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@@ -0,0 +1,242 @@
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+/*
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+ * Arch specific cpu topology information
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+ *
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+ * Copyright (C) 2016, ARM Ltd.
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+ * Written by: Juri Lelli, ARM Ltd.
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+ *
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+ * This file is subject to the terms and conditions of the GNU General Public
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+ * License. See the file "COPYING" in the main directory of this archive
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+ * for more details.
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+ *
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+ * Released under the GPLv2 only.
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+ * SPDX-License-Identifier: GPL-2.0
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+ */
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+
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+#include <linux/acpi.h>
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+#include <linux/cpu.h>
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+#include <linux/cpufreq.h>
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+#include <linux/device.h>
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+#include <linux/of.h>
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+#include <linux/slab.h>
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+#include <linux/string.h>
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+#include <linux/sched/topology.h>
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+
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+static DEFINE_MUTEX(cpu_scale_mutex);
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+static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
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+
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+unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
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+{
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+ return per_cpu(cpu_scale, cpu);
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+}
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+
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+void set_capacity_scale(unsigned int cpu, unsigned long capacity)
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+{
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+ per_cpu(cpu_scale, cpu) = capacity;
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+}
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+
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+static ssize_t cpu_capacity_show(struct device *dev,
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+ struct device_attribute *attr,
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+ char *buf)
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+{
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+ struct cpu *cpu = container_of(dev, struct cpu, dev);
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+
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+ return sprintf(buf, "%lu\n",
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+ arch_scale_cpu_capacity(NULL, cpu->dev.id));
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+}
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+
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+static ssize_t cpu_capacity_store(struct device *dev,
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+ struct device_attribute *attr,
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+ const char *buf,
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+ size_t count)
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+{
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+ struct cpu *cpu = container_of(dev, struct cpu, dev);
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+ int this_cpu = cpu->dev.id;
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+ int i;
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+ unsigned long new_capacity;
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+ ssize_t ret;
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+
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+ if (!count)
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+ return 0;
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+
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+ ret = kstrtoul(buf, 0, &new_capacity);
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+ if (ret)
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+ return ret;
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+ if (new_capacity > SCHED_CAPACITY_SCALE)
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+ return -EINVAL;
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+
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+ mutex_lock(&cpu_scale_mutex);
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+ for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
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+ set_capacity_scale(i, new_capacity);
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+ mutex_unlock(&cpu_scale_mutex);
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+
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+ return count;
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+}
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+
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+static DEVICE_ATTR_RW(cpu_capacity);
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+
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+static int register_cpu_capacity_sysctl(void)
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+{
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+ int i;
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+ struct device *cpu;
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+
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+ for_each_possible_cpu(i) {
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+ cpu = get_cpu_device(i);
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+ if (!cpu) {
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+ pr_err("%s: too early to get CPU%d device!\n",
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+ __func__, i);
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+ continue;
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+ }
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+ device_create_file(cpu, &dev_attr_cpu_capacity);
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+ }
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+
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+ return 0;
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+}
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+subsys_initcall(register_cpu_capacity_sysctl);
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+
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+static u32 capacity_scale;
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+static u32 *raw_capacity;
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+bool cap_parsing_failed;
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+
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+void normalize_cpu_capacity(void)
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+{
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+ u64 capacity;
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+ int cpu;
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+
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+ if (!raw_capacity || cap_parsing_failed)
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+ return;
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+
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+ pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
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+ mutex_lock(&cpu_scale_mutex);
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+ for_each_possible_cpu(cpu) {
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+ pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
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+ cpu, raw_capacity[cpu]);
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+ capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
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+ / capacity_scale;
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+ set_capacity_scale(cpu, capacity);
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+ pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
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+ cpu, arch_scale_cpu_capacity(NULL, cpu));
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+ }
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+ mutex_unlock(&cpu_scale_mutex);
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+}
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+
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+int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
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+{
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+ int ret = 1;
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+ u32 cpu_capacity;
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+
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+ if (cap_parsing_failed)
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+ return !ret;
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+
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+ ret = of_property_read_u32(cpu_node,
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+ "capacity-dmips-mhz",
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+ &cpu_capacity);
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+ if (!ret) {
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+ if (!raw_capacity) {
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+ raw_capacity = kcalloc(num_possible_cpus(),
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+ sizeof(*raw_capacity),
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+ GFP_KERNEL);
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+ if (!raw_capacity) {
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+ pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
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+ cap_parsing_failed = true;
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+ return 0;
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+ }
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+ }
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+ capacity_scale = max(cpu_capacity, capacity_scale);
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+ raw_capacity[cpu] = cpu_capacity;
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+ pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
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+ cpu_node->full_name, raw_capacity[cpu]);
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+ } else {
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+ if (raw_capacity) {
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+ pr_err("cpu_capacity: missing %s raw capacity\n",
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+ cpu_node->full_name);
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+ pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
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+ }
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+ cap_parsing_failed = true;
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+ kfree(raw_capacity);
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+ }
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+
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+ return !ret;
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+}
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+
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+#ifdef CONFIG_CPU_FREQ
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+static cpumask_var_t cpus_to_visit;
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+static bool cap_parsing_done;
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+static void parsing_done_workfn(struct work_struct *work);
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+static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
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+
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+static int
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+init_cpu_capacity_callback(struct notifier_block *nb,
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+ unsigned long val,
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+ void *data)
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+{
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+ struct cpufreq_policy *policy = data;
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+ int cpu;
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+
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+ if (cap_parsing_failed || cap_parsing_done)
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+ return 0;
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+
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+ switch (val) {
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+ case CPUFREQ_NOTIFY:
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+ pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
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+ cpumask_pr_args(policy->related_cpus),
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+ cpumask_pr_args(cpus_to_visit));
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+ cpumask_andnot(cpus_to_visit,
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+ cpus_to_visit,
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+ policy->related_cpus);
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+ for_each_cpu(cpu, policy->related_cpus) {
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+ raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
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+ policy->cpuinfo.max_freq / 1000UL;
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+ capacity_scale = max(raw_capacity[cpu], capacity_scale);
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+ }
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+ if (cpumask_empty(cpus_to_visit)) {
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+ normalize_cpu_capacity();
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+ kfree(raw_capacity);
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+ pr_debug("cpu_capacity: parsing done\n");
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+ cap_parsing_done = true;
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+ schedule_work(&parsing_done_work);
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+ }
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+ }
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+ return 0;
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+}
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+
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+static struct notifier_block init_cpu_capacity_notifier = {
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+ .notifier_call = init_cpu_capacity_callback,
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+};
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+
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+static int __init register_cpufreq_notifier(void)
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+{
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+ /*
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+ * on ACPI-based systems we need to use the default cpu capacity
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+ * until we have the necessary code to parse the cpu capacity, so
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+ * skip registering cpufreq notifier.
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+ */
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+ if (!acpi_disabled || cap_parsing_failed)
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+ return -EINVAL;
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+
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+ if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
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+ pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
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+ return -ENOMEM;
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+ }
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+
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+ cpumask_copy(cpus_to_visit, cpu_possible_mask);
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+
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+ return cpufreq_register_notifier(&init_cpu_capacity_notifier,
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+ CPUFREQ_POLICY_NOTIFIER);
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+}
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+core_initcall(register_cpufreq_notifier);
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+
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+static void parsing_done_workfn(struct work_struct *work)
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+{
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+ cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
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+ CPUFREQ_POLICY_NOTIFIER);
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+}
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+
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+#else
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+static int __init free_raw_capacity(void)
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+{
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+ kfree(raw_capacity);
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+
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+ return 0;
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+}
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+core_initcall(free_raw_capacity);
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+#endif
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Juri Lelli