err.no Git - linux-2.6/blob - drivers/acpi/processor_idle.c

   1 /*
   2  * processor_idle - idle state submodule to the ACPI processor driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *                      - Added support for C3 on SMP
  11  *
  12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or (at
  17  *  your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful, but
  20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  *  General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License along
  25  *  with this program; if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  27  *
  28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/cpufreq.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/moduleparam.h>
  40 #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);
  58 module_param(max_cstate, uint, 0644);
  59
  60 static unsigned int nocst = 0;
  61 module_param(nocst, uint, 0000);
  62
  63 /*
  64  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  65  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  66  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  67  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  68  * reduce history for more aggressive entry into C3
  69  */
  70 static unsigned int bm_history =
  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 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
  98         { set_max_cstate, "IBM ThinkPad R40e", {
  99           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 100           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 101         { set_max_cstate, "IBM ThinkPad R40e", {
 102           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 103           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 104         { set_max_cstate, "IBM ThinkPad R40e", {
 105           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 106           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 107         { set_max_cstate, "IBM ThinkPad R40e", {
 108           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 109           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 110         { set_max_cstate, "IBM ThinkPad R40e", {
 111           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 112           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 113         { set_max_cstate, "IBM ThinkPad R40e", {
 114           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 115           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 116         { set_max_cstate, "IBM ThinkPad R40e", {
 117           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 118           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 119         { set_max_cstate, "IBM ThinkPad R40e", {
 120           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 121           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 122         { set_max_cstate, "IBM ThinkPad R40e", {
 123           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 124           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 125         { set_max_cstate, "IBM ThinkPad R40e", {
 126           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 127           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 128         { set_max_cstate, "IBM ThinkPad R40e", {
 129           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 130           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 131         { set_max_cstate, "IBM ThinkPad R40e", {
 132           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 133           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 134         { set_max_cstate, "IBM ThinkPad R40e", {
 135           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 136           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 137         { set_max_cstate, "IBM ThinkPad R40e", {
 138           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 139           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 140         { set_max_cstate, "IBM ThinkPad R40e", {
 141           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 142           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 143         { set_max_cstate, "Medion 41700", {
 144           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 145           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 146         { set_max_cstate, "Clevo 5600D", {
 147           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 148           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 149          (void *)2},
 150         {},
 151 };
 152
 153 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 154 {
 155         if (t2 >= t1)
 156                 return (t2 - t1);
 157         else if (!acpi_fadt.tmr_val_ext)
 158                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 159         else
 160                 return ((0xFFFFFFFF - t1) + t2);
 161 }
 162
 163 static void
 164 acpi_processor_power_activate(struct acpi_processor *pr,
 165                               struct acpi_processor_cx *new)
 166 {
 167         struct acpi_processor_cx *old;
 168
 169         if (!pr || !new)
 170                 return;
 171
 172         old = pr->power.state;
 173
 174         if (old)
 175                 old->promotion.count = 0;
 176         new->demotion.count = 0;
 177
 178         /* Cleanup from old state. */
 179         if (old) {
 180                 switch (old->type) {
 181                 case ACPI_STATE_C3:
 182                         /* Disable bus master reload */
 183                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 184                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
 185                                                   ACPI_MTX_DO_NOT_LOCK);
 186                         break;
 187                 }
 188         }
 189
 190         /* Prepare to use new state. */
 191         switch (new->type) {
 192         case ACPI_STATE_C3:
 193                 /* Enable bus master reload */
 194                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 195                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
 196                                           ACPI_MTX_DO_NOT_LOCK);
 197                 break;
 198         }
 199
 200         pr->power.state = new;
 201
 202         return;
 203 }
 204
 205 static void acpi_safe_halt(void)
 206 {
 207         clear_thread_flag(TIF_POLLING_NRFLAG);
 208         smp_mb__after_clear_bit();
 209         if (!need_resched())
 210                 safe_halt();
 211         set_thread_flag(TIF_POLLING_NRFLAG);
 212 }
 213
 214 static atomic_t c3_cpu_count;
 215
 216 static void acpi_processor_idle(void)
 217 {
 218         struct acpi_processor *pr = NULL;
 219         struct acpi_processor_cx *cx = NULL;
 220         struct acpi_processor_cx *next_state = NULL;
 221         int sleep_ticks = 0;
 222         u32 t1, t2 = 0;
 223
 224         pr = processors[smp_processor_id()];
 225         if (!pr)
 226                 return;
 227
 228         /*
 229          * Interrupts must be disabled during bus mastering calculations and
 230          * for C2/C3 transitions.
 231          */
 232         local_irq_disable();
 233
 234         /*
 235          * Check whether we truly need to go idle, or should
 236          * reschedule:
 237          */
 238         if (unlikely(need_resched())) {
 239                 local_irq_enable();
 240                 return;
 241         }
 242
 243         cx = pr->power.state;
 244         if (!cx) {
 245                 if (pm_idle_save)
 246                         pm_idle_save();
 247                 else
 248                         acpi_safe_halt();
 249                 return;
 250         }
 251
 252         /*
 253          * Check BM Activity
 254          * -----------------
 255          * Check for bus mastering activity (if required), record, and check
 256          * for demotion.
 257          */
 258         if (pr->flags.bm_check) {
 259                 u32 bm_status = 0;
 260                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 261
 262                 if (diff > 32)
 263                         diff = 32;
 264
 265                 while (diff) {
 266                         /* if we didn't get called, assume there was busmaster activity */
 267                         diff--;
 268                         if (diff)
 269                                 pr->power.bm_activity |= 0x1;
 270                         pr->power.bm_activity <<= 1;
 271                 }
 272
 273                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 274                                   &bm_status, ACPI_MTX_DO_NOT_LOCK);
 275                 if (bm_status) {
 276                         pr->power.bm_activity++;
 277                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 278                                           1, ACPI_MTX_DO_NOT_LOCK);
 279                 }
 280                 /*
 281                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 282                  * the true state of bus mastering activity; forcing us to
 283                  * manually check the BMIDEA bit of each IDE channel.
 284                  */
 285                 else if (errata.piix4.bmisx) {
 286                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 287                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 288                                 pr->power.bm_activity++;
 289                 }
 290
 291                 pr->power.bm_check_timestamp = jiffies;
 292
 293                 /*
 294                  * Apply bus mastering demotion policy.  Automatically demote
 295                  * to avoid a faulty transition.  Note that the processor
 296                  * won't enter a low-power state during this call (to this
 297                  * funciton) but should upon the next.
 298                  *
 299                  * TBD: A better policy might be to fallback to the demotion
 300                  *      state (use it for this quantum only) istead of
 301                  *      demoting -- and rely on duration as our sole demotion
 302                  *      qualification.  This may, however, introduce DMA
 303                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 304                  */
 305                 if (pr->power.bm_activity & 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         cx->usage++;
 324
 325         /*
 326          * Sleep:
 327          * ------
 328          * Invoke the current Cx state to put the processor to sleep.
 329          */
 330         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 331                 clear_thread_flag(TIF_POLLING_NRFLAG);
 332                 smp_mb__after_clear_bit();
 333                 if (need_resched()) {
 334                         set_thread_flag(TIF_POLLING_NRFLAG);
 335                         local_irq_enable();
 336                         return;
 337                 }
 338         }
 339
 340         switch (cx->type) {
 341
 342         case ACPI_STATE_C1:
 343                 /*
 344                  * Invoke C1.
 345                  * Use the appropriate idle routine, the one that would
 346                  * be used without acpi C-states.
 347                  */
 348                 if (pm_idle_save)
 349                         pm_idle_save();
 350                 else
 351                         acpi_safe_halt();
 352
 353                 /*
 354                  * TBD: Can't get time duration while in C1, as resumes
 355                  *      go to an ISR rather than here.  Need to instrument
 356                  *      base interrupt handler.
 357                  */
 358                 sleep_ticks = 0xFFFFFFFF;
 359                 break;
 360
 361         case ACPI_STATE_C2:
 362                 /* Get start time (ticks) */
 363                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 364                 /* Invoke C2 */
 365                 inb(cx->address);
 366                 /* Dummy op - must do something useless after P_LVL2 read */
 367                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 368                 /* Get end time (ticks) */
 369                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 370                 /* Re-enable interrupts */
 371                 local_irq_enable();
 372                 set_thread_flag(TIF_POLLING_NRFLAG);
 373                 /* Compute time (ticks) that we were actually asleep */
 374                 sleep_ticks =
 375                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 376                 break;
 377
 378         case ACPI_STATE_C3:
 379
 380                 if (pr->flags.bm_check) {
 381                         if (atomic_inc_return(&c3_cpu_count) ==
 382                             num_online_cpus()) {
 383                                 /*
 384                                  * All CPUs are trying to go to C3
 385                                  * Disable bus master arbitration
 386                                  */
 387                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
 388                                                   ACPI_MTX_DO_NOT_LOCK);
 389                         }
 390                 } else {
 391                         /* SMP with no shared cache... Invalidate cache  */
 392                         ACPI_FLUSH_CPU_CACHE();
 393                 }
 394
 395                 /* Get start time (ticks) */
 396                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 397                 /* Invoke C3 */
 398                 inb(cx->address);
 399                 /* Dummy op - must do something useless after P_LVL3 read */
 400                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 401                 /* Get end time (ticks) */
 402                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 403                 if (pr->flags.bm_check) {
 404                         /* Enable bus master arbitration */
 405                         atomic_dec(&c3_cpu_count);
 406                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
 407                                           ACPI_MTX_DO_NOT_LOCK);
 408                 }
 409
 410                 /* Re-enable interrupts */
 411                 local_irq_enable();
 412                 set_thread_flag(TIF_POLLING_NRFLAG);
 413                 /* Compute time (ticks) that we were actually asleep */
 414                 sleep_ticks =
 415                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 416                 break;
 417
 418         default:
 419                 local_irq_enable();
 420                 return;
 421         }
 422
 423         next_state = pr->power.state;
 424
 425 #ifdef CONFIG_HOTPLUG_CPU
 426         /* Don't do promotion/demotion */
 427         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 428             !pr->flags.has_cst && !acpi_fadt.plvl2_up) {
 429                 next_state = cx;
 430                 goto end;
 431         }
 432 #endif
 433
 434         /*
 435          * Promotion?
 436          * ----------
 437          * Track the number of longs (time asleep is greater than threshold)
 438          * and promote when the count threshold is reached.  Note that bus
 439          * mastering activity may prevent promotions.
 440          * Do not promote above max_cstate.
 441          */
 442         if (cx->promotion.state &&
 443             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 444                 if (sleep_ticks > cx->promotion.threshold.ticks) {
 445                         cx->promotion.count++;
 446                         cx->demotion.count = 0;
 447                         if (cx->promotion.count >=
 448                             cx->promotion.threshold.count) {
 449                                 if (pr->flags.bm_check) {
 450                                         if (!
 451                                             (pr->power.bm_activity & cx->
 452                                              promotion.threshold.bm)) {
 453                                                 next_state =
 454                                                     cx->promotion.state;
 455                                                 goto end;
 456                                         }
 457                                 } else {
 458                                         next_state = cx->promotion.state;
 459                                         goto end;
 460                                 }
 461                         }
 462                 }
 463         }
 464
 465         /*
 466          * Demotion?
 467          * ---------
 468          * Track the number of shorts (time asleep is less than time threshold)
 469          * and demote when the usage threshold is reached.
 470          */
 471         if (cx->demotion.state) {
 472                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 473                         cx->demotion.count++;
 474                         cx->promotion.count = 0;
 475                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 476                                 next_state = cx->demotion.state;
 477                                 goto end;
 478                         }
 479                 }
 480         }
 481
 482       end:
 483         /*
 484          * Demote if current state exceeds max_cstate
 485          */
 486         if ((pr->power.state - pr->power.states) > max_cstate) {
 487                 if (cx->demotion.state)
 488                         next_state = cx->demotion.state;
 489         }
 490
 491         /*
 492          * New Cx State?
 493          * -------------
 494          * If we're going to start using a new Cx state we must clean up
 495          * from the previous and prepare to use the new.
 496          */
 497         if (next_state != pr->power.state)
 498                 acpi_processor_power_activate(pr, next_state);
 499 }
 500
 501 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 502 {
 503         unsigned int i;
 504         unsigned int state_is_set = 0;
 505         struct acpi_processor_cx *lower = NULL;
 506         struct acpi_processor_cx *higher = NULL;
 507         struct acpi_processor_cx *cx;
 508
 509         ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
 510
 511         if (!pr)
 512                 return_VALUE(-EINVAL);
 513
 514         /*
 515          * This function sets the default Cx state policy (OS idle handler).
 516          * Our scheme is to promote quickly to C2 but more conservatively
 517          * to C3.  We're favoring C2  for its characteristics of low latency
 518          * (quick response), good power savings, and ability to allow bus
 519          * mastering activity.  Note that the Cx state policy is completely
 520          * customizable and can be altered dynamically.
 521          */
 522
 523         /* startup state */
 524         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 525                 cx = &pr->power.states[i];
 526                 if (!cx->valid)
 527                         continue;
 528
 529                 if (!state_is_set)
 530                         pr->power.state = cx;
 531                 state_is_set++;
 532                 break;
 533         }
 534
 535         if (!state_is_set)
 536                 return_VALUE(-ENODEV);
 537
 538         /* demotion */
 539         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 540                 cx = &pr->power.states[i];
 541                 if (!cx->valid)
 542                         continue;
 543
 544                 if (lower) {
 545                         cx->demotion.state = lower;
 546                         cx->demotion.threshold.ticks = cx->latency_ticks;
 547                         cx->demotion.threshold.count = 1;
 548                         if (cx->type == ACPI_STATE_C3)
 549                                 cx->demotion.threshold.bm = bm_history;
 550                 }
 551
 552                 lower = cx;
 553         }
 554
 555         /* promotion */
 556         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 557                 cx = &pr->power.states[i];
 558                 if (!cx->valid)
 559                         continue;
 560
 561                 if (higher) {
 562                         cx->promotion.state = higher;
 563                         cx->promotion.threshold.ticks = cx->latency_ticks;
 564                         if (cx->type >= ACPI_STATE_C2)
 565                                 cx->promotion.threshold.count = 4;
 566                         else
 567                                 cx->promotion.threshold.count = 10;
 568                         if (higher->type == ACPI_STATE_C3)
 569                                 cx->promotion.threshold.bm = bm_history;
 570                 }
 571
 572                 higher = cx;
 573         }
 574
 575         return_VALUE(0);
 576 }
 577
 578 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 579 {
 580         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
 581
 582         if (!pr)
 583                 return_VALUE(-EINVAL);
 584
 585         if (!pr->pblk)
 586                 return_VALUE(-ENODEV);
 587
 588         memset(pr->power.states, 0, sizeof(pr->power.states));
 589
 590         /* if info is obtained from pblk/fadt, type equals state */
 591         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 592         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 593         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 594
 595         /* the C0 state only exists as a filler in our array,
 596          * and all processors need to support C1 */
 597         pr->power.states[ACPI_STATE_C0].valid = 1;
 598         pr->power.states[ACPI_STATE_C1].valid = 1;
 599
 600 #ifndef CONFIG_HOTPLUG_CPU
 601         /*
 602          * Check for P_LVL2_UP flag before entering C2 and above on
 603          * an SMP system.
 604          */
 605         if ((num_online_cpus() > 1) && !acpi_fadt.plvl2_up)
 606                 return_VALUE(-ENODEV);
 607 #endif
 608
 609         /* determine C2 and C3 address from pblk */
 610         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 611         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 612
 613         /* determine latencies from FADT */
 614         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 615         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 616
 617         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 618                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 619                           pr->power.states[ACPI_STATE_C2].address,
 620                           pr->power.states[ACPI_STATE_C3].address));
 621
 622         return_VALUE(0);
 623 }
 624
 625 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
 626 {
 627         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
 628
 629         memset(pr->power.states, 0, sizeof(pr->power.states));
 630
 631         /* if info is obtained from pblk/fadt, type equals state */
 632         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 633         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 634         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 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_VALUE(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 i;
 649         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 650         union acpi_object *cst;
 651
 652         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
 653
 654         if (nocst)
 655                 return_VALUE(-ENODEV);
 656
 657         pr->power.count = 0;
 658         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
 659                 memset(&(pr->power.states[i]), 0,
 660                        sizeof(struct acpi_processor_cx));
 661
 662         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 663         if (ACPI_FAILURE(status)) {
 664                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 665                 return_VALUE(-ENODEV);
 666         }
 667
 668         cst = (union acpi_object *)buffer.pointer;
 669
 670         /* There must be at least 2 elements */
 671         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 672                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 673                                   "not enough elements in _CST\n"));
 674                 status = -EFAULT;
 675                 goto end;
 676         }
 677
 678         count = cst->package.elements[0].integer.value;
 679
 680         /* Validate number of power states. */
 681         if (count < 1 || count != cst->package.count - 1) {
 682                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 683                                   "count given by _CST is not valid\n"));
 684                 status = -EFAULT;
 685                 goto end;
 686         }
 687
 688         /* We support up to ACPI_PROCESSOR_MAX_POWER. */
 689         if (count > ACPI_PROCESSOR_MAX_POWER) {
 690                 printk(KERN_WARNING
 691                        "Limiting number of power states to max (%d)\n",
 692                        ACPI_PROCESSOR_MAX_POWER);
 693                 printk(KERN_WARNING
 694                        "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 695                 count = ACPI_PROCESSOR_MAX_POWER;
 696         }
 697
 698         /* Tell driver that at least _CST is supported. */
 699         pr->flags.has_cst = 1;
 700
 701         for (i = 1; i <= count; i++) {
 702                 union acpi_object *element;
 703                 union acpi_object *obj;
 704                 struct acpi_power_register *reg;
 705                 struct acpi_processor_cx cx;
 706
 707                 memset(&cx, 0, sizeof(cx));
 708
 709                 element = (union acpi_object *)&(cst->package.elements[i]);
 710                 if (element->type != ACPI_TYPE_PACKAGE)
 711                         continue;
 712
 713                 if (element->package.count != 4)
 714                         continue;
 715
 716                 obj = (union acpi_object *)&(element->package.elements[0]);
 717
 718                 if (obj->type != ACPI_TYPE_BUFFER)
 719                         continue;
 720
 721                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 722
 723                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 724                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 725                         continue;
 726
 727                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
 728                     0 : reg->address;
 729
 730                 /* There should be an easy way to extract an integer... */
 731                 obj = (union acpi_object *)&(element->package.elements[1]);
 732                 if (obj->type != ACPI_TYPE_INTEGER)
 733                         continue;
 734
 735                 cx.type = obj->integer.value;
 736
 737                 if ((cx.type != ACPI_STATE_C1) &&
 738                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
 739                         continue;
 740
 741                 if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3))
 742                         continue;
 743
 744                 obj = (union acpi_object *)&(element->package.elements[2]);
 745                 if (obj->type != ACPI_TYPE_INTEGER)
 746                         continue;
 747
 748                 cx.latency = obj->integer.value;
 749
 750                 obj = (union acpi_object *)&(element->package.elements[3]);
 751                 if (obj->type != ACPI_TYPE_INTEGER)
 752                         continue;
 753
 754                 cx.power = obj->integer.value;
 755
 756                 (pr->power.count)++;
 757                 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
 758         }
 759
 760         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 761                           pr->power.count));
 762
 763         /* Validate number of power states discovered */
 764         if (pr->power.count < 2)
 765                 status = -EFAULT;
 766
 767       end:
 768         acpi_os_free(buffer.pointer);
 769
 770         return_VALUE(status);
 771 }
 772
 773 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 774 {
 775         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
 776
 777         if (!cx->address)
 778                 return_VOID;
 779
 780         /*
 781          * C2 latency must be less than or equal to 100
 782          * microseconds.
 783          */
 784         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 785                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 786                                   "latency too large [%d]\n", cx->latency));
 787                 return_VOID;
 788         }
 789
 790         /*
 791          * Otherwise we've met all of our C2 requirements.
 792          * Normalize the C2 latency to expidite policy
 793          */
 794         cx->valid = 1;
 795         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 796
 797         return_VOID;
 798 }
 799
 800 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 801                                            struct acpi_processor_cx *cx)
 802 {
 803         static int bm_check_flag;
 804
 805         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
 806
 807         if (!cx->address)
 808                 return_VOID;
 809
 810         /*
 811          * C3 latency must be less than or equal to 1000
 812          * microseconds.
 813          */
 814         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 815                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 816                                   "latency too large [%d]\n", cx->latency));
 817                 return_VOID;
 818         }
 819
 820         /*
 821          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 822          * DMA transfers are used by any ISA device to avoid livelock.
 823          * Note that we could disable Type-F DMA (as recommended by
 824          * the erratum), but this is known to disrupt certain ISA
 825          * devices thus we take the conservative approach.
 826          */
 827         else if (errata.piix4.fdma) {
 828                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 829                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 830                 return_VOID;
 831         }
 832
 833         /* All the logic here assumes flags.bm_check is same across all CPUs */
 834         if (!bm_check_flag) {
 835                 /* Determine whether bm_check is needed based on CPU  */
 836                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 837                 bm_check_flag = pr->flags.bm_check;
 838         } else {
 839                 pr->flags.bm_check = bm_check_flag;
 840         }
 841
 842         if (pr->flags.bm_check) {
 843                 /* bus mastering control is necessary */
 844                 if (!pr->flags.bm_control) {
 845                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 846                                           "C3 support requires bus mastering control\n"));
 847                         return_VOID;
 848                 }
 849         } else {
 850                 /*
 851                  * WBINVD should be set in fadt, for C3 state to be
 852                  * supported on when bm_check is not required.
 853                  */
 854                 if (acpi_fadt.wb_invd != 1) {
 855                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 856                                           "Cache invalidation should work properly"
 857                                           " for C3 to be enabled on SMP systems\n"));
 858                         return_VOID;
 859                 }
 860                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
 861                                   0, ACPI_MTX_DO_NOT_LOCK);
 862         }
 863
 864         /*
 865          * Otherwise we've met all of our C3 requirements.
 866          * Normalize the C3 latency to expidite policy.  Enable
 867          * checking of bus mastering status (bm_check) so we can
 868          * use this in our C3 policy
 869          */
 870         cx->valid = 1;
 871         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 872
 873         return_VOID;
 874 }
 875
 876 static int acpi_processor_power_verify(struct acpi_processor *pr)
 877 {
 878         unsigned int i;
 879         unsigned int working = 0;
 880
 881         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 882                 struct acpi_processor_cx *cx = &pr->power.states[i];
 883
 884                 switch (cx->type) {
 885                 case ACPI_STATE_C1:
 886                         cx->valid = 1;
 887                         break;
 888
 889                 case ACPI_STATE_C2:
 890                         acpi_processor_power_verify_c2(cx);
 891                         break;
 892
 893                 case ACPI_STATE_C3:
 894                         acpi_processor_power_verify_c3(pr, cx);
 895                         break;
 896                 }
 897
 898                 if (cx->valid)
 899                         working++;
 900         }
 901
 902         return (working);
 903 }
 904
 905 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 906 {
 907         unsigned int i;
 908         int result;
 909
 910         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
 911
 912         /* NOTE: the idle thread may not be running while calling
 913          * this function */
 914
 915         result = acpi_processor_get_power_info_cst(pr);
 916         if (result == -ENODEV)
 917                 result = acpi_processor_get_power_info_fadt(pr);
 918
 919         if ((result) || (acpi_processor_power_verify(pr) < 2))
 920                 result = acpi_processor_get_power_info_default_c1(pr);
 921
 922         /*
 923          * Set Default Policy
 924          * ------------------
 925          * Now that we know which states are supported, set the default
 926          * policy.  Note that this policy can be changed dynamically
 927          * (e.g. encourage deeper sleeps to conserve battery life when
 928          * not on AC).
 929          */
 930         result = acpi_processor_set_power_policy(pr);
 931         if (result)
 932                 return_VALUE(result);
 933
 934         /*
 935          * if one state of type C2 or C3 is available, mark this
 936          * CPU as being "idle manageable"
 937          */
 938         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 939                 if (pr->power.states[i].valid) {
 940                         pr->power.count = i;
 941                         if (pr->power.states[i].type >= ACPI_STATE_C2)
 942                                 pr->flags.power = 1;
 943                 }
 944         }
 945
 946         return_VALUE(0);
 947 }
 948
 949 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 950 {
 951         int result = 0;
 952
 953         ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
 954
 955         if (!pr)
 956                 return_VALUE(-EINVAL);
 957
 958         if (nocst) {
 959                 return_VALUE(-ENODEV);
 960         }
 961
 962         if (!pr->flags.power_setup_done)
 963                 return_VALUE(-ENODEV);
 964
 965         /* Fall back to the default idle loop */
 966         pm_idle = pm_idle_save;
 967         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
 968
 969         pr->flags.power = 0;
 970         result = acpi_processor_get_power_info(pr);
 971         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
 972                 pm_idle = acpi_processor_idle;
 973
 974         return_VALUE(result);
 975 }
 976
 977 /* proc interface */
 978
 979 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
 980 {
 981         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 982         unsigned int i;
 983
 984         ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
 985
 986         if (!pr)
 987                 goto end;
 988
 989         seq_printf(seq, "active state:            C%zd\n"
 990                    "max_cstate:              C%d\n"
 991                    "bus master activity:     %08x\n",
 992                    pr->power.state ? pr->power.state - pr->power.states : 0,
 993                    max_cstate, (unsigned)pr->power.bm_activity);
 994
 995         seq_puts(seq, "states:\n");
 996
 997         for (i = 1; i <= pr->power.count; i++) {
 998                 seq_printf(seq, "   %cC%d:                  ",
 999                            (&pr->power.states[i] ==
1000                             pr->power.state ? '*' : ' '), i);
1001
1002                 if (!pr->power.states[i].valid) {
1003                         seq_puts(seq, "<not supported>\n");
1004                         continue;
1005                 }
1006
1007                 switch (pr->power.states[i].type) {
1008                 case ACPI_STATE_C1:
1009                         seq_printf(seq, "type[C1] ");
1010                         break;
1011                 case ACPI_STATE_C2:
1012                         seq_printf(seq, "type[C2] ");
1013                         break;
1014                 case ACPI_STATE_C3:
1015                         seq_printf(seq, "type[C3] ");
1016                         break;
1017                 default:
1018                         seq_printf(seq, "type[--] ");
1019                         break;
1020                 }
1021
1022                 if (pr->power.states[i].promotion.state)
1023                         seq_printf(seq, "promotion[C%zd] ",
1024                                    (pr->power.states[i].promotion.state -
1025                                     pr->power.states));
1026                 else
1027                         seq_puts(seq, "promotion[--] ");
1028
1029                 if (pr->power.states[i].demotion.state)
1030                         seq_printf(seq, "demotion[C%zd] ",
1031                                    (pr->power.states[i].demotion.state -
1032                                     pr->power.states));
1033                 else
1034                         seq_puts(seq, "demotion[--] ");
1035
1036                 seq_printf(seq, "latency[%03d] usage[%08d]\n",
1037                            pr->power.states[i].latency,
1038                            pr->power.states[i].usage);
1039         }
1040
1041       end:
1042         return_VALUE(0);
1043 }
1044
1045 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1046 {
1047         return single_open(file, acpi_processor_power_seq_show,
1048                            PDE(inode)->data);
1049 }
1050
1051 static struct file_operations acpi_processor_power_fops = {
1052         .open = acpi_processor_power_open_fs,
1053         .read = seq_read,
1054         .llseek = seq_lseek,
1055         .release = single_release,
1056 };
1057
1058 int acpi_processor_power_init(struct acpi_processor *pr,
1059                               struct acpi_device *device)
1060 {
1061         acpi_status status = 0;
1062         static int first_run = 0;
1063         struct proc_dir_entry *entry = NULL;
1064         unsigned int i;
1065
1066         ACPI_FUNCTION_TRACE("acpi_processor_power_init");
1067
1068         if (!first_run) {
1069                 dmi_check_system(processor_power_dmi_table);
1070                 if (max_cstate < ACPI_C_STATES_MAX)
1071                         printk(KERN_NOTICE
1072                                "ACPI: processor limited to max C-state %d\n",
1073                                max_cstate);
1074                 first_run++;
1075         }
1076
1077         if (!pr)
1078                 return_VALUE(-EINVAL);
1079
1080         if (acpi_fadt.cst_cnt && !nocst) {
1081                 status =
1082                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1083                 if (ACPI_FAILURE(status)) {
1084                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1085                                           "Notifying BIOS of _CST ability failed\n"));
1086                 }
1087         }
1088
1089         acpi_processor_power_init_pdc(&(pr->power), pr->id);
1090         acpi_processor_set_pdc(pr, pr->power.pdc);
1091         acpi_processor_get_power_info(pr);
1092
1093         /*
1094          * Install the idle handler if processor power management is supported.
1095          * Note that we use previously set idle handler will be used on
1096          * platforms that only support C1.
1097          */
1098         if ((pr->flags.power) && (!boot_option_idle_override)) {
1099                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1100                 for (i = 1; i <= pr->power.count; i++)
1101                         if (pr->power.states[i].valid)
1102                                 printk(" C%d[C%d]", i,
1103                                        pr->power.states[i].type);
1104                 printk(")\n");
1105
1106                 if (pr->id == 0) {
1107                         pm_idle_save = pm_idle;
1108                         pm_idle = acpi_processor_idle;
1109                 }
1110         }
1111
1112         /* 'power' [R] */
1113         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1114                                   S_IRUGO, acpi_device_dir(device));
1115         if (!entry)
1116                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1117                                   "Unable to create '%s' fs entry\n",
1118                                   ACPI_PROCESSOR_FILE_POWER));
1119         else {
1120                 entry->proc_fops = &acpi_processor_power_fops;
1121                 entry->data = acpi_driver_data(device);
1122                 entry->owner = THIS_MODULE;
1123         }
1124
1125         pr->flags.power_setup_done = 1;
1126
1127         return_VALUE(0);
1128 }
1129
1130 int acpi_processor_power_exit(struct acpi_processor *pr,
1131                               struct acpi_device *device)
1132 {
1133         ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
1134
1135         pr->flags.power_setup_done = 0;
1136
1137         if (acpi_device_dir(device))
1138                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1139                                   acpi_device_dir(device));
1140
1141         /* Unregister the idle handler when processor #0 is removed. */
1142         if (pr->id == 0) {
1143                 pm_idle = pm_idle_save;
1144
1145                 /*
1146                  * We are about to unload the current idle thread pm callback
1147                  * (pm_idle), Wait for all processors to update cached/local
1148                  * copies of pm_idle before proceeding.
1149                  */
1150                 cpu_idle_wait();
1151         }
1152
1153         return_VALUE(0);
1154 }