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13#include <linux/cpufreq.h>
14#include <linux/module.h>
15#include <linux/err.h>
16#include <linux/sched.h>
17#include <linux/delay.h>
18#include <linux/platform_device.h>
19
20#include <asm/clock.h>
21
22#include <asm/mach-loongson/loongson.h>
23
24static uint nowait;
25
26static struct clk *cpuclk;
27
28static void (*saved_cpu_wait) (void);
29
30static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
31 unsigned long val, void *data);
32
33static struct notifier_block loongson2_cpufreq_notifier_block = {
34 .notifier_call = loongson2_cpu_freq_notifier
35};
36
37static 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
46static unsigned int loongson2_cpufreq_get(unsigned int cpu)
47{
48 return clk_get_rate(cpuclk);
49}
50
51
52
53
54static 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;
68 set_cpus_allowed_ptr(current, cpumask_of(cpu));
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
92 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
93
94 set_cpus_allowed_ptr(current, &cpus_allowed);
95
96
97 clk_set_rate(cpuclk, freq);
98
99
100 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
101
102 pr_debug("cpufreq: set frequency %u kHz\n", freq);
103
104 return 0;
105}
106
107static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
108{
109 int i;
110 unsigned long rate;
111 int ret;
112
113 if (!cpu_online(policy->cpu))
114 return -ENODEV;
115
116 cpuclk = clk_get(NULL, "cpu_clk");
117 if (IS_ERR(cpuclk)) {
118 printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
119 return PTR_ERR(cpuclk);
120 }
121
122 rate = cpu_clock_freq / 1000;
123 if (!rate) {
124 clk_put(cpuclk);
125 return -EINVAL;
126 }
127 ret = clk_set_rate(cpuclk, rate);
128 if (ret) {
129 clk_put(cpuclk);
130 return ret;
131 }
132
133
134 for (i = 2;
135 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
136 i++)
137 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
138
139 policy->cur = loongson2_cpufreq_get(policy->cpu);
140
141 cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
142 policy->cpu);
143
144 return cpufreq_frequency_table_cpuinfo(policy,
145 &loongson2_clockmod_table[0]);
146}
147
148static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
149{
150 return cpufreq_frequency_table_verify(policy,
151 &loongson2_clockmod_table[0]);
152}
153
154static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
155{
156 clk_put(cpuclk);
157 return 0;
158}
159
160static struct freq_attr *loongson2_table_attr[] = {
161 &cpufreq_freq_attr_scaling_available_freqs,
162 NULL,
163};
164
165static struct cpufreq_driver loongson2_cpufreq_driver = {
166 .owner = THIS_MODULE,
167 .name = "loongson2",
168 .init = loongson2_cpufreq_cpu_init,
169 .verify = loongson2_cpufreq_verify,
170 .target = loongson2_cpufreq_target,
171 .get = loongson2_cpufreq_get,
172 .exit = loongson2_cpufreq_exit,
173 .attr = loongson2_table_attr,
174};
175
176static struct platform_device_id platform_device_ids[] = {
177 {
178 .name = "loongson2_cpufreq",
179 },
180 {}
181};
182
183MODULE_DEVICE_TABLE(platform, platform_device_ids);
184
185static struct platform_driver platform_driver = {
186 .driver = {
187 .name = "loongson2_cpufreq",
188 .owner = THIS_MODULE,
189 },
190 .id_table = platform_device_ids,
191};
192
193
194
195
196
197
198static DEFINE_SPINLOCK(loongson2_wait_lock);
199
200static void loongson2_cpu_wait(void)
201{
202 unsigned long flags;
203 u32 cpu_freq;
204
205 spin_lock_irqsave(&loongson2_wait_lock, flags);
206 cpu_freq = LOONGSON_CHIPCFG0;
207 LOONGSON_CHIPCFG0 &= ~0x7;
208 LOONGSON_CHIPCFG0 = cpu_freq;
209 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
210}
211
212static int __init cpufreq_init(void)
213{
214 int ret;
215
216
217 ret = platform_driver_register(&platform_driver);
218 if (ret)
219 return ret;
220
221 pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
222
223 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
224 CPUFREQ_TRANSITION_NOTIFIER);
225
226 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
227
228 if (!ret && !nowait) {
229 saved_cpu_wait = cpu_wait;
230 cpu_wait = loongson2_cpu_wait;
231 }
232
233 return ret;
234}
235
236static void __exit cpufreq_exit(void)
237{
238 if (!nowait && saved_cpu_wait)
239 cpu_wait = saved_cpu_wait;
240 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
241 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
242 CPUFREQ_TRANSITION_NOTIFIER);
243
244 platform_driver_unregister(&platform_driver);
245}
246
247module_init(cpufreq_init);
248module_exit(cpufreq_exit);
249
250module_param(nowait, uint, 0644);
251MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
252
253MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
254MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
255MODULE_LICENSE("GPL");
256
