On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU from policy-A can change frequency of CPUs belonging to policy-B.
This is quite common in case of ARM platforms where we don't configure any per-cpu register.
Add a flag to identify such platforms and update cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is set.
Also enable the flag for cpufreq-dt driver which is used only on ARM platforms currently.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/cpufreq-dt.c | 1 + include/linux/cpufreq.h | 18 ++++++++++++++++-- 2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c index fef3c2160691..d83ab94d041a 100644 --- a/drivers/cpufreq/cpufreq-dt.c +++ b/drivers/cpufreq/cpufreq-dt.c @@ -274,6 +274,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) transition_latency = CPUFREQ_ETERNAL;
policy->cpuinfo.transition_latency = transition_latency; + policy->dvfs_possible_from_any_cpu = true;
return 0;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index b3b6e8203e82..227cd0f13300 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -127,6 +127,15 @@ struct cpufreq_policy { */ unsigned int transition_delay_us;
+ /* + * Remote DVFS flag (Not added to the driver structure as we don't want + * to access another structure from scheduler hotpath). + * + * Should be set if CPUs can do DVFS on behalf of other CPUs from + * different cpufreq policies. + */ + bool dvfs_possible_from_any_cpu; + /* Cached frequency lookup from cpufreq_driver_resolve_freq. */ unsigned int cached_target_freq; int cached_resolved_idx; @@ -564,8 +573,13 @@ struct governor_attr {
static inline bool cpufreq_can_do_remote_dvfs(struct cpufreq_policy *policy) { - /* Allow remote callbacks only on the CPUs sharing cpufreq policy */ - if (cpumask_test_cpu(smp_processor_id(), policy->cpus)) + /* + * Allow remote callbacks if: + * - dvfs_possible_from_any_cpu flag is set + * - the local and remote CPUs share cpufreq policy + */ + if (policy->dvfs_possible_from_any_cpu || + cpumask_test_cpu(smp_processor_id(), policy->cpus)) return true;
return false; -- 2.13.0.71.gd7076ec9c9cb