in cpufreq.c [1318:1545]
static int cpufreq_online(unsigned int cpu)
{
struct cpufreq_policy *policy;
bool new_policy;
unsigned long flags;
unsigned int j;
int ret;
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) {
WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
if (!policy_is_inactive(policy))
return cpufreq_add_policy_cpu(policy, cpu);
/* 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)
return -ENOMEM;
}
if (!new_policy && cpufreq_driver->online) {
ret = cpufreq_driver->online(policy);
if (ret) {
pr_debug("%s: %d: initialization failed\n", __func__,
__LINE__);
goto out_exit_policy;
}
/* Recover policy->cpus using related_cpus */
cpumask_copy(policy->cpus, policy->related_cpus);
} else {
cpumask_copy(policy->cpus, cpumask_of(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) {
pr_debug("%s: %d: initialization failed\n", __func__,
__LINE__);
goto out_free_policy;
}
/*
* The initialization has succeeded and the policy is online.
* If there is a problem with its frequency table, take it
* offline and drop it.
*/
ret = cpufreq_table_validate_and_sort(policy);
if (ret)
goto out_offline_policy;
/* related_cpus should at least include policy->cpus. */
cpumask_copy(policy->related_cpus, policy->cpus);
}
down_write(&policy->rwsem);
/*
* affected cpus must always be the one, which are online. We aren't
* managing offline cpus here.
*/
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
if (new_policy) {
for_each_cpu(j, policy->related_cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
add_cpu_dev_symlink(policy, j, get_cpu_device(j));
}
policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
GFP_KERNEL);
if (!policy->min_freq_req) {
ret = -ENOMEM;
goto out_destroy_policy;
}
ret = freq_qos_add_request(&policy->constraints,
policy->min_freq_req, FREQ_QOS_MIN,
FREQ_QOS_MIN_DEFAULT_VALUE);
if (ret < 0) {
/*
* So we don't call freq_qos_remove_request() for an
* uninitialized request.
*/
kfree(policy->min_freq_req);
policy->min_freq_req = NULL;
goto out_destroy_policy;
}
/*
* This must be initialized right here to avoid calling
* freq_qos_remove_request() on uninitialized request in case
* of errors.
*/
policy->max_freq_req = policy->min_freq_req + 1;
ret = freq_qos_add_request(&policy->constraints,
policy->max_freq_req, FREQ_QOS_MAX,
FREQ_QOS_MAX_DEFAULT_VALUE);
if (ret < 0) {
policy->max_freq_req = NULL;
goto out_destroy_policy;
}
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
}
if (cpufreq_driver->get && has_target()) {
policy->cur = cpufreq_driver->get(policy->cpu);
if (!policy->cur) {
ret = -EIO;
pr_err("%s: ->get() failed\n", __func__);
goto out_destroy_policy;
}
}
/*
* Sometimes boot loaders set CPU frequency to a value outside of
* frequency table present with cpufreq core. In such cases CPU might be
* unstable if it has to run on that frequency for long duration of time
* and so its better to set it to a frequency which is specified in
* freq-table. This also makes cpufreq stats inconsistent as
* cpufreq-stats would fail to register because current frequency of CPU
* isn't found in freq-table.
*
* Because we don't want this change to effect boot process badly, we go
* for the next freq which is >= policy->cur ('cur' must be set by now,
* otherwise we will end up setting freq to lowest of the table as 'cur'
* is initialized to zero).
*
* We are passing target-freq as "policy->cur - 1" otherwise
* __cpufreq_driver_target() would simply fail, as policy->cur will be
* equal to target-freq.
*/
if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
&& has_target()) {
unsigned int old_freq = policy->cur;
/* Are we running at unknown frequency ? */
ret = cpufreq_frequency_table_get_index(policy, old_freq);
if (ret == -EINVAL) {
ret = __cpufreq_driver_target(policy, old_freq - 1,
CPUFREQ_RELATION_L);
/*
* Reaching here after boot in a few seconds may not
* mean that system will remain stable at "unknown"
* frequency for longer duration. Hence, a BUG_ON().
*/
BUG_ON(ret);
pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
__func__, policy->cpu, old_freq, policy->cur);
}
}
if (new_policy) {
ret = cpufreq_add_dev_interface(policy);
if (ret)
goto out_destroy_policy;
cpufreq_stats_create_table(policy);
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_add(&policy->policy_list, &cpufreq_policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
/*
* Register with the energy model before
* sched_cpufreq_governor_change() is called, which will result
* in rebuilding of the sched domains, which should only be done
* once the energy model is properly initialized for the policy
* first.
*
* Also, this should be called before the policy is registered
* with cooling framework.
*/
if (cpufreq_driver->register_em)
cpufreq_driver->register_em(policy);
}
ret = cpufreq_init_policy(policy);
if (ret) {
pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
__func__, cpu, ret);
goto out_destroy_policy;
}
up_write(&policy->rwsem);
kobject_uevent(&policy->kobj, KOBJ_ADD);
if (cpufreq_thermal_control_enabled(cpufreq_driver))
policy->cdev = of_cpufreq_cooling_register(policy);
pr_debug("initialization complete\n");
return 0;
out_destroy_policy:
for_each_cpu(j, policy->real_cpus)
remove_cpu_dev_symlink(policy, get_cpu_device(j));
up_write(&policy->rwsem);
out_offline_policy:
if (cpufreq_driver->offline)
cpufreq_driver->offline(policy);
out_exit_policy:
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
out_free_policy:
cpufreq_policy_free(policy);
return ret;
}