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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 *
Ralf Baechle0bb383a2015-07-07 20:56:04 +02006 * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +08007 * 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 */
Joe Perches1c5864e2016-04-05 13:28:25 -070013
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080016#include <linux/cpufreq.h>
17#include <linux/module.h>
18#include <linux/err.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080019#include <linux/delay.h>
20#include <linux/platform_device.h>
21
Ralf Baechlebdc92d742013-05-21 16:59:19 +020022#include <asm/idle.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080023
Jiaxun Yang71e2f4d2019-10-20 22:43:14 +080024#include <asm/mach-loongson2ef/loongson.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080025
26static uint nowait;
27
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080028static void (*saved_cpu_wait) (void);
29
30static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
31 unsigned long val, void *data);
32
33static struct notifier_block loongson2_cpufreq_notifier_block = {
34 .notifier_call = loongson2_cpu_freq_notifier
35};
36
37static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
38 unsigned long val, void *data)
39{
40 if (val == CPUFREQ_POSTCHANGE)
41 current_cpu_data.udelay_val = loops_per_jiffy;
42
43 return 0;
44}
45
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080046/*
47 * Here we notify other drivers of the proposed change and the final change.
48 */
49static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053050 unsigned int index)
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080051{
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080052 unsigned int freq;
53
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080054 freq =
55 ((cpu_clock_freq / 1000) *
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053056 loongson2_clockmod_table[index].driver_data) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080057
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080058 /* setting the cpu frequency */
Arnd Bergmannc02e9632020-04-09 11:02:28 +020059 loongson2_cpu_set_rate(freq);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080060
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080061 return 0;
62}
63
64static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
65{
66 int i;
Julia Lawall42913c72013-01-03 09:34:20 +000067 unsigned long rate;
68 int ret;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080069
Julia Lawall42913c72013-01-03 09:34:20 +000070 rate = cpu_clock_freq / 1000;
Arnd Bergmannc02e9632020-04-09 11:02:28 +020071 if (!rate)
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080072 return -EINVAL;
73
74 /* clock table init */
75 for (i = 2;
76 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
77 i++)
Julia Lawall42913c72013-01-03 09:34:20 +000078 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080079
Arnd Bergmannc02e9632020-04-09 11:02:28 +020080 ret = loongson2_cpu_set_rate(rate);
81 if (ret)
Aaro Koskinenf54fe642013-08-05 21:27:12 +030082 return ret;
Aaro Koskinenf54fe642013-08-05 21:27:12 +030083
Viresh Kumarc4dcc8a2019-07-16 09:36:08 +053084 cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
85 return 0;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080086}
87
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080088static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
89{
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080090 return 0;
91}
92
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080093static struct cpufreq_driver loongson2_cpufreq_driver = {
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080094 .name = "loongson2",
95 .init = loongson2_cpufreq_cpu_init,
Viresh Kumar6b0f8d72013-10-03 20:28:11 +053096 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053097 .target_index = loongson2_cpufreq_target,
Viresh Kumar652ed952014-01-09 20:38:43 +053098 .get = cpufreq_generic_get,
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080099 .exit = loongson2_cpufreq_exit,
Viresh Kumar6b0f8d72013-10-03 20:28:11 +0530100 .attr = cpufreq_generic_attr,
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800101};
102
Arvind Yadava804d512017-08-13 15:10:06 +0530103static const struct platform_device_id platform_device_ids[] = {
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800104 {
105 .name = "loongson2_cpufreq",
106 },
107 {}
108};
109
110MODULE_DEVICE_TABLE(platform, platform_device_ids);
111
112static struct platform_driver platform_driver = {
113 .driver = {
114 .name = "loongson2_cpufreq",
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800115 },
116 .id_table = platform_device_ids,
117};
118
Ralf Baechle95cf14682012-08-01 17:15:32 +0200119/*
120 * This is the simple version of Loongson-2 wait, Maybe we need do this in
121 * interrupt disabled context.
122 */
123
124static DEFINE_SPINLOCK(loongson2_wait_lock);
125
126static void loongson2_cpu_wait(void)
127{
128 unsigned long flags;
129 u32 cpu_freq;
130
131 spin_lock_irqsave(&loongson2_wait_lock, flags);
Alexandre Oliva1250c1a2020-01-21 09:30:45 -0300132 cpu_freq = readl(LOONGSON_CHIPCFG);
133 /* Put CPU into wait mode */
134 writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
135 /* Restore CPU state */
136 writel(cpu_freq, LOONGSON_CHIPCFG);
Ralf Baechle95cf14682012-08-01 17:15:32 +0200137 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
Ralf Baechlefb40bc32013-05-21 14:05:27 +0200138 local_irq_enable();
Ralf Baechle95cf14682012-08-01 17:15:32 +0200139}
140
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800141static int __init cpufreq_init(void)
142{
143 int ret;
144
145 /* Register platform stuff */
146 ret = platform_driver_register(&platform_driver);
147 if (ret)
148 return ret;
149
Joe Perches1c5864e2016-04-05 13:28:25 -0700150 pr_info("Loongson-2F CPU frequency driver\n");
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800151
152 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
153 CPUFREQ_TRANSITION_NOTIFIER);
154
155 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
156
157 if (!ret && !nowait) {
158 saved_cpu_wait = cpu_wait;
159 cpu_wait = loongson2_cpu_wait;
160 }
161
162 return ret;
163}
164
165static void __exit cpufreq_exit(void)
166{
167 if (!nowait && saved_cpu_wait)
168 cpu_wait = saved_cpu_wait;
169 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
170 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
171 CPUFREQ_TRANSITION_NOTIFIER);
172
173 platform_driver_unregister(&platform_driver);
174}
175
176module_init(cpufreq_init);
177module_exit(cpufreq_exit);
178
179module_param(nowait, uint, 0644);
180MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
181
182MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
183MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
184MODULE_LICENSE("GPL");