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19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/init.h>
24
25#include <linux/delay.h>
26#include <linux/cpufreq.h>
27
28#include <asm/cpu_device_id.h>
29#include <asm/msr.h>
30#include <linux/timex.h>
31#include <linux/io.h>
32
33#define REG_CSCIR 0x22
34#define REG_CSCDR 0x23
35
36
37static int max_freq;
38
39struct s_elan_multiplier {
40 int clock;
41 int val40h;
42 int val80h;
43};
44
45
46
47
48
49static struct s_elan_multiplier elan_multiplier[] = {
50 {1000, 0x02, 0x18},
51 {2000, 0x02, 0x10},
52 {4000, 0x02, 0x08},
53 {8000, 0x00, 0x00},
54 {16000, 0x00, 0x02},
55 {33000, 0x00, 0x04},
56 {66000, 0x01, 0x04},
57 {99000, 0x01, 0x05}
58};
59
60static struct cpufreq_frequency_table elanfreq_table[] = {
61 {0, 0, 1000},
62 {0, 1, 2000},
63 {0, 2, 4000},
64 {0, 3, 8000},
65 {0, 4, 16000},
66 {0, 5, 33000},
67 {0, 6, 66000},
68 {0, 7, 99000},
69 {0, 0, CPUFREQ_TABLE_END},
70};
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81
82static unsigned int elanfreq_get_cpu_frequency(unsigned int cpu)
83{
84 u8 clockspeed_reg;
85
86 local_irq_disable();
87 outb_p(0x80, REG_CSCIR);
88 clockspeed_reg = inb_p(REG_CSCDR);
89 local_irq_enable();
90
91 if ((clockspeed_reg & 0xE0) == 0xE0)
92 return 0;
93
94
95 if ((clockspeed_reg & 0xE0) == 0xC0) {
96 if ((clockspeed_reg & 0x01) == 0)
97 return 66000;
98 else
99 return 99000;
100 }
101
102
103 if ((clockspeed_reg & 0xE0) == 0xA0)
104 return 33000;
105
106 return (1<<((clockspeed_reg & 0xE0) >> 5)) * 1000;
107}
108
109
110static int elanfreq_target(struct cpufreq_policy *policy,
111 unsigned int state)
112{
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124
125 local_irq_disable();
126 outb_p(0x40, REG_CSCIR);
127 outb_p(0x00, REG_CSCDR);
128 local_irq_enable();
129 udelay(1000);
130
131 local_irq_disable();
132
133
134 outb_p(0x80, REG_CSCIR);
135 outb_p(elan_multiplier[state].val80h, REG_CSCDR);
136
137
138 outb_p(0x40, REG_CSCIR);
139 outb_p(elan_multiplier[state].val40h, REG_CSCDR);
140 udelay(10000);
141 local_irq_enable();
142
143 return 0;
144}
145
146
147
148
149static int elanfreq_cpu_init(struct cpufreq_policy *policy)
150{
151 struct cpuinfo_x86 *c = &cpu_data(0);
152 struct cpufreq_frequency_table *pos;
153
154
155 if ((c->x86_vendor != X86_VENDOR_AMD) ||
156 (c->x86 != 4) || (c->x86_model != 10))
157 return -ENODEV;
158
159
160 if (!max_freq)
161 max_freq = elanfreq_get_cpu_frequency(0);
162
163
164 cpufreq_for_each_entry(pos, elanfreq_table)
165 if (pos->frequency > max_freq)
166 pos->frequency = CPUFREQ_ENTRY_INVALID;
167
168 policy->freq_table = elanfreq_table;
169 return 0;
170}
171
172
173#ifndef MODULE
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184
185static int __init elanfreq_setup(char *str)
186{
187 max_freq = simple_strtoul(str, &str, 0);
188 pr_warn("You're using the deprecated elanfreq command line option. Use elanfreq.max_freq instead, please!\n");
189 return 1;
190}
191__setup("elanfreq=", elanfreq_setup);
192#endif
193
194
195static struct cpufreq_driver elanfreq_driver = {
196 .get = elanfreq_get_cpu_frequency,
197 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
198 .verify = cpufreq_generic_frequency_table_verify,
199 .target_index = elanfreq_target,
200 .init = elanfreq_cpu_init,
201 .name = "elanfreq",
202 .attr = cpufreq_generic_attr,
203};
204
205static const struct x86_cpu_id elan_id[] = {
206 { X86_VENDOR_AMD, 4, 10, },
207 {}
208};
209MODULE_DEVICE_TABLE(x86cpu, elan_id);
210
211static int __init elanfreq_init(void)
212{
213 if (!x86_match_cpu(elan_id))
214 return -ENODEV;
215 return cpufreq_register_driver(&elanfreq_driver);
216}
217
218
219static void __exit elanfreq_exit(void)
220{
221 cpufreq_unregister_driver(&elanfreq_driver);
222}
223
224
225module_param(max_freq, int, 0444);
226
227MODULE_LICENSE("GPL");
228MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, "
229 "Sven Geggus <sven@geggus.net>");
230MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
231
232module_init(elanfreq_init);
233module_exit(elanfreq_exit);
234