GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / cpufreq_userspace.c
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
22 static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
23 static 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  */
32 static 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
51 static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
52 {
53         return sprintf(buf, "%u\n", policy->cur);
54 }
55
56 static 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
68 static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
69                                    unsigned int event)
70 {
71         unsigned int *setspeed = policy->governor_data;
72         unsigned int cpu = policy->cpu;
73         int rc = 0;
74
75         if (event == CPUFREQ_GOV_POLICY_INIT)
76                 return cpufreq_userspace_policy_init(policy);
77
78         if (!setspeed)
79                 return -EINVAL;
80
81         switch (event) {
82         case CPUFREQ_GOV_POLICY_EXIT:
83                 mutex_lock(&userspace_mutex);
84                 policy->governor_data = NULL;
85                 kfree(setspeed);
86                 mutex_unlock(&userspace_mutex);
87                 break;
88         case CPUFREQ_GOV_START:
89                 BUG_ON(!policy->cur);
90                 pr_debug("started managing cpu %u\n", cpu);
91
92                 mutex_lock(&userspace_mutex);
93                 per_cpu(cpu_is_managed, cpu) = 1;
94                 *setspeed = policy->cur;
95                 mutex_unlock(&userspace_mutex);
96                 break;
97         case CPUFREQ_GOV_STOP:
98                 pr_debug("managing cpu %u stopped\n", cpu);
99
100                 mutex_lock(&userspace_mutex);
101                 per_cpu(cpu_is_managed, cpu) = 0;
102                 *setspeed = 0;
103                 mutex_unlock(&userspace_mutex);
104                 break;
105         case CPUFREQ_GOV_LIMITS:
106                 mutex_lock(&userspace_mutex);
107                 pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
108                         cpu, policy->min, policy->max, policy->cur, *setspeed);
109
110                 if (policy->max < *setspeed)
111                         __cpufreq_driver_target(policy, policy->max,
112                                                 CPUFREQ_RELATION_H);
113                 else if (policy->min > *setspeed)
114                         __cpufreq_driver_target(policy, policy->min,
115                                                 CPUFREQ_RELATION_L);
116                 else
117                         __cpufreq_driver_target(policy, *setspeed,
118                                                 CPUFREQ_RELATION_L);
119                 mutex_unlock(&userspace_mutex);
120                 break;
121         }
122         return rc;
123 }
124
125 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
126 static
127 #endif
128 struct cpufreq_governor cpufreq_gov_userspace = {
129         .name           = "userspace",
130         .governor       = cpufreq_governor_userspace,
131         .store_setspeed = cpufreq_set,
132         .show_setspeed  = show_speed,
133         .owner          = THIS_MODULE,
134 };
135
136 static int __init cpufreq_gov_userspace_init(void)
137 {
138         return cpufreq_register_governor(&cpufreq_gov_userspace);
139 }
140
141 static void __exit cpufreq_gov_userspace_exit(void)
142 {
143         cpufreq_unregister_governor(&cpufreq_gov_userspace);
144 }
145
146 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
147                 "Russell King <rmk@arm.linux.org.uk>");
148 MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
149 MODULE_LICENSE("GPL");
150
151 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
152 fs_initcall(cpufreq_gov_userspace_init);
153 #else
154 module_init(cpufreq_gov_userspace_init);
155 #endif
156 module_exit(cpufreq_gov_userspace_exit);