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-rw-r--r--drivers/cpufreq/cpufreq.c16
-rw-r--r--include/linux/cpufreq.h5
2 files changed, 21 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 4d5fe777184a..570bf2ebe9d4 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -61,6 +61,12 @@ static struct cpufreq_driver *cpufreq_driver;
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
static DEFINE_RWLOCK(cpufreq_driver_lock);
+static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
+bool cpufreq_supports_freq_invariance(void)
+{
+ return static_branch_likely(&cpufreq_freq_invariance);
+}
+
/* Flag to suspend/resume CPUFreq governors */
static bool cpufreq_suspended;
@@ -2720,6 +2726,15 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+ /*
+ * Mark support for the scheduler's frequency invariance engine for
+ * drivers that implement target(), target_index() or fast_switch().
+ */
+ if (!cpufreq_driver->setpolicy) {
+ static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
+ pr_debug("supports frequency invariance");
+ }
+
if (driver_data->setpolicy)
driver_data->flags |= CPUFREQ_CONST_LOOPS;
@@ -2789,6 +2804,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
cpus_read_lock();
subsys_interface_unregister(&cpufreq_interface);
remove_boost_sysfs_file();
+ static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
cpuhp_remove_state_nocalls_cpuslocked(hp_online);
write_lock_irqsave(&cpufreq_driver_lock, flags);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index a911e5d06845..e54767e2a68a 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -217,6 +217,7 @@ void refresh_frequency_limits(struct cpufreq_policy *policy);
void cpufreq_update_policy(unsigned int cpu);
void cpufreq_update_limits(unsigned int cpu);
bool have_governor_per_policy(void);
+bool cpufreq_supports_freq_invariance(void);
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
void cpufreq_enable_fast_switch(struct cpufreq_policy *policy);
void cpufreq_disable_fast_switch(struct cpufreq_policy *policy);
@@ -237,6 +238,10 @@ static inline unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
{
return 0;
}
+static inline bool cpufreq_supports_freq_invariance(void)
+{
+ return false;
+}
static inline void disable_cpufreq(void) { }
#endif