[PATCH 4/7] cpufreq: arm_big_little: Register an Energy Model

[Quentin Perret <quentin.perret@arm.com>]

From: Dietmar Eggemann <dietmar.eggemann@arm.com>

Now that PM_OPP provides a helper function to estimate the power
consumed by CPUs, make sure to try and register an Energy Model (EM)
from the arm_big_little CPUFreq driver, hence ensuring interested
subsystems (the task scheduler, for example) can make use of that
information when available.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
---
 drivers/cpufreq/arm_big_little.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c
index cf62a1f64dd7..803d41c629c3 100644
--- a/drivers/cpufreq/arm_big_little.c
+++ b/drivers/cpufreq/arm_big_little.c
@@ -24,6 +24,7 @@
 #include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/cpu_cooling.h>
+#include <linux/energy_model.h>
 #include <linux/export.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -456,6 +457,7 @@ static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
 /* Per-CPU initialization */
 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 {
+	struct em_data_callback em_cb = EM_DATA_CB(of_dev_pm_opp_get_cpu_power);
 	u32 cur_cluster = cpu_to_cluster(policy->cpu);
 	struct device *cpu_dev;
 	int ret;
@@ -487,6 +489,14 @@ static int bL_cpufreq_init(struct cpufreq_policy *policy)
 	policy->cpuinfo.transition_latency =
 				arm_bL_ops->get_transition_latency(cpu_dev);
 
+	ret = dev_pm_opp_get_opp_count(cpu_dev);
+	if (ret <= 0) {
+		dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
+		return -EPROBE_DEFER;
+	}
+
+	em_register_perf_domain(policy->cpus, ret, &em_cb);
+
 	if (is_bL_switching_enabled())
 		per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu);
 
-- 
2.20.1