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 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/init.h> 19 #include <linux/cpufreq.h> 20 #include <linux/sched.h> /* current */ 21 #include <linux/delay.h> 22 #include <linux/compiler.h> 23 #include <linux/gfp.h> 24 25 #include <asm/msr.h> 26 #include <asm/processor.h> 27 #include <asm/cpufeature.h> 28 #include <asm/cpu_device_id.h> 29 30 #define PFX "speedstep-centrino: " 31 #define MAINTAINER "cpufreq@vger.kernel.org" 32 33 #define INTEL_MSR_RANGE (0xffff) 34 35 struct cpu_id 36 { 37 __u8 x86; /* CPU family */ 38 __u8 x86_model; /* model */ 39 __u8 x86_mask; /* stepping */ 40 }; 41 42 enum { 43 CPU_BANIAS, 44 CPU_DOTHAN_A1, 45 CPU_DOTHAN_A2, 46 CPU_DOTHAN_B0, 47 CPU_MP4HT_D0, 48 CPU_MP4HT_E0, 49 }; 50 51 static const struct cpu_id cpu_ids[] = { 52 [CPU_BANIAS] = { 6, 9, 5 }, 53 [CPU_DOTHAN_A1] = { 6, 13, 1 }, 54 [CPU_DOTHAN_A2] = { 6, 13, 2 }, 55 [CPU_DOTHAN_B0] = { 6, 13, 6 }, 56 [CPU_MP4HT_D0] = {15, 3, 4 }, 57 [CPU_MP4HT_E0] = {15, 4, 1 }, 58 }; 59 #define N_IDS ARRAY_SIZE(cpu_ids) 60 61 struct cpu_model 62 { 63 const struct cpu_id *cpu_id; 64 const char *model_name; 65 unsigned max_freq; /* max clock in kHz */ 66 67 struct cpufreq_frequency_table *op_points; /* clock/voltage pairs */ 68 }; 69 static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, 70 const struct cpu_id *x); 71 72 /* Operating points for current CPU */ 73 static DEFINE_PER_CPU(struct cpu_model *, centrino_model); 74 static DEFINE_PER_CPU(const struct cpu_id *, centrino_cpu); 75 76 static struct cpufreq_driver centrino_driver; 77 78 #ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE 79 80 /* Computes the correct form for IA32_PERF_CTL MSR for a particular 81 frequency/voltage operating point; frequency in MHz, volts in mV. 82 This is stored as "driver_data" in the structure. */ 83 #define OP(mhz, mv) \ 84 { \ 85 .frequency = (mhz) * 1000, \ 86 .driver_data = (((mhz)/100) << 8) | ((mv - 700) / 16) \ 87 } 88 89 /* 90 * These voltage tables were derived from the Intel Pentium M 91 * datasheet, document 25261202.pdf, Table 5. I have verified they 92 * are consistent with my IBM ThinkPad X31, which has a 1.3GHz Pentium 93 * M. 94 */ 95 96 /* Ultra Low Voltage Intel Pentium M processor 900MHz (Banias) */ 97 static struct cpufreq_frequency_table banias_900[] = 98 { 99 OP(600, 844), 100 OP(800, 988), 101 OP(900, 1004), 102 { .frequency = CPUFREQ_TABLE_END } 103 }; 104 105 /* Ultra Low Voltage Intel Pentium M processor 1000MHz (Banias) */ 106 static struct cpufreq_frequency_table banias_1000[] = 107 { 108 OP(600, 844), 109 OP(800, 972), 110 OP(900, 988), 111 OP(1000, 1004), 112 { .frequency = CPUFREQ_TABLE_END } 113 }; 114 115 /* Low Voltage Intel Pentium M processor 1.10GHz (Banias) */ 116 static struct cpufreq_frequency_table banias_1100[] = 117 { 118 OP( 600, 956), 119 OP( 800, 1020), 120 OP( 900, 1100), 121 OP(1000, 1164), 122 OP(1100, 1180), 123 { .frequency = CPUFREQ_TABLE_END } 124 }; 125 126 127 /* Low Voltage Intel Pentium M processor 1.20GHz (Banias) */ 128 static struct cpufreq_frequency_table banias_1200[] = 129 { 130 OP( 600, 956), 131 OP( 800, 1004), 132 OP( 900, 1020), 133 OP(1000, 1100), 134 OP(1100, 1164), 135 OP(1200, 1180), 136 { .frequency = CPUFREQ_TABLE_END } 137 }; 138 139 /* Intel Pentium M processor 1.30GHz (Banias) */ 140 static struct cpufreq_frequency_table banias_1300[] = 141 { 142 OP( 600, 956), 143 OP( 800, 1260), 144 OP(1000, 1292), 145 OP(1200, 1356), 146 OP(1300, 1388), 147 { .frequency = CPUFREQ_TABLE_END } 148 }; 149 150 /* Intel Pentium M processor 1.40GHz (Banias) */ 151 static struct cpufreq_frequency_table banias_1400[] = 152 { 153 OP( 600, 956), 154 OP( 800, 1180), 155 OP(1000, 1308), 156 OP(1200, 1436), 157 OP(1400, 1484), 158 { .frequency = CPUFREQ_TABLE_END } 159 }; 160 161 /* Intel Pentium M processor 1.50GHz (Banias) */ 162 static struct cpufreq_frequency_table banias_1500[] = 163 { 164 OP( 600, 956), 165 OP( 800, 1116), 166 OP(1000, 1228), 167 OP(1200, 1356), 168 OP(1400, 1452), 169 OP(1500, 1484), 170 { .frequency = CPUFREQ_TABLE_END } 171 }; 172 173 /* Intel Pentium M processor 1.60GHz (Banias) */ 174 static struct cpufreq_frequency_table banias_1600[] = 175 { 176 OP( 600, 956), 177 OP( 800, 1036), 178 OP(1000, 1164), 179 OP(1200, 1276), 180 OP(1400, 1420), 181 OP(1600, 1484), 182 { .frequency = CPUFREQ_TABLE_END } 183 }; 184 185 /* Intel Pentium M processor 1.70GHz (Banias) */ 186 static struct cpufreq_frequency_table banias_1700[] = 187 { 188 OP( 600, 956), 189 OP( 800, 1004), 190 OP(1000, 1116), 191 OP(1200, 1228), 192 OP(1400, 1308), 193 OP(1700, 1484), 194 { .frequency = CPUFREQ_TABLE_END } 195 }; 196 #undef OP 197 198 #define _BANIAS(cpuid, max, name) \ 199 { .cpu_id = cpuid, \ 200 .model_name = "Intel(R) Pentium(R) M processor " name "MHz", \ 201 .max_freq = (max)*1000, \ 202 .op_points = banias_##max, \ 203 } 204 #define BANIAS(max) _BANIAS(&cpu_ids[CPU_BANIAS], max, #max) 205 206 /* CPU models, their operating frequency range, and freq/voltage 207 operating points */ 208 static struct cpu_model models[] = 209 { 210 _BANIAS(&cpu_ids[CPU_BANIAS], 900, " 900"), 211 BANIAS(1000), 212 BANIAS(1100), 213 BANIAS(1200), 214 BANIAS(1300), 215 BANIAS(1400), 216 BANIAS(1500), 217 BANIAS(1600), 218 BANIAS(1700), 219 220 /* NULL model_name is a wildcard */ 221 { &cpu_ids[CPU_DOTHAN_A1], NULL, 0, NULL }, 222 { &cpu_ids[CPU_DOTHAN_A2], NULL, 0, NULL }, 223 { &cpu_ids[CPU_DOTHAN_B0], NULL, 0, NULL }, 224 { &cpu_ids[CPU_MP4HT_D0], NULL, 0, NULL }, 225 { &cpu_ids[CPU_MP4HT_E0], NULL, 0, NULL }, 226 227 { NULL, } 228 }; 229 #undef _BANIAS 230 #undef BANIAS 231 232 static int centrino_cpu_init_table(struct cpufreq_policy *policy) 233 { 234 struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); 235 struct cpu_model *model; 236 237 for(model = models; model->cpu_id != NULL; model++) 238 if (centrino_verify_cpu_id(cpu, model->cpu_id) && 239 (model->model_name == NULL || 240 strcmp(cpu->x86_model_id, model->model_name) == 0)) 241 break; 242 243 if (model->cpu_id == NULL) { 244 /* No match at all */ 245 pr_debug("no support for CPU model \"%s\": " 246 "send /proc/cpuinfo to " MAINTAINER "\n", 247 cpu->x86_model_id); 248 return -ENOENT; 249 } 250 251 if (model->op_points == NULL) { 252 /* Matched a non-match */ 253 pr_debug("no table support for CPU model \"%s\"\n", 254 cpu->x86_model_id); 255 pr_debug("try using the acpi-cpufreq driver\n"); 256 return -ENOENT; 257 } 258 259 per_cpu(centrino_model, policy->cpu) = model; 260 261 pr_debug("found \"%s\": max frequency: %dkHz\n", 262 model->model_name, model->max_freq); 263 264 return 0; 265 } 266 267 #else 268 static inline int centrino_cpu_init_table(struct cpufreq_policy *policy) 269 { 270 return -ENODEV; 271 } 272 #endif /* CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE */ 273 274 static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, 275 const struct cpu_id *x) 276 { 277 if ((c->x86 == x->x86) && 278 (c->x86_model == x->x86_model) && 279 (c->x86_mask == x->x86_mask)) 280 return 1; 281 return 0; 282 } 283 284 /* To be called only after centrino_model is initialized */ 285 static unsigned extract_clock(unsigned msr, unsigned int cpu, int failsafe) 286 { 287 int i; 288 289 /* 290 * Extract clock in kHz from PERF_CTL value 291 * for centrino, as some DSDTs are buggy. 292 * Ideally, this can be done using the acpi_data structure. 293 */ 294 if ((per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_BANIAS]) || 295 (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_A1]) || 296 (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_B0])) { 297 msr = (msr >> 8) & 0xff; 298 return msr * 100000; 299 } 300 301 if ((!per_cpu(centrino_model, cpu)) || 302 (!per_cpu(centrino_model, cpu)->op_points)) 303 return 0; 304 305 msr &= 0xffff; 306 for (i = 0; 307 per_cpu(centrino_model, cpu)->op_points[i].frequency 308 != CPUFREQ_TABLE_END; 309 i++) { 310 if (msr == per_cpu(centrino_model, cpu)->op_points[i].driver_data) 311 return per_cpu(centrino_model, cpu)-> 312 op_points[i].frequency; 313 } 314 if (failsafe) 315 return per_cpu(centrino_model, cpu)->op_points[i-1].frequency; 316 else 317 return 0; 318 } 319 320 /* Return the current CPU frequency in kHz */ 321 static unsigned int get_cur_freq(unsigned int cpu) 322 { 323 unsigned l, h; 324 unsigned clock_freq; 325 326 rdmsr_on_cpu(cpu, MSR_IA32_PERF_STATUS, &l, &h); 327 clock_freq = extract_clock(l, cpu, 0); 328 329 if (unlikely(clock_freq == 0)) { 330 /* 331 * On some CPUs, we can see transient MSR values (which are 332 * not present in _PSS), while CPU is doing some automatic 333 * P-state transition (like TM2). Get the last freq set 334 * in PERF_CTL. 335 */ 336 rdmsr_on_cpu(cpu, MSR_IA32_PERF_CTL, &l, &h); 337 clock_freq = extract_clock(l, cpu, 1); 338 } 339 return clock_freq; 340 } 341 342 343 static int centrino_cpu_init(struct cpufreq_policy *policy) 344 { 345 struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); 346 unsigned l, h; 347 int i; 348 349 /* Only Intel makes Enhanced Speedstep-capable CPUs */ 350 if (cpu->x86_vendor != X86_VENDOR_INTEL || 351 !cpu_has(cpu, X86_FEATURE_EST)) 352 return -ENODEV; 353 354 if (cpu_has(cpu, X86_FEATURE_CONSTANT_TSC)) 355 centrino_driver.flags |= CPUFREQ_CONST_LOOPS; 356 357 if (policy->cpu != 0) 358 return -ENODEV; 359 360 for (i = 0; i < N_IDS; i++) 361 if (centrino_verify_cpu_id(cpu, &cpu_ids[i])) 362 break; 363 364 if (i != N_IDS) 365 per_cpu(centrino_cpu, policy->cpu) = &cpu_ids[i]; 366 367 if (!per_cpu(centrino_cpu, policy->cpu)) { 368 pr_debug("found unsupported CPU with " 369 "Enhanced SpeedStep: send /proc/cpuinfo to " 370 MAINTAINER "\n"); 371 return -ENODEV; 372 } 373 374 if (centrino_cpu_init_table(policy)) 375 return -ENODEV; 376 377 /* Check to see if Enhanced SpeedStep is enabled, and try to 378 enable it if not. */ 379 rdmsr(MSR_IA32_MISC_ENABLE, l, h); 380 381 if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 382 l |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; 383 pr_debug("trying to enable Enhanced SpeedStep (%x)\n", l); 384 wrmsr(MSR_IA32_MISC_ENABLE, l, h); 385 386 /* check to see if it stuck */ 387 rdmsr(MSR_IA32_MISC_ENABLE, l, h); 388 if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { 389 printk(KERN_INFO PFX 390 "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 cpufreq_frequency_table_put_attr(cpu); 410 411 per_cpu(centrino_model, cpu) = NULL; 412 413 return 0; 414 } 415 416 /** 417 * centrino_setpolicy - set a new CPUFreq policy 418 * @policy: new policy 419 * @index: index of target frequency 420 * 421 * Sets a new CPUFreq policy. 422 */ 423 static int centrino_target(struct cpufreq_policy *policy, unsigned int index) 424 { 425 unsigned int msr, oldmsr = 0, h = 0, cpu = policy->cpu; 426 int retval = 0; 427 unsigned int j, first_cpu; 428 struct cpufreq_frequency_table *op_points; 429 cpumask_var_t covered_cpus; 430 431 if (unlikely(!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))) 432 return -ENOMEM; 433 434 if (unlikely(per_cpu(centrino_model, cpu) == NULL)) { 435 retval = -ENODEV; 436 goto out; 437 } 438 439 first_cpu = 1; 440 op_points = &per_cpu(centrino_model, cpu)->op_points[index]; 441 for_each_cpu(j, policy->cpus) { 442 int good_cpu; 443 444 /* 445 * Support for SMP systems. 446 * Make sure we are running on CPU that wants to change freq 447 */ 448 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) 449 good_cpu = cpumask_any_and(policy->cpus, 450 cpu_online_mask); 451 else 452 good_cpu = j; 453 454 if (good_cpu >= nr_cpu_ids) { 455 pr_debug("couldn't limit to CPUs in this domain\n"); 456 retval = -EAGAIN; 457 if (first_cpu) { 458 /* We haven't started the transition yet. */ 459 goto out; 460 } 461 break; 462 } 463 464 msr = op_points->driver_data; 465 466 if (first_cpu) { 467 rdmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, &oldmsr, &h); 468 if (msr == (oldmsr & 0xffff)) { 469 pr_debug("no change needed - msr was and needs " 470 "to be %x\n", oldmsr); 471 retval = 0; 472 goto out; 473 } 474 475 first_cpu = 0; 476 /* all but 16 LSB are reserved, treat them with care */ 477 oldmsr &= ~0xffff; 478 msr &= 0xffff; 479 oldmsr |= msr; 480 } 481 482 wrmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, oldmsr, h); 483 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) 484 break; 485 486 cpumask_set_cpu(j, covered_cpus); 487 } 488 489 if (unlikely(retval)) { 490 /* 491 * We have failed halfway through the frequency change. 492 * We have sent callbacks to policy->cpus and 493 * MSRs have already been written on coverd_cpus. 494 * Best effort undo.. 495 */ 496 497 for_each_cpu(j, covered_cpus) 498 wrmsr_on_cpu(j, MSR_IA32_PERF_CTL, oldmsr, h); 499 } 500 retval = 0; 501 502 out: 503 free_cpumask_var(covered_cpus); 504 return retval; 505 } 506 507 static struct cpufreq_driver centrino_driver = { 508 .name = "centrino", /* should be speedstep-centrino, 509 but there's a 16 char limit */ 510 .init = centrino_cpu_init, 511 .exit = centrino_cpu_exit, 512 .verify = cpufreq_generic_frequency_table_verify, 513 .target_index = centrino_target, 514 .get = get_cur_freq, 515 .attr = cpufreq_generic_attr, 516 }; 517 518 /* 519 * This doesn't replace the detailed checks above because 520 * the generic CPU IDs don't have a way to match for steppings 521 * or ASCII model IDs. 522 */ 523 static const struct x86_cpu_id centrino_ids[] = { 524 { X86_VENDOR_INTEL, 6, 9, X86_FEATURE_EST }, 525 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 526 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 527 { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, 528 { X86_VENDOR_INTEL, 15, 3, X86_FEATURE_EST }, 529 { X86_VENDOR_INTEL, 15, 4, X86_FEATURE_EST }, 530 {} 531 }; 532 #if 0 533 /* Autoload or not? Do not for now. */ 534 MODULE_DEVICE_TABLE(x86cpu, centrino_ids); 535 #endif 536 537 /** 538 * centrino_init - initializes the Enhanced SpeedStep CPUFreq driver 539 * 540 * Initializes the Enhanced SpeedStep support. Returns -ENODEV on 541 * unsupported devices, -ENOENT if there's no voltage table for this 542 * particular CPU model, -EINVAL on problems during initiatization, 543 * and zero on success. 544 * 545 * This is quite picky. Not only does the CPU have to advertise the 546 * "est" flag in the cpuid capability flags, we look for a specific 547 * CPU model and stepping, and we need to have the exact model name in 548 * our voltage tables. That is, be paranoid about not releasing 549 * someone's valuable magic smoke. 550 */ 551 static int __init centrino_init(void) 552 { 553 if (!x86_match_cpu(centrino_ids)) 554 return -ENODEV; 555 return cpufreq_register_driver(¢rino_driver); 556 } 557 558 static void __exit centrino_exit(void) 559 { 560 cpufreq_unregister_driver(¢rino_driver); 561 } 562 563 MODULE_AUTHOR ("Jeremy Fitzhardinge <jeremy@goop.org>"); 564 MODULE_DESCRIPTION ("Enhanced SpeedStep driver for Intel Pentium M processors."); 565 MODULE_LICENSE ("GPL"); 566 567 late_initcall(centrino_init); 568 module_exit(centrino_exit); 569