linux-kernel - [PATCH] cpufreq: scmi: Fix frequency invariance in slow path

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Date:   Wed,  9 Jan 2019 10:42:36 +0000
From:   Quentin Perret <quentin.perret@....com>
To:     sudeep.holla@....com, rjw@...ysocki.net, viresh.kumar@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, dietmar.eggemann@....com,
        qais.yousef@....com, quentin.perret@....com
Subject: [PATCH] cpufreq: scmi: Fix frequency invariance in slow path

The scmi-cpufreq driver calls the arch_set_freq_scale() callback on
frequency changes to provide scale-invariant load-tracking signals to
the scheduler. However, in the slow path, it does so while specifying
the current and max frequencies in different units, hence resulting in a
broken freq_scale factor.

Fix this by passing all frequencies in KHz, as stored in the CPUFreq
frequency table.

Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI
message protocol")
Signed-off-by: Quentin Perret <quentin.perret@....com>
---
 drivers/cpufreq/scmi-cpufreq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index 50b1551ba894..3f0693439486 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -52,9 +52,9 @@ scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
 	int ret;
 	struct scmi_data *priv = policy->driver_data;
 	struct scmi_perf_ops *perf_ops = handle->perf_ops;
-	u64 freq = policy->freq_table[index].frequency * 1000;
+	u64 freq = policy->freq_table[index].frequency;
 
-	ret = perf_ops->freq_set(handle, priv->domain_id, freq, false);
+	ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
 	if (!ret)
 		arch_set_freq_scale(policy->related_cpus, freq,
 				    policy->cpuinfo.max_freq);
-- 
2.20.1