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 <asm/prom.h>
12
13#include "windfarm.h"
14
15#define VERSION "0.3"
16
17static int clamped;
18static struct wf_control *clamp_control;
19
20static int clamp_notifier_call(struct notifier_block *self,
21 unsigned long event, void *data)
22{
23 struct cpufreq_policy *p = data;
24 unsigned long max_freq;
25
26 if (event != CPUFREQ_ADJUST)
27 return 0;
28
29 max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
30 cpufreq_verify_within_limits(p, 0, max_freq);
31
32 return 0;
33}
34
35static struct notifier_block clamp_notifier = {
36 .notifier_call = clamp_notifier_call,
37};
38
39static int clamp_set(struct wf_control *ct, s32 value)
40{
41 if (value)
42 printk(KERN_INFO "windfarm: Clamping CPU frequency to "
43 "minimum !\n");
44 else
45 printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
46 clamped = value;
47 cpufreq_update_policy(0);
48 return 0;
49}
50
51static int clamp_get(struct wf_control *ct, s32 *value)
52{
53 *value = clamped;
54 return 0;
55}
56
57static s32 clamp_min(struct wf_control *ct)
58{
59 return 0;
60}
61
62static s32 clamp_max(struct wf_control *ct)
63{
64 return 1;
65}
66
67static struct wf_control_ops clamp_ops = {
68 .set_value = clamp_set,
69 .get_value = clamp_get,
70 .get_min = clamp_min,
71 .get_max = clamp_max,
72 .owner = THIS_MODULE,
73};
74
75static int __init wf_cpufreq_clamp_init(void)
76{
77 struct wf_control *clamp;
78
79 /* Don't register on old machines that use therm_pm72 for now */
80 if (machine_is_compatible("PowerMac7,2") ||
81 machine_is_compatible("PowerMac7,3") ||
82 machine_is_compatible("RackMac3,1"))
83 return -ENODEV;
84
85 clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
86 if (clamp == NULL)
87 return -ENOMEM;
88 cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
89 clamp->ops = &clamp_ops;
90 clamp->name = "cpufreq-clamp";
91 if (wf_register_control(clamp))
92 goto fail;
93 clamp_control = clamp;
94 return 0;
95 fail:
96 kfree(clamp);
97 return -ENODEV;
98}
99
100static void __exit wf_cpufreq_clamp_exit(void)
101{
102 if (clamp_control)
103 wf_unregister_control(clamp_control);
104}
105
106
107module_init(wf_cpufreq_clamp_init);
108module_exit(wf_cpufreq_clamp_exit);
109
110MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
111MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
112MODULE_LICENSE("GPL");
113