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 #define ACPI_PROCESSOR_FILE_POWER       "power"
  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 static void (*pm_idle_save) (void);
  57 module_param(max_cstate, uint, 0644);
  58
  59 static unsigned int nocst = 0;
  60 module_param(nocst, uint, 0000);
  61
  62 /*
  63  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  64  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  65  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  66  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  67  * reduce history for more aggressive entry into C3
  68  */
  69 static unsigned int bm_history =
  70     (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 set_max_cstate(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 - limiting to C%ld max_cstate."
  88                " Override with \"processor.max_cstate=%d\"\n", id->ident,
  89                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  90
  91         max_cstate = (long)id->driver_data;
  92
  93         return 0;
  94 }
  95
  96 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
  97         {set_max_cstate, "IBM ThinkPad R40e", {
  98                                                DMI_MATCH(DMI_BIOS_VENDOR,
  99                                                          "IBM"),
 100                                                DMI_MATCH(DMI_BIOS_VERSION,
 101                                                          "1SET60WW")},
 102          (void *)1},
 103         {set_max_cstate, "Medion 41700", {
 104                                           DMI_MATCH(DMI_BIOS_VENDOR,
 105                                                     "Phoenix Technologies LTD"),
 106                                           DMI_MATCH(DMI_BIOS_VERSION,
 107                                                     "R01-A1J")}, (void *)1},
 108         {set_max_cstate, "Clevo 5600D", {
 109                                          DMI_MATCH(DMI_BIOS_VENDOR,
 110                                                    "Phoenix Technologies LTD"),
 111                                          DMI_MATCH(DMI_BIOS_VERSION,
 112                                                    "SHE845M0.86C.0013.D.0302131307")},
 113          (void *)2},
 114         {},
 115 };
 116
 117 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 118 {
 119         if (t2 >= t1)
 120                 return (t2 - t1);
 121         else if (!acpi_fadt.tmr_val_ext)
 122                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 123         else
 124                 return ((0xFFFFFFFF - t1) + t2);
 125 }
 126
 127 static void
 128 acpi_processor_power_activate(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,
 149                                                   ACPI_MTX_DO_NOT_LOCK);
 150                         break;
 151                 }
 152         }
 153
 154         /* Prepare to use new state. */
 155         switch (new->type) {
 156         case ACPI_STATE_C3:
 157                 /* Enable bus master reload */
 158                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 159                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
 160                                           ACPI_MTX_DO_NOT_LOCK);
 161                 break;
 162         }
 163
 164         pr->power.state = new;
 165
 166         return;
 167 }
 168
 169 static atomic_t c3_cpu_count;
 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 =
 302                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 303                 break;
 304
 305         case ACPI_STATE_C3:
 306
 307                 if (pr->flags.bm_check) {
 308                         if (atomic_inc_return(&c3_cpu_count) ==
 309                             num_online_cpus()) {
 310                                 /*
 311                                  * All CPUs are trying to go to C3
 312                                  * Disable bus master arbitration
 313                                  */
 314                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
 315                                                   ACPI_MTX_DO_NOT_LOCK);
 316                         }
 317                 } else {
 318                         /* SMP with no shared cache... Invalidate cache  */
 319                         ACPI_FLUSH_CPU_CACHE();
 320                 }
 321
 322                 /* Get start time (ticks) */
 323                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 324                 /* Invoke C3 */
 325                 inb(cx->address);
 326                 /* Dummy op - must do something useless after P_LVL3 read */
 327                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 328                 /* Get end time (ticks) */
 329                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 330                 if (pr->flags.bm_check) {
 331                         /* Enable bus master arbitration */
 332                         atomic_dec(&c3_cpu_count);
 333                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
 334                                           ACPI_MTX_DO_NOT_LOCK);
 335                 }
 336
 337                 /* Re-enable interrupts */
 338                 local_irq_enable();
 339                 /* Compute time (ticks) that we were actually asleep */
 340                 sleep_ticks =
 341                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 342                 break;
 343
 344         default:
 345                 local_irq_enable();
 346                 return;
 347         }
 348
 349         next_state = pr->power.state;
 350
 351         /*
 352          * Promotion?
 353          * ----------
 354          * Track the number of longs (time asleep is greater than threshold)
 355          * and promote when the count threshold is reached.  Note that bus
 356          * mastering activity may prevent promotions.
 357          * Do not promote above max_cstate.
 358          */
 359         if (cx->promotion.state &&
 360             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 361                 if (sleep_ticks > cx->promotion.threshold.ticks) {
 362                         cx->promotion.count++;
 363                         cx->demotion.count = 0;
 364                         if (cx->promotion.count >=
 365                             cx->promotion.threshold.count) {
 366                                 if (pr->flags.bm_check) {
 367                                         if (!
 368                                             (pr->power.bm_activity & cx->
 369                                              promotion.threshold.bm)) {
 370                                                 next_state =
 371                                                     cx->promotion.state;
 372                                                 goto end;
 373                                         }
 374                                 } else {
 375                                         next_state = cx->promotion.state;
 376                                         goto end;
 377                                 }
 378                         }
 379                 }
 380         }
 381
 382         /*
 383          * Demotion?
 384          * ---------
 385          * Track the number of shorts (time asleep is less than time threshold)
 386          * and demote when the usage threshold is reached.
 387          */
 388         if (cx->demotion.state) {
 389                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 390                         cx->demotion.count++;
 391                         cx->promotion.count = 0;
 392                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 393                                 next_state = cx->demotion.state;
 394                                 goto end;
 395                         }
 396                 }
 397         }
 398
 399       end:
 400         /*
 401          * Demote if current state exceeds max_cstate
 402          */
 403         if ((pr->power.state - pr->power.states) > max_cstate) {
 404                 if (cx->demotion.state)
 405                         next_state = cx->demotion.state;
 406         }
 407
 408         /*
 409          * New Cx State?
 410          * -------------
 411          * If we're going to start using a new Cx state we must clean up
 412          * from the previous and prepare to use the new.
 413          */
 414         if (next_state != pr->power.state)
 415                 acpi_processor_power_activate(pr, next_state);
 416
 417         return;
 418
 419       easy_out:
 420         /* do C1 instead of busy loop */
 421         if (pm_idle_save)
 422                 pm_idle_save();
 423         else
 424                 safe_halt();
 425         return;
 426 }
 427
 428 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 429 {
 430         unsigned int i;
 431         unsigned int state_is_set = 0;
 432         struct acpi_processor_cx *lower = NULL;
 433         struct acpi_processor_cx *higher = NULL;
 434         struct acpi_processor_cx *cx;
 435
 436         ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
 437
 438         if (!pr)
 439                 return_VALUE(-EINVAL);
 440
 441         /*
 442          * This function sets the default Cx state policy (OS idle handler).
 443          * Our scheme is to promote quickly to C2 but more conservatively
 444          * to C3.  We're favoring C2  for its characteristics of low latency
 445          * (quick response), good power savings, and ability to allow bus
 446          * mastering activity.  Note that the Cx state policy is completely
 447          * customizable and can be altered dynamically.
 448          */
 449
 450         /* startup state */
 451         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 452                 cx = &pr->power.states[i];
 453                 if (!cx->valid)
 454                         continue;
 455
 456                 if (!state_is_set)
 457                         pr->power.state = cx;
 458                 state_is_set++;
 459                 break;
 460         }
 461
 462         if (!state_is_set)
 463                 return_VALUE(-ENODEV);
 464
 465         /* demotion */
 466         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 467                 cx = &pr->power.states[i];
 468                 if (!cx->valid)
 469                         continue;
 470
 471                 if (lower) {
 472                         cx->demotion.state = lower;
 473                         cx->demotion.threshold.ticks = cx->latency_ticks;
 474                         cx->demotion.threshold.count = 1;
 475                         if (cx->type == ACPI_STATE_C3)
 476                                 cx->demotion.threshold.bm = bm_history;
 477                 }
 478
 479                 lower = cx;
 480         }
 481
 482         /* promotion */
 483         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 484                 cx = &pr->power.states[i];
 485                 if (!cx->valid)
 486                         continue;
 487
 488                 if (higher) {
 489                         cx->promotion.state = higher;
 490                         cx->promotion.threshold.ticks = cx->latency_ticks;
 491                         if (cx->type >= ACPI_STATE_C2)
 492                                 cx->promotion.threshold.count = 4;
 493                         else
 494                                 cx->promotion.threshold.count = 10;
 495                         if (higher->type == ACPI_STATE_C3)
 496                                 cx->promotion.threshold.bm = bm_history;
 497                 }
 498
 499                 higher = cx;
 500         }
 501
 502         return_VALUE(0);
 503 }
 504
 505 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 506 {
 507         int i;
 508
 509         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
 510
 511         if (!pr)
 512                 return_VALUE(-EINVAL);
 513
 514         if (!pr->pblk)
 515                 return_VALUE(-ENODEV);
 516
 517         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 518                 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
 519
 520         /* if info is obtained from pblk/fadt, type equals state */
 521         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 522         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 523         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 524
 525         /* the C0 state only exists as a filler in our array,
 526          * and all processors need to support C1 */
 527         pr->power.states[ACPI_STATE_C0].valid = 1;
 528         pr->power.states[ACPI_STATE_C1].valid = 1;
 529
 530         /* determine C2 and C3 address from pblk */
 531         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 532         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 533
 534         /* determine latencies from FADT */
 535         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 536         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 537
 538         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 539                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 540                           pr->power.states[ACPI_STATE_C2].address,
 541                           pr->power.states[ACPI_STATE_C3].address));
 542
 543         return_VALUE(0);
 544 }
 545
 546 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
 547 {
 548         int i;
 549
 550         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
 551
 552         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 553                 memset(&(pr->power.states[i]), 0,
 554                        sizeof(struct acpi_processor_cx));
 555
 556         /* if info is obtained from pblk/fadt, type equals state */
 557         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 558         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 559         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 560
 561         /* the C0 state only exists as a filler in our array,
 562          * and all processors need to support C1 */
 563         pr->power.states[ACPI_STATE_C0].valid = 1;
 564         pr->power.states[ACPI_STATE_C1].valid = 1;
 565
 566         return_VALUE(0);
 567 }
 568
 569 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 570 {
 571         acpi_status status = 0;
 572         acpi_integer count;
 573         int i;
 574         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 575         union acpi_object *cst;
 576
 577         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
 578
 579         if (nocst)
 580                 return_VALUE(-ENODEV);
 581
 582         pr->power.count = 0;
 583         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 584                 memset(&(pr->power.states[i]), 0,
 585                        sizeof(struct acpi_processor_cx));
 586
 587         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 588         if (ACPI_FAILURE(status)) {
 589                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 590                 return_VALUE(-ENODEV);
 591         }
 592
 593         cst = (union acpi_object *)buffer.pointer;
 594
 595         /* There must be at least 2 elements */
 596         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 597                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 598                                   "not enough elements in _CST\n"));
 599                 status = -EFAULT;
 600                 goto end;
 601         }
 602
 603         count = cst->package.elements[0].integer.value;
 604
 605         /* Validate number of power states. */
 606         if (count < 1 || count != cst->package.count - 1) {
 607                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 608                                   "count given by _CST is not valid\n"));
 609                 status = -EFAULT;
 610                 goto end;
 611         }
 612
 613         /* We support up to ACPI_PROCESSOR_MAX_POWER. */
 614         if (count > ACPI_PROCESSOR_MAX_POWER) {
 615                 printk(KERN_WARNING
 616                        "Limiting number of power states to max (%d)\n",
 617                        ACPI_PROCESSOR_MAX_POWER);
 618                 printk(KERN_WARNING
 619                        "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 620                 count = ACPI_PROCESSOR_MAX_POWER;
 621         }
 622
 623         /* Tell driver that at least _CST is supported. */
 624         pr->flags.has_cst = 1;
 625
 626         for (i = 1; i <= count; i++) {
 627                 union acpi_object *element;
 628                 union acpi_object *obj;
 629                 struct acpi_power_register *reg;
 630                 struct acpi_processor_cx cx;
 631
 632                 memset(&cx, 0, sizeof(cx));
 633
 634                 element = (union acpi_object *)&(cst->package.elements[i]);
 635                 if (element->type != ACPI_TYPE_PACKAGE)
 636                         continue;
 637
 638                 if (element->package.count != 4)
 639                         continue;
 640
 641                 obj = (union acpi_object *)&(element->package.elements[0]);
 642
 643                 if (obj->type != ACPI_TYPE_BUFFER)
 644                         continue;
 645
 646                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 647
 648                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 649                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 650                         continue;
 651
 652                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
 653                     0 : reg->address;
 654
 655                 /* There should be an easy way to extract an integer... */
 656                 obj = (union acpi_object *)&(element->package.elements[1]);
 657                 if (obj->type != ACPI_TYPE_INTEGER)
 658                         continue;
 659
 660                 cx.type = obj->integer.value;
 661
 662                 if ((cx.type != ACPI_STATE_C1) &&
 663                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
 664                         continue;
 665
 666                 if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3))
 667                         continue;
 668
 669                 obj = (union acpi_object *)&(element->package.elements[2]);
 670                 if (obj->type != ACPI_TYPE_INTEGER)
 671                         continue;
 672
 673                 cx.latency = obj->integer.value;
 674
 675                 obj = (union acpi_object *)&(element->package.elements[3]);
 676                 if (obj->type != ACPI_TYPE_INTEGER)
 677                         continue;
 678
 679                 cx.power = obj->integer.value;
 680
 681                 (pr->power.count)++;
 682                 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
 683         }
 684
 685         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 686                           pr->power.count));
 687
 688         /* Validate number of power states discovered */
 689         if (pr->power.count < 2)
 690                 status = -ENODEV;
 691
 692       end:
 693         acpi_os_free(buffer.pointer);
 694
 695         return_VALUE(status);
 696 }
 697
 698 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 699 {
 700         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
 701
 702         if (!cx->address)
 703                 return_VOID;
 704
 705         /*
 706          * C2 latency must be less than or equal to 100
 707          * microseconds.
 708          */
 709         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 710                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 711                                   "latency too large [%d]\n", cx->latency));
 712                 return_VOID;
 713         }
 714
 715         /*
 716          * Otherwise we've met all of our C2 requirements.
 717          * Normalize the C2 latency to expidite policy
 718          */
 719         cx->valid = 1;
 720         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 721
 722         return_VOID;
 723 }
 724
 725 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 726                                            struct acpi_processor_cx *cx)
 727 {
 728         static int bm_check_flag;
 729
 730         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
 731
 732         if (!cx->address)
 733                 return_VOID;
 734
 735         /*
 736          * C3 latency must be less than or equal to 1000
 737          * microseconds.
 738          */
 739         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 740                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 741                                   "latency too large [%d]\n", cx->latency));
 742                 return_VOID;
 743         }
 744
 745         /*
 746          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 747          * DMA transfers are used by any ISA device to avoid livelock.
 748          * Note that we could disable Type-F DMA (as recommended by
 749          * the erratum), but this is known to disrupt certain ISA
 750          * devices thus we take the conservative approach.
 751          */
 752         else if (errata.piix4.fdma) {
 753                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 754                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 755                 return_VOID;
 756         }
 757
 758         /* All the logic here assumes flags.bm_check is same across all CPUs */
 759         if (!bm_check_flag) {
 760                 /* Determine whether bm_check is needed based on CPU  */
 761                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 762                 bm_check_flag = pr->flags.bm_check;
 763         } else {
 764                 pr->flags.bm_check = bm_check_flag;
 765         }
 766
 767         if (pr->flags.bm_check) {
 768                 /* bus mastering control is necessary */
 769                 if (!pr->flags.bm_control) {
 770                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 771                                           "C3 support requires bus mastering control\n"));
 772                         return_VOID;
 773                 }
 774         } else {
 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 static int acpi_processor_power_verify(struct acpi_processor *pr)
 802 {
 803         unsigned int i;
 804         unsigned int working = 0;
 805
 806         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 807                 struct acpi_processor_cx *cx = &pr->power.states[i];
 808
 809                 switch (cx->type) {
 810                 case ACPI_STATE_C1:
 811                         cx->valid = 1;
 812                         break;
 813
 814                 case ACPI_STATE_C2:
 815                         acpi_processor_power_verify_c2(cx);
 816                         break;
 817
 818                 case ACPI_STATE_C3:
 819                         acpi_processor_power_verify_c3(pr, cx);
 820                         break;
 821                 }
 822
 823                 if (cx->valid)
 824                         working++;
 825         }
 826
 827         return (working);
 828 }
 829
 830 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 831 {
 832         unsigned int i;
 833         int result;
 834
 835         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
 836
 837         /* NOTE: the idle thread may not be running while calling
 838          * this function */
 839
 840         result = acpi_processor_get_power_info_cst(pr);
 841         if ((result) || (acpi_processor_power_verify(pr) < 2)) {
 842                 result = acpi_processor_get_power_info_fadt(pr);
 843                 if ((result) || (acpi_processor_power_verify(pr) < 2))
 844                         result = acpi_processor_get_power_info_default_c1(pr);
 845         }
 846
 847         /*
 848          * Set Default Policy
 849          * ------------------
 850          * Now that we know which states are supported, set the default
 851          * policy.  Note that this policy can be changed dynamically
 852          * (e.g. encourage deeper sleeps to conserve battery life when
 853          * not on AC).
 854          */
 855         result = acpi_processor_set_power_policy(pr);
 856         if (result)
 857                 return_VALUE(result);
 858
 859         /*
 860          * if one state of type C2 or C3 is available, mark this
 861          * CPU as being "idle manageable"
 862          */
 863         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 864                 if (pr->power.states[i].valid) {
 865                         pr->power.count = i;
 866                         pr->flags.power = 1;
 867                 }
 868         }
 869
 870         return_VALUE(0);
 871 }
 872
 873 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 874 {
 875         int result = 0;
 876
 877         ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
 878
 879         if (!pr)
 880                 return_VALUE(-EINVAL);
 881
 882         if (nocst) {
 883                 return_VALUE(-ENODEV);
 884         }
 885
 886         if (!pr->flags.power_setup_done)
 887                 return_VALUE(-ENODEV);
 888
 889         /* Fall back to the default idle loop */
 890         pm_idle = pm_idle_save;
 891         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
 892
 893         pr->flags.power = 0;
 894         result = acpi_processor_get_power_info(pr);
 895         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
 896                 pm_idle = acpi_processor_idle;
 897
 898         return_VALUE(result);
 899 }
 900
 901 /* proc interface */
 902
 903 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
 904 {
 905         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 906         unsigned int i;
 907
 908         ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
 909
 910         if (!pr)
 911                 goto end;
 912
 913         seq_printf(seq, "active state:            C%zd\n"
 914                    "max_cstate:              C%d\n"
 915                    "bus master activity:     %08x\n",
 916                    pr->power.state ? pr->power.state - pr->power.states : 0,
 917                    max_cstate, (unsigned)pr->power.bm_activity);
 918
 919         seq_puts(seq, "states:\n");
 920
 921         for (i = 1; i <= pr->power.count; i++) {
 922                 seq_printf(seq, "   %cC%d:                  ",
 923                            (&pr->power.states[i] ==
 924                             pr->power.state ? '*' : ' '), i);
 925
 926                 if (!pr->power.states[i].valid) {
 927                         seq_puts(seq, "<not supported>\n");
 928                         continue;
 929                 }
 930
 931                 switch (pr->power.states[i].type) {
 932                 case ACPI_STATE_C1:
 933                         seq_printf(seq, "type[C1] ");
 934                         break;
 935                 case ACPI_STATE_C2:
 936                         seq_printf(seq, "type[C2] ");
 937                         break;
 938                 case ACPI_STATE_C3:
 939                         seq_printf(seq, "type[C3] ");
 940                         break;
 941                 default:
 942                         seq_printf(seq, "type[--] ");
 943                         break;
 944                 }
 945
 946                 if (pr->power.states[i].promotion.state)
 947                         seq_printf(seq, "promotion[C%zd] ",
 948                                    (pr->power.states[i].promotion.state -
 949                                     pr->power.states));
 950                 else
 951                         seq_puts(seq, "promotion[--] ");
 952
 953                 if (pr->power.states[i].demotion.state)
 954                         seq_printf(seq, "demotion[C%zd] ",
 955                                    (pr->power.states[i].demotion.state -
 956                                     pr->power.states));
 957                 else
 958                         seq_puts(seq, "demotion[--] ");
 959
 960                 seq_printf(seq, "latency[%03d] usage[%08d]\n",
 961                            pr->power.states[i].latency,
 962                            pr->power.states[i].usage);
 963         }
 964
 965       end:
 966         return_VALUE(0);
 967 }
 968
 969 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
 970 {
 971         return single_open(file, acpi_processor_power_seq_show,
 972                            PDE(inode)->data);
 973 }
 974
 975 static struct file_operations acpi_processor_power_fops = {
 976         .open = acpi_processor_power_open_fs,
 977         .read = seq_read,
 978         .llseek = seq_lseek,
 979         .release = single_release,
 980 };
 981
 982 int acpi_processor_power_init(struct acpi_processor *pr,
 983                               struct acpi_device *device)
 984 {
 985         acpi_status status = 0;
 986         static int first_run = 0;
 987         struct proc_dir_entry *entry = NULL;
 988         unsigned int i;
 989
 990         ACPI_FUNCTION_TRACE("acpi_processor_power_init");
 991
 992         if (!first_run) {
 993                 dmi_check_system(processor_power_dmi_table);
 994                 if (max_cstate < ACPI_C_STATES_MAX)
 995                         printk(KERN_NOTICE
 996                                "ACPI: processor limited to max C-state %d\n",
 997                                max_cstate);
 998                 first_run++;
 999         }
1000
1001         if (!pr)
1002                 return_VALUE(-EINVAL);
1003
1004         if (acpi_fadt.cst_cnt && !nocst) {
1005                 status =
1006                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1007                 if (ACPI_FAILURE(status)) {
1008                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1009                                           "Notifying BIOS of _CST ability failed\n"));
1010                 }
1011         }
1012
1013         acpi_processor_power_init_pdc(&(pr->power), pr->id);
1014         acpi_processor_set_pdc(pr, pr->power.pdc);
1015         acpi_processor_get_power_info(pr);
1016
1017         /*
1018          * Install the idle handler if processor power management is supported.
1019          * Note that we use previously set idle handler will be used on
1020          * platforms that only support C1.
1021          */
1022         if ((pr->flags.power) && (!boot_option_idle_override)) {
1023                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1024                 for (i = 1; i <= pr->power.count; i++)
1025                         if (pr->power.states[i].valid)
1026                                 printk(" C%d[C%d]", i,
1027                                        pr->power.states[i].type);
1028                 printk(")\n");
1029
1030                 if (pr->id == 0) {
1031                         pm_idle_save = pm_idle;
1032                         pm_idle = acpi_processor_idle;
1033                 }
1034         }
1035
1036         /* 'power' [R] */
1037         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1038                                   S_IRUGO, acpi_device_dir(device));
1039         if (!entry)
1040                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1041                                   "Unable to create '%s' fs entry\n",
1042                                   ACPI_PROCESSOR_FILE_POWER));
1043         else {
1044                 entry->proc_fops = &acpi_processor_power_fops;
1045                 entry->data = acpi_driver_data(device);
1046                 entry->owner = THIS_MODULE;
1047         }
1048
1049         pr->flags.power_setup_done = 1;
1050
1051         return_VALUE(0);
1052 }
1053
1054 int acpi_processor_power_exit(struct acpi_processor *pr,
1055                               struct acpi_device *device)
1056 {
1057         ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
1058
1059         pr->flags.power_setup_done = 0;
1060
1061         if (acpi_device_dir(device))
1062                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1063                                   acpi_device_dir(device));
1064
1065         /* Unregister the idle handler when processor #0 is removed. */
1066         if (pr->id == 0) {
1067                 pm_idle = pm_idle_save;
1068
1069                 /*
1070                  * We are about to unload the current idle thread pm callback
1071                  * (pm_idle), Wait for all processors to update cached/local
1072                  * copies of pm_idle before proceeding.
1073                  */
1074                 cpu_idle_wait();
1075         }
1076
1077         return_VALUE(0);
1078 }