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
|
/*
* sc520_freq.c: cpufreq driver for the AMD Elan sc520
*
* Copyright (C) 2005 Sean Young <sean@mess.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.
*
* Based on elanfreq.c
*
* 2005-03-30: - initial revision
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/cpufreq.h>
#include <linux/timex.h>
#include <linux/io.h>
#include <asm/cpu_device_id.h>
#include <asm/msr.h>
#define MMCR_BASE 0xfffef000 /* The default base address */
#define OFFS_CPUCTL 0x2 /* CPU Control Register */
static __u8 __iomem *cpuctl;
#define PFX "sc520_freq: "
static struct cpufreq_frequency_table sc520_freq_table[] = {
{0, 0x01, 100000},
{0, 0x02, 133000},
{0, 0, CPUFREQ_TABLE_END},
};
static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)
{
u8 clockspeed_reg = *cpuctl;
switch (clockspeed_reg & 0x03) {
default:
pr_err(PFX "error: cpuctl register has unexpected value %02x\n",
clockspeed_reg);
case 0x01:
return 100000;
case 0x02:
return 133000;
}
}
static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state)
{
u8 clockspeed_reg;
local_irq_disable();
clockspeed_reg = *cpuctl & ~0x03;
*cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data;
local_irq_enable();
return 0;
}
/*
* Module init and exit code
*/
static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
{
struct cpuinfo_x86 *c = &cpu_data(0);
/* capability check */
if (c->x86_vendor != X86_VENDOR_AMD ||
c->x86 != 4 || c->x86_model != 9)
return -ENODEV;
/* cpuinfo and default policy values */
policy->cpuinfo.transition_latency = 1000000; /* 1ms */
return cpufreq_table_validate_and_show(policy, sc520_freq_table);
}
static struct cpufreq_driver sc520_freq_driver = {
.get = sc520_freq_get_cpu_frequency,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = sc520_freq_target,
.init = sc520_freq_cpu_init,
.name = "sc520_freq",
.attr = cpufreq_generic_attr,
};
static const struct x86_cpu_id sc520_ids[] = {
{ X86_VENDOR_AMD, 4, 9 },
{}
};
MODULE_DEVICE_TABLE(x86cpu, sc520_ids);
static int __init sc520_freq_init(void)
{
int err;
if (!x86_match_cpu(sc520_ids))
return -ENODEV;
cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
if (!cpuctl) {
pr_err("sc520_freq: error: failed to remap memory\n");
return -ENOMEM;
}
err = cpufreq_register_driver(&sc520_freq_driver);
if (err)
iounmap(cpuctl);
return err;
}
static void __exit sc520_freq_exit(void)
{
cpufreq_unregister_driver(&sc520_freq_driver);
iounmap(cpuctl);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sean Young <sean@mess.org>");
MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU");
module_init(sc520_freq_init);
module_exit(sc520_freq_exit);
|
