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
 135         status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
 136         if (ACPI_FAILURE(status)) {
 137                 if (status != AE_NOT_FOUND) {
 138                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
 139                 }
 140                 return -ENODEV;
 141         }
 142
 143         ptc = (union acpi_object *)buffer.pointer;
 144         if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
 145             || (ptc->package.count != 2)) {
 146                 printk(KERN_ERR PREFIX "Invalid _PTC data\n");
 147                 result = -EFAULT;
 148                 goto end;
 149         }
 150
 151         /*
 152          * control_register
 153          */
 154
 155         obj = ptc->package.elements[0];
 156
 157         if ((obj.type != ACPI_TYPE_BUFFER)
 158             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 159             || (obj.buffer.pointer == NULL)) {
 160                 printk(KERN_ERR PREFIX
 161                        "Invalid _PTC data (control_register)\n");
 162                 result = -EFAULT;
 163                 goto end;
 164         }
 165         memcpy(&pr->throttling.control_register, obj.buffer.pointer,
 166                sizeof(struct acpi_ptc_register));
 167
 168         /*
 169          * status_register
 170          */
 171
 172         obj = ptc->package.elements[1];
 173
 174         if ((obj.type != ACPI_TYPE_BUFFER)
 175             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 176             || (obj.buffer.pointer == NULL)) {
 177                 printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
 178                 result = -EFAULT;
 179                 goto end;
 180         }
 181
 182         memcpy(&pr->throttling.status_register, obj.buffer.pointer,
 183                sizeof(struct acpi_ptc_register));
 184
 185       end:
 186         kfree(buffer.pointer);
 187
 188         return result;
 189 }
 190
 191 /*
 192  * _TSS - Throttling Supported States
 193  */
 194 static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 195 {
 196         int result = 0;
 197         acpi_status status = AE_OK;
 198         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 199         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 200         struct acpi_buffer state = { 0, NULL };
 201         union acpi_object *tss = NULL;
 202         int i;
 203
 204         status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
 205         if (ACPI_FAILURE(status)) {
 206                 if (status != AE_NOT_FOUND) {
 207                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
 208                 }
 209                 return -ENODEV;
 210         }
 211
 212         tss = buffer.pointer;
 213         if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
 214                 printk(KERN_ERR PREFIX "Invalid _TSS data\n");
 215                 result = -EFAULT;
 216                 goto end;
 217         }
 218
 219         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 220                           tss->package.count));
 221
 222         pr->throttling.state_count = tss->package.count;
 223         pr->throttling.states_tss =
 224             kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
 225                     GFP_KERNEL);
 226         if (!pr->throttling.states_tss) {
 227                 result = -ENOMEM;
 228                 goto end;
 229         }
 230
 231         for (i = 0; i < pr->throttling.state_count; i++) {
 232
 233                 struct acpi_processor_tx_tss *tx =
 234                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 235                                                       states_tss[i]);
 236
 237                 state.length = sizeof(struct acpi_processor_tx_tss);
 238                 state.pointer = tx;
 239
 240                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
 241
 242                 status = acpi_extract_package(&(tss->package.elements[i]),
 243                                               &format, &state);
 244                 if (ACPI_FAILURE(status)) {
 245                         ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
 246                         result = -EFAULT;
 247                         kfree(pr->throttling.states_tss);
 248                         goto end;
 249                 }
 250
 251                 if (!tx->freqpercentage) {
 252                         printk(KERN_ERR PREFIX
 253                                "Invalid _TSS data: freq is zero\n");
 254                         result = -EFAULT;
 255                         kfree(pr->throttling.states_tss);
 256                         goto end;
 257                 }
 258         }
 259
 260       end:
 261         kfree(buffer.pointer);
 262
 263         return result;
 264 }
 265
 266 /*
 267  * _TSD - T-State Dependencies
 268  */
 269 static int acpi_processor_get_tsd(struct acpi_processor *pr)
 270 {
 271         int result = 0;
 272         acpi_status status = AE_OK;
 273         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 274         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 275         struct acpi_buffer state = { 0, NULL };
 276         union acpi_object *tsd = NULL;
 277         struct acpi_tsd_package *pdomain;
 278
 279         status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
 280         if (ACPI_FAILURE(status)) {
 281                 if (status != AE_NOT_FOUND) {
 282                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
 283                 }
 284                 return -ENODEV;
 285         }
 286
 287         tsd = buffer.pointer;
 288         if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
 289                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 290                 result = -EFAULT;
 291                 goto end;
 292         }
 293
 294         if (tsd->package.count != 1) {
 295                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 296                 result = -EFAULT;
 297                 goto end;
 298         }
 299
 300         pdomain = &(pr->throttling.domain_info);
 301
 302         state.length = sizeof(struct acpi_tsd_package);
 303         state.pointer = pdomain;
 304
 305         status = acpi_extract_package(&(tsd->package.elements[0]),
 306                                       &format, &state);
 307         if (ACPI_FAILURE(status)) {
 308                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 309                 result = -EFAULT;
 310                 goto end;
 311         }
 312
 313         if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
 314                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:num_entries\n"));
 315                 result = -EFAULT;
 316                 goto end;
 317         }
 318
 319         if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
 320                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:revision\n"));
 321                 result = -EFAULT;
 322                 goto end;
 323         }
 324
 325       end:
 326         kfree(buffer.pointer);
 327         return result;
 328 }
 329
 330 /* --------------------------------------------------------------------------
 331                               Throttling Control
 332    -------------------------------------------------------------------------- */
 333 static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
 334 {
 335         int state = 0;
 336         u32 value = 0;
 337         u32 duty_mask = 0;
 338         u32 duty_value = 0;
 339
 340         if (!pr)
 341                 return -EINVAL;
 342
 343         if (!pr->flags.throttling)
 344                 return -ENODEV;
 345
 346         pr->throttling.state = 0;
 347
 348         duty_mask = pr->throttling.state_count - 1;
 349
 350         duty_mask <<= pr->throttling.duty_offset;
 351
 352         local_irq_disable();
 353
 354         value = inl(pr->throttling.address);
 355
 356         /*
 357          * Compute the current throttling state when throttling is enabled
 358          * (bit 4 is on).
 359          */
 360         if (value & 0x10) {
 361                 duty_value = value & duty_mask;
 362                 duty_value >>= pr->throttling.duty_offset;
 363
 364                 if (duty_value)
 365                         state = pr->throttling.state_count - duty_value;
 366         }
 367
 368         pr->throttling.state = state;
 369
 370         local_irq_enable();
 371
 372         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 373                           "Throttling state is T%d (%d%% throttling applied)\n",
 374                           state, pr->throttling.states[state].performance));
 375
 376         return 0;
 377 }
 378
 379 static int acpi_read_throttling_status(struct acpi_processor *pr,
 380                                         acpi_integer *value)
 381 {
 382         u64 ptc_value;
 383         struct acpi_processor_throttling *throttling;
 384         int ret = -1;
 385
 386         throttling = &pr->throttling;
 387         switch (throttling->status_register.space_id) {
 388         case ACPI_ADR_SPACE_SYSTEM_IO:
 389                 ptc_value = 0;
 390                 acpi_os_read_port((acpi_io_address) throttling->status_register.
 391                                   address, (u32 *) &ptc_value,
 392                                   (u32) throttling->status_register.bit_width *
 393                                   8);
 394                 *value = (acpi_integer) ptc_value;
 395                 ret = 0;
 396                 break;
 397         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 398                 printk(KERN_ERR PREFIX
 399                        "HARDWARE addr space,NOT supported yet\n");
 400                 break;
 401         default:
 402                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 403                        (u32) (throttling->status_register.space_id));
 404         }
 405         return ret;
 406 }
 407
 408 static int acpi_write_throttling_state(struct acpi_processor *pr,
 409                                 acpi_integer value)
 410 {
 411         u64 ptc_value;
 412         struct acpi_processor_throttling *throttling;
 413         int ret = -1;
 414
 415         throttling = &pr->throttling;
 416         switch (throttling->control_register.space_id) {
 417         case ACPI_ADR_SPACE_SYSTEM_IO:
 418                 ptc_value = value;
 419                 acpi_os_write_port((acpi_io_address) throttling->
 420                                    control_register.address, (u32) ptc_value,
 421                                    (u32) throttling->control_register.
 422                                    bit_width * 8);
 423                 ret = 0;
 424                 break;
 425         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 426                 printk(KERN_ERR PREFIX
 427                        "HARDWARE addr space,NOT supported yet\n");
 428                 break;
 429         default:
 430                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 431                        (u32) (throttling->control_register.space_id));
 432         }
 433         return ret;
 434 }
 435
 436 static int acpi_get_throttling_state(struct acpi_processor *pr,
 437                                 acpi_integer value)
 438 {
 439         int i;
 440
 441         for (i = 0; i < pr->throttling.state_count; i++) {
 442                 struct acpi_processor_tx_tss *tx =
 443                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 444                                                       states_tss[i]);
 445                 if (tx->control == value)
 446                         break;
 447         }
 448         if (i > pr->throttling.state_count)
 449                 i = -1;
 450         return i;
 451 }
 452
 453 static int acpi_get_throttling_value(struct acpi_processor *pr,
 454                         int state, acpi_integer *value)
 455 {
 456         int ret = -1;
 457
 458         if (state >= 0 && state <= pr->throttling.state_count) {
 459                 struct acpi_processor_tx_tss *tx =
 460                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 461                                                       states_tss[state]);
 462                 *value = tx->control;
 463                 ret = 0;
 464         }
 465         return ret;
 466 }
 467
 468 static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
 469 {
 470         int state = 0;
 471         int ret;
 472         acpi_integer value;
 473
 474         if (!pr)
 475                 return -EINVAL;
 476
 477         if (!pr->flags.throttling)
 478                 return -ENODEV;
 479
 480         pr->throttling.state = 0;
 481         local_irq_disable();
 482         value = 0;
 483         ret = acpi_read_throttling_status(pr, &value);
 484         if (ret >= 0) {
 485                 state = acpi_get_throttling_state(pr, value);
 486                 pr->throttling.state = state;
 487         }
 488         local_irq_enable();
 489
 490         return 0;
 491 }
 492
 493 static int acpi_processor_get_throttling(struct acpi_processor *pr)
 494 {
 495         return pr->throttling.acpi_processor_get_throttling(pr);
 496 }
 497
 498 static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
 499 {
 500         int i, step;
 501
 502         if (!pr->throttling.address) {
 503                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
 504                 return -EINVAL;
 505         } else if (!pr->throttling.duty_width) {
 506                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
 507                 return -EINVAL;
 508         }
 509         /* TBD: Support duty_cycle values that span bit 4. */
 510         else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
 511                 printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
 512                 return -EINVAL;
 513         }
 514
 515         pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
 516
 517         /*
 518          * Compute state values. Note that throttling displays a linear power
 519          * performance relationship (at 50% performance the CPU will consume
 520          * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
 521          */
 522
 523         step = (1000 / pr->throttling.state_count);
 524
 525         for (i = 0; i < pr->throttling.state_count; i++) {
 526                 pr->throttling.states[i].performance = 1000 - step * i;
 527                 pr->throttling.states[i].power = 1000 - step * i;
 528         }
 529         return 0;
 530 }
 531
 532 static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
 533                                               int state)
 534 {
 535         u32 value = 0;
 536         u32 duty_mask = 0;
 537         u32 duty_value = 0;
 538
 539         if (!pr)
 540                 return -EINVAL;
 541
 542         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 543                 return -EINVAL;
 544
 545         if (!pr->flags.throttling)
 546                 return -ENODEV;
 547
 548         if (state == pr->throttling.state)
 549                 return 0;
 550
 551         if (state < pr->throttling_platform_limit)
 552                 return -EPERM;
 553         /*
 554          * Calculate the duty_value and duty_mask.
 555          */
 556         if (state) {
 557                 duty_value = pr->throttling.state_count - state;
 558
 559                 duty_value <<= pr->throttling.duty_offset;
 560
 561                 /* Used to clear all duty_value bits */
 562                 duty_mask = pr->throttling.state_count - 1;
 563
 564                 duty_mask <<= acpi_gbl_FADT.duty_offset;
 565                 duty_mask = ~duty_mask;
 566         }
 567
 568         local_irq_disable();
 569
 570         /*
 571          * Disable throttling by writing a 0 to bit 4.  Note that we must
 572          * turn it off before you can change the duty_value.
 573          */
 574         value = inl(pr->throttling.address);
 575         if (value & 0x10) {
 576                 value &= 0xFFFFFFEF;
 577                 outl(value, pr->throttling.address);
 578         }
 579
 580         /*
 581          * Write the new duty_value and then enable throttling.  Note
 582          * that a state value of 0 leaves throttling disabled.
 583          */
 584         if (state) {
 585                 value &= duty_mask;
 586                 value |= duty_value;
 587                 outl(value, pr->throttling.address);
 588
 589                 value |= 0x00000010;
 590                 outl(value, pr->throttling.address);
 591         }
 592
 593         pr->throttling.state = state;
 594
 595         local_irq_enable();
 596
 597         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 598                           "Throttling state set to T%d (%d%%)\n", state,
 599                           (pr->throttling.states[state].performance ? pr->
 600                            throttling.states[state].performance / 10 : 0)));
 601
 602         return 0;
 603 }
 604
 605 static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
 606                                              int state)
 607 {
 608         int ret;
 609         acpi_integer value;
 610
 611         if (!pr)
 612                 return -EINVAL;
 613
 614         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 615                 return -EINVAL;
 616
 617         if (!pr->flags.throttling)
 618                 return -ENODEV;
 619
 620         if (state == pr->throttling.state)
 621                 return 0;
 622
 623         if (state < pr->throttling_platform_limit)
 624                 return -EPERM;
 625
 626         local_irq_disable();
 627         value = 0;
 628         ret = acpi_get_throttling_value(pr, state, &value);
 629         if (ret >= 0) {
 630                 acpi_write_throttling_state(pr, value);
 631                 pr->throttling.state = state;
 632         }
 633         local_irq_enable();
 634
 635         return 0;
 636 }
 637
 638 int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 639 {
 640         return pr->throttling.acpi_processor_set_throttling(pr, state);
 641 }
 642
 643 int acpi_processor_get_throttling_info(struct acpi_processor *pr)
 644 {
 645         int result = 0;
 646
 647         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 648                           "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
 649                           pr->throttling.address,
 650                           pr->throttling.duty_offset,
 651                           pr->throttling.duty_width));
 652
 653         if (!pr)
 654                 return -EINVAL;
 655
 656         /*
 657          * Evaluate _PTC, _TSS and _TPC
 658          * They must all be present or none of them can be used.
 659          */
 660         if (acpi_processor_get_throttling_control(pr) ||
 661                 acpi_processor_get_throttling_states(pr) ||
 662                 acpi_processor_get_platform_limit(pr))
 663         {
 664                 if (acpi_processor_get_fadt_info(pr))
 665                         return 0;
 666                 pr->throttling.acpi_processor_get_throttling =
 667                     &acpi_processor_get_throttling_fadt;
 668                 pr->throttling.acpi_processor_set_throttling =
 669                     &acpi_processor_set_throttling_fadt;
 670         } else {
 671                 pr->throttling.acpi_processor_get_throttling =
 672                     &acpi_processor_get_throttling_ptc;
 673                 pr->throttling.acpi_processor_set_throttling =
 674                     &acpi_processor_set_throttling_ptc;
 675         }
 676
 677         acpi_processor_get_tsd(pr);
 678
 679         /*
 680          * PIIX4 Errata: We don't support throttling on the original PIIX4.
 681          * This shouldn't be an issue as few (if any) mobile systems ever
 682          * used this part.
 683          */
 684         if (errata.piix4.throttle) {
 685                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 686                                   "Throttling not supported on PIIX4 A- or B-step\n"));
 687                 return 0;
 688         }
 689
 690         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 691                           pr->throttling.state_count));
 692
 693         pr->flags.throttling = 1;
 694
 695         /*
 696          * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
 697          * thermal) decide to lower performance if it so chooses, but for now
 698          * we'll crank up the speed.
 699          */
 700
 701         result = acpi_processor_get_throttling(pr);
 702         if (result)
 703                 goto end;
 704
 705         if (pr->throttling.state) {
 706                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 707                                   "Disabling throttling (was T%d)\n",
 708                                   pr->throttling.state));
 709                 result = acpi_processor_set_throttling(pr, 0);
 710                 if (result)
 711                         goto end;
 712         }
 713
 714       end:
 715         if (result)
 716                 pr->flags.throttling = 0;
 717
 718         return result;
 719 }
 720
 721 /* proc interface */
 722
 723 static int acpi_processor_throttling_seq_show(struct seq_file *seq,
 724                                               void *offset)
 725 {
 726         struct acpi_processor *pr = seq->private;
 727         int i = 0;
 728         int result = 0;
 729
 730         if (!pr)
 731                 goto end;
 732
 733         if (!(pr->throttling.state_count > 0)) {
 734                 seq_puts(seq, "<not supported>\n");
 735                 goto end;
 736         }
 737
 738         result = acpi_processor_get_throttling(pr);
 739
 740         if (result) {
 741                 seq_puts(seq,
 742                          "Could not determine current throttling state.\n");
 743                 goto end;
 744         }
 745
 746         seq_printf(seq, "state count:             %d\n"
 747                    "active state:            T%d\n"
 748                    "state available: T%d to T%d\n",
 749                    pr->throttling.state_count, pr->throttling.state,
 750                    pr->throttling_platform_limit,
 751                    pr->throttling.state_count - 1);
 752
 753         seq_puts(seq, "states:\n");
 754         if (pr->throttling.acpi_processor_get_throttling ==
 755                         acpi_processor_get_throttling_fadt) {
 756                 for (i = 0; i < pr->throttling.state_count; i++)
 757                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 758                                    (i == pr->throttling.state ? '*' : ' '), i,
 759                                    (pr->throttling.states[i].performance ? pr->
 760                                     throttling.states[i].performance / 10 : 0));
 761         } else {
 762                 for (i = 0; i < pr->throttling.state_count; i++)
 763                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 764                                    (i == pr->throttling.state ? '*' : ' '), i,
 765                                    (int)pr->throttling.states_tss[i].
 766                                    freqpercentage);
 767         }
 768
 769       end:
 770         return 0;
 771 }
 772
 773 static int acpi_processor_throttling_open_fs(struct inode *inode,
 774                                              struct file *file)
 775 {
 776         return single_open(file, acpi_processor_throttling_seq_show,
 777                            PDE(inode)->data);
 778 }
 779
 780 static ssize_t acpi_processor_write_throttling(struct file *file,
 781                                                const char __user * buffer,
 782                                                size_t count, loff_t * data)
 783 {
 784         int result = 0;
 785         struct seq_file *m = file->private_data;
 786         struct acpi_processor *pr = m->private;
 787         char state_string[12] = { '\0' };
 788
 789         if (!pr || (count > sizeof(state_string) - 1))
 790                 return -EINVAL;
 791
 792         if (copy_from_user(state_string, buffer, count))
 793                 return -EFAULT;
 794
 795         state_string[count] = '\0';
 796
 797         result = acpi_processor_set_throttling(pr,
 798                                                simple_strtoul(state_string,
 799                                                               NULL, 0));
 800         if (result)
 801                 return result;
 802
 803         return count;
 804 }
 805
 806 struct file_operations acpi_processor_throttling_fops = {
 807         .open = acpi_processor_throttling_open_fs,
 808         .read = seq_read,
 809         .write = acpi_processor_write_throttling,
 810         .llseek = seq_lseek,
 811         .release = single_release,
 812 };