* 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.
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);
unsigned long flags;
unsigned int j;
+ if (cpu_is_offline(cpu))
+ return 0;
+
cpufreq_debug_disable_ratelimit();
dprintk("adding CPU %u\n", cpu);
* 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();
goto module_out;
}
- policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
+ 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;
policy->cpus = cpumask_of_cpu(cpu);
ret = kobject_register(&policy->kobj);
if (ret)
- goto err_out;
+ goto err_out_driver_exit;
/* set up files for this cpu device */
drv_attr = cpufreq_driver->attr;
}
module_put(cpufreq_driver->owner);
- cpu_sys_devices[cpu] = sys_dev;
dprintk("initialization complete\n");
cpufreq_debug_enable_ratelimit();
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:
+module_out:
cpufreq_debug_enable_ratelimit();
return ret;
}
unsigned int cpu = sys_dev->id;
unsigned long flags;
struct cpufreq_policy *data;
+ struct sys_device *cpu_sys_dev;
#ifdef CONFIG_SMP
unsigned int j;
#endif
if (!data) {
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
- cpu_sys_devices[cpu] = NULL;
cpufreq_debug_enable_ratelimit();
return -EINVAL;
}
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);
if (j == cpu)
continue;
dprintk("removing link for cpu %u\n", j);
- sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
+ cpu_sys_dev = get_cpu_sysdev(j);
+ sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
cpufreq_cpu_put(data);
}
}
down(&data->lock);
if (cpufreq_driver->target)
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
- cpufreq_driver->target = NULL;
up(&data->lock);
kobject_unregister(&data->kobj);
unsigned int relation)
{
int retval = -EINVAL;
- lock_cpu_hotplug();
+
+ /*
+ * Converted the lock_cpu_hotplug to preempt_disable()
+ * and preempt_enable(). This is a bit kludgy and relies on how cpu
+ * hotplug works. All we need is a guarantee that cpu hotplug won't make
+ * progress on any cpu. Once we do preempt_disable(), this would ensure
+ * that hotplug threads don't get onto this cpu, thereby delaying
+ * the cpu remove process.
+ *
+ * We removed the lock_cpu_hotplug since we need to call this function
+ * via cpu hotplug callbacks, which result in locking the cpu hotplug
+ * thread itself. Agree this is not very clean, cpufreq community
+ * could improve this if required. - Ashok Raj <ashok.raj@intel.com>
+ */
+ preempt_disable();
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();
+ preempt_enable();
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)
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;
}
EXPORT_SYMBOL(cpufreq_update_policy);
+static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ struct 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 cpufreq_cpu_notifier =
+{
+ .notifier_call = cpufreq_cpu_callback,
+};
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
}
if (!ret) {
+ register_cpu_notifier(&cpufreq_cpu_notifier);
dprintk("driver %s up and running\n", driver_data->name);
cpufreq_debug_enable_ratelimit();
}
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;
git.samba.org / sfrench / cifs-2.6.git / blobdiff