| 1 | |
| 2 | #include <linux/types.h>
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| 3 | #include <linux/errno.h>
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| 4 | #include <linux/kernel.h>
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| 5 | #include <linux/delay.h>
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| 6 | #include <linux/pm_qos.h>
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| 7 | #include <linux/slab.h>
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| 8 | #include <linux/init.h>
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| 9 | #include <linux/wait.h>
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| 10 | #include <linux/cpu.h>
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| 11 | #include <linux/cpufreq.h>
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| 12 |
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| 13 | #include "windfarm.h"
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| 14 |
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| 15 | #define VERSION "0.3"
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| 16 |
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| 17 | static int clamped;
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| 18 | static struct wf_control *clamp_control;
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| 19 | static struct freq_qos_request qos_req;
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| 20 | static unsigned int min_freq, max_freq;
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| 21 |
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| 22 | static int clamp_set(struct wf_control *ct, s32 value)
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| 23 | {
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| 24 | unsigned int freq;
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| 25 |
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| 26 | if (value) {
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| 27 | freq = min_freq;
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| 28 | printk(KERN_INFO "windfarm: Clamping CPU frequency to "
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| 29 | "minimum !\n");
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| 30 | } else {
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| 31 | freq = max_freq;
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| 32 | printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
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| 33 | }
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| 34 | clamped = value;
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| 35 |
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| 36 | return freq_qos_update_request(&qos_req, freq);
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| 37 | }
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| 38 |
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| 39 | static int clamp_get(struct wf_control *ct, s32 *value)
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| 40 | {
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| 41 | *value = clamped;
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| 42 | return 0;
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| 43 | }
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| 44 |
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| 45 | static s32 clamp_min(struct wf_control *ct)
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| 46 | {
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| 47 | return 0;
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| 48 | }
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| 49 |
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| 50 | static s32 clamp_max(struct wf_control *ct)
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| 51 | {
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| 52 | return 1;
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| 53 | }
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| 54 |
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| 55 | static const struct wf_control_ops clamp_ops = {
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| 56 | .set_value = clamp_set,
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| 57 | .get_value = clamp_get,
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| 58 | .get_min = clamp_min,
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| 59 | .get_max = clamp_max,
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| 60 | .owner = THIS_MODULE,
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| 61 | };
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| 62 |
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| 63 | static int __init wf_cpufreq_clamp_init(void)
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| 64 | {
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| 65 | struct cpufreq_policy *policy;
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| 66 | struct wf_control *clamp;
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| 67 | struct device *dev;
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| 68 | int ret;
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| 69 |
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| 70 | policy = cpufreq_cpu_get(0);
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| 71 | if (!policy) {
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| 72 | pr_warn("%s: cpufreq policy not found cpu0\n", __func__);
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| 73 | return -EPROBE_DEFER;
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| 74 | }
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| 75 |
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| 76 | min_freq = policy->cpuinfo.min_freq;
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| 77 | max_freq = policy->cpuinfo.max_freq;
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| 78 |
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| 79 | ret = freq_qos_add_request(&policy->constraints, &qos_req, FREQ_QOS_MAX,
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| 80 | max_freq);
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| 81 |
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| 82 | cpufreq_cpu_put(policy);
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| 83 |
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| 84 | if (ret < 0) {
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| 85 | pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
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| 86 | ret);
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| 87 | return ret;
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| 88 | }
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| 89 |
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| 90 | dev = get_cpu_device(0);
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| 91 | if (unlikely(!dev)) {
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| 92 | pr_warn("%s: No cpu device for cpu0\n", __func__);
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| 93 | ret = -ENODEV;
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| 94 | goto fail;
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| 95 | }
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| 96 |
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| 97 | clamp = kmalloc_obj(struct wf_control);
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| 98 | if (clamp == NULL) {
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| 99 | ret = -ENOMEM;
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| 100 | goto fail;
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| 101 | }
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| 102 |
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| 103 | clamp->ops = &clamp_ops;
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| 104 | clamp->name = "cpufreq-clamp";
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| 105 | ret = wf_register_control(clamp);
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| 106 | if (ret)
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| 107 | goto free;
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| 108 |
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| 109 | clamp_control = clamp;
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| 110 | return 0;
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| 111 |
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| 112 | free:
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| 113 | kfree(clamp);
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| 114 | fail:
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| 115 | freq_qos_remove_request(&qos_req);
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| 116 | return ret;
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| 117 | }
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| 118 |
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| 119 | static void __exit wf_cpufreq_clamp_exit(void)
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| 120 | {
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| 121 | if (clamp_control) {
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| 122 | wf_unregister_control(clamp_control);
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| 123 | freq_qos_remove_request(&qos_req);
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| 124 | }
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| 125 | }
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| 126 |
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| 127 |
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| 128 | module_init(wf_cpufreq_clamp_init);
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| 129 | module_exit(wf_cpufreq_clamp_exit);
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| 130 |
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| 131 | MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
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| 132 | MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
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| 133 | MODULE_LICENSE("GPL");
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| 134 |
|