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_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 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                         break;
 192                 }
 193         }
 194
 195         /* Prepare to use new state. */
 196         switch (new->type) {
 197         case ACPI_STATE_C3:
 198                 /* Enable bus master reload */
 199                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 200                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 201                 break;
 202         }
 203
 204         pr->power.state = new;
 205
 206         return;
 207 }
 208
 209 static void acpi_safe_halt(void)
 210 {
 211         current_thread_info()->status &= ~TS_POLLING;
 212         /*
 213          * TS_POLLING-cleared state must be visible before we
 214          * test NEED_RESCHED:
 215          */
 216         smp_mb();
 217         if (!need_resched())
 218                 safe_halt();
 219         current_thread_info()->status |= TS_POLLING;
 220 }
 221
 222 static atomic_t c3_cpu_count;
 223
 224 /* Common C-state entry for C2, C3, .. */
 225 static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
 226 {
 227         if (cstate->space_id == ACPI_CSTATE_FFH) {
 228                 /* Call into architectural FFH based C-state */
 229                 acpi_processor_ffh_cstate_enter(cstate);
 230         } else {
 231                 int unused;
 232                 /* IO port based C-state */
 233                 inb(cstate->address);
 234                 /* Dummy wait op - must do something useless after P_LVL2 read
 235                    because chipsets cannot guarantee that STPCLK# signal
 236                    gets asserted in time to freeze execution properly. */
 237                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
 238         }
 239 }
 240
 241 static void acpi_processor_idle(void)
 242 {
 243         struct acpi_processor *pr = NULL;
 244         struct acpi_processor_cx *cx = NULL;
 245         struct acpi_processor_cx *next_state = NULL;
 246         int sleep_ticks = 0;
 247         u32 t1, t2 = 0;
 248
 249         pr = processors[smp_processor_id()];
 250         if (!pr)
 251                 return;
 252
 253         /*
 254          * Interrupts must be disabled during bus mastering calculations and
 255          * for C2/C3 transitions.
 256          */
 257         local_irq_disable();
 258
 259         /*
 260          * Check whether we truly need to go idle, or should
 261          * reschedule:
 262          */
 263         if (unlikely(need_resched())) {
 264                 local_irq_enable();
 265                 return;
 266         }
 267
 268         cx = pr->power.state;
 269         if (!cx) {
 270                 if (pm_idle_save)
 271                         pm_idle_save();
 272                 else
 273                         acpi_safe_halt();
 274                 return;
 275         }
 276
 277         /*
 278          * Check BM Activity
 279          * -----------------
 280          * Check for bus mastering activity (if required), record, and check
 281          * for demotion.
 282          */
 283         if (pr->flags.bm_check) {
 284                 u32 bm_status = 0;
 285                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 286
 287                 if (diff > 31)
 288                         diff = 31;
 289
 290                 pr->power.bm_activity <<= diff;
 291
 292                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 293                 if (bm_status) {
 294                         pr->power.bm_activity |= 0x1;
 295                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 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_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 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                 /*
 349                  * TS_POLLING-cleared state must be visible before we
 350                  * test NEED_RESCHED:
 351                  */
 352                 smp_mb();
 353                 if (need_resched()) {
 354                         current_thread_info()->status |= TS_POLLING;
 355                         local_irq_enable();
 356                         return;
 357                 }
 358         }
 359
 360         switch (cx->type) {
 361
 362         case ACPI_STATE_C1:
 363                 /*
 364                  * Invoke C1.
 365                  * Use the appropriate idle routine, the one that would
 366                  * be used without acpi C-states.
 367                  */
 368                 if (pm_idle_save)
 369                         pm_idle_save();
 370                 else
 371                         acpi_safe_halt();
 372
 373                 /*
 374                  * TBD: Can't get time duration while in C1, as resumes
 375                  *      go to an ISR rather than here.  Need to instrument
 376                  *      base interrupt handler.
 377                  */
 378                 sleep_ticks = 0xFFFFFFFF;
 379                 break;
 380
 381         case ACPI_STATE_C2:
 382                 /* Get start time (ticks) */
 383                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 384                 /* Invoke C2 */
 385                 acpi_cstate_enter(cx);
 386                 /* Get end time (ticks) */
 387                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 388
 389 #ifdef CONFIG_GENERIC_TIME
 390                 /* TSC halts in C2, so notify users */
 391                 mark_tsc_unstable();
 392 #endif
 393                 /* Re-enable interrupts */
 394                 local_irq_enable();
 395                 current_thread_info()->status |= TS_POLLING;
 396                 /* Compute time (ticks) that we were actually asleep */
 397                 sleep_ticks =
 398                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 399                 break;
 400
 401         case ACPI_STATE_C3:
 402
 403                 if (pr->flags.bm_check) {
 404                         if (atomic_inc_return(&c3_cpu_count) ==
 405                             num_online_cpus()) {
 406                                 /*
 407                                  * All CPUs are trying to go to C3
 408                                  * Disable bus master arbitration
 409                                  */
 410                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
 411                         }
 412                 } else {
 413                         /* SMP with no shared cache... Invalidate cache  */
 414                         ACPI_FLUSH_CPU_CACHE();
 415                 }
 416
 417                 /* Get start time (ticks) */
 418                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 419                 /* Invoke C3 */
 420                 acpi_cstate_enter(cx);
 421                 /* Get end time (ticks) */
 422                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 423                 if (pr->flags.bm_check) {
 424                         /* Enable bus master arbitration */
 425                         atomic_dec(&c3_cpu_count);
 426                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
 427                 }
 428
 429 #ifdef CONFIG_GENERIC_TIME
 430                 /* TSC halts in C3, so notify users */
 431                 mark_tsc_unstable();
 432 #endif
 433                 /* Re-enable interrupts */
 434                 local_irq_enable();
 435                 current_thread_info()->status |= TS_POLLING;
 436                 /* Compute time (ticks) that we were actually asleep */
 437                 sleep_ticks =
 438                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 439                 break;
 440
 441         default:
 442                 local_irq_enable();
 443                 return;
 444         }
 445         cx->usage++;
 446         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 447                 cx->time += sleep_ticks;
 448
 449         next_state = pr->power.state;
 450
 451 #ifdef CONFIG_HOTPLUG_CPU
 452         /* Don't do promotion/demotion */
 453         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 454             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
 455                 next_state = cx;
 456                 goto end;
 457         }
 458 #endif
 459
 460         /*
 461          * Promotion?
 462          * ----------
 463          * Track the number of longs (time asleep is greater than threshold)
 464          * and promote when the count threshold is reached.  Note that bus
 465          * mastering activity may prevent promotions.
 466          * Do not promote above max_cstate.
 467          */
 468         if (cx->promotion.state &&
 469             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 470                 if (sleep_ticks > cx->promotion.threshold.ticks &&
 471                   cx->promotion.state->latency <= system_latency_constraint()) {
 472                         cx->promotion.count++;
 473                         cx->demotion.count = 0;
 474                         if (cx->promotion.count >=
 475                             cx->promotion.threshold.count) {
 476                                 if (pr->flags.bm_check) {
 477                                         if (!
 478                                             (pr->power.bm_activity & cx->
 479                                              promotion.threshold.bm)) {
 480                                                 next_state =
 481                                                     cx->promotion.state;
 482                                                 goto end;
 483                                         }
 484                                 } else {
 485                                         next_state = cx->promotion.state;
 486                                         goto end;
 487                                 }
 488                         }
 489                 }
 490         }
 491
 492         /*
 493          * Demotion?
 494          * ---------
 495          * Track the number of shorts (time asleep is less than time threshold)
 496          * and demote when the usage threshold is reached.
 497          */
 498         if (cx->demotion.state) {
 499                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 500                         cx->demotion.count++;
 501                         cx->promotion.count = 0;
 502                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 503                                 next_state = cx->demotion.state;
 504                                 goto end;
 505                         }
 506                 }
 507         }
 508
 509       end:
 510         /*
 511          * Demote if current state exceeds max_cstate
 512          * or if the latency of the current state is unacceptable
 513          */
 514         if ((pr->power.state - pr->power.states) > max_cstate ||
 515                 pr->power.state->latency > system_latency_constraint()) {
 516                 if (cx->demotion.state)
 517                         next_state = cx->demotion.state;
 518         }
 519
 520         /*
 521          * New Cx State?
 522          * -------------
 523          * If we're going to start using a new Cx state we must clean up
 524          * from the previous and prepare to use the new.
 525          */
 526         if (next_state != pr->power.state)
 527                 acpi_processor_power_activate(pr, next_state);
 528 }
 529
 530 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 531 {
 532         unsigned int i;
 533         unsigned int state_is_set = 0;
 534         struct acpi_processor_cx *lower = NULL;
 535         struct acpi_processor_cx *higher = NULL;
 536         struct acpi_processor_cx *cx;
 537
 538
 539         if (!pr)
 540                 return -EINVAL;
 541
 542         /*
 543          * This function sets the default Cx state policy (OS idle handler).
 544          * Our scheme is to promote quickly to C2 but more conservatively
 545          * to C3.  We're favoring C2  for its characteristics of low latency
 546          * (quick response), good power savings, and ability to allow bus
 547          * mastering activity.  Note that the Cx state policy is completely
 548          * customizable and can be altered dynamically.
 549          */
 550
 551         /* startup state */
 552         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 553                 cx = &pr->power.states[i];
 554                 if (!cx->valid)
 555                         continue;
 556
 557                 if (!state_is_set)
 558                         pr->power.state = cx;
 559                 state_is_set++;
 560                 break;
 561         }
 562
 563         if (!state_is_set)
 564                 return -ENODEV;
 565
 566         /* demotion */
 567         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 568                 cx = &pr->power.states[i];
 569                 if (!cx->valid)
 570                         continue;
 571
 572                 if (lower) {
 573                         cx->demotion.state = lower;
 574                         cx->demotion.threshold.ticks = cx->latency_ticks;
 575                         cx->demotion.threshold.count = 1;
 576                         if (cx->type == ACPI_STATE_C3)
 577                                 cx->demotion.threshold.bm = bm_history;
 578                 }
 579
 580                 lower = cx;
 581         }
 582
 583         /* promotion */
 584         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 585                 cx = &pr->power.states[i];
 586                 if (!cx->valid)
 587                         continue;
 588
 589                 if (higher) {
 590                         cx->promotion.state = higher;
 591                         cx->promotion.threshold.ticks = cx->latency_ticks;
 592                         if (cx->type >= ACPI_STATE_C2)
 593                                 cx->promotion.threshold.count = 4;
 594                         else
 595                                 cx->promotion.threshold.count = 10;
 596                         if (higher->type == ACPI_STATE_C3)
 597                                 cx->promotion.threshold.bm = bm_history;
 598                 }
 599
 600                 higher = cx;
 601         }
 602
 603         return 0;
 604 }
 605
 606 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 607 {
 608
 609         if (!pr)
 610                 return -EINVAL;
 611
 612         if (!pr->pblk)
 613                 return -ENODEV;
 614
 615         /* if info is obtained from pblk/fadt, type equals state */
 616         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 617         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 618
 619 #ifndef CONFIG_HOTPLUG_CPU
 620         /*
 621          * Check for P_LVL2_UP flag before entering C2 and above on
 622          * an SMP system.
 623          */
 624         if ((num_online_cpus() > 1) &&
 625             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 626                 return -ENODEV;
 627 #endif
 628
 629         /* determine C2 and C3 address from pblk */
 630         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 631         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 632
 633         /* determine latencies from FADT */
 634         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency;
 635         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency;
 636
 637         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 638                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 639                           pr->power.states[ACPI_STATE_C2].address,
 640                           pr->power.states[ACPI_STATE_C3].address));
 641
 642         return 0;
 643 }
 644
 645 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 646 {
 647         if (!pr->power.states[ACPI_STATE_C1].valid) {
 648                 /* set the first C-State to C1 */
 649                 /* all processors need to support C1 */
 650                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 651                 pr->power.states[ACPI_STATE_C1].valid = 1;
 652         }
 653         /* the C0 state only exists as a filler in our array */
 654         pr->power.states[ACPI_STATE_C0].valid = 1;
 655         return 0;
 656 }
 657
 658 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 659 {
 660         acpi_status status = 0;
 661         acpi_integer count;
 662         int current_count;
 663         int i;
 664         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 665         union acpi_object *cst;
 666
 667
 668         if (nocst)
 669                 return -ENODEV;
 670
 671         current_count = 0;
 672
 673         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 674         if (ACPI_FAILURE(status)) {
 675                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 676                 return -ENODEV;
 677         }
 678
 679         cst = buffer.pointer;
 680
 681         /* There must be at least 2 elements */
 682         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 683                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 684                 status = -EFAULT;
 685                 goto end;
 686         }
 687
 688         count = cst->package.elements[0].integer.value;
 689
 690         /* Validate number of power states. */
 691         if (count < 1 || count != cst->package.count - 1) {
 692                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 693                 status = -EFAULT;
 694                 goto end;
 695         }
 696
 697         /* Tell driver that at least _CST is supported. */
 698         pr->flags.has_cst = 1;
 699
 700         for (i = 1; i <= count; i++) {
 701                 union acpi_object *element;
 702                 union acpi_object *obj;
 703                 struct acpi_power_register *reg;
 704                 struct acpi_processor_cx cx;
 705
 706                 memset(&cx, 0, sizeof(cx));
 707
 708                 element = &(cst->package.elements[i]);
 709                 if (element->type != ACPI_TYPE_PACKAGE)
 710                         continue;
 711
 712                 if (element->package.count != 4)
 713                         continue;
 714
 715                 obj = &(element->package.elements[0]);
 716
 717                 if (obj->type != ACPI_TYPE_BUFFER)
 718                         continue;
 719
 720                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 721
 722                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 723                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 724                         continue;
 725
 726                 /* There should be an easy way to extract an integer... */
 727                 obj = &(element->package.elements[1]);
 728                 if (obj->type != ACPI_TYPE_INTEGER)
 729                         continue;
 730
 731                 cx.type = obj->integer.value;
 732                 /*
 733                  * Some buggy BIOSes won't list C1 in _CST -
 734                  * Let acpi_processor_get_power_info_default() handle them later
 735                  */
 736                 if (i == 1 && cx.type != ACPI_STATE_C1)
 737                         current_count++;
 738
 739                 cx.address = reg->address;
 740                 cx.index = current_count + 1;
 741
 742                 cx.space_id = ACPI_CSTATE_SYSTEMIO;
 743                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 744                         if (acpi_processor_ffh_cstate_probe
 745                                         (pr->id, &cx, reg) == 0) {
 746                                 cx.space_id = ACPI_CSTATE_FFH;
 747                         } else if (cx.type != ACPI_STATE_C1) {
 748                                 /*
 749                                  * C1 is a special case where FIXED_HARDWARE
 750                                  * can be handled in non-MWAIT way as well.
 751                                  * In that case, save this _CST entry info.
 752                                  * That is, we retain space_id of SYSTEM_IO for
 753                                  * halt based C1.
 754                                  * Otherwise, ignore this info and continue.
 755                                  */
 756                                 continue;
 757                         }
 758                 }
 759
 760                 obj = &(element->package.elements[2]);
 761                 if (obj->type != ACPI_TYPE_INTEGER)
 762                         continue;
 763
 764                 cx.latency = obj->integer.value;
 765
 766                 obj = &(element->package.elements[3]);
 767                 if (obj->type != ACPI_TYPE_INTEGER)
 768                         continue;
 769
 770                 cx.power = obj->integer.value;
 771
 772                 current_count++;
 773                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 774
 775                 /*
 776                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 777                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 778                  */
 779                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 780                         printk(KERN_WARNING
 781                                "Limiting number of power states to max (%d)\n",
 782                                ACPI_PROCESSOR_MAX_POWER);
 783                         printk(KERN_WARNING
 784                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 785                         break;
 786                 }
 787         }
 788
 789         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 790                           current_count));
 791
 792         /* Validate number of power states discovered */
 793         if (current_count < 2)
 794                 status = -EFAULT;
 795
 796       end:
 797         kfree(buffer.pointer);
 798
 799         return status;
 800 }
 801
 802 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 803 {
 804
 805         if (!cx->address)
 806                 return;
 807
 808         /*
 809          * C2 latency must be less than or equal to 100
 810          * microseconds.
 811          */
 812         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 813                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 814                                   "latency too large [%d]\n", cx->latency));
 815                 return;
 816         }
 817
 818         /*
 819          * Otherwise we've met all of our C2 requirements.
 820          * Normalize the C2 latency to expidite policy
 821          */
 822         cx->valid = 1;
 823         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 824
 825         return;
 826 }
 827
 828 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 829                                            struct acpi_processor_cx *cx)
 830 {
 831         static int bm_check_flag;
 832
 833
 834         if (!cx->address)
 835                 return;
 836
 837         /*
 838          * C3 latency must be less than or equal to 1000
 839          * microseconds.
 840          */
 841         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 842                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 843                                   "latency too large [%d]\n", cx->latency));
 844                 return;
 845         }
 846
 847         /*
 848          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 849          * DMA transfers are used by any ISA device to avoid livelock.
 850          * Note that we could disable Type-F DMA (as recommended by
 851          * the erratum), but this is known to disrupt certain ISA
 852          * devices thus we take the conservative approach.
 853          */
 854         else if (errata.piix4.fdma) {
 855                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 856                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 857                 return;
 858         }
 859
 860         /* All the logic here assumes flags.bm_check is same across all CPUs */
 861         if (!bm_check_flag) {
 862                 /* Determine whether bm_check is needed based on CPU  */
 863                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 864                 bm_check_flag = pr->flags.bm_check;
 865         } else {
 866                 pr->flags.bm_check = bm_check_flag;
 867         }
 868
 869         if (pr->flags.bm_check) {
 870                 /* bus mastering control is necessary */
 871                 if (!pr->flags.bm_control) {
 872                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 873                                           "C3 support requires bus mastering control\n"));
 874                         return;
 875                 }
 876         } else {
 877                 /*
 878                  * WBINVD should be set in fadt, for C3 state to be
 879                  * supported on when bm_check is not required.
 880                  */
 881                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 882                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 883                                           "Cache invalidation should work properly"
 884                                           " for C3 to be enabled on SMP systems\n"));
 885                         return;
 886                 }
 887                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 888         }
 889
 890         /*
 891          * Otherwise we've met all of our C3 requirements.
 892          * Normalize the C3 latency to expidite policy.  Enable
 893          * checking of bus mastering status (bm_check) so we can
 894          * use this in our C3 policy
 895          */
 896         cx->valid = 1;
 897         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 898
 899         return;
 900 }
 901
 902 static int acpi_processor_power_verify(struct acpi_processor *pr)
 903 {
 904         unsigned int i;
 905         unsigned int working = 0;
 906
 907 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 908         int timer_broadcast = 0;
 909         cpumask_t mask = cpumask_of_cpu(pr->id);
 910         on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
 911 #endif
 912
 913         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 914                 struct acpi_processor_cx *cx = &pr->power.states[i];
 915
 916                 switch (cx->type) {
 917                 case ACPI_STATE_C1:
 918                         cx->valid = 1;
 919                         break;
 920
 921                 case ACPI_STATE_C2:
 922                         acpi_processor_power_verify_c2(cx);
 923 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 924                         /* Some AMD systems fake C3 as C2, but still
 925                            have timer troubles */
 926                         if (cx->valid &&
 927                                 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
 928                                 timer_broadcast++;
 929 #endif
 930                         break;
 931
 932                 case ACPI_STATE_C3:
 933                         acpi_processor_power_verify_c3(pr, cx);
 934 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 935                         if (cx->valid)
 936                                 timer_broadcast++;
 937 #endif
 938                         break;
 939                 }
 940
 941                 if (cx->valid)
 942                         working++;
 943         }
 944
 945 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 946         if (timer_broadcast)
 947                 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
 948 #endif
 949
 950         return (working);
 951 }
 952
 953 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 954 {
 955         unsigned int i;
 956         int result;
 957
 958
 959         /* NOTE: the idle thread may not be running while calling
 960          * this function */
 961
 962         /* Zero initialize all the C-states info. */
 963         memset(pr->power.states, 0, sizeof(pr->power.states));
 964
 965         result = acpi_processor_get_power_info_cst(pr);
 966         if (result == -ENODEV)
 967                 result = acpi_processor_get_power_info_fadt(pr);
 968
 969         if (result)
 970                 return result;
 971
 972         acpi_processor_get_power_info_default(pr);
 973
 974         pr->power.count = acpi_processor_power_verify(pr);
 975
 976         /*
 977          * Set Default Policy
 978          * ------------------
 979          * Now that we know which states are supported, set the default
 980          * policy.  Note that this policy can be changed dynamically
 981          * (e.g. encourage deeper sleeps to conserve battery life when
 982          * not on AC).
 983          */
 984         result = acpi_processor_set_power_policy(pr);
 985         if (result)
 986                 return result;
 987
 988         /*
 989          * if one state of type C2 or C3 is available, mark this
 990          * CPU as being "idle manageable"
 991          */
 992         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 993                 if (pr->power.states[i].valid) {
 994                         pr->power.count = i;
 995                         if (pr->power.states[i].type >= ACPI_STATE_C2)
 996                                 pr->flags.power = 1;
 997                 }
 998         }
 999
1000         return 0;
1001 }
1002
1003 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1004 {
1005         int result = 0;
1006
1007
1008         if (!pr)
1009                 return -EINVAL;
1010
1011         if (nocst) {
1012                 return -ENODEV;
1013         }
1014
1015         if (!pr->flags.power_setup_done)
1016                 return -ENODEV;
1017
1018         /* Fall back to the default idle loop */
1019         pm_idle = pm_idle_save;
1020         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
1021
1022         pr->flags.power = 0;
1023         result = acpi_processor_get_power_info(pr);
1024         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1025                 pm_idle = acpi_processor_idle;
1026
1027         return result;
1028 }
1029
1030 /* proc interface */
1031
1032 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1033 {
1034         struct acpi_processor *pr = seq->private;
1035         unsigned int i;
1036
1037
1038         if (!pr)
1039                 goto end;
1040
1041         seq_printf(seq, "active state:            C%zd\n"
1042                    "max_cstate:              C%d\n"
1043                    "bus master activity:     %08x\n"
1044                    "maximum allowed latency: %d usec\n",
1045                    pr->power.state ? pr->power.state - pr->power.states : 0,
1046                    max_cstate, (unsigned)pr->power.bm_activity,
1047                    system_latency_constraint());
1048
1049         seq_puts(seq, "states:\n");
1050
1051         for (i = 1; i <= pr->power.count; i++) {
1052                 seq_printf(seq, "   %cC%d:                  ",
1053                            (&pr->power.states[i] ==
1054                             pr->power.state ? '*' : ' '), i);
1055
1056                 if (!pr->power.states[i].valid) {
1057                         seq_puts(seq, "<not supported>\n");
1058                         continue;
1059                 }
1060
1061                 switch (pr->power.states[i].type) {
1062                 case ACPI_STATE_C1:
1063                         seq_printf(seq, "type[C1] ");
1064                         break;
1065                 case ACPI_STATE_C2:
1066                         seq_printf(seq, "type[C2] ");
1067                         break;
1068                 case ACPI_STATE_C3:
1069                         seq_printf(seq, "type[C3] ");
1070                         break;
1071                 default:
1072                         seq_printf(seq, "type[--] ");
1073                         break;
1074                 }
1075
1076                 if (pr->power.states[i].promotion.state)
1077                         seq_printf(seq, "promotion[C%zd] ",
1078                                    (pr->power.states[i].promotion.state -
1079                                     pr->power.states));
1080                 else
1081                         seq_puts(seq, "promotion[--] ");
1082
1083                 if (pr->power.states[i].demotion.state)
1084                         seq_printf(seq, "demotion[C%zd] ",
1085                                    (pr->power.states[i].demotion.state -
1086                                     pr->power.states));
1087                 else
1088                         seq_puts(seq, "demotion[--] ");
1089
1090                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1091                            pr->power.states[i].latency,
1092                            pr->power.states[i].usage,
1093                            (unsigned long long)pr->power.states[i].time);
1094         }
1095
1096       end:
1097         return 0;
1098 }
1099
1100 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1101 {
1102         return single_open(file, acpi_processor_power_seq_show,
1103                            PDE(inode)->data);
1104 }
1105
1106 static const struct file_operations acpi_processor_power_fops = {
1107         .open = acpi_processor_power_open_fs,
1108         .read = seq_read,
1109         .llseek = seq_lseek,
1110         .release = single_release,
1111 };
1112
1113 #ifdef CONFIG_SMP
1114 static void smp_callback(void *v)
1115 {
1116         /* we already woke the CPU up, nothing more to do */
1117 }
1118
1119 /*
1120  * This function gets called when a part of the kernel has a new latency
1121  * requirement.  This means we need to get all processors out of their C-state,
1122  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1123  * wakes them all right up.
1124  */
1125 static int acpi_processor_latency_notify(struct notifier_block *b,
1126                 unsigned long l, void *v)
1127 {
1128         smp_call_function(smp_callback, NULL, 0, 1);
1129         return NOTIFY_OK;
1130 }
1131
1132 static struct notifier_block acpi_processor_latency_notifier = {
1133         .notifier_call = acpi_processor_latency_notify,
1134 };
1135 #endif
1136
1137 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1138                               struct acpi_device *device)
1139 {
1140         acpi_status status = 0;
1141         static int first_run;
1142         struct proc_dir_entry *entry = NULL;
1143         unsigned int i;
1144
1145
1146         if (!first_run) {
1147                 dmi_check_system(processor_power_dmi_table);
1148                 if (max_cstate < ACPI_C_STATES_MAX)
1149                         printk(KERN_NOTICE
1150                                "ACPI: processor limited to max C-state %d\n",
1151                                max_cstate);
1152                 first_run++;
1153 #ifdef CONFIG_SMP
1154                 register_latency_notifier(&acpi_processor_latency_notifier);
1155 #endif
1156         }
1157
1158         if (!pr)
1159                 return -EINVAL;
1160
1161         if (acpi_gbl_FADT.cst_control && !nocst) {
1162                 status =
1163                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1164                 if (ACPI_FAILURE(status)) {
1165                         ACPI_EXCEPTION((AE_INFO, status,
1166                                         "Notifying BIOS of _CST ability failed"));
1167                 }
1168         }
1169
1170         acpi_processor_get_power_info(pr);
1171
1172         /*
1173          * Install the idle handler if processor power management is supported.
1174          * Note that we use previously set idle handler will be used on
1175          * platforms that only support C1.
1176          */
1177         if ((pr->flags.power) && (!boot_option_idle_override)) {
1178                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1179                 for (i = 1; i <= pr->power.count; i++)
1180                         if (pr->power.states[i].valid)
1181                                 printk(" C%d[C%d]", i,
1182                                        pr->power.states[i].type);
1183                 printk(")\n");
1184
1185                 if (pr->id == 0) {
1186                         pm_idle_save = pm_idle;
1187                         pm_idle = acpi_processor_idle;
1188                 }
1189         }
1190
1191         /* 'power' [R] */
1192         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1193                                   S_IRUGO, acpi_device_dir(device));
1194         if (!entry)
1195                 return -EIO;
1196         else {
1197                 entry->proc_fops = &acpi_processor_power_fops;
1198                 entry->data = acpi_driver_data(device);
1199                 entry->owner = THIS_MODULE;
1200         }
1201
1202         pr->flags.power_setup_done = 1;
1203
1204         return 0;
1205 }
1206
1207 int acpi_processor_power_exit(struct acpi_processor *pr,
1208                               struct acpi_device *device)
1209 {
1210
1211         pr->flags.power_setup_done = 0;
1212
1213         if (acpi_device_dir(device))
1214                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1215                                   acpi_device_dir(device));
1216
1217         /* Unregister the idle handler when processor #0 is removed. */
1218         if (pr->id == 0) {
1219                 pm_idle = pm_idle_save;
1220
1221                 /*
1222                  * We are about to unload the current idle thread pm callback
1223                  * (pm_idle), Wait for all processors to update cached/local
1224                  * copies of pm_idle before proceeding.
1225                  */
1226                 cpu_idle_wait();
1227 #ifdef CONFIG_SMP
1228                 unregister_latency_notifier(&acpi_processor_latency_notifier);
1229 #endif
1230         }
1231
1232         return 0;
1233 }