aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/cpu/cpufreq/powernow-k6.c
blob: 222f8cfe3c578a106cfc1da38975fa5da1a047b9 (plain) (blame)
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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
/*
 *  This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
 *  (C) 2000-2003  Dave Jones, Arjan van de Ven, Janne Pänkälä, Dominik Brodowski.
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
 */

#include <linux/kernel.h>
#include <linux/module.h> 
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/ioport.h>
#include <linux/slab.h>

#include <asm/msr.h>
#include <asm/timex.h>
#include <asm/io.h>


#define POWERNOW_IOPORT 0xfff0         /* it doesn't matter where, as long
					  as it is unused */

static unsigned int                     busfreq;   /* FSB, in 10 kHz */
static unsigned int                     max_multiplier;


/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
static struct cpufreq_frequency_table clock_ratio[] = {
	{45,  /* 000 -> 4.5x */ 0},
	{50,  /* 001 -> 5.0x */ 0},
	{40,  /* 010 -> 4.0x */ 0},
	{55,  /* 011 -> 5.5x */ 0},
	{20,  /* 100 -> 2.0x */ 0},
	{30,  /* 101 -> 3.0x */ 0},
	{60,  /* 110 -> 6.0x */ 0},
	{35,  /* 111 -> 3.5x */ 0},
	{0, CPUFREQ_TABLE_END}
};


/**
 * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
 *
 *   Returns the current setting of the frequency multiplier. Core clock
 * speed is frequency of the Front-Side Bus multiplied with this value.
 */
static int powernow_k6_get_cpu_multiplier(void)
{
	u64             invalue = 0;
	u32             msrval;
	
	msrval = POWERNOW_IOPORT + 0x1;
	wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
	invalue=inl(POWERNOW_IOPORT + 0x8);
	msrval = POWERNOW_IOPORT + 0x0;
	wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */

	return clock_ratio[(invalue >> 5)&7].index;
}


/**
 * powernow_k6_set_state - set the PowerNow! multiplier
 * @best_i: clock_ratio[best_i] is the target multiplier
 *
 *   Tries to change the PowerNow! multiplier
 */
static void powernow_k6_set_state (unsigned int best_i)
{
	unsigned long           outvalue=0, invalue=0;
	unsigned long           msrval;
	struct cpufreq_freqs    freqs;

	if (clock_ratio[best_i].index > max_multiplier) {
		printk(KERN_ERR "cpufreq: invalid target frequency\n");
		return;
	}

	freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
	freqs.new = busfreq * clock_ratio[best_i].index;
	freqs.cpu = 0; /* powernow-k6.c is UP only driver */
	
	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	/* we now need to transform best_i to the BVC format, see AMD#23446 */

	outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);

	msrval = POWERNOW_IOPORT + 0x1;
	wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
	invalue=inl(POWERNOW_IOPORT + 0x8);
	invalue = invalue & 0xf;
	outvalue = outvalue | invalue;
	outl(outvalue ,(POWERNOW_IOPORT + 0x8));
	msrval = POWERNOW_IOPORT + 0x0;
	wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	return;
}


/**
 * powernow_k6_verify - verifies a new CPUfreq policy
 * @policy: new policy
 *
 * Policy must be within lowest and highest possible CPU Frequency,
 * and at least one possible state must be within min and max.
 */
static int powernow_k6_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
}


/**
 * powernow_k6_setpolicy - sets a new CPUFreq policy
 * @policy: new policy
 * @target_freq: the target frequency
 * @relation: how that frequency relates to achieved frequency (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 *
 * sets a new CPUFreq policy
 */
static int powernow_k6_target (struct cpufreq_policy *policy,
			       unsigned int target_freq,
			       unsigned int relation)
{
	unsigned int    newstate = 0;

	if (cpufreq_frequency_table_target(policy, &clock_ratio[0], target_freq, relation, &newstate))
		return -EINVAL;

	powernow_k6_set_state(newstate);

	return 0;
}


static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
{
	unsigned int i;
	int result;

	if (policy->cpu != 0)
		return -ENODEV;

	/* get frequencies */
	max_multiplier = powernow_k6_get_cpu_multiplier();
	busfreq = cpu_khz / max_multiplier;

	/* table init */
 	for (i=0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
		if (clock_ratio[i].index > max_multiplier)
			clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
		else
			clock_ratio[i].frequency = busfreq * clock_ratio[i].index;
	}

	/* cpuinfo and default policy values */
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	policy->cur = busfreq * max_multiplier;

	result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
	if (result)
		return (result);

	cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);

	return 0;
}


static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
{
	unsigned int i;
	for (i=0; i<8; i++) {
		if (i==max_multiplier)
			powernow_k6_set_state(i);
	}
	cpufreq_frequency_table_put_attr(policy->cpu);
 	return 0;
}

static unsigned int powernow_k6_get(unsigned int cpu)
{
	return busfreq * powernow_k6_get_cpu_multiplier();
}

static struct freq_attr* powernow_k6_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver powernow_k6_driver = {
	.verify 	= powernow_k6_verify,
	.target 	= powernow_k6_target,
	.init		= powernow_k6_cpu_init,
	.exit		= powernow_k6_cpu_exit,
	.get		= powernow_k6_get,
	.name		= "powernow-k6",
	.owner		= THIS_MODULE,
	.attr		= powernow_k6_attr,
};


/**
 * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 *
 *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 * on success.
 */
static int __init powernow_k6_init(void)
{	
	struct cpuinfo_x86      *c = cpu_data;

	if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
		((c->x86_model != 12) && (c->x86_model != 13)))
		return -ENODEV;

	if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
		printk("cpufreq: PowerNow IOPORT region already used.\n");
		return -EIO;
	}

	if (cpufreq_register_driver(&powernow_k6_driver)) {
		release_region (POWERNOW_IOPORT, 16);
		return -EINVAL;
	}

	return 0;
}


/**
 * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 *
 *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 */
static void __exit powernow_k6_exit(void)
{
	cpufreq_unregister_driver(&powernow_k6_driver);
	release_region (POWERNOW_IOPORT, 16);
}


MODULE_AUTHOR ("Arjan van de Ven <arjanv@redhat.com>, Dave Jones <davej@codemonkey.org.uk>, Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION ("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
MODULE_LICENSE ("GPL");

module_init(powernow_k6_init);
module_exit(powernow_k6_exit);