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  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *                      - Added support for C3 on SMP
  11  *
  12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or (at
  17  *  your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful, but
  20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  *  General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License along
  25  *  with this program; if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  27  *
  28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/cpufreq.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/moduleparam.h>
  40
  41 #include <asm/io.h>
  42 #include <asm/uaccess.h>
  43
  44 #include <acpi/acpi_bus.h>
  45 #include <acpi/processor.h>
  46
  47 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  48 #define ACPI_PROCESSOR_CLASS            "processor"
  49 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
  50 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  51 ACPI_MODULE_NAME                ("acpi_processor")
  52
  53 #define ACPI_PROCESSOR_FILE_POWER       "power"
  54
  55 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  56 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  57 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  58
  59 static void (*pm_idle_save)(void);
  60 module_param(max_cstate, uint, 0644);
  61
  62 static unsigned int nocst = 0;
  63 module_param(nocst, uint, 0000);
  64
  65 /*
  66  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  67  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  68  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  69  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  70  * reduce history for more aggressive entry into C3
  71  */
  72 static unsigned int bm_history = (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  73 module_param(bm_history, uint, 0644);
  74 /* --------------------------------------------------------------------------
  75                                 Power Management
  76    -------------------------------------------------------------------------- */
  77
  78 /*
  79  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  80  * For now disable this. Probably a bug somewhere else.
  81  *
  82  * To skip this limit, boot/load with a large max_cstate limit.
  83  */
  84 static int no_c2c3(struct dmi_system_id *id)
  85 {
  86         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  87                 return 0;
  88
  89         printk(KERN_NOTICE PREFIX "%s detected - C2,C3 disabled."
  90                 " Override with \"processor.max_cstate=%d\"\n", id->ident,
  91                ACPI_PROCESSOR_MAX_POWER + 1);
  92
  93         max_cstate = 1;
  94
  95         return 0;
  96 }
  97
  98
  99
 100
 101 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
 102         { no_c2c3, "IBM ThinkPad R40e", {
 103           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 104           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }},
 105         { no_c2c3, "Medion 41700", {
 106           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 107           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J") }},
 108         {},
 109 };
 110
 111
 112 static inline u32
 113 ticks_elapsed (
 114         u32                     t1,
 115         u32                     t2)
 116 {
 117         if (t2 >= t1)
 118                 return (t2 - t1);
 119         else if (!acpi_fadt.tmr_val_ext)
 120                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 121         else
 122                 return ((0xFFFFFFFF - t1) + t2);
 123 }
 124
 125
 126 static void
 127 acpi_processor_power_activate (
 128         struct acpi_processor   *pr,
 129         struct acpi_processor_cx  *new)
 130 {
 131         struct acpi_processor_cx  *old;
 132
 133         if (!pr || !new)
 134                 return;
 135
 136         old = pr->power.state;
 137
 138         if (old)
 139                 old->promotion.count = 0;
 140         new->demotion.count = 0;
 141
 142         /* Cleanup from old state. */
 143         if (old) {
 144                 switch (old->type) {
 145                 case ACPI_STATE_C3:
 146                         /* Disable bus master reload */
 147                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 148                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0, ACPI_MTX_DO_NOT_LOCK);
 149                         break;
 150                 }
 151         }
 152
 153         /* Prepare to use new state. */
 154         switch (new->type) {
 155         case ACPI_STATE_C3:
 156                 /* Enable bus master reload */
 157                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 158                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1, ACPI_MTX_DO_NOT_LOCK);
 159                 break;
 160         }
 161
 162         pr->power.state = new;
 163
 164         return;
 165 }
 166
 167
 168 static atomic_t         c3_cpu_count;
 169
 170
 171 static void acpi_processor_idle (void)
 172 {
 173         struct acpi_processor   *pr = NULL;
 174         struct acpi_processor_cx *cx = NULL;
 175         struct acpi_processor_cx *next_state = NULL;
 176         int                     sleep_ticks = 0;
 177         u32                     t1, t2 = 0;
 178
 179         pr = processors[raw_smp_processor_id()];
 180         if (!pr)
 181                 return;
 182
 183         /*
 184          * Interrupts must be disabled during bus mastering calculations and
 185          * for C2/C3 transitions.
 186          */
 187         local_irq_disable();
 188
 189         /*
 190          * Check whether we truly need to go idle, or should
 191          * reschedule:
 192          */
 193         if (unlikely(need_resched())) {
 194                 local_irq_enable();
 195                 return;
 196         }
 197
 198         cx = pr->power.state;
 199         if (!cx)
 200                 goto easy_out;
 201
 202         /*
 203          * Check BM Activity
 204          * -----------------
 205          * Check for bus mastering activity (if required), record, and check
 206          * for demotion.
 207          */
 208         if (pr->flags.bm_check) {
 209                 u32             bm_status = 0;
 210                 unsigned long   diff = jiffies - pr->power.bm_check_timestamp;
 211
 212                 if (diff > 32)
 213                         diff = 32;
 214
 215                 while (diff) {
 216                         /* if we didn't get called, assume there was busmaster activity */
 217                         diff--;
 218                         if (diff)
 219                                 pr->power.bm_activity |= 0x1;
 220                         pr->power.bm_activity <<= 1;
 221                 }
 222
 223                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 224                         &bm_status, ACPI_MTX_DO_NOT_LOCK);
 225                 if (bm_status) {
 226                         pr->power.bm_activity++;
 227                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 228                                 1, ACPI_MTX_DO_NOT_LOCK);
 229                 }
 230                 /*
 231                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 232                  * the true state of bus mastering activity; forcing us to
 233                  * manually check the BMIDEA bit of each IDE channel.
 234                  */
 235                 else if (errata.piix4.bmisx) {
 236                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 237                                 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 238                                 pr->power.bm_activity++;
 239                 }
 240
 241                 pr->power.bm_check_timestamp = jiffies;
 242
 243                 /*
 244                  * Apply bus mastering demotion policy.  Automatically demote
 245                  * to avoid a faulty transition.  Note that the processor
 246                  * won't enter a low-power state during this call (to this
 247                  * funciton) but should upon the next.
 248                  *
 249                  * TBD: A better policy might be to fallback to the demotion
 250                  *      state (use it for this quantum only) istead of
 251                  *      demoting -- and rely on duration as our sole demotion
 252                  *      qualification.  This may, however, introduce DMA
 253                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 254                  */
 255                 if (pr->power.bm_activity & cx->demotion.threshold.bm) {
 256                         local_irq_enable();
 257                         next_state = cx->demotion.state;
 258                         goto end;
 259                 }
 260         }
 261
 262         cx->usage++;
 263
 264         /*
 265          * Sleep:
 266          * ------
 267          * Invoke the current Cx state to put the processor to sleep.
 268          */
 269         switch (cx->type) {
 270
 271         case ACPI_STATE_C1:
 272                 /*
 273                  * Invoke C1.
 274                  * Use the appropriate idle routine, the one that would
 275                  * be used without acpi C-states.
 276                  */
 277                 if (pm_idle_save)
 278                         pm_idle_save();
 279                 else
 280                         safe_halt();
 281                 /*
 282                  * TBD: Can't get time duration while in C1, as resumes
 283                  *      go to an ISR rather than here.  Need to instrument
 284                  *      base interrupt handler.
 285                  */
 286                 sleep_ticks = 0xFFFFFFFF;
 287                 break;
 288
 289         case ACPI_STATE_C2:
 290                 /* Get start time (ticks) */
 291                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 292                 /* Invoke C2 */
 293                 inb(cx->address);
 294                 /* Dummy op - must do something useless after P_LVL2 read */
 295                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 296                 /* Get end time (ticks) */
 297                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 298                 /* Re-enable interrupts */
 299                 local_irq_enable();
 300                 /* Compute time (ticks) that we were actually asleep */
 301                 sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 302                 break;
 303
 304         case ACPI_STATE_C3:
 305
 306                 if (pr->flags.bm_check) {
 307                         if (atomic_inc_return(&c3_cpu_count) ==
 308                                         num_online_cpus()) {
 309                                 /*
 310                                  * All CPUs are trying to go to C3
 311                                  * Disable bus master arbitration
 312                                  */
 313                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
 314                                         ACPI_MTX_DO_NOT_LOCK);
 315                         }
 316                 } else {
 317                         /* SMP with no shared cache... Invalidate cache  */
 318                         ACPI_FLUSH_CPU_CACHE();
 319                 }
 320
 321                 /* Get start time (ticks) */
 322                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 323                 /* Invoke C3 */
 324                 inb(cx->address);
 325                 /* Dummy op - must do something useless after P_LVL3 read */
 326                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 327                 /* Get end time (ticks) */
 328                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 329                 if (pr->flags.bm_check) {
 330                         /* Enable bus master arbitration */
 331                         atomic_dec(&c3_cpu_count);
 332                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0, ACPI_MTX_DO_NOT_LOCK);
 333                 }
 334
 335                 /* Re-enable interrupts */
 336                 local_irq_enable();
 337                 /* Compute time (ticks) that we were actually asleep */
 338                 sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 339                 break;
 340
 341         default:
 342                 local_irq_enable();
 343                 return;
 344         }
 345
 346         next_state = pr->power.state;
 347
 348         /*
 349          * Promotion?
 350          * ----------
 351          * Track the number of longs (time asleep is greater than threshold)
 352          * and promote when the count threshold is reached.  Note that bus
 353          * mastering activity may prevent promotions.
 354          * Do not promote above max_cstate.
 355          */
 356         if (cx->promotion.state &&
 357             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 358                 if (sleep_ticks > cx->promotion.threshold.ticks) {
 359                         cx->promotion.count++;
 360                         cx->demotion.count = 0;
 361                         if (cx->promotion.count >= cx->promotion.threshold.count) {
 362                                 if (pr->flags.bm_check) {
 363                                         if (!(pr->power.bm_activity & cx->promotion.threshold.bm)) {
 364                                                 next_state = cx->promotion.state;
 365                                                 goto end;
 366                                         }
 367                                 }
 368                                 else {
 369                                         next_state = cx->promotion.state;
 370                                         goto end;
 371                                 }
 372                         }
 373                 }
 374         }
 375
 376         /*
 377          * Demotion?
 378          * ---------
 379          * Track the number of shorts (time asleep is less than time threshold)
 380          * and demote when the usage threshold is reached.
 381          */
 382         if (cx->demotion.state) {
 383                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 384                         cx->demotion.count++;
 385                         cx->promotion.count = 0;
 386                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 387                                 next_state = cx->demotion.state;
 388                                 goto end;
 389                         }
 390                 }
 391         }
 392
 393 end:
 394         /*
 395          * Demote if current state exceeds max_cstate
 396          */
 397         if ((pr->power.state - pr->power.states) > max_cstate) {
 398                 if (cx->demotion.state)
 399                         next_state = cx->demotion.state;
 400         }
 401
 402         /*
 403          * New Cx State?
 404          * -------------
 405          * If we're going to start using a new Cx state we must clean up
 406          * from the previous and prepare to use the new.
 407          */
 408         if (next_state != pr->power.state)
 409                 acpi_processor_power_activate(pr, next_state);
 410
 411         return;
 412
 413  easy_out:
 414         /* do C1 instead of busy loop */
 415         if (pm_idle_save)
 416                 pm_idle_save();
 417         else
 418                 safe_halt();
 419         return;
 420 }
 421
 422
 423 static int
 424 acpi_processor_set_power_policy (
 425         struct acpi_processor   *pr)
 426 {
 427         unsigned int i;
 428         unsigned int state_is_set = 0;
 429         struct acpi_processor_cx *lower = NULL;
 430         struct acpi_processor_cx *higher = NULL;
 431         struct acpi_processor_cx *cx;
 432
 433         ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
 434
 435         if (!pr)
 436                 return_VALUE(-EINVAL);
 437
 438         /*
 439          * This function sets the default Cx state policy (OS idle handler).
 440          * Our scheme is to promote quickly to C2 but more conservatively
 441          * to C3.  We're favoring C2  for its characteristics of low latency
 442          * (quick response), good power savings, and ability to allow bus
 443          * mastering activity.  Note that the Cx state policy is completely
 444          * customizable and can be altered dynamically.
 445          */
 446
 447         /* startup state */
 448         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 449                 cx = &pr->power.states[i];
 450                 if (!cx->valid)
 451                         continue;
 452
 453                 if (!state_is_set)
 454                         pr->power.state = cx;
 455                 state_is_set++;
 456                 break;
 457         }
 458
 459         if (!state_is_set)
 460                 return_VALUE(-ENODEV);
 461
 462         /* demotion */
 463         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 464                 cx = &pr->power.states[i];
 465                 if (!cx->valid)
 466                         continue;
 467
 468                 if (lower) {
 469                         cx->demotion.state = lower;
 470                         cx->demotion.threshold.ticks = cx->latency_ticks;
 471                         cx->demotion.threshold.count = 1;
 472                         if (cx->type == ACPI_STATE_C3)
 473                                 cx->demotion.threshold.bm = bm_history;
 474                 }
 475
 476                 lower = cx;
 477         }
 478
 479         /* promotion */
 480         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 481                 cx = &pr->power.states[i];
 482                 if (!cx->valid)
 483                         continue;
 484
 485                 if (higher) {
 486                         cx->promotion.state  = higher;
 487                         cx->promotion.threshold.ticks = cx->latency_ticks;
 488                         if (cx->type >= ACPI_STATE_C2)
 489                                 cx->promotion.threshold.count = 4;
 490                         else
 491                                 cx->promotion.threshold.count = 10;
 492                         if (higher->type == ACPI_STATE_C3)
 493                                 cx->promotion.threshold.bm = bm_history;
 494                 }
 495
 496                 higher = cx;
 497         }
 498
 499         return_VALUE(0);
 500 }
 501
 502
 503 static int acpi_processor_get_power_info_fadt (struct acpi_processor *pr)
 504 {
 505         int i;
 506
 507         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
 508
 509         if (!pr)
 510                 return_VALUE(-EINVAL);
 511
 512         if (!pr->pblk)
 513                 return_VALUE(-ENODEV);
 514
 515         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 516                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 517
 518         /* if info is obtained from pblk/fadt, type equals state */
 519         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 520         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 521         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 522
 523         /* the C0 state only exists as a filler in our array,
 524          * and all processors need to support C1 */
 525         pr->power.states[ACPI_STATE_C0].valid = 1;
 526         pr->power.states[ACPI_STATE_C1].valid = 1;
 527
 528         /* determine C2 and C3 address from pblk */
 529         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 530         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 531
 532         /* determine latencies from FADT */
 533         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 534         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 535
 536         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 537                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 538                           pr->power.states[ACPI_STATE_C2].address,
 539                           pr->power.states[ACPI_STATE_C3].address));
 540
 541         return_VALUE(0);
 542 }
 543
 544
 545 static int acpi_processor_get_power_info_default_c1 (struct acpi_processor *pr)
 546 {
 547         int i;
 548
 549         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
 550
 551         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 552                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 553
 554         /* if info is obtained from pblk/fadt, type equals state */
 555         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 556         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 557         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 558
 559         /* the C0 state only exists as a filler in our array,
 560          * and all processors need to support C1 */
 561         pr->power.states[ACPI_STATE_C0].valid = 1;
 562         pr->power.states[ACPI_STATE_C1].valid = 1;
 563
 564         return_VALUE(0);
 565 }
 566
 567
 568 static int acpi_processor_get_power_info_cst (struct acpi_processor *pr)
 569 {
 570         acpi_status             status = 0;
 571         acpi_integer            count;
 572         int                     i;
 573         struct acpi_buffer      buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 574         union acpi_object       *cst;
 575
 576         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
 577
 578         if (nocst)
 579                 return_VALUE(-ENODEV);
 580
 581         pr->power.count = 0;
 582         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 583                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 584
 585         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 586         if (ACPI_FAILURE(status)) {
 587                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 588                 return_VALUE(-ENODEV);
 589         }
 590
 591         cst = (union acpi_object *) buffer.pointer;
 592
 593         /* There must be at least 2 elements */
 594         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 595                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "not enough elements in _CST\n"));
 596                 status = -EFAULT;
 597                 goto end;
 598         }
 599
 600         count = cst->package.elements[0].integer.value;
 601
 602         /* Validate number of power states. */
 603         if (count < 1 || count != cst->package.count - 1) {
 604                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "count given by _CST is not valid\n"));
 605                 status = -EFAULT;
 606                 goto end;
 607         }
 608
 609         /* We support up to ACPI_PROCESSOR_MAX_POWER. */
 610         if (count > ACPI_PROCESSOR_MAX_POWER) {
 611                 printk(KERN_WARNING "Limiting number of power states to max (%d)\n", ACPI_PROCESSOR_MAX_POWER);
 612                 printk(KERN_WARNING "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 613                 count = ACPI_PROCESSOR_MAX_POWER;
 614         }
 615
 616         /* Tell driver that at least _CST is supported. */
 617         pr->flags.has_cst = 1;
 618
 619         for (i = 1; i <= count; i++) {
 620                 union acpi_object *element;
 621                 union acpi_object *obj;
 622                 struct acpi_power_register *reg;
 623                 struct acpi_processor_cx cx;
 624
 625                 memset(&cx, 0, sizeof(cx));
 626
 627                 element = (union acpi_object *) &(cst->package.elements[i]);
 628                 if (element->type != ACPI_TYPE_PACKAGE)
 629                         continue;
 630
 631                 if (element->package.count != 4)
 632                         continue;
 633
 634                 obj = (union acpi_object *) &(element->package.elements[0]);
 635
 636                 if (obj->type != ACPI_TYPE_BUFFER)
 637                         continue;
 638
 639                 reg = (struct acpi_power_register *) obj->buffer.pointer;
 640
 641                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 642                         (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 643                         continue;
 644
 645                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
 646                         0 : reg->address;
 647
 648                 /* There should be an easy way to extract an integer... */
 649                 obj = (union acpi_object *) &(element->package.elements[1]);
 650                 if (obj->type != ACPI_TYPE_INTEGER)
 651                         continue;
 652
 653                 cx.type = obj->integer.value;
 654
 655                 if ((cx.type != ACPI_STATE_C1) &&
 656                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
 657                         continue;
 658
 659                 if ((cx.type < ACPI_STATE_C1) ||
 660                     (cx.type > ACPI_STATE_C3))
 661                         continue;
 662
 663                 obj = (union acpi_object *) &(element->package.elements[2]);
 664                 if (obj->type != ACPI_TYPE_INTEGER)
 665                         continue;
 666
 667                 cx.latency = obj->integer.value;
 668
 669                 obj = (union acpi_object *) &(element->package.elements[3]);
 670                 if (obj->type != ACPI_TYPE_INTEGER)
 671                         continue;
 672
 673                 cx.power = obj->integer.value;
 674
 675                 (pr->power.count)++;
 676                 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
 677         }
 678
 679         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", pr->power.count));
 680
 681         /* Validate number of power states discovered */
 682         if (pr->power.count < 2)
 683                 status = -ENODEV;
 684
 685 end:
 686         acpi_os_free(buffer.pointer);
 687
 688         return_VALUE(status);
 689 }
 690
 691
 692 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 693 {
 694         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
 695
 696         if (!cx->address)
 697                 return_VOID;
 698
 699         /*
 700          * C2 latency must be less than or equal to 100
 701          * microseconds.
 702          */
 703         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 704                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 705                                   "latency too large [%d]\n",
 706                                   cx->latency));
 707                 return_VOID;
 708         }
 709
 710         /*
 711          * Otherwise we've met all of our C2 requirements.
 712          * Normalize the C2 latency to expidite policy
 713          */
 714         cx->valid = 1;
 715         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 716
 717         return_VOID;
 718 }
 719
 720
 721 static void acpi_processor_power_verify_c3(
 722         struct acpi_processor *pr,
 723         struct acpi_processor_cx *cx)
 724 {
 725         static int bm_check_flag;
 726
 727         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
 728
 729         if (!cx->address)
 730                 return_VOID;
 731
 732         /*
 733          * C3 latency must be less than or equal to 1000
 734          * microseconds.
 735          */
 736         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 737                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 738                                   "latency too large [%d]\n",
 739                                   cx->latency));
 740                 return_VOID;
 741         }
 742
 743         /*
 744          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 745          * DMA transfers are used by any ISA device to avoid livelock.
 746          * Note that we could disable Type-F DMA (as recommended by
 747          * the erratum), but this is known to disrupt certain ISA
 748          * devices thus we take the conservative approach.
 749          */
 750         else if (errata.piix4.fdma) {
 751                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 752                         "C3 not supported on PIIX4 with Type-F DMA\n"));
 753                 return_VOID;
 754         }
 755
 756         /* All the logic here assumes flags.bm_check is same across all CPUs */
 757         if (!bm_check_flag) {
 758                 /* Determine whether bm_check is needed based on CPU  */
 759                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 760                 bm_check_flag = pr->flags.bm_check;
 761         } else {
 762                 pr->flags.bm_check = bm_check_flag;
 763         }
 764
 765         if (pr->flags.bm_check) {
 766                 printk("Disabling BM access before entering C3\n");
 767                 /* bus mastering control is necessary */
 768                 if (!pr->flags.bm_control) {
 769                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 770                           "C3 support requires bus mastering control\n"));
 771                         return_VOID;
 772                 }
 773         } else {
 774                 printk("Invalidating cache before entering C3\n");
 775                 /*
 776                  * WBINVD should be set in fadt, for C3 state to be
 777                  * supported on when bm_check is not required.
 778                  */
 779                 if (acpi_fadt.wb_invd != 1) {
 780                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 781                           "Cache invalidation should work properly"
 782                           " for C3 to be enabled on SMP systems\n"));
 783                         return_VOID;
 784                 }
 785                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
 786                                 0, ACPI_MTX_DO_NOT_LOCK);
 787         }
 788
 789         /*
 790          * Otherwise we've met all of our C3 requirements.
 791          * Normalize the C3 latency to expidite policy.  Enable
 792          * checking of bus mastering status (bm_check) so we can
 793          * use this in our C3 policy
 794          */
 795         cx->valid = 1;
 796         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 797
 798         return_VOID;
 799 }
 800
 801
 802 static int acpi_processor_power_verify(struct acpi_processor *pr)
 803 {
 804         unsigned int i;
 805         unsigned int working = 0;
 806
 807         for (i=1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 808                 struct acpi_processor_cx *cx = &pr->power.states[i];
 809
 810                 switch (cx->type) {
 811                 case ACPI_STATE_C1:
 812                         cx->valid = 1;
 813                         break;
 814
 815                 case ACPI_STATE_C2:
 816                         acpi_processor_power_verify_c2(cx);
 817                         break;
 818
 819                 case ACPI_STATE_C3:
 820                         acpi_processor_power_verify_c3(pr, cx);
 821                         break;
 822                 }
 823
 824                 if (cx->valid)
 825                         working++;
 826         }
 827
 828         return (working);
 829 }
 830
 831 static int acpi_processor_get_power_info (
 832         struct acpi_processor   *pr)
 833 {
 834         unsigned int i;
 835         int result;
 836
 837         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
 838
 839         /* NOTE: the idle thread may not be running while calling
 840          * this function */
 841
 842         result = acpi_processor_get_power_info_cst(pr);
 843         if ((result) || (acpi_processor_power_verify(pr) < 2)) {
 844                 result = acpi_processor_get_power_info_fadt(pr);
 845                 if (result)
 846                         result = acpi_processor_get_power_info_default_c1(pr);
 847         }
 848
 849         /*
 850          * Set Default Policy
 851          * ------------------
 852          * Now that we know which states are supported, set the default
 853          * policy.  Note that this policy can be changed dynamically
 854          * (e.g. encourage deeper sleeps to conserve battery life when
 855          * not on AC).
 856          */
 857         result = acpi_processor_set_power_policy(pr);
 858         if (result)
 859                 return_VALUE(result);
 860
 861         /*
 862          * if one state of type C2 or C3 is available, mark this
 863          * CPU as being "idle manageable"
 864          */
 865         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 866                 if (pr->power.states[i].valid) {
 867                         pr->power.count = i;
 868                         pr->flags.power = 1;
 869                 }
 870         }
 871
 872         return_VALUE(0);
 873 }
 874
 875 int acpi_processor_cst_has_changed (struct acpi_processor *pr)
 876 {
 877         int                     result = 0;
 878
 879         ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
 880
 881         if (!pr)
 882                 return_VALUE(-EINVAL);
 883
 884         if ( nocst) {
 885                 return_VALUE(-ENODEV);
 886         }
 887
 888         if (!pr->flags.power_setup_done)
 889                 return_VALUE(-ENODEV);
 890
 891         /* Fall back to the default idle loop */
 892         pm_idle = pm_idle_save;
 893         synchronize_sched();  /* Relies on interrupts forcing exit from idle. */
 894
 895         pr->flags.power = 0;
 896         result = acpi_processor_get_power_info(pr);
 897         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
 898                 pm_idle = acpi_processor_idle;
 899
 900         return_VALUE(result);
 901 }
 902
 903 /* proc interface */
 904
 905 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
 906 {
 907         struct acpi_processor   *pr = (struct acpi_processor *)seq->private;
 908         unsigned int            i;
 909
 910         ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
 911
 912         if (!pr)
 913                 goto end;
 914
 915         seq_printf(seq, "active state:            C%zd\n"
 916                         "max_cstate:              C%d\n"
 917                         "bus master activity:     %08x\n",
 918                         pr->power.state ? pr->power.state - pr->power.states : 0,
 919                         max_cstate,
 920                         (unsigned)pr->power.bm_activity);
 921
 922         seq_puts(seq, "states:\n");
 923
 924         for (i = 1; i <= pr->power.count; i++) {
 925                 seq_printf(seq, "   %cC%d:                  ",
 926                         (&pr->power.states[i] == pr->power.state?'*':' '), i);
 927
 928                 if (!pr->power.states[i].valid) {
 929                         seq_puts(seq, "<not supported>\n");
 930                         continue;
 931                 }
 932
 933                 switch (pr->power.states[i].type) {
 934                 case ACPI_STATE_C1:
 935                         seq_printf(seq, "type[C1] ");
 936                         break;
 937                 case ACPI_STATE_C2:
 938                         seq_printf(seq, "type[C2] ");
 939                         break;
 940                 case ACPI_STATE_C3:
 941                         seq_printf(seq, "type[C3] ");
 942                         break;
 943                 default:
 944                         seq_printf(seq, "type[--] ");
 945                         break;
 946                 }
 947
 948                 if (pr->power.states[i].promotion.state)
 949                         seq_printf(seq, "promotion[C%zd] ",
 950                                 (pr->power.states[i].promotion.state -
 951                                  pr->power.states));
 952                 else
 953                         seq_puts(seq, "promotion[--] ");
 954
 955                 if (pr->power.states[i].demotion.state)
 956                         seq_printf(seq, "demotion[C%zd] ",
 957                                 (pr->power.states[i].demotion.state -
 958                                  pr->power.states));
 959                 else
 960                         seq_puts(seq, "demotion[--] ");
 961
 962                 seq_printf(seq, "latency[%03d] usage[%08d]\n",
 963                         pr->power.states[i].latency,
 964                         pr->power.states[i].usage);
 965         }
 966
 967 end:
 968         return_VALUE(0);
 969 }
 970
 971 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
 972 {
 973         return single_open(file, acpi_processor_power_seq_show,
 974                                                 PDE(inode)->data);
 975 }
 976
 977 static struct file_operations acpi_processor_power_fops = {
 978         .open           = acpi_processor_power_open_fs,
 979         .read           = seq_read,
 980         .llseek         = seq_lseek,
 981         .release        = single_release,
 982 };
 983
 984 int acpi_processor_power_init(struct acpi_processor *pr, struct acpi_device *device)
 985 {
 986         acpi_status             status = 0;
 987         static int              first_run = 0;
 988         struct proc_dir_entry   *entry = NULL;
 989         unsigned int i;
 990
 991         ACPI_FUNCTION_TRACE("acpi_processor_power_init");
 992
 993         if (!first_run) {
 994                 dmi_check_system(processor_power_dmi_table);
 995                 if (max_cstate < ACPI_C_STATES_MAX)
 996                         printk(KERN_NOTICE "ACPI: processor limited to max C-state %d\n", max_cstate);
 997                 first_run++;
 998         }
 999
1000         if (!pr)
1001                 return_VALUE(-EINVAL);
1002
1003         if (acpi_fadt.cst_cnt && !nocst) {
1004                 status = acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1005                 if (ACPI_FAILURE(status)) {
1006                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1007                                           "Notifying BIOS of _CST ability failed\n"));
1008                 }
1009         }
1010
1011         acpi_processor_power_init_pdc(&(pr->power), pr->id);
1012         acpi_processor_set_pdc(pr, pr->power.pdc);
1013         acpi_processor_get_power_info(pr);
1014
1015         /*
1016          * Install the idle handler if processor power management is supported.
1017          * Note that we use previously set idle handler will be used on
1018          * platforms that only support C1.
1019          */
1020         if ((pr->flags.power) && (!boot_option_idle_override)) {
1021                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1022                 for (i = 1; i <= pr->power.count; i++)
1023                         if (pr->power.states[i].valid)
1024                                 printk(" C%d[C%d]", i, pr->power.states[i].type);
1025                 printk(")\n");
1026
1027                 if (pr->id == 0) {
1028                         pm_idle_save = pm_idle;
1029                         pm_idle = acpi_processor_idle;
1030                 }
1031         }
1032
1033         /* 'power' [R] */
1034         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1035                 S_IRUGO, acpi_device_dir(device));
1036         if (!entry)
1037                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1038                         "Unable to create '%s' fs entry\n",
1039                         ACPI_PROCESSOR_FILE_POWER));
1040         else {
1041                 entry->proc_fops = &acpi_processor_power_fops;
1042                 entry->data = acpi_driver_data(device);
1043                 entry->owner = THIS_MODULE;
1044         }
1045
1046         pr->flags.power_setup_done = 1;
1047
1048         return_VALUE(0);
1049 }
1050
1051 int acpi_processor_power_exit(struct acpi_processor *pr, struct acpi_device *device)
1052 {
1053         ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
1054
1055         pr->flags.power_setup_done = 0;
1056
1057         if (acpi_device_dir(device))
1058                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,acpi_device_dir(device));
1059
1060         /* Unregister the idle handler when processor #0 is removed. */
1061         if (pr->id == 0) {
1062                 pm_idle = pm_idle_save;
1063
1064                 /*
1065                  * We are about to unload the current idle thread pm callback
1066                  * (pm_idle), Wait for all processors to update cached/local
1067                  * copies of pm_idle before proceeding.
1068                  */
1069                 cpu_idle_wait();
1070         }
1071
1072         return_VALUE(0);
1073 }