cpufreq: Add callback to register with energy model

Many cpufreq drivers register with the energy model for each policy and
do exactly the same thing. Follow the footsteps of thermal-cooling, to
get it done from the cpufreq core itself.

Provide a new callback, which will be called, if present, by the cpufreq
core at the right moment (more on that in the code's comment). Also
provide a generic implementation that uses dev_pm_opp_of_register_em().

This also allows us to register with the EM at a later point of time,
compared to ->init(), from where the EM core can access cpufreq policy
directly using cpufreq_cpu_get() type of helpers and perform other work,
like marking few frequencies inefficient, this will be done separately.

Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 45f3416988f1a45d42bdc516105caa82702483e6..d301f39248a0d763b00c074dafdd6897c435c571 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1491,6 +1491,19 @@ static int cpufreq_online(unsigned int cpu)
                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);

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 9fd719475fcdf06ae2ade5504f708700f38415a5..c65a1d7385f80da0d54ec49f11597165db64c2d0 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -9,10 +9,12 @@
 #define _LINUX_CPUFREQ_H
 
 #include <linux/clk.h>
+#include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/completion.h>
 #include <linux/kobject.h>
 #include <linux/notifier.h>
+#include <linux/pm_opp.h>
 #include <linux/pm_qos.h>
 #include <linux/spinlock.h>
 #include <linux/sysfs.h>
@@ -373,6 +375,12 @@ struct cpufreq_driver {
        /* platform specific boost support code */
        bool            boost_enabled;
        int             (*set_boost)(struct cpufreq_policy *policy, int state);
+
+       /*
+        * Set by drivers that want to register with the energy model after the
+        * policy is properly initialized, but before the governor is started.
+        */
+       void            (*register_em)(struct cpufreq_policy *policy);
 };
 
 /* flags */
@@ -1046,4 +1054,10 @@ unsigned int cpufreq_generic_get(unsigned int cpu);
 void cpufreq_generic_init(struct cpufreq_policy *policy,
                struct cpufreq_frequency_table *table,
                unsigned int transition_latency);
+
+static inline void cpufreq_register_em_with_opp(struct cpufreq_policy *policy)
+{
+       dev_pm_opp_of_register_em(get_cpu_device(policy->cpu),
+                                 policy->related_cpus);
+}
 #endif /* _LINUX_CPUFREQ_H */