2 * Cpufreq driver for the loongson-2 processors
4 * The 2E revision of loongson processor not support this feature.
6 * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
7 * Author: Yanhua, yanh@lemote.com
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
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/cpufreq.h>
17 #include <linux/module.h>
18 #include <linux/err.h>
19 #include <linux/delay.h>
20 #include <linux/platform_device.h>
24 #include <asm/mach-loongson2ef/loongson.h>
28 static void (*saved_cpu_wait
) (void);
30 static int loongson2_cpu_freq_notifier(struct notifier_block
*nb
,
31 unsigned long val
, void *data
);
33 static struct notifier_block loongson2_cpufreq_notifier_block
= {
34 .notifier_call
= loongson2_cpu_freq_notifier
37 static int loongson2_cpu_freq_notifier(struct notifier_block
*nb
,
38 unsigned long val
, void *data
)
40 if (val
== CPUFREQ_POSTCHANGE
)
41 current_cpu_data
.udelay_val
= loops_per_jiffy
;
47 * Here we notify other drivers of the proposed change and the final change.
49 static int loongson2_cpufreq_target(struct cpufreq_policy
*policy
,
55 ((cpu_clock_freq
/ 1000) *
56 loongson2_clockmod_table
[index
].driver_data
) / 8;
58 /* setting the cpu frequency */
59 loongson2_cpu_set_rate(freq
);
64 static int loongson2_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
70 rate
= cpu_clock_freq
/ 1000;
74 /* clock table init */
76 (loongson2_clockmod_table
[i
].frequency
!= CPUFREQ_TABLE_END
);
78 loongson2_clockmod_table
[i
].frequency
= (rate
* i
) / 8;
80 ret
= loongson2_cpu_set_rate(rate
);
84 cpufreq_generic_init(policy
, &loongson2_clockmod_table
[0], 0);
88 static int loongson2_cpufreq_exit(struct cpufreq_policy
*policy
)
93 static struct cpufreq_driver loongson2_cpufreq_driver
= {
95 .init
= loongson2_cpufreq_cpu_init
,
96 .verify
= cpufreq_generic_frequency_table_verify
,
97 .target_index
= loongson2_cpufreq_target
,
98 .get
= cpufreq_generic_get
,
99 .exit
= loongson2_cpufreq_exit
,
100 .attr
= cpufreq_generic_attr
,
103 static const struct platform_device_id platform_device_ids
[] = {
105 .name
= "loongson2_cpufreq",
110 MODULE_DEVICE_TABLE(platform
, platform_device_ids
);
112 static struct platform_driver platform_driver
= {
114 .name
= "loongson2_cpufreq",
116 .id_table
= platform_device_ids
,
120 * This is the simple version of Loongson-2 wait, Maybe we need do this in
121 * interrupt disabled context.
124 static DEFINE_SPINLOCK(loongson2_wait_lock
);
126 static void loongson2_cpu_wait(void)
131 spin_lock_irqsave(&loongson2_wait_lock
, flags
);
132 cpu_freq
= readl(LOONGSON_CHIPCFG
);
133 /* Put CPU into wait mode */
134 writel(readl(LOONGSON_CHIPCFG
) & ~0x7, LOONGSON_CHIPCFG
);
135 /* Restore CPU state */
136 writel(cpu_freq
, LOONGSON_CHIPCFG
);
137 spin_unlock_irqrestore(&loongson2_wait_lock
, flags
);
141 static int __init
cpufreq_init(void)
145 /* Register platform stuff */
146 ret
= platform_driver_register(&platform_driver
);
150 pr_info("Loongson-2F CPU frequency driver\n");
152 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block
,
153 CPUFREQ_TRANSITION_NOTIFIER
);
155 ret
= cpufreq_register_driver(&loongson2_cpufreq_driver
);
157 if (!ret
&& !nowait
) {
158 saved_cpu_wait
= cpu_wait
;
159 cpu_wait
= loongson2_cpu_wait
;
165 static void __exit
cpufreq_exit(void)
167 if (!nowait
&& saved_cpu_wait
)
168 cpu_wait
= saved_cpu_wait
;
169 cpufreq_unregister_driver(&loongson2_cpufreq_driver
);
170 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block
,
171 CPUFREQ_TRANSITION_NOTIFIER
);
173 platform_driver_unregister(&platform_driver
);
176 module_init(cpufreq_init
);
177 module_exit(cpufreq_exit
);
179 module_param(nowait
, uint
, 0644);
180 MODULE_PARM_DESC(nowait
, "Disable Loongson-2F specific wait");
182 MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
183 MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
184 MODULE_LICENSE("GPL");