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156 lines
3.3 KiB
156 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/drivers/devfreq/governor_userspace.c |
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* |
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* Copyright (C) 2011 Samsung Electronics |
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* MyungJoo Ham <[email protected]> |
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*/ |
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#include <linux/slab.h> |
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#include <linux/device.h> |
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#include <linux/devfreq.h> |
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#include <linux/pm.h> |
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#include <linux/mutex.h> |
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#include <linux/module.h> |
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#include "governor.h" |
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struct userspace_data { |
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unsigned long user_frequency; |
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bool valid; |
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}; |
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static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) |
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{ |
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struct userspace_data *data = df->data; |
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if (data->valid) |
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*freq = data->user_frequency; |
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else |
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*freq = df->previous_freq; /* No user freq specified yet */ |
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return 0; |
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} |
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static ssize_t set_freq_store(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct devfreq *devfreq = to_devfreq(dev); |
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struct userspace_data *data; |
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unsigned long wanted; |
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int err = 0; |
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mutex_lock(&devfreq->lock); |
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data = devfreq->data; |
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sscanf(buf, "%lu", &wanted); |
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data->user_frequency = wanted; |
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data->valid = true; |
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err = update_devfreq(devfreq); |
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if (err == 0) |
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err = count; |
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mutex_unlock(&devfreq->lock); |
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return err; |
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} |
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static ssize_t set_freq_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct devfreq *devfreq = to_devfreq(dev); |
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struct userspace_data *data; |
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int err = 0; |
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mutex_lock(&devfreq->lock); |
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data = devfreq->data; |
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if (data->valid) |
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err = sprintf(buf, "%lu\n", data->user_frequency); |
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else |
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err = sprintf(buf, "undefined\n"); |
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mutex_unlock(&devfreq->lock); |
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return err; |
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} |
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static DEVICE_ATTR_RW(set_freq); |
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static struct attribute *dev_entries[] = { |
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&dev_attr_set_freq.attr, |
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NULL, |
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}; |
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static const struct attribute_group dev_attr_group = { |
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.name = DEVFREQ_GOV_USERSPACE, |
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.attrs = dev_entries, |
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}; |
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static int userspace_init(struct devfreq *devfreq) |
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{ |
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int err = 0; |
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struct userspace_data *data = kzalloc(sizeof(struct userspace_data), |
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GFP_KERNEL); |
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if (!data) { |
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err = -ENOMEM; |
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goto out; |
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} |
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data->valid = false; |
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devfreq->data = data; |
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err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); |
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out: |
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return err; |
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} |
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static void userspace_exit(struct devfreq *devfreq) |
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{ |
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/* |
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* Remove the sysfs entry, unless this is being called after |
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* device_del(), which should have done this already via kobject_del(). |
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*/ |
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if (devfreq->dev.kobj.sd) |
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sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); |
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kfree(devfreq->data); |
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devfreq->data = NULL; |
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} |
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static int devfreq_userspace_handler(struct devfreq *devfreq, |
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unsigned int event, void *data) |
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{ |
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int ret = 0; |
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switch (event) { |
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case DEVFREQ_GOV_START: |
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ret = userspace_init(devfreq); |
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break; |
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case DEVFREQ_GOV_STOP: |
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userspace_exit(devfreq); |
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break; |
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default: |
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break; |
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} |
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return ret; |
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} |
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static struct devfreq_governor devfreq_userspace = { |
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.name = DEVFREQ_GOV_USERSPACE, |
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.get_target_freq = devfreq_userspace_func, |
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.event_handler = devfreq_userspace_handler, |
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}; |
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static int __init devfreq_userspace_init(void) |
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{ |
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return devfreq_add_governor(&devfreq_userspace); |
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} |
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subsys_initcall(devfreq_userspace_init); |
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static void __exit devfreq_userspace_exit(void) |
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{ |
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int ret; |
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ret = devfreq_remove_governor(&devfreq_userspace); |
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if (ret) |
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pr_err("%s: failed remove governor %d\n", __func__, ret); |
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return; |
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} |
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module_exit(devfreq_userspace_exit); |
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MODULE_LICENSE("GPL");
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