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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
75722d39 BH |
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 | ||
b55fafc5 BH |
11 | #include <asm/prom.h> |
12 | ||
75722d39 BH |
13 | #include "windfarm.h" |
14 | ||
15 | #define VERSION "0.3" | |
16 | ||
17 | static int clamped; | |
18 | static struct wf_control *clamp_control; | |
19 | ||
20 | static 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 | ||
35 | static struct notifier_block clamp_notifier = { | |
36 | .notifier_call = clamp_notifier_call, | |
37 | }; | |
38 | ||
39 | static 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 | ||
51 | static int clamp_get(struct wf_control *ct, s32 *value) | |
52 | { | |
53 | *value = clamped; | |
54 | return 0; | |
55 | } | |
56 | ||
57 | static s32 clamp_min(struct wf_control *ct) | |
58 | { | |
59 | return 0; | |
60 | } | |
61 | ||
62 | static s32 clamp_max(struct wf_control *ct) | |
63 | { | |
64 | return 1; | |
65 | } | |
66 | ||
1ad35f6e | 67 | static const struct wf_control_ops clamp_ops = { |
75722d39 BH |
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 | ||
75 | static int __init wf_cpufreq_clamp_init(void) | |
76 | { | |
77 | struct wf_control *clamp; | |
78 | ||
79 | clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL); | |
80 | if (clamp == NULL) | |
81 | return -ENOMEM; | |
82 | cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER); | |
83 | clamp->ops = &clamp_ops; | |
84 | clamp->name = "cpufreq-clamp"; | |
85 | if (wf_register_control(clamp)) | |
86 | goto fail; | |
87 | clamp_control = clamp; | |
88 | return 0; | |
89 | fail: | |
90 | kfree(clamp); | |
91 | return -ENODEV; | |
92 | } | |
93 | ||
94 | static void __exit wf_cpufreq_clamp_exit(void) | |
95 | { | |
96 | if (clamp_control) | |
97 | wf_unregister_control(clamp_control); | |
98 | } | |
99 | ||
100 | ||
101 | module_init(wf_cpufreq_clamp_init); | |
102 | module_exit(wf_cpufreq_clamp_exit); | |
103 | ||
104 | MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); | |
105 | MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control"); | |
106 | MODULE_LICENSE("GPL"); | |
107 |