drivers/acpi/processor_idle.c

   1 /*
   2  * processor_idle - idle state submodule to 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 #include <linux/acpi.h>
  36 #include <linux/dmi.h>
  37 #include <linux/moduleparam.h>
  38
  39 #include <asm/io.h>
  40 #include <asm/uaccess.h>
  41
  42 #include <acpi/acpi_bus.h>
  43 #include <acpi/processor.h>
  44
  45 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  46 #define ACPI_PROCESSOR_CLASS            "processor"
  47 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
  48 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  49 ACPI_MODULE_NAME                ("acpi_processor")
  50
  51 #define ACPI_PROCESSOR_FILE_POWER       "power"
  52
  53 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  54 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  55 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  56
  57 static void (*pm_idle_save)(void);
  58 module_param(max_cstate, uint, 0644);
  59
  60 static unsigned int nocst = 0;
  61 module_param(nocst, uint, 0000);
  62
  63 /*
  64  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  65  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  66  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  67  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  68  * reduce history for more aggressive entry into C3
  69  */
  70 static unsigned int bm_history = (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  71 module_param(bm_history, uint, 0644);
  72 /* --------------------------------------------------------------------------
  73                                 Power Management
  74    -------------------------------------------------------------------------- */
  75
  76 /*
  77  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  78  * For now disable this. Probably a bug somewhere else.
  79  *
  80  * To skip this limit, boot/load with a large max_cstate limit.
  81  */
  82 static int no_c2c3(struct dmi_system_id *id)
  83 {
  84         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  85                 return 0;
  86
  87         printk(KERN_NOTICE PREFIX "%s detected - C2,C3 disabled."
  88                 " Override with \"processor.max_cstate=%d\"\n", id->ident,
  89                ACPI_PROCESSOR_MAX_POWER + 1);
  90
  91         max_cstate = 1;
  92
  93         return 0;
  94 }
  95
  96
  97
  98
  99 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
 100         { no_c2c3, "IBM ThinkPad R40e", {
 101           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 102           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }},
 103         { no_c2c3, "Medion 41700", {
 104           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 105           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J") }},
 106         {},
 107 };
 108
 109
 110 static inline u32
 111 ticks_elapsed (
 112         u32                     t1,
 113         u32                     t2)
 114 {
 115         if (t2 >= t1)
 116                 return (t2 - t1);
 117         else if (!acpi_fadt.tmr_val_ext)
 118                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 119         else
 120                 return ((0xFFFFFFFF - t1) + t2);
 121 }
 122
 123
 124 static void
 125 acpi_processor_power_activate (
 126         struct acpi_processor   *pr,
 127         struct acpi_processor_cx  *new)
 128 {
 129         struct acpi_processor_cx  *old;
 130
 131         if (!pr || !new)
 132                 return;
 133
 134         old = pr->power.state;
 135
 136         if (old)
 137                 old->promotion.count = 0;
 138         new->demotion.count = 0;
 139
 140         /* Cleanup from old state. */
 141         if (old) {
 142                 switch (old->type) {
 143                 case ACPI_STATE_C3:
 144                         /* Disable bus master reload */
 145                         if (new->type != ACPI_STATE_C3)
 146                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0, ACPI_MTX_DO_NOT_LOCK);
 147                         break;
 148                 }
 149         }
 150
 151         /* Prepare to use new state. */
 152         switch (new->type) {
 153         case ACPI_STATE_C3:
 154                 /* Enable bus master reload */
 155                 if (old->type != ACPI_STATE_C3)
 156                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1, ACPI_MTX_DO_NOT_LOCK);
 157                 break;
 158         }
 159
 160         pr->power.state = new;
 161
 162         return;
 163 }
 164
 165
 166 static void acpi_processor_idle (void)
 167 {
 168         struct acpi_processor   *pr = NULL;
 169         struct acpi_processor_cx *cx = NULL;
 170         struct acpi_processor_cx *next_state = NULL;
 171         int                     sleep_ticks = 0;
 172         u32                     t1, t2 = 0;
 173
 174         pr = processors[raw_smp_processor_id()];
 175         if (!pr)
 176                 return;
 177
 178         /*
 179          * Interrupts must be disabled during bus mastering calculations and
 180          * for C2/C3 transitions.
 181          */
 182         local_irq_disable();
 183
 184         /*
 185          * Check whether we truly need to go idle, or should
 186          * reschedule:
 187          */
 188         if (unlikely(need_resched())) {
 189                 local_irq_enable();
 190                 return;
 191         }
 192
 193         cx = pr->power.state;
 194         if (!cx)
 195                 goto easy_out;
 196
 197         /*
 198          * Check BM Activity
 199          * -----------------
 200          * Check for bus mastering activity (if required), record, and check
 201          * for demotion.
 202          */
 203         if (pr->flags.bm_check) {
 204                 u32             bm_status = 0;
 205                 unsigned long   diff = jiffies - pr->power.bm_check_timestamp;
 206
 207                 if (diff > 32)
 208                         diff = 32;
 209
 210                 while (diff) {
 211                         /* if we didn't get called, assume there was busmaster activity */
 212                         diff--;
 213                         if (diff)
 214                                 pr->power.bm_activity |= 0x1;
 215                         pr->power.bm_activity <<= 1;
 216                 }
 217
 218                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 219                         &bm_status, ACPI_MTX_DO_NOT_LOCK);
 220                 if (bm_status) {
 221                         pr->power.bm_activity++;
 222                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 223                                 1, ACPI_MTX_DO_NOT_LOCK);
 224                 }
 225                 /*
 226                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 227                  * the true state of bus mastering activity; forcing us to
 228                  * manually check the BMIDEA bit of each IDE channel.
 229                  */
 230                 else if (errata.piix4.bmisx) {
 231                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 232                                 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 233                                 pr->power.bm_activity++;
 234                 }
 235
 236                 pr->power.bm_check_timestamp = jiffies;
 237
 238                 /*
 239                  * Apply bus mastering demotion policy.  Automatically demote
 240                  * to avoid a faulty transition.  Note that the processor
 241                  * won't enter a low-power state during this call (to this
 242                  * funciton) but should upon the next.
 243                  *
 244                  * TBD: A better policy might be to fallback to the demotion
 245                  *      state (use it for this quantum only) istead of
 246                  *      demoting -- and rely on duration as our sole demotion
 247                  *      qualification.  This may, however, introduce DMA
 248                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 249                  */
 250                 if (pr->power.bm_activity & cx->demotion.threshold.bm) {
 251                         local_irq_enable();
 252                         next_state = cx->demotion.state;
 253                         goto end;
 254                 }
 255         }
 256
 257         cx->usage++;
 258
 259         /*
 260          * Sleep:
 261          * ------
 262          * Invoke the current Cx state to put the processor to sleep.
 263          */
 264         switch (cx->type) {
 265
 266         case ACPI_STATE_C1:
 267                 /*
 268                  * Invoke C1.
 269                  * Use the appropriate idle routine, the one that would
 270                  * be used without acpi C-states.
 271                  */
 272                 if (pm_idle_save)
 273                         pm_idle_save();
 274                 else
 275                         safe_halt();
 276                 /*
 277                  * TBD: Can't get time duration while in C1, as resumes
 278                  *      go to an ISR rather than here.  Need to instrument
 279                  *      base interrupt handler.
 280                  */
 281                 sleep_ticks = 0xFFFFFFFF;
 282                 break;
 283
 284         case ACPI_STATE_C2:
 285                 /* Get start time (ticks) */
 286                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 287                 /* Invoke C2 */
 288                 inb(cx->address);
 289                 /* Dummy op - must do something useless after P_LVL2 read */
 290                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 291                 /* Get end time (ticks) */
 292                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 293                 /* Re-enable interrupts */
 294                 local_irq_enable();
 295                 /* Compute time (ticks) that we were actually asleep */
 296                 sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 297                 break;
 298
 299         case ACPI_STATE_C3:
 300                 /* Disable bus master arbitration */
 301                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1, ACPI_MTX_DO_NOT_LOCK);
 302                 /* Get start time (ticks) */
 303                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 304                 /* Invoke C3 */
 305                 inb(cx->address);
 306                 /* Dummy op - must do something useless after P_LVL3 read */
 307                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 308                 /* Get end time (ticks) */
 309                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 310                 /* Enable bus master arbitration */
 311                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0, ACPI_MTX_DO_NOT_LOCK);
 312                 /* Re-enable interrupts */
 313                 local_irq_enable();
 314                 /* Compute time (ticks) that we were actually asleep */
 315                 sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 316                 break;
 317
 318         default:
 319                 local_irq_enable();
 320                 return;
 321         }
 322
 323         next_state = pr->power.state;
 324
 325         /*
 326          * Promotion?
 327          * ----------
 328          * Track the number of longs (time asleep is greater than threshold)
 329          * and promote when the count threshold is reached.  Note that bus
 330          * mastering activity may prevent promotions.
 331          * Do not promote above max_cstate.
 332          */
 333         if (cx->promotion.state &&
 334             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 335                 if (sleep_ticks > cx->promotion.threshold.ticks) {
 336                         cx->promotion.count++;
 337                         cx->demotion.count = 0;
 338                         if (cx->promotion.count >= cx->promotion.threshold.count) {
 339                                 if (pr->flags.bm_check) {
 340                                         if (!(pr->power.bm_activity & cx->promotion.threshold.bm)) {
 341                                                 next_state = cx->promotion.state;
 342                                                 goto end;
 343                                         }
 344                                 }
 345                                 else {
 346                                         next_state = cx->promotion.state;
 347                                         goto end;
 348                                 }
 349                         }
 350                 }
 351         }
 352
 353         /*
 354          * Demotion?
 355          * ---------
 356          * Track the number of shorts (time asleep is less than time threshold)
 357          * and demote when the usage threshold is reached.
 358          */
 359         if (cx->demotion.state) {
 360                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 361                         cx->demotion.count++;
 362                         cx->promotion.count = 0;
 363                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 364                                 next_state = cx->demotion.state;
 365                                 goto end;
 366                         }
 367                 }
 368         }
 369
 370 end:
 371         /*
 372          * Demote if current state exceeds max_cstate
 373          */
 374         if ((pr->power.state - pr->power.states) > max_cstate) {
 375                 if (cx->demotion.state)
 376                         next_state = cx->demotion.state;
 377         }
 378
 379         /*
 380          * New Cx State?
 381          * -------------
 382          * If we're going to start using a new Cx state we must clean up
 383          * from the previous and prepare to use the new.
 384          */
 385         if (next_state != pr->power.state)
 386                 acpi_processor_power_activate(pr, next_state);
 387
 388         return;
 389
 390  easy_out:
 391         /* do C1 instead of busy loop */
 392         if (pm_idle_save)
 393                 pm_idle_save();
 394         else
 395                 safe_halt();
 396         return;
 397 }
 398
 399
 400 static int
 401 acpi_processor_set_power_policy (
 402         struct acpi_processor   *pr)
 403 {
 404         unsigned int i;
 405         unsigned int state_is_set = 0;
 406         struct acpi_processor_cx *lower = NULL;
 407         struct acpi_processor_cx *higher = NULL;
 408         struct acpi_processor_cx *cx;
 409
 410         ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
 411
 412         if (!pr)
 413                 return_VALUE(-EINVAL);
 414
 415         /*
 416          * This function sets the default Cx state policy (OS idle handler).
 417          * Our scheme is to promote quickly to C2 but more conservatively
 418          * to C3.  We're favoring C2  for its characteristics of low latency
 419          * (quick response), good power savings, and ability to allow bus
 420          * mastering activity.  Note that the Cx state policy is completely
 421          * customizable and can be altered dynamically.
 422          */
 423
 424         /* startup state */
 425         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 426                 cx = &pr->power.states[i];
 427                 if (!cx->valid)
 428                         continue;
 429
 430                 if (!state_is_set)
 431                         pr->power.state = cx;
 432                 state_is_set++;
 433                 break;
 434         }
 435
 436         if (!state_is_set)
 437                 return_VALUE(-ENODEV);
 438
 439         /* demotion */
 440         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 441                 cx = &pr->power.states[i];
 442                 if (!cx->valid)
 443                         continue;
 444
 445                 if (lower) {
 446                         cx->demotion.state = lower;
 447                         cx->demotion.threshold.ticks = cx->latency_ticks;
 448                         cx->demotion.threshold.count = 1;
 449                         if (cx->type == ACPI_STATE_C3)
 450                                 cx->demotion.threshold.bm = bm_history;
 451                 }
 452
 453                 lower = cx;
 454         }
 455
 456         /* promotion */
 457         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 458                 cx = &pr->power.states[i];
 459                 if (!cx->valid)
 460                         continue;
 461
 462                 if (higher) {
 463                         cx->promotion.state  = higher;
 464                         cx->promotion.threshold.ticks = cx->latency_ticks;
 465                         if (cx->type >= ACPI_STATE_C2)
 466                                 cx->promotion.threshold.count = 4;
 467                         else
 468                                 cx->promotion.threshold.count = 10;
 469                         if (higher->type == ACPI_STATE_C3)
 470                                 cx->promotion.threshold.bm = bm_history;
 471                 }
 472
 473                 higher = cx;
 474         }
 475
 476         return_VALUE(0);
 477 }
 478
 479
 480 static int acpi_processor_get_power_info_fadt (struct acpi_processor *pr)
 481 {
 482         int i;
 483
 484         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
 485
 486         if (!pr)
 487                 return_VALUE(-EINVAL);
 488
 489         if (!pr->pblk)
 490                 return_VALUE(-ENODEV);
 491
 492         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 493                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 494
 495         /* if info is obtained from pblk/fadt, type equals state */
 496         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 497         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 498         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 499
 500         /* the C0 state only exists as a filler in our array,
 501          * and all processors need to support C1 */
 502         pr->power.states[ACPI_STATE_C0].valid = 1;
 503         pr->power.states[ACPI_STATE_C1].valid = 1;
 504
 505         /* determine C2 and C3 address from pblk */
 506         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 507         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 508
 509         /* determine latencies from FADT */
 510         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 511         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 512
 513         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 514                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 515                           pr->power.states[ACPI_STATE_C2].address,
 516                           pr->power.states[ACPI_STATE_C3].address));
 517
 518         return_VALUE(0);
 519 }
 520
 521
 522 static int acpi_processor_get_power_info_cst (struct acpi_processor *pr)
 523 {
 524         acpi_status             status = 0;
 525         acpi_integer            count;
 526         int                     i;
 527         struct acpi_buffer      buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 528         union acpi_object       *cst;
 529
 530         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
 531
 532         if (errata.smp)
 533                 return_VALUE(-ENODEV);
 534
 535         if (nocst)
 536                 return_VALUE(-ENODEV);
 537
 538         pr->power.count = 0;
 539         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 540                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 541
 542         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 543         if (ACPI_FAILURE(status)) {
 544                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 545                 return_VALUE(-ENODEV);
 546         }
 547
 548         cst = (union acpi_object *) buffer.pointer;
 549
 550         /* There must be at least 2 elements */
 551         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 552                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "not enough elements in _CST\n"));
 553                 status = -EFAULT;
 554                 goto end;
 555         }
 556
 557         count = cst->package.elements[0].integer.value;
 558
 559         /* Validate number of power states. */
 560         if (count < 1 || count != cst->package.count - 1) {
 561                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "count given by _CST is not valid\n"));
 562                 status = -EFAULT;
 563                 goto end;
 564         }
 565
 566         /* We support up to ACPI_PROCESSOR_MAX_POWER. */
 567         if (count > ACPI_PROCESSOR_MAX_POWER) {
 568                 printk(KERN_WARNING "Limiting number of power states to max (%d)\n", ACPI_PROCESSOR_MAX_POWER);
 569                 printk(KERN_WARNING "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 570                 count = ACPI_PROCESSOR_MAX_POWER;
 571         }
 572
 573         /* Tell driver that at least _CST is supported. */
 574         pr->flags.has_cst = 1;
 575
 576         for (i = 1; i <= count; i++) {
 577                 union acpi_object *element;
 578                 union acpi_object *obj;
 579                 struct acpi_power_register *reg;
 580                 struct acpi_processor_cx cx;
 581
 582                 memset(&cx, 0, sizeof(cx));
 583
 584                 element = (union acpi_object *) &(cst->package.elements[i]);
 585                 if (element->type != ACPI_TYPE_PACKAGE)
 586                         continue;
 587
 588                 if (element->package.count != 4)
 589                         continue;
 590
 591                 obj = (union acpi_object *) &(element->package.elements[0]);
 592
 593                 if (obj->type != ACPI_TYPE_BUFFER)
 594                         continue;
 595
 596                 reg = (struct acpi_power_register *) obj->buffer.pointer;
 597
 598                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 599                         (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 600                         continue;
 601
 602                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
 603                         0 : reg->address;
 604
 605                 /* There should be an easy way to extract an integer... */
 606                 obj = (union acpi_object *) &(element->package.elements[1]);
 607                 if (obj->type != ACPI_TYPE_INTEGER)
 608                         continue;
 609
 610                 cx.type = obj->integer.value;
 611
 612                 if ((cx.type != ACPI_STATE_C1) &&
 613                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
 614                         continue;
 615
 616                 if ((cx.type < ACPI_STATE_C1) ||
 617                     (cx.type > ACPI_STATE_C3))
 618                         continue;
 619
 620                 obj = (union acpi_object *) &(element->package.elements[2]);
 621                 if (obj->type != ACPI_TYPE_INTEGER)
 622                         continue;
 623
 624                 cx.latency = obj->integer.value;
 625
 626                 obj = (union acpi_object *) &(element->package.elements[3]);
 627                 if (obj->type != ACPI_TYPE_INTEGER)
 628                         continue;
 629
 630                 cx.power = obj->integer.value;
 631
 632                 (pr->power.count)++;
 633                 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
 634         }
 635
 636         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", pr->power.count));
 637
 638         /* Validate number of power states discovered */
 639         if (pr->power.count < 2)
 640                 status = -ENODEV;
 641
 642 end:
 643         acpi_os_free(buffer.pointer);
 644
 645         return_VALUE(status);
 646 }
 647
 648
 649 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 650 {
 651         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
 652
 653         if (!cx->address)
 654                 return_VOID;
 655
 656         /*
 657          * C2 latency must be less than or equal to 100
 658          * microseconds.
 659          */
 660         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 661                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 662                                   "latency too large [%d]\n",
 663                                   cx->latency));
 664                 return_VOID;
 665         }
 666
 667         /* We're (currently) only supporting C2 on UP */
 668         else if (errata.smp) {
 669                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 670                                   "C2 not supported in SMP mode\n"));
 671                 return_VOID;
 672         }
 673
 674         /*
 675          * Otherwise we've met all of our C2 requirements.
 676          * Normalize the C2 latency to expidite policy
 677          */
 678         cx->valid = 1;
 679         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 680
 681         return_VOID;
 682 }
 683
 684
 685 static void acpi_processor_power_verify_c3(
 686         struct acpi_processor *pr,
 687         struct acpi_processor_cx *cx)
 688 {
 689         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
 690
 691         if (!cx->address)
 692                 return_VOID;
 693
 694         /*
 695          * C3 latency must be less than or equal to 1000
 696          * microseconds.
 697          */
 698         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 699                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 700                                   "latency too large [%d]\n",
 701                                   cx->latency));
 702                 return_VOID;
 703         }
 704
 705         /* bus mastering control is necessary */
 706         else if (!pr->flags.bm_control) {
 707                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 708                                   "C3 support requires bus mastering control\n"));
 709                 return_VOID;
 710         }
 711
 712         /* We're (currently) only supporting C2 on UP */
 713         else if (errata.smp) {
 714                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 715                                   "C3 not supported in SMP mode\n"));
 716                 return_VOID;
 717         }
 718
 719         /*
 720          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 721          * DMA transfers are used by any ISA device to avoid livelock.
 722          * Note that we could disable Type-F DMA (as recommended by
 723          * the erratum), but this is known to disrupt certain ISA
 724          * devices thus we take the conservative approach.
 725          */
 726         else if (errata.piix4.fdma) {
 727                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 728                         "C3 not supported on PIIX4 with Type-F DMA\n"));
 729                 return_VOID;
 730         }
 731
 732         /*
 733          * Otherwise we've met all of our C3 requirements.
 734          * Normalize the C3 latency to expidite policy.  Enable
 735          * checking of bus mastering status (bm_check) so we can
 736          * use this in our C3 policy
 737          */
 738         cx->valid = 1;
 739         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 740         pr->flags.bm_check = 1;
 741
 742         return_VOID;
 743 }
 744
 745
 746 static int acpi_processor_power_verify(struct acpi_processor *pr)
 747 {
 748         unsigned int i;
 749         unsigned int working = 0;
 750
 751         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 752                 struct acpi_processor_cx *cx = &pr->power.states[i];
 753
 754                 switch (cx->type) {
 755                 case ACPI_STATE_C1:
 756                         cx->valid = 1;
 757                         break;
 758
 759                 case ACPI_STATE_C2:
 760                         acpi_processor_power_verify_c2(cx);
 761                         break;
 762
 763                 case ACPI_STATE_C3:
 764                         acpi_processor_power_verify_c3(pr, cx);
 765                         break;
 766                 }
 767
 768                 if (cx->valid)
 769                         working++;
 770         }
 771
 772         return (working);
 773 }
 774
 775 static int acpi_processor_get_power_info (
 776         struct acpi_processor   *pr)
 777 {
 778         unsigned int i;
 779         int result;
 780
 781         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
 782
 783         /* NOTE: the idle thread may not be running while calling
 784          * this function */
 785
 786         result = acpi_processor_get_power_info_cst(pr);
 787         if ((result) || (acpi_processor_power_verify(pr) < 2)) {
 788                 result = acpi_processor_get_power_info_fadt(pr);
 789                 if (result)
 790                         return_VALUE(result);
 791
 792                 if (acpi_processor_power_verify(pr) < 2)
 793                         return_VALUE(-ENODEV);
 794         }
 795
 796         /*
 797          * Set Default Policy
 798          * ------------------
 799          * Now that we know which states are supported, set the default
 800          * policy.  Note that this policy can be changed dynamically
 801          * (e.g. encourage deeper sleeps to conserve battery life when
 802          * not on AC).
 803          */
 804         result = acpi_processor_set_power_policy(pr);
 805         if (result)
 806                 return_VALUE(result);
 807
 808         /*
 809          * if one state of type C2 or C3 is available, mark this
 810          * CPU as being "idle manageable"
 811          */
 812         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 813                 if (pr->power.states[i].valid)
 814                         pr->power.count = i;
 815                 if ((pr->power.states[i].valid) &&
 816                     (pr->power.states[i].type >= ACPI_STATE_C2))
 817                         pr->flags.power = 1;
 818         }
 819
 820         return_VALUE(0);
 821 }
 822
 823 int acpi_processor_cst_has_changed (struct acpi_processor *pr)
 824 {
 825         int                     result = 0;
 826
 827         ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
 828
 829         if (!pr)
 830                 return_VALUE(-EINVAL);
 831
 832         if (errata.smp || nocst) {
 833                 return_VALUE(-ENODEV);
 834         }
 835
 836         if (!pr->flags.power_setup_done)
 837                 return_VALUE(-ENODEV);
 838
 839         /* Fall back to the default idle loop */
 840         pm_idle = pm_idle_save;
 841         synchronize_sched();  /* Relies on interrupts forcing exit from idle. */
 842
 843         pr->flags.power = 0;
 844         result = acpi_processor_get_power_info(pr);
 845         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
 846                 pm_idle = acpi_processor_idle;
 847
 848         return_VALUE(result);
 849 }
 850
 851 /* proc interface */
 852
 853 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
 854 {
 855         struct acpi_processor   *pr = (struct acpi_processor *)seq->private;
 856         unsigned int            i;
 857
 858         ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
 859
 860         if (!pr)
 861                 goto end;
 862
 863         seq_printf(seq, "active state:            C%zd\n"
 864                         "max_cstate:              C%d\n"
 865                         "bus master activity:     %08x\n",
 866                         pr->power.state ? pr->power.state - pr->power.states : 0,
 867                         max_cstate,
 868                         (unsigned)pr->power.bm_activity);
 869
 870         seq_puts(seq, "states:\n");
 871
 872         for (i = 1; i <= pr->power.count; i++) {
 873                 seq_printf(seq, "   %cC%d:                  ",
 874                         (&pr->power.states[i] == pr->power.state?'*':' '), i);
 875
 876                 if (!pr->power.states[i].valid) {
 877                         seq_puts(seq, "<not supported>\n");
 878                         continue;
 879                 }
 880
 881                 switch (pr->power.states[i].type) {
 882                 case ACPI_STATE_C1:
 883                         seq_printf(seq, "type[C1] ");
 884                         break;
 885                 case ACPI_STATE_C2:
 886                         seq_printf(seq, "type[C2] ");
 887                         break;
 888                 case ACPI_STATE_C3:
 889                         seq_printf(seq, "type[C3] ");
 890                         break;
 891                 default:
 892                         seq_printf(seq, "type[--] ");
 893                         break;
 894                 }
 895
 896                 if (pr->power.states[i].promotion.state)
 897                         seq_printf(seq, "promotion[C%zd] ",
 898                                 (pr->power.states[i].promotion.state -
 899                                  pr->power.states));
 900                 else
 901                         seq_puts(seq, "promotion[--] ");
 902
 903                 if (pr->power.states[i].demotion.state)
 904                         seq_printf(seq, "demotion[C%zd] ",
 905                                 (pr->power.states[i].demotion.state -
 906                                  pr->power.states));
 907                 else
 908                         seq_puts(seq, "demotion[--] ");
 909
 910                 seq_printf(seq, "latency[%03d] usage[%08d]\n",
 911                         pr->power.states[i].latency,
 912                         pr->power.states[i].usage);
 913         }
 914
 915 end:
 916         return_VALUE(0);
 917 }
 918
 919 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
 920 {
 921         return single_open(file, acpi_processor_power_seq_show,
 922                                                 PDE(inode)->data);
 923 }
 924
 925 static struct file_operations acpi_processor_power_fops = {
 926         .open           = acpi_processor_power_open_fs,
 927         .read           = seq_read,
 928         .llseek         = seq_lseek,
 929         .release        = single_release,
 930 };
 931
 932
 933 int acpi_processor_power_init(struct acpi_processor *pr, struct acpi_device *device)
 934 {
 935         acpi_status             status = 0;
 936         static int              first_run = 0;
 937         struct proc_dir_entry   *entry = NULL;
 938         unsigned int i;
 939
 940         ACPI_FUNCTION_TRACE("acpi_processor_power_init");
 941
 942         if (!first_run) {
 943                 dmi_check_system(processor_power_dmi_table);
 944                 if (max_cstate < ACPI_C_STATES_MAX)
 945                         printk(KERN_NOTICE "ACPI: processor limited to max C-state %d\n", max_cstate);
 946                 first_run++;
 947         }
 948
 949         if (!errata.smp && (pr->id == 0) && acpi_fadt.cst_cnt && !nocst) {
 950                 status = acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
 951                 if (ACPI_FAILURE(status)) {
 952                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 953                                           "Notifying BIOS of _CST ability failed\n"));
 954                 }
 955         }
 956
 957         acpi_processor_get_power_info(pr);
 958
 959         /*
 960          * Install the idle handler if processor power management is supported.
 961          * Note that we use previously set idle handler will be used on
 962          * platforms that only support C1.
 963          */
 964         if ((pr->flags.power) && (!boot_option_idle_override)) {
 965                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
 966                 for (i = 1; i <= pr->power.count; i++)
 967                         if (pr->power.states[i].valid)
 968                                 printk(" C%d[C%d]", i, pr->power.states[i].type);
 969                 printk(")\n");
 970
 971                 if (pr->id == 0) {
 972                         pm_idle_save = pm_idle;
 973                         pm_idle = acpi_processor_idle;
 974                 }
 975         }
 976
 977         /* 'power' [R] */
 978         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
 979                 S_IRUGO, acpi_device_dir(device));
 980         if (!entry)
 981                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 982                         "Unable to create '%s' fs entry\n",
 983                         ACPI_PROCESSOR_FILE_POWER));
 984         else {
 985                 entry->proc_fops = &acpi_processor_power_fops;
 986                 entry->data = acpi_driver_data(device);
 987                 entry->owner = THIS_MODULE;
 988         }
 989
 990         pr->flags.power_setup_done = 1;
 991
 992         return_VALUE(0);
 993 }
 994
 995 int acpi_processor_power_exit(struct acpi_processor *pr, struct acpi_device *device)
 996 {
 997         ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
 998
 999         pr->flags.power_setup_done = 0;
1000
1001         if (acpi_device_dir(device))
1002                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,acpi_device_dir(device));
1003
1004         /* Unregister the idle handler when processor #0 is removed. */
1005         if (pr->id == 0) {
1006                 pm_idle = pm_idle_save;
1007
1008                 /*
1009                  * We are about to unload the current idle thread pm callback
1010                  * (pm_idle), Wait for all processors to update cached/local
1011                  * copies of pm_idle before proceeding.
1012                  */
1013                 cpu_idle_wait();
1014         }
1015
1016         return_VALUE(0);
1017 }