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. & Insititute 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
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>
20 #include <asm/clock.h>
23 #include <asm/mach-loongson/loongson.h>
27 static struct clk
*cpuclk
;
29 static void (*saved_cpu_wait
) (void);
31 static int loongson2_cpu_freq_notifier(struct notifier_block
*nb
,
32 unsigned long val
, void *data
);
34 static struct notifier_block loongson2_cpufreq_notifier_block
= {
35 .notifier_call
= loongson2_cpu_freq_notifier
38 static int loongson2_cpu_freq_notifier(struct notifier_block
*nb
,
39 unsigned long val
, void *data
)
41 if (val
== CPUFREQ_POSTCHANGE
)
42 current_cpu_data
.udelay_val
= loops_per_jiffy
;
47 static unsigned int loongson2_cpufreq_get(unsigned int cpu
)
49 return clk_get_rate(cpuclk
);
53 * Here we notify other drivers of the proposed change and the final change.
55 static int loongson2_cpufreq_target(struct cpufreq_policy
*policy
,
56 unsigned int target_freq
,
57 unsigned int relation
)
59 unsigned int cpu
= policy
->cpu
;
60 unsigned int newstate
= 0;
61 cpumask_t cpus_allowed
;
62 struct cpufreq_freqs freqs
;
65 cpus_allowed
= current
->cpus_allowed
;
66 set_cpus_allowed_ptr(current
, cpumask_of(cpu
));
68 if (cpufreq_frequency_table_target
69 (policy
, &loongson2_clockmod_table
[0], target_freq
, relation
,
74 ((cpu_clock_freq
/ 1000) *
75 loongson2_clockmod_table
[newstate
].driver_data
) / 8;
76 if (freq
< policy
->min
|| freq
> policy
->max
)
79 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq
* 1000);
81 freqs
.old
= loongson2_cpufreq_get(cpu
);
85 if (freqs
.new == freqs
.old
)
89 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
91 set_cpus_allowed_ptr(current
, &cpus_allowed
);
93 /* setting the cpu frequency */
94 clk_set_rate(cpuclk
, freq
);
97 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
99 pr_debug("cpufreq: set frequency %u kHz\n", freq
);
104 static int loongson2_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
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
);
116 rate
= cpu_clock_freq
/ 1000;
122 /* clock table init */
124 (loongson2_clockmod_table
[i
].frequency
!= CPUFREQ_TABLE_END
);
126 loongson2_clockmod_table
[i
].frequency
= (rate
* i
) / 8;
128 ret
= clk_set_rate(cpuclk
, rate
);
134 policy
->cur
= loongson2_cpufreq_get(policy
->cpu
);
136 cpufreq_frequency_table_get_attr(&loongson2_clockmod_table
[0],
139 return cpufreq_frequency_table_cpuinfo(policy
,
140 &loongson2_clockmod_table
[0]);
143 static int loongson2_cpufreq_verify(struct cpufreq_policy
*policy
)
145 return cpufreq_frequency_table_verify(policy
,
146 &loongson2_clockmod_table
[0]);
149 static int loongson2_cpufreq_exit(struct cpufreq_policy
*policy
)
155 static struct freq_attr
*loongson2_table_attr
[] = {
156 &cpufreq_freq_attr_scaling_available_freqs
,
160 static struct cpufreq_driver loongson2_cpufreq_driver
= {
161 .owner
= THIS_MODULE
,
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
,
171 static struct platform_device_id platform_device_ids
[] = {
173 .name
= "loongson2_cpufreq",
178 MODULE_DEVICE_TABLE(platform
, platform_device_ids
);
180 static struct platform_driver platform_driver
= {
182 .name
= "loongson2_cpufreq",
183 .owner
= THIS_MODULE
,
185 .id_table
= platform_device_ids
,
189 * This is the simple version of Loongson-2 wait, Maybe we need do this in
190 * interrupt disabled context.
193 static DEFINE_SPINLOCK(loongson2_wait_lock
);
195 static void loongson2_cpu_wait(void)
200 spin_lock_irqsave(&loongson2_wait_lock
, flags
);
201 cpu_freq
= LOONGSON_CHIPCFG0
;
202 LOONGSON_CHIPCFG0
&= ~0x7; /* Put CPU into wait mode */
203 LOONGSON_CHIPCFG0
= cpu_freq
; /* Restore CPU state */
204 spin_unlock_irqrestore(&loongson2_wait_lock
, flags
);
208 static int __init
cpufreq_init(void)
212 /* Register platform stuff */
213 ret
= platform_driver_register(&platform_driver
);
217 pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
219 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block
,
220 CPUFREQ_TRANSITION_NOTIFIER
);
222 ret
= cpufreq_register_driver(&loongson2_cpufreq_driver
);
224 if (!ret
&& !nowait
) {
225 saved_cpu_wait
= cpu_wait
;
226 cpu_wait
= loongson2_cpu_wait
;
232 static void __exit
cpufreq_exit(void)
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
);
240 platform_driver_unregister(&platform_driver
);
243 module_init(cpufreq_init
);
244 module_exit(cpufreq_exit
);
246 module_param(nowait
, uint
, 0644);
247 MODULE_PARM_DESC(nowait
, "Disable Loongson-2F specific wait");
249 MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
250 MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
251 MODULE_LICENSE("GPL");