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