cpufreq: ondemand: allow custom powersave_bias_target handler to be registered

This allows for another [arch specific] driver to hook into existing
powersave bias function of the ondemand governor. i.e. This allows AMD
specific powersave bias function (in a separate AMD specific driver)
to aid ondemand governor's frequency transition decisions.

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 57 insertions, 8 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index 513cc8234e5e..9f668e94dead 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -263,4 +263,8 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                 struct common_dbs_data *cdata, unsigned int event);
 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
                 unsigned int delay, bool all_cpus);
+void od_register_powersave_bias_handler(unsigned int (*f)
+                (struct cpufreq_policy *, unsigned int, unsigned int),
+                unsigned int powersave_bias);
+void od_unregister_powersave_bias_handler(void);
 #endif /* _CPUFREQ_GOVERNER_H */
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 14714787b724..b0ffef96bf77 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -24,6 +24,7 @@
 #include <linux/sysfs.h>
 #include <linux/tick.h>
 #include <linux/types.h>
+#include <linux/cpu.h>
 
 #include "cpufreq_governor.h"
 
@@ -40,6 +41,8 @@
 
 static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
 
+static struct od_ops od_ops;
+
 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
 static struct cpufreq_governor cpufreq_gov_ondemand;
 #endif
@@ -80,7 +83,7 @@ static int should_io_be_busy(void)
  * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
  * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
  */
-static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
+static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy,
                 unsigned int freq_next, unsigned int relation)
 {
         unsigned int freq_req, freq_reduc, freq_avg;
@@ -145,7 +148,8 @@ static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 
         if (od_tuners->powersave_bias)
-                freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H);
+                freq = od_ops.powersave_bias_target(p, freq,
+                                CPUFREQ_RELATION_H);
         else if (p->cur == p->max)
                 return;
 
@@ -205,12 +209,12 @@ static void od_check_cpu(int cpu, unsigned int load_freq)
                 if (!od_tuners->powersave_bias) {
                         __cpufreq_driver_target(policy, freq_next,
                                         CPUFREQ_RELATION_L);
-                } else {
-                        int freq = powersave_bias_target(policy, freq_next,
-                                        CPUFREQ_RELATION_L);
-                        __cpufreq_driver_target(policy, freq,
-                                        CPUFREQ_RELATION_L);
+                        return;
                 }
+
+                freq_next = od_ops.powersave_bias_target(policy, freq_next,
+                                        CPUFREQ_RELATION_L);
+                __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
         }
 }
 
@@ -557,7 +561,7 @@ define_get_cpu_dbs_routines(od_cpu_dbs_info);
 
 static struct od_ops od_ops = {
         .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu,
-        .powersave_bias_target = powersave_bias_target,
+        .powersave_bias_target = generic_powersave_bias_target,
         .freq_increase = dbs_freq_increase,
 };
 
@@ -574,6 +578,47 @@ static struct common_dbs_data od_dbs_cdata = {
         .exit = od_exit,
 };
 
+static void od_set_powersave_bias(unsigned int powersave_bias)
+{
+        struct cpufreq_policy *policy;
+        struct dbs_data *dbs_data;
+        struct od_dbs_tuners *od_tuners;
+        unsigned int cpu;
+        cpumask_t done;
+
+        cpumask_clear(&done);
+
+        get_online_cpus();
+        for_each_online_cpu(cpu) {
+                if (cpumask_test_cpu(cpu, &done))
+                        continue;
+
+                policy = per_cpu(od_cpu_dbs_info, cpu).cdbs.cur_policy;
+                dbs_data = policy->governor_data;
+                od_tuners = dbs_data->tuners;
+                od_tuners->powersave_bias = powersave_bias;
+
+                cpumask_or(&done, &done, policy->cpus);
+        }
+        put_online_cpus();
+}
+
+void od_register_powersave_bias_handler(unsigned int (*f)
+                (struct cpufreq_policy *, unsigned int, unsigned int),
+                unsigned int powersave_bias)
+{
+        od_ops.powersave_bias_target = f;
+        od_set_powersave_bias(powersave_bias);
+}
+EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler);
+
+void od_unregister_powersave_bias_handler(void)
+{
+        od_ops.powersave_bias_target = generic_powersave_bias_target;
+        od_set_powersave_bias(0);
+}
+EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler);
+
 static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy,
                 unsigned int event)
 {