projects/linux·blob master · refs

419 lines · 10.6 KiB

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_obj(*eps_acpi_cpu_perf);
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(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 u64 val;
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 rdmsrq(MSR_IA32_PERF_STATUS, val);
103 return centaur->fsb * ((val >> 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 u64 val;
111 int i;
112
113 /* Wait while CPU is busy */
114 rdmsrq(MSR_IA32_PERF_STATUS, val);
115 i = 0;
116 while (val & ((1 << 16) | (1 << 17))) {
117 udelay(16);
118 rdmsrq(MSR_IA32_PERF_STATUS, val);
119 i++;
120 if (unlikely(i > 64)) {
121 return -ENODEV;
122 }
123 }
124 /* Set new multiplier and voltage */
125 wrmsrq(MSR_IA32_PERF_CTL, dest_state & 0xffff);
126 /* Wait until transition end */
127 i = 0;
128 do {
129 udelay(16);
130 rdmsrq(MSR_IA32_PERF_STATUS, val);
131 i++;
132 if (unlikely(i > 64)) {
133 return -ENODEV;
134 }
135 } while (val & ((1 << 16) | (1 << 17)));
136
137#ifdef DEBUG
138 {
139 u8 current_multiplier, current_voltage;
140
141 /* Print voltage and multiplier */
142 rdmsrq(MSR_IA32_PERF_STATUS, val);
143 current_voltage = val & 0xff;
144 pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
145 current_multiplier = (val >> 8) & 0xff;
146 pr_info("Current multiplier = %d\n", current_multiplier);
147 }
148#endif
149 return 0;
150}
151
152static int eps_target(struct cpufreq_policy *policy, unsigned int index)
153{
154 struct eps_cpu_data *centaur;
155 unsigned int cpu = policy->cpu;
156 unsigned int dest_state;
157 int ret;
158
159 if (unlikely(eps_cpu[cpu] == NULL))
160 return -ENODEV;
161 centaur = eps_cpu[cpu];
162
163 /* Make frequency transition */
164 dest_state = centaur->freq_table[index].driver_data & 0xffff;
165 ret = eps_set_state(centaur, policy, dest_state);
166 if (ret)
167 pr_err("Timeout!\n");
168 return ret;
169}
170
171static int eps_cpu_init(struct cpufreq_policy *policy)
172{
173 unsigned int i;
174 u64 val;
175 u8 current_multiplier, current_voltage;
176 u8 max_multiplier, max_voltage;
177 u8 min_multiplier, min_voltage;
178 u8 brand = 0;
179 u32 fsb;
180 struct eps_cpu_data *centaur;
181 struct cpuinfo_x86 *c = &cpu_data(0);
182 struct cpufreq_frequency_table *f_table;
183 int k, step, voltage;
184 int states;
185#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
186 unsigned int limit;
187#endif
188
189 if (policy->cpu != 0)
190 return -ENODEV;
191
192 /* Check brand */
193 pr_info("Detected VIA ");
194
195 switch (c->x86_model) {
196 case 10:
197 rdmsrq(0x1153, val);
198 brand = (((val >> 2) ^ val) >> 18) & 3;
199 pr_cont("Model A ");
200 break;
201 case 13:
202 rdmsrq(0x1154, val);
203 brand = (((val >> 4) ^ (val >> 2))) & 0x000000ff;
204 pr_cont("Model D ");
205 break;
206 }
207
208 switch (brand) {
209 case EPS_BRAND_C7M:
210 pr_cont("C7-M\n");
211 break;
212 case EPS_BRAND_C7:
213 pr_cont("C7\n");
214 break;
215 case EPS_BRAND_EDEN:
216 pr_cont("Eden\n");
217 break;
218 case EPS_BRAND_C7D:
219 pr_cont("C7-D\n");
220 break;
221 case EPS_BRAND_C3:
222 pr_cont("C3\n");
223 return -ENODEV;
224 }
225 /* Enable Enhanced PowerSaver */
226 rdmsrq(MSR_IA32_MISC_ENABLE, val);
227 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
228 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
229 wrmsrq(MSR_IA32_MISC_ENABLE, val);
230 /* Can be locked at 0 */
231 rdmsrq(MSR_IA32_MISC_ENABLE, val);
232 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
233 pr_info("Can't enable Enhanced PowerSaver\n");
234 return -ENODEV;
235 }
236 }
237
238 /* Print voltage and multiplier */
239 rdmsrq(MSR_IA32_PERF_STATUS, val);
240 current_voltage = val & 0xff;
241 pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
242 current_multiplier = (val >> 8) & 0xff;
243 pr_info("Current multiplier = %d\n", current_multiplier);
244
245 /* Print limits */
246 max_voltage = (val >> 32) & 0xff;
247 pr_info("Highest voltage = %dmV\n", max_voltage * 16 + 700);
248 max_multiplier = (val >> 40) & 0xff;
249 pr_info("Highest multiplier = %d\n", max_multiplier);
250 min_voltage = (val >> 48) & 0xff;
251 pr_info("Lowest voltage = %dmV\n", min_voltage * 16 + 700);
252 min_multiplier = (val >> 56) & 0xff;
253 pr_info("Lowest multiplier = %d\n", min_multiplier);
254
255 /* Sanity checks */
256 if (current_multiplier == 0 || max_multiplier == 0
257 || min_multiplier == 0)
258 return -EINVAL;
259 if (current_multiplier > max_multiplier
260 || max_multiplier <= min_multiplier)
261 return -EINVAL;
262 if (current_voltage > 0x1f || max_voltage > 0x1f)
263 return -EINVAL;
264 if (max_voltage < min_voltage
265 || current_voltage < min_voltage
266 || current_voltage > max_voltage)
267 return -EINVAL;
268
269 /* Check for systems using underclocked CPU */
270 if (!freq_failsafe_off && max_multiplier != current_multiplier) {
271 pr_info("Your processor is running at different frequency then its maximum. Aborting.\n");
272 pr_info("You can use freq_failsafe_off option to disable this check.\n");
273 return -EINVAL;
274 }
275 if (!voltage_failsafe_off && max_voltage != current_voltage) {
276 pr_info("Your processor is running at different voltage then its maximum. Aborting.\n");
277 pr_info("You can use voltage_failsafe_off option to disable this check.\n");
278 return -EINVAL;
279 }
280
281 /* Calc FSB speed */
282 fsb = cpu_khz / current_multiplier;
283
284#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
285 /* Check for ACPI processor speed limit */
286 if (!ignore_acpi_limit && !eps_acpi_init()) {
287 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
288 pr_info("ACPI limit %u.%uGHz\n",
289 limit/1000000,
290 (limit%1000000)/10000);
291 eps_acpi_exit(policy);
292 /* Check if max_multiplier is in BIOS limits */
293 if (limit && max_multiplier * fsb > limit) {
294 pr_info("Aborting\n");
295 return -EINVAL;
296 }
297 }
298 }
299#endif
300
301 /* Allow user to set lower maximum voltage then that reported
302 * by processor */
303 if (brand == EPS_BRAND_C7M && set_max_voltage) {
304 u32 v;
305
306 /* Change mV to something hardware can use */
307 v = (set_max_voltage - 700) / 16;
308 /* Check if voltage is within limits */
309 if (v >= min_voltage && v <= max_voltage) {
310 pr_info("Setting %dmV as maximum\n", v * 16 + 700);
311 max_voltage = v;
312 }
313 }
314
315 /* Calc number of p-states supported */
316 if (brand == EPS_BRAND_C7M)
317 states = max_multiplier - min_multiplier + 1;
318 else
319 states = 2;
320
321 /* Allocate private data and frequency table for current cpu */
322 centaur = kzalloc_flex(*centaur, freq_table, states + 1);
323 if (!centaur)
324 return -ENOMEM;
325 eps_cpu[0] = centaur;
326
327 /* Copy basic values */
328 centaur->fsb = fsb;
329#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
330 centaur->bios_limit = limit;
331#endif
332
333 /* Fill frequency and MSR value table */
334 f_table = &centaur->freq_table[0];
335 if (brand != EPS_BRAND_C7M) {
336 f_table[0].frequency = fsb * min_multiplier;
337 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
338 f_table[1].frequency = fsb * max_multiplier;
339 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
340 f_table[2].frequency = CPUFREQ_TABLE_END;
341 } else {
342 k = 0;
343 step = ((max_voltage - min_voltage) * 256)
344 / (max_multiplier - min_multiplier);
345 for (i = min_multiplier; i <= max_multiplier; i++) {
346 voltage = (k * step) / 256 + min_voltage;
347 f_table[k].frequency = fsb * i;
348 f_table[k].driver_data = (i << 8) | voltage;
349 k++;
350 }
351 f_table[k].frequency = CPUFREQ_TABLE_END;
352 }
353
354 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
355 policy->freq_table = &centaur->freq_table[0];
356
357 return 0;
358}
359
360static void eps_cpu_exit(struct cpufreq_policy *policy)
361{
362 unsigned int cpu = policy->cpu;
363
364 /* Bye */
365 kfree(eps_cpu[cpu]);
366 eps_cpu[cpu] = NULL;
367}
368
369static struct cpufreq_driver eps_driver = {
370 .verify = cpufreq_generic_frequency_table_verify,
371 .target_index = eps_target,
372 .init = eps_cpu_init,
373 .exit = eps_cpu_exit,
374 .get = eps_get,
375 .name = "e_powersaver",
376};
377
378
379/* This driver will work only on Centaur C7 processors with
380 * Enhanced SpeedStep/PowerSaver registers */
381static const struct x86_cpu_id eps_cpu_id[] = {
382 X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 6, X86_FEATURE_EST, NULL),
383 {}
384};
385MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
386
387static int __init eps_init(void)
388{
389 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
390 return -ENODEV;
391 if (cpufreq_register_driver(&eps_driver))
392 return -EINVAL;
393 return 0;
394}
395
396static void __exit eps_exit(void)
397{
398 cpufreq_unregister_driver(&eps_driver);
399}
400
401/* Allow user to overclock his machine or to change frequency to higher after
402 * unloading module */
403module_param(freq_failsafe_off, int, 0644);
404MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
405module_param(voltage_failsafe_off, int, 0644);
406MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
407#if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
408module_param(ignore_acpi_limit, int, 0644);
409MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
410#endif
411module_param(set_max_voltage, int, 0644);
412MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
413
414MODULE_AUTHOR("Rafal Bilski <[email protected]>");
415MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
416MODULE_LICENSE("GPL");
417
418module_init(eps_init);
419module_exit(eps_exit);