Re: [PATCH V3 4/4] cpufreq: CPPC: Add support for frequency invariance

Hey,

On Monday 21 Jun 2021 at 14:49:37 (+0530), Viresh Kumar wrote:

The Frequency Invariance Engine (FIE) is providing a frequency scaling
correction factor that helps achieve more accurate load-tracking.

[..]

+static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
+{
+	struct cppc_freq_invariance *cppc_fi;
+	int cpu;
+
+	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
+		return;
+
+	/* policy->cpus will be empty here, use related_cpus instead */
+	topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, policy->related_cpus);
+
+	for_each_cpu(cpu, policy->related_cpus) {
+		cppc_fi = &per_cpu(cppc_freq_inv, cpu);

Do you think it might be worth having here something like:

		if (!cppc_fi->cpu_data)
			continue;

This would be to protect against cases where the platform does not boot
with all CPUs or the module is loaded after some have already been
offlined. Unlikely, but..

+		irq_work_sync(&cppc_fi->irq_work);
+		kthread_cancel_work_sync(&cppc_fi->work);
+	}
+}

The rest of the code is almost the same as the original, so that is all
from me :).

Thanks,
Ionela.