2
* Based on documentation provided by Dave Jones. Thanks!
4
* Licensed under the terms of the GNU GPL License version 2.
6
* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
9
#include <linux/kernel.h>
10
#include <linux/module.h>
11
#include <linux/init.h>
12
#include <linux/cpufreq.h>
13
#include <linux/ioport.h>
14
#include <linux/slab.h>
15
#include <linux/timex.h>
17
#include <linux/delay.h>
22
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
23
#include <linux/acpi.h>
24
#include <acpi/processor.h>
27
#define EPS_BRAND_C7M 0
28
#define EPS_BRAND_C7 1
29
#define EPS_BRAND_EDEN 2
30
#define EPS_BRAND_C3 3
31
#define EPS_BRAND_C7D 4
35
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
38
struct cpufreq_frequency_table freq_table[];
41
static struct eps_cpu_data *eps_cpu[NR_CPUS];
43
/* Module parameters */
44
static int freq_failsafe_off;
45
static int voltage_failsafe_off;
46
static int set_max_voltage;
48
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
49
static int ignore_acpi_limit;
51
static struct acpi_processor_performance *eps_acpi_cpu_perf;
53
/* Minimum necessary to get acpi_processor_get_bios_limit() working */
54
static int eps_acpi_init(void)
56
eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
58
if (!eps_acpi_cpu_perf)
61
if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
63
kfree(eps_acpi_cpu_perf);
64
eps_acpi_cpu_perf = NULL;
68
if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
69
free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
70
kfree(eps_acpi_cpu_perf);
71
eps_acpi_cpu_perf = NULL;
77
static int eps_acpi_exit(struct cpufreq_policy *policy)
79
if (eps_acpi_cpu_perf) {
80
acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
81
free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
82
kfree(eps_acpi_cpu_perf);
83
eps_acpi_cpu_perf = NULL;
89
static unsigned int eps_get(unsigned int cpu)
91
struct eps_cpu_data *centaur;
96
centaur = eps_cpu[cpu];
100
/* Return current frequency */
101
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
102
return centaur->fsb * ((lo >> 8) & 0xff);
105
static int eps_set_state(struct eps_cpu_data *centaur,
109
struct cpufreq_freqs freqs;
114
freqs.old = eps_get(cpu);
115
freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
117
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
119
/* Wait while CPU is busy */
120
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
122
while (lo & ((1 << 16) | (1 << 17))) {
124
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
126
if (unlikely(i > 64)) {
131
/* Set new multiplier and voltage */
132
wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
133
/* Wait until transition end */
137
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
139
if (unlikely(i > 64)) {
143
} while (lo & ((1 << 16) | (1 << 17)));
145
/* Return current frequency */
147
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
148
freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
152
u8 current_multiplier, current_voltage;
154
/* Print voltage and multiplier */
155
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
156
current_voltage = lo & 0xff;
157
printk(KERN_INFO "eps: Current voltage = %dmV\n",
158
current_voltage * 16 + 700);
159
current_multiplier = (lo >> 8) & 0xff;
160
printk(KERN_INFO "eps: Current multiplier = %d\n",
164
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
168
static int eps_target(struct cpufreq_policy *policy,
169
unsigned int target_freq,
170
unsigned int relation)
172
struct eps_cpu_data *centaur;
173
unsigned int newstate = 0;
174
unsigned int cpu = policy->cpu;
175
unsigned int dest_state;
178
if (unlikely(eps_cpu[cpu] == NULL))
180
centaur = eps_cpu[cpu];
182
if (unlikely(cpufreq_frequency_table_target(policy,
183
&eps_cpu[cpu]->freq_table[0],
190
/* Make frequency transition */
191
dest_state = centaur->freq_table[newstate].index & 0xffff;
192
ret = eps_set_state(centaur, cpu, dest_state);
194
printk(KERN_ERR "eps: Timeout!\n");
198
static int eps_verify(struct cpufreq_policy *policy)
200
return cpufreq_frequency_table_verify(policy,
201
&eps_cpu[policy->cpu]->freq_table[0]);
204
static int eps_cpu_init(struct cpufreq_policy *policy)
209
u8 current_multiplier, current_voltage;
210
u8 max_multiplier, max_voltage;
211
u8 min_multiplier, min_voltage;
214
struct eps_cpu_data *centaur;
215
struct cpuinfo_x86 *c = &cpu_data(0);
216
struct cpufreq_frequency_table *f_table;
217
int k, step, voltage;
220
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
224
if (policy->cpu != 0)
228
printk(KERN_INFO "eps: Detected VIA ");
230
switch (c->x86_model) {
232
rdmsr(0x1153, lo, hi);
233
brand = (((lo >> 2) ^ lo) >> 18) & 3;
234
printk(KERN_CONT "Model A ");
237
rdmsr(0x1154, lo, hi);
238
brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
239
printk(KERN_CONT "Model D ");
245
printk(KERN_CONT "C7-M\n");
248
printk(KERN_CONT "C7\n");
251
printk(KERN_CONT "Eden\n");
254
printk(KERN_CONT "C7-D\n");
257
printk(KERN_CONT "C3\n");
261
/* Enable Enhanced PowerSaver */
262
rdmsrl(MSR_IA32_MISC_ENABLE, val);
263
if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
264
val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
265
wrmsrl(MSR_IA32_MISC_ENABLE, val);
266
/* Can be locked at 0 */
267
rdmsrl(MSR_IA32_MISC_ENABLE, val);
268
if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
269
printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
274
/* Print voltage and multiplier */
275
rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
276
current_voltage = lo & 0xff;
277
printk(KERN_INFO "eps: Current voltage = %dmV\n",
278
current_voltage * 16 + 700);
279
current_multiplier = (lo >> 8) & 0xff;
280
printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
283
max_voltage = hi & 0xff;
284
printk(KERN_INFO "eps: Highest voltage = %dmV\n",
285
max_voltage * 16 + 700);
286
max_multiplier = (hi >> 8) & 0xff;
287
printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
288
min_voltage = (hi >> 16) & 0xff;
289
printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
290
min_voltage * 16 + 700);
291
min_multiplier = (hi >> 24) & 0xff;
292
printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
295
if (current_multiplier == 0 || max_multiplier == 0
296
|| min_multiplier == 0)
298
if (current_multiplier > max_multiplier
299
|| max_multiplier <= min_multiplier)
301
if (current_voltage > 0x1f || max_voltage > 0x1f)
303
if (max_voltage < min_voltage
304
|| current_voltage < min_voltage
305
|| current_voltage > max_voltage)
308
/* Check for systems using underclocked CPU */
309
if (!freq_failsafe_off && max_multiplier != current_multiplier) {
310
printk(KERN_INFO "eps: Your processor is running at different "
311
"frequency then its maximum. Aborting.\n");
312
printk(KERN_INFO "eps: You can use freq_failsafe_off option "
313
"to disable this check.\n");
316
if (!voltage_failsafe_off && max_voltage != current_voltage) {
317
printk(KERN_INFO "eps: Your processor is running at different "
318
"voltage then its maximum. Aborting.\n");
319
printk(KERN_INFO "eps: You can use voltage_failsafe_off "
320
"option to disable this check.\n");
325
fsb = cpu_khz / current_multiplier;
327
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
328
/* Check for ACPI processor speed limit */
329
if (!ignore_acpi_limit && !eps_acpi_init()) {
330
if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
331
printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
333
(limit%1000000)/10000);
334
eps_acpi_exit(policy);
335
/* Check if max_multiplier is in BIOS limits */
336
if (limit && max_multiplier * fsb > limit) {
337
printk(KERN_INFO "eps: Aborting.\n");
344
/* Allow user to set lower maximum voltage then that reported
346
if (brand == EPS_BRAND_C7M && set_max_voltage) {
349
/* Change mV to something hardware can use */
350
v = (set_max_voltage - 700) / 16;
351
/* Check if voltage is within limits */
352
if (v >= min_voltage && v <= max_voltage) {
353
printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
359
/* Calc number of p-states supported */
360
if (brand == EPS_BRAND_C7M)
361
states = max_multiplier - min_multiplier + 1;
365
/* Allocate private data and frequency table for current cpu */
366
centaur = kzalloc(sizeof(struct eps_cpu_data)
367
+ (states + 1) * sizeof(struct cpufreq_frequency_table),
371
eps_cpu[0] = centaur;
373
/* Copy basic values */
375
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
376
centaur->bios_limit = limit;
379
/* Fill frequency and MSR value table */
380
f_table = ¢aur->freq_table[0];
381
if (brand != EPS_BRAND_C7M) {
382
f_table[0].frequency = fsb * min_multiplier;
383
f_table[0].index = (min_multiplier << 8) | min_voltage;
384
f_table[1].frequency = fsb * max_multiplier;
385
f_table[1].index = (max_multiplier << 8) | max_voltage;
386
f_table[2].frequency = CPUFREQ_TABLE_END;
389
step = ((max_voltage - min_voltage) * 256)
390
/ (max_multiplier - min_multiplier);
391
for (i = min_multiplier; i <= max_multiplier; i++) {
392
voltage = (k * step) / 256 + min_voltage;
393
f_table[k].frequency = fsb * i;
394
f_table[k].index = (i << 8) | voltage;
397
f_table[k].frequency = CPUFREQ_TABLE_END;
400
policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
401
policy->cur = fsb * current_multiplier;
403
ret = cpufreq_frequency_table_cpuinfo(policy, ¢aur->freq_table[0]);
409
cpufreq_frequency_table_get_attr(¢aur->freq_table[0], policy->cpu);
413
static int eps_cpu_exit(struct cpufreq_policy *policy)
415
unsigned int cpu = policy->cpu;
418
cpufreq_frequency_table_put_attr(policy->cpu);
424
static struct freq_attr *eps_attr[] = {
425
&cpufreq_freq_attr_scaling_available_freqs,
429
static struct cpufreq_driver eps_driver = {
430
.verify = eps_verify,
431
.target = eps_target,
432
.init = eps_cpu_init,
433
.exit = eps_cpu_exit,
435
.name = "e_powersaver",
436
.owner = THIS_MODULE,
440
static int __init eps_init(void)
442
struct cpuinfo_x86 *c = &cpu_data(0);
444
/* This driver will work only on Centaur C7 processors with
445
* Enhanced SpeedStep/PowerSaver registers */
446
if (c->x86_vendor != X86_VENDOR_CENTAUR
447
|| c->x86 != 6 || c->x86_model < 10)
449
if (!cpu_has(c, X86_FEATURE_EST))
452
if (cpufreq_register_driver(&eps_driver))
457
static void __exit eps_exit(void)
459
cpufreq_unregister_driver(&eps_driver);
462
/* Allow user to overclock his machine or to change frequency to higher after
463
* unloading module */
464
module_param(freq_failsafe_off, int, 0644);
465
MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
466
module_param(voltage_failsafe_off, int, 0644);
467
MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
468
#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
469
module_param(ignore_acpi_limit, int, 0644);
470
MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
472
module_param(set_max_voltage, int, 0644);
473
MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
475
MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
476
MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
477
MODULE_LICENSE("GPL");
479
module_init(eps_init);
480
module_exit(eps_exit);