[PATCH V4 1/2] cpufreq: ondemand: allow custom powersave_bias_target handler to be registered

[Jacob Shin <jacob.shin@amd.com>]

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>
---
 drivers/cpufreq/cpufreq_governor.h |    4 +++
 drivers/cpufreq/cpufreq_ondemand.c |   56 ++++++++++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 8 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index 6593769..8ac3353 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_GOVERNOR_H */
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 1471478..e5d1e8c 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -40,6 +40,8 @@
 
 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 +82,7 @@ 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 +147,8 @@ 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 +208,12 @@ 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 +560,7 @@ 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 +577,43 @@ static struct common_dbs_data od_dbs_cdata = {
 	.exit = od_exit,
 };
 
+static void od_set_powersave_bias(unsigned int powersave_bias)
+{
+	unsigned int cpu;
+	struct od_dbs_tuners *od_tuners;
+
+	if (!have_governor_per_policy()) {
+		od_tuners = od_dbs_cdata.gdbs_data->tuners;
+		od_tuners->powersave_bias = powersave_bias;
+		return;
+	}
+
+	for_each_online_cpu(cpu) {
+		struct cpufreq_policy *policy;
+		struct dbs_data *dbs_data;
+		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;
+	}
+}
+
+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)
 {
-- 
1.7.9.5