Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6-microblaze.git] / drivers / cpufreq / loongson2_cpufreq.c
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. & Institute 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
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16 #include <linux/cpufreq.h>
17 #include <linux/module.h>
18 #include <linux/err.h>
19 #include <linux/sched.h>        /* set_cpus_allowed() */
20 #include <linux/delay.h>
21 #include <linux/platform_device.h>
22
23 #include <asm/clock.h>
24 #include <asm/idle.h>
25
26 #include <asm/mach-loongson64/loongson.h>
27
28 static uint nowait;
29
30 static void (*saved_cpu_wait) (void);
31
32 static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
33                                         unsigned long val, void *data);
34
35 static struct notifier_block loongson2_cpufreq_notifier_block = {
36         .notifier_call = loongson2_cpu_freq_notifier
37 };
38
39 static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
40                                         unsigned long val, void *data)
41 {
42         if (val == CPUFREQ_POSTCHANGE)
43                 current_cpu_data.udelay_val = loops_per_jiffy;
44
45         return 0;
46 }
47
48 /*
49  * Here we notify other drivers of the proposed change and the final change.
50  */
51 static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
52                                      unsigned int index)
53 {
54         unsigned int cpu = policy->cpu;
55         cpumask_t cpus_allowed;
56         unsigned int freq;
57
58         cpus_allowed = current->cpus_allowed;
59         set_cpus_allowed_ptr(current, cpumask_of(cpu));
60
61         freq =
62             ((cpu_clock_freq / 1000) *
63              loongson2_clockmod_table[index].driver_data) / 8;
64
65         set_cpus_allowed_ptr(current, &cpus_allowed);
66
67         /* setting the cpu frequency */
68         clk_set_rate(policy->clk, freq * 1000);
69
70         return 0;
71 }
72
73 static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
74 {
75         struct clk *cpuclk;
76         int i;
77         unsigned long rate;
78         int ret;
79
80         cpuclk = clk_get(NULL, "cpu_clk");
81         if (IS_ERR(cpuclk)) {
82                 pr_err("couldn't get CPU clk\n");
83                 return PTR_ERR(cpuclk);
84         }
85
86         rate = cpu_clock_freq / 1000;
87         if (!rate) {
88                 clk_put(cpuclk);
89                 return -EINVAL;
90         }
91
92         /* clock table init */
93         for (i = 2;
94              (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
95              i++)
96                 loongson2_clockmod_table[i].frequency = (rate * i) / 8;
97
98         ret = clk_set_rate(cpuclk, rate * 1000);
99         if (ret) {
100                 clk_put(cpuclk);
101                 return ret;
102         }
103
104         policy->clk = cpuclk;
105         return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
106 }
107
108 static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
109 {
110         clk_put(policy->clk);
111         return 0;
112 }
113
114 static struct cpufreq_driver loongson2_cpufreq_driver = {
115         .name = "loongson2",
116         .init = loongson2_cpufreq_cpu_init,
117         .verify = cpufreq_generic_frequency_table_verify,
118         .target_index = loongson2_cpufreq_target,
119         .get = cpufreq_generic_get,
120         .exit = loongson2_cpufreq_exit,
121         .attr = cpufreq_generic_attr,
122 };
123
124 static struct platform_device_id platform_device_ids[] = {
125         {
126                 .name = "loongson2_cpufreq",
127         },
128         {}
129 };
130
131 MODULE_DEVICE_TABLE(platform, platform_device_ids);
132
133 static struct platform_driver platform_driver = {
134         .driver = {
135                 .name = "loongson2_cpufreq",
136         },
137         .id_table = platform_device_ids,
138 };
139
140 /*
141  * This is the simple version of Loongson-2 wait, Maybe we need do this in
142  * interrupt disabled context.
143  */
144
145 static DEFINE_SPINLOCK(loongson2_wait_lock);
146
147 static void loongson2_cpu_wait(void)
148 {
149         unsigned long flags;
150         u32 cpu_freq;
151
152         spin_lock_irqsave(&loongson2_wait_lock, flags);
153         cpu_freq = LOONGSON_CHIPCFG(0);
154         LOONGSON_CHIPCFG(0) &= ~0x7;    /* Put CPU into wait mode */
155         LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
156         spin_unlock_irqrestore(&loongson2_wait_lock, flags);
157         local_irq_enable();
158 }
159
160 static int __init cpufreq_init(void)
161 {
162         int ret;
163
164         /* Register platform stuff */
165         ret = platform_driver_register(&platform_driver);
166         if (ret)
167                 return ret;
168
169         pr_info("Loongson-2F CPU frequency driver\n");
170
171         cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
172                                   CPUFREQ_TRANSITION_NOTIFIER);
173
174         ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
175
176         if (!ret && !nowait) {
177                 saved_cpu_wait = cpu_wait;
178                 cpu_wait = loongson2_cpu_wait;
179         }
180
181         return ret;
182 }
183
184 static void __exit cpufreq_exit(void)
185 {
186         if (!nowait && saved_cpu_wait)
187                 cpu_wait = saved_cpu_wait;
188         cpufreq_unregister_driver(&loongson2_cpufreq_driver);
189         cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
190                                     CPUFREQ_TRANSITION_NOTIFIER);
191
192         platform_driver_unregister(&platform_driver);
193 }
194
195 module_init(cpufreq_init);
196 module_exit(cpufreq_exit);
197
198 module_param(nowait, uint, 0644);
199 MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
200
201 MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
202 MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
203 MODULE_LICENSE("GPL");