tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/config.h>
2#include <linux/types.h>
3#include <linux/errno.h>
4#include <linux/kernel.h>
5#include <linux/delay.h>
6#include <linux/slab.h>
7#include <linux/init.h>
8#include <linux/wait.h>
9#include <linux/cpufreq.h>
10
11#include "windfarm.h"
12
13#define VERSION "0.3"
14
15static int clamped;
16static struct wf_control *clamp_control;
17
18static int clamp_notifier_call(struct notifier_block *self,
19 unsigned long event, void *data)
20{
21 struct cpufreq_policy *p = data;
22 unsigned long max_freq;
23
24 if (event != CPUFREQ_ADJUST)
25 return 0;
26
27 max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
28 cpufreq_verify_within_limits(p, 0, max_freq);
29
30 return 0;
31}
32
33static struct notifier_block clamp_notifier = {
34 .notifier_call = clamp_notifier_call,
35};
36
37static int clamp_set(struct wf_control *ct, s32 value)
38{
39 if (value)
40 printk(KERN_INFO "windfarm: Clamping CPU frequency to "
41 "minimum !\n");
42 else
43 printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
44 clamped = value;
45 cpufreq_update_policy(0);
46 return 0;
47}
48
49static int clamp_get(struct wf_control *ct, s32 *value)
50{
51 *value = clamped;
52 return 0;
53}
54
55static s32 clamp_min(struct wf_control *ct)
56{
57 return 0;
58}
59
60static s32 clamp_max(struct wf_control *ct)
61{
62 return 1;
63}
64
65static struct wf_control_ops clamp_ops = {
66 .set_value = clamp_set,
67 .get_value = clamp_get,
68 .get_min = clamp_min,
69 .get_max = clamp_max,
70 .owner = THIS_MODULE,
71};
72
73static int __init wf_cpufreq_clamp_init(void)
74{
75 struct wf_control *clamp;
76
77 clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
78 if (clamp == NULL)
79 return -ENOMEM;
80 cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
81 clamp->ops = &clamp_ops;
82 clamp->name = "cpufreq-clamp";
83 if (wf_register_control(clamp))
84 goto fail;
85 clamp_control = clamp;
86 return 0;
87 fail:
88 kfree(clamp);
89 return -ENODEV;
90}
91
92static void __exit wf_cpufreq_clamp_exit(void)
93{
94 if (clamp_control)
95 wf_unregister_control(clamp_control);
96}
97
98
99module_init(wf_cpufreq_clamp_init);
100module_exit(wf_cpufreq_clamp_exit);
101
102MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
103MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
104MODULE_LICENSE("GPL");
105