linux-kernel - [PATCH v4 03/18] PM: EM: Find first CPU online while updating OPP efficiency

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Message-Id: <20230925081139.1305766-4-lukasz.luba@arm.com>
Date:   Mon, 25 Sep 2023 09:11:24 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael@...nel.org
Cc:     lukasz.luba@....com, dietmar.eggemann@....com, rui.zhang@...el.com,
        amit.kucheria@...durent.com, amit.kachhap@...il.com,
        daniel.lezcano@...aro.org, viresh.kumar@...aro.org,
        len.brown@...el.com, pavel@....cz, mhiramat@...nel.org,
        qyousef@...alina.io, wvw@...gle.com
Subject: [PATCH v4 03/18] PM: EM: Find first CPU online while updating OPP efficiency

The Energy Model might be updated at runtime and the energy efficiency
for each OPP may change. Thus, there is a need to update also the
cpufreq framework and make it aligned to the new values. In order to
do that, use a first online CPU from the Performance Domain.

Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 kernel/power/energy_model.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 42486674b834..3dafdd7731c4 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -243,12 +243,19 @@ em_cpufreq_update_efficiencies(struct device *dev, struct em_perf_state *table)
 	struct em_perf_domain *pd = dev->em_pd;
 	struct cpufreq_policy *policy;
 	int found = 0;
-	int i;
+	int i, cpu;
 
 	if (!_is_cpu_device(dev) || !pd)
 		return;
 
-	policy = cpufreq_cpu_get(cpumask_first(em_span_cpus(pd)));
+	/* Try to get a CPU which is online and in this PD */
+	cpu = cpumask_first_and(em_span_cpus(pd), cpu_active_mask);
+	if (cpu >= nr_cpu_ids) {
+		dev_warn(dev, "EM: No online CPU for CPUFreq policy\n");
+		return;
+	}
+
+	policy = cpufreq_cpu_get(cpu);
 	if (!policy) {
 		dev_warn(dev, "EM: Access to CPUFreq policy failed\n");
 		return;
-- 
2.25.1