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1// SPDX-License-Identifier: GPL-2.0-only
2
3/*
4 * linux/drivers/cpufreq/cpufreq_userspace.c
5 *
6 * Copyright (C) 2001 Russell King
7 * (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/cpufreq.h>
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/slab.h>
17
18struct userspace_policy {
19 unsigned int is_managed;
20 unsigned int setspeed;
21 struct mutex mutex;
22};
23
24/**
25 * cpufreq_set - set the CPU frequency
26 * @policy: pointer to policy struct where freq is being set
27 * @freq: target frequency in kHz
28 *
29 * Sets the CPU frequency to freq.
30 */
31static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
32{
33 int ret = -EINVAL;
34 struct userspace_policy *userspace = policy->governor_data;
35
36 pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
37
38 mutex_lock(&userspace->mutex);
39 if (!userspace->is_managed)
40 goto err;
41
42 userspace->setspeed = freq;
43
44 ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
45 err:
46 mutex_unlock(&userspace->mutex);
47 return ret;
48}
49
50static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
51{
52 return sprintf(buf, "%u\n", policy->cur);
53}
54
55static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
56{
57 struct userspace_policy *userspace;
58
59 userspace = kzalloc(sizeof(*userspace), GFP_KERNEL);
60 if (!userspace)
61 return -ENOMEM;
62
63 mutex_init(&userspace->mutex);
64
65 policy->governor_data = userspace;
66 return 0;
67}
68
69/*
70 * Any routine that writes to the policy struct will hold the "rwsem" of
71 * policy struct that means it is free to free "governor_data" here.
72 */
73static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
74{
75 kfree(policy->governor_data);
76 policy->governor_data = NULL;
77}
78
79static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
80{
81 struct userspace_policy *userspace = policy->governor_data;
82
83 BUG_ON(!policy->cur);
84 pr_debug("started managing cpu %u\n", policy->cpu);
85
86 mutex_lock(&userspace->mutex);
87 userspace->is_managed = 1;
88 userspace->setspeed = policy->cur;
89 mutex_unlock(&userspace->mutex);
90 return 0;
91}
92
93static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
94{
95 struct userspace_policy *userspace = policy->governor_data;
96
97 pr_debug("managing cpu %u stopped\n", policy->cpu);
98
99 mutex_lock(&userspace->mutex);
100 userspace->is_managed = 0;
101 userspace->setspeed = 0;
102 mutex_unlock(&userspace->mutex);
103}
104
105static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
106{
107 struct userspace_policy *userspace = policy->governor_data;
108
109 mutex_lock(&userspace->mutex);
110
111 pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
112 policy->cpu, policy->min, policy->max, policy->cur, userspace->setspeed);
113
114 if (policy->max < userspace->setspeed)
115 __cpufreq_driver_target(policy, policy->max,
116 CPUFREQ_RELATION_H);
117 else if (policy->min > userspace->setspeed)
118 __cpufreq_driver_target(policy, policy->min,
119 CPUFREQ_RELATION_L);
120 else
121 __cpufreq_driver_target(policy, userspace->setspeed,
122 CPUFREQ_RELATION_L);
123
124 mutex_unlock(&userspace->mutex);
125}
126
127static struct cpufreq_governor cpufreq_gov_userspace = {
128 .name = "userspace",
129 .init = cpufreq_userspace_policy_init,
130 .exit = cpufreq_userspace_policy_exit,
131 .start = cpufreq_userspace_policy_start,
132 .stop = cpufreq_userspace_policy_stop,
133 .limits = cpufreq_userspace_policy_limits,
134 .store_setspeed = cpufreq_set,
135 .show_setspeed = show_speed,
136 .owner = THIS_MODULE,
137};
138
139MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
140 "Russell King <rmk@arm.linux.org.uk>");
141MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
142MODULE_LICENSE("GPL");
143
144#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
145struct cpufreq_governor *cpufreq_default_governor(void)
146{
147 return &cpufreq_gov_userspace;
148}
149#endif
150
151cpufreq_governor_init(cpufreq_gov_userspace);
152cpufreq_governor_exit(cpufreq_gov_userspace);
1
2/*
3 * linux/drivers/cpufreq/cpufreq_userspace.c
4 *
5 * Copyright (C) 2001 Russell King
6 * (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/cpufreq.h>
17#include <linux/init.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/slab.h>
21
22static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
23static DEFINE_MUTEX(userspace_mutex);
24
25/**
26 * cpufreq_set - set the CPU frequency
27 * @policy: pointer to policy struct where freq is being set
28 * @freq: target frequency in kHz
29 *
30 * Sets the CPU frequency to freq.
31 */
32static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
33{
34 int ret = -EINVAL;
35 unsigned int *setspeed = policy->governor_data;
36
37 pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
38
39 mutex_lock(&userspace_mutex);
40 if (!per_cpu(cpu_is_managed, policy->cpu))
41 goto err;
42
43 *setspeed = freq;
44
45 ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
46 err:
47 mutex_unlock(&userspace_mutex);
48 return ret;
49}
50
51static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
52{
53 return sprintf(buf, "%u\n", policy->cur);
54}
55
56static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
57{
58 unsigned int *setspeed;
59
60 setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);
61 if (!setspeed)
62 return -ENOMEM;
63
64 policy->governor_data = setspeed;
65 return 0;
66}
67
68static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
69{
70 mutex_lock(&userspace_mutex);
71 kfree(policy->governor_data);
72 policy->governor_data = NULL;
73 mutex_unlock(&userspace_mutex);
74}
75
76static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
77{
78 unsigned int *setspeed = policy->governor_data;
79
80 BUG_ON(!policy->cur);
81 pr_debug("started managing cpu %u\n", policy->cpu);
82
83 mutex_lock(&userspace_mutex);
84 per_cpu(cpu_is_managed, policy->cpu) = 1;
85 *setspeed = policy->cur;
86 mutex_unlock(&userspace_mutex);
87 return 0;
88}
89
90static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
91{
92 unsigned int *setspeed = policy->governor_data;
93
94 pr_debug("managing cpu %u stopped\n", policy->cpu);
95
96 mutex_lock(&userspace_mutex);
97 per_cpu(cpu_is_managed, policy->cpu) = 0;
98 *setspeed = 0;
99 mutex_unlock(&userspace_mutex);
100}
101
102static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
103{
104 unsigned int *setspeed = policy->governor_data;
105
106 mutex_lock(&userspace_mutex);
107
108 pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
109 policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
110
111 if (policy->max < *setspeed)
112 __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
113 else if (policy->min > *setspeed)
114 __cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
115 else
116 __cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
117
118 mutex_unlock(&userspace_mutex);
119}
120
121static struct cpufreq_governor cpufreq_gov_userspace = {
122 .name = "userspace",
123 .init = cpufreq_userspace_policy_init,
124 .exit = cpufreq_userspace_policy_exit,
125 .start = cpufreq_userspace_policy_start,
126 .stop = cpufreq_userspace_policy_stop,
127 .limits = cpufreq_userspace_policy_limits,
128 .store_setspeed = cpufreq_set,
129 .show_setspeed = show_speed,
130 .owner = THIS_MODULE,
131};
132
133static int __init cpufreq_gov_userspace_init(void)
134{
135 return cpufreq_register_governor(&cpufreq_gov_userspace);
136}
137
138static void __exit cpufreq_gov_userspace_exit(void)
139{
140 cpufreq_unregister_governor(&cpufreq_gov_userspace);
141}
142
143MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
144 "Russell King <rmk@arm.linux.org.uk>");
145MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
146MODULE_LICENSE("GPL");
147
148#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
149struct cpufreq_governor *cpufreq_default_governor(void)
150{
151 return &cpufreq_gov_userspace;
152}
153
154fs_initcall(cpufreq_gov_userspace_init);
155#else
156module_init(cpufreq_gov_userspace_init);
157#endif
158module_exit(cpufreq_gov_userspace_exit);