Merge tag 'sunxi-clk-for-3.13' of https://github.com/mripard/linux into clk-next...
[linux-2.6-microblaze.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
21 static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
22 static DEFINE_MUTEX(userspace_mutex);
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  */
31 static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
32 {
33         int ret = -EINVAL;
34
35         pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
36
37         mutex_lock(&userspace_mutex);
38         if (!per_cpu(cpu_is_managed, policy->cpu))
39                 goto err;
40
41         ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
42  err:
43         mutex_unlock(&userspace_mutex);
44         return ret;
45 }
46
47 static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
48 {
49         return sprintf(buf, "%u\n", policy->cur);
50 }
51
52 static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
53                                    unsigned int event)
54 {
55         unsigned int cpu = policy->cpu;
56         int rc = 0;
57
58         switch (event) {
59         case CPUFREQ_GOV_START:
60                 BUG_ON(!policy->cur);
61                 pr_debug("started managing cpu %u\n", cpu);
62
63                 mutex_lock(&userspace_mutex);
64                 per_cpu(cpu_is_managed, cpu) = 1;
65                 mutex_unlock(&userspace_mutex);
66                 break;
67         case CPUFREQ_GOV_STOP:
68                 pr_debug("managing cpu %u stopped\n", cpu);
69
70                 mutex_lock(&userspace_mutex);
71                 per_cpu(cpu_is_managed, cpu) = 0;
72                 mutex_unlock(&userspace_mutex);
73                 break;
74         case CPUFREQ_GOV_LIMITS:
75                 mutex_lock(&userspace_mutex);
76                 pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz\n",
77                         cpu, policy->min, policy->max,
78                         policy->cur);
79
80                 if (policy->max < policy->cur)
81                         __cpufreq_driver_target(policy, policy->max,
82                                                 CPUFREQ_RELATION_H);
83                 else if (policy->min > policy->cur)
84                         __cpufreq_driver_target(policy, policy->min,
85                                                 CPUFREQ_RELATION_L);
86                 mutex_unlock(&userspace_mutex);
87                 break;
88         }
89         return rc;
90 }
91
92 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
93 static
94 #endif
95 struct cpufreq_governor cpufreq_gov_userspace = {
96         .name           = "userspace",
97         .governor       = cpufreq_governor_userspace,
98         .store_setspeed = cpufreq_set,
99         .show_setspeed  = show_speed,
100         .owner          = THIS_MODULE,
101 };
102
103 static int __init cpufreq_gov_userspace_init(void)
104 {
105         return cpufreq_register_governor(&cpufreq_gov_userspace);
106 }
107
108 static void __exit cpufreq_gov_userspace_exit(void)
109 {
110         cpufreq_unregister_governor(&cpufreq_gov_userspace);
111 }
112
113 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
114                 "Russell King <rmk@arm.linux.org.uk>");
115 MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
116 MODULE_LICENSE("GPL");
117
118 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
119 fs_initcall(cpufreq_gov_userspace_init);
120 #else
121 module_init(cpufreq_gov_userspace_init);
122 #endif
123 module_exit(cpufreq_gov_userspace_exit);