drivers/acpi/processor_throttling.c

   1 /*
   2  * processor_throttling.c - Throttling submodule of the ACPI processor driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *
  10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or (at
  15  *  your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful, but
  18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  *  General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License along
  23  *  with this program; if not, write to the Free Software Foundation, Inc.,
  24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  25  *
  26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  27  */
  28
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/cpufreq.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/seq_file.h>
  35
  36 #include <asm/io.h>
  37 #include <asm/uaccess.h>
  38
  39 #include <acpi/acpi_bus.h>
  40 #include <acpi/processor.h>
  41
  42 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  43 #define ACPI_PROCESSOR_CLASS            "processor"
  44 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  45 ACPI_MODULE_NAME("processor_throttling");
  46
  47 static int acpi_processor_get_throttling(struct acpi_processor *pr);
  48 int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
  49
  50 /*
  51  * _TPC - Throttling Present Capabilities
  52  */
  53 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
  54 {
  55         acpi_status status = 0;
  56         unsigned long tpc = 0;
  57
  58         if (!pr)
  59                 return -EINVAL;
  60         status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
  61         if (ACPI_FAILURE(status)) {
  62                 if (status != AE_NOT_FOUND) {
  63                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
  64                 }
  65                 return -ENODEV;
  66         }
  67         pr->throttling_platform_limit = (int)tpc;
  68         return 0;
  69 }
  70
  71 int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
  72 {
  73         int result = 0;
  74         int throttling_limit;
  75         int current_state;
  76         struct acpi_processor_limit *limit;
  77         int target_state;
  78
  79         result = acpi_processor_get_platform_limit(pr);
  80         if (result) {
  81                 /* Throttling Limit is unsupported */
  82                 return result;
  83         }
  84
  85         throttling_limit = pr->throttling_platform_limit;
  86         if (throttling_limit >= pr->throttling.state_count) {
  87                 /* Uncorrect Throttling Limit */
  88                 return -EINVAL;
  89         }
  90
  91         current_state = pr->throttling.state;
  92         if (current_state > throttling_limit) {
  93                 /*
  94                  * The current state can meet the requirement of
  95                  * _TPC limit. But it is reasonable that OSPM changes
  96                  * t-states from high to low for better performance.
  97                  * Of course the limit condition of thermal
  98                  * and user should be considered.
  99                  */
 100                 limit = &pr->limit;
 101                 target_state = throttling_limit;
 102                 if (limit->thermal.tx > target_state)
 103                         target_state = limit->thermal.tx;
 104                 if (limit->user.tx > target_state)
 105                         target_state = limit->user.tx;
 106         } else if (current_state == throttling_limit) {
 107                 /*
 108                  * Unnecessary to change the throttling state
 109                  */
 110                 return 0;
 111         } else {
 112                 /*
 113                  * If the current state is lower than the limit of _TPC, it
 114                  * will be forced to switch to the throttling state defined
 115                  * by throttling_platfor_limit.
 116                  * Because the previous state meets with the limit condition
 117                  * of thermal and user, it is unnecessary to check it again.
 118                  */
 119                 target_state = throttling_limit;
 120         }
 121         return acpi_processor_set_throttling(pr, target_state);
 122 }
 123
 124 /*
 125  * _PTC - Processor Throttling Control (and status) register location
 126  */
 127 static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
 128 {
 129         int result = 0;
 130         acpi_status status = 0;
 131         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 132         union acpi_object *ptc = NULL;
 133         union acpi_object obj = { 0 };
 134         struct acpi_processor_throttling *throttling;
 135
 136         status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
 137         if (ACPI_FAILURE(status)) {
 138                 if (status != AE_NOT_FOUND) {
 139                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
 140                 }
 141                 return -ENODEV;
 142         }
 143
 144         ptc = (union acpi_object *)buffer.pointer;
 145         if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
 146             || (ptc->package.count != 2)) {
 147                 printk(KERN_ERR PREFIX "Invalid _PTC data\n");
 148                 result = -EFAULT;
 149                 goto end;
 150         }
 151
 152         /*
 153          * control_register
 154          */
 155
 156         obj = ptc->package.elements[0];
 157
 158         if ((obj.type != ACPI_TYPE_BUFFER)
 159             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 160             || (obj.buffer.pointer == NULL)) {
 161                 printk(KERN_ERR PREFIX
 162                        "Invalid _PTC data (control_register)\n");
 163                 result = -EFAULT;
 164                 goto end;
 165         }
 166         memcpy(&pr->throttling.control_register, obj.buffer.pointer,
 167                sizeof(struct acpi_ptc_register));
 168
 169         /*
 170          * status_register
 171          */
 172
 173         obj = ptc->package.elements[1];
 174
 175         if ((obj.type != ACPI_TYPE_BUFFER)
 176             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 177             || (obj.buffer.pointer == NULL)) {
 178                 printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
 179                 result = -EFAULT;
 180                 goto end;
 181         }
 182
 183         memcpy(&pr->throttling.status_register, obj.buffer.pointer,
 184                sizeof(struct acpi_ptc_register));
 185
 186         throttling = &pr->throttling;
 187
 188         if ((throttling->control_register.bit_width +
 189                 throttling->control_register.bit_offset) > 32) {
 190                 printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
 191                 result = -EFAULT;
 192                 goto end;
 193         }
 194
 195         if ((throttling->status_register.bit_width +
 196                 throttling->status_register.bit_offset) > 32) {
 197                 printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
 198                 result = -EFAULT;
 199                 goto end;
 200         }
 201
 202       end:
 203         kfree(buffer.pointer);
 204
 205         return result;
 206 }
 207
 208 /*
 209  * _TSS - Throttling Supported States
 210  */
 211 static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 212 {
 213         int result = 0;
 214         acpi_status status = AE_OK;
 215         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 216         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 217         struct acpi_buffer state = { 0, NULL };
 218         union acpi_object *tss = NULL;
 219         int i;
 220
 221         status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
 222         if (ACPI_FAILURE(status)) {
 223                 if (status != AE_NOT_FOUND) {
 224                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
 225                 }
 226                 return -ENODEV;
 227         }
 228
 229         tss = buffer.pointer;
 230         if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
 231                 printk(KERN_ERR PREFIX "Invalid _TSS data\n");
 232                 result = -EFAULT;
 233                 goto end;
 234         }
 235
 236         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 237                           tss->package.count));
 238
 239         pr->throttling.state_count = tss->package.count;
 240         pr->throttling.states_tss =
 241             kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
 242                     GFP_KERNEL);
 243         if (!pr->throttling.states_tss) {
 244                 result = -ENOMEM;
 245                 goto end;
 246         }
 247
 248         for (i = 0; i < pr->throttling.state_count; i++) {
 249
 250                 struct acpi_processor_tx_tss *tx =
 251                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 252                                                       states_tss[i]);
 253
 254                 state.length = sizeof(struct acpi_processor_tx_tss);
 255                 state.pointer = tx;
 256
 257                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
 258
 259                 status = acpi_extract_package(&(tss->package.elements[i]),
 260                                               &format, &state);
 261                 if (ACPI_FAILURE(status)) {
 262                         ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
 263                         result = -EFAULT;
 264                         kfree(pr->throttling.states_tss);
 265                         goto end;
 266                 }
 267
 268                 if (!tx->freqpercentage) {
 269                         printk(KERN_ERR PREFIX
 270                                "Invalid _TSS data: freq is zero\n");
 271                         result = -EFAULT;
 272                         kfree(pr->throttling.states_tss);
 273                         goto end;
 274                 }
 275         }
 276
 277       end:
 278         kfree(buffer.pointer);
 279
 280         return result;
 281 }
 282
 283 /*
 284  * _TSD - T-State Dependencies
 285  */
 286 static int acpi_processor_get_tsd(struct acpi_processor *pr)
 287 {
 288         int result = 0;
 289         acpi_status status = AE_OK;
 290         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 291         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 292         struct acpi_buffer state = { 0, NULL };
 293         union acpi_object *tsd = NULL;
 294         struct acpi_tsd_package *pdomain;
 295
 296         status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
 297         if (ACPI_FAILURE(status)) {
 298                 if (status != AE_NOT_FOUND) {
 299                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
 300                 }
 301                 return -ENODEV;
 302         }
 303
 304         tsd = buffer.pointer;
 305         if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
 306                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 307                 result = -EFAULT;
 308                 goto end;
 309         }
 310
 311         if (tsd->package.count != 1) {
 312                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 313                 result = -EFAULT;
 314                 goto end;
 315         }
 316
 317         pdomain = &(pr->throttling.domain_info);
 318
 319         state.length = sizeof(struct acpi_tsd_package);
 320         state.pointer = pdomain;
 321
 322         status = acpi_extract_package(&(tsd->package.elements[0]),
 323                                       &format, &state);
 324         if (ACPI_FAILURE(status)) {
 325                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 326                 result = -EFAULT;
 327                 goto end;
 328         }
 329
 330         if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
 331                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:num_entries\n"));
 332                 result = -EFAULT;
 333                 goto end;
 334         }
 335
 336         if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
 337                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:revision\n"));
 338                 result = -EFAULT;
 339                 goto end;
 340         }
 341
 342       end:
 343         kfree(buffer.pointer);
 344         return result;
 345 }
 346
 347 /* --------------------------------------------------------------------------
 348                               Throttling Control
 349    -------------------------------------------------------------------------- */
 350 static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
 351 {
 352         int state = 0;
 353         u32 value = 0;
 354         u32 duty_mask = 0;
 355         u32 duty_value = 0;
 356
 357         if (!pr)
 358                 return -EINVAL;
 359
 360         if (!pr->flags.throttling)
 361                 return -ENODEV;
 362
 363         pr->throttling.state = 0;
 364
 365         duty_mask = pr->throttling.state_count - 1;
 366
 367         duty_mask <<= pr->throttling.duty_offset;
 368
 369         local_irq_disable();
 370
 371         value = inl(pr->throttling.address);
 372
 373         /*
 374          * Compute the current throttling state when throttling is enabled
 375          * (bit 4 is on).
 376          */
 377         if (value & 0x10) {
 378                 duty_value = value & duty_mask;
 379                 duty_value >>= pr->throttling.duty_offset;
 380
 381                 if (duty_value)
 382                         state = pr->throttling.state_count - duty_value;
 383         }
 384
 385         pr->throttling.state = state;
 386
 387         local_irq_enable();
 388
 389         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 390                           "Throttling state is T%d (%d%% throttling applied)\n",
 391                           state, pr->throttling.states[state].performance));
 392
 393         return 0;
 394 }
 395
 396 #ifdef CONFIG_X86
 397 static int acpi_throttling_rdmsr(struct acpi_processor *pr,
 398                                         acpi_integer * value)
 399 {
 400         struct cpuinfo_x86 *c;
 401         u64 msr_high, msr_low;
 402         unsigned int cpu;
 403         u64 msr = 0;
 404         int ret = -1;
 405
 406         cpu = pr->id;
 407         c = &cpu_data(cpu);
 408
 409         if ((c->x86_vendor != X86_VENDOR_INTEL) ||
 410                 !cpu_has(c, X86_FEATURE_ACPI)) {
 411                 printk(KERN_ERR PREFIX
 412                         "HARDWARE addr space,NOT supported yet\n");
 413         } else {
 414                 msr_low = 0;
 415                 msr_high = 0;
 416                 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL,
 417                         (u32 *)&msr_low , (u32 *) &msr_high);
 418                 msr = (msr_high << 32) | msr_low;
 419                 *value = (acpi_integer) msr;
 420                 ret = 0;
 421         }
 422         return ret;
 423 }
 424
 425 static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
 426 {
 427         struct cpuinfo_x86 *c;
 428         unsigned int cpu;
 429         int ret = -1;
 430         u64 msr;
 431
 432         cpu = pr->id;
 433         c = &cpu_data(cpu);
 434
 435         if ((c->x86_vendor != X86_VENDOR_INTEL) ||
 436                 !cpu_has(c, X86_FEATURE_ACPI)) {
 437                 printk(KERN_ERR PREFIX
 438                         "HARDWARE addr space,NOT supported yet\n");
 439         } else {
 440                 msr = value;
 441                 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL,
 442                         msr & 0xffffffff, msr >> 32);
 443                 ret = 0;
 444         }
 445         return ret;
 446 }
 447 #else
 448 static int acpi_throttling_rdmsr(struct acpi_processor *pr,
 449                                 acpi_integer * value)
 450 {
 451         printk(KERN_ERR PREFIX
 452                 "HARDWARE addr space,NOT supported yet\n");
 453         return -1;
 454 }
 455
 456 static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
 457 {
 458         printk(KERN_ERR PREFIX
 459                 "HARDWARE addr space,NOT supported yet\n");
 460         return -1;
 461 }
 462 #endif
 463
 464 static int acpi_read_throttling_status(struct acpi_processor *pr,
 465                                         acpi_integer *value)
 466 {
 467         u32 bit_width, bit_offset;
 468         u64 ptc_value;
 469         u64 ptc_mask;
 470         struct acpi_processor_throttling *throttling;
 471         int ret = -1;
 472
 473         throttling = &pr->throttling;
 474         switch (throttling->status_register.space_id) {
 475         case ACPI_ADR_SPACE_SYSTEM_IO:
 476                 ptc_value = 0;
 477                 bit_width = throttling->status_register.bit_width;
 478                 bit_offset = throttling->status_register.bit_offset;
 479
 480                 acpi_os_read_port((acpi_io_address) throttling->status_register.
 481                                   address, (u32 *) &ptc_value,
 482                                   (u32) (bit_width + bit_offset));
 483                 ptc_mask = (1 << bit_width) - 1;
 484                 *value = (acpi_integer) ((ptc_value >> bit_offset) & ptc_mask);
 485                 ret = 0;
 486                 break;
 487         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 488                 ret = acpi_throttling_rdmsr(pr, value);
 489                 break;
 490         default:
 491                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 492                        (u32) (throttling->status_register.space_id));
 493         }
 494         return ret;
 495 }
 496
 497 static int acpi_write_throttling_state(struct acpi_processor *pr,
 498                                 acpi_integer value)
 499 {
 500         u32 bit_width, bit_offset;
 501         u64 ptc_value;
 502         u64 ptc_mask;
 503         struct acpi_processor_throttling *throttling;
 504         int ret = -1;
 505
 506         throttling = &pr->throttling;
 507         switch (throttling->control_register.space_id) {
 508         case ACPI_ADR_SPACE_SYSTEM_IO:
 509                 bit_width = throttling->control_register.bit_width;
 510                 bit_offset = throttling->control_register.bit_offset;
 511                 ptc_mask = (1 << bit_width) - 1;
 512                 ptc_value = value & ptc_mask;
 513
 514                 acpi_os_write_port((acpi_io_address) throttling->
 515                                         control_register.address,
 516                                         (u32) (ptc_value << bit_offset),
 517                                         (u32) (bit_width + bit_offset));
 518                 ret = 0;
 519                 break;
 520         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 521                 ret = acpi_throttling_wrmsr(pr, value);
 522                 break;
 523         default:
 524                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 525                        (u32) (throttling->control_register.space_id));
 526         }
 527         return ret;
 528 }
 529
 530 static int acpi_get_throttling_state(struct acpi_processor *pr,
 531                                 acpi_integer value)
 532 {
 533         int i;
 534
 535         for (i = 0; i < pr->throttling.state_count; i++) {
 536                 struct acpi_processor_tx_tss *tx =
 537                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 538                                                       states_tss[i]);
 539                 if (tx->control == value)
 540                         break;
 541         }
 542         if (i > pr->throttling.state_count)
 543                 i = -1;
 544         return i;
 545 }
 546
 547 static int acpi_get_throttling_value(struct acpi_processor *pr,
 548                         int state, acpi_integer *value)
 549 {
 550         int ret = -1;
 551
 552         if (state >= 0 && state <= pr->throttling.state_count) {
 553                 struct acpi_processor_tx_tss *tx =
 554                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 555                                                       states_tss[state]);
 556                 *value = tx->control;
 557                 ret = 0;
 558         }
 559         return ret;
 560 }
 561
 562 static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
 563 {
 564         int state = 0;
 565         int ret;
 566         acpi_integer value;
 567
 568         if (!pr)
 569                 return -EINVAL;
 570
 571         if (!pr->flags.throttling)
 572                 return -ENODEV;
 573
 574         pr->throttling.state = 0;
 575         local_irq_disable();
 576         value = 0;
 577         ret = acpi_read_throttling_status(pr, &value);
 578         if (ret >= 0) {
 579                 state = acpi_get_throttling_state(pr, value);
 580                 pr->throttling.state = state;
 581         }
 582         local_irq_enable();
 583
 584         return 0;
 585 }
 586
 587 static int acpi_processor_get_throttling(struct acpi_processor *pr)
 588 {
 589         return pr->throttling.acpi_processor_get_throttling(pr);
 590 }
 591
 592 static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
 593 {
 594         int i, step;
 595
 596         if (!pr->throttling.address) {
 597                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
 598                 return -EINVAL;
 599         } else if (!pr->throttling.duty_width) {
 600                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
 601                 return -EINVAL;
 602         }
 603         /* TBD: Support duty_cycle values that span bit 4. */
 604         else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
 605                 printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
 606                 return -EINVAL;
 607         }
 608
 609         pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
 610
 611         /*
 612          * Compute state values. Note that throttling displays a linear power
 613          * performance relationship (at 50% performance the CPU will consume
 614          * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
 615          */
 616
 617         step = (1000 / pr->throttling.state_count);
 618
 619         for (i = 0; i < pr->throttling.state_count; i++) {
 620                 pr->throttling.states[i].performance = 1000 - step * i;
 621                 pr->throttling.states[i].power = 1000 - step * i;
 622         }
 623         return 0;
 624 }
 625
 626 static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
 627                                               int state)
 628 {
 629         u32 value = 0;
 630         u32 duty_mask = 0;
 631         u32 duty_value = 0;
 632
 633         if (!pr)
 634                 return -EINVAL;
 635
 636         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 637                 return -EINVAL;
 638
 639         if (!pr->flags.throttling)
 640                 return -ENODEV;
 641
 642         if (state == pr->throttling.state)
 643                 return 0;
 644
 645         if (state < pr->throttling_platform_limit)
 646                 return -EPERM;
 647         /*
 648          * Calculate the duty_value and duty_mask.
 649          */
 650         if (state) {
 651                 duty_value = pr->throttling.state_count - state;
 652
 653                 duty_value <<= pr->throttling.duty_offset;
 654
 655                 /* Used to clear all duty_value bits */
 656                 duty_mask = pr->throttling.state_count - 1;
 657
 658                 duty_mask <<= acpi_gbl_FADT.duty_offset;
 659                 duty_mask = ~duty_mask;
 660         }
 661
 662         local_irq_disable();
 663
 664         /*
 665          * Disable throttling by writing a 0 to bit 4.  Note that we must
 666          * turn it off before you can change the duty_value.
 667          */
 668         value = inl(pr->throttling.address);
 669         if (value & 0x10) {
 670                 value &= 0xFFFFFFEF;
 671                 outl(value, pr->throttling.address);
 672         }
 673
 674         /*
 675          * Write the new duty_value and then enable throttling.  Note
 676          * that a state value of 0 leaves throttling disabled.
 677          */
 678         if (state) {
 679                 value &= duty_mask;
 680                 value |= duty_value;
 681                 outl(value, pr->throttling.address);
 682
 683                 value |= 0x00000010;
 684                 outl(value, pr->throttling.address);
 685         }
 686
 687         pr->throttling.state = state;
 688
 689         local_irq_enable();
 690
 691         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 692                           "Throttling state set to T%d (%d%%)\n", state,
 693                           (pr->throttling.states[state].performance ? pr->
 694                            throttling.states[state].performance / 10 : 0)));
 695
 696         return 0;
 697 }
 698
 699 static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
 700                                              int state)
 701 {
 702         int ret;
 703         acpi_integer value;
 704
 705         if (!pr)
 706                 return -EINVAL;
 707
 708         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 709                 return -EINVAL;
 710
 711         if (!pr->flags.throttling)
 712                 return -ENODEV;
 713
 714         if (state == pr->throttling.state)
 715                 return 0;
 716
 717         if (state < pr->throttling_platform_limit)
 718                 return -EPERM;
 719
 720         local_irq_disable();
 721         value = 0;
 722         ret = acpi_get_throttling_value(pr, state, &value);
 723         if (ret >= 0) {
 724                 acpi_write_throttling_state(pr, value);
 725                 pr->throttling.state = state;
 726         }
 727         local_irq_enable();
 728
 729         return 0;
 730 }
 731
 732 int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 733 {
 734         return pr->throttling.acpi_processor_set_throttling(pr, state);
 735 }
 736
 737 int acpi_processor_get_throttling_info(struct acpi_processor *pr)
 738 {
 739         int result = 0;
 740
 741         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 742                           "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
 743                           pr->throttling.address,
 744                           pr->throttling.duty_offset,
 745                           pr->throttling.duty_width));
 746
 747         if (!pr)
 748                 return -EINVAL;
 749
 750         /*
 751          * Evaluate _PTC, _TSS and _TPC
 752          * They must all be present or none of them can be used.
 753          */
 754         if (acpi_processor_get_throttling_control(pr) ||
 755                 acpi_processor_get_throttling_states(pr) ||
 756                 acpi_processor_get_platform_limit(pr))
 757         {
 758                 if (acpi_processor_get_fadt_info(pr))
 759                         return 0;
 760                 pr->throttling.acpi_processor_get_throttling =
 761                     &acpi_processor_get_throttling_fadt;
 762                 pr->throttling.acpi_processor_set_throttling =
 763                     &acpi_processor_set_throttling_fadt;
 764         } else {
 765                 pr->throttling.acpi_processor_get_throttling =
 766                     &acpi_processor_get_throttling_ptc;
 767                 pr->throttling.acpi_processor_set_throttling =
 768                     &acpi_processor_set_throttling_ptc;
 769         }
 770
 771         acpi_processor_get_tsd(pr);
 772
 773         /*
 774          * PIIX4 Errata: We don't support throttling on the original PIIX4.
 775          * This shouldn't be an issue as few (if any) mobile systems ever
 776          * used this part.
 777          */
 778         if (errata.piix4.throttle) {
 779                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 780                                   "Throttling not supported on PIIX4 A- or B-step\n"));
 781                 return 0;
 782         }
 783
 784         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 785                           pr->throttling.state_count));
 786
 787         pr->flags.throttling = 1;
 788
 789         /*
 790          * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
 791          * thermal) decide to lower performance if it so chooses, but for now
 792          * we'll crank up the speed.
 793          */
 794
 795         result = acpi_processor_get_throttling(pr);
 796         if (result)
 797                 goto end;
 798
 799         if (pr->throttling.state) {
 800                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 801                                   "Disabling throttling (was T%d)\n",
 802                                   pr->throttling.state));
 803                 result = acpi_processor_set_throttling(pr, 0);
 804                 if (result)
 805                         goto end;
 806         }
 807
 808       end:
 809         if (result)
 810                 pr->flags.throttling = 0;
 811
 812         return result;
 813 }
 814
 815 /* proc interface */
 816
 817 static int acpi_processor_throttling_seq_show(struct seq_file *seq,
 818                                               void *offset)
 819 {
 820         struct acpi_processor *pr = seq->private;
 821         int i = 0;
 822         int result = 0;
 823
 824         if (!pr)
 825                 goto end;
 826
 827         if (!(pr->throttling.state_count > 0)) {
 828                 seq_puts(seq, "<not supported>\n");
 829                 goto end;
 830         }
 831
 832         result = acpi_processor_get_throttling(pr);
 833
 834         if (result) {
 835                 seq_puts(seq,
 836                          "Could not determine current throttling state.\n");
 837                 goto end;
 838         }
 839
 840         seq_printf(seq, "state count:             %d\n"
 841                    "active state:            T%d\n"
 842                    "state available: T%d to T%d\n",
 843                    pr->throttling.state_count, pr->throttling.state,
 844                    pr->throttling_platform_limit,
 845                    pr->throttling.state_count - 1);
 846
 847         seq_puts(seq, "states:\n");
 848         if (pr->throttling.acpi_processor_get_throttling ==
 849                         acpi_processor_get_throttling_fadt) {
 850                 for (i = 0; i < pr->throttling.state_count; i++)
 851                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 852                                    (i == pr->throttling.state ? '*' : ' '), i,
 853                                    (pr->throttling.states[i].performance ? pr->
 854                                     throttling.states[i].performance / 10 : 0));
 855         } else {
 856                 for (i = 0; i < pr->throttling.state_count; i++)
 857                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 858                                    (i == pr->throttling.state ? '*' : ' '), i,
 859                                    (int)pr->throttling.states_tss[i].
 860                                    freqpercentage);
 861         }
 862
 863       end:
 864         return 0;
 865 }
 866
 867 static int acpi_processor_throttling_open_fs(struct inode *inode,
 868                                              struct file *file)
 869 {
 870         return single_open(file, acpi_processor_throttling_seq_show,
 871                            PDE(inode)->data);
 872 }
 873
 874 static ssize_t acpi_processor_write_throttling(struct file *file,
 875                                                const char __user * buffer,
 876                                                size_t count, loff_t * data)
 877 {
 878         int result = 0;
 879         struct seq_file *m = file->private_data;
 880         struct acpi_processor *pr = m->private;
 881         char state_string[12] = { '\0' };
 882
 883         if (!pr || (count > sizeof(state_string) - 1))
 884                 return -EINVAL;
 885
 886         if (copy_from_user(state_string, buffer, count))
 887                 return -EFAULT;
 888
 889         state_string[count] = '\0';
 890
 891         result = acpi_processor_set_throttling(pr,
 892                                                simple_strtoul(state_string,
 893                                                               NULL, 0));
 894         if (result)
 895                 return result;
 896
 897         return count;
 898 }
 899
 900 struct file_operations acpi_processor_throttling_fops = {
 901         .open = acpi_processor_throttling_open_fs,
 902         .read = seq_read,
 903         .write = acpi_processor_write_throttling,
 904         .llseek = seq_lseek,
 905         .release = single_release,
 906 };