Remove obsolete #include <linux/config.h>
[linux-3.10.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 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/smp.h>
17 #include <linux/init.h>
18 #include <linux/spinlock.h>
19 #include <linux/interrupt.h>
20 #include <linux/cpufreq.h>
21 #include <linux/types.h>
22 #include <linux/fs.h>
23 #include <linux/sysfs.h>
24 #include <linux/mutex.h>
25
26 #include <asm/uaccess.h>
27
28
29 /**
30  * A few values needed by the userspace governor
31  */
32 static unsigned int     cpu_max_freq[NR_CPUS];
33 static unsigned int     cpu_min_freq[NR_CPUS];
34 static unsigned int     cpu_cur_freq[NR_CPUS]; /* current CPU freq */
35 static unsigned int     cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
36 static unsigned int     cpu_is_managed[NR_CPUS];
37
38 static DEFINE_MUTEX     (userspace_mutex);
39
40 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
41
42 /* keep track of frequency transitions */
43 static int
44 userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
45                        void *data)
46 {
47         struct cpufreq_freqs *freq = data;
48
49         dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
50         cpu_cur_freq[freq->cpu] = freq->new;
51
52         return 0;
53 }
54
55 static struct notifier_block userspace_cpufreq_notifier_block = {
56         .notifier_call  = userspace_cpufreq_notifier
57 };
58
59
60 /**
61  * cpufreq_set - set the CPU frequency
62  * @freq: target frequency in kHz
63  * @cpu: CPU for which the frequency is to be set
64  *
65  * Sets the CPU frequency to freq.
66  */
67 static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy)
68 {
69         int ret = -EINVAL;
70
71         dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
72
73         mutex_lock(&userspace_mutex);
74         if (!cpu_is_managed[policy->cpu])
75                 goto err;
76
77         cpu_set_freq[policy->cpu] = freq;
78
79         if (freq < cpu_min_freq[policy->cpu])
80                 freq = cpu_min_freq[policy->cpu];
81         if (freq > cpu_max_freq[policy->cpu])
82                 freq = cpu_max_freq[policy->cpu];
83
84         /*
85          * We're safe from concurrent calls to ->target() here
86          * as we hold the userspace_mutex lock. If we were calling
87          * cpufreq_driver_target, a deadlock situation might occur:
88          * A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock)
89          * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex)
90          */
91         ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
92
93  err:
94         mutex_unlock(&userspace_mutex);
95         return ret;
96 }
97
98
99 /************************** sysfs interface ************************/
100 static ssize_t show_speed (struct cpufreq_policy *policy, char *buf)
101 {
102         return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
103 }
104
105 static ssize_t
106 store_speed (struct cpufreq_policy *policy, const char *buf, size_t count)
107 {
108         unsigned int freq = 0;
109         unsigned int ret;
110
111         ret = sscanf (buf, "%u", &freq);
112         if (ret != 1)
113                 return -EINVAL;
114
115         cpufreq_set(freq, policy);
116
117         return count;
118 }
119
120 static struct freq_attr freq_attr_scaling_setspeed =
121 {
122         .attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
123         .show = show_speed,
124         .store = store_speed,
125 };
126
127 static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
128                                    unsigned int event)
129 {
130         unsigned int cpu = policy->cpu;
131         switch (event) {
132         case CPUFREQ_GOV_START:
133                 if (!cpu_online(cpu))
134                         return -EINVAL;
135                 BUG_ON(!policy->cur);
136                 mutex_lock(&userspace_mutex);
137                 cpu_is_managed[cpu] = 1;
138                 cpu_min_freq[cpu] = policy->min;
139                 cpu_max_freq[cpu] = policy->max;
140                 cpu_cur_freq[cpu] = policy->cur;
141                 cpu_set_freq[cpu] = policy->cur;
142                 sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
143                 dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);
144                 mutex_unlock(&userspace_mutex);
145                 break;
146         case CPUFREQ_GOV_STOP:
147                 mutex_lock(&userspace_mutex);
148                 cpu_is_managed[cpu] = 0;
149                 cpu_min_freq[cpu] = 0;
150                 cpu_max_freq[cpu] = 0;
151                 cpu_set_freq[cpu] = 0;
152                 sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
153                 dprintk("managing cpu %u stopped\n", cpu);
154                 mutex_unlock(&userspace_mutex);
155                 break;
156         case CPUFREQ_GOV_LIMITS:
157                 mutex_lock(&userspace_mutex);
158                 dprintk("limit event for cpu %u: %u - %u kHz,"
159                         "currently %u kHz, last set to %u kHz\n",
160                         cpu, policy->min, policy->max,
161                         cpu_cur_freq[cpu], cpu_set_freq[cpu]);
162                 if (policy->max < cpu_set_freq[cpu]) {
163                         __cpufreq_driver_target(policy, policy->max,
164                                                 CPUFREQ_RELATION_H);
165                 }
166                 else if (policy->min > cpu_set_freq[cpu]) {
167                         __cpufreq_driver_target(policy, policy->min,
168                                                 CPUFREQ_RELATION_L);
169                 }
170                 else {
171                         __cpufreq_driver_target(policy, cpu_set_freq[cpu],
172                                                 CPUFREQ_RELATION_L);
173                 }
174                 cpu_min_freq[cpu] = policy->min;
175                 cpu_max_freq[cpu] = policy->max;
176                 cpu_cur_freq[cpu] = policy->cur;
177                 mutex_unlock(&userspace_mutex);
178                 break;
179         }
180         return 0;
181 }
182
183
184 struct cpufreq_governor cpufreq_gov_userspace = {
185         .name           = "userspace",
186         .governor       = cpufreq_governor_userspace,
187         .owner          = THIS_MODULE,
188 };
189 EXPORT_SYMBOL(cpufreq_gov_userspace);
190
191 static int __init cpufreq_gov_userspace_init(void)
192 {
193         cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
194         return cpufreq_register_governor(&cpufreq_gov_userspace);
195 }
196
197
198 static void __exit cpufreq_gov_userspace_exit(void)
199 {
200         cpufreq_unregister_governor(&cpufreq_gov_userspace);
201         cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
202 }
203
204
205 MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
206 MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
207 MODULE_LICENSE ("GPL");
208
209 fs_initcall(cpufreq_gov_userspace_init);
210 module_exit(cpufreq_gov_userspace_exit);