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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/cpu/cpufreq/elanfreq.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/elanfreq.c')
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1 files changed, 312 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/elanfreq.c b/arch/i386/kernel/cpu/cpufreq/elanfreq.c
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index 000000000000..3f7caa4ae6d6
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1/*
2 * elanfreq: cpufreq driver for the AMD ELAN family
3 *
4 * (c) Copyright 2002 Robert Schwebel <r.schwebel@pengutronix.de>
5 *
6 * Parts of this code are (c) Sven Geggus <sven@geggus.net>
7 *
8 * All Rights Reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * 2002-02-13: - initial revision for 2.4.18-pre9 by Robert Schwebel
16 *
17 */
18
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/init.h>
22
23#include <linux/slab.h>
24#include <linux/delay.h>
25#include <linux/cpufreq.h>
26
27#include <asm/msr.h>
28#include <asm/timex.h>
29#include <asm/io.h>
30
31#define REG_CSCIR 0x22 /* Chip Setup and Control Index Register */
32#define REG_CSCDR 0x23 /* Chip Setup and Control Data Register */
33
34/* Module parameter */
35static int max_freq;
36
37struct s_elan_multiplier {
38 int clock; /* frequency in kHz */
39 int val40h; /* PMU Force Mode register */
40 int val80h; /* CPU Clock Speed Register */
41};
42
43/*
44 * It is important that the frequencies
45 * are listed in ascending order here!
46 */
47struct s_elan_multiplier elan_multiplier[] = {
48 {1000, 0x02, 0x18},
49 {2000, 0x02, 0x10},
50 {4000, 0x02, 0x08},
51 {8000, 0x00, 0x00},
52 {16000, 0x00, 0x02},
53 {33000, 0x00, 0x04},
54 {66000, 0x01, 0x04},
55 {99000, 0x01, 0x05}
56};
57
58static struct cpufreq_frequency_table elanfreq_table[] = {
59 {0, 1000},
60 {1, 2000},
61 {2, 4000},
62 {3, 8000},
63 {4, 16000},
64 {5, 33000},
65 {6, 66000},
66 {7, 99000},
67 {0, CPUFREQ_TABLE_END},
68};
69
70
71/**
72 * elanfreq_get_cpu_frequency: determine current cpu speed
73 *
74 * Finds out at which frequency the CPU of the Elan SOC runs
75 * at the moment. Frequencies from 1 to 33 MHz are generated
76 * the normal way, 66 and 99 MHz are called "Hyperspeed Mode"
77 * and have the rest of the chip running with 33 MHz.
78 */
79
80static unsigned int elanfreq_get_cpu_frequency(unsigned int cpu)
81{
82 u8 clockspeed_reg; /* Clock Speed Register */
83
84 local_irq_disable();
85 outb_p(0x80,REG_CSCIR);
86 clockspeed_reg = inb_p(REG_CSCDR);
87 local_irq_enable();
88
89 if ((clockspeed_reg & 0xE0) == 0xE0) { return 0; }
90
91 /* Are we in CPU clock multiplied mode (66/99 MHz)? */
92 if ((clockspeed_reg & 0xE0) == 0xC0) {
93 if ((clockspeed_reg & 0x01) == 0) {
94 return 66000;
95 } else {
96 return 99000;
97 }
98 }
99
100 /* 33 MHz is not 32 MHz... */
101 if ((clockspeed_reg & 0xE0)==0xA0)
102 return 33000;
103
104 return ((1<<((clockspeed_reg & 0xE0) >> 5)) * 1000);
105}
106
107
108/**
109 * elanfreq_set_cpu_frequency: Change the CPU core frequency
110 * @cpu: cpu number
111 * @freq: frequency in kHz
112 *
113 * This function takes a frequency value and changes the CPU frequency
114 * according to this. Note that the frequency has to be checked by
115 * elanfreq_validatespeed() for correctness!
116 *
117 * There is no return value.
118 */
119
120static void elanfreq_set_cpu_state (unsigned int state) {
121
122 struct cpufreq_freqs freqs;
123
124 freqs.old = elanfreq_get_cpu_frequency(0);
125 freqs.new = elan_multiplier[state].clock;
126 freqs.cpu = 0; /* elanfreq.c is UP only driver */
127
128 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
129
130 printk(KERN_INFO "elanfreq: attempting to set frequency to %i kHz\n",elan_multiplier[state].clock);
131
132
133 /*
134 * Access to the Elan's internal registers is indexed via
135 * 0x22: Chip Setup & Control Register Index Register (CSCI)
136 * 0x23: Chip Setup & Control Register Data Register (CSCD)
137 *
138 */
139
140 /*
141 * 0x40 is the Power Management Unit's Force Mode Register.
142 * Bit 6 enables Hyperspeed Mode (66/100 MHz core frequency)
143 */
144
145 local_irq_disable();
146 outb_p(0x40,REG_CSCIR); /* Disable hyperspeed mode */
147 outb_p(0x00,REG_CSCDR);
148 local_irq_enable(); /* wait till internal pipelines and */
149 udelay(1000); /* buffers have cleaned up */
150
151 local_irq_disable();
152
153 /* now, set the CPU clock speed register (0x80) */
154 outb_p(0x80,REG_CSCIR);
155 outb_p(elan_multiplier[state].val80h,REG_CSCDR);
156
157 /* now, the hyperspeed bit in PMU Force Mode Register (0x40) */
158 outb_p(0x40,REG_CSCIR);
159 outb_p(elan_multiplier[state].val40h,REG_CSCDR);
160 udelay(10000);
161 local_irq_enable();
162
163 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
164};
165
166
167/**
168 * elanfreq_validatespeed: test if frequency range is valid
169 * @policy: the policy to validate
170 *
171 * This function checks if a given frequency range in kHz is valid
172 * for the hardware supported by the driver.
173 */
174
175static int elanfreq_verify (struct cpufreq_policy *policy)
176{
177 return cpufreq_frequency_table_verify(policy, &elanfreq_table[0]);
178}
179
180static int elanfreq_target (struct cpufreq_policy *policy,
181 unsigned int target_freq,
182 unsigned int relation)
183{
184 unsigned int newstate = 0;
185
186 if (cpufreq_frequency_table_target(policy, &elanfreq_table[0], target_freq, relation, &newstate))
187 return -EINVAL;
188
189 elanfreq_set_cpu_state(newstate);
190
191 return 0;
192}
193
194
195/*
196 * Module init and exit code
197 */
198
199static int elanfreq_cpu_init(struct cpufreq_policy *policy)
200{
201 struct cpuinfo_x86 *c = cpu_data;
202 unsigned int i;
203 int result;
204
205 /* capability check */
206 if ((c->x86_vendor != X86_VENDOR_AMD) ||
207 (c->x86 != 4) || (c->x86_model!=10))
208 return -ENODEV;
209
210 /* max freq */
211 if (!max_freq)
212 max_freq = elanfreq_get_cpu_frequency(0);
213
214 /* table init */
215 for (i=0; (elanfreq_table[i].frequency != CPUFREQ_TABLE_END); i++) {
216 if (elanfreq_table[i].frequency > max_freq)
217 elanfreq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
218 }
219
220 /* cpuinfo and default policy values */
221 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
222 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
223 policy->cur = elanfreq_get_cpu_frequency(0);
224
225 result = cpufreq_frequency_table_cpuinfo(policy, elanfreq_table);
226 if (result)
227 return (result);
228
229 cpufreq_frequency_table_get_attr(elanfreq_table, policy->cpu);
230
231 return 0;
232}
233
234
235static int elanfreq_cpu_exit(struct cpufreq_policy *policy)
236{
237 cpufreq_frequency_table_put_attr(policy->cpu);
238 return 0;
239}
240
241
242#ifndef MODULE
243/**
244 * elanfreq_setup - elanfreq command line parameter parsing
245 *
246 * elanfreq command line parameter. Use:
247 * elanfreq=66000
248 * to set the maximum CPU frequency to 66 MHz. Note that in
249 * case you do not give this boot parameter, the maximum
250 * frequency will fall back to _current_ CPU frequency which
251 * might be lower. If you build this as a module, use the
252 * max_freq module parameter instead.
253 */
254static int __init elanfreq_setup(char *str)
255{
256 max_freq = simple_strtoul(str, &str, 0);
257 printk(KERN_WARNING "You're using the deprecated elanfreq command line option. Use elanfreq.max_freq instead, please!\n");
258 return 1;
259}
260__setup("elanfreq=", elanfreq_setup);
261#endif
262
263
264static struct freq_attr* elanfreq_attr[] = {
265 &cpufreq_freq_attr_scaling_available_freqs,
266 NULL,
267};
268
269
270static struct cpufreq_driver elanfreq_driver = {
271 .get = elanfreq_get_cpu_frequency,
272 .verify = elanfreq_verify,
273 .target = elanfreq_target,
274 .init = elanfreq_cpu_init,
275 .exit = elanfreq_cpu_exit,
276 .name = "elanfreq",
277 .owner = THIS_MODULE,
278 .attr = elanfreq_attr,
279};
280
281
282static int __init elanfreq_init(void)
283{
284 struct cpuinfo_x86 *c = cpu_data;
285
286 /* Test if we have the right hardware */
287 if ((c->x86_vendor != X86_VENDOR_AMD) ||
288 (c->x86 != 4) || (c->x86_model!=10))
289 {
290 printk(KERN_INFO "elanfreq: error: no Elan processor found!\n");
291 return -ENODEV;
292 }
293
294 return cpufreq_register_driver(&elanfreq_driver);
295}
296
297
298static void __exit elanfreq_exit(void)
299{
300 cpufreq_unregister_driver(&elanfreq_driver);
301}
302
303
304module_param (max_freq, int, 0444);
305
306MODULE_LICENSE("GPL");
307MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, Sven Geggus <sven@geggus.net>");
308MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
309
310module_init(elanfreq_init);
311module_exit(elanfreq_exit);
312