aboutsummaryrefslogtreecommitdiffstats
path: root/arch/blackfin/mach-bf548/cpu.c
blob: 4298a3ccfbfc5de35523b1de69d8152f733d0ca7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
 * File:         arch/blackfin/mach-bf548/cpu.c
 * Based on:
 * Author:
 *
 * Created:
 * Description:  clock scaling for the bf54x
 *
 * Modified:
 *               Copyright 2004-2007 Analog Devices Inc.
 *
 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <asm/dpmc.h>
#include <linux/fs.h>
#include <asm/bfin-global.h>

/* CONFIG_CLKIN_HZ=25000000 */
#define VCO5 (CONFIG_CLKIN_HZ*45)
#define VCO4 (CONFIG_CLKIN_HZ*36)
#define VCO3 (CONFIG_CLKIN_HZ*27)
#define VCO2 (CONFIG_CLKIN_HZ*18)
#define VCO1 (CONFIG_CLKIN_HZ*9)
#define VCO(x) VCO##x

#define MFREQ(x) {VCO(x),VCO(x)/4},{VCO(x),VCO(x)/2},{VCO(x),VCO(x)}
/* frequency */
static struct cpufreq_frequency_table bf548_freq_table[] = {
	MFREQ(1),
	MFREQ(3),
	{VCO4, VCO4 / 2}, {VCO4, VCO4},
	MFREQ(5),
	{0, CPUFREQ_TABLE_END},
};

/*
 * dpmc_fops->ioctl()
 * static int dpmc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 */
static int bf548_getfreq(unsigned int cpu)
{
	unsigned long cclk_mhz;

	/* The driver only support single cpu */
	if (cpu == 0)
		dpmc_fops.ioctl(NULL, NULL, IOCTL_GET_CORECLOCK, &cclk_mhz);
	else
		cclk_mhz = -1;

	return cclk_mhz;
}

static int bf548_target(struct cpufreq_policy *policy,
			    unsigned int target_freq, unsigned int relation)
{
	unsigned long cclk_mhz;
	unsigned long vco_mhz;
	unsigned long flags;
	unsigned int index;
	struct cpufreq_freqs freqs;

	if (cpufreq_frequency_table_target(policy, bf548_freq_table, target_freq, relation, &index))
		return -EINVAL;

	cclk_mhz = bf548_freq_table[index].frequency;
	vco_mhz = bf548_freq_table[index].index;

	dpmc_fops.ioctl(NULL, NULL, IOCTL_CHANGE_FREQUENCY, &vco_mhz);
	freqs.old = bf548_getfreq(0);
	freqs.new = cclk_mhz;
	freqs.cpu = 0;

	pr_debug("cclk begin change to cclk %d,vco=%d,index=%d,target=%d,oldfreq=%d\n",
	         cclk_mhz, vco_mhz, index, target_freq, freqs.old);

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	local_irq_save(flags);
	dpmc_fops.ioctl(NULL, NULL, IOCTL_SET_CCLK, &cclk_mhz);
	local_irq_restore(flags);
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	vco_mhz = get_vco();
	cclk_mhz = get_cclk();
	return 0;
}

/* make sure that only the "userspace" governor is run -- anything else wouldn't make sense on
 * this platform, anyway.
 */
static int bf548_verify_speed(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, &bf548_freq_table);
}

static int __init __bf548_cpu_init(struct cpufreq_policy *policy)
{
	if (policy->cpu != 0)
		return -EINVAL;

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	/*Now ,only support one cpu */
	policy->cur = bf548_getfreq(0);
	cpufreq_frequency_table_get_attr(bf548_freq_table, policy->cpu);
	return cpufreq_frequency_table_cpuinfo(policy, bf548_freq_table);
}

static struct freq_attr *bf548_freq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver bf548_driver = {
	.verify = bf548_verify_speed,
	.target = bf548_target,
	.get = bf548_getfreq,
	.init = __bf548_cpu_init,
	.name = "bf548",
	.owner = THIS_MODULE,
	.attr = bf548_freq_attr,
};

static int __init bf548_cpu_init(void)
{
	return cpufreq_register_driver(&bf548_driver);
}

static void __exit bf548_cpu_exit(void)
{
	cpufreq_unregister_driver(&bf548_driver);
}

MODULE_AUTHOR("Mickael Kang");
MODULE_DESCRIPTION("cpufreq driver for BF548 CPU");
MODULE_LICENSE("GPL");

module_init(bf548_cpu_init);
module_exit(bf548_cpu_exit);