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1/*
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. & Institute 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
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/cpufreq.h>
17#include <linux/module.h>
18#include <linux/err.h>
19#include <linux/delay.h>
20#include <linux/platform_device.h>
21
22#include <asm/idle.h>
23
24#include <asm/mach-loongson2ef/loongson.h>
25
26static uint nowait;
27
28static 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
46/*
47 * Here we notify other drivers of the proposed change and the final change.
48 */
49static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
50 unsigned int index)
51{
52 unsigned int freq;
53
54 freq =
55 ((cpu_clock_freq / 1000) *
56 loongson2_clockmod_table[index].driver_data) / 8;
57
58 /* setting the cpu frequency */
59 loongson2_cpu_set_rate(freq);
60
61 return 0;
62}
63
64static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
65{
66 int i;
67 unsigned long rate;
68 int ret;
69
70 rate = cpu_clock_freq / 1000;
71 if (!rate)
72 return -EINVAL;
73
74 /* clock table init */
75 for (i = 2;
76 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
77 i++)
78 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
79
80 ret = loongson2_cpu_set_rate(rate);
81 if (ret)
82 return ret;
83
84 cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
85 return 0;
86}
87
88static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
89{
90 return 0;
91}
92
93static struct cpufreq_driver loongson2_cpufreq_driver = {
94 .name = "loongson2",
95 .init = loongson2_cpufreq_cpu_init,
96 .verify = cpufreq_generic_frequency_table_verify,
97 .target_index = loongson2_cpufreq_target,
98 .get = cpufreq_generic_get,
99 .exit = loongson2_cpufreq_exit,
100 .attr = cpufreq_generic_attr,
101};
102
103static const struct platform_device_id platform_device_ids[] = {
104 {
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",
115 },
116 .id_table = platform_device_ids,
117};
118
119/*
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);
132 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);
137 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
138 local_irq_enable();
139}
140
141static 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
150 pr_info("Loongson-2F CPU frequency driver\n");
151
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");
1/*
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. & Institute 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
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/cpufreq.h>
17#include <linux/module.h>
18#include <linux/err.h>
19#include <linux/sched.h> /* set_cpus_allowed() */
20#include <linux/delay.h>
21#include <linux/platform_device.h>
22
23#include <asm/clock.h>
24#include <asm/idle.h>
25
26#include <asm/mach-loongson64/loongson.h>
27
28static uint nowait;
29
30static void (*saved_cpu_wait) (void);
31
32static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
33 unsigned long val, void *data);
34
35static struct notifier_block loongson2_cpufreq_notifier_block = {
36 .notifier_call = loongson2_cpu_freq_notifier
37};
38
39static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
40 unsigned long val, void *data)
41{
42 if (val == CPUFREQ_POSTCHANGE)
43 current_cpu_data.udelay_val = loops_per_jiffy;
44
45 return 0;
46}
47
48/*
49 * Here we notify other drivers of the proposed change and the final change.
50 */
51static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
52 unsigned int index)
53{
54 unsigned int freq;
55
56 freq =
57 ((cpu_clock_freq / 1000) *
58 loongson2_clockmod_table[index].driver_data) / 8;
59
60 /* setting the cpu frequency */
61 clk_set_rate(policy->clk, freq * 1000);
62
63 return 0;
64}
65
66static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
67{
68 struct clk *cpuclk;
69 int i;
70 unsigned long rate;
71 int ret;
72
73 cpuclk = clk_get(NULL, "cpu_clk");
74 if (IS_ERR(cpuclk)) {
75 pr_err("couldn't get CPU clk\n");
76 return PTR_ERR(cpuclk);
77 }
78
79 rate = cpu_clock_freq / 1000;
80 if (!rate) {
81 clk_put(cpuclk);
82 return -EINVAL;
83 }
84
85 /* clock table init */
86 for (i = 2;
87 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
88 i++)
89 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
90
91 ret = clk_set_rate(cpuclk, rate * 1000);
92 if (ret) {
93 clk_put(cpuclk);
94 return ret;
95 }
96
97 policy->clk = cpuclk;
98 cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
99 return 0;
100}
101
102static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
103{
104 clk_put(policy->clk);
105 return 0;
106}
107
108static struct cpufreq_driver loongson2_cpufreq_driver = {
109 .name = "loongson2",
110 .init = loongson2_cpufreq_cpu_init,
111 .verify = cpufreq_generic_frequency_table_verify,
112 .target_index = loongson2_cpufreq_target,
113 .get = cpufreq_generic_get,
114 .exit = loongson2_cpufreq_exit,
115 .attr = cpufreq_generic_attr,
116};
117
118static const struct platform_device_id platform_device_ids[] = {
119 {
120 .name = "loongson2_cpufreq",
121 },
122 {}
123};
124
125MODULE_DEVICE_TABLE(platform, platform_device_ids);
126
127static struct platform_driver platform_driver = {
128 .driver = {
129 .name = "loongson2_cpufreq",
130 },
131 .id_table = platform_device_ids,
132};
133
134/*
135 * This is the simple version of Loongson-2 wait, Maybe we need do this in
136 * interrupt disabled context.
137 */
138
139static DEFINE_SPINLOCK(loongson2_wait_lock);
140
141static void loongson2_cpu_wait(void)
142{
143 unsigned long flags;
144 u32 cpu_freq;
145
146 spin_lock_irqsave(&loongson2_wait_lock, flags);
147 cpu_freq = LOONGSON_CHIPCFG(0);
148 LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */
149 LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
150 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
151 local_irq_enable();
152}
153
154static int __init cpufreq_init(void)
155{
156 int ret;
157
158 /* Register platform stuff */
159 ret = platform_driver_register(&platform_driver);
160 if (ret)
161 return ret;
162
163 pr_info("Loongson-2F CPU frequency driver\n");
164
165 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
166 CPUFREQ_TRANSITION_NOTIFIER);
167
168 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
169
170 if (!ret && !nowait) {
171 saved_cpu_wait = cpu_wait;
172 cpu_wait = loongson2_cpu_wait;
173 }
174
175 return ret;
176}
177
178static void __exit cpufreq_exit(void)
179{
180 if (!nowait && saved_cpu_wait)
181 cpu_wait = saved_cpu_wait;
182 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
183 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
184 CPUFREQ_TRANSITION_NOTIFIER);
185
186 platform_driver_unregister(&platform_driver);
187}
188
189module_init(cpufreq_init);
190module_exit(cpufreq_exit);
191
192module_param(nowait, uint, 0644);
193MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
194
195MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
196MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
197MODULE_LICENSE("GPL");