Commit | Line | Data |
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c0672860 | 1 | |
1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
153d7f3f | 21 | #include <linux/cpu.h> |
1da177e4 LT |
22 | #include <linux/types.h> |
23 | #include <linux/fs.h> | |
24 | #include <linux/sysfs.h> | |
3fc54d37 | 25 | #include <linux/mutex.h> |
1da177e4 LT |
26 | |
27 | #include <asm/uaccess.h> | |
28 | ||
29 | ||
30 | /** | |
31 | * A few values needed by the userspace governor | |
32 | */ | |
33 | static unsigned int cpu_max_freq[NR_CPUS]; | |
34 | static unsigned int cpu_min_freq[NR_CPUS]; | |
35 | static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */ | |
36 | static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */ | |
37 | static unsigned int cpu_is_managed[NR_CPUS]; | |
1da177e4 | 38 | |
3fc54d37 | 39 | static DEFINE_MUTEX (userspace_mutex); |
c7f652e0 | 40 | static int cpus_using_userspace_governor; |
1da177e4 LT |
41 | |
42 | #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg) | |
43 | ||
44 | /* keep track of frequency transitions */ | |
32ee8c3e | 45 | static int |
1da177e4 LT |
46 | userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
47 | void *data) | |
48 | { | |
49 | struct cpufreq_freqs *freq = data; | |
50 | ||
c7f652e0 VP |
51 | if (!cpu_is_managed[freq->cpu]) |
52 | return 0; | |
53 | ||
54 | dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", | |
55 | freq->cpu, freq->new); | |
1da177e4 LT |
56 | cpu_cur_freq[freq->cpu] = freq->new; |
57 | ||
58 | return 0; | |
59 | } | |
60 | ||
61 | static struct notifier_block userspace_cpufreq_notifier_block = { | |
62 | .notifier_call = userspace_cpufreq_notifier | |
63 | }; | |
64 | ||
65 | ||
32ee8c3e | 66 | /** |
1da177e4 | 67 | * cpufreq_set - set the CPU frequency |
9e76988e | 68 | * @policy: pointer to policy struct where freq is being set |
1da177e4 | 69 | * @freq: target frequency in kHz |
1da177e4 LT |
70 | * |
71 | * Sets the CPU frequency to freq. | |
72 | */ | |
9e76988e | 73 | static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) |
1da177e4 LT |
74 | { |
75 | int ret = -EINVAL; | |
76 | ||
c0672860 | 77 | dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); |
1da177e4 | 78 | |
3fc54d37 | 79 | mutex_lock(&userspace_mutex); |
c0672860 | 80 | if (!cpu_is_managed[policy->cpu]) |
1da177e4 LT |
81 | goto err; |
82 | ||
c0672860 | 83 | cpu_set_freq[policy->cpu] = freq; |
1da177e4 | 84 | |
c0672860 TR |
85 | if (freq < cpu_min_freq[policy->cpu]) |
86 | freq = cpu_min_freq[policy->cpu]; | |
87 | if (freq > cpu_max_freq[policy->cpu]) | |
88 | freq = cpu_max_freq[policy->cpu]; | |
1da177e4 LT |
89 | |
90 | /* | |
91 | * We're safe from concurrent calls to ->target() here | |
3fc54d37 | 92 | * as we hold the userspace_mutex lock. If we were calling |
1da177e4 | 93 | * cpufreq_driver_target, a deadlock situation might occur: |
3fc54d37 | 94 | * A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock) |
95 | * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex) | |
1da177e4 | 96 | */ |
c0672860 | 97 | ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L); |
1da177e4 LT |
98 | |
99 | err: | |
3fc54d37 | 100 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
101 | return ret; |
102 | } | |
103 | ||
104 | ||
9e76988e | 105 | static ssize_t show_speed(struct cpufreq_policy *policy, char *buf) |
1da177e4 | 106 | { |
9e76988e | 107 | return sprintf(buf, "%u\n", cpu_cur_freq[policy->cpu]); |
1da177e4 LT |
108 | } |
109 | ||
1da177e4 LT |
110 | static int cpufreq_governor_userspace(struct cpufreq_policy *policy, |
111 | unsigned int event) | |
112 | { | |
113 | unsigned int cpu = policy->cpu; | |
914f7c31 JG |
114 | int rc = 0; |
115 | ||
1da177e4 LT |
116 | switch (event) { |
117 | case CPUFREQ_GOV_START: | |
118 | if (!cpu_online(cpu)) | |
119 | return -EINVAL; | |
120 | BUG_ON(!policy->cur); | |
3fc54d37 | 121 | mutex_lock(&userspace_mutex); |
914f7c31 | 122 | |
c7f652e0 VP |
123 | if (cpus_using_userspace_governor == 0) { |
124 | cpufreq_register_notifier( | |
125 | &userspace_cpufreq_notifier_block, | |
126 | CPUFREQ_TRANSITION_NOTIFIER); | |
127 | } | |
128 | cpus_using_userspace_governor++; | |
129 | ||
32ee8c3e | 130 | cpu_is_managed[cpu] = 1; |
1da177e4 LT |
131 | cpu_min_freq[cpu] = policy->min; |
132 | cpu_max_freq[cpu] = policy->max; | |
133 | cpu_cur_freq[cpu] = policy->cur; | |
134 | cpu_set_freq[cpu] = policy->cur; | |
1da177e4 | 135 | 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]); |
9e76988e | 136 | |
3fc54d37 | 137 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
138 | break; |
139 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 140 | mutex_lock(&userspace_mutex); |
c7f652e0 VP |
141 | cpus_using_userspace_governor--; |
142 | if (cpus_using_userspace_governor == 0) { | |
143 | cpufreq_unregister_notifier( | |
144 | &userspace_cpufreq_notifier_block, | |
145 | CPUFREQ_TRANSITION_NOTIFIER); | |
146 | } | |
147 | ||
1da177e4 LT |
148 | cpu_is_managed[cpu] = 0; |
149 | cpu_min_freq[cpu] = 0; | |
150 | cpu_max_freq[cpu] = 0; | |
151 | cpu_set_freq[cpu] = 0; | |
1da177e4 | 152 | dprintk("managing cpu %u stopped\n", cpu); |
3fc54d37 | 153 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
154 | break; |
155 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 156 | mutex_lock(&userspace_mutex); |
c0672860 TR |
157 | dprintk("limit event for cpu %u: %u - %u kHz," |
158 | "currently %u kHz, last set to %u kHz\n", | |
159 | cpu, policy->min, policy->max, | |
160 | cpu_cur_freq[cpu], cpu_set_freq[cpu]); | |
1da177e4 | 161 | if (policy->max < cpu_set_freq[cpu]) { |
c0672860 TR |
162 | __cpufreq_driver_target(policy, policy->max, |
163 | CPUFREQ_RELATION_H); | |
164 | } | |
165 | else if (policy->min > cpu_set_freq[cpu]) { | |
166 | __cpufreq_driver_target(policy, policy->min, | |
167 | CPUFREQ_RELATION_L); | |
1da177e4 | 168 | } |
c0672860 TR |
169 | else { |
170 | __cpufreq_driver_target(policy, cpu_set_freq[cpu], | |
171 | CPUFREQ_RELATION_L); | |
172 | } | |
173 | cpu_min_freq[cpu] = policy->min; | |
174 | cpu_max_freq[cpu] = policy->max; | |
175 | cpu_cur_freq[cpu] = policy->cur; | |
3fc54d37 | 176 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
177 | break; |
178 | } | |
914f7c31 | 179 | return rc; |
1da177e4 LT |
180 | } |
181 | ||
182 | ||
183 | struct cpufreq_governor cpufreq_gov_userspace = { | |
184 | .name = "userspace", | |
185 | .governor = cpufreq_governor_userspace, | |
9e76988e VP |
186 | .store_setspeed = cpufreq_set, |
187 | .show_setspeed = show_speed, | |
1da177e4 LT |
188 | .owner = THIS_MODULE, |
189 | }; | |
190 | EXPORT_SYMBOL(cpufreq_gov_userspace); | |
191 | ||
192 | static int __init cpufreq_gov_userspace_init(void) | |
193 | { | |
1da177e4 LT |
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); | |
1da177e4 LT |
201 | } |
202 | ||
203 | ||
204 | MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>"); | |
205 | MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'"); | |
206 | MODULE_LICENSE ("GPL"); | |
207 | ||
6915719b | 208 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE |
1da177e4 | 209 | fs_initcall(cpufreq_gov_userspace_init); |
6915719b JW |
210 | #else |
211 | module_init(cpufreq_gov_userspace_init); | |
212 | #endif | |
1da177e4 | 213 | module_exit(cpufreq_gov_userspace_exit); |