1/*
2 * clock scaling for the UniCore-II
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
7 *	Copyright (C) 2001-2010 Guan Xuetao
8 *
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.
12 */
13
14#include <linux/err.h>
15#include <linux/kernel.h>
16#include <linux/types.h>
17#include <linux/init.h>
18#include <linux/clk.h>
19#include <linux/cpufreq.h>
20
21#include <mach/hardware.h>
22
23static struct cpufreq_driver ucv2_driver;
24
25/* make sure that only the "userspace" governor is run
26 * -- anything else wouldn't make sense on this platform, anyway.
27 */
28static int ucv2_verify_speed(struct cpufreq_policy *policy)
29{
30	if (policy->cpu)
31		return -EINVAL;
32
33	cpufreq_verify_within_cpu_limits(policy);
34	return 0;
35}
36
37static int ucv2_target(struct cpufreq_policy *policy,
38			 unsigned int target_freq,
39			 unsigned int relation)
40{
41	struct cpufreq_freqs freqs;
42	int ret;
43
44	freqs.old = policy->cur;
45	freqs.new = target_freq;
46
47	cpufreq_freq_transition_begin(policy, &freqs);
48	ret = clk_set_rate(policy->clk, target_freq * 1000);
49	cpufreq_freq_transition_end(policy, &freqs, ret);
50
51	return ret;
52}
53
54static int __init ucv2_cpu_init(struct cpufreq_policy *policy)
55{
56	if (policy->cpu != 0)
57		return -EINVAL;
58
59	policy->min = policy->cpuinfo.min_freq = 250000;
60	policy->max = policy->cpuinfo.max_freq = 1000000;
61	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
62	policy->clk = clk_get(NULL, "MAIN_CLK");
63	return PTR_ERR_OR_ZERO(policy->clk);
64}
65
66static struct cpufreq_driver ucv2_driver = {
67	.flags		= CPUFREQ_STICKY,
68	.verify		= ucv2_verify_speed,
69	.target		= ucv2_target,
70	.get		= cpufreq_generic_get,
71	.init		= ucv2_cpu_init,
72	.name		= "UniCore-II",
73};
74
75static int __init ucv2_cpufreq_init(void)
76{
77	return cpufreq_register_driver(&ucv2_driver);
78}
79
80arch_initcall(ucv2_cpufreq_init);
81