On 07/27/2017 11:46 PM, Viresh Kumar wrote:
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.ku...@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;
+
Seems reasonable. This is something that can be easily set by the driver.
/* 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;
Acked-by: Saravana Kannan <skan...@codeaurora.org>
--
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