Re: [PATCH V2 9/9] cpufreq: scmi: Use .register_em() callback

On Wednesday 11 Aug 2021 at 15:09:13 (+0100), Lukasz Luba wrote:

On 8/11/21 2:17 PM, Quentin Perret wrote:

quoted

On Wednesday 11 Aug 2021 at 17:28:47 (+0530), Viresh Kumar wrote:

quoted

Set the newly added .register_em() callback to register with the EM
after the cpufreq policy is properly initialized.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
  drivers/cpufreq/scmi-cpufreq.c | 55 ++++++++++++++++++++--------------
  1 file changed, 32 insertions(+), 23 deletions(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index 75f818d04b48..b916c9e22921 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c

@@ -22,7 +22,9 @@
  struct scmi_data {
  	int domain_id;
+	int nr_opp;
  	struct device *cpu_dev;
+	cpumask_var_t opp_shared_cpus;

Can we use policy->related_cpus and friends directly in the callback

Unfortunately not. This tricky setup code was introduced because we may
have a platform with per-CPU policy, so single bit set in
policy->related_cpus, but we want EAS to be still working on set
of CPUs. That's why we construct temporary cpumask and pass it to EM.

Aha, I see this now. Hmm, those platforms better have AMUs then,
otherwise PELT signals will be wonky ...

I was going to suggest using dev_pm_opp_get_sharing_cpus() from the
callback instead, but maybe that's overkill as we'd need to allocate a
temporary cpumask and all. So n/m this patch should be fine as is.

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