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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#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>
21#include <asm/idle.h>
22
23#include <asm/mach-loongson64/loongson.h>
24
25static uint nowait;
26
27static 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
45/*
46 * Here we notify other drivers of the proposed change and the final change.
47 */
48static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
49 unsigned int index)
50{
51 unsigned int cpu = policy->cpu;
52 cpumask_t cpus_allowed;
53 unsigned int freq;
54
55 cpus_allowed = current->cpus_allowed;
56 set_cpus_allowed_ptr(current, cpumask_of(cpu));
57
58 freq =
59 ((cpu_clock_freq / 1000) *
60 loongson2_clockmod_table[index].driver_data) / 8;
61
62 set_cpus_allowed_ptr(current, &cpus_allowed);
63
64 /* setting the cpu frequency */
65 clk_set_rate(policy->clk, freq * 1000);
66
67 return 0;
68}
69
70static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
71{
72 struct clk *cpuclk;
73 int i;
74 unsigned long rate;
75 int ret;
76
77 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
83 rate = cpu_clock_freq / 1000;
84 if (!rate) {
85 clk_put(cpuclk);
86 return -EINVAL;
87 }
88
89 /* clock table init */
90 for (i = 2;
91 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
92 i++)
93 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
94
95 ret = clk_set_rate(cpuclk, rate * 1000);
96 if (ret) {
97 clk_put(cpuclk);
98 return ret;
99 }
100
101 policy->clk = cpuclk;
102 return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
103}
104
105static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
106{
107 clk_put(policy->clk);
108 return 0;
109}
110
111static struct cpufreq_driver loongson2_cpufreq_driver = {
112 .name = "loongson2",
113 .init = loongson2_cpufreq_cpu_init,
114 .verify = cpufreq_generic_frequency_table_verify,
115 .target_index = loongson2_cpufreq_target,
116 .get = cpufreq_generic_get,
117 .exit = loongson2_cpufreq_exit,
118 .attr = cpufreq_generic_attr,
119};
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 },
134 .id_table = platform_device_ids,
135};
136
137/*
138 * This is the simple version of Loongson-2 wait, Maybe we need do this in
139 * interrupt disabled context.
140 */
141
142static DEFINE_SPINLOCK(loongson2_wait_lock);
143
144static void loongson2_cpu_wait(void)
145{
146 unsigned long flags;
147 u32 cpu_freq;
148
149 spin_lock_irqsave(&loongson2_wait_lock, flags);
150 cpu_freq = LOONGSON_CHIPCFG(0);
151 LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */
152 LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
153 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
154 local_irq_enable();
155}
156
157static int __init cpufreq_init(void)
158{
159 int ret;
160
161 /* Register platform stuff */
162 ret = platform_driver_register(&platform_driver);
163 if (ret)
164 return ret;
165
166 pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
167
168 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
169 CPUFREQ_TRANSITION_NOTIFIER);
170
171 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
172
173 if (!ret && !nowait) {
174 saved_cpu_wait = cpu_wait;
175 cpu_wait = loongson2_cpu_wait;
176 }
177
178 return ret;
179}
180
181static void __exit cpufreq_exit(void)
182{
183 if (!nowait && saved_cpu_wait)
184 cpu_wait = saved_cpu_wait;
185 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
186 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
187 CPUFREQ_TRANSITION_NOTIFIER);
188
189 platform_driver_unregister(&platform_driver);
190}
191
192module_init(cpufreq_init);
193module_exit(cpufreq_exit);
194
195module_param(nowait, uint, 0644);
196MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
197
198MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
199MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
200MODULE_LICENSE("GPL");