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   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/sched.h>
  33 #include <linux/cpufreq.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/seq_file.h>
  36
  37 #include <asm/io.h>
  38 #include <asm/uaccess.h>
  39
  40 #include <acpi/acpi_bus.h>
  41 #include <acpi/processor.h>
  42
  43 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  44 #define ACPI_PROCESSOR_CLASS            "processor"
  45 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  46 ACPI_MODULE_NAME("processor_throttling");
  47
  48 static int acpi_processor_get_throttling(struct acpi_processor *pr);
  49 int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
  50
  51 /*
  52  * _TPC - Throttling Present Capabilities
  53  */
  54 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
  55 {
  56         acpi_status status = 0;
  57         unsigned long tpc = 0;
  58
  59         if (!pr)
  60                 return -EINVAL;
  61         status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
  62         if (ACPI_FAILURE(status)) {
  63                 if (status != AE_NOT_FOUND) {
  64                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
  65                 }
  66                 return -ENODEV;
  67         }
  68         pr->throttling_platform_limit = (int)tpc;
  69         return 0;
  70 }
  71
  72 int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
  73 {
  74         int result = 0;
  75         int throttling_limit;
  76         int current_state;
  77         struct acpi_processor_limit *limit;
  78         int target_state;
  79
  80         result = acpi_processor_get_platform_limit(pr);
  81         if (result) {
  82                 /* Throttling Limit is unsupported */
  83                 return result;
  84         }
  85
  86         throttling_limit = pr->throttling_platform_limit;
  87         if (throttling_limit >= pr->throttling.state_count) {
  88                 /* Uncorrect Throttling Limit */
  89                 return -EINVAL;
  90         }
  91
  92         current_state = pr->throttling.state;
  93         if (current_state > throttling_limit) {
  94                 /*
  95                  * The current state can meet the requirement of
  96                  * _TPC limit. But it is reasonable that OSPM changes
  97                  * t-states from high to low for better performance.
  98                  * Of course the limit condition of thermal
  99                  * and user should be considered.
 100                  */
 101                 limit = &pr->limit;
 102                 target_state = throttling_limit;
 103                 if (limit->thermal.tx > target_state)
 104                         target_state = limit->thermal.tx;
 105                 if (limit->user.tx > target_state)
 106                         target_state = limit->user.tx;
 107         } else if (current_state == throttling_limit) {
 108                 /*
 109                  * Unnecessary to change the throttling state
 110                  */
 111                 return 0;
 112         } else {
 113                 /*
 114                  * If the current state is lower than the limit of _TPC, it
 115                  * will be forced to switch to the throttling state defined
 116                  * by throttling_platfor_limit.
 117                  * Because the previous state meets with the limit condition
 118                  * of thermal and user, it is unnecessary to check it again.
 119                  */
 120                 target_state = throttling_limit;
 121         }
 122         return acpi_processor_set_throttling(pr, target_state);
 123 }
 124
 125 /*
 126  * _PTC - Processor Throttling Control (and status) register location
 127  */
 128 static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
 129 {
 130         int result = 0;
 131         acpi_status status = 0;
 132         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 133         union acpi_object *ptc = NULL;
 134         union acpi_object obj = { 0 };
 135         struct acpi_processor_throttling *throttling;
 136
 137         status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
 138         if (ACPI_FAILURE(status)) {
 139                 if (status != AE_NOT_FOUND) {
 140                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
 141                 }
 142                 return -ENODEV;
 143         }
 144
 145         ptc = (union acpi_object *)buffer.pointer;
 146         if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
 147             || (ptc->package.count != 2)) {
 148                 printk(KERN_ERR PREFIX "Invalid _PTC data\n");
 149                 result = -EFAULT;
 150                 goto end;
 151         }
 152
 153         /*
 154          * control_register
 155          */
 156
 157         obj = ptc->package.elements[0];
 158
 159         if ((obj.type != ACPI_TYPE_BUFFER)
 160             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 161             || (obj.buffer.pointer == NULL)) {
 162                 printk(KERN_ERR PREFIX
 163                        "Invalid _PTC data (control_register)\n");
 164                 result = -EFAULT;
 165                 goto end;
 166         }
 167         memcpy(&pr->throttling.control_register, obj.buffer.pointer,
 168                sizeof(struct acpi_ptc_register));
 169
 170         /*
 171          * status_register
 172          */
 173
 174         obj = ptc->package.elements[1];
 175
 176         if ((obj.type != ACPI_TYPE_BUFFER)
 177             || (obj.buffer.length < sizeof(struct acpi_ptc_register))
 178             || (obj.buffer.pointer == NULL)) {
 179                 printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
 180                 result = -EFAULT;
 181                 goto end;
 182         }
 183
 184         memcpy(&pr->throttling.status_register, obj.buffer.pointer,
 185                sizeof(struct acpi_ptc_register));
 186
 187         throttling = &pr->throttling;
 188
 189         if ((throttling->control_register.bit_width +
 190                 throttling->control_register.bit_offset) > 32) {
 191                 printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
 192                 result = -EFAULT;
 193                 goto end;
 194         }
 195
 196         if ((throttling->status_register.bit_width +
 197                 throttling->status_register.bit_offset) > 32) {
 198                 printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
 199                 result = -EFAULT;
 200                 goto end;
 201         }
 202
 203       end:
 204         kfree(buffer.pointer);
 205
 206         return result;
 207 }
 208
 209 /*
 210  * _TSS - Throttling Supported States
 211  */
 212 static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 213 {
 214         int result = 0;
 215         acpi_status status = AE_OK;
 216         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 217         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 218         struct acpi_buffer state = { 0, NULL };
 219         union acpi_object *tss = NULL;
 220         int i;
 221
 222         status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
 223         if (ACPI_FAILURE(status)) {
 224                 if (status != AE_NOT_FOUND) {
 225                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
 226                 }
 227                 return -ENODEV;
 228         }
 229
 230         tss = buffer.pointer;
 231         if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
 232                 printk(KERN_ERR PREFIX "Invalid _TSS data\n");
 233                 result = -EFAULT;
 234                 goto end;
 235         }
 236
 237         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 238                           tss->package.count));
 239
 240         pr->throttling.state_count = tss->package.count;
 241         pr->throttling.states_tss =
 242             kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
 243                     GFP_KERNEL);
 244         if (!pr->throttling.states_tss) {
 245                 result = -ENOMEM;
 246                 goto end;
 247         }
 248
 249         for (i = 0; i < pr->throttling.state_count; i++) {
 250
 251                 struct acpi_processor_tx_tss *tx =
 252                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 253                                                       states_tss[i]);
 254
 255                 state.length = sizeof(struct acpi_processor_tx_tss);
 256                 state.pointer = tx;
 257
 258                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
 259
 260                 status = acpi_extract_package(&(tss->package.elements[i]),
 261                                               &format, &state);
 262                 if (ACPI_FAILURE(status)) {
 263                         ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
 264                         result = -EFAULT;
 265                         kfree(pr->throttling.states_tss);
 266                         goto end;
 267                 }
 268
 269                 if (!tx->freqpercentage) {
 270                         printk(KERN_ERR PREFIX
 271                                "Invalid _TSS data: freq is zero\n");
 272                         result = -EFAULT;
 273                         kfree(pr->throttling.states_tss);
 274                         goto end;
 275                 }
 276         }
 277
 278       end:
 279         kfree(buffer.pointer);
 280
 281         return result;
 282 }
 283
 284 /*
 285  * _TSD - T-State Dependencies
 286  */
 287 static int acpi_processor_get_tsd(struct acpi_processor *pr)
 288 {
 289         int result = 0;
 290         acpi_status status = AE_OK;
 291         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 292         struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
 293         struct acpi_buffer state = { 0, NULL };
 294         union acpi_object *tsd = NULL;
 295         struct acpi_tsd_package *pdomain;
 296
 297         status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
 298         if (ACPI_FAILURE(status)) {
 299                 if (status != AE_NOT_FOUND) {
 300                         ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
 301                 }
 302                 return -ENODEV;
 303         }
 304
 305         tsd = buffer.pointer;
 306         if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
 307                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 308                 result = -EFAULT;
 309                 goto end;
 310         }
 311
 312         if (tsd->package.count != 1) {
 313                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 314                 result = -EFAULT;
 315                 goto end;
 316         }
 317
 318         pdomain = &(pr->throttling.domain_info);
 319
 320         state.length = sizeof(struct acpi_tsd_package);
 321         state.pointer = pdomain;
 322
 323         status = acpi_extract_package(&(tsd->package.elements[0]),
 324                                       &format, &state);
 325         if (ACPI_FAILURE(status)) {
 326                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
 327                 result = -EFAULT;
 328                 goto end;
 329         }
 330
 331         if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
 332                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:num_entries\n"));
 333                 result = -EFAULT;
 334                 goto end;
 335         }
 336
 337         if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
 338                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:revision\n"));
 339                 result = -EFAULT;
 340                 goto end;
 341         }
 342
 343       end:
 344         kfree(buffer.pointer);
 345         return result;
 346 }
 347
 348 /* --------------------------------------------------------------------------
 349                               Throttling Control
 350    -------------------------------------------------------------------------- */
 351 static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
 352 {
 353         int state = 0;
 354         u32 value = 0;
 355         u32 duty_mask = 0;
 356         u32 duty_value = 0;
 357
 358         if (!pr)
 359                 return -EINVAL;
 360
 361         if (!pr->flags.throttling)
 362                 return -ENODEV;
 363
 364         pr->throttling.state = 0;
 365
 366         duty_mask = pr->throttling.state_count - 1;
 367
 368         duty_mask <<= pr->throttling.duty_offset;
 369
 370         local_irq_disable();
 371
 372         value = inl(pr->throttling.address);
 373
 374         /*
 375          * Compute the current throttling state when throttling is enabled
 376          * (bit 4 is on).
 377          */
 378         if (value & 0x10) {
 379                 duty_value = value & duty_mask;
 380                 duty_value >>= pr->throttling.duty_offset;
 381
 382                 if (duty_value)
 383                         state = pr->throttling.state_count - duty_value;
 384         }
 385
 386         pr->throttling.state = state;
 387
 388         local_irq_enable();
 389
 390         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 391                           "Throttling state is T%d (%d%% throttling applied)\n",
 392                           state, pr->throttling.states[state].performance));
 393
 394         return 0;
 395 }
 396
 397 #ifdef CONFIG_X86
 398 static int acpi_throttling_rdmsr(struct acpi_processor *pr,
 399                                         acpi_integer * value)
 400 {
 401         struct cpuinfo_x86 *c;
 402         u64 msr_high, msr_low;
 403         unsigned int cpu;
 404         u64 msr = 0;
 405         int ret = -1;
 406
 407         cpu = pr->id;
 408         c = &cpu_data(cpu);
 409
 410         if ((c->x86_vendor != X86_VENDOR_INTEL) ||
 411                 !cpu_has(c, X86_FEATURE_ACPI)) {
 412                 printk(KERN_ERR PREFIX
 413                         "HARDWARE addr space,NOT supported yet\n");
 414         } else {
 415                 msr_low = 0;
 416                 msr_high = 0;
 417                 rdmsr_safe(MSR_IA32_THERM_CONTROL,
 418                         (u32 *)&msr_low , (u32 *) &msr_high);
 419                 msr = (msr_high << 32) | msr_low;
 420                 *value = (acpi_integer) msr;
 421                 ret = 0;
 422         }
 423         return ret;
 424 }
 425
 426 static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
 427 {
 428         struct cpuinfo_x86 *c;
 429         unsigned int cpu;
 430         int ret = -1;
 431         u64 msr;
 432
 433         cpu = pr->id;
 434         c = &cpu_data(cpu);
 435
 436         if ((c->x86_vendor != X86_VENDOR_INTEL) ||
 437                 !cpu_has(c, X86_FEATURE_ACPI)) {
 438                 printk(KERN_ERR PREFIX
 439                         "HARDWARE addr space,NOT supported yet\n");
 440         } else {
 441                 msr = value;
 442                 wrmsr_safe(MSR_IA32_THERM_CONTROL,
 443                         msr & 0xffffffff, msr >> 32);
 444                 ret = 0;
 445         }
 446         return ret;
 447 }
 448 #else
 449 static int acpi_throttling_rdmsr(struct acpi_processor *pr,
 450                                 acpi_integer * value)
 451 {
 452         printk(KERN_ERR PREFIX
 453                 "HARDWARE addr space,NOT supported yet\n");
 454         return -1;
 455 }
 456
 457 static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
 458 {
 459         printk(KERN_ERR PREFIX
 460                 "HARDWARE addr space,NOT supported yet\n");
 461         return -1;
 462 }
 463 #endif
 464
 465 static int acpi_read_throttling_status(struct acpi_processor *pr,
 466                                         acpi_integer *value)
 467 {
 468         u32 bit_width, bit_offset;
 469         u64 ptc_value;
 470         u64 ptc_mask;
 471         struct acpi_processor_throttling *throttling;
 472         int ret = -1;
 473
 474         throttling = &pr->throttling;
 475         switch (throttling->status_register.space_id) {
 476         case ACPI_ADR_SPACE_SYSTEM_IO:
 477                 ptc_value = 0;
 478                 bit_width = throttling->status_register.bit_width;
 479                 bit_offset = throttling->status_register.bit_offset;
 480
 481                 acpi_os_read_port((acpi_io_address) throttling->status_register.
 482                                   address, (u32 *) &ptc_value,
 483                                   (u32) (bit_width + bit_offset));
 484                 ptc_mask = (1 << bit_width) - 1;
 485                 *value = (acpi_integer) ((ptc_value >> bit_offset) & ptc_mask);
 486                 ret = 0;
 487                 break;
 488         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 489                 ret = acpi_throttling_rdmsr(pr, value);
 490                 break;
 491         default:
 492                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 493                        (u32) (throttling->status_register.space_id));
 494         }
 495         return ret;
 496 }
 497
 498 static int acpi_write_throttling_state(struct acpi_processor *pr,
 499                                 acpi_integer value)
 500 {
 501         u32 bit_width, bit_offset;
 502         u64 ptc_value;
 503         u64 ptc_mask;
 504         struct acpi_processor_throttling *throttling;
 505         int ret = -1;
 506
 507         throttling = &pr->throttling;
 508         switch (throttling->control_register.space_id) {
 509         case ACPI_ADR_SPACE_SYSTEM_IO:
 510                 bit_width = throttling->control_register.bit_width;
 511                 bit_offset = throttling->control_register.bit_offset;
 512                 ptc_mask = (1 << bit_width) - 1;
 513                 ptc_value = value & ptc_mask;
 514
 515                 acpi_os_write_port((acpi_io_address) throttling->
 516                                         control_register.address,
 517                                         (u32) (ptc_value << bit_offset),
 518                                         (u32) (bit_width + bit_offset));
 519                 ret = 0;
 520                 break;
 521         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 522                 ret = acpi_throttling_wrmsr(pr, value);
 523                 break;
 524         default:
 525                 printk(KERN_ERR PREFIX "Unknown addr space %d\n",
 526                        (u32) (throttling->control_register.space_id));
 527         }
 528         return ret;
 529 }
 530
 531 static int acpi_get_throttling_state(struct acpi_processor *pr,
 532                                 acpi_integer value)
 533 {
 534         int i;
 535
 536         for (i = 0; i < pr->throttling.state_count; i++) {
 537                 struct acpi_processor_tx_tss *tx =
 538                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 539                                                       states_tss[i]);
 540                 if (tx->control == value)
 541                         break;
 542         }
 543         if (i > pr->throttling.state_count)
 544                 i = -1;
 545         return i;
 546 }
 547
 548 static int acpi_get_throttling_value(struct acpi_processor *pr,
 549                         int state, acpi_integer *value)
 550 {
 551         int ret = -1;
 552
 553         if (state >= 0 && state <= pr->throttling.state_count) {
 554                 struct acpi_processor_tx_tss *tx =
 555                     (struct acpi_processor_tx_tss *)&(pr->throttling.
 556                                                       states_tss[state]);
 557                 *value = tx->control;
 558                 ret = 0;
 559         }
 560         return ret;
 561 }
 562
 563 static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
 564 {
 565         int state = 0;
 566         int ret;
 567         acpi_integer value;
 568
 569         if (!pr)
 570                 return -EINVAL;
 571
 572         if (!pr->flags.throttling)
 573                 return -ENODEV;
 574
 575         pr->throttling.state = 0;
 576
 577         value = 0;
 578         ret = acpi_read_throttling_status(pr, &value);
 579         if (ret >= 0) {
 580                 state = acpi_get_throttling_state(pr, value);
 581                 pr->throttling.state = state;
 582         }
 583
 584         return 0;
 585 }
 586
 587 static int acpi_processor_get_throttling(struct acpi_processor *pr)
 588 {
 589         cpumask_t saved_mask;
 590         int ret;
 591
 592         /*
 593          * Migrate task to the cpu pointed by pr.
 594          */
 595         saved_mask = current->cpus_allowed;
 596         set_cpus_allowed(current, cpumask_of_cpu(pr->id));
 597         ret = pr->throttling.acpi_processor_get_throttling(pr);
 598         /* restore the previous state */
 599         set_cpus_allowed(current, saved_mask);
 600
 601         return ret;
 602 }
 603
 604 static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
 605 {
 606         int i, step;
 607
 608         if (!pr->throttling.address) {
 609                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
 610                 return -EINVAL;
 611         } else if (!pr->throttling.duty_width) {
 612                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
 613                 return -EINVAL;
 614         }
 615         /* TBD: Support duty_cycle values that span bit 4. */
 616         else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
 617                 printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
 618                 return -EINVAL;
 619         }
 620
 621         pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
 622
 623         /*
 624          * Compute state values. Note that throttling displays a linear power
 625          * performance relationship (at 50% performance the CPU will consume
 626          * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
 627          */
 628
 629         step = (1000 / pr->throttling.state_count);
 630
 631         for (i = 0; i < pr->throttling.state_count; i++) {
 632                 pr->throttling.states[i].performance = 1000 - step * i;
 633                 pr->throttling.states[i].power = 1000 - step * i;
 634         }
 635         return 0;
 636 }
 637
 638 static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
 639                                               int state)
 640 {
 641         u32 value = 0;
 642         u32 duty_mask = 0;
 643         u32 duty_value = 0;
 644
 645         if (!pr)
 646                 return -EINVAL;
 647
 648         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 649                 return -EINVAL;
 650
 651         if (!pr->flags.throttling)
 652                 return -ENODEV;
 653
 654         if (state == pr->throttling.state)
 655                 return 0;
 656
 657         if (state < pr->throttling_platform_limit)
 658                 return -EPERM;
 659         /*
 660          * Calculate the duty_value and duty_mask.
 661          */
 662         if (state) {
 663                 duty_value = pr->throttling.state_count - state;
 664
 665                 duty_value <<= pr->throttling.duty_offset;
 666
 667                 /* Used to clear all duty_value bits */
 668                 duty_mask = pr->throttling.state_count - 1;
 669
 670                 duty_mask <<= acpi_gbl_FADT.duty_offset;
 671                 duty_mask = ~duty_mask;
 672         }
 673
 674         local_irq_disable();
 675
 676         /*
 677          * Disable throttling by writing a 0 to bit 4.  Note that we must
 678          * turn it off before you can change the duty_value.
 679          */
 680         value = inl(pr->throttling.address);
 681         if (value & 0x10) {
 682                 value &= 0xFFFFFFEF;
 683                 outl(value, pr->throttling.address);
 684         }
 685
 686         /*
 687          * Write the new duty_value and then enable throttling.  Note
 688          * that a state value of 0 leaves throttling disabled.
 689          */
 690         if (state) {
 691                 value &= duty_mask;
 692                 value |= duty_value;
 693                 outl(value, pr->throttling.address);
 694
 695                 value |= 0x00000010;
 696                 outl(value, pr->throttling.address);
 697         }
 698
 699         pr->throttling.state = state;
 700
 701         local_irq_enable();
 702
 703         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 704                           "Throttling state set to T%d (%d%%)\n", state,
 705                           (pr->throttling.states[state].performance ? pr->
 706                            throttling.states[state].performance / 10 : 0)));
 707
 708         return 0;
 709 }
 710
 711 static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
 712                                              int state)
 713 {
 714         int ret;
 715         acpi_integer value;
 716
 717         if (!pr)
 718                 return -EINVAL;
 719
 720         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
 721                 return -EINVAL;
 722
 723         if (!pr->flags.throttling)
 724                 return -ENODEV;
 725
 726         if (state == pr->throttling.state)
 727                 return 0;
 728
 729         if (state < pr->throttling_platform_limit)
 730                 return -EPERM;
 731
 732         value = 0;
 733         ret = acpi_get_throttling_value(pr, state, &value);
 734         if (ret >= 0) {
 735                 acpi_write_throttling_state(pr, value);
 736                 pr->throttling.state = state;
 737         }
 738
 739         return 0;
 740 }
 741
 742 int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 743 {
 744         cpumask_t saved_mask;
 745         int ret;
 746         /*
 747          * Migrate task to the cpu pointed by pr.
 748          */
 749         saved_mask = current->cpus_allowed;
 750         set_cpus_allowed(current, cpumask_of_cpu(pr->id));
 751         ret = pr->throttling.acpi_processor_set_throttling(pr, state);
 752         /* restore the previous state */
 753         set_cpus_allowed(current, saved_mask);
 754         return ret;
 755 }
 756
 757 int acpi_processor_get_throttling_info(struct acpi_processor *pr)
 758 {
 759         int result = 0;
 760
 761         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 762                           "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
 763                           pr->throttling.address,
 764                           pr->throttling.duty_offset,
 765                           pr->throttling.duty_width));
 766
 767         if (!pr)
 768                 return -EINVAL;
 769
 770         /*
 771          * Evaluate _PTC, _TSS and _TPC
 772          * They must all be present or none of them can be used.
 773          */
 774         if (acpi_processor_get_throttling_control(pr) ||
 775                 acpi_processor_get_throttling_states(pr) ||
 776                 acpi_processor_get_platform_limit(pr))
 777         {
 778                 pr->throttling.acpi_processor_get_throttling =
 779                     &acpi_processor_get_throttling_fadt;
 780                 pr->throttling.acpi_processor_set_throttling =
 781                     &acpi_processor_set_throttling_fadt;
 782                 if (acpi_processor_get_fadt_info(pr))
 783                         return 0;
 784         } else {
 785                 pr->throttling.acpi_processor_get_throttling =
 786                     &acpi_processor_get_throttling_ptc;
 787                 pr->throttling.acpi_processor_set_throttling =
 788                     &acpi_processor_set_throttling_ptc;
 789         }
 790
 791         acpi_processor_get_tsd(pr);
 792
 793         /*
 794          * PIIX4 Errata: We don't support throttling on the original PIIX4.
 795          * This shouldn't be an issue as few (if any) mobile systems ever
 796          * used this part.
 797          */
 798         if (errata.piix4.throttle) {
 799                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 800                                   "Throttling not supported on PIIX4 A- or B-step\n"));
 801                 return 0;
 802         }
 803
 804         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
 805                           pr->throttling.state_count));
 806
 807         pr->flags.throttling = 1;
 808
 809         /*
 810          * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
 811          * thermal) decide to lower performance if it so chooses, but for now
 812          * we'll crank up the speed.
 813          */
 814
 815         result = acpi_processor_get_throttling(pr);
 816         if (result)
 817                 goto end;
 818
 819         if (pr->throttling.state) {
 820                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 821                                   "Disabling throttling (was T%d)\n",
 822                                   pr->throttling.state));
 823                 result = acpi_processor_set_throttling(pr, 0);
 824                 if (result)
 825                         goto end;
 826         }
 827
 828       end:
 829         if (result)
 830                 pr->flags.throttling = 0;
 831
 832         return result;
 833 }
 834
 835 /* proc interface */
 836
 837 static int acpi_processor_throttling_seq_show(struct seq_file *seq,
 838                                               void *offset)
 839 {
 840         struct acpi_processor *pr = seq->private;
 841         int i = 0;
 842         int result = 0;
 843
 844         if (!pr)
 845                 goto end;
 846
 847         if (!(pr->throttling.state_count > 0)) {
 848                 seq_puts(seq, "<not supported>\n");
 849                 goto end;
 850         }
 851
 852         result = acpi_processor_get_throttling(pr);
 853
 854         if (result) {
 855                 seq_puts(seq,
 856                          "Could not determine current throttling state.\n");
 857                 goto end;
 858         }
 859
 860         seq_printf(seq, "state count:             %d\n"
 861                    "active state:            T%d\n"
 862                    "state available: T%d to T%d\n",
 863                    pr->throttling.state_count, pr->throttling.state,
 864                    pr->throttling_platform_limit,
 865                    pr->throttling.state_count - 1);
 866
 867         seq_puts(seq, "states:\n");
 868         if (pr->throttling.acpi_processor_get_throttling ==
 869                         acpi_processor_get_throttling_fadt) {
 870                 for (i = 0; i < pr->throttling.state_count; i++)
 871                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 872                                    (i == pr->throttling.state ? '*' : ' '), i,
 873                                    (pr->throttling.states[i].performance ? pr->
 874                                     throttling.states[i].performance / 10 : 0));
 875         } else {
 876                 for (i = 0; i < pr->throttling.state_count; i++)
 877                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
 878                                    (i == pr->throttling.state ? '*' : ' '), i,
 879                                    (int)pr->throttling.states_tss[i].
 880                                    freqpercentage);
 881         }
 882
 883       end:
 884         return 0;
 885 }
 886
 887 static int acpi_processor_throttling_open_fs(struct inode *inode,
 888                                              struct file *file)
 889 {
 890         return single_open(file, acpi_processor_throttling_seq_show,
 891                            PDE(inode)->data);
 892 }
 893
 894 static ssize_t acpi_processor_write_throttling(struct file *file,
 895                                                const char __user * buffer,
 896                                                size_t count, loff_t * data)
 897 {
 898         int result = 0;
 899         struct seq_file *m = file->private_data;
 900         struct acpi_processor *pr = m->private;
 901         char state_string[12] = { '\0' };
 902
 903         if (!pr || (count > sizeof(state_string) - 1))
 904                 return -EINVAL;
 905
 906         if (copy_from_user(state_string, buffer, count))
 907                 return -EFAULT;
 908
 909         state_string[count] = '\0';
 910
 911         result = acpi_processor_set_throttling(pr,
 912                                                simple_strtoul(state_string,
 913                                                               NULL, 0));
 914         if (result)
 915                 return result;
 916
 917         return count;
 918 }
 919
 920 struct file_operations acpi_processor_throttling_fops = {
 921         .open = acpi_processor_throttling_open_fs,
 922         .read = seq_read,
 923         .write = acpi_processor_write_throttling,
 924         .llseek = seq_lseek,
 925         .release = single_release,
 926 };