168 lines
3.6 KiB
C
168 lines
3.6 KiB
C
/*
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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 <myungjoo.ham@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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unsigned long adjusted_freq = data->user_frequency;
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if (df->max_freq && adjusted_freq > df->max_freq)
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adjusted_freq = df->max_freq;
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if (df->min_freq && adjusted_freq < df->min_freq)
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adjusted_freq = df->min_freq;
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*freq = adjusted_freq;
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} else {
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*freq = df->previous_freq; /* No user freq specified yet */
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}
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return 0;
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}
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static ssize_t store_freq(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 show_freq(struct device *dev, struct device_attribute *attr,
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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(set_freq, 0644, show_freq, store_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 = "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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