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>
19 #include <asm/cpu_device_id.h>
23 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
24 #include <linux/acpi.h>
25 #include <acpi/processor.h>
28 #define EPS_BRAND_C7M 0
29 #define EPS_BRAND_C7 1
30 #define EPS_BRAND_EDEN 2
31 #define EPS_BRAND_C3 3
32 #define EPS_BRAND_C7D 4
36 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
39 struct cpufreq_frequency_table freq_table[];
42 static struct eps_cpu_data *eps_cpu[NR_CPUS];
44 /* Module parameters */
45 static int freq_failsafe_off;
46 static int voltage_failsafe_off;
47 static int set_max_voltage;
49 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
50 static int ignore_acpi_limit;
52 static struct acpi_processor_performance *eps_acpi_cpu_perf;
54 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
55 static int eps_acpi_init(void)
57 eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
59 if (!eps_acpi_cpu_perf)
62 if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
64 kfree(eps_acpi_cpu_perf);
65 eps_acpi_cpu_perf = NULL;
69 if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
70 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
71 kfree(eps_acpi_cpu_perf);
72 eps_acpi_cpu_perf = NULL;
78 static int eps_acpi_exit(struct cpufreq_policy *policy)
80 if (eps_acpi_cpu_perf) {
81 acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
82 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
83 kfree(eps_acpi_cpu_perf);
84 eps_acpi_cpu_perf = NULL;
90 static unsigned int eps_get(unsigned int cpu)
92 struct eps_cpu_data *centaur;
97 centaur = eps_cpu[cpu];
101 /* Return current frequency */
102 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
103 return centaur->fsb * ((lo >> 8) & 0xff);
106 static int eps_set_state(struct eps_cpu_data *centaur,
107 struct cpufreq_policy *policy,
110 struct cpufreq_freqs freqs;
115 freqs.old = eps_get(policy->cpu);
116 freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
117 cpufreq_notify_transition(policy, &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(policy, &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, policy, 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,
441 /* This driver will work only on Centaur C7 processors with
442 * Enhanced SpeedStep/PowerSaver registers */
443 static const struct x86_cpu_id eps_cpu_id[] = {
444 { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
447 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
449 static int __init eps_init(void)
451 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
453 if (cpufreq_register_driver(&eps_driver))
458 static void __exit eps_exit(void)
460 cpufreq_unregister_driver(&eps_driver);
463 /* Allow user to overclock his machine or to change frequency to higher after
464 * unloading module */
465 module_param(freq_failsafe_off, int, 0644);
466 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
467 module_param(voltage_failsafe_off, int, 0644);
468 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
469 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
470 module_param(ignore_acpi_limit, int, 0644);
471 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
473 module_param(set_max_voltage, int, 0644);
474 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
476 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
477 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
478 MODULE_LICENSE("GPL");
480 module_init(eps_init);
481 module_exit(eps_exit);