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From: Lukasz Luba <lukasz.luba@arm.com>
To: linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org,
	rafael@kernel.org
Cc: lukasz.luba@arm.com,
	dietmar.eggemann@arm.com,
	rui.zhang@intel.com,
	amit.kucheria@verdurent.com,
	amit.kachhap@gmail.com,
	daniel.lezcano@linaro.org,
	viresh.kumar@linaro.org,
	len.brown@intel.com,
	pavel@ucw.cz,
	mhiramat@kernel.org,
	qyousef@layalina.io,
	wvw@google.com,
	xuewen.yan94@gmail.com,
	Hongyan Xia <hongyan.xia2@arm.com>
Subject: [PATCH v8 03/23] PM: EM: Find first CPU active while updating OPP efficiency
Date: Thu,  8 Feb 2024 11:55:37 +0000
Message-Id: <20240208115557.1273962-4-lukasz.luba@arm.com>
In-Reply-To: <20240208115557.1273962-1-lukasz.luba@arm.com>
References: <20240208115557.1273962-1-lukasz.luba@arm.com>
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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 active CPU from the Performance Domain. This is
needed since the first CPU in the cpumask might be offline when we
run this code path.

Reviewed-by: Hongyan Xia <hongyan.xia2@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.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 8c373b151875..0c3220ff54f7 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))
 		return;
 
-	policy = cpufreq_cpu_get(cpumask_first(em_span_cpus(pd)));
+	/* Try to get a CPU which is active 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