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Wu Zhangjinf8ede0f2009-11-17 01:32:59 +08001/*
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>
Ralf Baechlebdc92d742013-05-21 16:59:19 +020021#include <asm/idle.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080022
Ralf Baechle95cf1462012-08-01 17:15:32 +020023#include <asm/mach-loongson/loongson.h>
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080024
25static uint nowait;
26
27static struct clk *cpuclk;
28
29static void (*saved_cpu_wait) (void);
30
31static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
32 unsigned long val, void *data);
33
34static struct notifier_block loongson2_cpufreq_notifier_block = {
35 .notifier_call = loongson2_cpu_freq_notifier
36};
37
38static 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
47static 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 */
55static 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
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080065 cpus_allowed = current->cpus_allowed;
Julia Lawalled1bbde2010-03-26 23:03:07 +010066 set_cpus_allowed_ptr(current, cpumask_of(cpu));
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080067
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) *
Viresh Kumar50701582013-03-30 16:25:15 +053075 loongson2_clockmod_table[newstate].driver_data) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080076 if (freq < policy->min || freq > policy->max)
77 return -EINVAL;
78
79 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
80
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080081 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 */
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053089 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080090
Julia Lawalled1bbde2010-03-26 23:03:07 +010091 set_cpus_allowed_ptr(current, &cpus_allowed);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080092
93 /* setting the cpu frequency */
94 clk_set_rate(cpuclk, freq);
95
96 /* notifiers */
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053097 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +080098
99 pr_debug("cpufreq: set frequency %u kHz\n", freq);
100
101 return 0;
102}
103
104static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
105{
106 int i;
Julia Lawall42913c72013-01-03 09:34:20 +0000107 unsigned long rate;
108 int ret;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800109
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800110 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
Julia Lawall42913c72013-01-03 09:34:20 +0000116 rate = cpu_clock_freq / 1000;
117 if (!rate) {
118 clk_put(cpuclk);
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800119 return -EINVAL;
Julia Lawall42913c72013-01-03 09:34:20 +0000120 }
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800121
122 /* clock table init */
123 for (i = 2;
124 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
125 i++)
Julia Lawall42913c72013-01-03 09:34:20 +0000126 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800127
Aaro Koskinenf54fe642013-08-05 21:27:12 +0300128 ret = clk_set_rate(cpuclk, rate);
129 if (ret) {
130 clk_put(cpuclk);
131 return ret;
132 }
133
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800134 policy->cur = loongson2_cpufreq_get(policy->cpu);
135
136 cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
137 policy->cpu);
138
139 return cpufreq_frequency_table_cpuinfo(policy,
140 &loongson2_clockmod_table[0]);
141}
142
143static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
144{
145 return cpufreq_frequency_table_verify(policy,
146 &loongson2_clockmod_table[0]);
147}
148
149static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
150{
151 clk_put(cpuclk);
152 return 0;
153}
154
155static struct freq_attr *loongson2_table_attr[] = {
156 &cpufreq_freq_attr_scaling_available_freqs,
157 NULL,
158};
159
160static struct cpufreq_driver loongson2_cpufreq_driver = {
161 .owner = THIS_MODULE,
162 .name = "loongson2",
163 .init = loongson2_cpufreq_cpu_init,
164 .verify = loongson2_cpufreq_verify,
165 .target = loongson2_cpufreq_target,
166 .get = loongson2_cpufreq_get,
167 .exit = loongson2_cpufreq_exit,
168 .attr = loongson2_table_attr,
169};
170
171static struct platform_device_id platform_device_ids[] = {
172 {
173 .name = "loongson2_cpufreq",
174 },
175 {}
176};
177
178MODULE_DEVICE_TABLE(platform, platform_device_ids);
179
180static struct platform_driver platform_driver = {
181 .driver = {
182 .name = "loongson2_cpufreq",
183 .owner = THIS_MODULE,
184 },
185 .id_table = platform_device_ids,
186};
187
Ralf Baechle95cf1462012-08-01 17:15:32 +0200188/*
189 * This is the simple version of Loongson-2 wait, Maybe we need do this in
190 * interrupt disabled context.
191 */
192
193static DEFINE_SPINLOCK(loongson2_wait_lock);
194
195static void loongson2_cpu_wait(void)
196{
197 unsigned long flags;
198 u32 cpu_freq;
199
200 spin_lock_irqsave(&loongson2_wait_lock, flags);
201 cpu_freq = LOONGSON_CHIPCFG0;
Ralf Baechle70342282013-01-22 12:59:30 +0100202 LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */
203 LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */
Ralf Baechle95cf1462012-08-01 17:15:32 +0200204 spin_unlock_irqrestore(&loongson2_wait_lock, flags);
Ralf Baechlefb40bc32013-05-21 14:05:27 +0200205 local_irq_enable();
Ralf Baechle95cf1462012-08-01 17:15:32 +0200206}
207
Wu Zhangjinf8ede0f2009-11-17 01:32:59 +0800208static int __init cpufreq_init(void)
209{
210 int ret;
211
212 /* Register platform stuff */
213 ret = platform_driver_register(&platform_driver);
214 if (ret)
215 return ret;
216
217 pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
218
219 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
220 CPUFREQ_TRANSITION_NOTIFIER);
221
222 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
223
224 if (!ret && !nowait) {
225 saved_cpu_wait = cpu_wait;
226 cpu_wait = loongson2_cpu_wait;
227 }
228
229 return ret;
230}
231
232static void __exit cpufreq_exit(void)
233{
234 if (!nowait && saved_cpu_wait)
235 cpu_wait = saved_cpu_wait;
236 cpufreq_unregister_driver(&loongson2_cpufreq_driver);
237 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
238 CPUFREQ_TRANSITION_NOTIFIER);
239
240 platform_driver_unregister(&platform_driver);
241}
242
243module_init(cpufreq_init);
244module_exit(cpufreq_exit);
245
246module_param(nowait, uint, 0644);
247MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
248
249MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
250MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
251MODULE_LICENSE("GPL");