1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/types.h>
  3#include <linux/errno.h>
  4#include <linux/kernel.h>
  5#include <linux/delay.h>
  6#include <linux/pm_qos.h>
  7#include <linux/slab.h>
  8#include <linux/init.h>
  9#include <linux/wait.h>
 10#include <linux/cpu.h>
 11#include <linux/cpufreq.h>
 12
 
 
 13#include "windfarm.h"
 14
 15#define VERSION "0.3"
 16
 17static int clamped;
 18static struct wf_control *clamp_control;
 19static struct freq_qos_request qos_req;
 20static unsigned int min_freq, max_freq;
 21
 22static int clamp_set(struct wf_control *ct, s32 value)
 
 23{
 24	unsigned int freq;
 
 
 
 
 25
 26	if (value) {
 27		freq = min_freq;
 
 
 
 
 
 
 
 
 
 
 
 28		printk(KERN_INFO "windfarm: Clamping CPU frequency to "
 29		       "minimum !\n");
 30	} else {
 31		freq = max_freq;
 32		printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
 33	}
 34	clamped = value;
 35
 36	return freq_qos_update_request(&qos_req, freq);
 37}
 38
 39static int clamp_get(struct wf_control *ct, s32 *value)
 40{
 41	*value = clamped;
 42	return 0;
 43}
 44
 45static s32 clamp_min(struct wf_control *ct)
 46{
 47	return 0;
 48}
 49
 50static s32 clamp_max(struct wf_control *ct)
 51{
 52	return 1;
 53}
 54
 55static const struct wf_control_ops clamp_ops = {
 56	.set_value	= clamp_set,
 57	.get_value	= clamp_get,
 58	.get_min	= clamp_min,
 59	.get_max	= clamp_max,
 60	.owner		= THIS_MODULE,
 61};
 62
 63static int __init wf_cpufreq_clamp_init(void)
 64{
 65	struct cpufreq_policy *policy;
 66	struct wf_control *clamp;
 67	struct device *dev;
 68	int ret;
 69
 70	policy = cpufreq_cpu_get(0);
 71	if (!policy) {
 72		pr_warn("%s: cpufreq policy not found cpu0\n", __func__);
 73		return -EPROBE_DEFER;
 74	}
 75
 76	min_freq = policy->cpuinfo.min_freq;
 77	max_freq = policy->cpuinfo.max_freq;
 78
 79	ret = freq_qos_add_request(&policy->constraints, &qos_req, FREQ_QOS_MAX,
 80				   max_freq);
 81
 82	cpufreq_cpu_put(policy);
 83
 84	if (ret < 0) {
 85		pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
 86		       ret);
 87		return ret;
 88	}
 89
 90	dev = get_cpu_device(0);
 91	if (unlikely(!dev)) {
 92		pr_warn("%s: No cpu device for cpu0\n", __func__);
 93		ret = -ENODEV;
 94		goto fail;
 95	}
 96
 97	clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
 98	if (clamp == NULL) {
 99		ret = -ENOMEM;
100		goto fail;
101	}
102
103	clamp->ops = &clamp_ops;
104	clamp->name = "cpufreq-clamp";
105	ret = wf_register_control(clamp);
106	if (ret)
107		goto free;
108
109	clamp_control = clamp;
110	return 0;
111
112 free:
113	kfree(clamp);
114 fail:
115	freq_qos_remove_request(&qos_req);
116	return ret;
117}
118
119static void __exit wf_cpufreq_clamp_exit(void)
120{
121	if (clamp_control) {
122		wf_unregister_control(clamp_control);
123		freq_qos_remove_request(&qos_req);
124	}
125}
126
127
128module_init(wf_cpufreq_clamp_init);
129module_exit(wf_cpufreq_clamp_exit);
130
131MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
132MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
133MODULE_LICENSE("GPL");
134

 
  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
 16static int clamped;
 17static struct wf_control *clamp_control;
 
 
 18
 19static 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
 34static struct notifier_block clamp_notifier = {
 35	.notifier_call = clamp_notifier_call,
 36};
 37
 38static 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
 50static int clamp_get(struct wf_control *ct, s32 *value)
 51{
 52	*value = clamped;
 53	return 0;
 54}
 55
 56static s32 clamp_min(struct wf_control *ct)
 57{
 58	return 0;
 59}
 60
 61static s32 clamp_max(struct wf_control *ct)
 62{
 63	return 1;
 64}
 65
 66static const 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
 74static 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
 93static void __exit wf_cpufreq_clamp_exit(void)
 94{
 95	if (clamp_control)
 96		wf_unregister_control(clamp_control);
 
 
 97}
 98
 99
100module_init(wf_cpufreq_clamp_init);
101module_exit(wf_cpufreq_clamp_exit);
102
103MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
104MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
105MODULE_LICENSE("GPL");
106