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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, | |
56 | unsigned int target_freq, | |
57 | unsigned int relation) | |
58 | { | |
59 | unsigned int cpu = policy->cpu; | |
60 | unsigned int newstate = 0; | |
61 | cpumask_t cpus_allowed; | |
62 | struct cpufreq_freqs freqs; | |
63 | unsigned int freq; | |
64 | ||
f8ede0f7 | 65 | cpus_allowed = current->cpus_allowed; |
ed1bbdef | 66 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
f8ede0f7 WZ |
67 | |
68 | if (cpufreq_frequency_table_target | |
69 | (policy, &loongson2_clockmod_table[0], target_freq, relation, | |
70 | &newstate)) | |
71 | return -EINVAL; | |
72 | ||
73 | freq = | |
74 | ((cpu_clock_freq / 1000) * | |
50701588 | 75 | loongson2_clockmod_table[newstate].driver_data) / 8; |
f8ede0f7 WZ |
76 | if (freq < policy->min || freq > policy->max) |
77 | return -EINVAL; | |
78 | ||
79 | pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); | |
80 | ||
f8ede0f7 WZ |
81 | freqs.old = loongson2_cpufreq_get(cpu); |
82 | freqs.new = freq; | |
83 | freqs.flags = 0; | |
84 | ||
85 | if (freqs.new == freqs.old) | |
86 | return 0; | |
87 | ||
88 | /* notifiers */ | |
b43a7ffb | 89 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
f8ede0f7 | 90 | |
ed1bbdef | 91 | set_cpus_allowed_ptr(current, &cpus_allowed); |
f8ede0f7 WZ |
92 | |
93 | /* setting the cpu frequency */ | |
94 | clk_set_rate(cpuclk, freq); | |
95 | ||
96 | /* notifiers */ | |
b43a7ffb | 97 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
f8ede0f7 WZ |
98 | |
99 | pr_debug("cpufreq: set frequency %u kHz\n", freq); | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
105 | { | |
106 | int i; | |
42913c79 JL |
107 | unsigned long rate; |
108 | int ret; | |
f8ede0f7 | 109 | |
f8ede0f7 WZ |
110 | cpuclk = clk_get(NULL, "cpu_clk"); |
111 | if (IS_ERR(cpuclk)) { | |
112 | printk(KERN_ERR "cpufreq: couldn't get CPU clk\n"); | |
113 | return PTR_ERR(cpuclk); | |
114 | } | |
115 | ||
42913c79 JL |
116 | rate = cpu_clock_freq / 1000; |
117 | if (!rate) { | |
118 | clk_put(cpuclk); | |
f8ede0f7 | 119 | return -EINVAL; |
42913c79 | 120 | } |
f8ede0f7 WZ |
121 | |
122 | /* clock table init */ | |
123 | for (i = 2; | |
124 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
125 | i++) | |
42913c79 | 126 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 | 127 | |
f54fe64d AK |
128 | ret = clk_set_rate(cpuclk, rate); |
129 | if (ret) { | |
130 | clk_put(cpuclk); | |
131 | return ret; | |
132 | } | |
133 | ||
e0b2da58 | 134 | return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); |
f8ede0f7 WZ |
135 | } |
136 | ||
f8ede0f7 WZ |
137 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
138 | { | |
999fe795 | 139 | cpufreq_frequency_table_put_attr(policy->cpu); |
f8ede0f7 WZ |
140 | clk_put(cpuclk); |
141 | return 0; | |
142 | } | |
143 | ||
f8ede0f7 | 144 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
f8ede0f7 WZ |
145 | .name = "loongson2", |
146 | .init = loongson2_cpufreq_cpu_init, | |
6b0f8d73 | 147 | .verify = cpufreq_generic_frequency_table_verify, |
f8ede0f7 WZ |
148 | .target = loongson2_cpufreq_target, |
149 | .get = loongson2_cpufreq_get, | |
150 | .exit = loongson2_cpufreq_exit, | |
6b0f8d73 | 151 | .attr = cpufreq_generic_attr, |
f8ede0f7 WZ |
152 | }; |
153 | ||
154 | static struct platform_device_id platform_device_ids[] = { | |
155 | { | |
156 | .name = "loongson2_cpufreq", | |
157 | }, | |
158 | {} | |
159 | }; | |
160 | ||
161 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
162 | ||
163 | static struct platform_driver platform_driver = { | |
164 | .driver = { | |
165 | .name = "loongson2_cpufreq", | |
166 | .owner = THIS_MODULE, | |
167 | }, | |
168 | .id_table = platform_device_ids, | |
169 | }; | |
170 | ||
95cf1468 RB |
171 | /* |
172 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
173 | * interrupt disabled context. | |
174 | */ | |
175 | ||
176 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
177 | ||
178 | static void loongson2_cpu_wait(void) | |
179 | { | |
180 | unsigned long flags; | |
181 | u32 cpu_freq; | |
182 | ||
183 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
184 | cpu_freq = LOONGSON_CHIPCFG0; | |
70342287 RB |
185 | LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */ |
186 | LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */ | |
95cf1468 | 187 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 188 | local_irq_enable(); |
95cf1468 RB |
189 | } |
190 | ||
f8ede0f7 WZ |
191 | static int __init cpufreq_init(void) |
192 | { | |
193 | int ret; | |
194 | ||
195 | /* Register platform stuff */ | |
196 | ret = platform_driver_register(&platform_driver); | |
197 | if (ret) | |
198 | return ret; | |
199 | ||
200 | pr_info("cpufreq: Loongson-2F CPU frequency driver.\n"); | |
201 | ||
202 | cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, | |
203 | CPUFREQ_TRANSITION_NOTIFIER); | |
204 | ||
205 | ret = cpufreq_register_driver(&loongson2_cpufreq_driver); | |
206 | ||
207 | if (!ret && !nowait) { | |
208 | saved_cpu_wait = cpu_wait; | |
209 | cpu_wait = loongson2_cpu_wait; | |
210 | } | |
211 | ||
212 | return ret; | |
213 | } | |
214 | ||
215 | static void __exit cpufreq_exit(void) | |
216 | { | |
217 | if (!nowait && saved_cpu_wait) | |
218 | cpu_wait = saved_cpu_wait; | |
219 | cpufreq_unregister_driver(&loongson2_cpufreq_driver); | |
220 | cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, | |
221 | CPUFREQ_TRANSITION_NOTIFIER); | |
222 | ||
223 | platform_driver_unregister(&platform_driver); | |
224 | } | |
225 | ||
226 | module_init(cpufreq_init); | |
227 | module_exit(cpufreq_exit); | |
228 | ||
229 | module_param(nowait, uint, 0644); | |
230 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
231 | ||
232 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
233 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
234 | MODULE_LICENSE("GPL"); |