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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 | ||
27 | static struct clk *cpuclk; | |
28 | ||
29 | static void (*saved_cpu_wait) (void); | |
30 | ||
31 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, | |
32 | unsigned long val, void *data); | |
33 | ||
34 | static struct notifier_block loongson2_cpufreq_notifier_block = { | |
35 | .notifier_call = loongson2_cpu_freq_notifier | |
36 | }; | |
37 | ||
38 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, | |
39 | unsigned long val, void *data) | |
40 | { | |
41 | if (val == CPUFREQ_POSTCHANGE) | |
42 | current_cpu_data.udelay_val = loops_per_jiffy; | |
43 | ||
44 | return 0; | |
45 | } | |
46 | ||
47 | static unsigned int loongson2_cpufreq_get(unsigned int cpu) | |
48 | { | |
49 | return clk_get_rate(cpuclk); | |
50 | } | |
51 | ||
52 | /* | |
53 | * Here we notify other drivers of the proposed change and the final change. | |
54 | */ | |
55 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, | |
9c0ebcf7 | 56 | unsigned int index) |
f8ede0f7 WZ |
57 | { |
58 | unsigned int cpu = policy->cpu; | |
f8ede0f7 | 59 | cpumask_t cpus_allowed; |
f8ede0f7 WZ |
60 | unsigned int freq; |
61 | ||
f8ede0f7 | 62 | cpus_allowed = current->cpus_allowed; |
ed1bbdef | 63 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
f8ede0f7 | 64 | |
f8ede0f7 WZ |
65 | freq = |
66 | ((cpu_clock_freq / 1000) * | |
9c0ebcf7 | 67 | loongson2_clockmod_table[index].driver_data) / 8; |
f8ede0f7 | 68 | |
ed1bbdef | 69 | set_cpus_allowed_ptr(current, &cpus_allowed); |
f8ede0f7 WZ |
70 | |
71 | /* setting the cpu frequency */ | |
72 | clk_set_rate(cpuclk, freq); | |
73 | ||
f8ede0f7 WZ |
74 | return 0; |
75 | } | |
76 | ||
77 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
78 | { | |
79 | int i; | |
42913c79 JL |
80 | unsigned long rate; |
81 | int ret; | |
f8ede0f7 | 82 | |
f8ede0f7 WZ |
83 | cpuclk = clk_get(NULL, "cpu_clk"); |
84 | if (IS_ERR(cpuclk)) { | |
85 | printk(KERN_ERR "cpufreq: couldn't get CPU clk\n"); | |
86 | return PTR_ERR(cpuclk); | |
87 | } | |
88 | ||
42913c79 JL |
89 | rate = cpu_clock_freq / 1000; |
90 | if (!rate) { | |
91 | clk_put(cpuclk); | |
f8ede0f7 | 92 | return -EINVAL; |
42913c79 | 93 | } |
f8ede0f7 WZ |
94 | |
95 | /* clock table init */ | |
96 | for (i = 2; | |
97 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
98 | i++) | |
42913c79 | 99 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 | 100 | |
f54fe64d AK |
101 | ret = clk_set_rate(cpuclk, rate); |
102 | if (ret) { | |
103 | clk_put(cpuclk); | |
104 | return ret; | |
105 | } | |
106 | ||
e0b2da58 | 107 | return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); |
f8ede0f7 WZ |
108 | } |
109 | ||
f8ede0f7 WZ |
110 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
111 | { | |
999fe795 | 112 | cpufreq_frequency_table_put_attr(policy->cpu); |
f8ede0f7 WZ |
113 | clk_put(cpuclk); |
114 | return 0; | |
115 | } | |
116 | ||
f8ede0f7 | 117 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
f8ede0f7 WZ |
118 | .name = "loongson2", |
119 | .init = loongson2_cpufreq_cpu_init, | |
6b0f8d73 | 120 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 121 | .target_index = loongson2_cpufreq_target, |
f8ede0f7 WZ |
122 | .get = loongson2_cpufreq_get, |
123 | .exit = loongson2_cpufreq_exit, | |
6b0f8d73 | 124 | .attr = cpufreq_generic_attr, |
f8ede0f7 WZ |
125 | }; |
126 | ||
127 | static struct platform_device_id platform_device_ids[] = { | |
128 | { | |
129 | .name = "loongson2_cpufreq", | |
130 | }, | |
131 | {} | |
132 | }; | |
133 | ||
134 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
135 | ||
136 | static struct platform_driver platform_driver = { | |
137 | .driver = { | |
138 | .name = "loongson2_cpufreq", | |
139 | .owner = THIS_MODULE, | |
140 | }, | |
141 | .id_table = platform_device_ids, | |
142 | }; | |
143 | ||
95cf1468 RB |
144 | /* |
145 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
146 | * interrupt disabled context. | |
147 | */ | |
148 | ||
149 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
150 | ||
151 | static void loongson2_cpu_wait(void) | |
152 | { | |
153 | unsigned long flags; | |
154 | u32 cpu_freq; | |
155 | ||
156 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
157 | cpu_freq = LOONGSON_CHIPCFG0; | |
70342287 RB |
158 | LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */ |
159 | LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */ | |
95cf1468 | 160 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 161 | local_irq_enable(); |
95cf1468 RB |
162 | } |
163 | ||
f8ede0f7 WZ |
164 | static int __init cpufreq_init(void) |
165 | { | |
166 | int ret; | |
167 | ||
168 | /* Register platform stuff */ | |
169 | ret = platform_driver_register(&platform_driver); | |
170 | if (ret) | |
171 | return ret; | |
172 | ||
173 | pr_info("cpufreq: Loongson-2F CPU frequency driver.\n"); | |
174 | ||
175 | cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, | |
176 | CPUFREQ_TRANSITION_NOTIFIER); | |
177 | ||
178 | ret = cpufreq_register_driver(&loongson2_cpufreq_driver); | |
179 | ||
180 | if (!ret && !nowait) { | |
181 | saved_cpu_wait = cpu_wait; | |
182 | cpu_wait = loongson2_cpu_wait; | |
183 | } | |
184 | ||
185 | return ret; | |
186 | } | |
187 | ||
188 | static void __exit cpufreq_exit(void) | |
189 | { | |
190 | if (!nowait && saved_cpu_wait) | |
191 | cpu_wait = saved_cpu_wait; | |
192 | cpufreq_unregister_driver(&loongson2_cpufreq_driver); | |
193 | cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, | |
194 | CPUFREQ_TRANSITION_NOTIFIER); | |
195 | ||
196 | platform_driver_unregister(&platform_driver); | |
197 | } | |
198 | ||
199 | module_init(cpufreq_init); | |
200 | module_exit(cpufreq_exit); | |
201 | ||
202 | module_param(nowait, uint, 0644); | |
203 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
204 | ||
205 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
206 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
207 | MODULE_LICENSE("GPL"); |