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 34 struct 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 42 static struct eps_cpu_data *eps_cpu[NR_CPUS]; 43 44 /* Module parameters */ 45 static int freq_failsafe_off; 46 static int voltage_failsafe_off; 47 static int set_max_voltage; 48 49 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 50 static int ignore_acpi_limit; 51 52 static struct acpi_processor_performance *eps_acpi_cpu_perf; 53 54 /* Minimum necessary to get acpi_processor_get_bios_limit() working */ 55 static int eps_acpi_init(void) 56 { 57 eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance), 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 78 static 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 90 static 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 } 105 106 static int eps_set_state(struct eps_cpu_data *centaur, 107 unsigned int cpu, 108 u32 dest_state) 109 { 110 struct cpufreq_freqs freqs; 111 u32 lo, hi; 112 int err = 0; 113 int i; 114 115 freqs.old = eps_get(cpu); 116 freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff); 117 freqs.cpu = cpu; 118 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 119 120 /* Wait while CPU is busy */ 121 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 122 i = 0; 123 while (lo & ((1 << 16) | (1 << 17))) { 124 udelay(16); 125 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 126 i++; 127 if (unlikely(i > 64)) { 128 err = -ENODEV; 129 goto postchange; 130 } 131 } 132 /* Set new multiplier and voltage */ 133 wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0); 134 /* Wait until transition end */ 135 i = 0; 136 do { 137 udelay(16); 138 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 139 i++; 140 if (unlikely(i > 64)) { 141 err = -ENODEV; 142 goto postchange; 143 } 144 } while (lo & ((1 << 16) | (1 << 17))); 145 146 /* Return current frequency */ 147 postchange: 148 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 149 freqs.new = centaur->fsb * ((lo >> 8) & 0xff); 150 151 #ifdef DEBUG 152 { 153 u8 current_multiplier, current_voltage; 154 155 /* Print voltage and multiplier */ 156 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 157 current_voltage = lo & 0xff; 158 printk(KERN_INFO "eps: Current voltage = %dmV\n", 159 current_voltage * 16 + 700); 160 current_multiplier = (lo >> 8) & 0xff; 161 printk(KERN_INFO "eps: Current multiplier = %d\n", 162 current_multiplier); 163 } 164 #endif 165 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 166 return err; 167 } 168 169 static int eps_target(struct cpufreq_policy *policy, 170 unsigned int target_freq, 171 unsigned int relation) 172 { 173 struct eps_cpu_data *centaur; 174 unsigned int newstate = 0; 175 unsigned int cpu = policy->cpu; 176 unsigned int dest_state; 177 int ret; 178 179 if (unlikely(eps_cpu[cpu] == NULL)) 180 return -ENODEV; 181 centaur = eps_cpu[cpu]; 182 183 if (unlikely(cpufreq_frequency_table_target(policy, 184 &eps_cpu[cpu]->freq_table[0], 185 target_freq, 186 relation, 187 &newstate))) { 188 return -EINVAL; 189 } 190 191 /* Make frequency transition */ 192 dest_state = centaur->freq_table[newstate].index & 0xffff; 193 ret = eps_set_state(centaur, cpu, dest_state); 194 if (ret) 195 printk(KERN_ERR "eps: Timeout!\n"); 196 return ret; 197 } 198 199 static int eps_verify(struct cpufreq_policy *policy) 200 { 201 return cpufreq_frequency_table_verify(policy, 202 &eps_cpu[policy->cpu]->freq_table[0]); 203 } 204 205 static int eps_cpu_init(struct cpufreq_policy *policy) 206 { 207 unsigned int i; 208 u32 lo, hi; 209 u64 val; 210 u8 current_multiplier, current_voltage; 211 u8 max_multiplier, max_voltage; 212 u8 min_multiplier, min_voltage; 213 u8 brand = 0; 214 u32 fsb; 215 struct eps_cpu_data *centaur; 216 struct cpuinfo_x86 *c = &cpu_data(0); 217 struct cpufreq_frequency_table *f_table; 218 int k, step, voltage; 219 int ret; 220 int states; 221 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 222 unsigned int limit; 223 #endif 224 225 if (policy->cpu != 0) 226 return -ENODEV; 227 228 /* Check brand */ 229 printk(KERN_INFO "eps: Detected VIA "); 230 231 switch (c->x86_model) { 232 case 10: 233 rdmsr(0x1153, lo, hi); 234 brand = (((lo >> 2) ^ lo) >> 18) & 3; 235 printk(KERN_CONT "Model A "); 236 break; 237 case 13: 238 rdmsr(0x1154, lo, hi); 239 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff; 240 printk(KERN_CONT "Model D "); 241 break; 242 } 243 244 switch (brand) { 245 case EPS_BRAND_C7M: 246 printk(KERN_CONT "C7-M\n"); 247 break; 248 case EPS_BRAND_C7: 249 printk(KERN_CONT "C7\n"); 250 break; 251 case EPS_BRAND_EDEN: 252 printk(KERN_CONT "Eden\n"); 253 break; 254 case EPS_BRAND_C7D: 255 printk(KERN_CONT "C7-D\n"); 256 break; 257 case EPS_BRAND_C3: 258 printk(KERN_CONT "C3\n"); 259 return -ENODEV; 260 break; 261 } 262 /* Enable Enhanced PowerSaver */ 263 rdmsrl(MSR_IA32_MISC_ENABLE, val); 264 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 265 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; 266 wrmsrl(MSR_IA32_MISC_ENABLE, val); 267 /* Can be locked at 0 */ 268 rdmsrl(MSR_IA32_MISC_ENABLE, val); 269 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 270 printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n"); 271 return -ENODEV; 272 } 273 } 274 275 /* Print voltage and multiplier */ 276 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 277 current_voltage = lo & 0xff; 278 printk(KERN_INFO "eps: Current voltage = %dmV\n", 279 current_voltage * 16 + 700); 280 current_multiplier = (lo >> 8) & 0xff; 281 printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier); 282 283 /* Print limits */ 284 max_voltage = hi & 0xff; 285 printk(KERN_INFO "eps: Highest voltage = %dmV\n", 286 max_voltage * 16 + 700); 287 max_multiplier = (hi >> 8) & 0xff; 288 printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier); 289 min_voltage = (hi >> 16) & 0xff; 290 printk(KERN_INFO "eps: Lowest voltage = %dmV\n", 291 min_voltage * 16 + 700); 292 min_multiplier = (hi >> 24) & 0xff; 293 printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier); 294 295 /* Sanity checks */ 296 if (current_multiplier == 0 || max_multiplier == 0 297 || min_multiplier == 0) 298 return -EINVAL; 299 if (current_multiplier > max_multiplier 300 || max_multiplier <= min_multiplier) 301 return -EINVAL; 302 if (current_voltage > 0x1f || max_voltage > 0x1f) 303 return -EINVAL; 304 if (max_voltage < min_voltage 305 || current_voltage < min_voltage 306 || current_voltage > max_voltage) 307 return -EINVAL; 308 309 /* Check for systems using underclocked CPU */ 310 if (!freq_failsafe_off && max_multiplier != current_multiplier) { 311 printk(KERN_INFO "eps: Your processor is running at different " 312 "frequency then its maximum. Aborting.\n"); 313 printk(KERN_INFO "eps: You can use freq_failsafe_off option " 314 "to disable this check.\n"); 315 return -EINVAL; 316 } 317 if (!voltage_failsafe_off && max_voltage != current_voltage) { 318 printk(KERN_INFO "eps: Your processor is running at different " 319 "voltage then its maximum. Aborting.\n"); 320 printk(KERN_INFO "eps: You can use voltage_failsafe_off " 321 "option to disable this check.\n"); 322 return -EINVAL; 323 } 324 325 /* Calc FSB speed */ 326 fsb = cpu_khz / current_multiplier; 327 328 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 329 /* Check for ACPI processor speed limit */ 330 if (!ignore_acpi_limit && !eps_acpi_init()) { 331 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) { 332 printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n", 333 limit/1000000, 334 (limit%1000000)/10000); 335 eps_acpi_exit(policy); 336 /* Check if max_multiplier is in BIOS limits */ 337 if (limit && max_multiplier * fsb > limit) { 338 printk(KERN_INFO "eps: Aborting.\n"); 339 return -EINVAL; 340 } 341 } 342 } 343 #endif 344 345 /* Allow user to set lower maximum voltage then that reported 346 * by processor */ 347 if (brand == EPS_BRAND_C7M && set_max_voltage) { 348 u32 v; 349 350 /* Change mV to something hardware can use */ 351 v = (set_max_voltage - 700) / 16; 352 /* Check if voltage is within limits */ 353 if (v >= min_voltage && v <= max_voltage) { 354 printk(KERN_INFO "eps: Setting %dmV as maximum.\n", 355 v * 16 + 700); 356 max_voltage = v; 357 } 358 } 359 360 /* Calc number of p-states supported */ 361 if (brand == EPS_BRAND_C7M) 362 states = max_multiplier - min_multiplier + 1; 363 else 364 states = 2; 365 366 /* Allocate private data and frequency table for current cpu */ 367 centaur = kzalloc(sizeof(struct eps_cpu_data) 368 + (states + 1) * sizeof(struct cpufreq_frequency_table), 369 GFP_KERNEL); 370 if (!centaur) 371 return -ENOMEM; 372 eps_cpu[0] = centaur; 373 374 /* Copy basic values */ 375 centaur->fsb = fsb; 376 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 377 centaur->bios_limit = limit; 378 #endif 379 380 /* Fill frequency and MSR value table */ 381 f_table = ¢aur->freq_table[0]; 382 if (brand != EPS_BRAND_C7M) { 383 f_table[0].frequency = fsb * min_multiplier; 384 f_table[0].index = (min_multiplier << 8) | min_voltage; 385 f_table[1].frequency = fsb * max_multiplier; 386 f_table[1].index = (max_multiplier << 8) | max_voltage; 387 f_table[2].frequency = CPUFREQ_TABLE_END; 388 } else { 389 k = 0; 390 step = ((max_voltage - min_voltage) * 256) 391 / (max_multiplier - min_multiplier); 392 for (i = min_multiplier; i <= max_multiplier; i++) { 393 voltage = (k * step) / 256 + min_voltage; 394 f_table[k].frequency = fsb * i; 395 f_table[k].index = (i << 8) | voltage; 396 k++; 397 } 398 f_table[k].frequency = CPUFREQ_TABLE_END; 399 } 400 401 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */ 402 policy->cur = fsb * current_multiplier; 403 404 ret = cpufreq_frequency_table_cpuinfo(policy, ¢aur->freq_table[0]); 405 if (ret) { 406 kfree(centaur); 407 return ret; 408 } 409 410 cpufreq_frequency_table_get_attr(¢aur->freq_table[0], policy->cpu); 411 return 0; 412 } 413 414 static int eps_cpu_exit(struct cpufreq_policy *policy) 415 { 416 unsigned int cpu = policy->cpu; 417 418 /* Bye */ 419 cpufreq_frequency_table_put_attr(policy->cpu); 420 kfree(eps_cpu[cpu]); 421 eps_cpu[cpu] = NULL; 422 return 0; 423 } 424 425 static struct freq_attr *eps_attr[] = { 426 &cpufreq_freq_attr_scaling_available_freqs, 427 NULL, 428 }; 429 430 static struct cpufreq_driver eps_driver = { 431 .verify = eps_verify, 432 .target = eps_target, 433 .init = eps_cpu_init, 434 .exit = eps_cpu_exit, 435 .get = eps_get, 436 .name = "e_powersaver", 437 .owner = THIS_MODULE, 438 .attr = eps_attr, 439 }; 440 441 442 /* This driver will work only on Centaur C7 processors with 443 * Enhanced SpeedStep/PowerSaver registers */ 444 static const struct x86_cpu_id eps_cpu_id[] = { 445 { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST }, 446 {} 447 }; 448 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id); 449 450 static int __init eps_init(void) 451 { 452 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10) 453 return -ENODEV; 454 if (cpufreq_register_driver(&eps_driver)) 455 return -EINVAL; 456 return 0; 457 } 458 459 static void __exit eps_exit(void) 460 { 461 cpufreq_unregister_driver(&eps_driver); 462 } 463 464 /* Allow user to overclock his machine or to change frequency to higher after 465 * unloading module */ 466 module_param(freq_failsafe_off, int, 0644); 467 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check"); 468 module_param(voltage_failsafe_off, int, 0644); 469 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check"); 470 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 471 module_param(ignore_acpi_limit, int, 0644); 472 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit"); 473 #endif 474 module_param(set_max_voltage, int, 0644); 475 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only"); 476 477 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>"); 478 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's."); 479 MODULE_LICENSE("GPL"); 480 481 module_init(eps_init); 482 module_exit(eps_exit); 483