2 * clock scaling for the UniCore-II
4 * Code specific to PKUnity SoC and UniCore ISA
6 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
7 * Copyright (C) 2001-2010 Guan Xuetao
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/kernel.h>
15 #include <linux/types.h>
16 #include <linux/init.h>
17 #include <linux/clk.h>
18 #include <linux/cpufreq.h>
20 #include <mach/hardware.h>
22 static struct cpufreq_driver ucv2_driver
;
24 /* make sure that only the "userspace" governor is run
25 * -- anything else wouldn't make sense on this platform, anyway.
27 static int ucv2_verify_speed(struct cpufreq_policy
*policy
)
32 cpufreq_verify_within_cpu_limits(policy
);
36 static unsigned int ucv2_getspeed(unsigned int cpu
)
38 struct clk
*mclk
= clk_get(NULL
, "MAIN_CLK");
42 return clk_get_rate(mclk
)/1000;
45 static int ucv2_target(struct cpufreq_policy
*policy
,
46 unsigned int target_freq
,
47 unsigned int relation
)
49 unsigned int cur
= ucv2_getspeed(0);
50 struct cpufreq_freqs freqs
;
51 struct clk
*mclk
= clk_get(NULL
, "MAIN_CLK");
53 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
55 if (!clk_set_rate(mclk
, target_freq
* 1000)) {
57 freqs
.new = target_freq
;
60 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
65 static int __init
ucv2_cpu_init(struct cpufreq_policy
*policy
)
69 policy
->min
= policy
->cpuinfo
.min_freq
= 250000;
70 policy
->max
= policy
->cpuinfo
.max_freq
= 1000000;
71 policy
->cpuinfo
.transition_latency
= CPUFREQ_ETERNAL
;
75 static struct cpufreq_driver ucv2_driver
= {
76 .flags
= CPUFREQ_STICKY
,
77 .verify
= ucv2_verify_speed
,
78 .target
= ucv2_target
,
80 .init
= ucv2_cpu_init
,
84 static int __init
ucv2_cpufreq_init(void)
86 return cpufreq_register_driver(&ucv2_driver
);
89 arch_initcall(ucv2_cpufreq_init
);