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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 | ||
f8ede0f7 WZ |
134 | policy->cur = loongson2_cpufreq_get(policy->cpu); |
135 | ||
f7112352 | 136 | return cpufreq_table_validate_and_show(policy, |
f8ede0f7 WZ |
137 | &loongson2_clockmod_table[0]); |
138 | } | |
139 | ||
140 | static int loongson2_cpufreq_verify(struct cpufreq_policy *policy) | |
141 | { | |
142 | return cpufreq_frequency_table_verify(policy, | |
143 | &loongson2_clockmod_table[0]); | |
144 | } | |
145 | ||
146 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) | |
147 | { | |
999fe795 | 148 | cpufreq_frequency_table_put_attr(policy->cpu); |
f8ede0f7 WZ |
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 = { | |
f8ede0f7 WZ |
159 | .name = "loongson2", |
160 | .init = loongson2_cpufreq_cpu_init, | |
161 | .verify = loongson2_cpufreq_verify, | |
162 | .target = loongson2_cpufreq_target, | |
163 | .get = loongson2_cpufreq_get, | |
164 | .exit = loongson2_cpufreq_exit, | |
165 | .attr = loongson2_table_attr, | |
166 | }; | |
167 | ||
168 | static struct platform_device_id platform_device_ids[] = { | |
169 | { | |
170 | .name = "loongson2_cpufreq", | |
171 | }, | |
172 | {} | |
173 | }; | |
174 | ||
175 | MODULE_DEVICE_TABLE(platform, platform_device_ids); | |
176 | ||
177 | static struct platform_driver platform_driver = { | |
178 | .driver = { | |
179 | .name = "loongson2_cpufreq", | |
180 | .owner = THIS_MODULE, | |
181 | }, | |
182 | .id_table = platform_device_ids, | |
183 | }; | |
184 | ||
95cf1468 RB |
185 | /* |
186 | * This is the simple version of Loongson-2 wait, Maybe we need do this in | |
187 | * interrupt disabled context. | |
188 | */ | |
189 | ||
190 | static DEFINE_SPINLOCK(loongson2_wait_lock); | |
191 | ||
192 | static void loongson2_cpu_wait(void) | |
193 | { | |
194 | unsigned long flags; | |
195 | u32 cpu_freq; | |
196 | ||
197 | spin_lock_irqsave(&loongson2_wait_lock, flags); | |
198 | cpu_freq = LOONGSON_CHIPCFG0; | |
70342287 RB |
199 | LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */ |
200 | LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */ | |
95cf1468 | 201 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
fb40bc3e | 202 | local_irq_enable(); |
95cf1468 RB |
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"); |