diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq_userspace.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq_userspace.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c new file mode 100644 index 0000000000..50a4d78465 --- /dev/null +++ b/drivers/cpufreq/cpufreq_userspace.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * linux/drivers/cpufreq/cpufreq_userspace.c + * + * Copyright (C) 2001 Russell King + * (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/cpufreq.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> + +static DEFINE_PER_CPU(unsigned int, cpu_is_managed); +static DEFINE_MUTEX(userspace_mutex); + +/** + * cpufreq_set - set the CPU frequency + * @policy: pointer to policy struct where freq is being set + * @freq: target frequency in kHz + * + * Sets the CPU frequency to freq. + */ +static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) +{ + int ret = -EINVAL; + unsigned int *setspeed = policy->governor_data; + + pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); + + mutex_lock(&userspace_mutex); + if (!per_cpu(cpu_is_managed, policy->cpu)) + goto err; + + *setspeed = freq; + + ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L); + err: + mutex_unlock(&userspace_mutex); + return ret; +} + +static ssize_t show_speed(struct cpufreq_policy *policy, char *buf) +{ + return sprintf(buf, "%u\n", policy->cur); +} + +static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy) +{ + unsigned int *setspeed; + + setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL); + if (!setspeed) + return -ENOMEM; + + policy->governor_data = setspeed; + return 0; +} + +static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy) +{ + mutex_lock(&userspace_mutex); + kfree(policy->governor_data); + policy->governor_data = NULL; + mutex_unlock(&userspace_mutex); +} + +static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy) +{ + unsigned int *setspeed = policy->governor_data; + + BUG_ON(!policy->cur); + pr_debug("started managing cpu %u\n", policy->cpu); + + mutex_lock(&userspace_mutex); + per_cpu(cpu_is_managed, policy->cpu) = 1; + *setspeed = policy->cur; + mutex_unlock(&userspace_mutex); + return 0; +} + +static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy) +{ + unsigned int *setspeed = policy->governor_data; + + pr_debug("managing cpu %u stopped\n", policy->cpu); + + mutex_lock(&userspace_mutex); + per_cpu(cpu_is_managed, policy->cpu) = 0; + *setspeed = 0; + mutex_unlock(&userspace_mutex); +} + +static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy) +{ + unsigned int *setspeed = policy->governor_data; + + mutex_lock(&userspace_mutex); + + pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n", + policy->cpu, policy->min, policy->max, policy->cur, *setspeed); + + if (policy->max < *setspeed) + __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H); + else if (policy->min > *setspeed) + __cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L); + else + __cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L); + + mutex_unlock(&userspace_mutex); +} + +static struct cpufreq_governor cpufreq_gov_userspace = { + .name = "userspace", + .init = cpufreq_userspace_policy_init, + .exit = cpufreq_userspace_policy_exit, + .start = cpufreq_userspace_policy_start, + .stop = cpufreq_userspace_policy_stop, + .limits = cpufreq_userspace_policy_limits, + .store_setspeed = cpufreq_set, + .show_setspeed = show_speed, + .owner = THIS_MODULE, +}; + +MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, " + "Russell King <rmk@arm.linux.org.uk>"); +MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'"); +MODULE_LICENSE("GPL"); + +#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE +struct cpufreq_governor *cpufreq_default_governor(void) +{ + return &cpufreq_gov_userspace; +} +#endif + +cpufreq_governor_init(cpufreq_gov_userspace); +cpufreq_governor_exit(cpufreq_gov_userspace); |