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 struct cpufreq_policy *policy, 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(policy->cpu); 116 freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff); 117 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); 118 119 /* Wait while CPU is busy */ 120 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 121 i = 0; 122 while (lo & ((1 << 16) | (1 << 17))) { 123 udelay(16); 124 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 125 i++; 126 if (unlikely(i > 64)) { 127 err = -ENODEV; 128 goto postchange; 129 } 130 } 131 /* Set new multiplier and voltage */ 132 wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0); 133 /* Wait until transition end */ 134 i = 0; 135 do { 136 udelay(16); 137 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 138 i++; 139 if (unlikely(i > 64)) { 140 err = -ENODEV; 141 goto postchange; 142 } 143 } while (lo & ((1 << 16) | (1 << 17))); 144 145 /* Return current frequency */ 146 postchange: 147 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 148 freqs.new = centaur->fsb * ((lo >> 8) & 0xff); 149 150 #ifdef DEBUG 151 { 152 u8 current_multiplier, current_voltage; 153 154 /* 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", 161 current_multiplier); 162 } 163 #endif 164 if (err) 165 freqs.new = freqs.old; 166 167 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); 168 return err; 169 } 170 171 static int eps_target(struct cpufreq_policy *policy, 172 unsigned int target_freq, 173 unsigned int relation) 174 { 175 struct eps_cpu_data *centaur; 176 unsigned int newstate = 0; 177 unsigned int cpu = policy->cpu; 178 unsigned int dest_state; 179 int ret; 180 181 if (unlikely(eps_cpu[cpu] == NULL)) 182 return -ENODEV; 183 centaur = eps_cpu[cpu]; 184 185 if (unlikely(cpufreq_frequency_table_target(policy, 186 &eps_cpu[cpu]->freq_table[0], 187 target_freq, 188 relation, 189 &newstate))) { 190 return -EINVAL; 191 } 192 193 /* Make frequency transition */ 194 dest_state = centaur->freq_table[newstate].driver_data & 0xffff; 195 ret = eps_set_state(centaur, policy, dest_state); 196 if (ret) 197 printk(KERN_ERR "eps: Timeout!\n"); 198 return ret; 199 } 200 201 static int eps_verify(struct cpufreq_policy *policy) 202 { 203 return cpufreq_frequency_table_verify(policy, 204 &eps_cpu[policy->cpu]->freq_table[0]); 205 } 206 207 static int eps_cpu_init(struct cpufreq_policy *policy) 208 { 209 unsigned int i; 210 u32 lo, hi; 211 u64 val; 212 u8 current_multiplier, current_voltage; 213 u8 max_multiplier, max_voltage; 214 u8 min_multiplier, min_voltage; 215 u8 brand = 0; 216 u32 fsb; 217 struct eps_cpu_data *centaur; 218 struct cpuinfo_x86 *c = &cpu_data(0); 219 struct cpufreq_frequency_table *f_table; 220 int k, step, voltage; 221 int ret; 222 int states; 223 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 224 unsigned int limit; 225 #endif 226 227 if (policy->cpu != 0) 228 return -ENODEV; 229 230 /* Check brand */ 231 printk(KERN_INFO "eps: Detected VIA "); 232 233 switch (c->x86_model) { 234 case 10: 235 rdmsr(0x1153, lo, hi); 236 brand = (((lo >> 2) ^ lo) >> 18) & 3; 237 printk(KERN_CONT "Model A "); 238 break; 239 case 13: 240 rdmsr(0x1154, lo, hi); 241 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff; 242 printk(KERN_CONT "Model D "); 243 break; 244 } 245 246 switch (brand) { 247 case EPS_BRAND_C7M: 248 printk(KERN_CONT "C7-M\n"); 249 break; 250 case EPS_BRAND_C7: 251 printk(KERN_CONT "C7\n"); 252 break; 253 case EPS_BRAND_EDEN: 254 printk(KERN_CONT "Eden\n"); 255 break; 256 case EPS_BRAND_C7D: 257 printk(KERN_CONT "C7-D\n"); 258 break; 259 case EPS_BRAND_C3: 260 printk(KERN_CONT "C3\n"); 261 return -ENODEV; 262 break; 263 } 264 /* Enable Enhanced PowerSaver */ 265 rdmsrl(MSR_IA32_MISC_ENABLE, val); 266 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 267 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; 268 wrmsrl(MSR_IA32_MISC_ENABLE, val); 269 /* Can be locked at 0 */ 270 rdmsrl(MSR_IA32_MISC_ENABLE, val); 271 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 272 printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n"); 273 return -ENODEV; 274 } 275 } 276 277 /* Print voltage and multiplier */ 278 rdmsr(MSR_IA32_PERF_STATUS, lo, hi); 279 current_voltage = lo & 0xff; 280 printk(KERN_INFO "eps: Current voltage = %dmV\n", 281 current_voltage * 16 + 700); 282 current_multiplier = (lo >> 8) & 0xff; 283 printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier); 284 285 /* Print limits */ 286 max_voltage = hi & 0xff; 287 printk(KERN_INFO "eps: Highest voltage = %dmV\n", 288 max_voltage * 16 + 700); 289 max_multiplier = (hi >> 8) & 0xff; 290 printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier); 291 min_voltage = (hi >> 16) & 0xff; 292 printk(KERN_INFO "eps: Lowest voltage = %dmV\n", 293 min_voltage * 16 + 700); 294 min_multiplier = (hi >> 24) & 0xff; 295 printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier); 296 297 /* Sanity checks */ 298 if (current_multiplier == 0 || max_multiplier == 0 299 || min_multiplier == 0) 300 return -EINVAL; 301 if (current_multiplier > max_multiplier 302 || max_multiplier <= min_multiplier) 303 return -EINVAL; 304 if (current_voltage > 0x1f || max_voltage > 0x1f) 305 return -EINVAL; 306 if (max_voltage < min_voltage 307 || current_voltage < min_voltage 308 || current_voltage > max_voltage) 309 return -EINVAL; 310 311 /* Check for systems using underclocked CPU */ 312 if (!freq_failsafe_off && max_multiplier != current_multiplier) { 313 printk(KERN_INFO "eps: Your processor is running at different " 314 "frequency then its maximum. Aborting.\n"); 315 printk(KERN_INFO "eps: You can use freq_failsafe_off option " 316 "to disable this check.\n"); 317 return -EINVAL; 318 } 319 if (!voltage_failsafe_off && max_voltage != current_voltage) { 320 printk(KERN_INFO "eps: Your processor is running at different " 321 "voltage then its maximum. Aborting.\n"); 322 printk(KERN_INFO "eps: You can use voltage_failsafe_off " 323 "option to disable this check.\n"); 324 return -EINVAL; 325 } 326 327 /* Calc FSB speed */ 328 fsb = cpu_khz / current_multiplier; 329 330 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 331 /* Check for ACPI processor speed limit */ 332 if (!ignore_acpi_limit && !eps_acpi_init()) { 333 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) { 334 printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n", 335 limit/1000000, 336 (limit%1000000)/10000); 337 eps_acpi_exit(policy); 338 /* Check if max_multiplier is in BIOS limits */ 339 if (limit && max_multiplier * fsb > limit) { 340 printk(KERN_INFO "eps: Aborting.\n"); 341 return -EINVAL; 342 } 343 } 344 } 345 #endif 346 347 /* Allow user to set lower maximum voltage then that reported 348 * by processor */ 349 if (brand == EPS_BRAND_C7M && set_max_voltage) { 350 u32 v; 351 352 /* Change mV to something hardware can use */ 353 v = (set_max_voltage - 700) / 16; 354 /* Check if voltage is within limits */ 355 if (v >= min_voltage && v <= max_voltage) { 356 printk(KERN_INFO "eps: Setting %dmV as maximum.\n", 357 v * 16 + 700); 358 max_voltage = v; 359 } 360 } 361 362 /* Calc number of p-states supported */ 363 if (brand == EPS_BRAND_C7M) 364 states = max_multiplier - min_multiplier + 1; 365 else 366 states = 2; 367 368 /* Allocate private data and frequency table for current cpu */ 369 centaur = kzalloc(sizeof(struct eps_cpu_data) 370 + (states + 1) * sizeof(struct cpufreq_frequency_table), 371 GFP_KERNEL); 372 if (!centaur) 373 return -ENOMEM; 374 eps_cpu[0] = centaur; 375 376 /* Copy basic values */ 377 centaur->fsb = fsb; 378 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 379 centaur->bios_limit = limit; 380 #endif 381 382 /* Fill frequency and MSR value table */ 383 f_table = ¢aur->freq_table[0]; 384 if (brand != EPS_BRAND_C7M) { 385 f_table[0].frequency = fsb * min_multiplier; 386 f_table[0].driver_data = (min_multiplier << 8) | min_voltage; 387 f_table[1].frequency = fsb * max_multiplier; 388 f_table[1].driver_data = (max_multiplier << 8) | max_voltage; 389 f_table[2].frequency = CPUFREQ_TABLE_END; 390 } else { 391 k = 0; 392 step = ((max_voltage - min_voltage) * 256) 393 / (max_multiplier - min_multiplier); 394 for (i = min_multiplier; i <= max_multiplier; i++) { 395 voltage = (k * step) / 256 + min_voltage; 396 f_table[k].frequency = fsb * i; 397 f_table[k].driver_data = (i << 8) | voltage; 398 k++; 399 } 400 f_table[k].frequency = CPUFREQ_TABLE_END; 401 } 402 403 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */ 404 policy->cur = fsb * current_multiplier; 405 406 ret = cpufreq_frequency_table_cpuinfo(policy, ¢aur->freq_table[0]); 407 if (ret) { 408 kfree(centaur); 409 return ret; 410 } 411 412 cpufreq_frequency_table_get_attr(¢aur->freq_table[0], policy->cpu); 413 return 0; 414 } 415 416 static int eps_cpu_exit(struct cpufreq_policy *policy) 417 { 418 unsigned int cpu = policy->cpu; 419 420 /* Bye */ 421 cpufreq_frequency_table_put_attr(policy->cpu); 422 kfree(eps_cpu[cpu]); 423 eps_cpu[cpu] = NULL; 424 return 0; 425 } 426 427 static struct freq_attr *eps_attr[] = { 428 &cpufreq_freq_attr_scaling_available_freqs, 429 NULL, 430 }; 431 432 static struct cpufreq_driver eps_driver = { 433 .verify = eps_verify, 434 .target = eps_target, 435 .init = eps_cpu_init, 436 .exit = eps_cpu_exit, 437 .get = eps_get, 438 .name = "e_powersaver", 439 .owner = THIS_MODULE, 440 .attr = eps_attr, 441 }; 442 443 444 /* This driver will work only on Centaur C7 processors with 445 * Enhanced SpeedStep/PowerSaver registers */ 446 static const struct x86_cpu_id eps_cpu_id[] = { 447 { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST }, 448 {} 449 }; 450 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id); 451 452 static int __init eps_init(void) 453 { 454 if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10) 455 return -ENODEV; 456 if (cpufreq_register_driver(&eps_driver)) 457 return -EINVAL; 458 return 0; 459 } 460 461 static void __exit eps_exit(void) 462 { 463 cpufreq_unregister_driver(&eps_driver); 464 } 465 466 /* Allow user to overclock his machine or to change frequency to higher after 467 * unloading module */ 468 module_param(freq_failsafe_off, int, 0644); 469 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check"); 470 module_param(voltage_failsafe_off, int, 0644); 471 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check"); 472 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE 473 module_param(ignore_acpi_limit, int, 0644); 474 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit"); 475 #endif 476 module_param(set_max_voltage, int, 0644); 477 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only"); 478 479 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>"); 480 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's."); 481 MODULE_LICENSE("GPL"); 482 483 module_init(eps_init); 484 module_exit(eps_exit); 485