summaryrefslogtreecommitdiff
path: root/drivers/cpufreq
diff options
context:
space:
mode:
authorViresh Kumar <viresh.kumar@linaro.org>2019-02-12 14:06:04 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-02-13 01:47:42 +0300
commit91a12e91dc39137906d929a4ff6f9c32c59697fa (patch)
tree43cb806788ec5b4fc8ff3f12445d9e5660531338 /drivers/cpufreq
parent9795607dc41e7606e90e48bffe6927bee32cd336 (diff)
downloadlinux-91a12e91dc39137906d929a4ff6f9c32c59697fa.tar.xz
cpufreq: Allow light-weight tear down and bring up of CPUs
The cpufreq core doesn't remove the cpufreq policy anymore on CPU offline operation, rather that happens when the CPU device gets unregistered from the kernel. This allows faster recovery when the CPU comes back online. This is also very useful during system wide suspend/resume where we offline all non-boot CPUs during suspend and then bring them back on resume. This commit takes the same idea a step ahead to allow drivers to do light weight tear-down and bring-up during CPU offline and online operations. A new set of callbacks is introduced, online/offline(). online() gets called when the first CPU of an inactive policy is brought up and offline() gets called when all the CPUs of a policy are offlined. The existing init/exit() callback get called on policy creation/destruction. They also get called instead of online/offline() callbacks if the online/offline() callbacks aren't provided. This also moves around some code to get executed only for the new-policy case going forward. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c58
1 files changed, 38 insertions, 20 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 96a69c67a545..55e9795801a4 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1201,28 +1201,39 @@ static int cpufreq_online(unsigned int cpu)
return -ENOMEM;
}
- cpumask_copy(policy->cpus, cpumask_of(cpu));
+ 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;
+ }
- /* 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("initialization failed\n");
- goto out_free_policy;
- }
+ /* Recover policy->cpus using related_cpus */
+ cpumask_copy(policy->cpus, policy->related_cpus);
+ } else {
+ cpumask_copy(policy->cpus, cpumask_of(cpu));
- ret = cpufreq_table_validate_and_sort(policy);
- if (ret)
- goto out_exit_policy;
+ /*
+ * 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;
+ }
- down_write(&policy->rwsem);
+ ret = cpufreq_table_validate_and_sort(policy);
+ if (ret)
+ goto out_exit_policy;
- if (new_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.
@@ -1421,11 +1432,12 @@ static int cpufreq_offline(unsigned int cpu)
cpufreq_exit_governor(policy);
/*
- * Perform the ->exit() even during light-weight tear-down,
- * since this is a core component, and is essential for the
- * subsequent light-weight ->init() to succeed.
+ * Perform the ->offline() during light-weight tear-down, as
+ * that allows fast recovery when the CPU comes back.
*/
- if (cpufreq_driver->exit) {
+ if (cpufreq_driver->offline) {
+ cpufreq_driver->offline(policy);
+ } else if (cpufreq_driver->exit) {
cpufreq_driver->exit(policy);
policy->freq_table = NULL;
}
@@ -1454,8 +1466,13 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
cpumask_clear_cpu(cpu, policy->real_cpus);
remove_cpu_dev_symlink(policy, dev);
- if (cpumask_empty(policy->real_cpus))
+ if (cpumask_empty(policy->real_cpus)) {
+ /* We did light-weight exit earlier, do full tear down now */
+ if (cpufreq_driver->offline)
+ cpufreq_driver->exit(policy);
+
cpufreq_policy_free(policy);
+ }
}
/**
@@ -2488,7 +2505,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
driver_data->target) ||
(driver_data->setpolicy && (driver_data->target_index ||
driver_data->target)) ||
- (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
+ (!!driver_data->get_intermediate != !!driver_data->target_intermediate) ||
+ (!driver_data->online != !driver_data->offline))
return -EINVAL;
pr_debug("trying to register driver %s\n", driver_data->name);