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12#include <linux/slab.h>
13#include <linux/device.h>
14#include <linux/devfreq.h>
15#include <linux/pm.h>
16#include <linux/mutex.h>
17#include <linux/module.h>
18#include "governor.h"
19
20struct userspace_data {
21 unsigned long user_frequency;
22 bool valid;
23};
24
25static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
26{
27 struct userspace_data *data = df->data;
28
29 if (data->valid) {
30 unsigned long adjusted_freq = data->user_frequency;
31
32 if (df->max_freq && adjusted_freq > df->max_freq)
33 adjusted_freq = df->max_freq;
34
35 if (df->min_freq && adjusted_freq < df->min_freq)
36 adjusted_freq = df->min_freq;
37
38 *freq = adjusted_freq;
39 } else {
40 *freq = df->previous_freq;
41 }
42 return 0;
43}
44
45static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
46 const char *buf, size_t count)
47{
48 struct devfreq *devfreq = to_devfreq(dev);
49 struct userspace_data *data;
50 unsigned long wanted;
51 int err = 0;
52
53
54 mutex_lock(&devfreq->lock);
55 data = devfreq->data;
56
57 sscanf(buf, "%lu", &wanted);
58 data->user_frequency = wanted;
59 data->valid = true;
60 err = update_devfreq(devfreq);
61 if (err == 0)
62 err = count;
63 mutex_unlock(&devfreq->lock);
64 return err;
65}
66
67static ssize_t show_freq(struct device *dev, struct device_attribute *attr,
68 char *buf)
69{
70 struct devfreq *devfreq = to_devfreq(dev);
71 struct userspace_data *data;
72 int err = 0;
73
74 mutex_lock(&devfreq->lock);
75 data = devfreq->data;
76
77 if (data->valid)
78 err = sprintf(buf, "%lu\n", data->user_frequency);
79 else
80 err = sprintf(buf, "undefined\n");
81 mutex_unlock(&devfreq->lock);
82 return err;
83}
84
85static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq);
86static struct attribute *dev_entries[] = {
87 &dev_attr_set_freq.attr,
88 NULL,
89};
90static struct attribute_group dev_attr_group = {
91 .name = "userspace",
92 .attrs = dev_entries,
93};
94
95static int userspace_init(struct devfreq *devfreq)
96{
97 int err = 0;
98 struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
99 GFP_KERNEL);
100
101 if (!data) {
102 err = -ENOMEM;
103 goto out;
104 }
105 data->valid = false;
106 devfreq->data = data;
107
108 err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
109out:
110 return err;
111}
112
113static void userspace_exit(struct devfreq *devfreq)
114{
115 sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
116 kfree(devfreq->data);
117 devfreq->data = NULL;
118}
119
120static int devfreq_userspace_handler(struct devfreq *devfreq,
121 unsigned int event, void *data)
122{
123 int ret = 0;
124
125 switch (event) {
126 case DEVFREQ_GOV_START:
127 ret = userspace_init(devfreq);
128 break;
129 case DEVFREQ_GOV_STOP:
130 userspace_exit(devfreq);
131 break;
132 default:
133 break;
134 }
135
136 return ret;
137}
138
139static struct devfreq_governor devfreq_userspace = {
140 .name = "userspace",
141 .get_target_freq = devfreq_userspace_func,
142 .event_handler = devfreq_userspace_handler,
143};
144
145static int __init devfreq_userspace_init(void)
146{
147 return devfreq_add_governor(&devfreq_userspace);
148}
149subsys_initcall(devfreq_userspace_init);
150
151static void __exit devfreq_userspace_exit(void)
152{
153 int ret;
154
155 ret = devfreq_remove_governor(&devfreq_userspace);
156 if (ret)
157 pr_err("%s: failed remove governor %d\n", __func__, ret);
158
159 return;
160}
161module_exit(devfreq_userspace_exit);
162MODULE_LICENSE("GPL");
163
