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  • only in /netgear-WNDR4500-V1.0.1.40_1.0.68/src/linux/linux-2.6/arch/i386/kernel/cpu/cpufreq/
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)
90		return 0;
91
92	/* Are we in CPU clock multiplied mode (66/99 MHz)? */
93	if ((clockspeed_reg & 0xE0) == 0xC0) {
94		if ((clockspeed_reg & 0x01) == 0)
95			return 66000;
96		else
97			return 99000;
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",
131			elan_multiplier[state].clock);
132
133
134	/*
135	 * Access to the Elan's internal registers is indexed via
136	 * 0x22: Chip Setup & Control Register Index Register (CSCI)
137	 * 0x23: Chip Setup & Control Register Data  Register (CSCD)
138	 *
139	 */
140
141	/*
142	 * 0x40 is the Power Management Unit's Force Mode Register.
143	 * Bit 6 enables Hyperspeed Mode (66/100 MHz core frequency)
144	 */
145
146	local_irq_disable();
147	outb_p(0x40,REG_CSCIR);		/* Disable hyperspeed mode */
148	outb_p(0x00,REG_CSCDR);
149	local_irq_enable();		/* wait till internal pipelines and */
150	udelay(1000);			/* buffers have cleaned up          */
151
152	local_irq_disable();
153
154	/* now, set the CPU clock speed register (0x80) */
155	outb_p(0x80,REG_CSCIR);
156	outb_p(elan_multiplier[state].val80h,REG_CSCDR);
157
158	/* now, the hyperspeed bit in PMU Force Mode Register (0x40) */
159	outb_p(0x40,REG_CSCIR);
160	outb_p(elan_multiplier[state].val40h,REG_CSCDR);
161	udelay(10000);
162	local_irq_enable();
163
164	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
165};
166
167
168/**
169 *	elanfreq_validatespeed: test if frequency range is valid
170 *	@policy: the policy to validate
171 *
172 *	This function checks if a given frequency range in kHz is valid
173 *	for the hardware supported by the driver.
174 */
175
176static int elanfreq_verify (struct cpufreq_policy *policy)
177{
178	return cpufreq_frequency_table_verify(policy, &elanfreq_table[0]);
179}
180
181static int elanfreq_target (struct cpufreq_policy *policy,
182			    unsigned int target_freq,
183			    unsigned int relation)
184{
185	unsigned int newstate = 0;
186
187	if (cpufreq_frequency_table_target(policy, &elanfreq_table[0], target_freq, relation, &newstate))
188		return -EINVAL;
189
190	elanfreq_set_cpu_state(newstate);
191
192	return 0;
193}
194
195
196/*
197 *	Module init and exit code
198 */
199
200static int elanfreq_cpu_init(struct cpufreq_policy *policy)
201{
202	struct cpuinfo_x86 *c = cpu_data;
203	unsigned int i;
204	int result;
205
206	/* capability check */
207	if ((c->x86_vendor != X86_VENDOR_AMD) ||
208	    (c->x86 != 4) || (c->x86_model!=10))
209		return -ENODEV;
210
211	/* max freq */
212	if (!max_freq)
213		max_freq = elanfreq_get_cpu_frequency(0);
214
215	/* table init */
216	for (i=0; (elanfreq_table[i].frequency != CPUFREQ_TABLE_END); i++) {
217		if (elanfreq_table[i].frequency > max_freq)
218			elanfreq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
219	}
220
221	/* cpuinfo and default policy values */
222	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
223	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
224	policy->cur = elanfreq_get_cpu_frequency(0);
225
226	result = cpufreq_frequency_table_cpuinfo(policy, elanfreq_table);
227	if (result)
228		return (result);
229
230	cpufreq_frequency_table_get_attr(elanfreq_table, policy->cpu);
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		printk(KERN_INFO "elanfreq: error: no Elan processor found!\n");
290                return -ENODEV;
291	}
292	return cpufreq_register_driver(&elanfreq_driver);
293}
294
295
296static void __exit elanfreq_exit(void)
297{
298	cpufreq_unregister_driver(&elanfreq_driver);
299}
300
301
302module_param (max_freq, int, 0444);
303
304MODULE_LICENSE("GPL");
305MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, Sven Geggus <sven@geggus.net>");
306MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
307
308module_init(elanfreq_init);
309module_exit(elanfreq_exit);
310