[mirror_ubuntu-jammy-kernel.git] / drivers / base / arch_topology.c

/*
 * Arch specific cpu topology information
 *
 * Copyright (C) 2016, ARM Ltd.
 * Written by: Juri Lelli, ARM Ltd.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Released under the GPLv2 only.
 * SPDX-License-Identifier: GPL-2.0
 */

#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>

static DEFINE_MUTEX(cpu_scale_mutex);
static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;

unsigned long topology_get_cpu_scale(struct sched_domain *sd, int cpu)
{
	return per_cpu(cpu_scale, cpu);
}

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 __init 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)
{
	/*
	 * 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);

	return cpufreq_register_notifier(&init_cpu_capacity_notifier,
					 CPUFREQ_POLICY_NOTIFIER);
}
core_initcall(register_cpufreq_notifier);

static void parsing_done_workfn(struct work_struct *work)
{
	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
					 CPUFREQ_POLICY_NOTIFIER);
}

#else
core_initcall(free_raw_capacity);
#endif
Commit	Line	Data
2ef7a295 JL	1	/*
	2	* Arch specific cpu topology information
	3	*
	4	* Copyright (C) 2016, ARM Ltd.
	5	* Written by: Juri Lelli, ARM Ltd.
	6	*
	7	* This file is subject to the terms and conditions of the GNU General Public
	8	* License. See the file "COPYING" in the main directory of this archive
	9	* for more details.
	10	*
	11	* Released under the GPLv2 only.
	12	* SPDX-License-Identifier: GPL-2.0
	13	*/
	14
	15	#include <linux/acpi.h>
615ffd63	16	#include <linux/arch_topology.h>
2ef7a295 JL	17	#include <linux/cpu.h>
	18	#include <linux/cpufreq.h>
	19	#include <linux/device.h>
	20	#include <linux/of.h>
	21	#include <linux/slab.h>
	22	#include <linux/string.h>
	23	#include <linux/sched/topology.h>
	24
	25	static DEFINE_MUTEX(cpu_scale_mutex);
	26	static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
	27
4ca4f26a	28	unsigned long topology_get_cpu_scale(struct sched_domain *sd, int cpu)
2ef7a295 JL	29	{
	30	return per_cpu(cpu_scale, cpu);
	31	}
	32
4ca4f26a	33	void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
2ef7a295 JL	34	{
	35	per_cpu(cpu_scale, cpu) = capacity;
	36	}
	37
	38	static ssize_t cpu_capacity_show(struct device *dev,
	39	struct device_attribute *attr,
	40	char *buf)
	41	{
	42	struct cpu *cpu = container_of(dev, struct cpu, dev);
	43
3eeba1a2	44	return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id));
2ef7a295 JL	45	}
	46
	47	static ssize_t cpu_capacity_store(struct device *dev,
	48	struct device_attribute *attr,
	49	const char *buf,
	50	size_t count)
	51	{
	52	struct cpu *cpu = container_of(dev, struct cpu, dev);
	53	int this_cpu = cpu->dev.id;
	54	int i;
	55	unsigned long new_capacity;
	56	ssize_t ret;
	57
	58	if (!count)
	59	return 0;
	60
	61	ret = kstrtoul(buf, 0, &new_capacity);
	62	if (ret)
	63	return ret;
	64	if (new_capacity > SCHED_CAPACITY_SCALE)
	65	return -EINVAL;
	66
	67	mutex_lock(&cpu_scale_mutex);
	68	for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
4ca4f26a	69	topology_set_cpu_scale(i, new_capacity);
2ef7a295 JL	70	mutex_unlock(&cpu_scale_mutex);
	71
	72	return count;
	73	}
	74
	75	static DEVICE_ATTR_RW(cpu_capacity);
	76
	77	static int register_cpu_capacity_sysctl(void)
	78	{
	79	int i;
	80	struct device *cpu;
	81
	82	for_each_possible_cpu(i) {
	83	cpu = get_cpu_device(i);
	84	if (!cpu) {
	85	pr_err("%s: too early to get CPU%d device!\n",
	86	__func__, i);
	87	continue;
	88	}
	89	device_create_file(cpu, &dev_attr_cpu_capacity);
	90	}
	91
	92	return 0;
	93	}
	94	subsys_initcall(register_cpu_capacity_sysctl);
	95
	96	static u32 capacity_scale;
	97	static u32 *raw_capacity;
62de1161 VK	98
	99	static int __init free_raw_capacity(void)
	100	{
	101	kfree(raw_capacity);
	102	raw_capacity = NULL;
	103
	104	return 0;
	105	}
2ef7a295	106
4ca4f26a	107	void topology_normalize_cpu_scale(void)
2ef7a295 JL	108	{
	109	u64 capacity;
	110	int cpu;
	111
62de1161	112	if (!raw_capacity)
2ef7a295 JL	113	return;
	114
	115	pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
	116	mutex_lock(&cpu_scale_mutex);
	117	for_each_possible_cpu(cpu) {
	118	pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
	119	cpu, raw_capacity[cpu]);
	120	capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
	121	/ capacity_scale;
4ca4f26a	122	topology_set_cpu_scale(cpu, capacity);
2ef7a295	123	pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
4ca4f26a	124	cpu, topology_get_cpu_scale(NULL, cpu));
2ef7a295 JL	125	}
	126	mutex_unlock(&cpu_scale_mutex);
	127	}
	128
805df296	129	bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
2ef7a295	130	{
62de1161	131	static bool cap_parsing_failed;
805df296	132	int ret;
2ef7a295 JL	133	u32 cpu_capacity;
	134
	135	if (cap_parsing_failed)
805df296	136	return false;
2ef7a295	137
3eeba1a2	138	ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
2ef7a295 JL	139	&cpu_capacity);
	140	if (!ret) {
	141	if (!raw_capacity) {
	142	raw_capacity = kcalloc(num_possible_cpus(),
	143	sizeof(*raw_capacity),
	144	GFP_KERNEL);
	145	if (!raw_capacity) {
	146	pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
	147	cap_parsing_failed = true;
805df296	148	return false;
2ef7a295 JL	149	}
	150	}
	151	capacity_scale = max(cpu_capacity, capacity_scale);
	152	raw_capacity[cpu] = cpu_capacity;
6ef2541f RH	153	pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
6ef2541f RH	154	cpu_node, raw_capacity[cpu]);
2ef7a295 JL	155	} else {
2ef7a295 JL	156	if (raw_capacity) {
6ef2541f RH	157	pr_err("cpu_capacity: missing %pOF raw capacity\n",
6ef2541f RH	158	cpu_node);
2ef7a295 JL	159	pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
	160	}
	161	cap_parsing_failed = true;
62de1161	162	free_raw_capacity();
2ef7a295 JL	163	}
	164
	165	return !ret;
	166	}
	167
	168	#ifdef CONFIG_CPU_FREQ
	169	static cpumask_var_t cpus_to_visit;
2ef7a295 JL	170	static void parsing_done_workfn(struct work_struct *work);
	171	static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
	172
	173	static int
	174	init_cpu_capacity_callback(struct notifier_block *nb,
	175	unsigned long val,
	176	void *data)
	177	{
	178	struct cpufreq_policy *policy = data;
	179	int cpu;
	180
d8bcf4db	181	if (!raw_capacity)
2ef7a295 JL	182	return 0;
2ef7a295 JL	183
93a57081 VK	184	if (val != CPUFREQ_NOTIFY)
	185	return 0;
	186
	187	pr_debug("cpu_capacity: init cpu capacity for CPUs [%pbl] (to_visit=%pbl)\n",
	188	cpumask_pr_args(policy->related_cpus),
	189	cpumask_pr_args(cpus_to_visit));
	190
	191	cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
	192
	193	for_each_cpu(cpu, policy->related_cpus) {
	194	raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
	195	policy->cpuinfo.max_freq / 1000UL;
	196	capacity_scale = max(raw_capacity[cpu], capacity_scale);
2ef7a295	197	}
93a57081 VK	198
	199	if (cpumask_empty(cpus_to_visit)) {
	200	topology_normalize_cpu_scale();
62de1161	201	free_raw_capacity();
93a57081	202	pr_debug("cpu_capacity: parsing done\n");
93a57081 VK	203	schedule_work(&parsing_done_work);
	204	}
	205
2ef7a295 JL	206	return 0;
	207	}
	208
	209	static struct notifier_block init_cpu_capacity_notifier = {
	210	.notifier_call = init_cpu_capacity_callback,
	211	};
	212
	213	static int __init register_cpufreq_notifier(void)
	214	{
	215	/*
	216	* on ACPI-based systems we need to use the default cpu capacity
	217	* until we have the necessary code to parse the cpu capacity, so
	218	* skip registering cpufreq notifier.
	219	*/
c105aa31	220	if (!acpi_disabled \|\| !raw_capacity)
2ef7a295 JL	221	return -EINVAL;
	222
	223	if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
	224	pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
	225	return -ENOMEM;
	226	}
	227
	228	cpumask_copy(cpus_to_visit, cpu_possible_mask);
	229
	230	return cpufreq_register_notifier(&init_cpu_capacity_notifier,
	231	CPUFREQ_POLICY_NOTIFIER);
	232	}
	233	core_initcall(register_cpufreq_notifier);
	234
	235	static void parsing_done_workfn(struct work_struct *work)
	236	{
	237	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
	238	CPUFREQ_POLICY_NOTIFIER);
	239	}
	240
	241	#else
2ef7a295 JL	242	core_initcall(free_raw_capacity);
2ef7a295 JL	243	#endif