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f8ede0f7 WZ |
1 | /* |
2 | * Cpufreq driver for the loongson-2 processors | |
3 | * | |
4 | * The 2E revision of loongson processor not support this feature. | |
5 | * | |
0bb383a2 | 6 | * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology |
f8ede0f7 WZ |
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 | */ | |
1c5864e2 JP |
13 | |
14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
15 | ||
f8ede0f7 WZ |
16 | #include <linux/cpufreq.h> |
17 | #include <linux/module.h> | |
18 | #include <linux/err.h> | |
f8ede0f7 WZ |
19 | #include <linux/delay.h> |
20 | #include <linux/platform_device.h> | |
21 | ||
bdc92d74 | 22 | #include <asm/idle.h> |
f8ede0f7 | 23 | |
71e2f4dd | 24 | #include <asm/mach-loongson2ef/loongson.h> |
f8ede0f7 WZ |
25 | |
26 | static uint nowait; | |
27 | ||
f8ede0f7 WZ |
28 | static void (*saved_cpu_wait) (void); |
29 | ||
30 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, | |
31 | unsigned long val, void *data); | |
32 | ||
33 | static struct notifier_block loongson2_cpufreq_notifier_block = { | |
34 | .notifier_call = loongson2_cpu_freq_notifier | |
35 | }; | |
36 | ||
37 | static 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 | ||
f8ede0f7 WZ |
46 | /* |
47 | * Here we notify other drivers of the proposed change and the final change. | |
48 | */ | |
49 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, | |
9c0ebcf7 | 50 | unsigned int index) |
f8ede0f7 | 51 | { |
f8ede0f7 WZ |
52 | unsigned int freq; |
53 | ||
f8ede0f7 WZ |
54 | freq = |
55 | ((cpu_clock_freq / 1000) * | |
9c0ebcf7 | 56 | loongson2_clockmod_table[index].driver_data) / 8; |
f8ede0f7 | 57 | |
f8ede0f7 | 58 | /* setting the cpu frequency */ |
c02e9630 | 59 | loongson2_cpu_set_rate(freq); |
f8ede0f7 | 60 | |
f8ede0f7 WZ |
61 | return 0; |
62 | } | |
63 | ||
64 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
65 | { | |
66 | int i; | |
42913c79 JL |
67 | unsigned long rate; |
68 | int ret; | |
f8ede0f7 | 69 | |
42913c79 | 70 | rate = cpu_clock_freq / 1000; |
c02e9630 | 71 | if (!rate) |
f8ede0f7 WZ |
72 | return -EINVAL; |
73 | ||
74 | /* clock table init */ | |
75 | for (i = 2; | |
76 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
77 | i++) | |
42913c79 | 78 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 | 79 | |
c02e9630 AB |
80 | ret = loongson2_cpu_set_rate(rate); |
81 | if (ret) | |
f54fe64d | 82 | return ret; |
f54fe64d | 83 | |
c4dcc8a1 VK |
84 | cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); |
85 | return 0; | |
f8ede0f7 WZ |
86 | } |
87 | ||
f8ede0f7 WZ |
88 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
89 | { | |
f8ede0f7 WZ |
90 | return 0; |
91 | } | |
92 | ||
f8ede0f7 | 93 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
f8ede0f7 WZ |
94 | .name = "loongson2", |
95 | .init = loongson2_cpufreq_cpu_init, | |
6b0f8d73 | 96 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 97 | .target_index = loongson2_cpufreq_target, |
652ed95d | 98 | .get = cpufreq_generic_get, |
f8ede0f7 | 99 | .exit = loongson2_cpufreq_exit, |
6b0f8d73 | 100 | .attr = cpufreq_generic_attr, |
f8ede0f7 WZ |
101 | }; |
102 | ||
a804d510 | 103 | static const struct platform_device_id platform_device_ids[] = { |
f8ede0f7 WZ |
104 | { |
105 | .name = "loongson2_cpufreq", | |
106 | }, | |
107 | {} | |
108 | }; | |
109 | ||
110 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
111 | ||
112 | static struct platform_driver platform_driver = { | |
113 | .driver = { | |
114 | .name = "loongson2_cpufreq", | |
f8ede0f7 WZ |
115 | }, |
116 | .id_table = platform_device_ids, | |
117 | }; | |
118 | ||
95cf1468 RB |
119 | /* |
120 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
121 | * interrupt disabled context. | |
122 | */ | |
123 | ||
124 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
125 | ||
126 | static void loongson2_cpu_wait(void) | |
127 | { | |
128 | unsigned long flags; | |
129 | u32 cpu_freq; | |
130 | ||
131 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
1250c1a5 AO |
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); | |
95cf1468 | 137 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 138 | local_irq_enable(); |
95cf1468 RB |
139 | } |
140 | ||
f8ede0f7 WZ |
141 | static 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 | ||
1c5864e2 | 150 | pr_info("Loongson-2F CPU frequency driver\n"); |
f8ede0f7 WZ |
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 | ||
165 | static 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 | ||
176 | module_init(cpufreq_init); | |
177 | module_exit(cpufreq_exit); | |
178 | ||
179 | module_param(nowait, uint, 0644); | |
180 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
181 | ||
182 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
183 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
184 | MODULE_LICENSE("GPL"); |