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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Dave Jones32ee8c32006-02-28 00:43:23 -05002 * elanfreq: cpufreq driver for the AMD ELAN family
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * (c) Copyright 2002 Robert Schwebel <r.schwebel@pengutronix.de>
5 *
Dave Jones32ee8c32006-02-28 00:43:23 -05006 * Parts of this code are (c) Sven Geggus <sven@geggus.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
Dave Jones32ee8c32006-02-28 00:43:23 -05008 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 *
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
Dave Jones32ee8c32006-02-28 00:43:23 -050013 * 2 of the License, or (at your option) any later version.
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 *
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/delay.h>
24#include <linux/cpufreq.h>
25
Andi Kleenfa8031a2012-01-26 00:09:12 +010026#include <asm/cpu_device_id.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <asm/msr.h>
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +020028#include <linux/timex.h>
29#include <linux/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Dave Jones32ee8c32006-02-28 00:43:23 -050031#define REG_CSCIR 0x22 /* Chip Setup and Control Index Register */
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#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/*
Dave Jones32ee8c32006-02-28 00:43:23 -050044 * It is important that the frequencies
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 * are listed in ascending order here!
46 */
Dave Jones460f5ef2008-07-30 13:01:42 -040047static struct s_elan_multiplier elan_multiplier[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 {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[] = {
Viresh Kumar7f4b0462014-03-28 19:11:47 +053059 {0, 0, 1000},
60 {0, 1, 2000},
61 {0, 2, 4000},
62 {0, 3, 8000},
63 {0, 4, 16000},
64 {0, 5, 33000},
65 {0, 6, 66000},
66 {0, 7, 99000},
67 {0, 0, CPUFREQ_TABLE_END},
Linus Torvalds1da177e2005-04-16 15:20:36 -070068};
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
Dave Jones32ee8c32006-02-28 00:43:23 -050075 * at the moment. Frequencies from 1 to 33 MHz are generated
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 * the normal way, 66 and 99 MHz are called "Hyperspeed Mode"
Dave Jones32ee8c32006-02-28 00:43:23 -050077 * and have the rest of the chip running with 33 MHz.
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 */
79
80static unsigned int elanfreq_get_cpu_frequency(unsigned int cpu)
81{
Dave Jones32ee8c32006-02-28 00:43:23 -050082 u8 clockspeed_reg; /* Clock Speed Register */
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 local_irq_disable();
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +020085 outb_p(0x80, REG_CSCIR);
Dave Jones32ee8c32006-02-28 00:43:23 -050086 clockspeed_reg = inb_p(REG_CSCDR);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 local_irq_enable();
88
Dave Jones32ee8c32006-02-28 00:43:23 -050089 if ((clockspeed_reg & 0xE0) == 0xE0)
90 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Dave Jones32ee8c32006-02-28 00:43:23 -050092 /* Are we in CPU clock multiplied mode (66/99 MHz)? */
93 if ((clockspeed_reg & 0xE0) == 0xC0) {
94 if ((clockspeed_reg & 0x01) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 return 66000;
Dave Jones32ee8c32006-02-28 00:43:23 -050096 else
97 return 99000;
98 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 /* 33 MHz is not 32 MHz... */
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200101 if ((clockspeed_reg & 0xE0) == 0xA0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 return 33000;
103
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200104 return (1<<((clockspeed_reg & 0xE0) >> 5)) * 1000;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
106
107
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530108static int elanfreq_target(struct cpufreq_policy *policy,
109 unsigned int state)
Dave Jones32ee8c32006-02-28 00:43:23 -0500110{
Dave Jones32ee8c32006-02-28 00:43:23 -0500111 /*
112 * Access to the Elan's internal registers is indexed via
113 * 0x22: Chip Setup & Control Register Index Register (CSCI)
114 * 0x23: Chip Setup & Control Register Data Register (CSCD)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 *
116 */
117
Dave Jones32ee8c32006-02-28 00:43:23 -0500118 /*
119 * 0x40 is the Power Management Unit's Force Mode Register.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 * Bit 6 enables Hyperspeed Mode (66/100 MHz core frequency)
121 */
122
123 local_irq_disable();
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200124 outb_p(0x40, REG_CSCIR); /* Disable hyperspeed mode */
125 outb_p(0x00, REG_CSCDR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 local_irq_enable(); /* wait till internal pipelines and */
127 udelay(1000); /* buffers have cleaned up */
128
129 local_irq_disable();
130
131 /* now, set the CPU clock speed register (0x80) */
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200132 outb_p(0x80, REG_CSCIR);
133 outb_p(elan_multiplier[state].val80h, REG_CSCDR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
135 /* now, the hyperspeed bit in PMU Force Mode Register (0x40) */
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200136 outb_p(0x40, REG_CSCIR);
137 outb_p(elan_multiplier[state].val40h, REG_CSCDR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 udelay(10000);
139 local_irq_enable();
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 return 0;
142}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143/*
144 * Module init and exit code
145 */
146
147static int elanfreq_cpu_init(struct cpufreq_policy *policy)
148{
Mike Travis92cb7612007-10-19 20:35:04 +0200149 struct cpuinfo_x86 *c = &cpu_data(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 unsigned int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152 /* capability check */
153 if ((c->x86_vendor != X86_VENDOR_AMD) ||
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200154 (c->x86 != 4) || (c->x86_model != 10))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 return -ENODEV;
156
157 /* max freq */
158 if (!max_freq)
159 max_freq = elanfreq_get_cpu_frequency(0);
160
161 /* table init */
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200162 for (i = 0; (elanfreq_table[i].frequency != CPUFREQ_TABLE_END); i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 if (elanfreq_table[i].frequency > max_freq)
164 elanfreq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
165 }
166
167 /* cpuinfo and default policy values */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
Viresh Kumar55bb85b2013-09-16 18:56:15 +0530170 return cpufreq_table_validate_and_show(policy, elanfreq_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171}
172
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174#ifndef MODULE
175/**
176 * elanfreq_setup - elanfreq command line parameter parsing
177 *
178 * elanfreq command line parameter. Use:
179 * elanfreq=66000
180 * to set the maximum CPU frequency to 66 MHz. Note that in
181 * case you do not give this boot parameter, the maximum
182 * frequency will fall back to _current_ CPU frequency which
183 * might be lower. If you build this as a module, use the
184 * max_freq module parameter instead.
185 */
186static int __init elanfreq_setup(char *str)
187{
188 max_freq = simple_strtoul(str, &str, 0);
189 printk(KERN_WARNING "You're using the deprecated elanfreq command line option. Use elanfreq.max_freq instead, please!\n");
190 return 1;
191}
192__setup("elanfreq=", elanfreq_setup);
193#endif
194
195
Linus Torvalds221dee22007-02-26 14:55:48 -0800196static struct cpufreq_driver elanfreq_driver = {
Dave Jones32ee8c32006-02-28 00:43:23 -0500197 .get = elanfreq_get_cpu_frequency,
Viresh Kumar06494eb2013-10-03 20:28:05 +0530198 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530199 .target_index = elanfreq_target,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 .init = elanfreq_cpu_init,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 .name = "elanfreq",
Viresh Kumar06494eb2013-10-03 20:28:05 +0530202 .attr = cpufreq_generic_attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203};
204
Andi Kleenfa8031a2012-01-26 00:09:12 +0100205static const struct x86_cpu_id elan_id[] = {
206 { X86_VENDOR_AMD, 4, 10, },
207 {}
208};
209MODULE_DEVICE_TABLE(x86cpu, elan_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
Dave Jones32ee8c32006-02-28 00:43:23 -0500211static int __init elanfreq_init(void)
212{
Andi Kleenfa8031a2012-01-26 00:09:12 +0100213 if (!x86_match_cpu(elan_id))
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200214 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 return cpufreq_register_driver(&elanfreq_driver);
216}
217
218
Dave Jones32ee8c32006-02-28 00:43:23 -0500219static void __exit elanfreq_exit(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
221 cpufreq_unregister_driver(&elanfreq_driver);
222}
223
224
Paolo Ciarrocchi18c6faa2008-07-28 13:00:49 +0200225module_param(max_freq, int, 0444);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227MODULE_LICENSE("GPL");
Dave Jones04cd1a92009-01-17 22:50:33 -0500228MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, "
229 "Sven Geggus <sven@geggus.net>");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
231
232module_init(elanfreq_init);
233module_exit(elanfreq_exit);