drivers/acpi/processor_idle.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * processor_idle - idle state submodule to the ACPI processor driver
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7  *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
   8  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   9  *                      - Added processor hotplug support
  10  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  11  *                      - Added support for C3 on SMP
  12  */
  13 #define pr_fmt(fmt) "ACPI: " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/acpi.h>
  17 #include <linux/dmi.h>
  18 #include <linux/sched.h>       /* need_resched() */
  19 #include <linux/sort.h>
  20 #include <linux/tick.h>
  21 #include <linux/cpuidle.h>
  22 #include <linux/cpu.h>
  23 #include <acpi/processor.h>
  24
  25 /*
  26  * Include the apic definitions for x86 to have the APIC timer related defines
  27  * available also for UP (on SMP it gets magically included via linux/smp.h).
  28  * asm/acpi.h is not an option, as it would require more include magic. Also
  29  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  30  */
  31 #ifdef CONFIG_X86
  32 #include <asm/apic.h>
  33 #include <asm/cpu.h>
  34 #endif
  35
  36 #define ACPI_IDLE_STATE_START   (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  37
  38 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  39 module_param(max_cstate, uint, 0000);
  40 static unsigned int nocst __read_mostly;
  41 module_param(nocst, uint, 0000);
  42 static int bm_check_disable __read_mostly;
  43 module_param(bm_check_disable, uint, 0000);
  44
  45 static unsigned int latency_factor __read_mostly = 2;
  46 module_param(latency_factor, uint, 0644);
  47
  48 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  49
  50 struct cpuidle_driver acpi_idle_driver = {
  51         .name =         "acpi_idle",
  52         .owner =        THIS_MODULE,
  53 };
  54
  55 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  56 static
  57 DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  58
  59 static int disabled_by_idle_boot_param(void)
  60 {
  61         return boot_option_idle_override == IDLE_POLL ||
  62                 boot_option_idle_override == IDLE_HALT;
  63 }
  64
  65 /*
  66  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  67  * For now disable this. Probably a bug somewhere else.
  68  *
  69  * To skip this limit, boot/load with a large max_cstate limit.
  70  */
  71 static int set_max_cstate(const struct dmi_system_id *id)
  72 {
  73         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  74                 return 0;
  75
  76         pr_notice("%s detected - limiting to C%ld max_cstate."
  77                   " Override with \"processor.max_cstate=%d\"\n", id->ident,
  78                   (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  79
  80         max_cstate = (long)id->driver_data;
  81
  82         return 0;
  83 }
  84
  85 static const struct dmi_system_id processor_power_dmi_table[] = {
  86         { set_max_cstate, "Clevo 5600D", {
  87           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  88           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  89          (void *)2},
  90         { set_max_cstate, "Pavilion zv5000", {
  91           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  92           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
  93          (void *)1},
  94         { set_max_cstate, "Asus L8400B", {
  95           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  96           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
  97          (void *)1},
  98         {},
  99 };
 100
 101
 102 /*
 103  * Callers should disable interrupts before the call and enable
 104  * interrupts after return.
 105  */
 106 static void __cpuidle acpi_safe_halt(void)
 107 {
 108         if (!tif_need_resched()) {
 109                 safe_halt();
 110                 local_irq_disable();
 111         }
 112 }
 113
 114 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 115
 116 /*
 117  * Some BIOS implementations switch to C3 in the published C2 state.
 118  * This seems to be a common problem on AMD boxen, but other vendors
 119  * are affected too. We pick the most conservative approach: we assume
 120  * that the local APIC stops in both C2 and C3.
 121  */
 122 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 123                                    struct acpi_processor_cx *cx)
 124 {
 125         struct acpi_processor_power *pwr = &pr->power;
 126         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 127
 128         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 129                 return;
 130
 131         if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 132                 type = ACPI_STATE_C1;
 133
 134         /*
 135          * Check, if one of the previous states already marked the lapic
 136          * unstable
 137          */
 138         if (pwr->timer_broadcast_on_state < state)
 139                 return;
 140
 141         if (cx->type >= type)
 142                 pr->power.timer_broadcast_on_state = state;
 143 }
 144
 145 static void __lapic_timer_propagate_broadcast(void *arg)
 146 {
 147         struct acpi_processor *pr = (struct acpi_processor *) arg;
 148
 149         if (pr->power.timer_broadcast_on_state < INT_MAX)
 150                 tick_broadcast_enable();
 151         else
 152                 tick_broadcast_disable();
 153 }
 154
 155 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 156 {
 157         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 158                                  (void *)pr, 1);
 159 }
 160
 161 /* Power(C) State timer broadcast control */
 162 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 163                                         struct acpi_processor_cx *cx)
 164 {
 165         return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 166 }
 167
 168 #else
 169
 170 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 171                                    struct acpi_processor_cx *cstate) { }
 172 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 173
 174 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 175                                         struct acpi_processor_cx *cx)
 176 {
 177         return false;
 178 }
 179
 180 #endif
 181
 182 #if defined(CONFIG_X86)
 183 static void tsc_check_state(int state)
 184 {
 185         switch (boot_cpu_data.x86_vendor) {
 186         case X86_VENDOR_HYGON:
 187         case X86_VENDOR_AMD:
 188         case X86_VENDOR_INTEL:
 189         case X86_VENDOR_CENTAUR:
 190         case X86_VENDOR_ZHAOXIN:
 191                 /*
 192                  * AMD Fam10h TSC will tick in all
 193                  * C/P/S0/S1 states when this bit is set.
 194                  */
 195                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 196                         return;
 197                 fallthrough;
 198         default:
 199                 /* TSC could halt in idle, so notify users */
 200                 if (state > ACPI_STATE_C1)
 201                         mark_tsc_unstable("TSC halts in idle");
 202         }
 203 }
 204 #else
 205 static void tsc_check_state(int state) { return; }
 206 #endif
 207
 208 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 209 {
 210
 211         if (!pr->pblk)
 212                 return -ENODEV;
 213
 214         /* if info is obtained from pblk/fadt, type equals state */
 215         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 216         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 217
 218 #ifndef CONFIG_HOTPLUG_CPU
 219         /*
 220          * Check for P_LVL2_UP flag before entering C2 and above on
 221          * an SMP system.
 222          */
 223         if ((num_online_cpus() > 1) &&
 224             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 225                 return -ENODEV;
 226 #endif
 227
 228         /* determine C2 and C3 address from pblk */
 229         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 230         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 231
 232         /* determine latencies from FADT */
 233         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 234         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 235
 236         /*
 237          * FADT specified C2 latency must be less than or equal to
 238          * 100 microseconds.
 239          */
 240         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 241                 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 242                                   acpi_gbl_FADT.c2_latency);
 243                 /* invalidate C2 */
 244                 pr->power.states[ACPI_STATE_C2].address = 0;
 245         }
 246
 247         /*
 248          * FADT supplied C3 latency must be less than or equal to
 249          * 1000 microseconds.
 250          */
 251         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 252                 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 253                                   acpi_gbl_FADT.c3_latency);
 254                 /* invalidate C3 */
 255                 pr->power.states[ACPI_STATE_C3].address = 0;
 256         }
 257
 258         acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 259                           pr->power.states[ACPI_STATE_C2].address,
 260                           pr->power.states[ACPI_STATE_C3].address);
 261
 262         snprintf(pr->power.states[ACPI_STATE_C2].desc,
 263                          ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 264                          pr->power.states[ACPI_STATE_C2].address);
 265         snprintf(pr->power.states[ACPI_STATE_C3].desc,
 266                          ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 267                          pr->power.states[ACPI_STATE_C3].address);
 268
 269         return 0;
 270 }
 271
 272 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 273 {
 274         if (!pr->power.states[ACPI_STATE_C1].valid) {
 275                 /* set the first C-State to C1 */
 276                 /* all processors need to support C1 */
 277                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 278                 pr->power.states[ACPI_STATE_C1].valid = 1;
 279                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 280
 281                 snprintf(pr->power.states[ACPI_STATE_C1].desc,
 282                          ACPI_CX_DESC_LEN, "ACPI HLT");
 283         }
 284         /* the C0 state only exists as a filler in our array */
 285         pr->power.states[ACPI_STATE_C0].valid = 1;
 286         return 0;
 287 }
 288
 289 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 290 {
 291         int ret;
 292
 293         if (nocst)
 294                 return -ENODEV;
 295
 296         ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 297         if (ret)
 298                 return ret;
 299
 300         if (!pr->power.count)
 301                 return -EFAULT;
 302
 303         pr->flags.has_cst = 1;
 304         return 0;
 305 }
 306
 307 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 308                                            struct acpi_processor_cx *cx)
 309 {
 310         static int bm_check_flag = -1;
 311         static int bm_control_flag = -1;
 312
 313
 314         if (!cx->address)
 315                 return;
 316
 317         /*
 318          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 319          * DMA transfers are used by any ISA device to avoid livelock.
 320          * Note that we could disable Type-F DMA (as recommended by
 321          * the erratum), but this is known to disrupt certain ISA
 322          * devices thus we take the conservative approach.
 323          */
 324         else if (errata.piix4.fdma) {
 325                 acpi_handle_debug(pr->handle,
 326                                   "C3 not supported on PIIX4 with Type-F DMA\n");
 327                 return;
 328         }
 329
 330         /* All the logic here assumes flags.bm_check is same across all CPUs */
 331         if (bm_check_flag == -1) {
 332                 /* Determine whether bm_check is needed based on CPU  */
 333                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 334                 bm_check_flag = pr->flags.bm_check;
 335                 bm_control_flag = pr->flags.bm_control;
 336         } else {
 337                 pr->flags.bm_check = bm_check_flag;
 338                 pr->flags.bm_control = bm_control_flag;
 339         }
 340
 341         if (pr->flags.bm_check) {
 342                 if (!pr->flags.bm_control) {
 343                         if (pr->flags.has_cst != 1) {
 344                                 /* bus mastering control is necessary */
 345                                 acpi_handle_debug(pr->handle,
 346                                                   "C3 support requires BM control\n");
 347                                 return;
 348                         } else {
 349                                 /* Here we enter C3 without bus mastering */
 350                                 acpi_handle_debug(pr->handle,
 351                                                   "C3 support without BM control\n");
 352                         }
 353                 }
 354         } else {
 355                 /*
 356                  * WBINVD should be set in fadt, for C3 state to be
 357                  * supported on when bm_check is not required.
 358                  */
 359                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 360                         acpi_handle_debug(pr->handle,
 361                                           "Cache invalidation should work properly"
 362                                           " for C3 to be enabled on SMP systems\n");
 363                         return;
 364                 }
 365         }
 366
 367         /*
 368          * Otherwise we've met all of our C3 requirements.
 369          * Normalize the C3 latency to expidite policy.  Enable
 370          * checking of bus mastering status (bm_check) so we can
 371          * use this in our C3 policy
 372          */
 373         cx->valid = 1;
 374
 375         /*
 376          * On older chipsets, BM_RLD needs to be set
 377          * in order for Bus Master activity to wake the
 378          * system from C3.  Newer chipsets handle DMA
 379          * during C3 automatically and BM_RLD is a NOP.
 380          * In either case, the proper way to
 381          * handle BM_RLD is to set it and leave it set.
 382          */
 383         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 384
 385         return;
 386 }
 387
 388 static int acpi_cst_latency_cmp(const void *a, const void *b)
 389 {
 390         const struct acpi_processor_cx *x = a, *y = b;
 391
 392         if (!(x->valid && y->valid))
 393                 return 0;
 394         if (x->latency > y->latency)
 395                 return 1;
 396         if (x->latency < y->latency)
 397                 return -1;
 398         return 0;
 399 }
 400 static void acpi_cst_latency_swap(void *a, void *b, int n)
 401 {
 402         struct acpi_processor_cx *x = a, *y = b;
 403         u32 tmp;
 404
 405         if (!(x->valid && y->valid))
 406                 return;
 407         tmp = x->latency;
 408         x->latency = y->latency;
 409         y->latency = tmp;
 410 }
 411
 412 static int acpi_processor_power_verify(struct acpi_processor *pr)
 413 {
 414         unsigned int i;
 415         unsigned int working = 0;
 416         unsigned int last_latency = 0;
 417         unsigned int last_type = 0;
 418         bool buggy_latency = false;
 419
 420         pr->power.timer_broadcast_on_state = INT_MAX;
 421
 422         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 423                 struct acpi_processor_cx *cx = &pr->power.states[i];
 424
 425                 switch (cx->type) {
 426                 case ACPI_STATE_C1:
 427                         cx->valid = 1;
 428                         break;
 429
 430                 case ACPI_STATE_C2:
 431                         if (!cx->address)
 432                                 break;
 433                         cx->valid = 1;
 434                         break;
 435
 436                 case ACPI_STATE_C3:
 437                         acpi_processor_power_verify_c3(pr, cx);
 438                         break;
 439                 }
 440                 if (!cx->valid)
 441                         continue;
 442                 if (cx->type >= last_type && cx->latency < last_latency)
 443                         buggy_latency = true;
 444                 last_latency = cx->latency;
 445                 last_type = cx->type;
 446
 447                 lapic_timer_check_state(i, pr, cx);
 448                 tsc_check_state(cx->type);
 449                 working++;
 450         }
 451
 452         if (buggy_latency) {
 453                 pr_notice("FW issue: working around C-state latencies out of order\n");
 454                 sort(&pr->power.states[1], max_cstate,
 455                      sizeof(struct acpi_processor_cx),
 456                      acpi_cst_latency_cmp,
 457                      acpi_cst_latency_swap);
 458         }
 459
 460         lapic_timer_propagate_broadcast(pr);
 461
 462         return (working);
 463 }
 464
 465 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 466 {
 467         unsigned int i;
 468         int result;
 469
 470
 471         /* NOTE: the idle thread may not be running while calling
 472          * this function */
 473
 474         /* Zero initialize all the C-states info. */
 475         memset(pr->power.states, 0, sizeof(pr->power.states));
 476
 477         result = acpi_processor_get_power_info_cst(pr);
 478         if (result == -ENODEV)
 479                 result = acpi_processor_get_power_info_fadt(pr);
 480
 481         if (result)
 482                 return result;
 483
 484         acpi_processor_get_power_info_default(pr);
 485
 486         pr->power.count = acpi_processor_power_verify(pr);
 487
 488         /*
 489          * if one state of type C2 or C3 is available, mark this
 490          * CPU as being "idle manageable"
 491          */
 492         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 493                 if (pr->power.states[i].valid) {
 494                         pr->power.count = i;
 495                         pr->flags.power = 1;
 496                 }
 497         }
 498
 499         return 0;
 500 }
 501
 502 /**
 503  * acpi_idle_bm_check - checks if bus master activity was detected
 504  */
 505 static int acpi_idle_bm_check(void)
 506 {
 507         u32 bm_status = 0;
 508
 509         if (bm_check_disable)
 510                 return 0;
 511
 512         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 513         if (bm_status)
 514                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 515         /*
 516          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 517          * the true state of bus mastering activity; forcing us to
 518          * manually check the BMIDEA bit of each IDE channel.
 519          */
 520         else if (errata.piix4.bmisx) {
 521                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 522                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 523                         bm_status = 1;
 524         }
 525         return bm_status;
 526 }
 527
 528 static void wait_for_freeze(void)
 529 {
 530 #ifdef  CONFIG_X86
 531         /* No delay is needed if we are in guest */
 532         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 533                 return;
 534 #endif
 535         /* Dummy wait op - must do something useless after P_LVL2 read
 536            because chipsets cannot guarantee that STPCLK# signal
 537            gets asserted in time to freeze execution properly. */
 538         inl(acpi_gbl_FADT.xpm_timer_block.address);
 539 }
 540
 541 /**
 542  * acpi_idle_do_entry - enter idle state using the appropriate method
 543  * @cx: cstate data
 544  *
 545  * Caller disables interrupt before call and enables interrupt after return.
 546  */
 547 static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 548 {
 549         if (cx->entry_method == ACPI_CSTATE_FFH) {
 550                 /* Call into architectural FFH based C-state */
 551                 acpi_processor_ffh_cstate_enter(cx);
 552         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 553                 acpi_safe_halt();
 554         } else {
 555                 /* IO port based C-state */
 556                 inb(cx->address);
 557                 wait_for_freeze();
 558         }
 559 }
 560
 561 /**
 562  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 563  * @dev: the target CPU
 564  * @index: the index of suggested state
 565  */
 566 static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 567 {
 568         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 569
 570         ACPI_FLUSH_CPU_CACHE();
 571
 572         while (1) {
 573
 574                 if (cx->entry_method == ACPI_CSTATE_HALT)
 575                         safe_halt();
 576                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 577                         inb(cx->address);
 578                         wait_for_freeze();
 579                 } else
 580                         return -ENODEV;
 581
 582 #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
 583                 cond_wakeup_cpu0();
 584 #endif
 585         }
 586
 587         /* Never reached */
 588         return 0;
 589 }
 590
 591 static bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 592 {
 593         return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 594                 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 595 }
 596
 597 static int c3_cpu_count;
 598 static DEFINE_RAW_SPINLOCK(c3_lock);
 599
 600 /**
 601  * acpi_idle_enter_bm - enters C3 with proper BM handling
 602  * @drv: cpuidle driver
 603  * @pr: Target processor
 604  * @cx: Target state context
 605  * @index: index of target state
 606  */
 607 static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
 608                                struct acpi_processor *pr,
 609                                struct acpi_processor_cx *cx,
 610                                int index)
 611 {
 612         static struct acpi_processor_cx safe_cx = {
 613                 .entry_method = ACPI_CSTATE_HALT,
 614         };
 615
 616         /*
 617          * disable bus master
 618          * bm_check implies we need ARB_DIS
 619          * bm_control implies whether we can do ARB_DIS
 620          *
 621          * That leaves a case where bm_check is set and bm_control is not set.
 622          * In that case we cannot do much, we enter C3 without doing anything.
 623          */
 624         bool dis_bm = pr->flags.bm_control;
 625
 626         /* If we can skip BM, demote to a safe state. */
 627         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 628                 dis_bm = false;
 629                 index = drv->safe_state_index;
 630                 if (index >= 0) {
 631                         cx = this_cpu_read(acpi_cstate[index]);
 632                 } else {
 633                         cx = &safe_cx;
 634                         index = -EBUSY;
 635                 }
 636         }
 637
 638         if (dis_bm) {
 639                 raw_spin_lock(&c3_lock);
 640                 c3_cpu_count++;
 641                 /* Disable bus master arbitration when all CPUs are in C3 */
 642                 if (c3_cpu_count == num_online_cpus())
 643                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 644                 raw_spin_unlock(&c3_lock);
 645         }
 646
 647         rcu_idle_enter();
 648
 649         acpi_idle_do_entry(cx);
 650
 651         rcu_idle_exit();
 652
 653         /* Re-enable bus master arbitration */
 654         if (dis_bm) {
 655                 raw_spin_lock(&c3_lock);
 656                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 657                 c3_cpu_count--;
 658                 raw_spin_unlock(&c3_lock);
 659         }
 660
 661         return index;
 662 }
 663
 664 static int acpi_idle_enter(struct cpuidle_device *dev,
 665                            struct cpuidle_driver *drv, int index)
 666 {
 667         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 668         struct acpi_processor *pr;
 669
 670         pr = __this_cpu_read(processors);
 671         if (unlikely(!pr))
 672                 return -EINVAL;
 673
 674         if (cx->type != ACPI_STATE_C1) {
 675                 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 676                         return acpi_idle_enter_bm(drv, pr, cx, index);
 677
 678                 /* C2 to C1 demotion. */
 679                 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 680                         index = ACPI_IDLE_STATE_START;
 681                         cx = per_cpu(acpi_cstate[index], dev->cpu);
 682                 }
 683         }
 684
 685         if (cx->type == ACPI_STATE_C3)
 686                 ACPI_FLUSH_CPU_CACHE();
 687
 688         acpi_idle_do_entry(cx);
 689
 690         return index;
 691 }
 692
 693 static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 694                                   struct cpuidle_driver *drv, int index)
 695 {
 696         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 697
 698         if (cx->type == ACPI_STATE_C3) {
 699                 struct acpi_processor *pr = __this_cpu_read(processors);
 700
 701                 if (unlikely(!pr))
 702                         return 0;
 703
 704                 if (pr->flags.bm_check) {
 705                         u8 bm_sts_skip = cx->bm_sts_skip;
 706
 707                         /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 708                         cx->bm_sts_skip = 1;
 709                         acpi_idle_enter_bm(drv, pr, cx, index);
 710                         cx->bm_sts_skip = bm_sts_skip;
 711
 712                         return 0;
 713                 } else {
 714                         ACPI_FLUSH_CPU_CACHE();
 715                 }
 716         }
 717         acpi_idle_do_entry(cx);
 718
 719         return 0;
 720 }
 721
 722 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 723                                            struct cpuidle_device *dev)
 724 {
 725         int i, count = ACPI_IDLE_STATE_START;
 726         struct acpi_processor_cx *cx;
 727         struct cpuidle_state *state;
 728
 729         if (max_cstate == 0)
 730                 max_cstate = 1;
 731
 732         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 733                 state = &acpi_idle_driver.states[count];
 734                 cx = &pr->power.states[i];
 735
 736                 if (!cx->valid)
 737                         continue;
 738
 739                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
 740
 741                 if (lapic_timer_needs_broadcast(pr, cx))
 742                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 743
 744                 if (cx->type == ACPI_STATE_C3) {
 745                         state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 746                         if (pr->flags.bm_check)
 747                                 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 748                 }
 749
 750                 count++;
 751                 if (count == CPUIDLE_STATE_MAX)
 752                         break;
 753         }
 754
 755         if (!count)
 756                 return -EINVAL;
 757
 758         return 0;
 759 }
 760
 761 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 762 {
 763         int i, count;
 764         struct acpi_processor_cx *cx;
 765         struct cpuidle_state *state;
 766         struct cpuidle_driver *drv = &acpi_idle_driver;
 767
 768         if (max_cstate == 0)
 769                 max_cstate = 1;
 770
 771         if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 772                 cpuidle_poll_state_init(drv);
 773                 count = 1;
 774         } else {
 775                 count = 0;
 776         }
 777
 778         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 779                 cx = &pr->power.states[i];
 780
 781                 if (!cx->valid)
 782                         continue;
 783
 784                 state = &drv->states[count];
 785                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 786                 strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 787                 state->exit_latency = cx->latency;
 788                 state->target_residency = cx->latency * latency_factor;
 789                 state->enter = acpi_idle_enter;
 790
 791                 state->flags = 0;
 792                 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {
 793                         state->enter_dead = acpi_idle_play_dead;
 794                         drv->safe_state_index = count;
 795                 }
 796                 /*
 797                  * Halt-induced C1 is not good for ->enter_s2idle, because it
 798                  * re-enables interrupts on exit.  Moreover, C1 is generally not
 799                  * particularly interesting from the suspend-to-idle angle, so
 800                  * avoid C1 and the situations in which we may need to fall back
 801                  * to it altogether.
 802                  */
 803                 if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
 804                         state->enter_s2idle = acpi_idle_enter_s2idle;
 805
 806                 count++;
 807                 if (count == CPUIDLE_STATE_MAX)
 808                         break;
 809         }
 810
 811         drv->state_count = count;
 812
 813         if (!count)
 814                 return -EINVAL;
 815
 816         return 0;
 817 }
 818
 819 static inline void acpi_processor_cstate_first_run_checks(void)
 820 {
 821         static int first_run;
 822
 823         if (first_run)
 824                 return;
 825         dmi_check_system(processor_power_dmi_table);
 826         max_cstate = acpi_processor_cstate_check(max_cstate);
 827         if (max_cstate < ACPI_C_STATES_MAX)
 828                 pr_notice("processor limited to max C-state %d\n", max_cstate);
 829
 830         first_run++;
 831
 832         if (nocst)
 833                 return;
 834
 835         acpi_processor_claim_cst_control();
 836 }
 837 #else
 838
 839 static inline int disabled_by_idle_boot_param(void) { return 0; }
 840 static inline void acpi_processor_cstate_first_run_checks(void) { }
 841 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 842 {
 843         return -ENODEV;
 844 }
 845
 846 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 847                                            struct cpuidle_device *dev)
 848 {
 849         return -EINVAL;
 850 }
 851
 852 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 853 {
 854         return -EINVAL;
 855 }
 856
 857 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 858
 859 struct acpi_lpi_states_array {
 860         unsigned int size;
 861         unsigned int composite_states_size;
 862         struct acpi_lpi_state *entries;
 863         struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
 864 };
 865
 866 static int obj_get_integer(union acpi_object *obj, u32 *value)
 867 {
 868         if (obj->type != ACPI_TYPE_INTEGER)
 869                 return -EINVAL;
 870
 871         *value = obj->integer.value;
 872         return 0;
 873 }
 874
 875 static int acpi_processor_evaluate_lpi(acpi_handle handle,
 876                                        struct acpi_lpi_states_array *info)
 877 {
 878         acpi_status status;
 879         int ret = 0;
 880         int pkg_count, state_idx = 1, loop;
 881         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 882         union acpi_object *lpi_data;
 883         struct acpi_lpi_state *lpi_state;
 884
 885         status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
 886         if (ACPI_FAILURE(status)) {
 887                 acpi_handle_debug(handle, "No _LPI, giving up\n");
 888                 return -ENODEV;
 889         }
 890
 891         lpi_data = buffer.pointer;
 892
 893         /* There must be at least 4 elements = 3 elements + 1 package */
 894         if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
 895             lpi_data->package.count < 4) {
 896                 pr_debug("not enough elements in _LPI\n");
 897                 ret = -ENODATA;
 898                 goto end;
 899         }
 900
 901         pkg_count = lpi_data->package.elements[2].integer.value;
 902
 903         /* Validate number of power states. */
 904         if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
 905                 pr_debug("count given by _LPI is not valid\n");
 906                 ret = -ENODATA;
 907                 goto end;
 908         }
 909
 910         lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
 911         if (!lpi_state) {
 912                 ret = -ENOMEM;
 913                 goto end;
 914         }
 915
 916         info->size = pkg_count;
 917         info->entries = lpi_state;
 918
 919         /* LPI States start at index 3 */
 920         for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
 921                 union acpi_object *element, *pkg_elem, *obj;
 922
 923                 element = &lpi_data->package.elements[loop];
 924                 if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
 925                         continue;
 926
 927                 pkg_elem = element->package.elements;
 928
 929                 obj = pkg_elem + 6;
 930                 if (obj->type == ACPI_TYPE_BUFFER) {
 931                         struct acpi_power_register *reg;
 932
 933                         reg = (struct acpi_power_register *)obj->buffer.pointer;
 934                         if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 935                             reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
 936                                 continue;
 937
 938                         lpi_state->address = reg->address;
 939                         lpi_state->entry_method =
 940                                 reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
 941                                 ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
 942                 } else if (obj->type == ACPI_TYPE_INTEGER) {
 943                         lpi_state->entry_method = ACPI_CSTATE_INTEGER;
 944                         lpi_state->address = obj->integer.value;
 945                 } else {
 946                         continue;
 947                 }
 948
 949                 /* elements[7,8] skipped for now i.e. Residency/Usage counter*/
 950
 951                 obj = pkg_elem + 9;
 952                 if (obj->type == ACPI_TYPE_STRING)
 953                         strlcpy(lpi_state->desc, obj->string.pointer,
 954                                 ACPI_CX_DESC_LEN);
 955
 956                 lpi_state->index = state_idx;
 957                 if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
 958                         pr_debug("No min. residency found, assuming 10 us\n");
 959                         lpi_state->min_residency = 10;
 960                 }
 961
 962                 if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
 963                         pr_debug("No wakeup residency found, assuming 10 us\n");
 964                         lpi_state->wake_latency = 10;
 965                 }
 966
 967                 if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
 968                         lpi_state->flags = 0;
 969
 970                 if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
 971                         lpi_state->arch_flags = 0;
 972
 973                 if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
 974                         lpi_state->res_cnt_freq = 1;
 975
 976                 if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
 977                         lpi_state->enable_parent_state = 0;
 978         }
 979
 980         acpi_handle_debug(handle, "Found %d power states\n", state_idx);
 981 end:
 982         kfree(buffer.pointer);
 983         return ret;
 984 }
 985
 986 /*
 987  * flat_state_cnt - the number of composite LPI states after the process of flattening
 988  */
 989 static int flat_state_cnt;
 990
 991 /**
 992  * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
 993  *
 994  * @local: local LPI state
 995  * @parent: parent LPI state
 996  * @result: composite LPI state
 997  */
 998 static bool combine_lpi_states(struct acpi_lpi_state *local,
 999                                struct acpi_lpi_state *parent,
1000                                struct acpi_lpi_state *result)
1001 {
1002         if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1003                 if (!parent->address) /* 0 means autopromotable */
1004                         return false;
1005                 result->address = local->address + parent->address;
1006         } else {
1007                 result->address = parent->address;
1008         }
1009
1010         result->min_residency = max(local->min_residency, parent->min_residency);
1011         result->wake_latency = local->wake_latency + parent->wake_latency;
1012         result->enable_parent_state = parent->enable_parent_state;
1013         result->entry_method = local->entry_method;
1014
1015         result->flags = parent->flags;
1016         result->arch_flags = parent->arch_flags;
1017         result->index = parent->index;
1018
1019         strlcpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
1020         strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
1021         strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
1022         return true;
1023 }
1024
1025 #define ACPI_LPI_STATE_FLAGS_ENABLED                    BIT(0)
1026
1027 static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1028                                   struct acpi_lpi_state *t)
1029 {
1030         curr_level->composite_states[curr_level->composite_states_size++] = t;
1031 }
1032
1033 static int flatten_lpi_states(struct acpi_processor *pr,
1034                               struct acpi_lpi_states_array *curr_level,
1035                               struct acpi_lpi_states_array *prev_level)
1036 {
1037         int i, j, state_count = curr_level->size;
1038         struct acpi_lpi_state *p, *t = curr_level->entries;
1039
1040         curr_level->composite_states_size = 0;
1041         for (j = 0; j < state_count; j++, t++) {
1042                 struct acpi_lpi_state *flpi;
1043
1044                 if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1045                         continue;
1046
1047                 if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1048                         pr_warn("Limiting number of LPI states to max (%d)\n",
1049                                 ACPI_PROCESSOR_MAX_POWER);
1050                         pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1051                         break;
1052                 }
1053
1054                 flpi = &pr->power.lpi_states[flat_state_cnt];
1055
1056                 if (!prev_level) { /* leaf/processor node */
1057                         memcpy(flpi, t, sizeof(*t));
1058                         stash_composite_state(curr_level, flpi);
1059                         flat_state_cnt++;
1060                         continue;
1061                 }
1062
1063                 for (i = 0; i < prev_level->composite_states_size; i++) {
1064                         p = prev_level->composite_states[i];
1065                         if (t->index <= p->enable_parent_state &&
1066                             combine_lpi_states(p, t, flpi)) {
1067                                 stash_composite_state(curr_level, flpi);
1068                                 flat_state_cnt++;
1069                                 flpi++;
1070                         }
1071                 }
1072         }
1073
1074         kfree(curr_level->entries);
1075         return 0;
1076 }
1077
1078 static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1079 {
1080         int ret, i;
1081         acpi_status status;
1082         acpi_handle handle = pr->handle, pr_ahandle;
1083         struct acpi_device *d = NULL;
1084         struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1085
1086         if (!osc_pc_lpi_support_confirmed)
1087                 return -EOPNOTSUPP;
1088
1089         if (!acpi_has_method(handle, "_LPI"))
1090                 return -EINVAL;
1091
1092         flat_state_cnt = 0;
1093         prev = &info[0];
1094         curr = &info[1];
1095         handle = pr->handle;
1096         ret = acpi_processor_evaluate_lpi(handle, prev);
1097         if (ret)
1098                 return ret;
1099         flatten_lpi_states(pr, prev, NULL);
1100
1101         status = acpi_get_parent(handle, &pr_ahandle);
1102         while (ACPI_SUCCESS(status)) {
1103                 acpi_bus_get_device(pr_ahandle, &d);
1104                 handle = pr_ahandle;
1105
1106                 if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
1107                         break;
1108
1109                 /* can be optional ? */
1110                 if (!acpi_has_method(handle, "_LPI"))
1111                         break;
1112
1113                 ret = acpi_processor_evaluate_lpi(handle, curr);
1114                 if (ret)
1115                         break;
1116
1117                 /* flatten all the LPI states in this level of hierarchy */
1118                 flatten_lpi_states(pr, curr, prev);
1119
1120                 tmp = prev, prev = curr, curr = tmp;
1121
1122                 status = acpi_get_parent(handle, &pr_ahandle);
1123         }
1124
1125         pr->power.count = flat_state_cnt;
1126         /* reset the index after flattening */
1127         for (i = 0; i < pr->power.count; i++)
1128                 pr->power.lpi_states[i].index = i;
1129
1130         /* Tell driver that _LPI is supported. */
1131         pr->flags.has_lpi = 1;
1132         pr->flags.power = 1;
1133
1134         return 0;
1135 }
1136
1137 int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1138 {
1139         return -ENODEV;
1140 }
1141
1142 int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1143 {
1144         return -ENODEV;
1145 }
1146
1147 /**
1148  * acpi_idle_lpi_enter - enters an ACPI any LPI state
1149  * @dev: the target CPU
1150  * @drv: cpuidle driver containing cpuidle state info
1151  * @index: index of target state
1152  *
1153  * Return: 0 for success or negative value for error
1154  */
1155 static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1156                                struct cpuidle_driver *drv, int index)
1157 {
1158         struct acpi_processor *pr;
1159         struct acpi_lpi_state *lpi;
1160
1161         pr = __this_cpu_read(processors);
1162
1163         if (unlikely(!pr))
1164                 return -EINVAL;
1165
1166         lpi = &pr->power.lpi_states[index];
1167         if (lpi->entry_method == ACPI_CSTATE_FFH)
1168                 return acpi_processor_ffh_lpi_enter(lpi);
1169
1170         return -EINVAL;
1171 }
1172
1173 static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1174 {
1175         int i;
1176         struct acpi_lpi_state *lpi;
1177         struct cpuidle_state *state;
1178         struct cpuidle_driver *drv = &acpi_idle_driver;
1179
1180         if (!pr->flags.has_lpi)
1181                 return -EOPNOTSUPP;
1182
1183         for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1184                 lpi = &pr->power.lpi_states[i];
1185
1186                 state = &drv->states[i];
1187                 snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
1188                 strlcpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
1189                 state->exit_latency = lpi->wake_latency;
1190                 state->target_residency = lpi->min_residency;
1191                 if (lpi->arch_flags)
1192                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
1193                 state->enter = acpi_idle_lpi_enter;
1194                 drv->safe_state_index = i;
1195         }
1196
1197         drv->state_count = i;
1198
1199         return 0;
1200 }
1201
1202 /**
1203  * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1204  * global state data i.e. idle routines
1205  *
1206  * @pr: the ACPI processor
1207  */
1208 static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1209 {
1210         int i;
1211         struct cpuidle_driver *drv = &acpi_idle_driver;
1212
1213         if (!pr->flags.power_setup_done || !pr->flags.power)
1214                 return -EINVAL;
1215
1216         drv->safe_state_index = -1;
1217         for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1218                 drv->states[i].name[0] = '\0';
1219                 drv->states[i].desc[0] = '\0';
1220         }
1221
1222         if (pr->flags.has_lpi)
1223                 return acpi_processor_setup_lpi_states(pr);
1224
1225         return acpi_processor_setup_cstates(pr);
1226 }
1227
1228 /**
1229  * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1230  * device i.e. per-cpu data
1231  *
1232  * @pr: the ACPI processor
1233  * @dev : the cpuidle device
1234  */
1235 static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1236                                             struct cpuidle_device *dev)
1237 {
1238         if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1239                 return -EINVAL;
1240
1241         dev->cpu = pr->id;
1242         if (pr->flags.has_lpi)
1243                 return acpi_processor_ffh_lpi_probe(pr->id);
1244
1245         return acpi_processor_setup_cpuidle_cx(pr, dev);
1246 }
1247
1248 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1249 {
1250         int ret;
1251
1252         ret = acpi_processor_get_lpi_info(pr);
1253         if (ret)
1254                 ret = acpi_processor_get_cstate_info(pr);
1255
1256         return ret;
1257 }
1258
1259 int acpi_processor_hotplug(struct acpi_processor *pr)
1260 {
1261         int ret = 0;
1262         struct cpuidle_device *dev;
1263
1264         if (disabled_by_idle_boot_param())
1265                 return 0;
1266
1267         if (!pr->flags.power_setup_done)
1268                 return -ENODEV;
1269
1270         dev = per_cpu(acpi_cpuidle_device, pr->id);
1271         cpuidle_pause_and_lock();
1272         cpuidle_disable_device(dev);
1273         ret = acpi_processor_get_power_info(pr);
1274         if (!ret && pr->flags.power) {
1275                 acpi_processor_setup_cpuidle_dev(pr, dev);
1276                 ret = cpuidle_enable_device(dev);
1277         }
1278         cpuidle_resume_and_unlock();
1279
1280         return ret;
1281 }
1282
1283 int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1284 {
1285         int cpu;
1286         struct acpi_processor *_pr;
1287         struct cpuidle_device *dev;
1288
1289         if (disabled_by_idle_boot_param())
1290                 return 0;
1291
1292         if (!pr->flags.power_setup_done)
1293                 return -ENODEV;
1294
1295         /*
1296          * FIXME:  Design the ACPI notification to make it once per
1297          * system instead of once per-cpu.  This condition is a hack
1298          * to make the code that updates C-States be called once.
1299          */
1300
1301         if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1302
1303                 /* Protect against cpu-hotplug */
1304                 cpus_read_lock();
1305                 cpuidle_pause_and_lock();
1306
1307                 /* Disable all cpuidle devices */
1308                 for_each_online_cpu(cpu) {
1309                         _pr = per_cpu(processors, cpu);
1310                         if (!_pr || !_pr->flags.power_setup_done)
1311                                 continue;
1312                         dev = per_cpu(acpi_cpuidle_device, cpu);
1313                         cpuidle_disable_device(dev);
1314                 }
1315
1316                 /* Populate Updated C-state information */
1317                 acpi_processor_get_power_info(pr);
1318                 acpi_processor_setup_cpuidle_states(pr);
1319
1320                 /* Enable all cpuidle devices */
1321                 for_each_online_cpu(cpu) {
1322                         _pr = per_cpu(processors, cpu);
1323                         if (!_pr || !_pr->flags.power_setup_done)
1324                                 continue;
1325                         acpi_processor_get_power_info(_pr);
1326                         if (_pr->flags.power) {
1327                                 dev = per_cpu(acpi_cpuidle_device, cpu);
1328                                 acpi_processor_setup_cpuidle_dev(_pr, dev);
1329                                 cpuidle_enable_device(dev);
1330                         }
1331                 }
1332                 cpuidle_resume_and_unlock();
1333                 cpus_read_unlock();
1334         }
1335
1336         return 0;
1337 }
1338
1339 static int acpi_processor_registered;
1340
1341 int acpi_processor_power_init(struct acpi_processor *pr)
1342 {
1343         int retval;
1344         struct cpuidle_device *dev;
1345
1346         if (disabled_by_idle_boot_param())
1347                 return 0;
1348
1349         acpi_processor_cstate_first_run_checks();
1350
1351         if (!acpi_processor_get_power_info(pr))
1352                 pr->flags.power_setup_done = 1;
1353
1354         /*
1355          * Install the idle handler if processor power management is supported.
1356          * Note that we use previously set idle handler will be used on
1357          * platforms that only support C1.
1358          */
1359         if (pr->flags.power) {
1360                 /* Register acpi_idle_driver if not already registered */
1361                 if (!acpi_processor_registered) {
1362                         acpi_processor_setup_cpuidle_states(pr);
1363                         retval = cpuidle_register_driver(&acpi_idle_driver);
1364                         if (retval)
1365                                 return retval;
1366                         pr_debug("%s registered with cpuidle\n",
1367                                  acpi_idle_driver.name);
1368                 }
1369
1370                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1371                 if (!dev)
1372                         return -ENOMEM;
1373                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1374
1375                 acpi_processor_setup_cpuidle_dev(pr, dev);
1376
1377                 /* Register per-cpu cpuidle_device. Cpuidle driver
1378                  * must already be registered before registering device
1379                  */
1380                 retval = cpuidle_register_device(dev);
1381                 if (retval) {
1382                         if (acpi_processor_registered == 0)
1383                                 cpuidle_unregister_driver(&acpi_idle_driver);
1384                         return retval;
1385                 }
1386                 acpi_processor_registered++;
1387         }
1388         return 0;
1389 }
1390
1391 int acpi_processor_power_exit(struct acpi_processor *pr)
1392 {
1393         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1394
1395         if (disabled_by_idle_boot_param())
1396                 return 0;
1397
1398         if (pr->flags.power) {
1399                 cpuidle_unregister_device(dev);
1400                 acpi_processor_registered--;
1401                 if (acpi_processor_registered == 0)
1402                         cpuidle_unregister_driver(&acpi_idle_driver);
1403         }
1404
1405         pr->flags.power_setup_done = 0;
1406         return 0;
1407 }