drivers/acpi/processor_idle.c

   1 /*
   2  * processor_idle - idle state submodule to the ACPI processor driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *                      - Added support for C3 on SMP
  11  *
  12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or (at
  17  *  your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful, but
  20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  *  General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License along
  25  *  with this program; if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  27  *
  28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/cpufreq.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/sched.h>        /* need_resched() */
  41 #include <linux/latency.h>
  42 #include <linux/clockchips.h>
  43 #include <linux/cpuidle.h>
  44
  45 /*
  46  * Include the apic definitions for x86 to have the APIC timer related defines
  47  * available also for UP (on SMP it gets magically included via linux/smp.h).
  48  * asm/acpi.h is not an option, as it would require more include magic. Also
  49  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  50  */
  51 #ifdef CONFIG_X86
  52 #include <asm/apic.h>
  53 #endif
  54
  55 #include <asm/io.h>
  56 #include <asm/uaccess.h>
  57
  58 #include <acpi/acpi_bus.h>
  59 #include <acpi/processor.h>
  60
  61 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  62 #define ACPI_PROCESSOR_CLASS            "processor"
  63 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  64 ACPI_MODULE_NAME("processor_idle");
  65 #define ACPI_PROCESSOR_FILE_POWER       "power"
  66 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  67 #define PM_TIMER_TICK_NS                (1000000000ULL/PM_TIMER_FREQUENCY)
  68 #ifndef CONFIG_CPU_IDLE
  69 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  70 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  71 static void (*pm_idle_save) (void) __read_mostly;
  72 #else
  73 #define C2_OVERHEAD                     1       /* 1us */
  74 #define C3_OVERHEAD                     1       /* 1us */
  75 #endif
  76 #define PM_TIMER_TICKS_TO_US(p)         (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
  77
  78 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  79 module_param(max_cstate, uint, 0000);
  80 static unsigned int nocst __read_mostly;
  81 module_param(nocst, uint, 0000);
  82
  83 #ifndef CONFIG_CPU_IDLE
  84 /*
  85  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  86  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  87  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  88  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  89  * reduce history for more aggressive entry into C3
  90  */
  91 static unsigned int bm_history __read_mostly =
  92     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  93 module_param(bm_history, uint, 0644);
  94
  95 static int acpi_processor_set_power_policy(struct acpi_processor *pr);
  96
  97 #endif
  98
  99 /*
 100  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
 101  * For now disable this. Probably a bug somewhere else.
 102  *
 103  * To skip this limit, boot/load with a large max_cstate limit.
 104  */
 105 static int set_max_cstate(const struct dmi_system_id *id)
 106 {
 107         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
 108                 return 0;
 109
 110         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
 111                " Override with \"processor.max_cstate=%d\"\n", id->ident,
 112                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
 113
 114         max_cstate = (long)id->driver_data;
 115
 116         return 0;
 117 }
 118
 119 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
 120    callers to only run once -AK */
 121 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 122         { set_max_cstate, "IBM ThinkPad R40e", {
 123           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 124           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 125         { set_max_cstate, "IBM ThinkPad R40e", {
 126           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 127           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 128         { set_max_cstate, "IBM ThinkPad R40e", {
 129           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 130           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 131         { set_max_cstate, "IBM ThinkPad R40e", {
 132           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 133           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 134         { set_max_cstate, "IBM ThinkPad R40e", {
 135           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 136           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 137         { set_max_cstate, "IBM ThinkPad R40e", {
 138           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 139           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 140         { set_max_cstate, "IBM ThinkPad R40e", {
 141           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 142           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 143         { set_max_cstate, "IBM ThinkPad R40e", {
 144           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 145           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 146         { set_max_cstate, "IBM ThinkPad R40e", {
 147           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 148           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 149         { set_max_cstate, "IBM ThinkPad R40e", {
 150           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 151           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 152         { set_max_cstate, "IBM ThinkPad R40e", {
 153           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 154           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 155         { set_max_cstate, "IBM ThinkPad R40e", {
 156           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 157           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 158         { set_max_cstate, "IBM ThinkPad R40e", {
 159           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 160           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 161         { set_max_cstate, "IBM ThinkPad R40e", {
 162           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 163           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 164         { set_max_cstate, "IBM ThinkPad R40e", {
 165           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 166           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 167         { set_max_cstate, "IBM ThinkPad R40e", {
 168           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 169           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 170         { set_max_cstate, "Medion 41700", {
 171           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 172           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 173         { set_max_cstate, "Clevo 5600D", {
 174           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 175           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 176          (void *)2},
 177         {},
 178 };
 179
 180 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 181 {
 182         if (t2 >= t1)
 183                 return (t2 - t1);
 184         else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 185                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 186         else
 187                 return ((0xFFFFFFFF - t1) + t2);
 188 }
 189
 190 static inline u32 ticks_elapsed_in_us(u32 t1, u32 t2)
 191 {
 192         if (t2 >= t1)
 193                 return PM_TIMER_TICKS_TO_US(t2 - t1);
 194         else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 195                 return PM_TIMER_TICKS_TO_US(((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 196         else
 197                 return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
 198 }
 199
 200 static void acpi_safe_halt(void)
 201 {
 202         current_thread_info()->status &= ~TS_POLLING;
 203         /*
 204          * TS_POLLING-cleared state must be visible before we
 205          * test NEED_RESCHED:
 206          */
 207         smp_mb();
 208         if (!need_resched())
 209                 safe_halt();
 210         current_thread_info()->status |= TS_POLLING;
 211 }
 212
 213 #ifndef CONFIG_CPU_IDLE
 214
 215 static void
 216 acpi_processor_power_activate(struct acpi_processor *pr,
 217                               struct acpi_processor_cx *new)
 218 {
 219         struct acpi_processor_cx *old;
 220
 221         if (!pr || !new)
 222                 return;
 223
 224         old = pr->power.state;
 225
 226         if (old)
 227                 old->promotion.count = 0;
 228         new->demotion.count = 0;
 229
 230         /* Cleanup from old state. */
 231         if (old) {
 232                 switch (old->type) {
 233                 case ACPI_STATE_C3:
 234                         /* Disable bus master reload */
 235                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 236                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 237                         break;
 238                 }
 239         }
 240
 241         /* Prepare to use new state. */
 242         switch (new->type) {
 243         case ACPI_STATE_C3:
 244                 /* Enable bus master reload */
 245                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 246                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 247                 break;
 248         }
 249
 250         pr->power.state = new;
 251
 252         return;
 253 }
 254
 255 static atomic_t c3_cpu_count;
 256
 257 /* Common C-state entry for C2, C3, .. */
 258 static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
 259 {
 260         if (cstate->space_id == ACPI_CSTATE_FFH) {
 261                 /* Call into architectural FFH based C-state */
 262                 acpi_processor_ffh_cstate_enter(cstate);
 263         } else {
 264                 int unused;
 265                 /* IO port based C-state */
 266                 inb(cstate->address);
 267                 /* Dummy wait op - must do something useless after P_LVL2 read
 268                    because chipsets cannot guarantee that STPCLK# signal
 269                    gets asserted in time to freeze execution properly. */
 270                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
 271         }
 272 }
 273 #endif /* !CONFIG_CPU_IDLE */
 274
 275 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 276
 277 /*
 278  * Some BIOS implementations switch to C3 in the published C2 state.
 279  * This seems to be a common problem on AMD boxen, but other vendors
 280  * are affected too. We pick the most conservative approach: we assume
 281  * that the local APIC stops in both C2 and C3.
 282  */
 283 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 284                                    struct acpi_processor_cx *cx)
 285 {
 286         struct acpi_processor_power *pwr = &pr->power;
 287         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 288
 289         /*
 290          * Check, if one of the previous states already marked the lapic
 291          * unstable
 292          */
 293         if (pwr->timer_broadcast_on_state < state)
 294                 return;
 295
 296         if (cx->type >= type)
 297                 pr->power.timer_broadcast_on_state = state;
 298 }
 299
 300 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)
 301 {
 302         unsigned long reason;
 303
 304         reason = pr->power.timer_broadcast_on_state < INT_MAX ?
 305                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
 306
 307         clockevents_notify(reason, &pr->id);
 308 }
 309
 310 /* Power(C) State timer broadcast control */
 311 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 312                                        struct acpi_processor_cx *cx,
 313                                        int broadcast)
 314 {
 315         int state = cx - pr->power.states;
 316
 317         if (state >= pr->power.timer_broadcast_on_state) {
 318                 unsigned long reason;
 319
 320                 reason = broadcast ?  CLOCK_EVT_NOTIFY_BROADCAST_ENTER :
 321                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT;
 322                 clockevents_notify(reason, &pr->id);
 323         }
 324 }
 325
 326 #else
 327
 328 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 329                                    struct acpi_processor_cx *cstate) { }
 330 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { }
 331 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 332                                        struct acpi_processor_cx *cx,
 333                                        int broadcast)
 334 {
 335 }
 336
 337 #endif
 338
 339 /*
 340  * Suspend / resume control
 341  */
 342 static int acpi_idle_suspend;
 343
 344 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
 345 {
 346         acpi_idle_suspend = 1;
 347         return 0;
 348 }
 349
 350 int acpi_processor_resume(struct acpi_device * device)
 351 {
 352         acpi_idle_suspend = 0;
 353         return 0;
 354 }
 355
 356 #ifndef CONFIG_CPU_IDLE
 357 static void acpi_processor_idle(void)
 358 {
 359         struct acpi_processor *pr = NULL;
 360         struct acpi_processor_cx *cx = NULL;
 361         struct acpi_processor_cx *next_state = NULL;
 362         int sleep_ticks = 0;
 363         u32 t1, t2 = 0;
 364
 365         /*
 366          * Interrupts must be disabled during bus mastering calculations and
 367          * for C2/C3 transitions.
 368          */
 369         local_irq_disable();
 370
 371         pr = processors[smp_processor_id()];
 372         if (!pr) {
 373                 local_irq_enable();
 374                 return;
 375         }
 376
 377         /*
 378          * Check whether we truly need to go idle, or should
 379          * reschedule:
 380          */
 381         if (unlikely(need_resched())) {
 382                 local_irq_enable();
 383                 return;
 384         }
 385
 386         cx = pr->power.state;
 387         if (!cx || acpi_idle_suspend) {
 388                 if (pm_idle_save)
 389                         pm_idle_save();
 390                 else
 391                         acpi_safe_halt();
 392                 return;
 393         }
 394
 395         /*
 396          * Check BM Activity
 397          * -----------------
 398          * Check for bus mastering activity (if required), record, and check
 399          * for demotion.
 400          */
 401         if (pr->flags.bm_check) {
 402                 u32 bm_status = 0;
 403                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 404
 405                 if (diff > 31)
 406                         diff = 31;
 407
 408                 pr->power.bm_activity <<= diff;
 409
 410                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 411                 if (bm_status) {
 412                         pr->power.bm_activity |= 0x1;
 413                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 414                 }
 415                 /*
 416                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 417                  * the true state of bus mastering activity; forcing us to
 418                  * manually check the BMIDEA bit of each IDE channel.
 419                  */
 420                 else if (errata.piix4.bmisx) {
 421                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 422                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 423                                 pr->power.bm_activity |= 0x1;
 424                 }
 425
 426                 pr->power.bm_check_timestamp = jiffies;
 427
 428                 /*
 429                  * If bus mastering is or was active this jiffy, demote
 430                  * to avoid a faulty transition.  Note that the processor
 431                  * won't enter a low-power state during this call (to this
 432                  * function) but should upon the next.
 433                  *
 434                  * TBD: A better policy might be to fallback to the demotion
 435                  *      state (use it for this quantum only) istead of
 436                  *      demoting -- and rely on duration as our sole demotion
 437                  *      qualification.  This may, however, introduce DMA
 438                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 439                  */
 440                 if ((pr->power.bm_activity & 0x1) &&
 441                     cx->demotion.threshold.bm) {
 442                         local_irq_enable();
 443                         next_state = cx->demotion.state;
 444                         goto end;
 445                 }
 446         }
 447
 448 #ifdef CONFIG_HOTPLUG_CPU
 449         /*
 450          * Check for P_LVL2_UP flag before entering C2 and above on
 451          * an SMP system. We do it here instead of doing it at _CST/P_LVL
 452          * detection phase, to work cleanly with logical CPU hotplug.
 453          */
 454         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 455             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 456                 cx = &pr->power.states[ACPI_STATE_C1];
 457 #endif
 458
 459         /*
 460          * Sleep:
 461          * ------
 462          * Invoke the current Cx state to put the processor to sleep.
 463          */
 464         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 465                 current_thread_info()->status &= ~TS_POLLING;
 466                 /*
 467                  * TS_POLLING-cleared state must be visible before we
 468                  * test NEED_RESCHED:
 469                  */
 470                 smp_mb();
 471                 if (need_resched()) {
 472                         current_thread_info()->status |= TS_POLLING;
 473                         local_irq_enable();
 474                         return;
 475                 }
 476         }
 477
 478         switch (cx->type) {
 479
 480         case ACPI_STATE_C1:
 481                 /*
 482                  * Invoke C1.
 483                  * Use the appropriate idle routine, the one that would
 484                  * be used without acpi C-states.
 485                  */
 486                 if (pm_idle_save)
 487                         pm_idle_save();
 488                 else
 489                         acpi_safe_halt();
 490
 491                 /*
 492                  * TBD: Can't get time duration while in C1, as resumes
 493                  *      go to an ISR rather than here.  Need to instrument
 494                  *      base interrupt handler.
 495                  *
 496                  * Note: the TSC better not stop in C1, sched_clock() will
 497                  *       skew otherwise.
 498                  */
 499                 sleep_ticks = 0xFFFFFFFF;
 500                 break;
 501
 502         case ACPI_STATE_C2:
 503                 /* Get start time (ticks) */
 504                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 505                 /* Tell the scheduler that we are going deep-idle: */
 506                 sched_clock_idle_sleep_event();
 507                 /* Invoke C2 */
 508                 acpi_state_timer_broadcast(pr, cx, 1);
 509                 acpi_cstate_enter(cx);
 510                 /* Get end time (ticks) */
 511                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 512
 513 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
 514                 /* TSC halts in C2, so notify users */
 515                 mark_tsc_unstable("possible TSC halt in C2");
 516 #endif
 517                 /* Compute time (ticks) that we were actually asleep */
 518                 sleep_ticks = ticks_elapsed(t1, t2);
 519
 520                 /* Tell the scheduler how much we idled: */
 521                 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
 522
 523                 /* Re-enable interrupts */
 524                 local_irq_enable();
 525                 /* Do not account our idle-switching overhead: */
 526                 sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
 527
 528                 current_thread_info()->status |= TS_POLLING;
 529                 acpi_state_timer_broadcast(pr, cx, 0);
 530                 break;
 531
 532         case ACPI_STATE_C3:
 533                 /*
 534                  * Must be done before busmaster disable as we might
 535                  * need to access HPET !
 536                  */
 537                 acpi_state_timer_broadcast(pr, cx, 1);
 538                 /*
 539                  * disable bus master
 540                  * bm_check implies we need ARB_DIS
 541                  * !bm_check implies we need cache flush
 542                  * bm_control implies whether we can do ARB_DIS
 543                  *
 544                  * That leaves a case where bm_check is set and bm_control is
 545                  * not set. In that case we cannot do much, we enter C3
 546                  * without doing anything.
 547                  */
 548                 if (pr->flags.bm_check && pr->flags.bm_control) {
 549                         if (atomic_inc_return(&c3_cpu_count) ==
 550                             num_online_cpus()) {
 551                                 /*
 552                                  * All CPUs are trying to go to C3
 553                                  * Disable bus master arbitration
 554                                  */
 555                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
 556                         }
 557                 } else if (!pr->flags.bm_check) {
 558                         /* SMP with no shared cache... Invalidate cache  */
 559                         ACPI_FLUSH_CPU_CACHE();
 560                 }
 561
 562                 /* Get start time (ticks) */
 563                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 564                 /* Invoke C3 */
 565                 /* Tell the scheduler that we are going deep-idle: */
 566                 sched_clock_idle_sleep_event();
 567                 acpi_cstate_enter(cx);
 568                 /* Get end time (ticks) */
 569                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 570                 if (pr->flags.bm_check && pr->flags.bm_control) {
 571                         /* Enable bus master arbitration */
 572                         atomic_dec(&c3_cpu_count);
 573                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
 574                 }
 575
 576 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
 577                 /* TSC halts in C3, so notify users */
 578                 mark_tsc_unstable("TSC halts in C3");
 579 #endif
 580                 /* Compute time (ticks) that we were actually asleep */
 581                 sleep_ticks = ticks_elapsed(t1, t2);
 582                 /* Tell the scheduler how much we idled: */
 583                 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
 584
 585                 /* Re-enable interrupts */
 586                 local_irq_enable();
 587                 /* Do not account our idle-switching overhead: */
 588                 sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
 589
 590                 current_thread_info()->status |= TS_POLLING;
 591                 acpi_state_timer_broadcast(pr, cx, 0);
 592                 break;
 593
 594         default:
 595                 local_irq_enable();
 596                 return;
 597         }
 598         cx->usage++;
 599         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 600                 cx->time += sleep_ticks;
 601
 602         next_state = pr->power.state;
 603
 604 #ifdef CONFIG_HOTPLUG_CPU
 605         /* Don't do promotion/demotion */
 606         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 607             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
 608                 next_state = cx;
 609                 goto end;
 610         }
 611 #endif
 612
 613         /*
 614          * Promotion?
 615          * ----------
 616          * Track the number of longs (time asleep is greater than threshold)
 617          * and promote when the count threshold is reached.  Note that bus
 618          * mastering activity may prevent promotions.
 619          * Do not promote above max_cstate.
 620          */
 621         if (cx->promotion.state &&
 622             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 623                 if (sleep_ticks > cx->promotion.threshold.ticks &&
 624                   cx->promotion.state->latency <= system_latency_constraint()) {
 625                         cx->promotion.count++;
 626                         cx->demotion.count = 0;
 627                         if (cx->promotion.count >=
 628                             cx->promotion.threshold.count) {
 629                                 if (pr->flags.bm_check) {
 630                                         if (!
 631                                             (pr->power.bm_activity & cx->
 632                                              promotion.threshold.bm)) {
 633                                                 next_state =
 634                                                     cx->promotion.state;
 635                                                 goto end;
 636                                         }
 637                                 } else {
 638                                         next_state = cx->promotion.state;
 639                                         goto end;
 640                                 }
 641                         }
 642                 }
 643         }
 644
 645         /*
 646          * Demotion?
 647          * ---------
 648          * Track the number of shorts (time asleep is less than time threshold)
 649          * and demote when the usage threshold is reached.
 650          */
 651         if (cx->demotion.state) {
 652                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 653                         cx->demotion.count++;
 654                         cx->promotion.count = 0;
 655                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 656                                 next_state = cx->demotion.state;
 657                                 goto end;
 658                         }
 659                 }
 660         }
 661
 662       end:
 663         /*
 664          * Demote if current state exceeds max_cstate
 665          * or if the latency of the current state is unacceptable
 666          */
 667         if ((pr->power.state - pr->power.states) > max_cstate ||
 668                 pr->power.state->latency > system_latency_constraint()) {
 669                 if (cx->demotion.state)
 670                         next_state = cx->demotion.state;
 671         }
 672
 673         /*
 674          * New Cx State?
 675          * -------------
 676          * If we're going to start using a new Cx state we must clean up
 677          * from the previous and prepare to use the new.
 678          */
 679         if (next_state != pr->power.state)
 680                 acpi_processor_power_activate(pr, next_state);
 681 }
 682
 683 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 684 {
 685         unsigned int i;
 686         unsigned int state_is_set = 0;
 687         struct acpi_processor_cx *lower = NULL;
 688         struct acpi_processor_cx *higher = NULL;
 689         struct acpi_processor_cx *cx;
 690
 691
 692         if (!pr)
 693                 return -EINVAL;
 694
 695         /*
 696          * This function sets the default Cx state policy (OS idle handler).
 697          * Our scheme is to promote quickly to C2 but more conservatively
 698          * to C3.  We're favoring C2  for its characteristics of low latency
 699          * (quick response), good power savings, and ability to allow bus
 700          * mastering activity.  Note that the Cx state policy is completely
 701          * customizable and can be altered dynamically.
 702          */
 703
 704         /* startup state */
 705         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 706                 cx = &pr->power.states[i];
 707                 if (!cx->valid)
 708                         continue;
 709
 710                 if (!state_is_set)
 711                         pr->power.state = cx;
 712                 state_is_set++;
 713                 break;
 714         }
 715
 716         if (!state_is_set)
 717                 return -ENODEV;
 718
 719         /* demotion */
 720         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 721                 cx = &pr->power.states[i];
 722                 if (!cx->valid)
 723                         continue;
 724
 725                 if (lower) {
 726                         cx->demotion.state = lower;
 727                         cx->demotion.threshold.ticks = cx->latency_ticks;
 728                         cx->demotion.threshold.count = 1;
 729                         if (cx->type == ACPI_STATE_C3)
 730                                 cx->demotion.threshold.bm = bm_history;
 731                 }
 732
 733                 lower = cx;
 734         }
 735
 736         /* promotion */
 737         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 738                 cx = &pr->power.states[i];
 739                 if (!cx->valid)
 740                         continue;
 741
 742                 if (higher) {
 743                         cx->promotion.state = higher;
 744                         cx->promotion.threshold.ticks = cx->latency_ticks;
 745                         if (cx->type >= ACPI_STATE_C2)
 746                                 cx->promotion.threshold.count = 4;
 747                         else
 748                                 cx->promotion.threshold.count = 10;
 749                         if (higher->type == ACPI_STATE_C3)
 750                                 cx->promotion.threshold.bm = bm_history;
 751                 }
 752
 753                 higher = cx;
 754         }
 755
 756         return 0;
 757 }
 758 #endif /* !CONFIG_CPU_IDLE */
 759
 760 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 761 {
 762
 763         if (!pr)
 764                 return -EINVAL;
 765
 766         if (!pr->pblk)
 767                 return -ENODEV;
 768
 769         /* if info is obtained from pblk/fadt, type equals state */
 770         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 771         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 772
 773 #ifndef CONFIG_HOTPLUG_CPU
 774         /*
 775          * Check for P_LVL2_UP flag before entering C2 and above on
 776          * an SMP system.
 777          */
 778         if ((num_online_cpus() > 1) &&
 779             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 780                 return -ENODEV;
 781 #endif
 782
 783         /* determine C2 and C3 address from pblk */
 784         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 785         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 786
 787         /* determine latencies from FADT */
 788         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency;
 789         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency;
 790
 791         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 792                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 793                           pr->power.states[ACPI_STATE_C2].address,
 794                           pr->power.states[ACPI_STATE_C3].address));
 795
 796         return 0;
 797 }
 798
 799 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 800 {
 801         if (!pr->power.states[ACPI_STATE_C1].valid) {
 802                 /* set the first C-State to C1 */
 803                 /* all processors need to support C1 */
 804                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 805                 pr->power.states[ACPI_STATE_C1].valid = 1;
 806         }
 807         /* the C0 state only exists as a filler in our array */
 808         pr->power.states[ACPI_STATE_C0].valid = 1;
 809         return 0;
 810 }
 811
 812 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 813 {
 814         acpi_status status = 0;
 815         acpi_integer count;
 816         int current_count;
 817         int i;
 818         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 819         union acpi_object *cst;
 820
 821
 822         if (nocst)
 823                 return -ENODEV;
 824
 825         current_count = 0;
 826
 827         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 828         if (ACPI_FAILURE(status)) {
 829                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 830                 return -ENODEV;
 831         }
 832
 833         cst = buffer.pointer;
 834
 835         /* There must be at least 2 elements */
 836         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 837                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 838                 status = -EFAULT;
 839                 goto end;
 840         }
 841
 842         count = cst->package.elements[0].integer.value;
 843
 844         /* Validate number of power states. */
 845         if (count < 1 || count != cst->package.count - 1) {
 846                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 847                 status = -EFAULT;
 848                 goto end;
 849         }
 850
 851         /* Tell driver that at least _CST is supported. */
 852         pr->flags.has_cst = 1;
 853
 854         for (i = 1; i <= count; i++) {
 855                 union acpi_object *element;
 856                 union acpi_object *obj;
 857                 struct acpi_power_register *reg;
 858                 struct acpi_processor_cx cx;
 859
 860                 memset(&cx, 0, sizeof(cx));
 861
 862                 element = &(cst->package.elements[i]);
 863                 if (element->type != ACPI_TYPE_PACKAGE)
 864                         continue;
 865
 866                 if (element->package.count != 4)
 867                         continue;
 868
 869                 obj = &(element->package.elements[0]);
 870
 871                 if (obj->type != ACPI_TYPE_BUFFER)
 872                         continue;
 873
 874                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 875
 876                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 877                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 878                         continue;
 879
 880                 /* There should be an easy way to extract an integer... */
 881                 obj = &(element->package.elements[1]);
 882                 if (obj->type != ACPI_TYPE_INTEGER)
 883                         continue;
 884
 885                 cx.type = obj->integer.value;
 886                 /*
 887                  * Some buggy BIOSes won't list C1 in _CST -
 888                  * Let acpi_processor_get_power_info_default() handle them later
 889                  */
 890                 if (i == 1 && cx.type != ACPI_STATE_C1)
 891                         current_count++;
 892
 893                 cx.address = reg->address;
 894                 cx.index = current_count + 1;
 895
 896                 cx.space_id = ACPI_CSTATE_SYSTEMIO;
 897                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 898                         if (acpi_processor_ffh_cstate_probe
 899                                         (pr->id, &cx, reg) == 0) {
 900                                 cx.space_id = ACPI_CSTATE_FFH;
 901                         } else if (cx.type != ACPI_STATE_C1) {
 902                                 /*
 903                                  * C1 is a special case where FIXED_HARDWARE
 904                                  * can be handled in non-MWAIT way as well.
 905                                  * In that case, save this _CST entry info.
 906                                  * That is, we retain space_id of SYSTEM_IO for
 907                                  * halt based C1.
 908                                  * Otherwise, ignore this info and continue.
 909                                  */
 910                                 continue;
 911                         }
 912                 }
 913
 914                 obj = &(element->package.elements[2]);
 915                 if (obj->type != ACPI_TYPE_INTEGER)
 916                         continue;
 917
 918                 cx.latency = obj->integer.value;
 919
 920                 obj = &(element->package.elements[3]);
 921                 if (obj->type != ACPI_TYPE_INTEGER)
 922                         continue;
 923
 924                 cx.power = obj->integer.value;
 925
 926                 current_count++;
 927                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 928
 929                 /*
 930                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 931                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 932                  */
 933                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 934                         printk(KERN_WARNING
 935                                "Limiting number of power states to max (%d)\n",
 936                                ACPI_PROCESSOR_MAX_POWER);
 937                         printk(KERN_WARNING
 938                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 939                         break;
 940                 }
 941         }
 942
 943         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 944                           current_count));
 945
 946         /* Validate number of power states discovered */
 947         if (current_count < 2)
 948                 status = -EFAULT;
 949
 950       end:
 951         kfree(buffer.pointer);
 952
 953         return status;
 954 }
 955
 956 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 957 {
 958
 959         if (!cx->address)
 960                 return;
 961
 962         /*
 963          * C2 latency must be less than or equal to 100
 964          * microseconds.
 965          */
 966         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 967                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 968                                   "latency too large [%d]\n", cx->latency));
 969                 return;
 970         }
 971
 972         /*
 973          * Otherwise we've met all of our C2 requirements.
 974          * Normalize the C2 latency to expidite policy
 975          */
 976         cx->valid = 1;
 977
 978 #ifndef CONFIG_CPU_IDLE
 979         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
 980 #else
 981         cx->latency_ticks = cx->latency;
 982 #endif
 983
 984         return;
 985 }
 986
 987 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 988                                            struct acpi_processor_cx *cx)
 989 {
 990         static int bm_check_flag;
 991
 992
 993         if (!cx->address)
 994                 return;
 995
 996         /*
 997          * C3 latency must be less than or equal to 1000
 998          * microseconds.
 999          */
1000         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
1001                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1002                                   "latency too large [%d]\n", cx->latency));
1003                 return;
1004         }
1005
1006         /*
1007          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
1008          * DMA transfers are used by any ISA device to avoid livelock.
1009          * Note that we could disable Type-F DMA (as recommended by
1010          * the erratum), but this is known to disrupt certain ISA
1011          * devices thus we take the conservative approach.
1012          */
1013         else if (errata.piix4.fdma) {
1014                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1015                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
1016                 return;
1017         }
1018
1019         /* All the logic here assumes flags.bm_check is same across all CPUs */
1020         if (!bm_check_flag) {
1021                 /* Determine whether bm_check is needed based on CPU  */
1022                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
1023                 bm_check_flag = pr->flags.bm_check;
1024         } else {
1025                 pr->flags.bm_check = bm_check_flag;
1026         }
1027
1028         if (pr->flags.bm_check) {
1029                 if (!pr->flags.bm_control) {
1030                         if (pr->flags.has_cst != 1) {
1031                                 /* bus mastering control is necessary */
1032                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1033                                         "C3 support requires BM control\n"));
1034                                 return;
1035                         } else {
1036                                 /* Here we enter C3 without bus mastering */
1037                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1038                                         "C3 support without BM control\n"));
1039                         }
1040                 }
1041         } else {
1042                 /*
1043                  * WBINVD should be set in fadt, for C3 state to be
1044                  * supported on when bm_check is not required.
1045                  */
1046                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
1047                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1048                                           "Cache invalidation should work properly"
1049                                           " for C3 to be enabled on SMP systems\n"));
1050                         return;
1051                 }
1052                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
1053         }
1054
1055         /*
1056          * Otherwise we've met all of our C3 requirements.
1057          * Normalize the C3 latency to expidite policy.  Enable
1058          * checking of bus mastering status (bm_check) so we can
1059          * use this in our C3 policy
1060          */
1061         cx->valid = 1;
1062
1063 #ifndef CONFIG_CPU_IDLE
1064         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
1065 #else
1066         cx->latency_ticks = cx->latency;
1067 #endif
1068
1069         return;
1070 }
1071
1072 static int acpi_processor_power_verify(struct acpi_processor *pr)
1073 {
1074         unsigned int i;
1075         unsigned int working = 0;
1076
1077         pr->power.timer_broadcast_on_state = INT_MAX;
1078
1079         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1080                 struct acpi_processor_cx *cx = &pr->power.states[i];
1081
1082                 switch (cx->type) {
1083                 case ACPI_STATE_C1:
1084                         cx->valid = 1;
1085                         break;
1086
1087                 case ACPI_STATE_C2:
1088                         acpi_processor_power_verify_c2(cx);
1089                         if (cx->valid)
1090                                 acpi_timer_check_state(i, pr, cx);
1091                         break;
1092
1093                 case ACPI_STATE_C3:
1094                         acpi_processor_power_verify_c3(pr, cx);
1095                         if (cx->valid)
1096                                 acpi_timer_check_state(i, pr, cx);
1097                         break;
1098                 }
1099
1100                 if (cx->valid)
1101                         working++;
1102         }
1103
1104         acpi_propagate_timer_broadcast(pr);
1105
1106         return (working);
1107 }
1108
1109 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1110 {
1111         unsigned int i;
1112         int result;
1113
1114
1115         /* NOTE: the idle thread may not be running while calling
1116          * this function */
1117
1118         /* Zero initialize all the C-states info. */
1119         memset(pr->power.states, 0, sizeof(pr->power.states));
1120
1121         result = acpi_processor_get_power_info_cst(pr);
1122         if (result == -ENODEV)
1123                 result = acpi_processor_get_power_info_fadt(pr);
1124
1125         if (result)
1126                 return result;
1127
1128         acpi_processor_get_power_info_default(pr);
1129
1130         pr->power.count = acpi_processor_power_verify(pr);
1131
1132 #ifndef CONFIG_CPU_IDLE
1133         /*
1134          * Set Default Policy
1135          * ------------------
1136          * Now that we know which states are supported, set the default
1137          * policy.  Note that this policy can be changed dynamically
1138          * (e.g. encourage deeper sleeps to conserve battery life when
1139          * not on AC).
1140          */
1141         result = acpi_processor_set_power_policy(pr);
1142         if (result)
1143                 return result;
1144 #endif
1145
1146         /*
1147          * if one state of type C2 or C3 is available, mark this
1148          * CPU as being "idle manageable"
1149          */
1150         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1151                 if (pr->power.states[i].valid) {
1152                         pr->power.count = i;
1153                         if (pr->power.states[i].type >= ACPI_STATE_C2)
1154                                 pr->flags.power = 1;
1155                 }
1156         }
1157
1158         return 0;
1159 }
1160
1161 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1162 {
1163         struct acpi_processor *pr = seq->private;
1164         unsigned int i;
1165
1166
1167         if (!pr)
1168                 goto end;
1169
1170         seq_printf(seq, "active state:            C%zd\n"
1171                    "max_cstate:              C%d\n"
1172                    "bus master activity:     %08x\n"
1173                    "maximum allowed latency: %d usec\n",
1174                    pr->power.state ? pr->power.state - pr->power.states : 0,
1175                    max_cstate, (unsigned)pr->power.bm_activity,
1176                    system_latency_constraint());
1177
1178         seq_puts(seq, "states:\n");
1179
1180         for (i = 1; i <= pr->power.count; i++) {
1181                 seq_printf(seq, "   %cC%d:                  ",
1182                            (&pr->power.states[i] ==
1183                             pr->power.state ? '*' : ' '), i);
1184
1185                 if (!pr->power.states[i].valid) {
1186                         seq_puts(seq, "<not supported>\n");
1187                         continue;
1188                 }
1189
1190                 switch (pr->power.states[i].type) {
1191                 case ACPI_STATE_C1:
1192                         seq_printf(seq, "type[C1] ");
1193                         break;
1194                 case ACPI_STATE_C2:
1195                         seq_printf(seq, "type[C2] ");
1196                         break;
1197                 case ACPI_STATE_C3:
1198                         seq_printf(seq, "type[C3] ");
1199                         break;
1200                 default:
1201                         seq_printf(seq, "type[--] ");
1202                         break;
1203                 }
1204
1205                 if (pr->power.states[i].promotion.state)
1206                         seq_printf(seq, "promotion[C%zd] ",
1207                                    (pr->power.states[i].promotion.state -
1208                                     pr->power.states));
1209                 else
1210                         seq_puts(seq, "promotion[--] ");
1211
1212                 if (pr->power.states[i].demotion.state)
1213                         seq_printf(seq, "demotion[C%zd] ",
1214                                    (pr->power.states[i].demotion.state -
1215                                     pr->power.states));
1216                 else
1217                         seq_puts(seq, "demotion[--] ");
1218
1219                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1220                            pr->power.states[i].latency,
1221                            pr->power.states[i].usage,
1222                            (unsigned long long)pr->power.states[i].time);
1223         }
1224
1225       end:
1226         return 0;
1227 }
1228
1229 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1230 {
1231         return single_open(file, acpi_processor_power_seq_show,
1232                            PDE(inode)->data);
1233 }
1234
1235 static const struct file_operations acpi_processor_power_fops = {
1236         .open = acpi_processor_power_open_fs,
1237         .read = seq_read,
1238         .llseek = seq_lseek,
1239         .release = single_release,
1240 };
1241
1242 #ifndef CONFIG_CPU_IDLE
1243
1244 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1245 {
1246         int result = 0;
1247
1248
1249         if (!pr)
1250                 return -EINVAL;
1251
1252         if (nocst) {
1253                 return -ENODEV;
1254         }
1255
1256         if (!pr->flags.power_setup_done)
1257                 return -ENODEV;
1258
1259         /* Fall back to the default idle loop */
1260         pm_idle = pm_idle_save;
1261         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
1262
1263         pr->flags.power = 0;
1264         result = acpi_processor_get_power_info(pr);
1265         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1266                 pm_idle = acpi_processor_idle;
1267
1268         return result;
1269 }
1270
1271 #ifdef CONFIG_SMP
1272 static void smp_callback(void *v)
1273 {
1274         /* we already woke the CPU up, nothing more to do */
1275 }
1276
1277 /*
1278  * This function gets called when a part of the kernel has a new latency
1279  * requirement.  This means we need to get all processors out of their C-state,
1280  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1281  * wakes them all right up.
1282  */
1283 static int acpi_processor_latency_notify(struct notifier_block *b,
1284                 unsigned long l, void *v)
1285 {
1286         smp_call_function(smp_callback, NULL, 0, 1);
1287         return NOTIFY_OK;
1288 }
1289
1290 static struct notifier_block acpi_processor_latency_notifier = {
1291         .notifier_call = acpi_processor_latency_notify,
1292 };
1293
1294 #endif
1295
1296 #else /* CONFIG_CPU_IDLE */
1297
1298 /**
1299  * acpi_idle_bm_check - checks if bus master activity was detected
1300  */
1301 static int acpi_idle_bm_check(void)
1302 {
1303         u32 bm_status = 0;
1304
1305         acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
1306         if (bm_status)
1307                 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
1308         /*
1309          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
1310          * the true state of bus mastering activity; forcing us to
1311          * manually check the BMIDEA bit of each IDE channel.
1312          */
1313         else if (errata.piix4.bmisx) {
1314                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
1315                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
1316                         bm_status = 1;
1317         }
1318         return bm_status;
1319 }
1320
1321 /**
1322  * acpi_idle_update_bm_rld - updates the BM_RLD bit depending on target state
1323  * @pr: the processor
1324  * @target: the new target state
1325  */
1326 static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr,
1327                                            struct acpi_processor_cx *target)
1328 {
1329         if (pr->flags.bm_rld_set && target->type != ACPI_STATE_C3) {
1330                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
1331                 pr->flags.bm_rld_set = 0;
1332         }
1333
1334         if (!pr->flags.bm_rld_set && target->type == ACPI_STATE_C3) {
1335                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
1336                 pr->flags.bm_rld_set = 1;
1337         }
1338 }
1339
1340 /**
1341  * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
1342  * @cx: cstate data
1343  */
1344 static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
1345 {
1346         if (cx->space_id == ACPI_CSTATE_FFH) {
1347                 /* Call into architectural FFH based C-state */
1348                 acpi_processor_ffh_cstate_enter(cx);
1349         } else {
1350                 int unused;
1351                 /* IO port based C-state */
1352                 inb(cx->address);
1353                 /* Dummy wait op - must do something useless after P_LVL2 read
1354                    because chipsets cannot guarantee that STPCLK# signal
1355                    gets asserted in time to freeze execution properly. */
1356                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
1357         }
1358 }
1359
1360 /**
1361  * acpi_idle_enter_c1 - enters an ACPI C1 state-type
1362  * @dev: the target CPU
1363  * @state: the state data
1364  *
1365  * This is equivalent to the HALT instruction.
1366  */
1367 static int acpi_idle_enter_c1(struct cpuidle_device *dev,
1368                               struct cpuidle_state *state)
1369 {
1370         struct acpi_processor *pr;
1371         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1372         pr = processors[smp_processor_id()];
1373
1374         if (unlikely(!pr))
1375                 return 0;
1376
1377         if (pr->flags.bm_check)
1378                 acpi_idle_update_bm_rld(pr, cx);
1379
1380         acpi_safe_halt();
1381
1382         cx->usage++;
1383
1384         return 0;
1385 }
1386
1387 /**
1388  * acpi_idle_enter_simple - enters an ACPI state without BM handling
1389  * @dev: the target CPU
1390  * @state: the state data
1391  */
1392 static int acpi_idle_enter_simple(struct cpuidle_device *dev,
1393                                   struct cpuidle_state *state)
1394 {
1395         struct acpi_processor *pr;
1396         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1397         u32 t1, t2;
1398         int sleep_ticks = 0;
1399
1400         pr = processors[smp_processor_id()];
1401
1402         if (unlikely(!pr))
1403                 return 0;
1404
1405         if (acpi_idle_suspend)
1406                 return(acpi_idle_enter_c1(dev, state));
1407
1408         local_irq_disable();
1409         current_thread_info()->status &= ~TS_POLLING;
1410         /*
1411          * TS_POLLING-cleared state must be visible before we test
1412          * NEED_RESCHED:
1413          */
1414         smp_mb();
1415
1416         if (unlikely(need_resched())) {
1417                 current_thread_info()->status |= TS_POLLING;
1418                 local_irq_enable();
1419                 return 0;
1420         }
1421
1422         /*
1423          * Must be done before busmaster disable as we might need to
1424          * access HPET !
1425          */
1426         acpi_state_timer_broadcast(pr, cx, 1);
1427
1428         if (pr->flags.bm_check)
1429                 acpi_idle_update_bm_rld(pr, cx);
1430
1431         if (cx->type == ACPI_STATE_C3)
1432                 ACPI_FLUSH_CPU_CACHE();
1433
1434         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1435         /* Tell the scheduler that we are going deep-idle: */
1436         sched_clock_idle_sleep_event();
1437         acpi_idle_do_entry(cx);
1438         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1439
1440 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
1441         /* TSC could halt in idle, so notify users */
1442         mark_tsc_unstable("TSC halts in idle");;
1443 #endif
1444         sleep_ticks = ticks_elapsed(t1, t2);
1445
1446         /* Tell the scheduler how much we idled: */
1447         sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
1448
1449         local_irq_enable();
1450         current_thread_info()->status |= TS_POLLING;
1451
1452         cx->usage++;
1453
1454         acpi_state_timer_broadcast(pr, cx, 0);
1455         cx->time += sleep_ticks;
1456         return ticks_elapsed_in_us(t1, t2);
1457 }
1458
1459 static int c3_cpu_count;
1460 static DEFINE_SPINLOCK(c3_lock);
1461
1462 /**
1463  * acpi_idle_enter_bm - enters C3 with proper BM handling
1464  * @dev: the target CPU
1465  * @state: the state data
1466  *
1467  * If BM is detected, the deepest non-C3 idle state is entered instead.
1468  */
1469 static int acpi_idle_enter_bm(struct cpuidle_device *dev,
1470                               struct cpuidle_state *state)
1471 {
1472         struct acpi_processor *pr;
1473         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1474         u32 t1, t2;
1475         int sleep_ticks = 0;
1476
1477         pr = processors[smp_processor_id()];
1478
1479         if (unlikely(!pr))
1480                 return 0;
1481
1482         if (acpi_idle_suspend)
1483                 return(acpi_idle_enter_c1(dev, state));
1484
1485         if (acpi_idle_bm_check()) {
1486                 if (dev->safe_state) {
1487                         return dev->safe_state->enter(dev, dev->safe_state);
1488                 } else {
1489                         acpi_safe_halt();
1490                         return 0;
1491                 }
1492         }
1493
1494         local_irq_disable();
1495         current_thread_info()->status &= ~TS_POLLING;
1496         /*
1497          * TS_POLLING-cleared state must be visible before we test
1498          * NEED_RESCHED:
1499          */
1500         smp_mb();
1501
1502         if (unlikely(need_resched())) {
1503                 current_thread_info()->status |= TS_POLLING;
1504                 local_irq_enable();
1505                 return 0;
1506         }
1507
1508         /* Tell the scheduler that we are going deep-idle: */
1509         sched_clock_idle_sleep_event();
1510         /*
1511          * Must be done before busmaster disable as we might need to
1512          * access HPET !
1513          */
1514         acpi_state_timer_broadcast(pr, cx, 1);
1515
1516         acpi_idle_update_bm_rld(pr, cx);
1517
1518         /*
1519          * disable bus master
1520          * bm_check implies we need ARB_DIS
1521          * !bm_check implies we need cache flush
1522          * bm_control implies whether we can do ARB_DIS
1523          *
1524          * That leaves a case where bm_check is set and bm_control is
1525          * not set. In that case we cannot do much, we enter C3
1526          * without doing anything.
1527          */
1528         if (pr->flags.bm_check && pr->flags.bm_control) {
1529                 spin_lock(&c3_lock);
1530                 c3_cpu_count++;
1531                 /* Disable bus master arbitration when all CPUs are in C3 */
1532                 if (c3_cpu_count == num_online_cpus())
1533                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
1534                 spin_unlock(&c3_lock);
1535         } else if (!pr->flags.bm_check) {
1536                 ACPI_FLUSH_CPU_CACHE();
1537         }
1538
1539         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1540         acpi_idle_do_entry(cx);
1541         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1542
1543         /* Re-enable bus master arbitration */
1544         if (pr->flags.bm_check && pr->flags.bm_control) {
1545                 spin_lock(&c3_lock);
1546                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
1547                 c3_cpu_count--;
1548                 spin_unlock(&c3_lock);
1549         }
1550
1551 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
1552         /* TSC could halt in idle, so notify users */
1553         mark_tsc_unstable("TSC halts in idle");
1554 #endif
1555         sleep_ticks = ticks_elapsed(t1, t2);
1556         /* Tell the scheduler how much we idled: */
1557         sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
1558
1559         local_irq_enable();
1560         current_thread_info()->status |= TS_POLLING;
1561
1562         cx->usage++;
1563
1564         acpi_state_timer_broadcast(pr, cx, 0);
1565         cx->time += sleep_ticks;
1566         return ticks_elapsed_in_us(t1, t2);
1567 }
1568
1569 struct cpuidle_driver acpi_idle_driver = {
1570         .name =         "acpi_idle",
1571         .owner =        THIS_MODULE,
1572 };
1573
1574 /**
1575  * acpi_processor_setup_cpuidle - prepares and configures CPUIDLE
1576  * @pr: the ACPI processor
1577  */
1578 static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
1579 {
1580         int i, count = 0;
1581         struct acpi_processor_cx *cx;
1582         struct cpuidle_state *state;
1583         struct cpuidle_device *dev = &pr->power.dev;
1584
1585         if (!pr->flags.power_setup_done)
1586                 return -EINVAL;
1587
1588         if (pr->flags.power == 0) {
1589                 return -EINVAL;
1590         }
1591
1592         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
1593                 cx = &pr->power.states[i];
1594                 state = &dev->states[count];
1595
1596                 if (!cx->valid)
1597                         continue;
1598
1599 #ifdef CONFIG_HOTPLUG_CPU
1600                 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
1601                     !pr->flags.has_cst &&
1602                     !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
1603                         continue;
1604 #endif
1605                 cpuidle_set_statedata(state, cx);
1606
1607                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
1608                 state->exit_latency = cx->latency;
1609                 state->target_residency = cx->latency * 6;
1610                 state->power_usage = cx->power;
1611
1612                 state->flags = 0;
1613                 switch (cx->type) {
1614                         case ACPI_STATE_C1:
1615                         state->flags |= CPUIDLE_FLAG_SHALLOW;
1616                         state->enter = acpi_idle_enter_c1;
1617                         dev->safe_state = state;
1618                         break;
1619
1620                         case ACPI_STATE_C2:
1621                         state->flags |= CPUIDLE_FLAG_BALANCED;
1622                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1623                         state->enter = acpi_idle_enter_simple;
1624                         dev->safe_state = state;
1625                         break;
1626
1627                         case ACPI_STATE_C3:
1628                         state->flags |= CPUIDLE_FLAG_DEEP;
1629                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1630                         state->flags |= CPUIDLE_FLAG_CHECK_BM;
1631                         state->enter = pr->flags.bm_check ?
1632                                         acpi_idle_enter_bm :
1633                                         acpi_idle_enter_simple;
1634                         break;
1635                 }
1636
1637                 count++;
1638         }
1639
1640         dev->state_count = count;
1641
1642         if (!count)
1643                 return -EINVAL;
1644
1645         return 0;
1646 }
1647
1648 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1649 {
1650         int ret;
1651
1652         if (!pr)
1653                 return -EINVAL;
1654
1655         if (nocst) {
1656                 return -ENODEV;
1657         }
1658
1659         if (!pr->flags.power_setup_done)
1660                 return -ENODEV;
1661
1662         cpuidle_pause_and_lock();
1663         cpuidle_disable_device(&pr->power.dev);
1664         acpi_processor_get_power_info(pr);
1665         acpi_processor_setup_cpuidle(pr);
1666         ret = cpuidle_enable_device(&pr->power.dev);
1667         cpuidle_resume_and_unlock();
1668
1669         return ret;
1670 }
1671
1672 #endif /* CONFIG_CPU_IDLE */
1673
1674 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1675                               struct acpi_device *device)
1676 {
1677         acpi_status status = 0;
1678         static int first_run;
1679         struct proc_dir_entry *entry = NULL;
1680         unsigned int i;
1681
1682
1683         if (!first_run) {
1684                 dmi_check_system(processor_power_dmi_table);
1685                 max_cstate = acpi_processor_cstate_check(max_cstate);
1686                 if (max_cstate < ACPI_C_STATES_MAX)
1687                         printk(KERN_NOTICE
1688                                "ACPI: processor limited to max C-state %d\n",
1689                                max_cstate);
1690                 first_run++;
1691 #if !defined (CONFIG_CPU_IDLE) && defined (CONFIG_SMP)
1692                 register_latency_notifier(&acpi_processor_latency_notifier);
1693 #endif
1694         }
1695
1696         if (!pr)
1697                 return -EINVAL;
1698
1699         if (acpi_gbl_FADT.cst_control && !nocst) {
1700                 status =
1701                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1702                 if (ACPI_FAILURE(status)) {
1703                         ACPI_EXCEPTION((AE_INFO, status,
1704                                         "Notifying BIOS of _CST ability failed"));
1705                 }
1706         }
1707
1708         acpi_processor_get_power_info(pr);
1709         pr->flags.power_setup_done = 1;
1710
1711         /*
1712          * Install the idle handler if processor power management is supported.
1713          * Note that we use previously set idle handler will be used on
1714          * platforms that only support C1.
1715          */
1716         if ((pr->flags.power) && (!boot_option_idle_override)) {
1717 #ifdef CONFIG_CPU_IDLE
1718                 acpi_processor_setup_cpuidle(pr);
1719                 pr->power.dev.cpu = pr->id;
1720                 if (cpuidle_register_device(&pr->power.dev))
1721                         return -EIO;
1722 #endif
1723
1724                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1725                 for (i = 1; i <= pr->power.count; i++)
1726                         if (pr->power.states[i].valid)
1727                                 printk(" C%d[C%d]", i,
1728                                        pr->power.states[i].type);
1729                 printk(")\n");
1730
1731 #ifndef CONFIG_CPU_IDLE
1732                 if (pr->id == 0) {
1733                         pm_idle_save = pm_idle;
1734                         pm_idle = acpi_processor_idle;
1735                 }
1736 #endif
1737         }
1738
1739         /* 'power' [R] */
1740         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1741                                   S_IRUGO, acpi_device_dir(device));
1742         if (!entry)
1743                 return -EIO;
1744         else {
1745                 entry->proc_fops = &acpi_processor_power_fops;
1746                 entry->data = acpi_driver_data(device);
1747                 entry->owner = THIS_MODULE;
1748         }
1749
1750         return 0;
1751 }
1752
1753 int acpi_processor_power_exit(struct acpi_processor *pr,
1754                               struct acpi_device *device)
1755 {
1756 #ifdef CONFIG_CPU_IDLE
1757         if ((pr->flags.power) && (!boot_option_idle_override))
1758                 cpuidle_unregister_device(&pr->power.dev);
1759 #endif
1760         pr->flags.power_setup_done = 0;
1761
1762         if (acpi_device_dir(device))
1763                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1764                                   acpi_device_dir(device));
1765
1766 #ifndef CONFIG_CPU_IDLE
1767
1768         /* Unregister the idle handler when processor #0 is removed. */
1769         if (pr->id == 0) {
1770                 pm_idle = pm_idle_save;
1771
1772                 /*
1773                  * We are about to unload the current idle thread pm callback
1774                  * (pm_idle), Wait for all processors to update cached/local
1775                  * copies of pm_idle before proceeding.
1776                  */
1777                 cpu_idle_wait();
1778 #ifdef CONFIG_SMP
1779                 unregister_latency_notifier(&acpi_processor_latency_notifier);
1780 #endif
1781         }
1782 #endif
1783
1784         return 0;
1785 }