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
  42 #include <asm/io.h>
  43 #include <asm/uaccess.h>
  44
  45 #include <acpi/acpi_bus.h>
  46 #include <acpi/processor.h>
  47
  48 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  49 #define ACPI_PROCESSOR_CLASS            "processor"
  50 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
  51 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  52 ACPI_MODULE_NAME("acpi_processor")
  53 #define ACPI_PROCESSOR_FILE_POWER       "power"
  54 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  55 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  56 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  57 static void (*pm_idle_save) (void) __read_mostly;
  58 module_param(max_cstate, uint, 0644);
  59
  60 static unsigned int nocst __read_mostly;
  61 module_param(nocst, uint, 0000);
  62
  63 /*
  64  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  65  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  66  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  67  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  68  * reduce history for more aggressive entry into C3
  69  */
  70 static unsigned int bm_history __read_mostly =
  71     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  72 module_param(bm_history, uint, 0644);
  73 /* --------------------------------------------------------------------------
  74                                 Power Management
  75    -------------------------------------------------------------------------- */
  76
  77 /*
  78  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  79  * For now disable this. Probably a bug somewhere else.
  80  *
  81  * To skip this limit, boot/load with a large max_cstate limit.
  82  */
  83 static int set_max_cstate(struct dmi_system_id *id)
  84 {
  85         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  86                 return 0;
  87
  88         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
  89                " Override with \"processor.max_cstate=%d\"\n", id->ident,
  90                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  91
  92         max_cstate = (long)id->driver_data;
  93
  94         return 0;
  95 }
  96
  97 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
  98    callers to only run once -AK */
  99 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 100         { set_max_cstate, "IBM ThinkPad R40e", {
 101           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 102           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 103         { set_max_cstate, "IBM ThinkPad R40e", {
 104           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 105           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 106         { set_max_cstate, "IBM ThinkPad R40e", {
 107           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 108           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 109         { set_max_cstate, "IBM ThinkPad R40e", {
 110           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 111           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 112         { set_max_cstate, "IBM ThinkPad R40e", {
 113           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 114           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 115         { set_max_cstate, "IBM ThinkPad R40e", {
 116           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 117           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 118         { set_max_cstate, "IBM ThinkPad R40e", {
 119           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 120           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 121         { set_max_cstate, "IBM ThinkPad R40e", {
 122           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 123           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 124         { set_max_cstate, "IBM ThinkPad R40e", {
 125           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 126           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 127         { set_max_cstate, "IBM ThinkPad R40e", {
 128           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 129           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 130         { set_max_cstate, "IBM ThinkPad R40e", {
 131           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 132           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 133         { set_max_cstate, "IBM ThinkPad R40e", {
 134           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 135           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 136         { set_max_cstate, "IBM ThinkPad R40e", {
 137           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 138           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 139         { set_max_cstate, "IBM ThinkPad R40e", {
 140           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 141           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 142         { set_max_cstate, "IBM ThinkPad R40e", {
 143           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 144           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 145         { set_max_cstate, "IBM ThinkPad R40e", {
 146           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 147           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 148         { set_max_cstate, "Medion 41700", {
 149           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 150           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 151         { set_max_cstate, "Clevo 5600D", {
 152           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 153           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 154          (void *)2},
 155         {},
 156 };
 157
 158 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 159 {
 160         if (t2 >= t1)
 161                 return (t2 - t1);
 162         else if (!acpi_fadt.tmr_val_ext)
 163                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 164         else
 165                 return ((0xFFFFFFFF - t1) + t2);
 166 }
 167
 168 static void
 169 acpi_processor_power_activate(struct acpi_processor *pr,
 170                               struct acpi_processor_cx *new)
 171 {
 172         struct acpi_processor_cx *old;
 173
 174         if (!pr || !new)
 175                 return;
 176
 177         old = pr->power.state;
 178
 179         if (old)
 180                 old->promotion.count = 0;
 181         new->demotion.count = 0;
 182
 183         /* Cleanup from old state. */
 184         if (old) {
 185                 switch (old->type) {
 186                 case ACPI_STATE_C3:
 187                         /* Disable bus master reload */
 188                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 189                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
 190                                                   ACPI_MTX_DO_NOT_LOCK);
 191                         break;
 192                 }
 193         }
 194
 195         /* Prepare to use new state. */
 196         switch (new->type) {
 197         case ACPI_STATE_C3:
 198                 /* Enable bus master reload */
 199                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 200                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
 201                                           ACPI_MTX_DO_NOT_LOCK);
 202                 break;
 203         }
 204
 205         pr->power.state = new;
 206
 207         return;
 208 }
 209
 210 static void acpi_safe_halt(void)
 211 {
 212         current_thread_info()->status &= ~TS_POLLING;
 213         smp_mb__after_clear_bit();
 214         if (!need_resched())
 215                 safe_halt();
 216         current_thread_info()->status |= TS_POLLING;
 217 }
 218
 219 static atomic_t c3_cpu_count;
 220
 221 static void acpi_processor_idle(void)
 222 {
 223         struct acpi_processor *pr = NULL;
 224         struct acpi_processor_cx *cx = NULL;
 225         struct acpi_processor_cx *next_state = NULL;
 226         int sleep_ticks = 0;
 227         u32 t1, t2 = 0;
 228
 229         pr = processors[smp_processor_id()];
 230         if (!pr)
 231                 return;
 232
 233         /*
 234          * Interrupts must be disabled during bus mastering calculations and
 235          * for C2/C3 transitions.
 236          */
 237         local_irq_disable();
 238
 239         /*
 240          * Check whether we truly need to go idle, or should
 241          * reschedule:
 242          */
 243         if (unlikely(need_resched())) {
 244                 local_irq_enable();
 245                 return;
 246         }
 247
 248         cx = pr->power.state;
 249         if (!cx) {
 250                 if (pm_idle_save)
 251                         pm_idle_save();
 252                 else
 253                         acpi_safe_halt();
 254                 return;
 255         }
 256
 257         /*
 258          * Check BM Activity
 259          * -----------------
 260          * Check for bus mastering activity (if required), record, and check
 261          * for demotion.
 262          */
 263         if (pr->flags.bm_check) {
 264                 u32 bm_status = 0;
 265                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 266
 267                 if (diff > 31)
 268                         diff = 31;
 269
 270                 pr->power.bm_activity <<= diff;
 271
 272                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 273                                   &bm_status, ACPI_MTX_DO_NOT_LOCK);
 274                 if (bm_status) {
 275                         pr->power.bm_activity |= 0x1;
 276                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 277                                           1, ACPI_MTX_DO_NOT_LOCK);
 278                 }
 279                 /*
 280                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 281                  * the true state of bus mastering activity; forcing us to
 282                  * manually check the BMIDEA bit of each IDE channel.
 283                  */
 284                 else if (errata.piix4.bmisx) {
 285                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 286                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 287                                 pr->power.bm_activity |= 0x1;
 288                 }
 289
 290                 pr->power.bm_check_timestamp = jiffies;
 291
 292                 /*
 293                  * If bus mastering is or was active this jiffy, demote
 294                  * to avoid a faulty transition.  Note that the processor
 295                  * won't enter a low-power state during this call (to this
 296                  * function) but should upon the next.
 297                  *
 298                  * TBD: A better policy might be to fallback to the demotion
 299                  *      state (use it for this quantum only) istead of
 300                  *      demoting -- and rely on duration as our sole demotion
 301                  *      qualification.  This may, however, introduce DMA
 302                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 303                  */
 304                 if ((pr->power.bm_activity & 0x1) &&
 305                     cx->demotion.threshold.bm) {
 306                         local_irq_enable();
 307                         next_state = cx->demotion.state;
 308                         goto end;
 309                 }
 310         }
 311
 312 #ifdef CONFIG_HOTPLUG_CPU
 313         /*
 314          * Check for P_LVL2_UP flag before entering C2 and above on
 315          * an SMP system. We do it here instead of doing it at _CST/P_LVL
 316          * detection phase, to work cleanly with logical CPU hotplug.
 317          */
 318         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 319             !pr->flags.has_cst && !acpi_fadt.plvl2_up)
 320                 cx = &pr->power.states[ACPI_STATE_C1];
 321 #endif
 322
 323         /*
 324          * Sleep:
 325          * ------
 326          * Invoke the current Cx state to put the processor to sleep.
 327          */
 328         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 329                 current_thread_info()->status &= ~TS_POLLING;
 330                 smp_mb__after_clear_bit();
 331                 if (need_resched()) {
 332                         current_thread_info()->status |= TS_POLLING;
 333                         local_irq_enable();
 334                         return;
 335                 }
 336         }
 337
 338         switch (cx->type) {
 339
 340         case ACPI_STATE_C1:
 341                 /*
 342                  * Invoke C1.
 343                  * Use the appropriate idle routine, the one that would
 344                  * be used without acpi C-states.
 345                  */
 346                 if (pm_idle_save)
 347                         pm_idle_save();
 348                 else
 349                         acpi_safe_halt();
 350
 351                 /*
 352                  * TBD: Can't get time duration while in C1, as resumes
 353                  *      go to an ISR rather than here.  Need to instrument
 354                  *      base interrupt handler.
 355                  */
 356                 sleep_ticks = 0xFFFFFFFF;
 357                 break;
 358
 359         case ACPI_STATE_C2:
 360                 /* Get start time (ticks) */
 361                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 362                 /* Invoke C2 */
 363                 inb(cx->address);
 364                 /* Dummy wait op - must do something useless after P_LVL2 read
 365                    because chipsets cannot guarantee that STPCLK# signal
 366                    gets asserted in time to freeze execution properly. */
 367                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 368                 /* Get end time (ticks) */
 369                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 370
 371 #ifdef CONFIG_GENERIC_TIME
 372                 /* TSC halts in C2, so notify users */
 373                 mark_tsc_unstable();
 374 #endif
 375                 /* Re-enable interrupts */
 376                 local_irq_enable();
 377                 current_thread_info()->status |= TS_POLLING;
 378                 /* Compute time (ticks) that we were actually asleep */
 379                 sleep_ticks =
 380                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 381                 break;
 382
 383         case ACPI_STATE_C3:
 384
 385                 if (pr->flags.bm_check) {
 386                         if (atomic_inc_return(&c3_cpu_count) ==
 387                             num_online_cpus()) {
 388                                 /*
 389                                  * All CPUs are trying to go to C3
 390                                  * Disable bus master arbitration
 391                                  */
 392                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
 393                                                   ACPI_MTX_DO_NOT_LOCK);
 394                         }
 395                 } else {
 396                         /* SMP with no shared cache... Invalidate cache  */
 397                         ACPI_FLUSH_CPU_CACHE();
 398                 }
 399
 400                 /* Get start time (ticks) */
 401                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 402                 /* Invoke C3 */
 403                 inb(cx->address);
 404                 /* Dummy wait op (see above) */
 405                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 406                 /* Get end time (ticks) */
 407                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 408                 if (pr->flags.bm_check) {
 409                         /* Enable bus master arbitration */
 410                         atomic_dec(&c3_cpu_count);
 411                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
 412                                           ACPI_MTX_DO_NOT_LOCK);
 413                 }
 414
 415 #ifdef CONFIG_GENERIC_TIME
 416                 /* TSC halts in C3, so notify users */
 417                 mark_tsc_unstable();
 418 #endif
 419                 /* Re-enable interrupts */
 420                 local_irq_enable();
 421                 current_thread_info()->status |= TS_POLLING;
 422                 /* Compute time (ticks) that we were actually asleep */
 423                 sleep_ticks =
 424                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 425                 break;
 426
 427         default:
 428                 local_irq_enable();
 429                 return;
 430         }
 431         cx->usage++;
 432         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 433                 cx->time += sleep_ticks;
 434
 435         next_state = pr->power.state;
 436
 437 #ifdef CONFIG_HOTPLUG_CPU
 438         /* Don't do promotion/demotion */
 439         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 440             !pr->flags.has_cst && !acpi_fadt.plvl2_up) {
 441                 next_state = cx;
 442                 goto end;
 443         }
 444 #endif
 445
 446         /*
 447          * Promotion?
 448          * ----------
 449          * Track the number of longs (time asleep is greater than threshold)
 450          * and promote when the count threshold is reached.  Note that bus
 451          * mastering activity may prevent promotions.
 452          * Do not promote above max_cstate.
 453          */
 454         if (cx->promotion.state &&
 455             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 456                 if (sleep_ticks > cx->promotion.threshold.ticks) {
 457                         cx->promotion.count++;
 458                         cx->demotion.count = 0;
 459                         if (cx->promotion.count >=
 460                             cx->promotion.threshold.count) {
 461                                 if (pr->flags.bm_check) {
 462                                         if (!
 463                                             (pr->power.bm_activity & cx->
 464                                              promotion.threshold.bm)) {
 465                                                 next_state =
 466                                                     cx->promotion.state;
 467                                                 goto end;
 468                                         }
 469                                 } else {
 470                                         next_state = cx->promotion.state;
 471                                         goto end;
 472                                 }
 473                         }
 474                 }
 475         }
 476
 477         /*
 478          * Demotion?
 479          * ---------
 480          * Track the number of shorts (time asleep is less than time threshold)
 481          * and demote when the usage threshold is reached.
 482          */
 483         if (cx->demotion.state) {
 484                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 485                         cx->demotion.count++;
 486                         cx->promotion.count = 0;
 487                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 488                                 next_state = cx->demotion.state;
 489                                 goto end;
 490                         }
 491                 }
 492         }
 493
 494       end:
 495         /*
 496          * Demote if current state exceeds max_cstate
 497          */
 498         if ((pr->power.state - pr->power.states) > max_cstate) {
 499                 if (cx->demotion.state)
 500                         next_state = cx->demotion.state;
 501         }
 502
 503         /*
 504          * New Cx State?
 505          * -------------
 506          * If we're going to start using a new Cx state we must clean up
 507          * from the previous and prepare to use the new.
 508          */
 509         if (next_state != pr->power.state)
 510                 acpi_processor_power_activate(pr, next_state);
 511 }
 512
 513 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 514 {
 515         unsigned int i;
 516         unsigned int state_is_set = 0;
 517         struct acpi_processor_cx *lower = NULL;
 518         struct acpi_processor_cx *higher = NULL;
 519         struct acpi_processor_cx *cx;
 520
 521
 522         if (!pr)
 523                 return -EINVAL;
 524
 525         /*
 526          * This function sets the default Cx state policy (OS idle handler).
 527          * Our scheme is to promote quickly to C2 but more conservatively
 528          * to C3.  We're favoring C2  for its characteristics of low latency
 529          * (quick response), good power savings, and ability to allow bus
 530          * mastering activity.  Note that the Cx state policy is completely
 531          * customizable and can be altered dynamically.
 532          */
 533
 534         /* startup state */
 535         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 536                 cx = &pr->power.states[i];
 537                 if (!cx->valid)
 538                         continue;
 539
 540                 if (!state_is_set)
 541                         pr->power.state = cx;
 542                 state_is_set++;
 543                 break;
 544         }
 545
 546         if (!state_is_set)
 547                 return -ENODEV;
 548
 549         /* demotion */
 550         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 551                 cx = &pr->power.states[i];
 552                 if (!cx->valid)
 553                         continue;
 554
 555                 if (lower) {
 556                         cx->demotion.state = lower;
 557                         cx->demotion.threshold.ticks = cx->latency_ticks;
 558                         cx->demotion.threshold.count = 1;
 559                         if (cx->type == ACPI_STATE_C3)
 560                                 cx->demotion.threshold.bm = bm_history;
 561                 }
 562
 563                 lower = cx;
 564         }
 565
 566         /* promotion */
 567         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 568                 cx = &pr->power.states[i];
 569                 if (!cx->valid)
 570                         continue;
 571
 572                 if (higher) {
 573                         cx->promotion.state = higher;
 574                         cx->promotion.threshold.ticks = cx->latency_ticks;
 575                         if (cx->type >= ACPI_STATE_C2)
 576                                 cx->promotion.threshold.count = 4;
 577                         else
 578                                 cx->promotion.threshold.count = 10;
 579                         if (higher->type == ACPI_STATE_C3)
 580                                 cx->promotion.threshold.bm = bm_history;
 581                 }
 582
 583                 higher = cx;
 584         }
 585
 586         return 0;
 587 }
 588
 589 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 590 {
 591
 592         if (!pr)
 593                 return -EINVAL;
 594
 595         if (!pr->pblk)
 596                 return -ENODEV;
 597
 598         /* if info is obtained from pblk/fadt, type equals state */
 599         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 600         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 601
 602 #ifndef CONFIG_HOTPLUG_CPU
 603         /*
 604          * Check for P_LVL2_UP flag before entering C2 and above on
 605          * an SMP system.
 606          */
 607         if ((num_online_cpus() > 1) && !acpi_fadt.plvl2_up)
 608                 return -ENODEV;
 609 #endif
 610
 611         /* determine C2 and C3 address from pblk */
 612         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 613         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 614
 615         /* determine latencies from FADT */
 616         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 617         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 618
 619         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 620                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 621                           pr->power.states[ACPI_STATE_C2].address,
 622                           pr->power.states[ACPI_STATE_C3].address));
 623
 624         return 0;
 625 }
 626
 627 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
 628 {
 629
 630         /* Zero initialize all the C-states info. */
 631         memset(pr->power.states, 0, sizeof(pr->power.states));
 632
 633         /* set the first C-State to C1 */
 634         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 635
 636         /* the C0 state only exists as a filler in our array,
 637          * and all processors need to support C1 */
 638         pr->power.states[ACPI_STATE_C0].valid = 1;
 639         pr->power.states[ACPI_STATE_C1].valid = 1;
 640
 641         return 0;
 642 }
 643
 644 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 645 {
 646         acpi_status status = 0;
 647         acpi_integer count;
 648         int current_count;
 649         int i;
 650         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 651         union acpi_object *cst;
 652
 653
 654         if (nocst)
 655                 return -ENODEV;
 656
 657         current_count = 1;
 658
 659         /* Zero initialize C2 onwards and prepare for fresh CST lookup */
 660         for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++)
 661                 memset(&(pr->power.states[i]), 0,
 662                                 sizeof(struct acpi_processor_cx));
 663
 664         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 665         if (ACPI_FAILURE(status)) {
 666                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 667                 return -ENODEV;
 668         }
 669
 670         cst = (union acpi_object *)buffer.pointer;
 671
 672         /* There must be at least 2 elements */
 673         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 674                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 675                 status = -EFAULT;
 676                 goto end;
 677         }
 678
 679         count = cst->package.elements[0].integer.value;
 680
 681         /* Validate number of power states. */
 682         if (count < 1 || count != cst->package.count - 1) {
 683                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 684                 status = -EFAULT;
 685                 goto end;
 686         }
 687
 688         /* Tell driver that at least _CST is supported. */
 689         pr->flags.has_cst = 1;
 690
 691         for (i = 1; i <= count; i++) {
 692                 union acpi_object *element;
 693                 union acpi_object *obj;
 694                 struct acpi_power_register *reg;
 695                 struct acpi_processor_cx cx;
 696
 697                 memset(&cx, 0, sizeof(cx));
 698
 699                 element = (union acpi_object *)&(cst->package.elements[i]);
 700                 if (element->type != ACPI_TYPE_PACKAGE)
 701                         continue;
 702
 703                 if (element->package.count != 4)
 704                         continue;
 705
 706                 obj = (union acpi_object *)&(element->package.elements[0]);
 707
 708                 if (obj->type != ACPI_TYPE_BUFFER)
 709                         continue;
 710
 711                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 712
 713                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 714                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 715                         continue;
 716
 717                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
 718                     0 : reg->address;
 719
 720                 /* There should be an easy way to extract an integer... */
 721                 obj = (union acpi_object *)&(element->package.elements[1]);
 722                 if (obj->type != ACPI_TYPE_INTEGER)
 723                         continue;
 724
 725                 cx.type = obj->integer.value;
 726
 727                 if ((cx.type != ACPI_STATE_C1) &&
 728                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
 729                         continue;
 730
 731                 if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
 732                         continue;
 733
 734                 obj = (union acpi_object *)&(element->package.elements[2]);
 735                 if (obj->type != ACPI_TYPE_INTEGER)
 736                         continue;
 737
 738                 cx.latency = obj->integer.value;
 739
 740                 obj = (union acpi_object *)&(element->package.elements[3]);
 741                 if (obj->type != ACPI_TYPE_INTEGER)
 742                         continue;
 743
 744                 cx.power = obj->integer.value;
 745
 746                 current_count++;
 747                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 748
 749                 /*
 750                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 751                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 752                  */
 753                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 754                         printk(KERN_WARNING
 755                                "Limiting number of power states to max (%d)\n",
 756                                ACPI_PROCESSOR_MAX_POWER);
 757                         printk(KERN_WARNING
 758                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 759                         break;
 760                 }
 761         }
 762
 763         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 764                           current_count));
 765
 766         /* Validate number of power states discovered */
 767         if (current_count < 2)
 768                 status = -EFAULT;
 769
 770       end:
 771         acpi_os_free(buffer.pointer);
 772
 773         return status;
 774 }
 775
 776 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 777 {
 778
 779         if (!cx->address)
 780                 return;
 781
 782         /*
 783          * C2 latency must be less than or equal to 100
 784          * microseconds.
 785          */
 786         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 787                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 788                                   "latency too large [%d]\n", cx->latency));
 789                 return;
 790         }
 791
 792         /*
 793          * Otherwise we've met all of our C2 requirements.
 794          * Normalize the C2 latency to expidite policy
 795          */
 796         cx->valid = 1;
 797         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 798
 799         return;
 800 }
 801
 802 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 803                                            struct acpi_processor_cx *cx)
 804 {
 805         static int bm_check_flag;
 806
 807
 808         if (!cx->address)
 809                 return;
 810
 811         /*
 812          * C3 latency must be less than or equal to 1000
 813          * microseconds.
 814          */
 815         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 816                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 817                                   "latency too large [%d]\n", cx->latency));
 818                 return;
 819         }
 820
 821         /*
 822          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 823          * DMA transfers are used by any ISA device to avoid livelock.
 824          * Note that we could disable Type-F DMA (as recommended by
 825          * the erratum), but this is known to disrupt certain ISA
 826          * devices thus we take the conservative approach.
 827          */
 828         else if (errata.piix4.fdma) {
 829                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 830                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 831                 return;
 832         }
 833
 834         /* All the logic here assumes flags.bm_check is same across all CPUs */
 835         if (!bm_check_flag) {
 836                 /* Determine whether bm_check is needed based on CPU  */
 837                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 838                 bm_check_flag = pr->flags.bm_check;
 839         } else {
 840                 pr->flags.bm_check = bm_check_flag;
 841         }
 842
 843         if (pr->flags.bm_check) {
 844                 /* bus mastering control is necessary */
 845                 if (!pr->flags.bm_control) {
 846                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 847                                           "C3 support requires bus mastering control\n"));
 848                         return;
 849                 }
 850         } else {
 851                 /*
 852                  * WBINVD should be set in fadt, for C3 state to be
 853                  * supported on when bm_check is not required.
 854                  */
 855                 if (acpi_fadt.wb_invd != 1) {
 856                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 857                                           "Cache invalidation should work properly"
 858                                           " for C3 to be enabled on SMP systems\n"));
 859                         return;
 860                 }
 861                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
 862                                   0, ACPI_MTX_DO_NOT_LOCK);
 863         }
 864
 865         /*
 866          * Otherwise we've met all of our C3 requirements.
 867          * Normalize the C3 latency to expidite policy.  Enable
 868          * checking of bus mastering status (bm_check) so we can
 869          * use this in our C3 policy
 870          */
 871         cx->valid = 1;
 872         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 873
 874         return;
 875 }
 876
 877 static int acpi_processor_power_verify(struct acpi_processor *pr)
 878 {
 879         unsigned int i;
 880         unsigned int working = 0;
 881
 882 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 883         int timer_broadcast = 0;
 884         cpumask_t mask = cpumask_of_cpu(pr->id);
 885         on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
 886 #endif
 887
 888         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 889                 struct acpi_processor_cx *cx = &pr->power.states[i];
 890
 891                 switch (cx->type) {
 892                 case ACPI_STATE_C1:
 893                         cx->valid = 1;
 894                         break;
 895
 896                 case ACPI_STATE_C2:
 897                         acpi_processor_power_verify_c2(cx);
 898 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 899                         /* Some AMD systems fake C3 as C2, but still
 900                            have timer troubles */
 901                         if (cx->valid &&
 902                                 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
 903                                 timer_broadcast++;
 904 #endif
 905                         break;
 906
 907                 case ACPI_STATE_C3:
 908                         acpi_processor_power_verify_c3(pr, cx);
 909 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 910                         if (cx->valid)
 911                                 timer_broadcast++;
 912 #endif
 913                         break;
 914                 }
 915
 916                 if (cx->valid)
 917                         working++;
 918         }
 919
 920 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 921         if (timer_broadcast)
 922                 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
 923 #endif
 924
 925         return (working);
 926 }
 927
 928 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 929 {
 930         unsigned int i;
 931         int result;
 932
 933
 934         /* NOTE: the idle thread may not be running while calling
 935          * this function */
 936
 937         /* Adding C1 state */
 938         acpi_processor_get_power_info_default_c1(pr);
 939         result = acpi_processor_get_power_info_cst(pr);
 940         if (result == -ENODEV)
 941                 acpi_processor_get_power_info_fadt(pr);
 942
 943         pr->power.count = acpi_processor_power_verify(pr);
 944
 945         /*
 946          * Set Default Policy
 947          * ------------------
 948          * Now that we know which states are supported, set the default
 949          * policy.  Note that this policy can be changed dynamically
 950          * (e.g. encourage deeper sleeps to conserve battery life when
 951          * not on AC).
 952          */
 953         result = acpi_processor_set_power_policy(pr);
 954         if (result)
 955                 return result;
 956
 957         /*
 958          * if one state of type C2 or C3 is available, mark this
 959          * CPU as being "idle manageable"
 960          */
 961         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 962                 if (pr->power.states[i].valid) {
 963                         pr->power.count = i;
 964                         if (pr->power.states[i].type >= ACPI_STATE_C2)
 965                                 pr->flags.power = 1;
 966                 }
 967         }
 968
 969         return 0;
 970 }
 971
 972 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 973 {
 974         int result = 0;
 975
 976
 977         if (!pr)
 978                 return -EINVAL;
 979
 980         if (nocst) {
 981                 return -ENODEV;
 982         }
 983
 984         if (!pr->flags.power_setup_done)
 985                 return -ENODEV;
 986
 987         /* Fall back to the default idle loop */
 988         pm_idle = pm_idle_save;
 989         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
 990
 991         pr->flags.power = 0;
 992         result = acpi_processor_get_power_info(pr);
 993         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
 994                 pm_idle = acpi_processor_idle;
 995
 996         return result;
 997 }
 998
 999 /* proc interface */
1000
1001 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1002 {
1003         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
1004         unsigned int i;
1005
1006
1007         if (!pr)
1008                 goto end;
1009
1010         seq_printf(seq, "active state:            C%zd\n"
1011                    "max_cstate:              C%d\n"
1012                    "bus master activity:     %08x\n",
1013                    pr->power.state ? pr->power.state - pr->power.states : 0,
1014                    max_cstate, (unsigned)pr->power.bm_activity);
1015
1016         seq_puts(seq, "states:\n");
1017
1018         for (i = 1; i <= pr->power.count; i++) {
1019                 seq_printf(seq, "   %cC%d:                  ",
1020                            (&pr->power.states[i] ==
1021                             pr->power.state ? '*' : ' '), i);
1022
1023                 if (!pr->power.states[i].valid) {
1024                         seq_puts(seq, "<not supported>\n");
1025                         continue;
1026                 }
1027
1028                 switch (pr->power.states[i].type) {
1029                 case ACPI_STATE_C1:
1030                         seq_printf(seq, "type[C1] ");
1031                         break;
1032                 case ACPI_STATE_C2:
1033                         seq_printf(seq, "type[C2] ");
1034                         break;
1035                 case ACPI_STATE_C3:
1036                         seq_printf(seq, "type[C3] ");
1037                         break;
1038                 default:
1039                         seq_printf(seq, "type[--] ");
1040                         break;
1041                 }
1042
1043                 if (pr->power.states[i].promotion.state)
1044                         seq_printf(seq, "promotion[C%zd] ",
1045                                    (pr->power.states[i].promotion.state -
1046                                     pr->power.states));
1047                 else
1048                         seq_puts(seq, "promotion[--] ");
1049
1050                 if (pr->power.states[i].demotion.state)
1051                         seq_printf(seq, "demotion[C%zd] ",
1052                                    (pr->power.states[i].demotion.state -
1053                                     pr->power.states));
1054                 else
1055                         seq_puts(seq, "demotion[--] ");
1056
1057                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1058                            pr->power.states[i].latency,
1059                            pr->power.states[i].usage,
1060                            pr->power.states[i].time);
1061         }
1062
1063       end:
1064         return 0;
1065 }
1066
1067 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1068 {
1069         return single_open(file, acpi_processor_power_seq_show,
1070                            PDE(inode)->data);
1071 }
1072
1073 static struct file_operations acpi_processor_power_fops = {
1074         .open = acpi_processor_power_open_fs,
1075         .read = seq_read,
1076         .llseek = seq_lseek,
1077         .release = single_release,
1078 };
1079
1080 int acpi_processor_power_init(struct acpi_processor *pr,
1081                               struct acpi_device *device)
1082 {
1083         acpi_status status = 0;
1084         static int first_run;
1085         struct proc_dir_entry *entry = NULL;
1086         unsigned int i;
1087
1088
1089         if (!first_run) {
1090                 dmi_check_system(processor_power_dmi_table);
1091                 if (max_cstate < ACPI_C_STATES_MAX)
1092                         printk(KERN_NOTICE
1093                                "ACPI: processor limited to max C-state %d\n",
1094                                max_cstate);
1095                 first_run++;
1096         }
1097
1098         if (!pr)
1099                 return -EINVAL;
1100
1101         if (acpi_fadt.cst_cnt && !nocst) {
1102                 status =
1103                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1104                 if (ACPI_FAILURE(status)) {
1105                         ACPI_EXCEPTION((AE_INFO, status,
1106                                         "Notifying BIOS of _CST ability failed"));
1107                 }
1108         }
1109
1110         acpi_processor_get_power_info(pr);
1111
1112         /*
1113          * Install the idle handler if processor power management is supported.
1114          * Note that we use previously set idle handler will be used on
1115          * platforms that only support C1.
1116          */
1117         if ((pr->flags.power) && (!boot_option_idle_override)) {
1118                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1119                 for (i = 1; i <= pr->power.count; i++)
1120                         if (pr->power.states[i].valid)
1121                                 printk(" C%d[C%d]", i,
1122                                        pr->power.states[i].type);
1123                 printk(")\n");
1124
1125                 if (pr->id == 0) {
1126                         pm_idle_save = pm_idle;
1127                         pm_idle = acpi_processor_idle;
1128                 }
1129         }
1130
1131         /* 'power' [R] */
1132         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1133                                   S_IRUGO, acpi_device_dir(device));
1134         if (!entry)
1135                 return -EIO;
1136         else {
1137                 entry->proc_fops = &acpi_processor_power_fops;
1138                 entry->data = acpi_driver_data(device);
1139                 entry->owner = THIS_MODULE;
1140         }
1141
1142         pr->flags.power_setup_done = 1;
1143
1144         return 0;
1145 }
1146
1147 int acpi_processor_power_exit(struct acpi_processor *pr,
1148                               struct acpi_device *device)
1149 {
1150
1151         pr->flags.power_setup_done = 0;
1152
1153         if (acpi_device_dir(device))
1154                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1155                                   acpi_device_dir(device));
1156
1157         /* Unregister the idle handler when processor #0 is removed. */
1158         if (pr->id == 0) {
1159                 pm_idle = pm_idle_save;
1160
1161                 /*
1162                  * We are about to unload the current idle thread pm callback
1163                  * (pm_idle), Wait for all processors to update cached/local
1164                  * copies of pm_idle before proceeding.
1165                  */
1166                 cpu_idle_wait();
1167         }
1168
1169         return 0;
1170 }