Merge branch 'for-next/cpufreq' into for-next/core

* for-next/cpufreq:
  arm64: topology: Do not warn on missing AMU in cpuhp_topology_online()
  arm64: topology: Handle AMU FIE setup on CPU hotplug
  cpufreq: Add new helper function returning cpufreq policy
  arm64: topology: Skip already covered CPUs when setting freq source

1 files changed, 63 insertions, 3 deletions

diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 5d24dc53799b..3fe1faab0362 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -272,7 +272,7 @@ static void amu_fie_setup(const struct cpumask *cpus)
 
 	cpumask_or(amu_fie_cpus, amu_fie_cpus, cpus);
 
-	topology_set_scale_freq_source(&amu_sfd, amu_fie_cpus);
+	topology_set_scale_freq_source(&amu_sfd, cpus);
 
 	pr_debug("CPUs[%*pbl]: counters will be used for FIE.",
 		 cpumask_pr_args(cpus));
@@ -284,7 +284,7 @@ static int init_amu_fie_callback(struct notifier_block *nb, unsigned long val,
 	struct cpufreq_policy *policy = data;
 
 	if (val == CPUFREQ_CREATE_POLICY)
-		amu_fie_setup(policy->related_cpus);
+		amu_fie_setup(policy->cpus);
 
 	/*
 	 * We don't need to handle CPUFREQ_REMOVE_POLICY event as the AMU
@@ -303,10 +303,70 @@ static struct notifier_block init_amu_fie_notifier = {
 	.notifier_call = init_amu_fie_callback,
 };
 
+static int cpuhp_topology_online(unsigned int cpu)
+{
+	struct cpufreq_policy *policy = cpufreq_cpu_policy(cpu);
+
+	/* Those are cheap checks */
+
+	/*
+	 * Skip this CPU if:
+	 *  - it has no cpufreq policy assigned yet,
+	 *  - no policy exists that spans CPUs with AMU counters, or
+	 *  - it was already handled.
+	 */
+	if (unlikely(!policy) || !cpumask_available(amu_fie_cpus) ||
+	    cpumask_test_cpu(cpu, amu_fie_cpus))
+		return 0;
+
+	/*
+	 * Only proceed if all already-online CPUs in this policy
+	 * support AMU counters.
+	 */
+	if (unlikely(!cpumask_subset(policy->cpus, amu_fie_cpus)))
+		return 0;
+
+	/*
+	 * If the new online CPU cannot pass this check, all the CPUs related to
+	 * the same policy should be clear from amu_fie_cpus mask, otherwise they
+	 * may use different source of the freq scale.
+	 */
+	if (!freq_counters_valid(cpu)) {
+		topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_ARCH,
+						 policy->related_cpus);
+		cpumask_andnot(amu_fie_cpus, amu_fie_cpus, policy->related_cpus);
+		return 0;
+	}
+
+	cpumask_set_cpu(cpu, amu_fie_cpus);
+
+	topology_set_scale_freq_source(&amu_sfd, cpumask_of(cpu));
+
+	pr_debug("CPU[%u]: counter will be used for FIE.", cpu);
+
+	return 0;
+}
+
 static int __init init_amu_fie(void)
 {
-	return cpufreq_register_notifier(&init_amu_fie_notifier,
+	int ret;
+
+	ret = cpufreq_register_notifier(&init_amu_fie_notifier,
 					CPUFREQ_POLICY_NOTIFIER);
+	if (ret)
+		return ret;
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"arm64/topology:online",
+					cpuhp_topology_online,
+					NULL);
+	if (ret < 0) {
+		cpufreq_unregister_notifier(&init_amu_fie_notifier,
+					    CPUFREQ_POLICY_NOTIFIER);
+		return ret;
+	}
+
+	return 0;
 }
 core_initcall(init_amu_fie);