Thread (5 messages) 5 messages, 3 authors, 2018-02-26

[PATCH] cpufreq: scpi: invoke frequency-invariance setter function

From: rafael@kernel.org (Rafael J. Wysocki)
Date: 2018-02-22 22:27:47
Also in: linux-pm, lkml

On Tue, Feb 20, 2018 at 12:10 PM, Dietmar Eggemann
[off-list ref] wrote:
Commit 343a8d17fa8d ("cpufreq: scpi: remove arm_big_little dependency")
changed the cpufreq driver on juno from arm_big_little to scpi.

The scpi set_target function does not call the frequency-invariance
setter function arch_set_freq_scale() like the arm_big_little set_target
function does. As a result the task scheduler load and utilization
signals are not frequency-invariant on this platform anymore.

Fix this by adding a call to arch_set_freq_scale() into
scpi_cpufreq_set_target().

Fixes: 343a8d17fa8d ("cpufreq: scpi: remove arm_big_little dependency")
Cc: Rafael J. Wysocki <redacted>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Sudeep Holla <redacted>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Sudeep Holla <redacted>
This is really minor, but I would reorder this slightly.
quoted hunk ↗ jump to hunk
---
 drivers/cpufreq/scpi-cpufreq.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/cpufreq/scpi-cpufreq.c b/drivers/cpufreq/scpi-cpufreq.c
index c32a833e1b00..3101d4e9c2de 100644
--- a/drivers/cpufreq/scpi-cpufreq.c
+++ b/drivers/cpufreq/scpi-cpufreq.c
@@ -51,13 +51,19 @@ static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
 static int
 scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
 {
+       unsigned long freq = policy->freq_table[index].frequency;
        struct scpi_data *priv = policy->driver_data;
-       u64 rate = policy->freq_table[index].frequency * 1000;
+       u64 rate = freq * 1000;
        int ret;

        ret = clk_set_rate(priv->clk, rate);
-       if (!ret && (clk_get_rate(priv->clk) != rate))
-               ret = -EIO;
+       if (!ret) {
I would do:

if (ret)
        return ret;

arch_set_freq_scale(policy->related_cpus, freq, policy->cpuinfo.max_freq);

if (clk_get_rate(priv->clk) != rate)
        return -EIO;

return 0;

That's somewhat easier to follow for me.
+               if (clk_get_rate(priv->clk) != rate)
+                       ret = -EIO;
+
+               arch_set_freq_scale(policy->related_cpus, freq,
+                                   policy->cpuinfo.max_freq);
+       }

        return ret;
 }
--
I also am not sure why you want to call arch_set_freq_scale() even if
the new clock rate didn't stick.
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help