1 #include <linux/types.h> 2 #include <linux/errno.h> 3 #include <linux/kernel.h> 4 #include <linux/delay.h> 5 #include <linux/slab.h> 6 #include <linux/init.h> 7 #include <linux/wait.h> 8 #include <linux/cpufreq.h> 9 10 #include <asm/prom.h> 11 12 #include "windfarm.h" 13 14 #define VERSION "0.3" 15 16 static int clamped; 17 static struct wf_control *clamp_control; 18 19 static int clamp_notifier_call(struct notifier_block *self, 20 unsigned long event, void *data) 21 { 22 struct cpufreq_policy *p = data; 23 unsigned long max_freq; 24 25 if (event != CPUFREQ_ADJUST) 26 return 0; 27 28 max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq); 29 cpufreq_verify_within_limits(p, 0, max_freq); 30 31 return 0; 32 } 33 34 static struct notifier_block clamp_notifier = { 35 .notifier_call = clamp_notifier_call, 36 }; 37 38 static int clamp_set(struct wf_control *ct, s32 value) 39 { 40 if (value) 41 printk(KERN_INFO "windfarm: Clamping CPU frequency to " 42 "minimum !\n"); 43 else 44 printk(KERN_INFO "windfarm: CPU frequency unclamped !\n"); 45 clamped = value; 46 cpufreq_update_policy(0); 47 return 0; 48 } 49 50 static int clamp_get(struct wf_control *ct, s32 *value) 51 { 52 *value = clamped; 53 return 0; 54 } 55 56 static s32 clamp_min(struct wf_control *ct) 57 { 58 return 0; 59 } 60 61 static s32 clamp_max(struct wf_control *ct) 62 { 63 return 1; 64 } 65 66 static struct wf_control_ops clamp_ops = { 67 .set_value = clamp_set, 68 .get_value = clamp_get, 69 .get_min = clamp_min, 70 .get_max = clamp_max, 71 .owner = THIS_MODULE, 72 }; 73 74 static int __init wf_cpufreq_clamp_init(void) 75 { 76 struct wf_control *clamp; 77 78 clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL); 79 if (clamp == NULL) 80 return -ENOMEM; 81 cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER); 82 clamp->ops = &clamp_ops; 83 clamp->name = "cpufreq-clamp"; 84 if (wf_register_control(clamp)) 85 goto fail; 86 clamp_control = clamp; 87 return 0; 88 fail: 89 kfree(clamp); 90 return -ENODEV; 91 } 92 93 static void __exit wf_cpufreq_clamp_exit(void) 94 { 95 if (clamp_control) 96 wf_unregister_control(clamp_control); 97 } 98 99 100 module_init(wf_cpufreq_clamp_init); 101 module_exit(wf_cpufreq_clamp_exit); 102 103 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 104 MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control"); 105 MODULE_LICENSE("GPL"); 106 107