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> | |
21 | #include <linux/types.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/sysfs.h> | |
3fc54d37 | 24 | #include <linux/mutex.h> |
1da177e4 LT |
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]; | |
1da177e4 | 37 | |
3fc54d37 | 38 | static DEFINE_MUTEX (userspace_mutex); |
1da177e4 LT |
39 | |
40 | #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg) | |
41 | ||
42 | /* keep track of frequency transitions */ | |
32ee8c3e | 43 | static int |
1da177e4 LT |
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 | ||
32ee8c3e | 60 | /** |
1da177e4 LT |
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 | */ | |
c0672860 | 67 | static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy) |
1da177e4 LT |
68 | { |
69 | int ret = -EINVAL; | |
70 | ||
c0672860 | 71 | dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); |
1da177e4 | 72 | |
3fc54d37 | 73 | mutex_lock(&userspace_mutex); |
c0672860 | 74 | if (!cpu_is_managed[policy->cpu]) |
1da177e4 LT |
75 | goto err; |
76 | ||
c0672860 | 77 | cpu_set_freq[policy->cpu] = freq; |
1da177e4 | 78 | |
c0672860 TR |
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]; | |
1da177e4 LT |
83 | |
84 | /* | |
85 | * We're safe from concurrent calls to ->target() here | |
3fc54d37 | 86 | * as we hold the userspace_mutex lock. If we were calling |
1da177e4 | 87 | * cpufreq_driver_target, a deadlock situation might occur: |
3fc54d37 | 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) | |
1da177e4 | 90 | */ |
c0672860 | 91 | ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L); |
1da177e4 LT |
92 | |
93 | err: | |
3fc54d37 | 94 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
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 | ||
32ee8c3e DJ |
105 | static ssize_t |
106 | store_speed (struct cpufreq_policy *policy, const char *buf, size_t count) | |
1da177e4 LT |
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 | ||
c0672860 | 115 | cpufreq_set(freq, policy); |
1da177e4 LT |
116 | |
117 | return count; | |
118 | } | |
119 | ||
32ee8c3e | 120 | static struct freq_attr freq_attr_scaling_setspeed = |
1da177e4 LT |
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); | |
3fc54d37 | 136 | mutex_lock(&userspace_mutex); |
32ee8c3e | 137 | cpu_is_managed[cpu] = 1; |
1da177e4 LT |
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); | |
1da177e4 | 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]); |
3fc54d37 | 144 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
145 | break; |
146 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 147 | mutex_lock(&userspace_mutex); |
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; | |
152 | sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr); | |
153 | dprintk("managing cpu %u stopped\n", cpu); | |
3fc54d37 | 154 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
155 | break; |
156 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 157 | mutex_lock(&userspace_mutex); |
c0672860 TR |
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]); | |
1da177e4 | 162 | if (policy->max < cpu_set_freq[cpu]) { |
c0672860 TR |
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); | |
1da177e4 | 169 | } |
c0672860 TR |
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; | |
3fc54d37 | 177 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
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); |