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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 | * | |
6 | * Copyright (C) 2006 - 2008 Lemote Inc. & Insititute 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> | |
bdc92d74 | 21 | #include <asm/idle.h> |
f8ede0f7 | 22 | |
95cf1468 | 23 | #include <asm/mach-loongson/loongson.h> |
f8ede0f7 WZ |
24 | |
25 | static uint nowait; | |
26 | ||
f8ede0f7 WZ |
27 | static void (*saved_cpu_wait) (void); |
28 | ||
29 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, | |
30 | unsigned long val, void *data); | |
31 | ||
32 | static struct notifier_block loongson2_cpufreq_notifier_block = { | |
33 | .notifier_call = loongson2_cpu_freq_notifier | |
34 | }; | |
35 | ||
36 | static 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 | ||
f8ede0f7 WZ |
45 | /* |
46 | * Here we notify other drivers of the proposed change and the final change. | |
47 | */ | |
48 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, | |
9c0ebcf7 | 49 | unsigned int index) |
f8ede0f7 WZ |
50 | { |
51 | unsigned int cpu = policy->cpu; | |
f8ede0f7 | 52 | cpumask_t cpus_allowed; |
f8ede0f7 WZ |
53 | unsigned int freq; |
54 | ||
f8ede0f7 | 55 | cpus_allowed = current->cpus_allowed; |
ed1bbdef | 56 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
f8ede0f7 | 57 | |
f8ede0f7 WZ |
58 | freq = |
59 | ((cpu_clock_freq / 1000) * | |
9c0ebcf7 | 60 | loongson2_clockmod_table[index].driver_data) / 8; |
f8ede0f7 | 61 | |
ed1bbdef | 62 | set_cpus_allowed_ptr(current, &cpus_allowed); |
f8ede0f7 WZ |
63 | |
64 | /* setting the cpu frequency */ | |
8e8acb32 | 65 | clk_set_rate(policy->clk, freq * 1000); |
f8ede0f7 | 66 | |
f8ede0f7 WZ |
67 | return 0; |
68 | } | |
69 | ||
70 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
71 | { | |
05ed6722 | 72 | struct clk *cpuclk; |
f8ede0f7 | 73 | int i; |
42913c79 JL |
74 | unsigned long rate; |
75 | int ret; | |
f8ede0f7 | 76 | |
f8ede0f7 WZ |
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 | ||
42913c79 JL |
83 | rate = cpu_clock_freq / 1000; |
84 | if (!rate) { | |
85 | clk_put(cpuclk); | |
f8ede0f7 | 86 | return -EINVAL; |
42913c79 | 87 | } |
f8ede0f7 WZ |
88 | |
89 | /* clock table init */ | |
90 | for (i = 2; | |
91 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
92 | i++) | |
42913c79 | 93 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 | 94 | |
8e8acb32 | 95 | ret = clk_set_rate(cpuclk, rate * 1000); |
f54fe64d AK |
96 | if (ret) { |
97 | clk_put(cpuclk); | |
98 | return ret; | |
99 | } | |
100 | ||
652ed95d | 101 | policy->clk = cpuclk; |
e0b2da58 | 102 | return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); |
f8ede0f7 WZ |
103 | } |
104 | ||
f8ede0f7 WZ |
105 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
106 | { | |
652ed95d | 107 | clk_put(policy->clk); |
f8ede0f7 WZ |
108 | return 0; |
109 | } | |
110 | ||
f8ede0f7 | 111 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
f8ede0f7 WZ |
112 | .name = "loongson2", |
113 | .init = loongson2_cpufreq_cpu_init, | |
6b0f8d73 | 114 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 115 | .target_index = loongson2_cpufreq_target, |
652ed95d | 116 | .get = cpufreq_generic_get, |
f8ede0f7 | 117 | .exit = loongson2_cpufreq_exit, |
6b0f8d73 | 118 | .attr = cpufreq_generic_attr, |
f8ede0f7 WZ |
119 | }; |
120 | ||
121 | static struct platform_device_id platform_device_ids[] = { | |
122 | { | |
123 | .name = "loongson2_cpufreq", | |
124 | }, | |
125 | {} | |
126 | }; | |
127 | ||
128 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
129 | ||
130 | static struct platform_driver platform_driver = { | |
131 | .driver = { | |
132 | .name = "loongson2_cpufreq", | |
f8ede0f7 WZ |
133 | }, |
134 | .id_table = platform_device_ids, | |
135 | }; | |
136 | ||
95cf1468 RB |
137 | /* |
138 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
139 | * interrupt disabled context. | |
140 | */ | |
141 | ||
142 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
143 | ||
144 | static void loongson2_cpu_wait(void) | |
145 | { | |
146 | unsigned long flags; | |
147 | u32 cpu_freq; | |
148 | ||
149 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
140e39c1 HC |
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 */ | |
95cf1468 | 153 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 154 | local_irq_enable(); |
95cf1468 RB |
155 | } |
156 | ||
f8ede0f7 WZ |
157 | static 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 | ||
181 | static 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 | ||
192 | module_init(cpufreq_init); | |
193 | module_exit(cpufreq_exit); | |
194 | ||
195 | module_param(nowait, uint, 0644); | |
196 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
197 | ||
198 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
199 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
200 | MODULE_LICENSE("GPL"); |