* 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
+ *
* 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/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-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 spinlock_t cpufreq_driver_lock = SPIN_LOCK_UNLOCKED;
+static struct cpufreq_driver *cpufreq_driver;
+static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
+static DEFINE_SPINLOCK(cpufreq_driver_lock);
-/* internal prototype */
+/* 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
* 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 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);
+static DEFINE_MUTEX (cpufreq_governor_mutex);
-static struct cpufreq_policy * cpufreq_cpu_get(unsigned int cpu)
+struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
struct cpufreq_policy *data;
unsigned long flags;
if (!kobject_get(&data->kobj))
goto err_out_put_module;
-
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
return data;
- err_out_put_module:
+err_out_put_module:
module_put(cpufreq_driver->owner);
- err_out_unlock:
+err_out_unlock:
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
- err_out:
+err_out:
return NULL;
}
+EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
-static void cpufreq_cpu_put(struct cpufreq_policy *data)
+
+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);
+
+ down_read(&cpufreq_notifier_rwsem);
+
+ 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(KERN_WARNING "Warning: CPU frequency is"
+ " %u, cpufreq assumed %u kHz.\n",
+ freqs->old, policy->cur);
+ freqs->old = policy->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(policy) && likely(policy->cpu == freqs->cpu))
+ policy->cur = freqs->new;
+ break;
+ }
+ up_read(&cpufreq_notifier_rwsem);
+}
+EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
+
+
/*********************************************************************
* SYSFS INTERFACE *
/**
* cpufreq_parse_governor - parse a governor string
*/
-int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
+static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
struct cpufreq_governor **governor)
{
if (!cpufreq_driver)
return -EINVAL;
} else {
struct cpufreq_governor *t;
- down(&cpufreq_governor_sem);
+ mutex_lock(&cpufreq_governor_mutex);
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);
+ mutex_unlock(&cpufreq_governor_mutex);
return 0;
}
}
- out:
- up(&cpufreq_governor_sem);
+out:
+ mutex_unlock(&cpufreq_governor_mutex);
}
return -EINVAL;
}
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
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
*/
return -EINVAL;
ret = cpufreq_set_policy(&new_policy);
-
return ret ? ret : count;
}
goto out;
i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
}
- out:
+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) \
-struct freq_attr _name = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = show_##_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) \
-struct freq_attr _name = { \
- .attr = { .name = __stringify(_name), .mode = 0644 }, \
- .show = show_##_name, \
- .store = store_##_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);
&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,
policy = cpufreq_cpu_get(policy->cpu);
if (!policy)
return -EINVAL;
- ret = fattr->show ? fattr->show(policy,buf) : 0;
+ ret = fattr->show ? fattr->show(policy,buf) : -EIO;
cpufreq_cpu_put(policy);
return ret;
}
policy = cpufreq_cpu_get(policy->cpu);
if (!policy)
return -EINVAL;
- ret = fattr->store ? fattr->store(policy,buf,count) : 0;
+ 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);
}
struct cpufreq_policy *policy;
struct freq_attr **drv_attr;
unsigned long flags;
+ unsigned int j;
- if (!try_module_get(cpufreq_driver->owner))
- return -EINVAL;
+ if (cpu_is_offline(cpu))
+ return 0;
- policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
+ 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)) {
+ 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 = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
if (!policy) {
ret = -ENOMEM;
goto nomem_out;
}
- memset(policy, 0, sizeof(struct cpufreq_policy));
policy->cpu = cpu;
- init_MUTEX_LOCKED(&policy->lock);
+ 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)
+ if (ret) {
+ dprintk("initialization failed\n");
+ mutex_unlock(&policy->lock);
goto err_out;
+ }
memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
ret = kobject_register(&policy->kobj);
- if (ret)
- goto err_out;
-
+ 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);
- cpufreq_cpu_data[cpu] = policy;
+ 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);
+ mutex_unlock(&policy->lock);
/* set default policy */
ret = cpufreq_set_policy(&new_policy);
- if (ret)
+ 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);
- cpufreq_cpu_data[cpu] = NULL;
+ 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;
}
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");
+ 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 (!kobject_get(&data->kobj))
- return -EFAULT;
+ 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);
* 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(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_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("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->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(KERN_DEBUG "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_SUSPENDCHANGE, &freqs);
+ adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
+
+ cpu_policy->cur = cur_freq;
+ }
+
+out:
+ cpufreq_cpu_put(cpu_policy);
return 0;
}
/**
- * cpufreq_resume - restore the CPU clock frequency after resume
+ * cpufreq_resume - restore proper CPU frequency handling after resume
*
- * Restore the CPU clock frequency so that our idea of the current
- * frequency reflects the actual hardware.
+ * 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)
{
unsigned int ret = 0;
struct cpufreq_policy *cpu_policy;
+ dprintk("resuming cpu %u\n", cpu);
+
if (!cpu_online(cpu))
return 0;
if (!cpu_policy)
return -EINVAL;
- if (cpufreq_driver->resume)
+ /* 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);
- goto out;
+ 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->setpolicy)
- ret = cpufreq_driver->setpolicy(cpu_policy);
- else
- /* CPUFREQ_RELATION_H or CPUFREQ_RELATION_L have the same effect here, as cpu_policy->cur is known
- * to be a valid and exact target frequency
- */
- ret = cpufreq_driver->target(cpu_policy, cpu_policy->cur, CPUFREQ_RELATION_H);
+ if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
+ unsigned int cur_freq = 0;
- if (ret)
- printk(KERN_ERR "cpufreq: resume failed in ->setpolicy/target step on CPU %u\n", cpu_policy->cpu);
+ 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(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,
+ .suspend = cpufreq_suspend,
.resume = cpufreq_resume,
};
unsigned int target_freq,
unsigned int relation)
{
- return cpufreq_driver->target(policy, target_freq, 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;
+ int ret;
policy = cpufreq_cpu_get(policy->cpu);
if (!policy)
return -EINVAL;
- down(&policy->lock);
+ mutex_lock(&policy->lock);
ret = __cpufreq_driver_target(policy, target_freq, relation);
- up(&policy->lock);
+ mutex_unlock(&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;
+ 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 (!policy)
return -EINVAL;
- down(&policy->lock);
+ mutex_lock(&policy->lock);
ret = __cpufreq_governor(policy, event);
- up(&policy->lock);
+ mutex_unlock(&policy->lock);
cpufreq_cpu_put(policy);
-
return ret;
}
EXPORT_SYMBOL_GPL(cpufreq_governor);
if (!governor)
return -EINVAL;
- down(&cpufreq_governor_sem);
+ mutex_lock(&cpufreq_governor_mutex);
list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
- up(&cpufreq_governor_sem);
+ mutex_unlock(&cpufreq_governor_mutex);
return -EBUSY;
}
}
list_add(&governor->governor_list, &cpufreq_governor_list);
- up(&cpufreq_governor_sem);
-
+ mutex_unlock(&cpufreq_governor_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_register_governor);
if (!governor)
return;
- down(&cpufreq_governor_sem);
+ mutex_lock(&cpufreq_governor_mutex);
list_del(&governor->governor_list);
- up(&cpufreq_governor_sem);
+ mutex_unlock(&cpufreq_governor_mutex);
return;
}
EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
if (!cpu_policy)
return -EINVAL;
- down(&cpu_policy->lock);
+ mutex_lock(&cpu_policy->lock);
memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
- up(&cpu_policy->lock);
+ mutex_unlock(&cpu_policy->lock);
cpufreq_cpu_put(cpu_policy);
-
return 0;
}
EXPORT_SYMBOL(cpufreq_get_policy);
{
int ret = 0;
- memcpy(&policy->cpuinfo,
- &data->cpuinfo,
- sizeof(struct cpufreq_cpuinfo));
+ 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);
up_read(&cpufreq_notifier_rwsem);
- data->min = policy->min;
- data->max = policy->max;
+ 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);
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);
}
/* might be a policy change, too, so fall through */
}
+ dprintk("governor: change or update limits\n");
__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
}
- error_out:
+error_out:
+ cpufreq_debug_enable_ratelimit();
return ret;
}
return -EINVAL;
/* lock this CPU */
- down(&data->lock);
+ mutex_lock(&data->lock);
ret = __cpufreq_set_policy(data, policy);
data->user_policy.min = data->min;
data->user_policy.policy = data->policy;
data->user_policy.governor = data->governor;
- up(&data->lock);
+ mutex_unlock(&data->lock);
cpufreq_cpu_put(data);
return ret;
if (!data)
return -ENODEV;
- down(&data->lock);
+ mutex_lock(&data->lock);
- memcpy(&policy,
- data,
- sizeof(struct cpufreq_policy));
+ 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);
- up(&data->lock);
+ mutex_unlock(&data->lock);
cpufreq_cpu_put(data);
return ret;
}
EXPORT_SYMBOL(cpufreq_update_policy);
-
-/*********************************************************************
- * EXTERNALLY AFFECTING FREQUENCY CHANGES *
- *********************************************************************/
-
-/**
- * adjust_jiffies - adjust the system "loops_per_jiffy"
- *
- * This function alters the system "loops_per_jiffy" for the clock
- * speed change. Note that loops_per_jiffy cannot be updated on SMP
- * systems as each CPU might be scaled differently. So, use the arch
- * per-CPU loops_per_jiffy value wherever possible.
- */
-#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)
+static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
{
- if (!l_p_j_ref_freq) {
- l_p_j_ref = loops_per_jiffy;
- l_p_j_ref_freq = ci->old;
+ 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;
+ }
}
- if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
- (val == CPUFREQ_POSTCHANGE && ci->old > ci->new))
- loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
+ return NOTIFY_OK;
}
-#else
-#define adjust_jiffies(x...) do {} while (0)
-#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)
+static struct notifier_block cpufreq_cpu_notifier =
{
- if (irqs_disabled())
- return; /* Only valid if we're in the resume process where
- * everyone knows what CPU frequency we are at */
-
- down_read(&cpufreq_notifier_rwsem);
- switch (state) {
- case CPUFREQ_PRECHANGE:
- 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);
- cpufreq_cpu_data[freqs->cpu]->cur = freqs->new;
- break;
- }
- up_read(&cpufreq_notifier_rwsem);
-}
-EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
-
-
+ .notifier_call = cpufreq_cpu_callback,
+};
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
((!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);
/* 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);
}
}
+ if (!ret) {
+ register_cpu_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);
{
unsigned long flags;
- if (!cpufreq_driver || (driver != cpufreq_driver))
+ 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_cpu_notifier(&cpufreq_cpu_notifier);
spin_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;