1 /* 2 * cpufreq driver for Enhanced SpeedStep, as found in Intel's Pentium 3 * M (part of the Centrino chipset). 4 * 5 * Since the original Pentium M, most new Intel CPUs support Enhanced 6 * SpeedStep. 7 * 8 * Despite the "SpeedStep" in the name, this is almost entirely unlike 9 * traditional SpeedStep. 10 * 11 * Modelled on speedstep.c 12 * 13 * Copyright (C) 2003 Jeremy Fitzhardinge <jeremy@goop.org> 14 */ 15 16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/cpufreq.h> 22 #include <linux/sched.h> /* current */ 23 #include <linux/delay.h> 24 #include <linux/compiler.h> 25 #include <linux/gfp.h> 26 27 #include <asm/msr.h> 28 #include <asm/processor.h> 29 #include <asm/cpufeature.h> 30 #include <asm/cpu_device_id.h> 31 32 #define MAINTAINER "linux-pm@vger.kernel.org" 33 34 #define INTEL_MSR_RANGE (0xffff) 35 36 struct cpu_id 37 { 38 __u8 x86; /* CPU family */ 39 __u8 x86_model; /* model */ 40 __u8 x86_stepping; /* stepping */ 41 }; 42 43 enum { 44 CPU_BANIAS, 45 CPU_DOTHAN_A1, 46 CPU_DOTHAN_A2, 47 CPU_DOTHAN_B0, 48 CPU_MP4HT_D0, 49 CPU_MP4HT_E0, 50 }; 51 52 static const struct cpu_id cpu_ids[] = { 53 [CPU_BANIAS] = { 6, 9, 5 }, 54 [CPU_DOTHAN_A1] = { 6, 13, 1 }, 55 [CPU_DOTHAN_A2] = { 6, 13, 2 }, 56 [CPU_DOTHAN_B0] = { 6, 13, 6 }, 57 [CPU_MP4HT_D0] = {15, 3, 4 }, 58 [CPU_MP4HT_E0] = {15, 4, 1 }, 59 }; 60 #define N_IDS ARRAY_SIZE(cpu_ids) 61 62 struct cpu_model 63 { 64 const struct cpu_id *cpu_id; 65 const char *model_name; 66 unsigned max_freq; /* max clock in kHz */ 67 68 struct cpufreq_frequency_table *op_points; /* clock/voltage pairs */ 69 }; 70 static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, 71 const struct cpu_id *x); 72 73 /* Operating points for current CPU */ 74 static DEFINE_PER_CPU(struct cpu_model *, centrino_model); 75 static DEFINE_PER_CPU(const struct cpu_id *, centrino_cpu); 76 77 static struct cpufreq_driver centrino_driver; 78 79 #ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE 80 81 /* Computes the correct form for IA32_PERF_CTL MSR for a particular 82 frequency/voltage operating point; frequency in MHz, volts in mV. 83 This is stored as "driver_data" in the structure. */ 84 #define OP(mhz, mv) \ 85 { \ 86 .frequency = (mhz) * 1000, \ 87 .driver_data = (((mhz)/100) << 8) | ((mv - 700) / 16) \ 88 } 89 90 /* 91 * These voltage tables were derived from the Intel Pentium M 92 * datasheet, document 25261202.pdf, Table 5. I have verified they 93 * are consistent with my IBM ThinkPad X31, which has a 1.3GHz Pentium 94 * M. 95 */ 96 97 /* Ultra Low Voltage Intel Pentium M processor 900MHz (Banias) */ 98 static struct cpufreq_frequency_table banias_900[] = 99 { 100 OP(600, 844), 101 OP(800, 988), 102 OP(900, 1004), 103 { .frequency = CPUFREQ_TABLE_END } 104 }; 105 106 /* Ultra Low Voltage Intel Pentium M processor 1000MHz (Banias) */ 107 static struct cpufreq_frequency_table banias_1000[] = 108 { 109 OP(600, 844), 110 OP(800, 972), 111 OP(900, 988), 112 OP(1000, 1004), 113 { .frequency = CPUFREQ_TABLE_END } 114 }; 115 116 /* Low Voltage Intel Pentium M processor 1.10GHz (Banias) */ 117 static struct cpufreq_frequency_table banias_1100[] = 118 { 119 OP( 600, 956), 120 OP( 800, 1020), 121 OP( 900, 1100), 122 OP(1000, 1164), 123 OP(1100, 1180), 124 { .frequency = CPUFREQ_TABLE_END } 125 }; 126 127 128 /* Low Voltage Intel Pentium M processor 1.20GHz (Banias) */ 129 static struct cpufreq_frequency_table banias_1200[] = 130 { 131 OP( 600, 956), 132 OP( 800, 1004), 133 OP( 900, 1020), 134 OP(1000, 1100), 135 OP(1100, 1164), 136 OP(1200, 1180), 137 { .frequency = CPUFREQ_TABLE_END } 138 }; 139 140 /* Intel Pentium M processor 1.30GHz (Banias) */ 141 static struct cpufreq_frequency_table banias_1300[] = 142 { 143 OP( 600, 956), 144 OP( 800, 1260), 145 OP(1000, 1292), 146 OP(1200, 1356), 147 OP(1300, 1388), 148 { .frequency = CPUFREQ_TABLE_END } 149 }; 150 151 /* Intel Pentium M processor 1.40GHz (Banias) */ 152 static struct cpufreq_frequency_table banias_1400[] = 153 { 154 OP( 600, 956), 155 OP( 800, 1180), 156 OP(1000, 1308), 157 OP(1200, 1436), 158 OP(1400, 1484), 159 { .frequency = CPUFREQ_TABLE_END } 160 }; 161 162 /* Intel Pentium M processor 1.50GHz (Banias) */ 163 static struct cpufreq_frequency_table banias_1500[] = 164 { 165 OP( 600, 956), 166 OP( 800, 1116), 167 OP(1000, 1228), 168 OP(1200, 1356), 169 OP(1400, 1452), 170 OP(1500, 1484), 171 { .frequency = CPUFREQ_TABLE_END } 172 }; 173 174 /* Intel Pentium M processor 1.60GHz (Banias) */ 175 static struct cpufreq_frequency_table banias_1600[] = 176 { 177 OP( 600, 956), 178 OP( 800, 1036), 179 OP(1000, 1164), 180 OP(1200, 1276), 181 OP(1400, 1420), 182 OP(1600, 1484), 183 { .frequency = CPUFREQ_TABLE_END } 184 }; 185 186 /* Intel Pentium M processor 1.70GHz (Banias) */ 187 static struct cpufreq_frequency_table banias_1700[] = 188 { 189 OP( 600, 956), 190 OP( 800, 1004), 191 OP(1000, 1116), 192 OP(1200, 1228), 193 OP(1400, 1308), 194 OP(1700, 1484), 195 { .frequency = CPUFREQ_TABLE_END } 196 }; 197 #undef OP 198 199 #define _BANIAS(cpuid, max, name) \ 200 { .cpu_id = cpuid, \ 201 .model_name = "Intel(R) Pentium(R) M processor " name "MHz", \ 202 .max_freq = (max)*1000, \ 203 .op_points = banias_##max, \ 204 } 205 #define BANIAS(max) _BANIAS(&cpu_ids[CPU_BANIAS], max, #max) 206 207 /* CPU models, their operating frequency range, and freq/voltage 208 operating points */ 209 static struct cpu_model models[] = 210 { 211 _BANIAS(&cpu_ids[CPU_BANIAS], 900, " 900"), 212 BANIAS(1000), 213 BANIAS(1100), 214 BANIAS(1200), 215 BANIAS(1300), 216 BANIAS(1400), 217 BANIAS(1500), 218 BANIAS(1600), 219 BANIAS(1700), 220 221 /* NULL model_name is a wildcard */ 222 { &cpu_ids[CPU_DOTHAN_A1], NULL, 0, NULL }, 223 { &cpu_ids[CPU_DOTHAN_A2], NULL, 0, NULL }, 224 { &cpu_ids[CPU_DOTHAN_B0], NULL, 0, NULL }, 225 { &cpu_ids[CPU_MP4HT_D0], NULL, 0, NULL }, 226 { &cpu_ids[CPU_MP4HT_E0], NULL, 0, NULL }, 227 228 { NULL, } 229 }; 230 #undef _BANIAS 231 #undef BANIAS 232 233 static int centrino_cpu_init_table(struct cpufreq_policy *policy) 234 { 235 struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); 236 struct cpu_model *model; 237 238 for(model = models; model->cpu_id != NULL; model++) 239 if (centrino_verify_cpu_id(cpu, model->cpu_id) && 240 (model->model_name == NULL || 241 strcmp(cpu->x86_model_id, model->model_name) == 0)) 242 break; 243 244 if (model->cpu_id == NULL) { 245 /* No match at all */ 246 pr_debug("no support for CPU model \"%s\": " 247 "send /proc/cpuinfo to " MAINTAINER "\n", 248 cpu->x86_model_id); 249 return -ENOENT; 250 } 251 252 if (model->op_points == NULL) { 253 /* Matched a non-match */ 254 pr_debug("no table support for CPU model \"%s\"\n", 255 cpu->x86_model_id); 256 pr_debug("try using the acpi-cpufreq driver\n"); 257 return -ENOENT; 258 } 259 260 per_cpu(centrino_model, policy->cpu) = model; 261 262 pr_debug("found \"%s\": max frequency: %dkHz\n", 263 model->model_name, model->max_freq); 264 265 return 0; 266 } 267 268 #else 269 static inline int centrino_cpu_init_table(struct cpufreq_policy *policy) 270 { 271 return -ENODEV; 272 } 273 #endif /* CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE */ 274 275 static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, 276 const struct cpu_id *x) 277 { 278 if ((c->x86 == x->x86) && 279 (c->x86_model == x->x86_model) && 280 (c->x86_stepping == x->x86_stepping)) 281 return 1; 282 return 0; 283 } 284 285 /* To be called only after centrino_model is initialized */ 286 static unsigned extract_clock(unsigned msr, unsigned int cpu, int failsafe) 287 { 288 int i; 289 290 /* 291 * Extract clock in kHz from PERF_CTL value 292 * for centrino, as some DSDTs are buggy. 293 * Ideally, this can be done using the acpi_data structure. 294 */ 295 if ((per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_BANIAS]) || 296 (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_A1]) || 297 (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_B0])) { 298 msr = (msr >> 8) & 0xff; 299 return msr * 100000; 300 } 301 302 if ((!per_cpu(centrino_model, cpu)) || 303 (!per_cpu(centrino_model, cpu)->op_points)) 304 return 0; 305 306 msr &= 0xffff; 307 for (i = 0; 308 per_cpu(centrino_model, cpu)->op_points[i].frequency 309 != CPUFREQ_TABLE_END; 310 i++) { 311 if (msr == per_cpu(centrino_model, cpu)->op_points[i].driver_data) 312 return per_cpu(centrino_model, cpu)-> 313 op_points[i].frequency; 314 } 315 if (failsafe) 316 return per_cpu(centrino_model, cpu)->op_points[i-1].frequency; 317 else 318 return 0; 319 } 320 321 /* Return the current CPU frequency in kHz */ 322 static unsigned int get_cur_freq(unsigned int cpu) 323 { 324 unsigned l, h; 325 unsigned clock_freq; 326 327 rdmsr_on_cpu(cpu, MSR_IA32_PERF_STATUS, &l, &h); 328 clock_freq = extract_clock(l, cpu, 0); 329 330 if (unlikely(clock_freq == 0)) { 331 /* 332 * On some CPUs, we can see transient MSR values (which are 333 * not present in _PSS), while CPU is doing some automatic 334 * P-state transition (like TM2). Get the last freq set 335 * in PERF_CTL. 336 */ 337 rdmsr_on_cpu(cpu, MSR_IA32_PERF_CTL, &l, &h); 338 clock_freq = extract_clock(l, cpu, 1); 339 } 340 return clock_freq; 341 } 342 343 344 static int centrino_cpu_init(struct cpufreq_policy *policy) 345 { 346 struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); 347 unsigned l, h; 348 int i; 349 350 /* Only Intel makes Enhanced Speedstep-capable CPUs */ 351 if (cpu->x86_vendor != X86_VENDOR_INTEL || 352 !cpu_has(cpu, X86_FEATURE_EST)) 353 return -ENODEV; 354 355 if (cpu_has(cpu, X86_FEATURE_CONSTANT_TSC)) 356 centrino_driver.flags |= CPUFREQ_CONST_LOOPS; 357 358 if (policy->cpu != 0) 359 return -ENODEV; 360 361 for (i = 0; i < N_IDS; i++) 362 if (centrino_verify_cpu_id(cpu, &cpu_ids[i])) 363 break; 364 365 if (i != N_IDS) 366 per_cpu(centrino_cpu, policy->cpu) = &cpu_ids[i]; 367 368 if (!per_cpu(centrino_cpu, policy->cpu)) { 369 pr_debug("found unsupported CPU with " 370 "Enhanced SpeedStep: send /proc/cpuinfo to " 371 MAINTAINER "\n"); 372 return -ENODEV; 373 } 374 375 if (centrino_cpu_init_table(policy)) 376 return -ENODEV; 377 378 /* Check to see if Enhanced SpeedStep is enabled, and try to 379 enable it if not. */ 380 rdmsr(MSR_IA32_MISC_ENABLE, l, h); 381 382 if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 383 l |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; 384 pr_debug("trying to enable Enhanced SpeedStep (%x)\n", l); 385 wrmsr(MSR_IA32_MISC_ENABLE, l, h); 386 387 /* check to see if it stuck */ 388 rdmsr(MSR_IA32_MISC_ENABLE, l, h); 389 if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 390 pr_info("couldn't enable Enhanced SpeedStep\n"); 391 return -ENODEV; 392 } 393 } 394 395 policy->cpuinfo.transition_latency = 10000; 396 /* 10uS transition latency */ 397 398 return cpufreq_table_validate_and_show(policy, 399 per_cpu(centrino_model, policy->cpu)->op_points); 400 } 401 402 static int centrino_cpu_exit(struct cpufreq_policy *policy) 403 { 404 unsigned int cpu = policy->cpu; 405 406 if (!per_cpu(centrino_model, cpu)) 407 return -ENODEV; 408 409 per_cpu(centrino_model, cpu) = NULL; 410 411 return 0; 412 } 413 414 /** 415 * centrino_setpolicy - set a new CPUFreq policy 416 * @policy: new policy 417 * @index: index of target frequency 418 * 419 * Sets a new CPUFreq policy. 420 */ 421 static int centrino_target(struct cpufreq_policy *policy, unsigned int index) 422 { 423 unsigned int msr, oldmsr = 0, h = 0, cpu = policy->cpu; 424 int retval = 0; 425 unsigned int j, first_cpu; 426 struct cpufreq_frequency_table *op_points; 427 cpumask_var_t covered_cpus; 428 429 if (unlikely(!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))) 430 return -ENOMEM; 431 432 if (unlikely(per_cpu(centrino_model, cpu) == NULL)) { 433 retval = -ENODEV; 434 goto out; 435 } 436 437 first_cpu = 1; 438 op_points = &per_cpu(centrino_model, cpu)->op_points[index]; 439 for_each_cpu(j, policy->cpus) { 440 int good_cpu; 441 442 /* 443 * Support for SMP systems. 444 * Make sure we are running on CPU that wants to change freq 445 */ 446 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) 447 good_cpu = cpumask_any_and(policy->cpus, 448 cpu_online_mask); 449 else 450 good_cpu = j; 451 452 if (good_cpu >= nr_cpu_ids) { 453 pr_debug("couldn't limit to CPUs in this domain\n"); 454 retval = -EAGAIN; 455 if (first_cpu) { 456 /* We haven't started the transition yet. */ 457 goto out; 458 } 459 break; 460 } 461 462 msr = op_points->driver_data; 463 464 if (first_cpu) { 465 rdmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, &oldmsr, &h); 466 if (msr == (oldmsr & 0xffff)) { 467 pr_debug("no change needed - msr was and needs " 468 "to be %x\n", oldmsr); 469 retval = 0; 470 goto out; 471 } 472 473 first_cpu = 0; 474 /* all but 16 LSB are reserved, treat them with care */ 475 oldmsr &= ~0xffff; 476 msr &= 0xffff; 477 oldmsr |= msr; 478 } 479 480 wrmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, oldmsr, h); 481 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) 482 break; 483 484 cpumask_set_cpu(j, covered_cpus); 485 } 486 487 if (unlikely(retval)) { 488 /* 489 * We have failed halfway through the frequency change. 490 * We have sent callbacks to policy->cpus and 491 * MSRs have already been written on coverd_cpus. 492 * Best effort undo.. 493 */ 494 495 for_each_cpu(j, covered_cpus) 496 wrmsr_on_cpu(j, MSR_IA32_PERF_CTL, oldmsr, h); 497 } 498 retval = 0; 499 500 out: 501 free_cpumask_var(covered_cpus); 502 return retval; 503 } 504 505 static struct cpufreq_driver centrino_driver = { 506 .name = "centrino", /* should be speedstep-centrino, 507 but there's a 16 char limit */ 508 .init = centrino_cpu_init, 509 .exit = centrino_cpu_exit, 510 .verify = cpufreq_generic_frequency_table_verify, 511 .target_index = centrino_target, 512 .get = get_cur_freq, 513 .attr = cpufreq_generic_attr, 514 }; 515 516 /* 517 * This doesn't replace the detailed checks above because 518 * the generic CPU IDs don't have a way to match for steppings 519 * or ASCII model IDs. 520 */ 521 static const struct x86_cpu_id centrino_ids[] = { 522 { X86_VENDOR_INTEL, 6, 9, X86_FEATURE_EST }, 523 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 524 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 525 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 526 { X86_VENDOR_INTEL, 15, 3, X86_FEATURE_EST }, 527 { X86_VENDOR_INTEL, 15, 4, X86_FEATURE_EST }, 528 {} 529 }; 530 #if 0 531 /* Autoload or not? Do not for now. */ 532 MODULE_DEVICE_TABLE(x86cpu, centrino_ids); 533 #endif 534 535 /** 536 * centrino_init - initializes the Enhanced SpeedStep CPUFreq driver 537 * 538 * Initializes the Enhanced SpeedStep support. Returns -ENODEV on 539 * unsupported devices, -ENOENT if there's no voltage table for this 540 * particular CPU model, -EINVAL on problems during initiatization, 541 * and zero on success. 542 * 543 * This is quite picky. Not only does the CPU have to advertise the 544 * "est" flag in the cpuid capability flags, we look for a specific 545 * CPU model and stepping, and we need to have the exact model name in 546 * our voltage tables. That is, be paranoid about not releasing 547 * someone's valuable magic smoke. 548 */ 549 static int __init centrino_init(void) 550 { 551 if (!x86_match_cpu(centrino_ids)) 552 return -ENODEV; 553 return cpufreq_register_driver(¢rino_driver); 554 } 555 556 static void __exit centrino_exit(void) 557 { 558 cpufreq_unregister_driver(¢rino_driver); 559 } 560 561 MODULE_AUTHOR ("Jeremy Fitzhardinge <jeremy@goop.org>"); 562 MODULE_DESCRIPTION ("Enhanced SpeedStep driver for Intel Pentium M processors."); 563 MODULE_LICENSE ("GPL"); 564 565 late_initcall(centrino_init); 566 module_exit(centrino_exit); 567