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1/*
2 * Based on documentation provided by Dave Jones. Thanks!
3 *
4 * Licensed under the terms of the GNU GPL License version 2.
5 *
6 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
7 */
8
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>
16#include <linux/io.h>
17#include <linux/delay.h>
18
19#include <asm/cpu_device_id.h>
20#include <asm/msr.h>
21#include <asm/tsc.h>
22
23#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
24#include <linux/acpi.h>
25#include <acpi/processor.h>
26#endif
27
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
33
34struct eps_cpu_data {
35 u32 fsb;
36#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
37 u32 bios_limit;
38#endif
39 struct cpufreq_frequency_table freq_table[];
40};
41
42static struct eps_cpu_data *eps_cpu[NR_CPUS];
43
44/* Module parameters */
45static int freq_failsafe_off;
46static int voltage_failsafe_off;
47static int set_max_voltage;
48
49#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
50static int ignore_acpi_limit;
51
52static struct acpi_processor_performance *eps_acpi_cpu_perf;
53
54/* Minimum necessary to get acpi_processor_get_bios_limit() working */
55static int eps_acpi_init(void)
56{
57 eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf),
58 GFP_KERNEL);
59 if (!eps_acpi_cpu_perf)
60 return -ENOMEM;
61
62 if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
63 GFP_KERNEL)) {
64 kfree(eps_acpi_cpu_perf);
65 eps_acpi_cpu_perf = NULL;
66 return -ENOMEM;
67 }
68
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;
73 return -EIO;
74 }
75 return 0;
76}
77
78static int eps_acpi_exit(struct cpufreq_policy *policy)
79{
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;
85 }
86 return 0;
87}
88#endif
89
90static unsigned int eps_get(unsigned int cpu)
91{
92 struct eps_cpu_data *centaur;
93 u32 lo, hi;
94
95 if (cpu)
96 return 0;
97 centaur = eps_cpu[cpu];
98 if (centaur == NULL)
99 return 0;
100
101 /* Return current frequency */
102 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
103 return centaur->fsb * ((lo >> 8) & 0xff);
104}
105
106static int eps_set_state(struct eps_cpu_data *centaur,
107 struct cpufreq_policy *policy,
108 u32 dest_state)
109{
110 u32 lo, hi;
111 int i;
112
113 /* Wait while CPU is busy */
114 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
115 i = 0;
116 while (lo & ((1 << 16) | (1 << 17))) {
117 udelay(16);
118 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
119 i++;
120 if (unlikely(i > 64)) {
121 return -ENODEV;
122 }
123 }
124 /* Set new multiplier and voltage */
125 wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
126 /* Wait until transition end */
127 i = 0;
128 do {
129 udelay(16);
130 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
131 i++;
132 if (unlikely(i > 64)) {
133 return -ENODEV;
134 }
135 } while (lo & ((1 << 16) | (1 << 17)));
136
137#ifdef DEBUG
138 {
139 u8 current_multiplier, current_voltage;
140
141 /* Print voltage and multiplier */
142 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
143 current_voltage = lo & 0xff;
144 printk(KERN_INFO "eps: Current voltage = %dmV\n",
145 current_voltage * 16 + 700);
146 current_multiplier = (lo >> 8) & 0xff;
147 printk(KERN_INFO "eps: Current multiplier = %d\n",
148 current_multiplier);
149 }
150#endif
151 return 0;
152}
153
154static int eps_target(struct cpufreq_policy *policy, unsigned int index)
155{
156 struct eps_cpu_data *centaur;
157 unsigned int cpu = policy->cpu;
158 unsigned int dest_state;
159 int ret;
160
161 if (unlikely(eps_cpu[cpu] == NULL))
162 return -ENODEV;
163 centaur = eps_cpu[cpu];
164
165 /* Make frequency transition */
166 dest_state = centaur->freq_table[index].driver_data & 0xffff;
167 ret = eps_set_state(centaur, policy, dest_state);
168 if (ret)
169 printk(KERN_ERR "eps: Timeout!\n");
170 return ret;
171}
172
173static int eps_cpu_init(struct cpufreq_policy *policy)
174{
175 unsigned int i;
176 u32 lo, hi;
177 u64 val;
178 u8 current_multiplier, current_voltage;
179 u8 max_multiplier, max_voltage;
180 u8 min_multiplier, min_voltage;
181 u8 brand = 0;
182 u32 fsb;
183 struct eps_cpu_data *centaur;
184 struct cpuinfo_x86 *c = &cpu_data(0);
185 struct cpufreq_frequency_table *f_table;
186 int k, step, voltage;
187 int ret;
188 int states;
189#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
190 unsigned int limit;
191#endif
192
193 if (policy->cpu != 0)
194 return -ENODEV;
195
196 /* Check brand */
197 printk(KERN_INFO "eps: Detected VIA ");
198
199 switch (c->x86_model) {
200 case 10:
201 rdmsr(0x1153, lo, hi);
202 brand = (((lo >> 2) ^ lo) >> 18) & 3;
203 printk(KERN_CONT "Model A ");
204 break;
205 case 13:
206 rdmsr(0x1154, lo, hi);
207 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
208 printk(KERN_CONT "Model D ");
209 break;
210 }
211
212 switch (brand) {
213 case EPS_BRAND_C7M:
214 printk(KERN_CONT "C7-M\n");
215 break;
216 case EPS_BRAND_C7:
217 printk(KERN_CONT "C7\n");
218 break;
219 case EPS_BRAND_EDEN:
220 printk(KERN_CONT "Eden\n");
221 break;
222 case EPS_BRAND_C7D:
223 printk(KERN_CONT "C7-D\n");
224 break;
225 case EPS_BRAND_C3:
226 printk(KERN_CONT "C3\n");
227 return -ENODEV;
228 break;
229 }
230 /* Enable Enhanced PowerSaver */
231 rdmsrl(MSR_IA32_MISC_ENABLE, val);
232 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
233 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
234 wrmsrl(MSR_IA32_MISC_ENABLE, val);
235 /* Can be locked at 0 */
236 rdmsrl(MSR_IA32_MISC_ENABLE, val);
237 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
238 printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
239 return -ENODEV;
240 }
241 }
242
243 /* Print voltage and multiplier */
244 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
245 current_voltage = lo & 0xff;
246 printk(KERN_INFO "eps: Current voltage = %dmV\n",
247 current_voltage * 16 + 700);
248 current_multiplier = (lo >> 8) & 0xff;
249 printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
250
251 /* Print limits */
252 max_voltage = hi & 0xff;
253 printk(KERN_INFO "eps: Highest voltage = %dmV\n",
254 max_voltage * 16 + 700);
255 max_multiplier = (hi >> 8) & 0xff;
256 printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
257 min_voltage = (hi >> 16) & 0xff;
258 printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
259 min_voltage * 16 + 700);
260 min_multiplier = (hi >> 24) & 0xff;
261 printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
262
263 /* Sanity checks */
264 if (current_multiplier == 0 || max_multiplier == 0
265 || min_multiplier == 0)
266 return -EINVAL;
267 if (current_multiplier > max_multiplier
268 || max_multiplier <= min_multiplier)
269 return -EINVAL;
270 if (current_voltage > 0x1f || max_voltage > 0x1f)
271 return -EINVAL;
272 if (max_voltage < min_voltage
273 || current_voltage < min_voltage
274 || current_voltage > max_voltage)
275 return -EINVAL;
276
277 /* Check for systems using underclocked CPU */
278 if (!freq_failsafe_off && max_multiplier != current_multiplier) {
279 printk(KERN_INFO "eps: Your processor is running at different "
280 "frequency then its maximum. Aborting.\n");
281 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
282 "to disable this check.\n");
283 return -EINVAL;
284 }
285 if (!voltage_failsafe_off && max_voltage != current_voltage) {
286 printk(KERN_INFO "eps: Your processor is running at different "
287 "voltage then its maximum. Aborting.\n");
288 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
289 "option to disable this check.\n");
290 return -EINVAL;
291 }
292
293 /* Calc FSB speed */
294 fsb = cpu_khz / current_multiplier;
295
296#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
297 /* Check for ACPI processor speed limit */
298 if (!ignore_acpi_limit && !eps_acpi_init()) {
299 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
300 printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
301 limit/1000000,
302 (limit%1000000)/10000);
303 eps_acpi_exit(policy);
304 /* Check if max_multiplier is in BIOS limits */
305 if (limit && max_multiplier * fsb > limit) {
306 printk(KERN_INFO "eps: Aborting.\n");
307 return -EINVAL;
308 }
309 }
310 }
311#endif
312
313 /* Allow user to set lower maximum voltage then that reported
314 * by processor */
315 if (brand == EPS_BRAND_C7M && set_max_voltage) {
316 u32 v;
317
318 /* Change mV to something hardware can use */
319 v = (set_max_voltage - 700) / 16;
320 /* Check if voltage is within limits */
321 if (v >= min_voltage && v <= max_voltage) {
322 printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
323 v * 16 + 700);
324 max_voltage = v;
325 }
326 }
327
328 /* Calc number of p-states supported */
329 if (brand == EPS_BRAND_C7M)
330 states = max_multiplier - min_multiplier + 1;
331 else
332 states = 2;
333
334 /* Allocate private data and frequency table for current cpu */
335 centaur = kzalloc(sizeof(*centaur)
336 + (states + 1) * sizeof(struct cpufreq_frequency_table),
337 GFP_KERNEL);
338 if (!centaur)
339 return -ENOMEM;
340 eps_cpu[0] = centaur;
341
342 /* Copy basic values */
343 centaur->fsb = fsb;
344#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
345 centaur->bios_limit = limit;
346#endif
347
348 /* Fill frequency and MSR value table */
349 f_table = ¢aur->freq_table[0];
350 if (brand != EPS_BRAND_C7M) {
351 f_table[0].frequency = fsb * min_multiplier;
352 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
353 f_table[1].frequency = fsb * max_multiplier;
354 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
355 f_table[2].frequency = CPUFREQ_TABLE_END;
356 } else {
357 k = 0;
358 step = ((max_voltage - min_voltage) * 256)
359 / (max_multiplier - min_multiplier);
360 for (i = min_multiplier; i <= max_multiplier; i++) {
361 voltage = (k * step) / 256 + min_voltage;
362 f_table[k].frequency = fsb * i;
363 f_table[k].driver_data = (i << 8) | voltage;
364 k++;
365 }
366 f_table[k].frequency = CPUFREQ_TABLE_END;
367 }
368
369 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
370
371 ret = cpufreq_table_validate_and_show(policy, ¢aur->freq_table[0]);
372 if (ret) {
373 kfree(centaur);
374 return ret;
375 }
376
377 return 0;
378}
379
380static int eps_cpu_exit(struct cpufreq_policy *policy)
381{
382 unsigned int cpu = policy->cpu;
383
384 /* Bye */
385 kfree(eps_cpu[cpu]);
386 eps_cpu[cpu] = NULL;
387 return 0;
388}
389
390static struct cpufreq_driver eps_driver = {
391 .verify = cpufreq_generic_frequency_table_verify,
392 .target_index = eps_target,
393 .init = eps_cpu_init,
394 .exit = eps_cpu_exit,
395 .get = eps_get,
396 .name = "e_powersaver",
397 .attr = cpufreq_generic_attr,
398};
399
400
401/* This driver will work only on Centaur C7 processors with
402 * Enhanced SpeedStep/PowerSaver registers */
403static const struct x86_cpu_id eps_cpu_id[] = {
404 { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
405 {}
406};
407MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
408
409static int __init eps_init(void)
410{
411 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
412 return -ENODEV;
413 if (cpufreq_register_driver(&eps_driver))
414 return -EINVAL;
415 return 0;
416}
417
418static void __exit eps_exit(void)
419{
420 cpufreq_unregister_driver(&eps_driver);
421}
422
423/* Allow user to overclock his machine or to change frequency to higher after
424 * unloading module */
425module_param(freq_failsafe_off, int, 0644);
426MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
427module_param(voltage_failsafe_off, int, 0644);
428MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
429#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
430module_param(ignore_acpi_limit, int, 0644);
431MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
432#endif
433module_param(set_max_voltage, int, 0644);
434MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
435
436MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
437MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
438MODULE_LICENSE("GPL");
439
440module_init(eps_init);
441module_exit(eps_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Based on documentation provided by Dave Jones. Thanks!
4 *
5 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/cpufreq.h>
14#include <linux/ioport.h>
15#include <linux/slab.h>
16#include <linux/timex.h>
17#include <linux/io.h>
18#include <linux/delay.h>
19
20#include <asm/cpu_device_id.h>
21#include <asm/msr.h>
22#include <asm/tsc.h>
23
24#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
25#include <linux/acpi.h>
26#include <acpi/processor.h>
27#endif
28
29#define EPS_BRAND_C7M 0
30#define EPS_BRAND_C7 1
31#define EPS_BRAND_EDEN 2
32#define EPS_BRAND_C3 3
33#define EPS_BRAND_C7D 4
34
35struct eps_cpu_data {
36 u32 fsb;
37#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
38 u32 bios_limit;
39#endif
40 struct cpufreq_frequency_table freq_table[];
41};
42
43static struct eps_cpu_data *eps_cpu[NR_CPUS];
44
45/* Module parameters */
46static int freq_failsafe_off;
47static int voltage_failsafe_off;
48static int set_max_voltage;
49
50#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
51static int ignore_acpi_limit;
52
53static struct acpi_processor_performance *eps_acpi_cpu_perf;
54
55/* Minimum necessary to get acpi_processor_get_bios_limit() working */
56static int eps_acpi_init(void)
57{
58 eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf),
59 GFP_KERNEL);
60 if (!eps_acpi_cpu_perf)
61 return -ENOMEM;
62
63 if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
64 GFP_KERNEL)) {
65 kfree(eps_acpi_cpu_perf);
66 eps_acpi_cpu_perf = NULL;
67 return -ENOMEM;
68 }
69
70 if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
71 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
72 kfree(eps_acpi_cpu_perf);
73 eps_acpi_cpu_perf = NULL;
74 return -EIO;
75 }
76 return 0;
77}
78
79static int eps_acpi_exit(struct cpufreq_policy *policy)
80{
81 if (eps_acpi_cpu_perf) {
82 acpi_processor_unregister_performance(0);
83 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
84 kfree(eps_acpi_cpu_perf);
85 eps_acpi_cpu_perf = NULL;
86 }
87 return 0;
88}
89#endif
90
91static unsigned int eps_get(unsigned int cpu)
92{
93 struct eps_cpu_data *centaur;
94 u32 lo, hi;
95
96 if (cpu)
97 return 0;
98 centaur = eps_cpu[cpu];
99 if (centaur == NULL)
100 return 0;
101
102 /* Return current frequency */
103 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
104 return centaur->fsb * ((lo >> 8) & 0xff);
105}
106
107static int eps_set_state(struct eps_cpu_data *centaur,
108 struct cpufreq_policy *policy,
109 u32 dest_state)
110{
111 u32 lo, hi;
112 int i;
113
114 /* Wait while CPU is busy */
115 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
116 i = 0;
117 while (lo & ((1 << 16) | (1 << 17))) {
118 udelay(16);
119 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
120 i++;
121 if (unlikely(i > 64)) {
122 return -ENODEV;
123 }
124 }
125 /* Set new multiplier and voltage */
126 wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
127 /* Wait until transition end */
128 i = 0;
129 do {
130 udelay(16);
131 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
132 i++;
133 if (unlikely(i > 64)) {
134 return -ENODEV;
135 }
136 } while (lo & ((1 << 16) | (1 << 17)));
137
138#ifdef DEBUG
139 {
140 u8 current_multiplier, current_voltage;
141
142 /* Print voltage and multiplier */
143 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
144 current_voltage = lo & 0xff;
145 pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
146 current_multiplier = (lo >> 8) & 0xff;
147 pr_info("Current multiplier = %d\n", current_multiplier);
148 }
149#endif
150 return 0;
151}
152
153static int eps_target(struct cpufreq_policy *policy, unsigned int index)
154{
155 struct eps_cpu_data *centaur;
156 unsigned int cpu = policy->cpu;
157 unsigned int dest_state;
158 int ret;
159
160 if (unlikely(eps_cpu[cpu] == NULL))
161 return -ENODEV;
162 centaur = eps_cpu[cpu];
163
164 /* Make frequency transition */
165 dest_state = centaur->freq_table[index].driver_data & 0xffff;
166 ret = eps_set_state(centaur, policy, dest_state);
167 if (ret)
168 pr_err("Timeout!\n");
169 return ret;
170}
171
172static int eps_cpu_init(struct cpufreq_policy *policy)
173{
174 unsigned int i;
175 u32 lo, hi;
176 u64 val;
177 u8 current_multiplier, current_voltage;
178 u8 max_multiplier, max_voltage;
179 u8 min_multiplier, min_voltage;
180 u8 brand = 0;
181 u32 fsb;
182 struct eps_cpu_data *centaur;
183 struct cpuinfo_x86 *c = &cpu_data(0);
184 struct cpufreq_frequency_table *f_table;
185 int k, step, voltage;
186 int states;
187#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
188 unsigned int limit;
189#endif
190
191 if (policy->cpu != 0)
192 return -ENODEV;
193
194 /* Check brand */
195 pr_info("Detected VIA ");
196
197 switch (c->x86_model) {
198 case 10:
199 rdmsr(0x1153, lo, hi);
200 brand = (((lo >> 2) ^ lo) >> 18) & 3;
201 pr_cont("Model A ");
202 break;
203 case 13:
204 rdmsr(0x1154, lo, hi);
205 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
206 pr_cont("Model D ");
207 break;
208 }
209
210 switch (brand) {
211 case EPS_BRAND_C7M:
212 pr_cont("C7-M\n");
213 break;
214 case EPS_BRAND_C7:
215 pr_cont("C7\n");
216 break;
217 case EPS_BRAND_EDEN:
218 pr_cont("Eden\n");
219 break;
220 case EPS_BRAND_C7D:
221 pr_cont("C7-D\n");
222 break;
223 case EPS_BRAND_C3:
224 pr_cont("C3\n");
225 return -ENODEV;
226 }
227 /* Enable Enhanced PowerSaver */
228 rdmsrl(MSR_IA32_MISC_ENABLE, val);
229 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
230 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
231 wrmsrl(MSR_IA32_MISC_ENABLE, val);
232 /* Can be locked at 0 */
233 rdmsrl(MSR_IA32_MISC_ENABLE, val);
234 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
235 pr_info("Can't enable Enhanced PowerSaver\n");
236 return -ENODEV;
237 }
238 }
239
240 /* Print voltage and multiplier */
241 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
242 current_voltage = lo & 0xff;
243 pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
244 current_multiplier = (lo >> 8) & 0xff;
245 pr_info("Current multiplier = %d\n", current_multiplier);
246
247 /* Print limits */
248 max_voltage = hi & 0xff;
249 pr_info("Highest voltage = %dmV\n", max_voltage * 16 + 700);
250 max_multiplier = (hi >> 8) & 0xff;
251 pr_info("Highest multiplier = %d\n", max_multiplier);
252 min_voltage = (hi >> 16) & 0xff;
253 pr_info("Lowest voltage = %dmV\n", min_voltage * 16 + 700);
254 min_multiplier = (hi >> 24) & 0xff;
255 pr_info("Lowest multiplier = %d\n", min_multiplier);
256
257 /* Sanity checks */
258 if (current_multiplier == 0 || max_multiplier == 0
259 || min_multiplier == 0)
260 return -EINVAL;
261 if (current_multiplier > max_multiplier
262 || max_multiplier <= min_multiplier)
263 return -EINVAL;
264 if (current_voltage > 0x1f || max_voltage > 0x1f)
265 return -EINVAL;
266 if (max_voltage < min_voltage
267 || current_voltage < min_voltage
268 || current_voltage > max_voltage)
269 return -EINVAL;
270
271 /* Check for systems using underclocked CPU */
272 if (!freq_failsafe_off && max_multiplier != current_multiplier) {
273 pr_info("Your processor is running at different frequency then its maximum. Aborting.\n");
274 pr_info("You can use freq_failsafe_off option to disable this check.\n");
275 return -EINVAL;
276 }
277 if (!voltage_failsafe_off && max_voltage != current_voltage) {
278 pr_info("Your processor is running at different voltage then its maximum. Aborting.\n");
279 pr_info("You can use voltage_failsafe_off option to disable this check.\n");
280 return -EINVAL;
281 }
282
283 /* Calc FSB speed */
284 fsb = cpu_khz / current_multiplier;
285
286#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
287 /* Check for ACPI processor speed limit */
288 if (!ignore_acpi_limit && !eps_acpi_init()) {
289 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
290 pr_info("ACPI limit %u.%uGHz\n",
291 limit/1000000,
292 (limit%1000000)/10000);
293 eps_acpi_exit(policy);
294 /* Check if max_multiplier is in BIOS limits */
295 if (limit && max_multiplier * fsb > limit) {
296 pr_info("Aborting\n");
297 return -EINVAL;
298 }
299 }
300 }
301#endif
302
303 /* Allow user to set lower maximum voltage then that reported
304 * by processor */
305 if (brand == EPS_BRAND_C7M && set_max_voltage) {
306 u32 v;
307
308 /* Change mV to something hardware can use */
309 v = (set_max_voltage - 700) / 16;
310 /* Check if voltage is within limits */
311 if (v >= min_voltage && v <= max_voltage) {
312 pr_info("Setting %dmV as maximum\n", v * 16 + 700);
313 max_voltage = v;
314 }
315 }
316
317 /* Calc number of p-states supported */
318 if (brand == EPS_BRAND_C7M)
319 states = max_multiplier - min_multiplier + 1;
320 else
321 states = 2;
322
323 /* Allocate private data and frequency table for current cpu */
324 centaur = kzalloc(struct_size(centaur, freq_table, states + 1),
325 GFP_KERNEL);
326 if (!centaur)
327 return -ENOMEM;
328 eps_cpu[0] = centaur;
329
330 /* Copy basic values */
331 centaur->fsb = fsb;
332#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
333 centaur->bios_limit = limit;
334#endif
335
336 /* Fill frequency and MSR value table */
337 f_table = ¢aur->freq_table[0];
338 if (brand != EPS_BRAND_C7M) {
339 f_table[0].frequency = fsb * min_multiplier;
340 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
341 f_table[1].frequency = fsb * max_multiplier;
342 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
343 f_table[2].frequency = CPUFREQ_TABLE_END;
344 } else {
345 k = 0;
346 step = ((max_voltage - min_voltage) * 256)
347 / (max_multiplier - min_multiplier);
348 for (i = min_multiplier; i <= max_multiplier; i++) {
349 voltage = (k * step) / 256 + min_voltage;
350 f_table[k].frequency = fsb * i;
351 f_table[k].driver_data = (i << 8) | voltage;
352 k++;
353 }
354 f_table[k].frequency = CPUFREQ_TABLE_END;
355 }
356
357 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
358 policy->freq_table = ¢aur->freq_table[0];
359
360 return 0;
361}
362
363static void eps_cpu_exit(struct cpufreq_policy *policy)
364{
365 unsigned int cpu = policy->cpu;
366
367 /* Bye */
368 kfree(eps_cpu[cpu]);
369 eps_cpu[cpu] = NULL;
370}
371
372static struct cpufreq_driver eps_driver = {
373 .verify = cpufreq_generic_frequency_table_verify,
374 .target_index = eps_target,
375 .init = eps_cpu_init,
376 .exit = eps_cpu_exit,
377 .get = eps_get,
378 .name = "e_powersaver",
379 .attr = cpufreq_generic_attr,
380};
381
382
383/* This driver will work only on Centaur C7 processors with
384 * Enhanced SpeedStep/PowerSaver registers */
385static const struct x86_cpu_id eps_cpu_id[] = {
386 X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 6, X86_FEATURE_EST, NULL),
387 {}
388};
389MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
390
391static int __init eps_init(void)
392{
393 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
394 return -ENODEV;
395 if (cpufreq_register_driver(&eps_driver))
396 return -EINVAL;
397 return 0;
398}
399
400static void __exit eps_exit(void)
401{
402 cpufreq_unregister_driver(&eps_driver);
403}
404
405/* Allow user to overclock his machine or to change frequency to higher after
406 * unloading module */
407module_param(freq_failsafe_off, int, 0644);
408MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
409module_param(voltage_failsafe_off, int, 0644);
410MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
411#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
412module_param(ignore_acpi_limit, int, 0644);
413MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
414#endif
415module_param(set_max_voltage, int, 0644);
416MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
417
418MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
419MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
420MODULE_LICENSE("GPL");
421
422module_init(eps_init);
423module_exit(eps_exit);