[linux-2.6-block.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/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 arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
	return per_cpu(cpu_scale, cpu);
}

void set_capacity_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",
			arch_scale_cpu_capacity(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)
		set_capacity_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 bool cap_parsing_failed;

void normalize_cpu_capacity(void)
{
	u64 capacity;
	int cpu;

	if (!raw_capacity || cap_parsing_failed)
		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;
		set_capacity_scale(cpu, capacity);
		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
			cpu, arch_scale_cpu_capacity(NULL, cpu));
	}
	mutex_unlock(&cpu_scale_mutex);
}

int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
{
	int ret = 1;
	u32 cpu_capacity;

	if (cap_parsing_failed)
		return !ret;

	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 0;
			}
		}
		capacity_scale = max(cpu_capacity, capacity_scale);
		raw_capacity[cpu] = cpu_capacity;
		pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
			cpu_node->full_name, raw_capacity[cpu]);
	} else {
		if (raw_capacity) {
			pr_err("cpu_capacity: missing %s raw capacity\n",
				cpu_node->full_name);
			pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
		}
		cap_parsing_failed = true;
		kfree(raw_capacity);
	}

	return !ret;
}

#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static bool cap_parsing_done;
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 (cap_parsing_failed || cap_parsing_done)
		return 0;

	switch (val) {
	case CPUFREQ_NOTIFY:
		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] = arch_scale_cpu_capacity(NULL, cpu) *
					    policy->cpuinfo.max_freq / 1000UL;
			capacity_scale = max(raw_capacity[cpu], capacity_scale);
		}
		if (cpumask_empty(cpus_to_visit)) {
			normalize_cpu_capacity();
			kfree(raw_capacity);
			pr_debug("cpu_capacity: parsing done\n");
			cap_parsing_done = true;
			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
static int __init free_raw_capacity(void)
{
	kfree(raw_capacity);

	return 0;
}
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>
	16	#include <linux/cpu.h>
	17	#include <linux/cpufreq.h>
	18	#include <linux/device.h>
	19	#include <linux/of.h>
	20	#include <linux/slab.h>
	21	#include <linux/string.h>
	22	#include <linux/sched/topology.h>
	23
	24	static DEFINE_MUTEX(cpu_scale_mutex);
	25	static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
	26
	27	unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
	28	{
	29	return per_cpu(cpu_scale, cpu);
	30	}
	31
	32	void set_capacity_scale(unsigned int cpu, unsigned long capacity)
	33	{
	34	per_cpu(cpu_scale, cpu) = capacity;
	35	}
	36
	37	static ssize_t cpu_capacity_show(struct device *dev,
	38	struct device_attribute *attr,
	39	char *buf)
	40	{
	41	struct cpu *cpu = container_of(dev, struct cpu, dev);
	42
	43	return sprintf(buf, "%lu\n",
	44	arch_scale_cpu_capacity(NULL, cpu->dev.id));
	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)
69	set_capacity_scale(i, new_capacity);
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;
c105aa31	98	static bool cap_parsing_failed;
2ef7a295 JL	99
	100	void normalize_cpu_capacity(void)
	101	{
	102	u64 capacity;
	103	int cpu;
	104
	105	if (!raw_capacity \|\| cap_parsing_failed)
	106	return;
	107
	108	pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
	109	mutex_lock(&cpu_scale_mutex);
	110	for_each_possible_cpu(cpu) {
	111	pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
	112	cpu, raw_capacity[cpu]);
	113	capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
	114	/ capacity_scale;
	115	set_capacity_scale(cpu, capacity);
	116	pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
	117	cpu, arch_scale_cpu_capacity(NULL, cpu));
	118	}
	119	mutex_unlock(&cpu_scale_mutex);
	120	}
	121
	122	int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
	123	{
	124	int ret = 1;
	125	u32 cpu_capacity;
	126
	127	if (cap_parsing_failed)
	128	return !ret;
	129
	130	ret = of_property_read_u32(cpu_node,
	131	"capacity-dmips-mhz",
	132	&cpu_capacity);
	133	if (!ret) {
	134	if (!raw_capacity) {
	135	raw_capacity = kcalloc(num_possible_cpus(),
	136	sizeof(*raw_capacity),
	137	GFP_KERNEL);
	138	if (!raw_capacity) {
	139	pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
	140	cap_parsing_failed = true;
	141	return 0;
	142	}
	143	}
	144	capacity_scale = max(cpu_capacity, capacity_scale);
	145	raw_capacity[cpu] = cpu_capacity;
	146	pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
	147	cpu_node->full_name, raw_capacity[cpu]);
	148	} else {
	149	if (raw_capacity) {
	150	pr_err("cpu_capacity: missing %s raw capacity\n",
	151	cpu_node->full_name);
	152	pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
	153	}
	154	cap_parsing_failed = true;
	155	kfree(raw_capacity);
	156	}
	157
	158	return !ret;
	159	}
	160
	161	#ifdef CONFIG_CPU_FREQ
	162	static cpumask_var_t cpus_to_visit;
163	static bool cap_parsing_done;
164	static void parsing_done_workfn(struct work_struct *work);
165	static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
166
167	static int
168	init_cpu_capacity_callback(struct notifier_block *nb,
169	unsigned long val,
170	void *data)
171	{
172	struct cpufreq_policy *policy = data;
173	int cpu;
174
175	if (cap_parsing_failed \|\| cap_parsing_done)
176	return 0;
177
178	switch (val) {
179	case CPUFREQ_NOTIFY:
180	pr_debug("cpu_capacity: init cpu capacity for CPUs [%pbl] (to_visit=%pbl)\n",
181	cpumask_pr_args(policy->related_cpus),
182	cpumask_pr_args(cpus_to_visit));
183	cpumask_andnot(cpus_to_visit,
184	cpus_to_visit,
185	policy->related_cpus);
186	for_each_cpu(cpu, policy->related_cpus) {
187	raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
188	policy->cpuinfo.max_freq / 1000UL;
189	capacity_scale = max(raw_capacity[cpu], capacity_scale);
190	}
191	if (cpumask_empty(cpus_to_visit)) {
192	normalize_cpu_capacity();
193	kfree(raw_capacity);
194	pr_debug("cpu_capacity: parsing done\n");
195	cap_parsing_done = true;
196	schedule_work(&parsing_done_work);
197	}
198	}
199	return 0;
200	}
201
202	static struct notifier_block init_cpu_capacity_notifier = {
203	.notifier_call = init_cpu_capacity_callback,
204	};
205
206	static int __init register_cpufreq_notifier(void)
207	{
208	/*
209	* on ACPI-based systems we need to use the default cpu capacity
210	* until we have the necessary code to parse the cpu capacity, so
211	* skip registering cpufreq notifier.
212	*/
c105aa31	213	if (!acpi_disabled \|\| !raw_capacity)
2ef7a295 JL	214	return -EINVAL;
	215
	216	if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
	217	pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
	218	return -ENOMEM;
	219	}
	220
	221	cpumask_copy(cpus_to_visit, cpu_possible_mask);
	222
	223	return cpufreq_register_notifier(&init_cpu_capacity_notifier,
	224	CPUFREQ_POLICY_NOTIFIER);
	225	}
	226	core_initcall(register_cpufreq_notifier);
	227
	228	static void parsing_done_workfn(struct work_struct *work)
	229	{
	230	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
	231	CPUFREQ_POLICY_NOTIFIER);
	232	}
	233
	234	#else
	235	static int __init free_raw_capacity(void)
	236	{
	237	kfree(raw_capacity);
	238
	239	return 0;
	240	}
	241	core_initcall(free_raw_capacity);
	242	#endif