git.oblomov.eu 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, 2005 Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *                      - Added support for C3 on SMP
  11  *
  12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or (at
  17  *  your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful, but
  20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  *  General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License along
  25  *  with this program; if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  27  *
  28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/cpufreq.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/sched.h>        /* need_resched() */
  41 #include <linux/latency.h>
  42
  43 #include <asm/io.h>
  44 #include <asm/uaccess.h>
  45
  46 #include <acpi/acpi_bus.h>
  47 #include <acpi/processor.h>
  48
  49 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  50 #define ACPI_PROCESSOR_CLASS            "processor"
  51 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
  52 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  53 ACPI_MODULE_NAME("acpi_processor")
  54 #define ACPI_PROCESSOR_FILE_POWER       "power"
  55 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  56 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  57 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  58 static void (*pm_idle_save) (void) __read_mostly;
  59 module_param(max_cstate, uint, 0644);
  60
  61 static unsigned int nocst __read_mostly;
  62 module_param(nocst, uint, 0000);
  63
  64 /*
  65  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  66  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  67  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  68  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  69  * reduce history for more aggressive entry into C3
  70  */
  71 static unsigned int bm_history __read_mostly =
  72     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  73 module_param(bm_history, uint, 0644);
  74 /* --------------------------------------------------------------------------
  75                                 Power Management
  76    -------------------------------------------------------------------------- */
  77
  78 /*
  79  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  80  * For now disable this. Probably a bug somewhere else.
  81  *
  82  * To skip this limit, boot/load with a large max_cstate limit.
  83  */
  84 static int set_max_cstate(struct dmi_system_id *id)
  85 {
  86         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  87                 return 0;
  88
  89         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
  90                " Override with \"processor.max_cstate=%d\"\n", id->ident,
  91                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  92
  93         max_cstate = (long)id->driver_data;
  94
  95         return 0;
  96 }
  97
  98 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
  99    callers to only run once -AK */
 100 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 101         { set_max_cstate, "IBM ThinkPad R40e", {
 102           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 103           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 104         { set_max_cstate, "IBM ThinkPad R40e", {
 105           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 106           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 107         { set_max_cstate, "IBM ThinkPad R40e", {
 108           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 109           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 110         { set_max_cstate, "IBM ThinkPad R40e", {
 111           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 112           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 113         { set_max_cstate, "IBM ThinkPad R40e", {
 114           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 115           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 116         { set_max_cstate, "IBM ThinkPad R40e", {
 117           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 118           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 119         { set_max_cstate, "IBM ThinkPad R40e", {
 120           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 121           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 122         { set_max_cstate, "IBM ThinkPad R40e", {
 123           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 124           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 125         { set_max_cstate, "IBM ThinkPad R40e", {
 126           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 127           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 128         { set_max_cstate, "IBM ThinkPad R40e", {
 129           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 130           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 131         { set_max_cstate, "IBM ThinkPad R40e", {
 132           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 133           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 134         { set_max_cstate, "IBM ThinkPad R40e", {
 135           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 136           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 137         { set_max_cstate, "IBM ThinkPad R40e", {
 138           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 139           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 140         { set_max_cstate, "IBM ThinkPad R40e", {
 141           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 142           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 143         { set_max_cstate, "IBM ThinkPad R40e", {
 144           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 145           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 146         { set_max_cstate, "IBM ThinkPad R40e", {
 147           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 148           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 149         { set_max_cstate, "Medion 41700", {
 150           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 151           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 152         { set_max_cstate, "Clevo 5600D", {
 153           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 154           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 155          (void *)2},
 156         {},
 157 };
 158
 159 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 160 {
 161         if (t2 >= t1)
 162                 return (t2 - t1);
 163         else if (!acpi_fadt.tmr_val_ext)
 164                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 165         else
 166                 return ((0xFFFFFFFF - t1) + t2);
 167 }
 168
 169 static void
 170 acpi_processor_power_activate(struct acpi_processor *pr,
 171                               struct acpi_processor_cx *new)
 172 {
 173         struct acpi_processor_cx *old;
 174
 175         if (!pr || !new)
 176                 return;
 177
 178         old = pr->power.state;
 179
 180         if (old)
 181                 old->promotion.count = 0;
 182         new->demotion.count = 0;
 183
 184         /* Cleanup from old state. */
 185         if (old) {
 186                 switch (old->type) {
 187                 case ACPI_STATE_C3:
 188                         /* Disable bus master reload */
 189                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 190                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
 191                                                   ACPI_MTX_DO_NOT_LOCK);
 192                         break;
 193                 }
 194         }
 195
 196         /* Prepare to use new state. */
 197         switch (new->type) {
 198         case ACPI_STATE_C3:
 199                 /* Enable bus master reload */
 200                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 201                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
 202                                           ACPI_MTX_DO_NOT_LOCK);
 203                 break;
 204         }
 205
 206         pr->power.state = new;
 207
 208         return;
 209 }
 210
 211 static void acpi_safe_halt(void)
 212 {
 213         current_thread_info()->status &= ~TS_POLLING;
 214         smp_mb__after_clear_bit();
 215         if (!need_resched())
 216                 safe_halt();
 217         current_thread_info()->status |= TS_POLLING;
 218 }
 219
 220 static atomic_t c3_cpu_count;
 221
 222 /* Common C-state entry for C2, C3, .. */
 223 static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
 224 {
 225         if (cstate->space_id == ACPI_CSTATE_FFH) {
 226                 /* Call into architectural FFH based C-state */
 227                 acpi_processor_ffh_cstate_enter(cstate);
 228         } else {
 229                 int unused;
 230                 /* IO port based C-state */
 231                 inb(cstate->address);
 232                 /* Dummy wait op - must do something useless after P_LVL2 read
 233                    because chipsets cannot guarantee that STPCLK# signal
 234                    gets asserted in time to freeze execution properly. */
 235                 unused = inl(acpi_fadt.xpm_tmr_blk.address);
 236         }
 237 }
 238
 239 static void acpi_processor_idle(void)
 240 {
 241         struct acpi_processor *pr = NULL;
 242         struct acpi_processor_cx *cx = NULL;
 243         struct acpi_processor_cx *next_state = NULL;
 244         int sleep_ticks = 0;
 245         u32 t1, t2 = 0;
 246
 247         pr = processors[smp_processor_id()];
 248         if (!pr)
 249                 return;
 250
 251         /*
 252          * Interrupts must be disabled during bus mastering calculations and
 253          * for C2/C3 transitions.
 254          */
 255         local_irq_disable();
 256
 257         /*
 258          * Check whether we truly need to go idle, or should
 259          * reschedule:
 260          */
 261         if (unlikely(need_resched())) {
 262                 local_irq_enable();
 263                 return;
 264         }
 265
 266         cx = pr->power.state;
 267         if (!cx) {
 268                 if (pm_idle_save)
 269                         pm_idle_save();
 270                 else
 271                         acpi_safe_halt();
 272                 return;
 273         }
 274
 275         /*
 276          * Check BM Activity
 277          * -----------------
 278          * Check for bus mastering activity (if required), record, and check
 279          * for demotion.
 280          */
 281         if (pr->flags.bm_check) {
 282                 u32 bm_status = 0;
 283                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 284
 285                 if (diff > 31)
 286                         diff = 31;
 287
 288                 pr->power.bm_activity <<= diff;
 289
 290                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 291                                   &bm_status, ACPI_MTX_DO_NOT_LOCK);
 292                 if (bm_status) {
 293                         pr->power.bm_activity |= 0x1;
 294                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 295                                           1, ACPI_MTX_DO_NOT_LOCK);
 296                 }
 297                 /*
 298                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 299                  * the true state of bus mastering activity; forcing us to
 300                  * manually check the BMIDEA bit of each IDE channel.
 301                  */
 302                 else if (errata.piix4.bmisx) {
 303                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 304                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 305                                 pr->power.bm_activity |= 0x1;
 306                 }
 307
 308                 pr->power.bm_check_timestamp = jiffies;
 309
 310                 /*
 311                  * If bus mastering is or was active this jiffy, demote
 312                  * to avoid a faulty transition.  Note that the processor
 313                  * won't enter a low-power state during this call (to this
 314                  * function) but should upon the next.
 315                  *
 316                  * TBD: A better policy might be to fallback to the demotion
 317                  *      state (use it for this quantum only) istead of
 318                  *      demoting -- and rely on duration as our sole demotion
 319                  *      qualification.  This may, however, introduce DMA
 320                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 321                  */
 322                 if ((pr->power.bm_activity & 0x1) &&
 323                     cx->demotion.threshold.bm) {
 324                         local_irq_enable();
 325                         next_state = cx->demotion.state;
 326                         goto end;
 327                 }
 328         }
 329
 330 #ifdef CONFIG_HOTPLUG_CPU
 331         /*
 332          * Check for P_LVL2_UP flag before entering C2 and above on
 333          * an SMP system. We do it here instead of doing it at _CST/P_LVL
 334          * detection phase, to work cleanly with logical CPU hotplug.
 335          */
 336         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 337             !pr->flags.has_cst && !acpi_fadt.plvl2_up)
 338                 cx = &pr->power.states[ACPI_STATE_C1];
 339 #endif
 340
 341         /*
 342          * Sleep:
 343          * ------
 344          * Invoke the current Cx state to put the processor to sleep.
 345          */
 346         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 347                 current_thread_info()->status &= ~TS_POLLING;
 348                 smp_mb__after_clear_bit();
 349                 if (need_resched()) {
 350                         current_thread_info()->status |= TS_POLLING;
 351                         local_irq_enable();
 352                         return;
 353                 }
 354         }
 355
 356         switch (cx->type) {
 357
 358         case ACPI_STATE_C1:
 359                 /*
 360                  * Invoke C1.
 361                  * Use the appropriate idle routine, the one that would
 362                  * be used without acpi C-states.
 363                  */
 364                 if (pm_idle_save)
 365                         pm_idle_save();
 366                 else
 367                         acpi_safe_halt();
 368
 369                 /*
 370                  * TBD: Can't get time duration while in C1, as resumes
 371                  *      go to an ISR rather than here.  Need to instrument
 372                  *      base interrupt handler.
 373                  */
 374                 sleep_ticks = 0xFFFFFFFF;
 375                 break;
 376
 377         case ACPI_STATE_C2:
 378                 /* Get start time (ticks) */
 379                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 380                 /* Invoke C2 */
 381                 acpi_cstate_enter(cx);
 382                 /* Get end time (ticks) */
 383                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 384
 385 #ifdef CONFIG_GENERIC_TIME
 386                 /* TSC halts in C2, so notify users */
 387                 mark_tsc_unstable();
 388 #endif
 389                 /* Re-enable interrupts */
 390                 local_irq_enable();
 391                 current_thread_info()->status |= TS_POLLING;
 392                 /* Compute time (ticks) that we were actually asleep */
 393                 sleep_ticks =
 394                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 395                 break;
 396
 397         case ACPI_STATE_C3:
 398
 399                 if (pr->flags.bm_check) {
 400                         if (atomic_inc_return(&c3_cpu_count) ==
 401                             num_online_cpus()) {
 402                                 /*
 403                                  * All CPUs are trying to go to C3
 404                                  * Disable bus master arbitration
 405                                  */
 406                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
 407                                                   ACPI_MTX_DO_NOT_LOCK);
 408                         }
 409                 } else {
 410                         /* SMP with no shared cache... Invalidate cache  */
 411                         ACPI_FLUSH_CPU_CACHE();
 412                 }
 413
 414                 /* Get start time (ticks) */
 415                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 416                 /* Invoke C3 */
 417                 acpi_cstate_enter(cx);
 418                 /* Get end time (ticks) */
 419                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 420                 if (pr->flags.bm_check) {
 421                         /* Enable bus master arbitration */
 422                         atomic_dec(&c3_cpu_count);
 423                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
 424                                           ACPI_MTX_DO_NOT_LOCK);
 425                 }
 426
 427 #ifdef CONFIG_GENERIC_TIME
 428                 /* TSC halts in C3, so notify users */
 429                 mark_tsc_unstable();
 430 #endif
 431                 /* Re-enable interrupts */
 432                 local_irq_enable();
 433                 current_thread_info()->status |= TS_POLLING;
 434                 /* Compute time (ticks) that we were actually asleep */
 435                 sleep_ticks =
 436                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 437                 break;
 438
 439         default:
 440                 local_irq_enable();
 441                 return;
 442         }
 443         cx->usage++;
 444         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 445                 cx->time += sleep_ticks;
 446
 447         next_state = pr->power.state;
 448
 449 #ifdef CONFIG_HOTPLUG_CPU
 450         /* Don't do promotion/demotion */
 451         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 452             !pr->flags.has_cst && !acpi_fadt.plvl2_up) {
 453                 next_state = cx;
 454                 goto end;
 455         }
 456 #endif
 457
 458         /*
 459          * Promotion?
 460          * ----------
 461          * Track the number of longs (time asleep is greater than threshold)
 462          * and promote when the count threshold is reached.  Note that bus
 463          * mastering activity may prevent promotions.
 464          * Do not promote above max_cstate.
 465          */
 466         if (cx->promotion.state &&
 467             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 468                 if (sleep_ticks > cx->promotion.threshold.ticks &&
 469                   cx->promotion.state->latency <= system_latency_constraint()) {
 470                         cx->promotion.count++;
 471                         cx->demotion.count = 0;
 472                         if (cx->promotion.count >=
 473                             cx->promotion.threshold.count) {
 474                                 if (pr->flags.bm_check) {
 475                                         if (!
 476                                             (pr->power.bm_activity & cx->
 477                                              promotion.threshold.bm)) {
 478                                                 next_state =
 479                                                     cx->promotion.state;
 480                                                 goto end;
 481                                         }
 482                                 } else {
 483                                         next_state = cx->promotion.state;
 484                                         goto end;
 485                                 }
 486                         }
 487                 }
 488         }
 489
 490         /*
 491          * Demotion?
 492          * ---------
 493          * Track the number of shorts (time asleep is less than time threshold)
 494          * and demote when the usage threshold is reached.
 495          */
 496         if (cx->demotion.state) {
 497                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 498                         cx->demotion.count++;
 499                         cx->promotion.count = 0;
 500                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 501                                 next_state = cx->demotion.state;
 502                                 goto end;
 503                         }
 504                 }
 505         }
 506
 507       end:
 508         /*
 509          * Demote if current state exceeds max_cstate
 510          * or if the latency of the current state is unacceptable
 511          */
 512         if ((pr->power.state - pr->power.states) > max_cstate ||
 513                 pr->power.state->latency > system_latency_constraint()) {
 514                 if (cx->demotion.state)
 515                         next_state = cx->demotion.state;
 516         }
 517
 518         /*
 519          * New Cx State?
 520          * -------------
 521          * If we're going to start using a new Cx state we must clean up
 522          * from the previous and prepare to use the new.
 523          */
 524         if (next_state != pr->power.state)
 525                 acpi_processor_power_activate(pr, next_state);
 526 }
 527
 528 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 529 {
 530         unsigned int i;
 531         unsigned int state_is_set = 0;
 532         struct acpi_processor_cx *lower = NULL;
 533         struct acpi_processor_cx *higher = NULL;
 534         struct acpi_processor_cx *cx;
 535
 536
 537         if (!pr)
 538                 return -EINVAL;
 539
 540         /*
 541          * This function sets the default Cx state policy (OS idle handler).
 542          * Our scheme is to promote quickly to C2 but more conservatively
 543          * to C3.  We're favoring C2  for its characteristics of low latency
 544          * (quick response), good power savings, and ability to allow bus
 545          * mastering activity.  Note that the Cx state policy is completely
 546          * customizable and can be altered dynamically.
 547          */
 548
 549         /* startup state */
 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 (!state_is_set)
 556                         pr->power.state = cx;
 557                 state_is_set++;
 558                 break;
 559         }
 560
 561         if (!state_is_set)
 562                 return -ENODEV;
 563
 564         /* demotion */
 565         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 566                 cx = &pr->power.states[i];
 567                 if (!cx->valid)
 568                         continue;
 569
 570                 if (lower) {
 571                         cx->demotion.state = lower;
 572                         cx->demotion.threshold.ticks = cx->latency_ticks;
 573                         cx->demotion.threshold.count = 1;
 574                         if (cx->type == ACPI_STATE_C3)
 575                                 cx->demotion.threshold.bm = bm_history;
 576                 }
 577
 578                 lower = cx;
 579         }
 580
 581         /* promotion */
 582         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 583                 cx = &pr->power.states[i];
 584                 if (!cx->valid)
 585                         continue;
 586
 587                 if (higher) {
 588                         cx->promotion.state = higher;
 589                         cx->promotion.threshold.ticks = cx->latency_ticks;
 590                         if (cx->type >= ACPI_STATE_C2)
 591                                 cx->promotion.threshold.count = 4;
 592                         else
 593                                 cx->promotion.threshold.count = 10;
 594                         if (higher->type == ACPI_STATE_C3)
 595                                 cx->promotion.threshold.bm = bm_history;
 596                 }
 597
 598                 higher = cx;
 599         }
 600
 601         return 0;
 602 }
 603
 604 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 605 {
 606
 607         if (!pr)
 608                 return -EINVAL;
 609
 610         if (!pr->pblk)
 611                 return -ENODEV;
 612
 613         /* if info is obtained from pblk/fadt, type equals state */
 614         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 615         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 616
 617 #ifndef CONFIG_HOTPLUG_CPU
 618         /*
 619          * Check for P_LVL2_UP flag before entering C2 and above on
 620          * an SMP system.
 621          */
 622         if ((num_online_cpus() > 1) && !acpi_fadt.plvl2_up)
 623                 return -ENODEV;
 624 #endif
 625
 626         /* determine C2 and C3 address from pblk */
 627         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 628         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 629
 630         /* determine latencies from FADT */
 631         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
 632         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
 633
 634         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 635                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 636                           pr->power.states[ACPI_STATE_C2].address,
 637                           pr->power.states[ACPI_STATE_C3].address));
 638
 639         return 0;
 640 }
 641
 642 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 643 {
 644         if (!pr->power.states[ACPI_STATE_C1].valid) {
 645                 /* set the first C-State to C1 */
 646                 /* all processors need to support C1 */
 647                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 648                 pr->power.states[ACPI_STATE_C1].valid = 1;
 649         }
 650         /* the C0 state only exists as a filler in our array */
 651         pr->power.states[ACPI_STATE_C0].valid = 1;
 652         return 0;
 653 }
 654
 655 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 656 {
 657         acpi_status status = 0;
 658         acpi_integer count;
 659         int current_count;
 660         int i;
 661         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 662         union acpi_object *cst;
 663
 664
 665         if (nocst)
 666                 return -ENODEV;
 667
 668         current_count = 0;
 669
 670         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 671         if (ACPI_FAILURE(status)) {
 672                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 673                 return -ENODEV;
 674         }
 675
 676         cst = (union acpi_object *)buffer.pointer;
 677
 678         /* There must be at least 2 elements */
 679         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 680                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 681                 status = -EFAULT;
 682                 goto end;
 683         }
 684
 685         count = cst->package.elements[0].integer.value;
 686
 687         /* Validate number of power states. */
 688         if (count < 1 || count != cst->package.count - 1) {
 689                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 690                 status = -EFAULT;
 691                 goto end;
 692         }
 693
 694         /* Tell driver that at least _CST is supported. */
 695         pr->flags.has_cst = 1;
 696
 697         for (i = 1; i <= count; i++) {
 698                 union acpi_object *element;
 699                 union acpi_object *obj;
 700                 struct acpi_power_register *reg;
 701                 struct acpi_processor_cx cx;
 702
 703                 memset(&cx, 0, sizeof(cx));
 704
 705                 element = (union acpi_object *)&(cst->package.elements[i]);
 706                 if (element->type != ACPI_TYPE_PACKAGE)
 707                         continue;
 708
 709                 if (element->package.count != 4)
 710                         continue;
 711
 712                 obj = (union acpi_object *)&(element->package.elements[0]);
 713
 714                 if (obj->type != ACPI_TYPE_BUFFER)
 715                         continue;
 716
 717                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 718
 719                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 720                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 721                         continue;
 722
 723                 /* There should be an easy way to extract an integer... */
 724                 obj = (union acpi_object *)&(element->package.elements[1]);
 725                 if (obj->type != ACPI_TYPE_INTEGER)
 726                         continue;
 727
 728                 cx.type = obj->integer.value;
 729                 /*
 730                  * Some buggy BIOSes won't list C1 in _CST -
 731                  * Let acpi_processor_get_power_info_default() handle them later
 732                  */
 733                 if (i == 1 && cx.type != ACPI_STATE_C1)
 734                         current_count++;
 735
 736                 cx.address = reg->address;
 737                 cx.index = current_count + 1;
 738
 739                 cx.space_id = ACPI_CSTATE_SYSTEMIO;
 740                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 741                         if (acpi_processor_ffh_cstate_probe
 742                                         (pr->id, &cx, reg) == 0) {
 743                                 cx.space_id = ACPI_CSTATE_FFH;
 744                         } else if (cx.type != ACPI_STATE_C1) {
 745                                 /*
 746                                  * C1 is a special case where FIXED_HARDWARE
 747                                  * can be handled in non-MWAIT way as well.
 748                                  * In that case, save this _CST entry info.
 749                                  * That is, we retain space_id of SYSTEM_IO for
 750                                  * halt based C1.
 751                                  * Otherwise, ignore this info and continue.
 752                                  */
 753                                 continue;
 754                         }
 755                 }
 756
 757                 obj = (union acpi_object *)&(element->package.elements[2]);
 758                 if (obj->type != ACPI_TYPE_INTEGER)
 759                         continue;
 760
 761                 cx.latency = obj->integer.value;
 762
 763                 obj = (union acpi_object *)&(element->package.elements[3]);
 764                 if (obj->type != ACPI_TYPE_INTEGER)
 765                         continue;
 766
 767                 cx.power = obj->integer.value;
 768
 769                 current_count++;
 770                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 771
 772                 /*
 773                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 774                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 775                  */
 776                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 777                         printk(KERN_WARNING
 778                                "Limiting number of power states to max (%d)\n",
 779                                ACPI_PROCESSOR_MAX_POWER);
 780                         printk(KERN_WARNING
 781                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 782                         break;
 783                 }
 784         }
 785
 786         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 787                           current_count));
 788
 789         /* Validate number of power states discovered */
 790         if (current_count < 2)
 791                 status = -EFAULT;
 792
 793       end:
 794         kfree(buffer.pointer);
 795
 796         return status;
 797 }
 798
 799 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 800 {
 801
 802         if (!cx->address)
 803                 return;
 804
 805         /*
 806          * C2 latency must be less than or equal to 100
 807          * microseconds.
 808          */
 809         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 810                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 811                                   "latency too large [%d]\n", cx->latency));
 812                 return;
 813         }
 814
 815         /*
 816          * Otherwise we've met all of our C2 requirements.
 817          * Normalize the C2 latency to expidite policy
 818          */
 819         cx->valid = 1;
 820         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 821
 822         return;
 823 }
 824
 825 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 826                                            struct acpi_processor_cx *cx)
 827 {
 828         static int bm_check_flag;
 829
 830
 831         if (!cx->address)
 832                 return;
 833
 834         /*
 835          * C3 latency must be less than or equal to 1000
 836          * microseconds.
 837          */
 838         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 839                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 840                                   "latency too large [%d]\n", cx->latency));
 841                 return;
 842         }
 843
 844         /*
 845          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 846          * DMA transfers are used by any ISA device to avoid livelock.
 847          * Note that we could disable Type-F DMA (as recommended by
 848          * the erratum), but this is known to disrupt certain ISA
 849          * devices thus we take the conservative approach.
 850          */
 851         else if (errata.piix4.fdma) {
 852                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 853                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 854                 return;
 855         }
 856
 857         /* All the logic here assumes flags.bm_check is same across all CPUs */
 858         if (!bm_check_flag) {
 859                 /* Determine whether bm_check is needed based on CPU  */
 860                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 861                 bm_check_flag = pr->flags.bm_check;
 862         } else {
 863                 pr->flags.bm_check = bm_check_flag;
 864         }
 865
 866         if (pr->flags.bm_check) {
 867                 /* bus mastering control is necessary */
 868                 if (!pr->flags.bm_control) {
 869                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 870                                           "C3 support requires bus mastering control\n"));
 871                         return;
 872                 }
 873         } else {
 874                 /*
 875                  * WBINVD should be set in fadt, for C3 state to be
 876                  * supported on when bm_check is not required.
 877                  */
 878                 if (acpi_fadt.wb_invd != 1) {
 879                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 880                                           "Cache invalidation should work properly"
 881                                           " for C3 to be enabled on SMP systems\n"));
 882                         return;
 883                 }
 884                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
 885                                   0, ACPI_MTX_DO_NOT_LOCK);
 886         }
 887
 888         /*
 889          * Otherwise we've met all of our C3 requirements.
 890          * Normalize the C3 latency to expidite policy.  Enable
 891          * checking of bus mastering status (bm_check) so we can
 892          * use this in our C3 policy
 893          */
 894         cx->valid = 1;
 895         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 896
 897         return;
 898 }
 899
 900 static int acpi_processor_power_verify(struct acpi_processor *pr)
 901 {
 902         unsigned int i;
 903         unsigned int working = 0;
 904
 905 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 906         int timer_broadcast = 0;
 907         cpumask_t mask = cpumask_of_cpu(pr->id);
 908         on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
 909 #endif
 910
 911         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 912                 struct acpi_processor_cx *cx = &pr->power.states[i];
 913
 914                 switch (cx->type) {
 915                 case ACPI_STATE_C1:
 916                         cx->valid = 1;
 917                         break;
 918
 919                 case ACPI_STATE_C2:
 920                         acpi_processor_power_verify_c2(cx);
 921 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 922                         /* Some AMD systems fake C3 as C2, but still
 923                            have timer troubles */
 924                         if (cx->valid &&
 925                                 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
 926                                 timer_broadcast++;
 927 #endif
 928                         break;
 929
 930                 case ACPI_STATE_C3:
 931                         acpi_processor_power_verify_c3(pr, cx);
 932 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 933                         if (cx->valid)
 934                                 timer_broadcast++;
 935 #endif
 936                         break;
 937                 }
 938
 939                 if (cx->valid)
 940                         working++;
 941         }
 942
 943 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 944         if (timer_broadcast)
 945                 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
 946 #endif
 947
 948         return (working);
 949 }
 950
 951 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 952 {
 953         unsigned int i;
 954         int result;
 955
 956
 957         /* NOTE: the idle thread may not be running while calling
 958          * this function */
 959
 960         /* Zero initialize all the C-states info. */
 961         memset(pr->power.states, 0, sizeof(pr->power.states));
 962
 963         result = acpi_processor_get_power_info_cst(pr);
 964         if (result == -ENODEV)
 965                 result = acpi_processor_get_power_info_fadt(pr);
 966
 967         if (result)
 968                 return result;
 969
 970         acpi_processor_get_power_info_default(pr);
 971
 972         pr->power.count = acpi_processor_power_verify(pr);
 973
 974         /*
 975          * Set Default Policy
 976          * ------------------
 977          * Now that we know which states are supported, set the default
 978          * policy.  Note that this policy can be changed dynamically
 979          * (e.g. encourage deeper sleeps to conserve battery life when
 980          * not on AC).
 981          */
 982         result = acpi_processor_set_power_policy(pr);
 983         if (result)
 984                 return result;
 985
 986         /*
 987          * if one state of type C2 or C3 is available, mark this
 988          * CPU as being "idle manageable"
 989          */
 990         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 991                 if (pr->power.states[i].valid) {
 992                         pr->power.count = i;
 993                         if (pr->power.states[i].type >= ACPI_STATE_C2)
 994                                 pr->flags.power = 1;
 995                 }
 996         }
 997
 998         return 0;
 999 }
1000
1001 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1002 {
1003         int result = 0;
1004
1005
1006         if (!pr)
1007                 return -EINVAL;
1008
1009         if (nocst) {
1010                 return -ENODEV;
1011         }
1012
1013         if (!pr->flags.power_setup_done)
1014                 return -ENODEV;
1015
1016         /* Fall back to the default idle loop */
1017         pm_idle = pm_idle_save;
1018         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
1019
1020         pr->flags.power = 0;
1021         result = acpi_processor_get_power_info(pr);
1022         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1023                 pm_idle = acpi_processor_idle;
1024
1025         return result;
1026 }
1027
1028 /* proc interface */
1029
1030 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1031 {
1032         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
1033         unsigned int i;
1034
1035
1036         if (!pr)
1037                 goto end;
1038
1039         seq_printf(seq, "active state:            C%zd\n"
1040                    "max_cstate:              C%d\n"
1041                    "bus master activity:     %08x\n"
1042                    "maximum allowed latency: %d usec\n",
1043                    pr->power.state ? pr->power.state - pr->power.states : 0,
1044                    max_cstate, (unsigned)pr->power.bm_activity,
1045                    system_latency_constraint());
1046
1047         seq_puts(seq, "states:\n");
1048
1049         for (i = 1; i <= pr->power.count; i++) {
1050                 seq_printf(seq, "   %cC%d:                  ",
1051                            (&pr->power.states[i] ==
1052                             pr->power.state ? '*' : ' '), i);
1053
1054                 if (!pr->power.states[i].valid) {
1055                         seq_puts(seq, "<not supported>\n");
1056                         continue;
1057                 }
1058
1059                 switch (pr->power.states[i].type) {
1060                 case ACPI_STATE_C1:
1061                         seq_printf(seq, "type[C1] ");
1062                         break;
1063                 case ACPI_STATE_C2:
1064                         seq_printf(seq, "type[C2] ");
1065                         break;
1066                 case ACPI_STATE_C3:
1067                         seq_printf(seq, "type[C3] ");
1068                         break;
1069                 default:
1070                         seq_printf(seq, "type[--] ");
1071                         break;
1072                 }
1073
1074                 if (pr->power.states[i].promotion.state)
1075                         seq_printf(seq, "promotion[C%zd] ",
1076                                    (pr->power.states[i].promotion.state -
1077                                     pr->power.states));
1078                 else
1079                         seq_puts(seq, "promotion[--] ");
1080
1081                 if (pr->power.states[i].demotion.state)
1082                         seq_printf(seq, "demotion[C%zd] ",
1083                                    (pr->power.states[i].demotion.state -
1084                                     pr->power.states));
1085                 else
1086                         seq_puts(seq, "demotion[--] ");
1087
1088                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1089                            pr->power.states[i].latency,
1090                            pr->power.states[i].usage,
1091                            pr->power.states[i].time);
1092         }
1093
1094       end:
1095         return 0;
1096 }
1097
1098 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1099 {
1100         return single_open(file, acpi_processor_power_seq_show,
1101                            PDE(inode)->data);
1102 }
1103
1104 static const struct file_operations acpi_processor_power_fops = {
1105         .open = acpi_processor_power_open_fs,
1106         .read = seq_read,
1107         .llseek = seq_lseek,
1108         .release = single_release,
1109 };
1110
1111 #ifdef CONFIG_SMP
1112 static void smp_callback(void *v)
1113 {
1114         /* we already woke the CPU up, nothing more to do */
1115 }
1116
1117 /*
1118  * This function gets called when a part of the kernel has a new latency
1119  * requirement.  This means we need to get all processors out of their C-state,
1120  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1121  * wakes them all right up.
1122  */
1123 static int acpi_processor_latency_notify(struct notifier_block *b,
1124                 unsigned long l, void *v)
1125 {
1126         smp_call_function(smp_callback, NULL, 0, 1);
1127         return NOTIFY_OK;
1128 }
1129
1130 static struct notifier_block acpi_processor_latency_notifier = {
1131         .notifier_call = acpi_processor_latency_notify,
1132 };
1133 #endif
1134
1135 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1136                               struct acpi_device *device)
1137 {
1138         acpi_status status = 0;
1139         static int first_run;
1140         struct proc_dir_entry *entry = NULL;
1141         unsigned int i;
1142
1143
1144         if (!first_run) {
1145                 dmi_check_system(processor_power_dmi_table);
1146                 if (max_cstate < ACPI_C_STATES_MAX)
1147                         printk(KERN_NOTICE
1148                                "ACPI: processor limited to max C-state %d\n",
1149                                max_cstate);
1150                 first_run++;
1151 #ifdef CONFIG_SMP
1152                 register_latency_notifier(&acpi_processor_latency_notifier);
1153 #endif
1154         }
1155
1156         if (!pr)
1157                 return -EINVAL;
1158
1159         if (acpi_fadt.cst_cnt && !nocst) {
1160                 status =
1161                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1162                 if (ACPI_FAILURE(status)) {
1163                         ACPI_EXCEPTION((AE_INFO, status,
1164                                         "Notifying BIOS of _CST ability failed"));
1165                 }
1166         }
1167
1168         acpi_processor_get_power_info(pr);
1169
1170         /*
1171          * Install the idle handler if processor power management is supported.
1172          * Note that we use previously set idle handler will be used on
1173          * platforms that only support C1.
1174          */
1175         if ((pr->flags.power) && (!boot_option_idle_override)) {
1176                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1177                 for (i = 1; i <= pr->power.count; i++)
1178                         if (pr->power.states[i].valid)
1179                                 printk(" C%d[C%d]", i,
1180                                        pr->power.states[i].type);
1181                 printk(")\n");
1182
1183                 if (pr->id == 0) {
1184                         pm_idle_save = pm_idle;
1185                         pm_idle = acpi_processor_idle;
1186                 }
1187         }
1188
1189         /* 'power' [R] */
1190         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1191                                   S_IRUGO, acpi_device_dir(device));
1192         if (!entry)
1193                 return -EIO;
1194         else {
1195                 entry->proc_fops = &acpi_processor_power_fops;
1196                 entry->data = acpi_driver_data(device);
1197                 entry->owner = THIS_MODULE;
1198         }
1199
1200         pr->flags.power_setup_done = 1;
1201
1202         return 0;
1203 }
1204
1205 int acpi_processor_power_exit(struct acpi_processor *pr,
1206                               struct acpi_device *device)
1207 {
1208
1209         pr->flags.power_setup_done = 0;
1210
1211         if (acpi_device_dir(device))
1212                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1213                                   acpi_device_dir(device));
1214
1215         /* Unregister the idle handler when processor #0 is removed. */
1216         if (pr->id == 0) {
1217                 pm_idle = pm_idle_save;
1218
1219                 /*
1220                  * We are about to unload the current idle thread pm callback
1221                  * (pm_idle), Wait for all processors to update cached/local
1222                  * copies of pm_idle before proceeding.
1223                  */
1224                 cpu_idle_wait();
1225 #ifdef CONFIG_SMP
1226                 unregister_latency_notifier(&acpi_processor_latency_notifier);
1227 #endif
1228         }
1229
1230         return 0;
1231 }