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, 2005 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 #include <linux/sched.h>        /* need_resched() */
  41 #include <linux/latency.h>
  42 #include <linux/clockchips.h>
  43
  44 /*
  45  * Include the apic definitions for x86 to have the APIC timer related defines
  46  * available also for UP (on SMP it gets magically included via linux/smp.h).
  47  * asm/acpi.h is not an option, as it would require more include magic. Also
  48  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  49  */
  50 #ifdef CONFIG_X86
  51 #include <asm/apic.h>
  52 #endif
  53
  54 /*
  55  * Include the apic definitions for x86 to have the APIC timer related defines
  56  * available also for UP (on SMP it gets magically included via linux/smp.h).
  57  */
  58 #ifdef CONFIG_X86
  59 #include <asm/apic.h>
  60 #endif
  61
  62 #include <asm/io.h>
  63 #include <asm/uaccess.h>
  64
  65 #include <acpi/acpi_bus.h>
  66 #include <acpi/processor.h>
  67
  68 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  69 #define ACPI_PROCESSOR_CLASS            "processor"
  70 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  71 ACPI_MODULE_NAME("processor_idle");
  72 #define ACPI_PROCESSOR_FILE_POWER       "power"
  73 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  74 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  75 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  76 static void (*pm_idle_save) (void) __read_mostly;
  77 module_param(max_cstate, uint, 0644);
  78
  79 static unsigned int nocst __read_mostly;
  80 module_param(nocst, uint, 0000);
  81
  82 /*
  83  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  84  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  85  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  86  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  87  * reduce history for more aggressive entry into C3
  88  */
  89 static unsigned int bm_history __read_mostly =
  90     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  91 module_param(bm_history, uint, 0644);
  92 /* --------------------------------------------------------------------------
  93                                 Power Management
  94    -------------------------------------------------------------------------- */
  95
  96 /*
  97  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  98  * For now disable this. Probably a bug somewhere else.
  99  *
 100  * To skip this limit, boot/load with a large max_cstate limit.
 101  */
 102 static int set_max_cstate(struct dmi_system_id *id)
 103 {
 104         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
 105                 return 0;
 106
 107         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
 108                " Override with \"processor.max_cstate=%d\"\n", id->ident,
 109                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
 110
 111         max_cstate = (long)id->driver_data;
 112
 113         return 0;
 114 }
 115
 116 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
 117    callers to only run once -AK */
 118 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 119         { set_max_cstate, "IBM ThinkPad R40e", {
 120           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 121           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 122         { set_max_cstate, "IBM ThinkPad R40e", {
 123           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 124           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 125         { set_max_cstate, "IBM ThinkPad R40e", {
 126           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 127           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 128         { set_max_cstate, "IBM ThinkPad R40e", {
 129           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 130           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 131         { set_max_cstate, "IBM ThinkPad R40e", {
 132           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 133           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 134         { set_max_cstate, "IBM ThinkPad R40e", {
 135           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 136           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 137         { set_max_cstate, "IBM ThinkPad R40e", {
 138           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 139           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 140         { set_max_cstate, "IBM ThinkPad R40e", {
 141           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 142           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 143         { set_max_cstate, "IBM ThinkPad R40e", {
 144           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 145           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 146         { set_max_cstate, "IBM ThinkPad R40e", {
 147           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 148           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 149         { set_max_cstate, "IBM ThinkPad R40e", {
 150           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 151           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 152         { set_max_cstate, "IBM ThinkPad R40e", {
 153           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 154           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 155         { set_max_cstate, "IBM ThinkPad R40e", {
 156           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 157           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 158         { set_max_cstate, "IBM ThinkPad R40e", {
 159           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 160           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 161         { set_max_cstate, "IBM ThinkPad R40e", {
 162           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 163           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 164         { set_max_cstate, "IBM ThinkPad R40e", {
 165           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 166           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 167         { set_max_cstate, "Medion 41700", {
 168           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 169           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 170         { set_max_cstate, "Clevo 5600D", {
 171           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 172           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 173          (void *)2},
 174         {},
 175 };
 176
 177 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 178 {
 179         if (t2 >= t1)
 180                 return (t2 - t1);
 181         else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 182                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 183         else
 184                 return ((0xFFFFFFFF - t1) + t2);
 185 }
 186
 187 static void
 188 acpi_processor_power_activate(struct acpi_processor *pr,
 189                               struct acpi_processor_cx *new)
 190 {
 191         struct acpi_processor_cx *old;
 192
 193         if (!pr || !new)
 194                 return;
 195
 196         old = pr->power.state;
 197
 198         if (old)
 199                 old->promotion.count = 0;
 200         new->demotion.count = 0;
 201
 202         /* Cleanup from old state. */
 203         if (old) {
 204                 switch (old->type) {
 205                 case ACPI_STATE_C3:
 206                         /* Disable bus master reload */
 207                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 208                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 209                         break;
 210                 }
 211         }
 212
 213         /* Prepare to use new state. */
 214         switch (new->type) {
 215         case ACPI_STATE_C3:
 216                 /* Enable bus master reload */
 217                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 218                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 219                 break;
 220         }
 221
 222         pr->power.state = new;
 223
 224         return;
 225 }
 226
 227 static void acpi_safe_halt(void)
 228 {
 229         current_thread_info()->status &= ~TS_POLLING;
 230         /*
 231          * TS_POLLING-cleared state must be visible before we
 232          * test NEED_RESCHED:
 233          */
 234         smp_mb();
 235         if (!need_resched())
 236                 safe_halt();
 237         current_thread_info()->status |= TS_POLLING;
 238 }
 239
 240 static atomic_t c3_cpu_count;
 241
 242 /* Common C-state entry for C2, C3, .. */
 243 static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
 244 {
 245         if (cstate->space_id == ACPI_CSTATE_FFH) {
 246                 /* Call into architectural FFH based C-state */
 247                 acpi_processor_ffh_cstate_enter(cstate);
 248         } else {
 249                 int unused;
 250                 /* IO port based C-state */
 251                 inb(cstate->address);
 252                 /* Dummy wait op - must do something useless after P_LVL2 read
 253                    because chipsets cannot guarantee that STPCLK# signal
 254                    gets asserted in time to freeze execution properly. */
 255                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
 256         }
 257 }
 258
 259 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 260
 261 /*
 262  * Some BIOS implementations switch to C3 in the published C2 state.
 263  * This seems to be a common problem on AMD boxen, but other vendors
 264  * are affected too. We pick the most conservative approach: we assume
 265  * that the local APIC stops in both C2 and C3.
 266  */
 267 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 268                                    struct acpi_processor_cx *cx)
 269 {
 270         struct acpi_processor_power *pwr = &pr->power;
 271         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 272
 273         /*
 274          * Check, if one of the previous states already marked the lapic
 275          * unstable
 276          */
 277         if (pwr->timer_broadcast_on_state < state)
 278                 return;
 279
 280         if (cx->type >= type)
 281                 pr->power.timer_broadcast_on_state = state;
 282 }
 283
 284 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)
 285 {
 286 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 287         unsigned long reason;
 288
 289         reason = pr->power.timer_broadcast_on_state < INT_MAX ?
 290                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
 291
 292         clockevents_notify(reason, &pr->id);
 293 #else
 294         cpumask_t mask = cpumask_of_cpu(pr->id);
 295
 296         if (pr->power.timer_broadcast_on_state < INT_MAX)
 297                 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
 298         else
 299                 on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
 300 #endif
 301 }
 302
 303 /* Power(C) State timer broadcast control */
 304 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 305                                        struct acpi_processor_cx *cx,
 306                                        int broadcast)
 307 {
 308 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 309
 310         int state = cx - pr->power.states;
 311
 312         if (state >= pr->power.timer_broadcast_on_state) {
 313                 unsigned long reason;
 314
 315                 reason = broadcast ?  CLOCK_EVT_NOTIFY_BROADCAST_ENTER :
 316                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT;
 317                 clockevents_notify(reason, &pr->id);
 318         }
 319 #endif
 320 }
 321
 322 #else
 323
 324 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 325                                    struct acpi_processor_cx *cstate) { }
 326 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { }
 327 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 328                                        struct acpi_processor_cx *cx,
 329                                        int broadcast)
 330 {
 331 }
 332
 333 #endif
 334
 335 static void acpi_processor_idle(void)
 336 {
 337         struct acpi_processor *pr = NULL;
 338         struct acpi_processor_cx *cx = NULL;
 339         struct acpi_processor_cx *next_state = NULL;
 340         int sleep_ticks = 0;
 341         u32 t1, t2 = 0;
 342
 343         pr = processors[smp_processor_id()];
 344         if (!pr)
 345                 return;
 346
 347         /*
 348          * Interrupts must be disabled during bus mastering calculations and
 349          * for C2/C3 transitions.
 350          */
 351         local_irq_disable();
 352
 353         /*
 354          * Check whether we truly need to go idle, or should
 355          * reschedule:
 356          */
 357         if (unlikely(need_resched())) {
 358                 local_irq_enable();
 359                 return;
 360         }
 361
 362         cx = pr->power.state;
 363         if (!cx) {
 364                 if (pm_idle_save)
 365                         pm_idle_save();
 366                 else
 367                         acpi_safe_halt();
 368                 return;
 369         }
 370
 371         /*
 372          * Check BM Activity
 373          * -----------------
 374          * Check for bus mastering activity (if required), record, and check
 375          * for demotion.
 376          */
 377         if (pr->flags.bm_check) {
 378                 u32 bm_status = 0;
 379                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 380
 381                 if (diff > 31)
 382                         diff = 31;
 383
 384                 pr->power.bm_activity <<= diff;
 385
 386                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 387                 if (bm_status) {
 388                         pr->power.bm_activity |= 0x1;
 389                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 390                 }
 391                 /*
 392                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 393                  * the true state of bus mastering activity; forcing us to
 394                  * manually check the BMIDEA bit of each IDE channel.
 395                  */
 396                 else if (errata.piix4.bmisx) {
 397                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 398                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 399                                 pr->power.bm_activity |= 0x1;
 400                 }
 401
 402                 pr->power.bm_check_timestamp = jiffies;
 403
 404                 /*
 405                  * If bus mastering is or was active this jiffy, demote
 406                  * to avoid a faulty transition.  Note that the processor
 407                  * won't enter a low-power state during this call (to this
 408                  * function) but should upon the next.
 409                  *
 410                  * TBD: A better policy might be to fallback to the demotion
 411                  *      state (use it for this quantum only) istead of
 412                  *      demoting -- and rely on duration as our sole demotion
 413                  *      qualification.  This may, however, introduce DMA
 414                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 415                  */
 416                 if ((pr->power.bm_activity & 0x1) &&
 417                     cx->demotion.threshold.bm) {
 418                         local_irq_enable();
 419                         next_state = cx->demotion.state;
 420                         goto end;
 421                 }
 422         }
 423
 424 #ifdef CONFIG_HOTPLUG_CPU
 425         /*
 426          * Check for P_LVL2_UP flag before entering C2 and above on
 427          * an SMP system. We do it here instead of doing it at _CST/P_LVL
 428          * detection phase, to work cleanly with logical CPU hotplug.
 429          */
 430         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 431             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 432                 cx = &pr->power.states[ACPI_STATE_C1];
 433 #endif
 434
 435         /*
 436          * Sleep:
 437          * ------
 438          * Invoke the current Cx state to put the processor to sleep.
 439          */
 440         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 441                 current_thread_info()->status &= ~TS_POLLING;
 442                 /*
 443                  * TS_POLLING-cleared state must be visible before we
 444                  * test NEED_RESCHED:
 445                  */
 446                 smp_mb();
 447                 if (need_resched()) {
 448                         current_thread_info()->status |= TS_POLLING;
 449                         local_irq_enable();
 450                         return;
 451                 }
 452         }
 453
 454         switch (cx->type) {
 455
 456         case ACPI_STATE_C1:
 457                 /*
 458                  * Invoke C1.
 459                  * Use the appropriate idle routine, the one that would
 460                  * be used without acpi C-states.
 461                  */
 462                 if (pm_idle_save)
 463                         pm_idle_save();
 464                 else
 465                         acpi_safe_halt();
 466
 467                 /*
 468                  * TBD: Can't get time duration while in C1, as resumes
 469                  *      go to an ISR rather than here.  Need to instrument
 470                  *      base interrupt handler.
 471                  */
 472                 sleep_ticks = 0xFFFFFFFF;
 473                 break;
 474
 475         case ACPI_STATE_C2:
 476                 /* Get start time (ticks) */
 477                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 478                 /* Invoke C2 */
 479                 acpi_state_timer_broadcast(pr, cx, 1);
 480                 acpi_cstate_enter(cx);
 481                 /* Get end time (ticks) */
 482                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 483
 484 #ifdef CONFIG_GENERIC_TIME
 485                 /* TSC halts in C2, so notify users */
 486                 mark_tsc_unstable();
 487 #endif
 488                 /* Re-enable interrupts */
 489                 local_irq_enable();
 490                 current_thread_info()->status |= TS_POLLING;
 491                 /* Compute time (ticks) that we were actually asleep */
 492                 sleep_ticks =
 493                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 494                 acpi_state_timer_broadcast(pr, cx, 0);
 495                 break;
 496
 497         case ACPI_STATE_C3:
 498
 499                 if (pr->flags.bm_check) {
 500                         if (atomic_inc_return(&c3_cpu_count) ==
 501                             num_online_cpus()) {
 502                                 /*
 503                                  * All CPUs are trying to go to C3
 504                                  * Disable bus master arbitration
 505                                  */
 506                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
 507                         }
 508                 } else {
 509                         /* SMP with no shared cache... Invalidate cache  */
 510                         ACPI_FLUSH_CPU_CACHE();
 511                 }
 512
 513                 /* Get start time (ticks) */
 514                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 515                 /* Invoke C3 */
 516                 acpi_state_timer_broadcast(pr, cx, 1);
 517                 acpi_cstate_enter(cx);
 518                 /* Get end time (ticks) */
 519                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 520                 if (pr->flags.bm_check) {
 521                         /* Enable bus master arbitration */
 522                         atomic_dec(&c3_cpu_count);
 523                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
 524                 }
 525
 526 #ifdef CONFIG_GENERIC_TIME
 527                 /* TSC halts in C3, so notify users */
 528                 mark_tsc_unstable();
 529 #endif
 530                 /* Re-enable interrupts */
 531                 local_irq_enable();
 532                 current_thread_info()->status |= TS_POLLING;
 533                 /* Compute time (ticks) that we were actually asleep */
 534                 sleep_ticks =
 535                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 536                 acpi_state_timer_broadcast(pr, cx, 0);
 537                 break;
 538
 539         default:
 540                 local_irq_enable();
 541                 return;
 542         }
 543         cx->usage++;
 544         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 545                 cx->time += sleep_ticks;
 546
 547         next_state = pr->power.state;
 548
 549 #ifdef CONFIG_HOTPLUG_CPU
 550         /* Don't do promotion/demotion */
 551         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 552             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
 553                 next_state = cx;
 554                 goto end;
 555         }
 556 #endif
 557
 558         /*
 559          * Promotion?
 560          * ----------
 561          * Track the number of longs (time asleep is greater than threshold)
 562          * and promote when the count threshold is reached.  Note that bus
 563          * mastering activity may prevent promotions.
 564          * Do not promote above max_cstate.
 565          */
 566         if (cx->promotion.state &&
 567             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 568                 if (sleep_ticks > cx->promotion.threshold.ticks &&
 569                   cx->promotion.state->latency <= system_latency_constraint()) {
 570                         cx->promotion.count++;
 571                         cx->demotion.count = 0;
 572                         if (cx->promotion.count >=
 573                             cx->promotion.threshold.count) {
 574                                 if (pr->flags.bm_check) {
 575                                         if (!
 576                                             (pr->power.bm_activity & cx->
 577                                              promotion.threshold.bm)) {
 578                                                 next_state =
 579                                                     cx->promotion.state;
 580                                                 goto end;
 581                                         }
 582                                 } else {
 583                                         next_state = cx->promotion.state;
 584                                         goto end;
 585                                 }
 586                         }
 587                 }
 588         }
 589
 590         /*
 591          * Demotion?
 592          * ---------
 593          * Track the number of shorts (time asleep is less than time threshold)
 594          * and demote when the usage threshold is reached.
 595          */
 596         if (cx->demotion.state) {
 597                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 598                         cx->demotion.count++;
 599                         cx->promotion.count = 0;
 600                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 601                                 next_state = cx->demotion.state;
 602                                 goto end;
 603                         }
 604                 }
 605         }
 606
 607       end:
 608         /*
 609          * Demote if current state exceeds max_cstate
 610          * or if the latency of the current state is unacceptable
 611          */
 612         if ((pr->power.state - pr->power.states) > max_cstate ||
 613                 pr->power.state->latency > system_latency_constraint()) {
 614                 if (cx->demotion.state)
 615                         next_state = cx->demotion.state;
 616         }
 617
 618         /*
 619          * New Cx State?
 620          * -------------
 621          * If we're going to start using a new Cx state we must clean up
 622          * from the previous and prepare to use the new.
 623          */
 624         if (next_state != pr->power.state)
 625                 acpi_processor_power_activate(pr, next_state);
 626 }
 627
 628 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 629 {
 630         unsigned int i;
 631         unsigned int state_is_set = 0;
 632         struct acpi_processor_cx *lower = NULL;
 633         struct acpi_processor_cx *higher = NULL;
 634         struct acpi_processor_cx *cx;
 635
 636
 637         if (!pr)
 638                 return -EINVAL;
 639
 640         /*
 641          * This function sets the default Cx state policy (OS idle handler).
 642          * Our scheme is to promote quickly to C2 but more conservatively
 643          * to C3.  We're favoring C2  for its characteristics of low latency
 644          * (quick response), good power savings, and ability to allow bus
 645          * mastering activity.  Note that the Cx state policy is completely
 646          * customizable and can be altered dynamically.
 647          */
 648
 649         /* startup state */
 650         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 651                 cx = &pr->power.states[i];
 652                 if (!cx->valid)
 653                         continue;
 654
 655                 if (!state_is_set)
 656                         pr->power.state = cx;
 657                 state_is_set++;
 658                 break;
 659         }
 660
 661         if (!state_is_set)
 662                 return -ENODEV;
 663
 664         /* demotion */
 665         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 666                 cx = &pr->power.states[i];
 667                 if (!cx->valid)
 668                         continue;
 669
 670                 if (lower) {
 671                         cx->demotion.state = lower;
 672                         cx->demotion.threshold.ticks = cx->latency_ticks;
 673                         cx->demotion.threshold.count = 1;
 674                         if (cx->type == ACPI_STATE_C3)
 675                                 cx->demotion.threshold.bm = bm_history;
 676                 }
 677
 678                 lower = cx;
 679         }
 680
 681         /* promotion */
 682         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 683                 cx = &pr->power.states[i];
 684                 if (!cx->valid)
 685                         continue;
 686
 687                 if (higher) {
 688                         cx->promotion.state = higher;
 689                         cx->promotion.threshold.ticks = cx->latency_ticks;
 690                         if (cx->type >= ACPI_STATE_C2)
 691                                 cx->promotion.threshold.count = 4;
 692                         else
 693                                 cx->promotion.threshold.count = 10;
 694                         if (higher->type == ACPI_STATE_C3)
 695                                 cx->promotion.threshold.bm = bm_history;
 696                 }
 697
 698                 higher = cx;
 699         }
 700
 701         return 0;
 702 }
 703
 704 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 705 {
 706
 707         if (!pr)
 708                 return -EINVAL;
 709
 710         if (!pr->pblk)
 711                 return -ENODEV;
 712
 713         /* if info is obtained from pblk/fadt, type equals state */
 714         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 715         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 716
 717 #ifndef CONFIG_HOTPLUG_CPU
 718         /*
 719          * Check for P_LVL2_UP flag before entering C2 and above on
 720          * an SMP system.
 721          */
 722         if ((num_online_cpus() > 1) &&
 723             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 724                 return -ENODEV;
 725 #endif
 726
 727         /* determine C2 and C3 address from pblk */
 728         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 729         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 730
 731         /* determine latencies from FADT */
 732         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency;
 733         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency;
 734
 735         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 736                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 737                           pr->power.states[ACPI_STATE_C2].address,
 738                           pr->power.states[ACPI_STATE_C3].address));
 739
 740         return 0;
 741 }
 742
 743 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 744 {
 745         if (!pr->power.states[ACPI_STATE_C1].valid) {
 746                 /* set the first C-State to C1 */
 747                 /* all processors need to support C1 */
 748                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 749                 pr->power.states[ACPI_STATE_C1].valid = 1;
 750         }
 751         /* the C0 state only exists as a filler in our array */
 752         pr->power.states[ACPI_STATE_C0].valid = 1;
 753         return 0;
 754 }
 755
 756 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 757 {
 758         acpi_status status = 0;
 759         acpi_integer count;
 760         int current_count;
 761         int i;
 762         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 763         union acpi_object *cst;
 764
 765
 766         if (nocst)
 767                 return -ENODEV;
 768
 769         current_count = 0;
 770
 771         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 772         if (ACPI_FAILURE(status)) {
 773                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 774                 return -ENODEV;
 775         }
 776
 777         cst = buffer.pointer;
 778
 779         /* There must be at least 2 elements */
 780         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 781                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 782                 status = -EFAULT;
 783                 goto end;
 784         }
 785
 786         count = cst->package.elements[0].integer.value;
 787
 788         /* Validate number of power states. */
 789         if (count < 1 || count != cst->package.count - 1) {
 790                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 791                 status = -EFAULT;
 792                 goto end;
 793         }
 794
 795         /* Tell driver that at least _CST is supported. */
 796         pr->flags.has_cst = 1;
 797
 798         for (i = 1; i <= count; i++) {
 799                 union acpi_object *element;
 800                 union acpi_object *obj;
 801                 struct acpi_power_register *reg;
 802                 struct acpi_processor_cx cx;
 803
 804                 memset(&cx, 0, sizeof(cx));
 805
 806                 element = &(cst->package.elements[i]);
 807                 if (element->type != ACPI_TYPE_PACKAGE)
 808                         continue;
 809
 810                 if (element->package.count != 4)
 811                         continue;
 812
 813                 obj = &(element->package.elements[0]);
 814
 815                 if (obj->type != ACPI_TYPE_BUFFER)
 816                         continue;
 817
 818                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 819
 820                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 821                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 822                         continue;
 823
 824                 /* There should be an easy way to extract an integer... */
 825                 obj = &(element->package.elements[1]);
 826                 if (obj->type != ACPI_TYPE_INTEGER)
 827                         continue;
 828
 829                 cx.type = obj->integer.value;
 830                 /*
 831                  * Some buggy BIOSes won't list C1 in _CST -
 832                  * Let acpi_processor_get_power_info_default() handle them later
 833                  */
 834                 if (i == 1 && cx.type != ACPI_STATE_C1)
 835                         current_count++;
 836
 837                 cx.address = reg->address;
 838                 cx.index = current_count + 1;
 839
 840                 cx.space_id = ACPI_CSTATE_SYSTEMIO;
 841                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 842                         if (acpi_processor_ffh_cstate_probe
 843                                         (pr->id, &cx, reg) == 0) {
 844                                 cx.space_id = ACPI_CSTATE_FFH;
 845                         } else if (cx.type != ACPI_STATE_C1) {
 846                                 /*
 847                                  * C1 is a special case where FIXED_HARDWARE
 848                                  * can be handled in non-MWAIT way as well.
 849                                  * In that case, save this _CST entry info.
 850                                  * That is, we retain space_id of SYSTEM_IO for
 851                                  * halt based C1.
 852                                  * Otherwise, ignore this info and continue.
 853                                  */
 854                                 continue;
 855                         }
 856                 }
 857
 858                 obj = &(element->package.elements[2]);
 859                 if (obj->type != ACPI_TYPE_INTEGER)
 860                         continue;
 861
 862                 cx.latency = obj->integer.value;
 863
 864                 obj = &(element->package.elements[3]);
 865                 if (obj->type != ACPI_TYPE_INTEGER)
 866                         continue;
 867
 868                 cx.power = obj->integer.value;
 869
 870                 current_count++;
 871                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 872
 873                 /*
 874                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 875                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 876                  */
 877                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 878                         printk(KERN_WARNING
 879                                "Limiting number of power states to max (%d)\n",
 880                                ACPI_PROCESSOR_MAX_POWER);
 881                         printk(KERN_WARNING
 882                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 883                         break;
 884                 }
 885         }
 886
 887         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 888                           current_count));
 889
 890         /* Validate number of power states discovered */
 891         if (current_count < 2)
 892                 status = -EFAULT;
 893
 894       end:
 895         kfree(buffer.pointer);
 896
 897         return status;
 898 }
 899
 900 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 901 {
 902
 903         if (!cx->address)
 904                 return;
 905
 906         /*
 907          * C2 latency must be less than or equal to 100
 908          * microseconds.
 909          */
 910         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 911                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 912                                   "latency too large [%d]\n", cx->latency));
 913                 return;
 914         }
 915
 916         /*
 917          * Otherwise we've met all of our C2 requirements.
 918          * Normalize the C2 latency to expidite policy
 919          */
 920         cx->valid = 1;
 921         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 922
 923         return;
 924 }
 925
 926 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 927                                            struct acpi_processor_cx *cx)
 928 {
 929         static int bm_check_flag;
 930
 931
 932         if (!cx->address)
 933                 return;
 934
 935         /*
 936          * C3 latency must be less than or equal to 1000
 937          * microseconds.
 938          */
 939         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 940                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 941                                   "latency too large [%d]\n", cx->latency));
 942                 return;
 943         }
 944
 945         /*
 946          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 947          * DMA transfers are used by any ISA device to avoid livelock.
 948          * Note that we could disable Type-F DMA (as recommended by
 949          * the erratum), but this is known to disrupt certain ISA
 950          * devices thus we take the conservative approach.
 951          */
 952         else if (errata.piix4.fdma) {
 953                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 954                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 955                 return;
 956         }
 957
 958         /* All the logic here assumes flags.bm_check is same across all CPUs */
 959         if (!bm_check_flag) {
 960                 /* Determine whether bm_check is needed based on CPU  */
 961                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 962                 bm_check_flag = pr->flags.bm_check;
 963         } else {
 964                 pr->flags.bm_check = bm_check_flag;
 965         }
 966
 967         if (pr->flags.bm_check) {
 968                 /* bus mastering control is necessary */
 969                 if (!pr->flags.bm_control) {
 970                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 971                                           "C3 support requires bus mastering control\n"));
 972                         return;
 973                 }
 974         } else {
 975                 /*
 976                  * WBINVD should be set in fadt, for C3 state to be
 977                  * supported on when bm_check is not required.
 978                  */
 979                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 980                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 981                                           "Cache invalidation should work properly"
 982                                           " for C3 to be enabled on SMP systems\n"));
 983                         return;
 984                 }
 985                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 986         }
 987
 988         /*
 989          * Otherwise we've met all of our C3 requirements.
 990          * Normalize the C3 latency to expidite policy.  Enable
 991          * checking of bus mastering status (bm_check) so we can
 992          * use this in our C3 policy
 993          */
 994         cx->valid = 1;
 995         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 996
 997         return;
 998 }
 999
1000 static int acpi_processor_power_verify(struct acpi_processor *pr)
1001 {
1002         unsigned int i;
1003         unsigned int working = 0;
1004
1005         pr->power.timer_broadcast_on_state = INT_MAX;
1006
1007         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1008                 struct acpi_processor_cx *cx = &pr->power.states[i];
1009
1010                 switch (cx->type) {
1011                 case ACPI_STATE_C1:
1012                         cx->valid = 1;
1013                         break;
1014
1015                 case ACPI_STATE_C2:
1016                         acpi_processor_power_verify_c2(cx);
1017                         if (cx->valid)
1018                                 acpi_timer_check_state(i, pr, cx);
1019                         break;
1020
1021                 case ACPI_STATE_C3:
1022                         acpi_processor_power_verify_c3(pr, cx);
1023                         if (cx->valid)
1024                                 acpi_timer_check_state(i, pr, cx);
1025                         break;
1026                 }
1027
1028                 if (cx->valid)
1029                         working++;
1030         }
1031
1032         acpi_propagate_timer_broadcast(pr);
1033
1034         return (working);
1035 }
1036
1037 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1038 {
1039         unsigned int i;
1040         int result;
1041
1042
1043         /* NOTE: the idle thread may not be running while calling
1044          * this function */
1045
1046         /* Zero initialize all the C-states info. */
1047         memset(pr->power.states, 0, sizeof(pr->power.states));
1048
1049         result = acpi_processor_get_power_info_cst(pr);
1050         if (result == -ENODEV)
1051                 result = acpi_processor_get_power_info_fadt(pr);
1052
1053         if (result)
1054                 return result;
1055
1056         acpi_processor_get_power_info_default(pr);
1057
1058         pr->power.count = acpi_processor_power_verify(pr);
1059
1060         /*
1061          * Set Default Policy
1062          * ------------------
1063          * Now that we know which states are supported, set the default
1064          * policy.  Note that this policy can be changed dynamically
1065          * (e.g. encourage deeper sleeps to conserve battery life when
1066          * not on AC).
1067          */
1068         result = acpi_processor_set_power_policy(pr);
1069         if (result)
1070                 return result;
1071
1072         /*
1073          * if one state of type C2 or C3 is available, mark this
1074          * CPU as being "idle manageable"
1075          */
1076         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1077                 if (pr->power.states[i].valid) {
1078                         pr->power.count = i;
1079                         if (pr->power.states[i].type >= ACPI_STATE_C2)
1080                                 pr->flags.power = 1;
1081                 }
1082         }
1083
1084         return 0;
1085 }
1086
1087 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1088 {
1089         int result = 0;
1090
1091
1092         if (!pr)
1093                 return -EINVAL;
1094
1095         if (nocst) {
1096                 return -ENODEV;
1097         }
1098
1099         if (!pr->flags.power_setup_done)
1100                 return -ENODEV;
1101
1102         /* Fall back to the default idle loop */
1103         pm_idle = pm_idle_save;
1104         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
1105
1106         pr->flags.power = 0;
1107         result = acpi_processor_get_power_info(pr);
1108         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1109                 pm_idle = acpi_processor_idle;
1110
1111         return result;
1112 }
1113
1114 /* proc interface */
1115
1116 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1117 {
1118         struct acpi_processor *pr = seq->private;
1119         unsigned int i;
1120
1121
1122         if (!pr)
1123                 goto end;
1124
1125         seq_printf(seq, "active state:            C%zd\n"
1126                    "max_cstate:              C%d\n"
1127                    "bus master activity:     %08x\n"
1128                    "maximum allowed latency: %d usec\n",
1129                    pr->power.state ? pr->power.state - pr->power.states : 0,
1130                    max_cstate, (unsigned)pr->power.bm_activity,
1131                    system_latency_constraint());
1132
1133         seq_puts(seq, "states:\n");
1134
1135         for (i = 1; i <= pr->power.count; i++) {
1136                 seq_printf(seq, "   %cC%d:                  ",
1137                            (&pr->power.states[i] ==
1138                             pr->power.state ? '*' : ' '), i);
1139
1140                 if (!pr->power.states[i].valid) {
1141                         seq_puts(seq, "<not supported>\n");
1142                         continue;
1143                 }
1144
1145                 switch (pr->power.states[i].type) {
1146                 case ACPI_STATE_C1:
1147                         seq_printf(seq, "type[C1] ");
1148                         break;
1149                 case ACPI_STATE_C2:
1150                         seq_printf(seq, "type[C2] ");
1151                         break;
1152                 case ACPI_STATE_C3:
1153                         seq_printf(seq, "type[C3] ");
1154                         break;
1155                 default:
1156                         seq_printf(seq, "type[--] ");
1157                         break;
1158                 }
1159
1160                 if (pr->power.states[i].promotion.state)
1161                         seq_printf(seq, "promotion[C%zd] ",
1162                                    (pr->power.states[i].promotion.state -
1163                                     pr->power.states));
1164                 else
1165                         seq_puts(seq, "promotion[--] ");
1166
1167                 if (pr->power.states[i].demotion.state)
1168                         seq_printf(seq, "demotion[C%zd] ",
1169                                    (pr->power.states[i].demotion.state -
1170                                     pr->power.states));
1171                 else
1172                         seq_puts(seq, "demotion[--] ");
1173
1174                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1175                            pr->power.states[i].latency,
1176                            pr->power.states[i].usage,
1177                            (unsigned long long)pr->power.states[i].time);
1178         }
1179
1180       end:
1181         return 0;
1182 }
1183
1184 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1185 {
1186         return single_open(file, acpi_processor_power_seq_show,
1187                            PDE(inode)->data);
1188 }
1189
1190 static const struct file_operations acpi_processor_power_fops = {
1191         .open = acpi_processor_power_open_fs,
1192         .read = seq_read,
1193         .llseek = seq_lseek,
1194         .release = single_release,
1195 };
1196
1197 #ifdef CONFIG_SMP
1198 static void smp_callback(void *v)
1199 {
1200         /* we already woke the CPU up, nothing more to do */
1201 }
1202
1203 /*
1204  * This function gets called when a part of the kernel has a new latency
1205  * requirement.  This means we need to get all processors out of their C-state,
1206  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1207  * wakes them all right up.
1208  */
1209 static int acpi_processor_latency_notify(struct notifier_block *b,
1210                 unsigned long l, void *v)
1211 {
1212         smp_call_function(smp_callback, NULL, 0, 1);
1213         return NOTIFY_OK;
1214 }
1215
1216 static struct notifier_block acpi_processor_latency_notifier = {
1217         .notifier_call = acpi_processor_latency_notify,
1218 };
1219 #endif
1220
1221 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1222                               struct acpi_device *device)
1223 {
1224         acpi_status status = 0;
1225         static int first_run;
1226         struct proc_dir_entry *entry = NULL;
1227         unsigned int i;
1228
1229
1230         if (!first_run) {
1231                 dmi_check_system(processor_power_dmi_table);
1232                 if (max_cstate < ACPI_C_STATES_MAX)
1233                         printk(KERN_NOTICE
1234                                "ACPI: processor limited to max C-state %d\n",
1235                                max_cstate);
1236                 first_run++;
1237 #ifdef CONFIG_SMP
1238                 register_latency_notifier(&acpi_processor_latency_notifier);
1239 #endif
1240         }
1241
1242         if (!pr)
1243                 return -EINVAL;
1244
1245         if (acpi_gbl_FADT.cst_control && !nocst) {
1246                 status =
1247                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1248                 if (ACPI_FAILURE(status)) {
1249                         ACPI_EXCEPTION((AE_INFO, status,
1250                                         "Notifying BIOS of _CST ability failed"));
1251                 }
1252         }
1253
1254         acpi_processor_get_power_info(pr);
1255
1256         /*
1257          * Install the idle handler if processor power management is supported.
1258          * Note that we use previously set idle handler will be used on
1259          * platforms that only support C1.
1260          */
1261         if ((pr->flags.power) && (!boot_option_idle_override)) {
1262                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1263                 for (i = 1; i <= pr->power.count; i++)
1264                         if (pr->power.states[i].valid)
1265                                 printk(" C%d[C%d]", i,
1266                                        pr->power.states[i].type);
1267                 printk(")\n");
1268
1269                 if (pr->id == 0) {
1270                         pm_idle_save = pm_idle;
1271                         pm_idle = acpi_processor_idle;
1272                 }
1273         }
1274
1275         /* 'power' [R] */
1276         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1277                                   S_IRUGO, acpi_device_dir(device));
1278         if (!entry)
1279                 return -EIO;
1280         else {
1281                 entry->proc_fops = &acpi_processor_power_fops;
1282                 entry->data = acpi_driver_data(device);
1283                 entry->owner = THIS_MODULE;
1284         }
1285
1286         pr->flags.power_setup_done = 1;
1287
1288         return 0;
1289 }
1290
1291 int acpi_processor_power_exit(struct acpi_processor *pr,
1292                               struct acpi_device *device)
1293 {
1294
1295         pr->flags.power_setup_done = 0;
1296
1297         if (acpi_device_dir(device))
1298                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1299                                   acpi_device_dir(device));
1300
1301         /* Unregister the idle handler when processor #0 is removed. */
1302         if (pr->id == 0) {
1303                 pm_idle = pm_idle_save;
1304
1305                 /*
1306                  * We are about to unload the current idle thread pm callback
1307                  * (pm_idle), Wait for all processors to update cached/local
1308                  * copies of pm_idle before proceeding.
1309                  */
1310                 cpu_idle_wait();
1311 #ifdef CONFIG_SMP
1312                 unregister_latency_notifier(&acpi_processor_latency_notifier);
1313 #endif
1314         }
1315
1316         return 0;
1317 }