return cpufreq_driver->target_index || cpufreq_driver->target;
}
-/*
- * rwsem to guarantee that cpufreq driver module doesn't unload during critical
- * sections
- */
-static DECLARE_RWSEM(cpufreq_rwsem);
-
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy,
unsigned int event);
* If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
* freed as that depends on the kobj count.
*
- * It also takes a read-lock of 'cpufreq_rwsem' and doesn't put it back if a
- * valid policy is found. This is done to make sure the driver doesn't get
- * unregistered while the policy is being used.
- *
* Return: A valid policy on success, otherwise NULL on failure.
*/
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
if (WARN_ON(cpu >= nr_cpu_ids))
return NULL;
- if (!down_read_trylock(&cpufreq_rwsem))
- return NULL;
-
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
- if (!policy)
- up_read(&cpufreq_rwsem);
-
return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
*
* This decrements the kobject reference count incremented earlier by calling
* cpufreq_cpu_get().
- *
- * It also drops the read-lock of 'cpufreq_rwsem' taken at cpufreq_cpu_get().
*/
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
kobject_put(&policy->kobj);
- up_read(&cpufreq_rwsem);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
struct freq_attr *fattr = to_attr(attr);
ssize_t ret;
- if (!down_read_trylock(&cpufreq_rwsem))
- return -EINVAL;
-
down_read(&policy->rwsem);
if (fattr->show)
ret = -EIO;
up_read(&policy->rwsem);
- up_read(&cpufreq_rwsem);
return ret;
}
if (!cpu_online(policy->cpu))
goto unlock;
- if (!down_read_trylock(&cpufreq_rwsem))
- goto unlock;
-
down_write(&policy->rwsem);
/* Updating inactive policies is invalid, so avoid doing that. */
unlock_policy_rwsem:
up_write(&policy->rwsem);
-
- up_read(&cpufreq_rwsem);
unlock:
put_online_cpus();
int ret = 0;
/* Some related CPUs might not be present (physically hotplugged) */
- for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
+ for_each_cpu(j, policy->real_cpus) {
if (j == policy->kobj_cpu)
continue;
unsigned int j;
/* Some related CPUs might not be present (physically hotplugged) */
- for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
+ for_each_cpu(j, policy->real_cpus) {
if (j == policy->kobj_cpu)
continue;
}
}
-static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
- struct device *dev)
+static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
{
struct freq_attr **drv_attr;
int ret = 0;
return cpufreq_add_dev_symlink(policy);
}
-static void cpufreq_init_policy(struct cpufreq_policy *policy)
+static int cpufreq_init_policy(struct cpufreq_policy *policy)
{
struct cpufreq_governor *gov = NULL;
struct cpufreq_policy new_policy;
- int ret = 0;
memcpy(&new_policy, policy, sizeof(*policy));
cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
/* set default policy */
- ret = cpufreq_set_policy(policy, &new_policy);
- if (ret) {
- pr_debug("setting policy failed\n");
- if (cpufreq_driver->exit)
- cpufreq_driver->exit(policy);
- }
+ return cpufreq_set_policy(policy, &new_policy);
}
-static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
- unsigned int cpu, struct device *dev)
+static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
int ret = 0;
return 0;
}
-static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
-{
- struct cpufreq_policy *policy;
- unsigned long flags;
-
- read_lock_irqsave(&cpufreq_driver_lock, flags);
- policy = per_cpu(cpufreq_cpu_data, cpu);
- read_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
- if (likely(policy)) {
- /* Policy should be inactive here */
- WARN_ON(!policy_is_inactive(policy));
-
- down_write(&policy->rwsem);
- policy->cpu = cpu;
- policy->governor = NULL;
- up_write(&policy->rwsem);
- }
-
- return policy;
-}
-
-static struct cpufreq_policy *cpufreq_policy_alloc(struct device *dev)
+static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
{
+ struct device *dev = get_cpu_device(cpu);
struct cpufreq_policy *policy;
int ret;
+ if (WARN_ON(!dev))
+ return NULL;
+
policy = kzalloc(sizeof(*policy), GFP_KERNEL);
if (!policy)
return NULL;
if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
goto err_free_cpumask;
+ if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
+ goto err_free_rcpumask;
+
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
"cpufreq");
if (ret) {
pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
- goto err_free_rcpumask;
+ goto err_free_real_cpus;
}
INIT_LIST_HEAD(&policy->policy_list);
init_completion(&policy->kobj_unregister);
INIT_WORK(&policy->update, handle_update);
- policy->cpu = dev->id;
+ policy->cpu = cpu;
/* Set this once on allocation */
- policy->kobj_cpu = dev->id;
+ policy->kobj_cpu = cpu;
return policy;
+err_free_real_cpus:
+ free_cpumask_var(policy->real_cpus);
err_free_rcpumask:
free_cpumask_var(policy->related_cpus);
err_free_cpumask:
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
cpufreq_policy_put_kobj(policy, notify);
+ free_cpumask_var(policy->real_cpus);
free_cpumask_var(policy->related_cpus);
free_cpumask_var(policy->cpus);
kfree(policy);
}
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
- */
-static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+static int cpufreq_online(unsigned int cpu)
{
- unsigned int j, cpu = dev->id;
- int ret = -ENOMEM;
struct cpufreq_policy *policy;
+ bool new_policy;
unsigned long flags;
- bool recover_policy = !sif;
-
- pr_debug("adding CPU %u\n", cpu);
-
- /*
- * Only possible if 'cpu' wasn't physically present earlier and we are
- * here from subsys_interface add callback. A hotplug notifier will
- * follow and we will handle it like logical CPU hotplug then. For now,
- * just create the sysfs link.
- */
- if (cpu_is_offline(cpu))
- return add_cpu_dev_symlink(per_cpu(cpufreq_cpu_data, cpu), cpu);
+ unsigned int j;
+ int ret;
- if (!down_read_trylock(&cpufreq_rwsem))
- return 0;
+ pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
/* Check if this CPU already has a policy to manage it */
policy = per_cpu(cpufreq_cpu_data, cpu);
- if (policy && !policy_is_inactive(policy)) {
+ if (policy) {
WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
- ret = cpufreq_add_policy_cpu(policy, cpu, dev);
- up_read(&cpufreq_rwsem);
- return ret;
- }
+ if (!policy_is_inactive(policy))
+ return cpufreq_add_policy_cpu(policy, cpu);
- /*
- * Restore the saved policy when doing light-weight init and fall back
- * to the full init if that fails.
- */
- policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
- if (!policy) {
- recover_policy = false;
- policy = cpufreq_policy_alloc(dev);
+ /* This is the only online CPU for the policy. Start over. */
+ new_policy = false;
+ down_write(&policy->rwsem);
+ policy->cpu = cpu;
+ policy->governor = NULL;
+ up_write(&policy->rwsem);
+ } else {
+ new_policy = true;
+ policy = cpufreq_policy_alloc(cpu);
if (!policy)
- goto nomem_out;
+ return -ENOMEM;
}
cpumask_copy(policy->cpus, cpumask_of(cpu));
ret = cpufreq_driver->init(policy);
if (ret) {
pr_debug("initialization failed\n");
- goto err_set_policy_cpu;
+ goto out_free_policy;
}
down_write(&policy->rwsem);
- /* related cpus should atleast have policy->cpus */
- cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
+ if (new_policy) {
+ /* related_cpus should at least include policy->cpus. */
+ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
+ /* Remember CPUs present at the policy creation time. */
+ cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
+ }
/*
* affected cpus must always be the one, which are online. We aren't
*/
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
- if (!recover_policy) {
+ if (new_policy) {
policy->user_policy.min = policy->min;
policy->user_policy.max = policy->max;
policy->cur = cpufreq_driver->get(policy->cpu);
if (!policy->cur) {
pr_err("%s: ->get() failed\n", __func__);
- goto err_get_freq;
+ goto out_exit_policy;
}
}
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
- if (!recover_policy) {
- ret = cpufreq_add_dev_interface(policy, dev);
+ if (new_policy) {
+ ret = cpufreq_add_dev_interface(policy);
if (ret)
- goto err_out_unregister;
+ goto out_exit_policy;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
}
- cpufreq_init_policy(policy);
+ ret = cpufreq_init_policy(policy);
+ if (ret) {
+ pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
+ __func__, cpu, ret);
+ /* cpufreq_policy_free() will notify based on this */
+ new_policy = false;
+ goto out_exit_policy;
+ }
- if (!recover_policy) {
+ if (new_policy) {
policy->user_policy.policy = policy->policy;
policy->user_policy.governor = policy->governor;
}
kobject_uevent(&policy->kobj, KOBJ_ADD);
- up_read(&cpufreq_rwsem);
-
/* Callback for handling stuff after policy is ready */
if (cpufreq_driver->ready)
cpufreq_driver->ready(policy);
return 0;
-err_out_unregister:
-err_get_freq:
+out_exit_policy:
up_write(&policy->rwsem);
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
-err_set_policy_cpu:
- cpufreq_policy_free(policy, recover_policy);
-nomem_out:
- up_read(&cpufreq_rwsem);
+out_free_policy:
+ cpufreq_policy_free(policy, !new_policy);
+ return ret;
+}
+
+/**
+ * cpufreq_add_dev - the cpufreq interface for a CPU device.
+ * @dev: CPU device.
+ * @sif: Subsystem interface structure pointer (not used)
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+ unsigned cpu = dev->id;
+ int ret;
+
+ dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
+
+ if (cpu_online(cpu)) {
+ ret = cpufreq_online(cpu);
+ } else {
+ /*
+ * A hotplug notifier will follow and we will handle it as CPU
+ * online then. For now, just create the sysfs link, unless
+ * there is no policy or the link is already present.
+ */
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
+
+ ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
+ ? add_cpu_dev_symlink(policy, cpu) : 0;
+ }
return ret;
}
-static int __cpufreq_remove_dev_prepare(struct device *dev,
- struct subsys_interface *sif)
+static void cpufreq_offline_prepare(unsigned int cpu)
{
- unsigned int cpu = dev->id;
- int ret = 0;
struct cpufreq_policy *policy;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
policy = cpufreq_cpu_get_raw(cpu);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
- return -EINVAL;
+ return;
}
if (has_target()) {
- ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
- if (ret) {
+ int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ if (ret)
pr_err("%s: Failed to stop governor\n", __func__);
- return ret;
- }
}
down_write(&policy->rwsem);
/* Start governor again for active policy */
if (!policy_is_inactive(policy)) {
if (has_target()) {
- ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
if (!ret)
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
} else if (cpufreq_driver->stop_cpu) {
cpufreq_driver->stop_cpu(policy);
}
-
- return ret;
}
-static int __cpufreq_remove_dev_finish(struct device *dev,
- struct subsys_interface *sif)
+static void cpufreq_offline_finish(unsigned int cpu)
{
- unsigned int cpu = dev->id;
- int ret;
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
- return -EINVAL;
+ return;
}
/* Only proceed for inactive policies */
if (!policy_is_inactive(policy))
- return 0;
+ return;
/* If cpu is last user of policy, free policy */
if (has_target()) {
- ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
- if (ret) {
+ int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
+ if (ret)
pr_err("%s: Failed to exit governor\n", __func__);
- return ret;
- }
}
/*
*/
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
-
- /* Free the policy only if the driver is getting removed. */
- if (sif)
- cpufreq_policy_free(policy, true);
-
- return 0;
}
/**
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
- int ret;
-
- /*
- * Only possible if 'cpu' is getting physically removed now. A hotplug
- * notifier should have already been called and we just need to remove
- * link or free policy here.
- */
- if (cpu_is_offline(cpu)) {
- struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
- struct cpumask mask;
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
- if (!policy)
- return 0;
+ if (!policy)
+ return 0;
- cpumask_copy(&mask, policy->related_cpus);
- cpumask_clear_cpu(cpu, &mask);
+ if (cpu_online(cpu)) {
+ cpufreq_offline_prepare(cpu);
+ cpufreq_offline_finish(cpu);
+ }
- /*
- * Free policy only if all policy->related_cpus are removed
- * physically.
- */
- if (cpumask_intersects(&mask, cpu_present_mask)) {
- remove_cpu_dev_symlink(policy, cpu);
- return 0;
- }
+ cpumask_clear_cpu(cpu, policy->real_cpus);
+ if (cpumask_empty(policy->real_cpus)) {
cpufreq_policy_free(policy, true);
return 0;
}
- ret = __cpufreq_remove_dev_prepare(dev, sif);
+ if (cpu != policy->kobj_cpu) {
+ remove_cpu_dev_symlink(policy, cpu);
+ } else {
+ /*
+ * The CPU owning the policy object is going away. Move it to
+ * another suitable CPU.
+ */
+ unsigned int new_cpu = cpumask_first(policy->real_cpus);
+ struct device *new_dev = get_cpu_device(new_cpu);
+
+ dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
- if (!ret)
- ret = __cpufreq_remove_dev_finish(dev, sif);
+ sysfs_remove_link(&new_dev->kobj, "cpufreq");
+ policy->kobj_cpu = new_cpu;
+ WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
+ }
- return ret;
+ return 0;
}
static void handle_update(struct work_struct *work)
memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
- if (new_policy->min > policy->max || new_policy->max < policy->min)
+ /*
+ * This check works well when we store new min/max freq attributes,
+ * because new_policy is a copy of policy with one field updated.
+ */
+ if (new_policy->min > new_policy->max)
return -EINVAL;
/* verify the cpu speed can be set within this limit */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_ADJUST, new_policy);
- /* adjust if necessary - hardware incompatibility*/
- blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
- CPUFREQ_INCOMPATIBLE, new_policy);
-
/*
* verify the cpu speed can be set within this limit, which might be
* different to the first one
old_gov = policy->governor;
/* end old governor */
if (old_gov) {
- __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ if (ret) {
+ /* This can happen due to race with other operations */
+ pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
+ __func__, old_gov->name, ret);
+ return ret;
+ }
+
up_write(&policy->rwsem);
- __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
down_write(&policy->rwsem);
+
+ if (ret) {
+ pr_err("%s: Failed to Exit Governor: %s (%d)\n",
+ __func__, old_gov->name, ret);
+ return ret;
+ }
}
/* start new governor */
policy->governor = new_policy->governor;
- if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
- if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
+ if (!ret) {
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ if (!ret)
goto out;
up_write(&policy->rwsem);
pr_debug("starting governor %s failed\n", policy->governor->name);
if (old_gov) {
policy->governor = old_gov;
- __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
- __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
+ policy->governor = NULL;
+ else
+ __cpufreq_governor(policy, CPUFREQ_GOV_START);
}
- return -EINVAL;
+ return ret;
out:
pr_debug("governor: change or update limits\n");
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
- struct device *dev;
- dev = get_cpu_device(cpu);
- if (dev) {
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_ONLINE:
- cpufreq_add_dev(dev, NULL);
- break;
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ cpufreq_online(cpu);
+ break;
- case CPU_DOWN_PREPARE:
- __cpufreq_remove_dev_prepare(dev, NULL);
- break;
+ case CPU_DOWN_PREPARE:
+ cpufreq_offline_prepare(cpu);
+ break;
- case CPU_POST_DEAD:
- __cpufreq_remove_dev_finish(dev, NULL);
- break;
+ case CPU_POST_DEAD:
+ cpufreq_offline_finish(cpu);
+ break;
- case CPU_DOWN_FAILED:
- cpufreq_add_dev(dev, NULL);
- break;
- }
+ case CPU_DOWN_FAILED:
+ cpufreq_online(cpu);
+ break;
}
return NOTIFY_OK;
}
pr_debug("trying to register driver %s\n", driver_data->name);
+ /* Protect against concurrent CPU online/offline. */
+ get_online_cpus();
+
write_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return -EEXIST;
+ ret = -EEXIST;
+ goto out;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
register_hotcpu_notifier(&cpufreq_cpu_notifier);
pr_debug("driver %s up and running\n", driver_data->name);
- return 0;
+out:
+ put_online_cpus();
+ return ret;
+
err_if_unreg:
subsys_interface_unregister(&cpufreq_interface);
err_boost_unreg:
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return ret;
+ goto out;
}
EXPORT_SYMBOL_GPL(cpufreq_register_driver);
pr_debug("unregistering driver %s\n", driver->name);
+ /* Protect against concurrent cpu hotplug */
+ get_online_cpus();
subsys_interface_unregister(&cpufreq_interface);
if (cpufreq_boost_supported())
cpufreq_sysfs_remove_file(&boost.attr);
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
- down_write(&cpufreq_rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- up_write(&cpufreq_rwsem);
+ put_online_cpus();
return 0;
}
projects / linux-2.6-microblaze.git / blobdiff