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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> | |
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> | |
bdc92d74 | 24 | #include <asm/idle.h> |
f8ede0f7 | 25 | |
71e2f4dd | 26 | #include <asm/mach-loongson2ef/loongson.h> |
f8ede0f7 WZ |
27 | |
28 | static uint nowait; | |
29 | ||
f8ede0f7 WZ |
30 | static void (*saved_cpu_wait) (void); |
31 | ||
32 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, | |
33 | unsigned long val, void *data); | |
34 | ||
35 | static struct notifier_block loongson2_cpufreq_notifier_block = { | |
36 | .notifier_call = loongson2_cpu_freq_notifier | |
37 | }; | |
38 | ||
39 | static 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 | ||
f8ede0f7 WZ |
48 | /* |
49 | * Here we notify other drivers of the proposed change and the final change. | |
50 | */ | |
51 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, | |
9c0ebcf7 | 52 | unsigned int index) |
f8ede0f7 | 53 | { |
f8ede0f7 WZ |
54 | unsigned int freq; |
55 | ||
f8ede0f7 WZ |
56 | freq = |
57 | ((cpu_clock_freq / 1000) * | |
9c0ebcf7 | 58 | loongson2_clockmod_table[index].driver_data) / 8; |
f8ede0f7 | 59 | |
f8ede0f7 | 60 | /* setting the cpu frequency */ |
8e8acb32 | 61 | clk_set_rate(policy->clk, freq * 1000); |
f8ede0f7 | 62 | |
f8ede0f7 WZ |
63 | return 0; |
64 | } | |
65 | ||
66 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
67 | { | |
05ed6722 | 68 | struct clk *cpuclk; |
f8ede0f7 | 69 | int i; |
42913c79 JL |
70 | unsigned long rate; |
71 | int ret; | |
f8ede0f7 | 72 | |
f8ede0f7 WZ |
73 | cpuclk = clk_get(NULL, "cpu_clk"); |
74 | if (IS_ERR(cpuclk)) { | |
1c5864e2 | 75 | pr_err("couldn't get CPU clk\n"); |
f8ede0f7 WZ |
76 | return PTR_ERR(cpuclk); |
77 | } | |
78 | ||
42913c79 JL |
79 | rate = cpu_clock_freq / 1000; |
80 | if (!rate) { | |
81 | clk_put(cpuclk); | |
f8ede0f7 | 82 | return -EINVAL; |
42913c79 | 83 | } |
f8ede0f7 WZ |
84 | |
85 | /* clock table init */ | |
86 | for (i = 2; | |
87 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
88 | i++) | |
42913c79 | 89 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 | 90 | |
8e8acb32 | 91 | ret = clk_set_rate(cpuclk, rate * 1000); |
f54fe64d AK |
92 | if (ret) { |
93 | clk_put(cpuclk); | |
94 | return ret; | |
95 | } | |
96 | ||
652ed95d | 97 | policy->clk = cpuclk; |
c4dcc8a1 VK |
98 | cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); |
99 | return 0; | |
f8ede0f7 WZ |
100 | } |
101 | ||
f8ede0f7 WZ |
102 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
103 | { | |
652ed95d | 104 | clk_put(policy->clk); |
f8ede0f7 WZ |
105 | return 0; |
106 | } | |
107 | ||
f8ede0f7 | 108 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
f8ede0f7 WZ |
109 | .name = "loongson2", |
110 | .init = loongson2_cpufreq_cpu_init, | |
6b0f8d73 | 111 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 112 | .target_index = loongson2_cpufreq_target, |
652ed95d | 113 | .get = cpufreq_generic_get, |
f8ede0f7 | 114 | .exit = loongson2_cpufreq_exit, |
6b0f8d73 | 115 | .attr = cpufreq_generic_attr, |
f8ede0f7 WZ |
116 | }; |
117 | ||
a804d510 | 118 | static const struct platform_device_id platform_device_ids[] = { |
f8ede0f7 WZ |
119 | { |
120 | .name = "loongson2_cpufreq", | |
121 | }, | |
122 | {} | |
123 | }; | |
124 | ||
125 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
126 | ||
127 | static struct platform_driver platform_driver = { | |
128 | .driver = { | |
129 | .name = "loongson2_cpufreq", | |
f8ede0f7 WZ |
130 | }, |
131 | .id_table = platform_device_ids, | |
132 | }; | |
133 | ||
95cf1468 RB |
134 | /* |
135 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
136 | * interrupt disabled context. | |
137 | */ | |
138 | ||
139 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
140 | ||
141 | static void loongson2_cpu_wait(void) | |
142 | { | |
143 | unsigned long flags; | |
144 | u32 cpu_freq; | |
145 | ||
146 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
1250c1a5 AO |
147 | cpu_freq = readl(LOONGSON_CHIPCFG); |
148 | /* Put CPU into wait mode */ | |
149 | writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG); | |
150 | /* Restore CPU state */ | |
151 | writel(cpu_freq, LOONGSON_CHIPCFG); | |
95cf1468 | 152 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 153 | local_irq_enable(); |
95cf1468 RB |
154 | } |
155 | ||
f8ede0f7 WZ |
156 | static int __init cpufreq_init(void) |
157 | { | |
158 | int ret; | |
159 | ||
160 | /* Register platform stuff */ | |
161 | ret = platform_driver_register(&platform_driver); | |
162 | if (ret) | |
163 | return ret; | |
164 | ||
1c5864e2 | 165 | pr_info("Loongson-2F CPU frequency driver\n"); |
f8ede0f7 WZ |
166 | |
167 | cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, | |
168 | CPUFREQ_TRANSITION_NOTIFIER); | |
169 | ||
170 | ret = cpufreq_register_driver(&loongson2_cpufreq_driver); | |
171 | ||
172 | if (!ret && !nowait) { | |
173 | saved_cpu_wait = cpu_wait; | |
174 | cpu_wait = loongson2_cpu_wait; | |
175 | } | |
176 | ||
177 | return ret; | |
178 | } | |
179 | ||
180 | static void __exit cpufreq_exit(void) | |
181 | { | |
182 | if (!nowait && saved_cpu_wait) | |
183 | cpu_wait = saved_cpu_wait; | |
184 | cpufreq_unregister_driver(&loongson2_cpufreq_driver); | |
185 | cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, | |
186 | CPUFREQ_TRANSITION_NOTIFIER); | |
187 | ||
188 | platform_driver_unregister(&platform_driver); | |
189 | } | |
190 | ||
191 | module_init(cpufreq_init); | |
192 | module_exit(cpufreq_exit); | |
193 | ||
194 | module_param(nowait, uint, 0644); | |
195 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
196 | ||
197 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
198 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
199 | MODULE_LICENSE("GPL"); |