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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> | |
21 | ||
95cf1468 | 22 | #include <asm/mach-loongson/loongson.h> |
f8ede0f7 WZ |
23 | |
24 | static uint nowait; | |
25 | ||
26 | static struct clk *cpuclk; | |
27 | ||
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 | ||
46 | static unsigned int loongson2_cpufreq_get(unsigned int cpu) | |
47 | { | |
48 | return clk_get_rate(cpuclk); | |
49 | } | |
50 | ||
51 | /* | |
52 | * Here we notify other drivers of the proposed change and the final change. | |
53 | */ | |
54 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, | |
55 | unsigned int target_freq, | |
56 | unsigned int relation) | |
57 | { | |
58 | unsigned int cpu = policy->cpu; | |
59 | unsigned int newstate = 0; | |
60 | cpumask_t cpus_allowed; | |
61 | struct cpufreq_freqs freqs; | |
62 | unsigned int freq; | |
63 | ||
f8ede0f7 | 64 | cpus_allowed = current->cpus_allowed; |
ed1bbdef | 65 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
f8ede0f7 WZ |
66 | |
67 | if (cpufreq_frequency_table_target | |
68 | (policy, &loongson2_clockmod_table[0], target_freq, relation, | |
69 | &newstate)) | |
70 | return -EINVAL; | |
71 | ||
72 | freq = | |
73 | ((cpu_clock_freq / 1000) * | |
74 | loongson2_clockmod_table[newstate].index) / 8; | |
75 | if (freq < policy->min || freq > policy->max) | |
76 | return -EINVAL; | |
77 | ||
78 | pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); | |
79 | ||
f8ede0f7 WZ |
80 | freqs.old = loongson2_cpufreq_get(cpu); |
81 | freqs.new = freq; | |
82 | freqs.flags = 0; | |
83 | ||
84 | if (freqs.new == freqs.old) | |
85 | return 0; | |
86 | ||
87 | /* notifiers */ | |
b43a7ffb | 88 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
f8ede0f7 | 89 | |
ed1bbdef | 90 | set_cpus_allowed_ptr(current, &cpus_allowed); |
f8ede0f7 WZ |
91 | |
92 | /* setting the cpu frequency */ | |
93 | clk_set_rate(cpuclk, freq); | |
94 | ||
95 | /* notifiers */ | |
b43a7ffb | 96 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
f8ede0f7 WZ |
97 | |
98 | pr_debug("cpufreq: set frequency %u kHz\n", freq); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
103 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
104 | { | |
105 | int i; | |
42913c79 JL |
106 | unsigned long rate; |
107 | int ret; | |
f8ede0f7 | 108 | |
f8ede0f7 WZ |
109 | cpuclk = clk_get(NULL, "cpu_clk"); |
110 | if (IS_ERR(cpuclk)) { | |
111 | printk(KERN_ERR "cpufreq: couldn't get CPU clk\n"); | |
112 | return PTR_ERR(cpuclk); | |
113 | } | |
114 | ||
42913c79 JL |
115 | rate = cpu_clock_freq / 1000; |
116 | if (!rate) { | |
117 | clk_put(cpuclk); | |
f8ede0f7 | 118 | return -EINVAL; |
42913c79 JL |
119 | } |
120 | ret = clk_set_rate(cpuclk, rate); | |
121 | if (ret) { | |
122 | clk_put(cpuclk); | |
123 | return ret; | |
124 | } | |
f8ede0f7 WZ |
125 | |
126 | /* clock table init */ | |
127 | for (i = 2; | |
128 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); | |
129 | i++) | |
42913c79 | 130 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
f8ede0f7 WZ |
131 | |
132 | policy->cur = loongson2_cpufreq_get(policy->cpu); | |
133 | ||
134 | cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0], | |
135 | policy->cpu); | |
136 | ||
137 | return cpufreq_frequency_table_cpuinfo(policy, | |
138 | &loongson2_clockmod_table[0]); | |
139 | } | |
140 | ||
141 | static int loongson2_cpufreq_verify(struct cpufreq_policy *policy) | |
142 | { | |
143 | return cpufreq_frequency_table_verify(policy, | |
144 | &loongson2_clockmod_table[0]); | |
145 | } | |
146 | ||
147 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) | |
148 | { | |
149 | clk_put(cpuclk); | |
150 | return 0; | |
151 | } | |
152 | ||
153 | static struct freq_attr *loongson2_table_attr[] = { | |
154 | &cpufreq_freq_attr_scaling_available_freqs, | |
155 | NULL, | |
156 | }; | |
157 | ||
158 | static struct cpufreq_driver loongson2_cpufreq_driver = { | |
159 | .owner = THIS_MODULE, | |
160 | .name = "loongson2", | |
161 | .init = loongson2_cpufreq_cpu_init, | |
162 | .verify = loongson2_cpufreq_verify, | |
163 | .target = loongson2_cpufreq_target, | |
164 | .get = loongson2_cpufreq_get, | |
165 | .exit = loongson2_cpufreq_exit, | |
166 | .attr = loongson2_table_attr, | |
167 | }; | |
168 | ||
169 | static struct platform_device_id platform_device_ids[] = { | |
170 | { | |
171 | .name = "loongson2_cpufreq", | |
172 | }, | |
173 | {} | |
174 | }; | |
175 | ||
176 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
177 | ||
178 | static struct platform_driver platform_driver = { | |
179 | .driver = { | |
180 | .name = "loongson2_cpufreq", | |
181 | .owner = THIS_MODULE, | |
182 | }, | |
183 | .id_table = platform_device_ids, | |
184 | }; | |
185 | ||
95cf1468 RB |
186 | /* |
187 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
188 | * interrupt disabled context. | |
189 | */ | |
190 | ||
191 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
192 | ||
193 | static void loongson2_cpu_wait(void) | |
194 | { | |
195 | unsigned long flags; | |
196 | u32 cpu_freq; | |
197 | ||
198 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
199 | cpu_freq = LOONGSON_CHIPCFG0; | |
70342287 RB |
200 | LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */ |
201 | LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */ | |
95cf1468 RB |
202 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
203 | } | |
204 | ||
f8ede0f7 WZ |
205 | static int __init cpufreq_init(void) |
206 | { | |
207 | int ret; | |
208 | ||
209 | /* Register platform stuff */ | |
210 | ret = platform_driver_register(&platform_driver); | |
211 | if (ret) | |
212 | return ret; | |
213 | ||
214 | pr_info("cpufreq: Loongson-2F CPU frequency driver.\n"); | |
215 | ||
216 | cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, | |
217 | CPUFREQ_TRANSITION_NOTIFIER); | |
218 | ||
219 | ret = cpufreq_register_driver(&loongson2_cpufreq_driver); | |
220 | ||
221 | if (!ret && !nowait) { | |
222 | saved_cpu_wait = cpu_wait; | |
223 | cpu_wait = loongson2_cpu_wait; | |
224 | } | |
225 | ||
226 | return ret; | |
227 | } | |
228 | ||
229 | static void __exit cpufreq_exit(void) | |
230 | { | |
231 | if (!nowait && saved_cpu_wait) | |
232 | cpu_wait = saved_cpu_wait; | |
233 | cpufreq_unregister_driver(&loongson2_cpufreq_driver); | |
234 | cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, | |
235 | CPUFREQ_TRANSITION_NOTIFIER); | |
236 | ||
237 | platform_driver_unregister(&platform_driver); | |
238 | } | |
239 | ||
240 | module_init(cpufreq_init); | |
241 | module_exit(cpufreq_exit); | |
242 | ||
243 | module_param(nowait, uint, 0644); | |
244 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); | |
245 | ||
246 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); | |
247 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); | |
248 | MODULE_LICENSE("GPL"); |