v4.19.13 snapshot.
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
new file mode 100644
index 0000000..e7cb0c6
--- /dev/null
+++ b/drivers/base/arch_topology.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Arch specific cpu topology information
+ *
+ * Copyright (C) 2016, ARM Ltd.
+ * Written by: Juri Lelli, ARM Ltd.
+ */
+
+#include <linux/acpi.h>
+#include <linux/arch_topology.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sched/topology.h>
+
+DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
+
+void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
+ unsigned long max_freq)
+{
+ unsigned long scale;
+ int i;
+
+ scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
+
+ for_each_cpu(i, cpus)
+ per_cpu(freq_scale, i) = scale;
+}
+
+static DEFINE_MUTEX(cpu_scale_mutex);
+DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
+
+void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
+{
+ per_cpu(cpu_scale, cpu) = capacity;
+}
+
+static ssize_t cpu_capacity_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+
+ return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id));
+}
+
+static ssize_t cpu_capacity_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ int this_cpu = cpu->dev.id;
+ int i;
+ unsigned long new_capacity;
+ ssize_t ret;
+
+ if (!count)
+ return 0;
+
+ ret = kstrtoul(buf, 0, &new_capacity);
+ if (ret)
+ return ret;
+ if (new_capacity > SCHED_CAPACITY_SCALE)
+ return -EINVAL;
+
+ mutex_lock(&cpu_scale_mutex);
+ for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
+ topology_set_cpu_scale(i, new_capacity);
+ mutex_unlock(&cpu_scale_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(cpu_capacity);
+
+static int register_cpu_capacity_sysctl(void)
+{
+ int i;
+ struct device *cpu;
+
+ for_each_possible_cpu(i) {
+ cpu = get_cpu_device(i);
+ if (!cpu) {
+ pr_err("%s: too early to get CPU%d device!\n",
+ __func__, i);
+ continue;
+ }
+ device_create_file(cpu, &dev_attr_cpu_capacity);
+ }
+
+ return 0;
+}
+subsys_initcall(register_cpu_capacity_sysctl);
+
+static u32 capacity_scale;
+static u32 *raw_capacity;
+
+static int free_raw_capacity(void)
+{
+ kfree(raw_capacity);
+ raw_capacity = NULL;
+
+ return 0;
+}
+
+void topology_normalize_cpu_scale(void)
+{
+ u64 capacity;
+ int cpu;
+
+ if (!raw_capacity)
+ return;
+
+ pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
+ mutex_lock(&cpu_scale_mutex);
+ for_each_possible_cpu(cpu) {
+ pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
+ cpu, raw_capacity[cpu]);
+ capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
+ / capacity_scale;
+ topology_set_cpu_scale(cpu, capacity);
+ pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
+ cpu, topology_get_cpu_scale(NULL, cpu));
+ }
+ mutex_unlock(&cpu_scale_mutex);
+}
+
+bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
+{
+ static bool cap_parsing_failed;
+ int ret;
+ u32 cpu_capacity;
+
+ if (cap_parsing_failed)
+ return false;
+
+ ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
+ &cpu_capacity);
+ if (!ret) {
+ if (!raw_capacity) {
+ raw_capacity = kcalloc(num_possible_cpus(),
+ sizeof(*raw_capacity),
+ GFP_KERNEL);
+ if (!raw_capacity) {
+ pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
+ cap_parsing_failed = true;
+ return false;
+ }
+ }
+ capacity_scale = max(cpu_capacity, capacity_scale);
+ raw_capacity[cpu] = cpu_capacity;
+ pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
+ cpu_node, raw_capacity[cpu]);
+ } else {
+ if (raw_capacity) {
+ pr_err("cpu_capacity: missing %pOF raw capacity\n",
+ cpu_node);
+ pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
+ }
+ cap_parsing_failed = true;
+ free_raw_capacity();
+ }
+
+ return !ret;
+}
+
+#ifdef CONFIG_CPU_FREQ
+static cpumask_var_t cpus_to_visit;
+static void parsing_done_workfn(struct work_struct *work);
+static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
+
+static int
+init_cpu_capacity_callback(struct notifier_block *nb,
+ unsigned long val,
+ void *data)
+{
+ struct cpufreq_policy *policy = data;
+ int cpu;
+
+ if (!raw_capacity)
+ return 0;
+
+ if (val != CPUFREQ_NOTIFY)
+ return 0;
+
+ pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
+ cpumask_pr_args(policy->related_cpus),
+ cpumask_pr_args(cpus_to_visit));
+
+ cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
+
+ for_each_cpu(cpu, policy->related_cpus) {
+ raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
+ policy->cpuinfo.max_freq / 1000UL;
+ capacity_scale = max(raw_capacity[cpu], capacity_scale);
+ }
+
+ if (cpumask_empty(cpus_to_visit)) {
+ topology_normalize_cpu_scale();
+ free_raw_capacity();
+ pr_debug("cpu_capacity: parsing done\n");
+ schedule_work(&parsing_done_work);
+ }
+
+ return 0;
+}
+
+static struct notifier_block init_cpu_capacity_notifier = {
+ .notifier_call = init_cpu_capacity_callback,
+};
+
+static int __init register_cpufreq_notifier(void)
+{
+ int ret;
+
+ /*
+ * on ACPI-based systems we need to use the default cpu capacity
+ * until we have the necessary code to parse the cpu capacity, so
+ * skip registering cpufreq notifier.
+ */
+ if (!acpi_disabled || !raw_capacity)
+ return -EINVAL;
+
+ if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
+ pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
+ return -ENOMEM;
+ }
+
+ cpumask_copy(cpus_to_visit, cpu_possible_mask);
+
+ ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
+ CPUFREQ_POLICY_NOTIFIER);
+
+ if (ret)
+ free_cpumask_var(cpus_to_visit);
+
+ return ret;
+}
+core_initcall(register_cpufreq_notifier);
+
+static void parsing_done_workfn(struct work_struct *work)
+{
+ cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
+ CPUFREQ_POLICY_NOTIFIER);
+ free_cpumask_var(cpus_to_visit);
+}
+
+#else
+core_initcall(free_raw_capacity);
+#endif