drivers: psci: remove cluster terminology and dependency on physical_package_id

Since the definition of the term "cluster" is not well defined in the
architecture, we should avoid using it. Also the physical package id
is currently mapped to so called "clusters" in ARM/ARM64 platforms which
is already argumentative.

Currently PSCI checker uses the physical package id assuming that CPU
power domains map to "clusters" and the physical package id in the code
as it stands also maps to cluster boundaries. It does that trying to
test "cluster" idle states to its best. However the CPU power domain
often but not always maps directly to the processor topology.

This patch removes the dependency on physical_package_id from the topology
in this PSCI checker. Also it replaces all the occurences of clusters to
cpu_groups which is derived from core_sibling_mask and may not directly
map to physical "cluster".
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/firmware/psci_checker.c

@@ -77,8 +77,8 @@ static int psci_ops_check(void)
 	return 0;
 }
 
-static int find_clusters(const struct cpumask *cpus,
-			 const struct cpumask **clusters)
+static int find_cpu_groups(const struct cpumask *cpus,
+			   const struct cpumask **cpu_groups)
 {
 	unsigned int nb = 0;
 	cpumask_var_t tmp;
@@ -88,11 +88,11 @@ static int find_clusters(const struct cpumask *cpus,
 	cpumask_copy(tmp, cpus);
 
 	while (!cpumask_empty(tmp)) {
-		const struct cpumask *cluster =
+		const struct cpumask *cpu_group =
 			topology_core_cpumask(cpumask_any(tmp));
 
-		clusters[nb++] = cluster;
-		cpumask_andnot(tmp, tmp, cluster);
+		cpu_groups[nb++] = cpu_group;
+		cpumask_andnot(tmp, tmp, cpu_group);
 	}
 
 	free_cpumask_var(tmp);
@@ -170,24 +170,24 @@ static int hotplug_tests(void)
 {
 	int err;
 	cpumask_var_t offlined_cpus;
-	int i, nb_cluster;
-	const struct cpumask **clusters;
+	int i, nb_cpu_group;
+	const struct cpumask **cpu_groups;
 	char *page_buf;
 
 	err = -ENOMEM;
 	if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))
 		return err;
-	/* We may have up to nb_available_cpus clusters. */
-	clusters = kmalloc_array(nb_available_cpus, sizeof(*clusters),
-				 GFP_KERNEL);
-	if (!clusters)
+	/* We may have up to nb_available_cpus cpu_groups. */
+	cpu_groups = kmalloc_array(nb_available_cpus, sizeof(*cpu_groups),
+				   GFP_KERNEL);
+	if (!cpu_groups)
 		goto out_free_cpus;
 	page_buf = (char *)__get_free_page(GFP_KERNEL);
 	if (!page_buf)
-		goto out_free_clusters;
+		goto out_free_cpu_groups;
 
 	err = 0;
-	nb_cluster = find_clusters(cpu_online_mask, clusters);
+	nb_cpu_group = find_cpu_groups(cpu_online_mask, cpu_groups);
 
 	/*
 	 * Of course the last CPU cannot be powered down and cpu_down() should
@@ -197,24 +197,22 @@ static int hotplug_tests(void)
 	err += down_and_up_cpus(cpu_online_mask, offlined_cpus);
 
 	/*
-	 * Take down CPUs by cluster this time. When the last CPU is turned
-	 * off, the cluster itself should shut down.
+	 * Take down CPUs by cpu group this time. When the last CPU is turned
+	 * off, the cpu group itself should shut down.
 	 */
-	for (i = 0; i < nb_cluster; ++i) {
-		int cluster_id =
-			topology_physical_package_id(cpumask_any(clusters[i]));
+	for (i = 0; i < nb_cpu_group; ++i) {
 		ssize_t len = cpumap_print_to_pagebuf(true, page_buf,
-						      clusters[i]);
+						      cpu_groups[i]);
 		/* Remove trailing newline. */
 		page_buf[len - 1] = '\0';
-		pr_info("Trying to turn off and on again cluster %d "
-			"(CPUs %s)\n", cluster_id, page_buf);
-		err += down_and_up_cpus(clusters[i], offlined_cpus);
+		pr_info("Trying to turn off and on again group %d (CPUs %s)\n",
+			i, page_buf);
+		err += down_and_up_cpus(cpu_groups[i], offlined_cpus);
 	}
 
 	free_page((unsigned long)page_buf);
-out_free_clusters:
-	kfree(clusters);
+out_free_cpu_groups:
+	kfree(cpu_groups);
 out_free_cpus:
 	free_cpumask_var(offlined_cpus);
 	return err;