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![Chanwoo Choi](/assets/img/avatar_default.png)
Prior to that, the devfreq device uses the governor name when adding the itself. In order to prevent the mistake used the wrong governor name, this patch defines the governor name as a constant and then uses them instead of using the string directly. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: linux-samsung-soc@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org
167 lines
3.6 KiB
C
167 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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