNIFIED DEBUG HELPERS * *********************************************************************/ #ifdef CONFIG_CPU_FREQ_DEBUG /* what part(s) of the CPUfreq subsystem are debugged? */ static unsigned int debug; /* is the debug output ratelimit'ed using printk_ratelimit? User can * set or modify this value. */ static unsigned int debug_ratelimit = 1; /* is the printk_ratelimit'ing enabled? It's enabled after a successful * loading of a cpufreq driver, temporarily disabled when a new policy * is set, and disabled upon cpufreq driver removal */ static unsigned int disable_ratelimit = 1; static DEFINE_SPINLOCK(disable_ratelimit_lock); static void cpufreq_debug_enable_ratelimit(void) { unsigned long flags; spin_lock_irqsave(&disable_ratelimit_lock, flags); if (disable_ratelimit) disable_ratelimit--; spin_unlock_irqrestore(&disable_ratelimit_lock, flags); } static void cpufreq_debug_disable_ratelimit(void) { unsigned long flags; spin_lock_irqsave(&disable_ratelimit_lock, flags); disable_ratelimit++; spin_unlock_irqrestore(&disable_ratelimit_lock, flags); } void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...) { char s[256]; va_list args; unsigned int len; unsigned long flags; WARN_ON(!prefix); if (type & debug) { spin_lock_irqsave(&disable_ratelimit_lock, flags); if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) { spin_unlock_irqrestore(&disable_ratelimit_lock, flags); return; } spin_unlock_irqrestore(&disable_ratelimit_lock, flags); len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix); va_start(args, fmt); len += vsnprintf(&s[len], (256 - len), fmt, args); va_end(args); printk(s); WARN_ON(len < 5); } } EXPORT_SYMBOL(cpufreq_debug_printk); module_param(debug, uint, 0644); MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors."); module_param(debug_ratelimit, uint, 0644); MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting."); #else /* !CONFIG_CPU_FREQ_DEBUG */ static inline void cpufreq_debug_enable_ratelimit(void) { return; } static inline void cpufreq_debug_disable_ratelimit(void) { return; } #endif /* CONFIG_CPU_FREQ_DEBUG */ /********************************************************************* * 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; dprintk("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_PRECHANGE && ci->old < ci->new) || (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); dprintk("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; dprintk("notification %u of frequency transition to %u kHz\n", state, freqs->new); policy = 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)) { dprintk("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); 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) { char *name = kasprintf(GFP_KERNEL, "cpufreq_%s", str_governor); if (name) { int ret; mutex_unlock(&cpufreq_governor_mutex); ret = request_module(name); mutex_lock(&cpufreq_governor_mutex); if (ret == 0) t = __find_governor(str_governor); } kfree(name); } if (t != NULL) { *governor = t; err = 0; } mutex_unlock(&cpufreq_governor_mutex); } out: return err; } /* drivers/base/cpu.c */ extern struct sysdev_class cpu_sysdev_class; /** * 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(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; \ \ lock_cpu_hotplug(); \ mutex_lock(&policy->lock); \ ret = __cpufreq_set_policy(policy, &new_policy); \ policy->user_policy.object = policy->object; \ mutex_unlock(&policy->lock); \ unlock_cpu_hotplug(); \ \ return ret ? ret : count; \ } store_one(scaling_min_freq,min); store_one(scaling_max_freq,max); /** * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware */ static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf) { unsigned int cur_freq = cpufreq_get(policy->cpu); if (!cur_freq) return sprintf(buf, "<unknown>"); return sprintf(buf, "%u\n", cur_freq); } /** * show_scaling_governor - show the current policy for the specified CPU */ static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf) { if(policy->policy == CPUFREQ_POLICY_POWERSAVE) return sprintf(buf, "powersave\n"); else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) return sprintf(buf, "performance\n"); else if (policy->governor) return scnprintf(buf, CPUFREQ_NAME_LEN, "%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; lock_cpu_hotplug(); /* Do not use cpufreq_set_policy here or the user_policy.max will be wrongly overridden */ mutex_lock(&policy->lock); ret = __cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; mutex_unlock(&policy->lock); unlock_cpu_hotplug(); return ret ? ret : count; } /** * show_scaling_driver - show the cpufreq driver currently loaded */ static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf) { return scnprintf(buf, CPUFREQ_NAME_LEN, "%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_LEN, "%s ", t->name); } out: i += sprintf(&buf[i], "\n"); return i; } /** * show_affected_cpus - show the CPUs affected by each transition */ static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf) { ssize_t i = 0; unsigned int cpu; for_each_cpu_mask(cpu, policy->cpus) { 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; } #define define_one_ro(_name) \ static struct freq_attr _name = \ __ATTR(_name, 0444, show_##_name, NULL) #define define_one_ro0400(_name) \ static struct freq_attr _name = \ __ATTR(_name, 0400, show_##_name, NULL) #define define_one_rw(_name) \ static struct freq_attr _name = \ __ATTR(_name, 0644, show_##_name, store_##_name) define_one_ro0400(cpuinfo_cur_freq); define_one_ro(cpuinfo_min_freq); define_one_ro(cpuinfo_max_freq); define_one_ro(scaling_available_governors); define_one_ro(scaling_driver); define_one_ro(scaling_cur_freq); define_one_ro(affected_cpus); define_one_rw(scaling_min_freq); define_one_rw(scaling_max_freq); define_one_rw(scaling_governor); static struct attribute * default_attrs[] = { &cpuinfo_min_freq.attr, &cpuinfo_max_freq.attr, &scaling_min_freq.attr, &scaling_max_freq.attr, &affected_cpus.attr, &scaling_governor.attr, &scaling_driver.attr, &scaling_available_governors.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; policy = cpufreq_cpu_get(policy->cpu); if (!policy) return -EINVAL; ret = fattr->show ? fattr->show(policy,buf) : -EIO; cpufreq_cpu_put(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; policy = cpufreq_cpu_get(policy->cpu); if (!policy) return -EINVAL; ret = fattr->store ? fattr->store(policy,buf,count) : -EIO; cpufreq_cpu_put(policy); return ret; } static void cpufreq_sysfs_release(struct kobject * kobj) { struct cpufreq_policy * policy = to_policy(kobj); dprintk("last reference is dropped\n"); complete(&policy->kobj_unregister); } static 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, }; /** * cpufreq_add_dev - add a CPU device * * Adds the cpufreq interface for a CPU device. */ static int cpufreq_add_dev (struct sys_device * sys_dev) { unsigned int cpu = sys_dev->id; int ret = 0; struct cpufreq_policy new_policy; struct cpufreq_policy *policy; struct freq_attr **drv_attr; struct sys_device *cpu_sys_dev; unsigned long flags; unsigned int j; #ifdef CONFIG_SMP struct cpufreq_policy *managed_policy; #endif if (cpu_is_offline(cpu)) return 0; cpufreq_debug_disable_ratelimit(); dprintk("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); cpufreq_debug_enable_ratelimit(); return 0; } #endif if (!try_module_get(cpufreq_driver->owner)) { ret = -EINVAL; goto module_out; } policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); if (!policy) { ret = -ENOMEM; goto nomem_out; } policy->cpu = cpu; policy->cpus = cpumask_of_cpu(cpu); mutex_init(&policy->lock); mutex_lock(&policy->lock); init_completion(&policy->kobj_unregister); INIT_WORK(&policy->update, handle_update, (void *)(long)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) { dprintk("initialization failed\n"); mutex_unlock(&policy->lock); goto err_out; } #ifdef CONFIG_SMP for_each_cpu_mask(j, policy->cpus) { if (cpu == j) continue; /* check for existing affected CPUs. They may not be aware * of it due to CPU Hotplug. */ managed_policy = cpufreq_cpu_get(j); if (unlikely(managed_policy)) { spin_lock_irqsave(&cpufreq_driver_lock, flags); managed_policy->cpus = policy->cpus; cpufreq_cpu_data[cpu] = managed_policy; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); dprintk("CPU already managed, adding link\n"); sysfs_create_link(&sys_dev->kobj, &managed_policy->kobj, "cpufreq"); cpufreq_debug_enable_ratelimit(); mutex_unlock(&policy->lock); ret = 0; goto err_out_driver_exit; /* call driver->exit() */ } } #endif memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); /* prepare interface data */ policy->kobj.parent = &sys_dev->kobj; policy->kobj.ktype = &ktype_cpufreq; strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN); ret = kobject_register(&policy->kobj); if (ret) { mutex_unlock(&policy->lock); goto err_out_driver_exit; } /* set up files for this cpu device */ drv_attr = cpufreq_driver->attr; while ((drv_attr) && (*drv_attr)) { sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); drv_attr++; } if (cpufreq_driver->get) sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); if (cpufreq_driver->target) sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); spin_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu_mask(j, policy->cpus) cpufreq_cpu_data[j] = policy; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); /* symlink affected CPUs */ for_each_cpu_mask(j, policy->cpus) { if (j == cpu) continue; if (!cpu_online(j)) continue; dprintk("CPU %u already managed, adding link\n", j); cpufreq_cpu_get(cpu); cpu_sys_dev = get_cpu_sysdev(j); sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj, "cpufreq"); } policy->governor = NULL; /* to assure that the starting sequence is * run in cpufreq_set_policy */ mutex_unlock(&policy->lock); /* set default policy */ ret = cpufreq_set_policy(&new_policy); if (ret) { dprintk("setting policy failed\n"); goto err_out_unregister; } module_put(cpufreq_driver->owner); dprintk("initialization complete\n"); cpufreq_debug_enable_ratelimit(); return 0; err_out_unregister: spin_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu_mask(j, policy->cpus) cpufreq_cpu_data[j] = NULL; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); kobject_unregister(&policy->kobj); wait_for_completion(&policy->kobj_unregister); err_out_driver_exit: if (cpufreq_driver->exit) cpufreq_driver->exit(policy); err_out: kfree(policy); nomem_out: module_put(cpufreq_driver->owner); module_out: cpufreq_debug_enable_ratelimit(); return ret; } /** * cpufreq_remove_dev - remove a CPU device * * Removes the cpufreq interface for a CPU device. */ static int cpufreq_remove_dev (struct sys_device * sys_dev) { unsigned int cpu = sys_dev->id; unsigned long flags; struct cpufreq_policy *data; #ifdef CONFIG_SMP struct sys_device *cpu_sys_dev; unsigned int j; #endif cpufreq_debug_disable_ratelimit(); dprintk("unregistering CPU %u\n", cpu); spin_lock_irqsave(&cpufreq_driver_lock, flags); data = cpufreq_cpu_data[cpu]; if (!data) { spin_unlock_irqrestore(&cpufreq_driver_lock, flags); cpufreq_debug_enable_ratelimit(); return -EINVAL; } 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)) { dprintk("removing link\n"); cpu_clear(cpu, data->cpus); spin_unlock_irqrestore(&cpufreq_driver_lock, flags); sysfs_remove_link(&sys_dev->kobj, "cpufreq"); cpufreq_cpu_put(data); cpufreq_debug_enable_ratelimit(); return 0; } #endif if (!kobject_get(&data->kobj)) { spin_unlock_irqrestore(&cpufreq_driver_lock, flags); cpufreq_debug_enable_ratelimit(); return -EFAULT; } #ifdef CONFIG_SMP /* if we have other CPUs still registered, we need to unlink them, * or else wait_for_completion below will lock up. Clean the * cpufreq_cpu_data[] while holding the lock, and remove the sysfs * links afterwards. */ if (unlikely(cpus_weight(data->cpus) > 1)) { for_each_cpu_mask(j, data->cpus) { if (j == cpu) continue; cpufreq_cpu_data[j] = NULL; } } spin_unlock_irqrestore(&cpufreq_driver_lock, flags); if (unlikely(cpus_weight(data->cpus) > 1)) { for_each_cpu_mask(j, data->cpus) { if (j == cpu) continue; dprintk("removing link for cpu %u\n", j); cpu_sys_dev = get_cpu_sysdev(j); sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq"); cpufreq_cpu_put(data); } } #else spin_unlock_irqrestore(&cpufreq_driver_lock, flags); #endif mutex_lock(&data->lock); if (cpufreq_driver->target) __cpufreq_governor(data, CPUFREQ_GOV_STOP); mutex_unlock(&data->lock); kobject_unregister(&data->kobj); kobject_put(&data->kobj); /* we need to make sure that the underlying kobj is actually * not referenced anymore by anybody before we proceed with * unloading. */ dprintk("waiting for dropping of refcount\n"); wait_for_completion(&data->kobj_unregister); dprintk("wait complete\n"); if (cpufreq_driver->exit) cpufreq_driver->exit(data); kfree(data); cpufreq_debug_enable_ratelimit(); return 0; } static void handle_update(void *data) { unsigned int cpu = (unsigned int)(long)data; dprintk("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; dprintk("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) frpm 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 = 0; if (policy) { mutex_lock(&policy->lock); ret = policy->cur; mutex_unlock(&policy->lock); cpufreq_cpu_put(policy); } return (ret); } EXPORT_SYMBOL(cpufreq_quick_get); /** * 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 = 0; if (!policy) return 0; if (!cpufreq_driver->get) goto out; mutex_lock(&policy->lock); ret = cpufreq_driver->get(cpu); if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { /* verify no discrepancy between actual and saved value exists */ if (unlikely(ret != policy->cur)) { cpufreq_out_of_sync(cpu, policy->cur, ret); schedule_work(&policy->update); } } mutex_unlock(&policy->lock); out: cpufreq_cpu_put(policy); return (ret); } EXPORT_SYMBOL(cpufreq_get); /** * cpufreq_suspend - let the low level driver prepare for suspend */ static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg) { int cpu = sysdev->id; unsigned int ret = 0; unsigned int cur_freq = 0; struct cpufreq_policy *cpu_policy; dprintk("suspending cpu %u\n", cpu); if (!cpu_online(cpu)) return 0; /* we may be lax here as interrupts are off. Nonetheless * we need to grab the correct cpu policy, as to check * whether we really run on this CPU. */ cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return -EINVAL; /* only handle each CPU group once */ if (unlikely(cpu_policy->cpu != cpu)) { cpufreq_cpu_put(cpu_policy); return 0; } if (cpufreq_driver->suspend) { ret = cpufreq_driver->suspend(cpu_policy, pmsg); 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; } } if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS) goto out; if (cpufreq_driver->get) cur_freq = cpufreq_driver->get(cpu_policy->cpu); if (!cur_freq || !cpu_policy->cur) { printk(KERN_ERR "cpufreq: suspend failed to assert current " "frequency is what timing core thinks it is.\n"); goto out; } if (unlikely(cur_freq != cpu_policy->cur)) { struct cpufreq_freqs freqs; if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) dprintk("Warning: CPU frequency is %u, " "cpufreq assumed %u kHz.\n", cur_freq, cpu_policy->cur); freqs.cpu = cpu; freqs.old = cpu_policy->cur; freqs.new = cur_freq; srcu_notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_SUSPENDCHANGE, &freqs); adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs); cpu_policy->cur = cur_freq; } out: cpufreq_cpu_put(cpu_policy); return 0; } /** * cpufreq_resume - restore proper CPU frequency handling after resume * * 1.) resume CPUfreq hardware support (cpufreq_driver->resume()) * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are * restored. */ static int cpufreq_resume(struct sys_device * sysdev) { int cpu = sysdev->id; unsigned int ret = 0; struct cpufreq_policy *cpu_policy; dprintk("resuming cpu %u\n", cpu); if (!cpu_online(cpu)) return 0; /* we may be lax here as interrupts are off. Nonetheless * we need to grab the correct cpu policy, as to check * whether we really run on this CPU. */ cpu_policy = cpufreq_cpu_get(cpu); if (!cpu_policy) return -EINVAL; /* only handle each CPU group once */ if (unlikely(cpu_policy->cpu != cpu)) { cpufreq_cpu_put(cpu_policy); return 0; } 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); cpufreq_cpu_put(cpu_policy); return ret; } } if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { unsigned int cur_freq = 0; if (cpufreq_driver->get) cur_freq = cpufreq_driver->get(cpu_policy->cpu); if (!cur_freq || !cpu_policy->cur) { printk(KERN_ERR "cpufreq: resume failed to assert " "current frequency is what timing core " "thinks it is.\n"); goto out; } if (unlikely(cur_freq != cpu_policy->cur)) { struct cpufreq_freqs freqs; if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) dprintk("Warning: CPU frequency" "is %u, cpufreq assumed %u kHz.\n", cur_freq, cpu_policy->cur); freqs.cpu = cpu; freqs.old = cpu_policy->cur; freqs.new = cur_freq; srcu_notifier_call_chain( &cpufreq_transition_notifier_list, CPUFREQ_RESUMECHANGE, &freqs); adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs); cpu_policy->cur = cur_freq; } } out: schedule_work(&cpu_policy->update); cpufreq_cpu_put(cpu_policy); return ret; } static struct sysdev_driver cpufreq_sysdev_driver = { .add = cpufreq_add_dev, .remove = cpufreq_remove_dev, .suspend = cpufreq_suspend, .resume = cpufreq_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; 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 * *********************************************************************/ /* Must be called with lock_cpu_hotplug held */ int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int retval = -EINVAL; dprintk("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; policy = cpufreq_cpu_get(policy->cpu); if (!policy) return -EINVAL; lock_cpu_hotplug(); mutex_lock(&policy->lock); ret = __cpufreq_driver_target(policy, target_freq, relation); mutex_unlock(&policy->lock); unlock_cpu_hotplug(); cpufreq_cpu_put(policy); return ret; } EXPORT_SYMBOL_GPL(cpufreq_driver_target); /* * Locking: Must be called with the lock_cpu_hotplug() lock held * when "event" is CPUFREQ_GOV_LIMITS */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event) { int ret; if (!try_module_get(policy->governor->owner)) return -EINVAL; dprintk("__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; 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) { if (!governor) return; 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; mutex_lock(&cpu_policy->lock); memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); mutex_unlock(&cpu_policy->lock); cpufreq_cpu_put(cpu_policy); return 0; } EXPORT_SYMBOL(cpufreq_get_policy); /* * Locking: Must be called with the lock_cpu_hotplug() lock held */ static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy) { int ret = 0; cpufreq_debug_disable_ratelimit(); dprintk("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->min && policy->min > policy->max) { 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; dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max); if (cpufreq_driver->setpolicy) { data->policy = policy->policy; dprintk("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; dprintk("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 */ dprintk("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 */ } dprintk("governor: change or update limits\n"); __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); } error_out: cpufreq_debug_enable_ratelimit(); return ret; } /** * cpufreq_set_policy - set a new CPUFreq policy * @policy: policy to be set. * * Sets a new CPU frequency and voltage scaling policy. */ int cpufreq_set_policy(struct cpufreq_policy *policy) { int ret = 0; struct cpufreq_policy *data; if (!policy) return -EINVAL; data = cpufreq_cpu_get(policy->cpu); if (!data) return -EINVAL; lock_cpu_hotplug(); /* lock this CPU */ mutex_lock(&data->lock); ret = __cpufreq_set_policy(data, policy); data->user_policy.min = data->min; data->user_policy.max = data->max; data->user_policy.policy = data->policy; data->user_policy.governor = data->governor; mutex_unlock(&data->lock); unlock_cpu_hotplug(); cpufreq_cpu_put(data); return ret; } EXPORT_SYMBOL(cpufreq_set_policy); /** * cpufreq_update_policy - re-evaluate an existing cpufreq policy * @cpu: CPU which shall be re-evaluated * * Usefull 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 = 0; if (!data) return -ENODEV; lock_cpu_hotplug(); mutex_lock(&data->lock); dprintk("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) { dprintk("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); mutex_unlock(&data->lock); unlock_cpu_hotplug(); cpufreq_cpu_put(data); return ret; } EXPORT_SYMBOL(cpufreq_update_policy); #ifdef CONFIG_HOTPLUG_CPU static int cpufreq_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; struct cpufreq_policy *policy; struct sys_device *sys_dev; sys_dev = get_cpu_sysdev(cpu); if (sys_dev) { switch (action) { case CPU_ONLINE: cpufreq_add_dev(sys_dev); break; case CPU_DOWN_PREPARE: /* * We attempt to put this cpu in lowest frequency * possible before going down. This will permit * hardware-managed P-State to switch other related * threads to min or higher speeds if possible. */ policy = cpufreq_cpu_data[cpu]; if (policy) { cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_H); } break; case CPU_DEAD: cpufreq_remove_dev(sys_dev); break; } } return NOTIFY_OK; } static struct notifier_block __cpuinitdata cpufreq_cpu_notifier = { .notifier_call = cpufreq_cpu_callback, }; #endif /* CONFIG_HOTPLUG_CPU */ /********************************************************************* * 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 (!driver_data || !driver_data->verify || !driver_data->init || ((!driver_data->setpolicy) && (!driver_data->target))) return -EINVAL; dprintk("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 = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver); if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) { int i; ret = -ENODEV; /* check for at least one working CPU */ for (i=0; i<NR_CPUS; i++) if (cpufreq_cpu_data[i]) ret = 0; /* if all ->init() calls failed, unregister */ if (ret) { dprintk("no CPU initialized for driver %s\n", driver_data->name); sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver); spin_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); } } if (!ret) { register_hotcpu_notifier(&cpufreq_cpu_notifier); dprintk("driver %s up and running\n", driver_data->name); cpufreq_debug_enable_ratelimit(); } 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; cpufreq_debug_disable_ratelimit(); if (!cpufreq_driver || (driver != cpufreq_driver)) { cpufreq_debug_enable_ratelimit(); return -EINVAL; } dprintk("unregistering driver %s\n", driver->name); sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver); 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);