| 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 | static struct cpufreq_governor cpufreq_gov_userspace = { |
| 126 | .name = "userspace", |
| 127 | .governor = cpufreq_governor_userspace, |
| 128 | .store_setspeed = cpufreq_set, |
| 129 | .show_setspeed = show_speed, |
| 130 | .owner = THIS_MODULE, |
| 131 | }; |
| 132 | |
| 133 | static int __init cpufreq_gov_userspace_init(void) |
| 134 | { |
| 135 | return cpufreq_register_governor(&cpufreq_gov_userspace); |
| 136 | } |
| 137 | |
| 138 | static void __exit cpufreq_gov_userspace_exit(void) |
| 139 | { |
| 140 | cpufreq_unregister_governor(&cpufreq_gov_userspace); |
| 141 | } |
| 142 | |
| 143 | MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, " |
| 144 | "Russell King <rmk@arm.linux.org.uk>"); |
| 145 | MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'"); |
| 146 | MODULE_LICENSE("GPL"); |
| 147 | |
| 148 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE |
| 149 | struct cpufreq_governor *cpufreq_default_governor(void) |
| 150 | { |
| 151 | return &cpufreq_gov_userspace; |
| 152 | } |
| 153 | |
| 154 | fs_initcall(cpufreq_gov_userspace_init); |
| 155 | #else |
| 156 | module_init(cpufreq_gov_userspace_init); |
| 157 | #endif |
| 158 | module_exit(cpufreq_gov_userspace_exit); |