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Wu Zhangjinf8ede0f2009-11-17 01:32:59 +08001/*
2 * Cpufreq driver for the loongson-2 processors
3 *
4 * The 2E revision of loongson processor not support this feature.
5 *
6 * Copyright (C) 2006 - 2008 Lemote Inc. & Insititute of Computing Technology
7 * Author: Yanhua, yanh@lemote.com
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13#include <linux/cpufreq.h>
14#include <linux/module.h>
15#include <linux/err.h>
16#include <linux/sched.h> /* set_cpus_allowed() */
17#include <linux/delay.h>
18#include <linux/platform_device.h>
19
20#include <asm/clock.h>
Ralf Baechlebdc92d742013-05-21 16:59:19 +020021#include <asm/idle.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080022
Ralf Baechle95cf1462012-08-01 17:15:32 +020023#include <asm/mach-loongson/loongson.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080024
25static uint nowait;
26
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080027static void (*saved_cpu_wait) (void);
28
29static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
30 unsigned long val, void *data);
31
32static struct notifier_block loongson2_cpufreq_notifier_block = {
33 .notifier_call = loongson2_cpu_freq_notifier
34};
35
36static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
37 unsigned long val, void *data)
38{
39 if (val == CPUFREQ_POSTCHANGE)
40 current_cpu_data.udelay_val = loops_per_jiffy;
41
42 return 0;
43}
44
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080045/*
46 * Here we notify other drivers of the proposed change and the final change.
47 */
48static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053049 unsigned int index)
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080050{
51 unsigned int cpu = policy->cpu;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080052 cpumask_t cpus_allowed;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080053 unsigned int freq;
54
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080055 cpus_allowed = current->cpus_allowed;
Julia Lawalled1bbde2010-03-26 23:03:07 +010056 set_cpus_allowed_ptr(current, cpumask_of(cpu));
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080057
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080058 freq =
59 ((cpu_clock_freq / 1000) *
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053060 loongson2_clockmod_table[index].driver_data) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080061
Julia Lawalled1bbde2010-03-26 23:03:07 +010062 set_cpus_allowed_ptr(current, &cpus_allowed);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080063
64 /* setting the cpu frequency */
Aaro Koskinen8e8acb32014-04-03 22:24:01 +030065 clk_set_rate(policy->clk, freq * 1000);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080066
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080067 return 0;
68}
69
70static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
71{
Viresh Kumar05ed6722014-04-02 10:14:24 +053072 struct clk *cpuclk;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080073 int i;
Julia Lawall42913c72013-01-03 09:34:20 +000074 unsigned long rate;
75 int ret;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080076
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080077 cpuclk = clk_get(NULL, "cpu_clk");
78 if (IS_ERR(cpuclk)) {
79 printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
80 return PTR_ERR(cpuclk);
81 }
82
Julia Lawall42913c72013-01-03 09:34:20 +000083 rate = cpu_clock_freq / 1000;
84 if (!rate) {
85 clk_put(cpuclk);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080086 return -EINVAL;
Julia Lawall42913c72013-01-03 09:34:20 +000087 }
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080088
89 /* clock table init */
90 for (i = 2;
91 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
92 i++)
Julia Lawall42913c72013-01-03 09:34:20 +000093 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080094
Aaro Koskinen8e8acb32014-04-03 22:24:01 +030095 ret = clk_set_rate(cpuclk, rate * 1000);
Aaro Koskinenf54fe642013-08-05 21:27:12 +030096 if (ret) {
97 clk_put(cpuclk);
98 return ret;
99 }
100
Viresh Kumar652ed952014-01-09 20:38:43 +0530101 policy->clk = cpuclk;
Viresh Kumare0b2da52013-10-03 20:29:16 +0530102 return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800103}
104
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800105static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
106{
Viresh Kumar652ed952014-01-09 20:38:43 +0530107 clk_put(policy->clk);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800108 return 0;
109}
110
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800111static struct cpufreq_driver loongson2_cpufreq_driver = {
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800112 .name = "loongson2",
113 .init = loongson2_cpufreq_cpu_init,
Viresh Kumar6b0f8d72013-10-03 20:28:11 +0530114 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530115 .target_index = loongson2_cpufreq_target,
Viresh Kumar652ed952014-01-09 20:38:43 +0530116 .get = cpufreq_generic_get,
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800117 .exit = loongson2_cpufreq_exit,
Viresh Kumar6b0f8d72013-10-03 20:28:11 +0530118 .attr = cpufreq_generic_attr,
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800119};
120
121static struct platform_device_id platform_device_ids[] = {
122 {
123 .name = "loongson2_cpufreq",
124 },
125 {}
126};
127
128MODULE_DEVICE_TABLE(platform, platform_device_ids);
129
130static struct platform_driver platform_driver = {
131 .driver = {
132 .name = "loongson2_cpufreq",
133 .owner = THIS_MODULE,
134 },
135 .id_table = platform_device_ids,
136};
137
Ralf Baechle95cf1462012-08-01 17:15:32 +0200138/*
139 * This is the simple version of Loongson-2 wait, Maybe we need do this in
140 * interrupt disabled context.
141 */
142
143static DEFINE_SPINLOCK(loongson2_wait_lock);
144
145static void loongson2_cpu_wait(void)
146{
147 unsigned long flags;
148 u32 cpu_freq;
149
150 spin_lock_irqsave(&loongson2_wait_lock, flags);
Huacai Chen140e39c2014-06-26 11:41:27 +0800151 cpu_freq = LOONGSON_CHIPCFG(0);
152 LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */
153 LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
Ralf Baechle95cf1462012-08-01 17:15:32 +0200154 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
Ralf Baechlefb40bc32013-05-21 14:05:27 +0200155 local_irq_enable();
Ralf Baechle95cf1462012-08-01 17:15:32 +0200156}
157
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800158static int __init cpufreq_init(void)
159{
160 int ret;
161
162 /* Register platform stuff */
163 ret = platform_driver_register(&platform_driver);
164 if (ret)
165 return ret;
166
167 pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
168
169 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
170 CPUFREQ_TRANSITION_NOTIFIER);
171
172 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
173
174 if (!ret && !nowait) {
175 saved_cpu_wait = cpu_wait;
176 cpu_wait = loongson2_cpu_wait;
177 }
178
179 return ret;
180}
181
182static void __exit cpufreq_exit(void)
183{
184 if (!nowait && saved_cpu_wait)
185 cpu_wait = saved_cpu_wait;
186 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
187 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
188 CPUFREQ_TRANSITION_NOTIFIER);
189
190 platform_driver_unregister(&platform_driver);
191}
192
193module_init(cpufreq_init);
194module_exit(cpufreq_exit);
195
196module_param(nowait, uint, 0644);
197MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
198
199MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
200MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
201MODULE_LICENSE("GPL");