diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 1428 |
1 files changed, 1428 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c new file mode 100644 index 000000000000..b30001f31610 --- /dev/null +++ b/drivers/cpufreq/cpufreq.c @@ -0,0 +1,1428 @@ +/* + * linux/drivers/cpufreq/cpufreq.c + * + * Copyright (C) 2001 Russell King + * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> + * + * 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/config.h> +#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> + +#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg) + +/** + * The "cpufreq driver" - the arch- or hardware-dependend 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); + + +/* we keep a copy of all ->add'ed CPU's struct sys_device here; + * as it is only accessed in ->add and ->remove, no lock or reference + * count is necessary. + */ +static struct sys_device *cpu_sys_devices[NR_CPUS]; + + +/* internal prototypes */ +static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); +static void handle_update(void *data); +static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci); + +/** + * 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 struct notifier_block *cpufreq_policy_notifier_list; +static struct notifier_block *cpufreq_transition_notifier_list; +static DECLARE_RWSEM (cpufreq_notifier_rwsem); + + +static LIST_HEAD(cpufreq_governor_list); +static DECLARE_MUTEX (cpufreq_governor_sem); + +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 inline 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 inline 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 inline 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)) { + 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) +{ + BUG_ON(irqs_disabled()); + + freqs->flags = cpufreq_driver->flags; + dprintk("notification %u of frequency transition to %u kHz\n", state, freqs->new); + + down_read(&cpufreq_notifier_rwsem); + 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 ((likely(cpufreq_cpu_data[freqs->cpu])) && + (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)) && + (likely(cpufreq_cpu_data[freqs->cpu]->cur)) && + (unlikely(freqs->old != cpufreq_cpu_data[freqs->cpu]->cur))) + { + printk(KERN_WARNING "Warning: CPU frequency is %u, " + "cpufreq assumed %u kHz.\n", freqs->old, cpufreq_cpu_data[freqs->cpu]->cur); + freqs->old = cpufreq_cpu_data[freqs->cpu]->cur; + } + } + notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs); + adjust_jiffies(CPUFREQ_PRECHANGE, freqs); + break; + case CPUFREQ_POSTCHANGE: + adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); + notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs); + if ((likely(cpufreq_cpu_data[freqs->cpu])) && + (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu))) + cpufreq_cpu_data[freqs->cpu]->cur = freqs->new; + break; + } + up_read(&cpufreq_notifier_rwsem); +} +EXPORT_SYMBOL_GPL(cpufreq_notify_transition); + + + +/********************************************************************* + * SYSFS INTERFACE * + *********************************************************************/ + +/** + * cpufreq_parse_governor - parse a governor string + */ +static int cpufreq_parse_governor (char *str_governor, unsigned int *policy, + struct cpufreq_governor **governor) +{ + if (!cpufreq_driver) + return -EINVAL; + if (cpufreq_driver->setpolicy) { + if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { + *policy = CPUFREQ_POLICY_PERFORMANCE; + return 0; + } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) { + *policy = CPUFREQ_POLICY_POWERSAVE; + return 0; + } + return -EINVAL; + } else { + struct cpufreq_governor *t; + down(&cpufreq_governor_sem); + if (!cpufreq_driver || !cpufreq_driver->target) + goto out; + list_for_each_entry(t, &cpufreq_governor_list, governor_list) { + if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) { + *governor = t; + up(&cpufreq_governor_sem); + return 0; + } + } + out: + up(&cpufreq_governor_sem); + } + return -EINVAL; +} +EXPORT_SYMBOL_GPL(cpufreq_parse_governor); + + +/* 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); + +/** + * 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(&new_policy); \ + \ + 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; + + ret = cpufreq_set_policy(&new_policy); + + 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) : 0; + 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) : 0; + 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; + unsigned long flags; + unsigned int j; + + 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)) { + cpu_sys_devices[cpu] = sys_dev; + dprintk("CPU already managed, adding link\n"); + sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq"); + cpufreq_debug_enable_ratelimit(); + return 0; + } +#endif + + if (!try_module_get(cpufreq_driver->owner)) { + ret = -EINVAL; + goto module_out; + } + + policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); + if (!policy) { + ret = -ENOMEM; + goto nomem_out; + } + memset(policy, 0, sizeof(struct cpufreq_policy)); + + policy->cpu = cpu; + policy->cpus = cpumask_of_cpu(cpu); + + init_MUTEX_LOCKED(&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"); + goto err_out; + } + + 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) + goto err_out; + + /* 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); + policy->governor = NULL; /* to assure that the starting sequence is + * run in cpufreq_set_policy */ + up(&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); + cpu_sys_devices[cpu] = sys_dev; + 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: + 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 + 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); + cpu_sys_devices[cpu] = NULL; + 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"); + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + sysfs_remove_link(&sys_dev->kobj, "cpufreq"); + cpu_sys_devices[cpu] = NULL; + cpufreq_cpu_put(data); + cpufreq_debug_enable_ratelimit(); + return 0; + } +#endif + + cpu_sys_devices[cpu] = NULL; + + 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); + sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq"); + cpufreq_cpu_put(data); + } + } +#else + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); +#endif + + down(&data->lock); + if (cpufreq_driver->target) + __cpufreq_governor(data, CPUFREQ_GOV_STOP); + cpufreq_driver->target = NULL; + up(&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; + + printk(KERN_WARNING "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_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; + + down(&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); + } + } + + up(&policy->lock); + + out: + cpufreq_cpu_put(policy); + + return (ret); +} +EXPORT_SYMBOL(cpufreq_get); + + +/** + * 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; + + printk(KERN_WARNING "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; + + 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, + .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 + * notifier_chain_register. + */ +int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) +{ + int ret; + + down_write(&cpufreq_notifier_rwsem); + switch (list) { + case CPUFREQ_TRANSITION_NOTIFIER: + ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb); + break; + case CPUFREQ_POLICY_NOTIFIER: + ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb); + break; + default: + ret = -EINVAL; + } + up_write(&cpufreq_notifier_rwsem); + + 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 + * notifier_chain_unregister. + */ +int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) +{ + int ret; + + down_write(&cpufreq_notifier_rwsem); + switch (list) { + case CPUFREQ_TRANSITION_NOTIFIER: + ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb); + break; + case CPUFREQ_POLICY_NOTIFIER: + ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb); + break; + default: + ret = -EINVAL; + } + up_write(&cpufreq_notifier_rwsem); + + 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; + lock_cpu_hotplug(); + 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); + unlock_cpu_hotplug(); + return retval; +} +EXPORT_SYMBOL_GPL(__cpufreq_driver_target); + + +int cpufreq_driver_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + unsigned int ret; + + policy = cpufreq_cpu_get(policy->cpu); + if (!policy) + return -EINVAL; + + down(&policy->lock); + + ret = __cpufreq_driver_target(policy, target_freq, relation); + + up(&policy->lock); + + cpufreq_cpu_put(policy); + + return ret; +} +EXPORT_SYMBOL_GPL(cpufreq_driver_target); + + +static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event) +{ + int ret = -EINVAL; + + 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_governor(unsigned int cpu, unsigned int event) +{ + int ret = 0; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + + if (!policy) + return -EINVAL; + + down(&policy->lock); + ret = __cpufreq_governor(policy, event); + up(&policy->lock); + + cpufreq_cpu_put(policy); + + return ret; +} +EXPORT_SYMBOL_GPL(cpufreq_governor); + + +int cpufreq_register_governor(struct cpufreq_governor *governor) +{ + struct cpufreq_governor *t; + + if (!governor) + return -EINVAL; + + down(&cpufreq_governor_sem); + + list_for_each_entry(t, &cpufreq_governor_list, governor_list) { + if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) { + up(&cpufreq_governor_sem); + return -EBUSY; + } + } + list_add(&governor->governor_list, &cpufreq_governor_list); + + up(&cpufreq_governor_sem); + + return 0; +} +EXPORT_SYMBOL_GPL(cpufreq_register_governor); + + +void cpufreq_unregister_governor(struct cpufreq_governor *governor) +{ + if (!governor) + return; + + down(&cpufreq_governor_sem); + list_del(&governor->governor_list); + up(&cpufreq_governor_sem); + 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; + + down(&cpu_policy->lock); + memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); + up(&cpu_policy->lock); + + cpufreq_cpu_put(cpu_policy); + + return 0; +} +EXPORT_SYMBOL(cpufreq_get_policy); + + +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)); + + /* verify the cpu speed can be set within this limit */ + ret = cpufreq_driver->verify(policy); + if (ret) + goto error_out; + + down_read(&cpufreq_notifier_rwsem); + + /* adjust if necessary - all reasons */ + notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST, + policy); + + /* adjust if necessary - hardware incompatibility*/ + 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) { + up_read(&cpufreq_notifier_rwsem); + goto error_out; + } + + /* notification of the new policy */ + notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY, + policy); + + up_read(&cpufreq_notifier_rwsem); + + 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 this CPU */ + down(&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; + + up(&data->lock); + 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; + + down(&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; + + ret = __cpufreq_set_policy(data, &policy); + + up(&data->lock); + + cpufreq_cpu_put(data); + return ret; +} +EXPORT_SYMBOL(cpufreq_update_policy); + + +/********************************************************************* + * 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) { + 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); + + 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); |