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 static int acpi_read_throttling_status(struct acpi_processor *pr,
 397                                         acpi_integer *value)
 398 {
 399         u32 bit_width, bit_offset;
 400         u64 ptc_value;
 401         u64 ptc_mask;
 402         struct acpi_processor_throttling *throttling;
 403         int ret = -1;
 404
 405         throttling = &pr->throttling;
 406         switch (throttling->status_register.space_id) {
 407         case ACPI_ADR_SPACE_SYSTEM_IO:
 408                 ptc_value = 0;
 409                 bit_width = throttling->status_register.bit_width;
 410                 bit_offset = throttling->status_register.bit_offset;
 411
 412                 acpi_os_read_port((acpi_io_address) throttling->status_register.
 413                                   address, (u32 *) &ptc_value,
 414                                   (u32) (bit_width + bit_offset));
 415                 ptc_mask = (1 << bit_width) - 1;
 416                 *value = (acpi_integer) ((ptc_value >> bit_offset) & ptc_mask);
 417                 ret = 0;
 418                 break;
 419         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 420                 printk(KERN_ERR PREFIX
 421                        "HARDWARE addr space,NOT supported yet\n");
 422                 break;
 423         default:
 424                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 425                        (u32) (throttling->status_register.space_id));
 426         }
 427         return ret;
 428 }
 429
 430 static int acpi_write_throttling_state(struct acpi_processor *pr,
 431                                 acpi_integer value)
 432 {
 433         u32 bit_width, bit_offset;
 434         u64 ptc_value;
 435         u64 ptc_mask;
 436         struct acpi_processor_throttling *throttling;
 437         int ret = -1;
 438
 439         throttling = &pr->throttling;
 440         switch (throttling->control_register.space_id) {
 441         case ACPI_ADR_SPACE_SYSTEM_IO:
 442                 bit_width = throttling->control_register.bit_width;
 443                 bit_offset = throttling->control_register.bit_offset;
 444                 ptc_mask = (1 << bit_width) - 1;
 445                 ptc_value = value & ptc_mask;
 446
 447                 acpi_os_write_port((acpi_io_address) throttling->
 448                                         control_register.address,
 449                                         (u32) (ptc_value << bit_offset),
 450                                         (u32) (bit_width + bit_offset));
 451                 ret = 0;
 452                 break;
 453         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 454                 printk(KERN_ERR PREFIX
 455                        "HARDWARE addr space,NOT supported yet\n");
 456                 break;
 457         default:
 458                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 459                        (u32) (throttling->control_register.space_id));
 460         }
 461         return ret;
 462 }
 463
 464 static int acpi_get_throttling_state(struct acpi_processor *pr,
 465                                 acpi_integer value)
 466 {
 467         int i;
 468
 469         for (i = 0; i < pr->throttling.state_count; i++) {
 470                 struct acpi_processor_tx_tss *tx =
 471                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 472                                                       states_tss[i]);
 473                 if (tx->control == value)
 474                         break;
 475         }
 476         if (i > pr->throttling.state_count)
 477                 i = -1;
 478         return i;
 479 }
 480
 481 static int acpi_get_throttling_value(struct acpi_processor *pr,
 482                         int state, acpi_integer *value)
 483 {
 484         int ret = -1;
 485
 486         if (state >= 0 && state <= pr->throttling.state_count) {
 487                 struct acpi_processor_tx_tss *tx =
 488                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 489                                                       states_tss[state]);
 490                 *value = tx->control;
 491                 ret = 0;
 492         }
 493         return ret;
 494 }
 495
 496 static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
 497 {
 498         int state = 0;
 499         int ret;
 500         acpi_integer value;
 501
 502         if (!pr)
 503                 return -EINVAL;
 504
 505         if (!pr->flags.throttling)
 506                 return -ENODEV;
 507
 508         pr->throttling.state = 0;
 509         local_irq_disable();
 510         value = 0;
 511         ret = acpi_read_throttling_status(pr, &value);
 512         if (ret >= 0) {
 513                 state = acpi_get_throttling_state(pr, value);
 514                 pr->throttling.state = state;
 515         }
 516         local_irq_enable();
 517
 518         return 0;
 519 }
 520
 521 static int acpi_processor_get_throttling(struct acpi_processor *pr)
 522 {
 523         return pr->throttling.acpi_processor_get_throttling(pr);
 524 }
 525
 526 static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
 527 {
 528         int i, step;
 529
 530         if (!pr->throttling.address) {
 531                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
 532                 return -EINVAL;
 533         } else if (!pr->throttling.duty_width) {
 534                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
 535                 return -EINVAL;
 536         }
 537         /* TBD: Support duty_cycle values that span bit 4. */
 538         else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
 539                 printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
 540                 return -EINVAL;
 541         }
 542
 543         pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
 544
 545         /*
 546          * Compute state values. Note that throttling displays a linear power
 547          * performance relationship (at 50% performance the CPU will consume
 548          * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
 549          */
 550
 551         step = (1000 / pr->throttling.state_count);
 552
 553         for (i = 0; i < pr->throttling.state_count; i++) {
 554                 pr->throttling.states[i].performance = 1000 - step * i;
 555                 pr->throttling.states[i].power = 1000 - step * i;
 556         }
 557         return 0;
 558 }
 559
 560 static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
 561                                               int state)
 562 {
 563         u32 value = 0;
 564         u32 duty_mask = 0;
 565         u32 duty_value = 0;
 566
 567         if (!pr)
 568                 return -EINVAL;
 569
 570         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 571                 return -EINVAL;
 572
 573         if (!pr->flags.throttling)
 574                 return -ENODEV;
 575
 576         if (state == pr->throttling.state)
 577                 return 0;
 578
 579         if (state < pr->throttling_platform_limit)
 580                 return -EPERM;
 581         /*
 582          * Calculate the duty_value and duty_mask.
 583          */
 584         if (state) {
 585                 duty_value = pr->throttling.state_count - state;
 586
 587                 duty_value <<= pr->throttling.duty_offset;
 588
 589                 /* Used to clear all duty_value bits */
 590                 duty_mask = pr->throttling.state_count - 1;
 591
 592                 duty_mask <<= acpi_gbl_FADT.duty_offset;
 593                 duty_mask = ~duty_mask;
 594         }
 595
 596         local_irq_disable();
 597
 598         /*
 599          * Disable throttling by writing a 0 to bit 4.  Note that we must
 600          * turn it off before you can change the duty_value.
 601          */
 602         value = inl(pr->throttling.address);
 603         if (value & 0x10) {
 604                 value &= 0xFFFFFFEF;
 605                 outl(value, pr->throttling.address);
 606         }
 607
 608         /*
 609          * Write the new duty_value and then enable throttling.  Note
 610          * that a state value of 0 leaves throttling disabled.
 611          */
 612         if (state) {
 613                 value &= duty_mask;
 614                 value |= duty_value;
 615                 outl(value, pr->throttling.address);
 616
 617                 value |= 0x00000010;
 618                 outl(value, pr->throttling.address);
 619         }
 620
 621         pr->throttling.state = state;
 622
 623         local_irq_enable();
 624
 625         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 626                           "Throttling state set to T%d (%d%%)\n", state,
 627                           (pr->throttling.states[state].performance ? pr->
 628                            throttling.states[state].performance / 10 : 0)));
 629
 630         return 0;
 631 }
 632
 633 static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
 634                                              int state)
 635 {
 636         int ret;
 637         acpi_integer value;
 638
 639         if (!pr)
 640                 return -EINVAL;
 641
 642         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 643                 return -EINVAL;
 644
 645         if (!pr->flags.throttling)
 646                 return -ENODEV;
 647
 648         if (state == pr->throttling.state)
 649                 return 0;
 650
 651         if (state < pr->throttling_platform_limit)
 652                 return -EPERM;
 653
 654         local_irq_disable();
 655         value = 0;
 656         ret = acpi_get_throttling_value(pr, state, &value);
 657         if (ret >= 0) {
 658                 acpi_write_throttling_state(pr, value);
 659                 pr->throttling.state = state;
 660         }
 661         local_irq_enable();
 662
 663         return 0;
 664 }
 665
 666 int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 667 {
 668         return pr->throttling.acpi_processor_set_throttling(pr, state);
 669 }
 670
 671 int acpi_processor_get_throttling_info(struct acpi_processor *pr)
 672 {
 673         int result = 0;
 674
 675         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 676                           "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
 677                           pr->throttling.address,
 678                           pr->throttling.duty_offset,
 679                           pr->throttling.duty_width));
 680
 681         if (!pr)
 682                 return -EINVAL;
 683
 684         /*
 685          * Evaluate _PTC, _TSS and _TPC
 686          * They must all be present or none of them can be used.
 687          */
 688         if (acpi_processor_get_throttling_control(pr) ||
 689                 acpi_processor_get_throttling_states(pr) ||
 690                 acpi_processor_get_platform_limit(pr))
 691         {
 692                 if (acpi_processor_get_fadt_info(pr))
 693                         return 0;
 694                 pr->throttling.acpi_processor_get_throttling =
 695                     &acpi_processor_get_throttling_fadt;
 696                 pr->throttling.acpi_processor_set_throttling =
 697                     &acpi_processor_set_throttling_fadt;
 698         } else {
 699                 pr->throttling.acpi_processor_get_throttling =
 700                     &acpi_processor_get_throttling_ptc;
 701                 pr->throttling.acpi_processor_set_throttling =
 702                     &acpi_processor_set_throttling_ptc;
 703         }
 704
 705         acpi_processor_get_tsd(pr);
 706
 707         /*
 708          * PIIX4 Errata: We don't support throttling on the original PIIX4.
 709          * This shouldn't be an issue as few (if any) mobile systems ever
 710          * used this part.
 711          */
 712         if (errata.piix4.throttle) {
 713                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 714                                   "Throttling not supported on PIIX4 A- or B-step\n"));
 715                 return 0;
 716         }
 717
 718         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 719                           pr->throttling.state_count));
 720
 721         pr->flags.throttling = 1;
 722
 723         /*
 724          * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
 725          * thermal) decide to lower performance if it so chooses, but for now
 726          * we'll crank up the speed.
 727          */
 728
 729         result = acpi_processor_get_throttling(pr);
 730         if (result)
 731                 goto end;
 732
 733         if (pr->throttling.state) {
 734                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 735                                   "Disabling throttling (was T%d)\n",
 736                                   pr->throttling.state));
 737                 result = acpi_processor_set_throttling(pr, 0);
 738                 if (result)
 739                         goto end;
 740         }
 741
 742       end:
 743         if (result)
 744                 pr->flags.throttling = 0;
 745
 746         return result;
 747 }
 748
 749 /* proc interface */
 750
 751 static int acpi_processor_throttling_seq_show(struct seq_file *seq,
 752                                               void *offset)
 753 {
 754         struct acpi_processor *pr = seq->private;
 755         int i = 0;
 756         int result = 0;
 757
 758         if (!pr)
 759                 goto end;
 760
 761         if (!(pr->throttling.state_count > 0)) {
 762                 seq_puts(seq, "<not supported>\n");
 763                 goto end;
 764         }
 765
 766         result = acpi_processor_get_throttling(pr);
 767
 768         if (result) {
 769                 seq_puts(seq,
 770                          "Could not determine current throttling state.\n");
 771                 goto end;
 772         }
 773
 774         seq_printf(seq, "state count:             %d\n"
 775                    "active state:            T%d\n"
 776                    "state available: T%d to T%d\n",
 777                    pr->throttling.state_count, pr->throttling.state,
 778                    pr->throttling_platform_limit,
 779                    pr->throttling.state_count - 1);
 780
 781         seq_puts(seq, "states:\n");
 782         if (pr->throttling.acpi_processor_get_throttling ==
 783                         acpi_processor_get_throttling_fadt) {
 784                 for (i = 0; i < pr->throttling.state_count; i++)
 785                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 786                                    (i == pr->throttling.state ? '*' : ' '), i,
 787                                    (pr->throttling.states[i].performance ? pr->
 788                                     throttling.states[i].performance / 10 : 0));
 789         } else {
 790                 for (i = 0; i < pr->throttling.state_count; i++)
 791                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 792                                    (i == pr->throttling.state ? '*' : ' '), i,
 793                                    (int)pr->throttling.states_tss[i].
 794                                    freqpercentage);
 795         }
 796
 797       end:
 798         return 0;
 799 }
 800
 801 static int acpi_processor_throttling_open_fs(struct inode *inode,
 802                                              struct file *file)
 803 {
 804         return single_open(file, acpi_processor_throttling_seq_show,
 805                            PDE(inode)->data);
 806 }
 807
 808 static ssize_t acpi_processor_write_throttling(struct file *file,
 809                                                const char __user * buffer,
 810                                                size_t count, loff_t * data)
 811 {
 812         int result = 0;
 813         struct seq_file *m = file->private_data;
 814         struct acpi_processor *pr = m->private;
 815         char state_string[12] = { '\0' };
 816
 817         if (!pr || (count > sizeof(state_string) - 1))
 818                 return -EINVAL;
 819
 820         if (copy_from_user(state_string, buffer, count))
 821                 return -EFAULT;
 822
 823         state_string[count] = '\0';
 824
 825         result = acpi_processor_set_throttling(pr,
 826                                                simple_strtoul(state_string,
 827                                                               NULL, 0));
 828         if (result)
 829                 return result;
 830
 831         return count;
 832 }
 833
 834 struct file_operations acpi_processor_throttling_fops = {
 835         .open = acpi_processor_throttling_open_fs,
 836         .read = seq_read,
 837         .write = acpi_processor_write_throttling,
 838         .llseek = seq_lseek,
 839         .release = single_release,
 840 };