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 <linux/minmax.h>
  24 #include <acpi/processor.h>
  25
  26 /*
  27  * Include the apic definitions for x86 to have the APIC timer related defines
  28  * available also for UP (on SMP it gets magically included via linux/smp.h).
  29  * asm/acpi.h is not an option, as it would require more include magic. Also
  30  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  31  */
  32 #ifdef CONFIG_X86
  33 #include <asm/apic.h>
  34 #include <asm/cpu.h>
  35 #endif
  36
  37 #define ACPI_IDLE_STATE_START   (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  38
  39 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  40 module_param(max_cstate, uint, 0000);
  41 static unsigned int nocst __read_mostly;
  42 module_param(nocst, uint, 0000);
  43 static int bm_check_disable __read_mostly;
  44 module_param(bm_check_disable, uint, 0000);
  45
  46 static unsigned int latency_factor __read_mostly = 2;
  47 module_param(latency_factor, uint, 0644);
  48
  49 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  50
  51 struct cpuidle_driver acpi_idle_driver = {
  52         .name =         "acpi_idle",
  53         .owner =        THIS_MODULE,
  54 };
  55
  56 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  57 static
  58 DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  59
  60 static int disabled_by_idle_boot_param(void)
  61 {
  62         return boot_option_idle_override == IDLE_POLL ||
  63                 boot_option_idle_override == IDLE_HALT;
  64 }
  65
  66 /*
  67  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  68  * For now disable this. Probably a bug somewhere else.
  69  *
  70  * To skip this limit, boot/load with a large max_cstate limit.
  71  */
  72 static int set_max_cstate(const struct dmi_system_id *id)
  73 {
  74         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  75                 return 0;
  76
  77         pr_notice("%s detected - limiting to C%ld max_cstate."
  78                   " Override with \"processor.max_cstate=%d\"\n", id->ident,
  79                   (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  80
  81         max_cstate = (long)id->driver_data;
  82
  83         return 0;
  84 }
  85
  86 static const struct dmi_system_id processor_power_dmi_table[] = {
  87         { set_max_cstate, "Clevo 5600D", {
  88           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  89           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  90          (void *)2},
  91         { set_max_cstate, "Pavilion zv5000", {
  92           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  93           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
  94          (void *)1},
  95         { set_max_cstate, "Asus L8400B", {
  96           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  97           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
  98          (void *)1},
  99         {},
 100 };
 101
 102
 103 /*
 104  * Callers should disable interrupts before the call and enable
 105  * interrupts after return.
 106  */
 107 static void __cpuidle acpi_safe_halt(void)
 108 {
 109         if (!tif_need_resched()) {
 110                 safe_halt();
 111                 local_irq_disable();
 112         }
 113 }
 114
 115 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 116
 117 /*
 118  * Some BIOS implementations switch to C3 in the published C2 state.
 119  * This seems to be a common problem on AMD boxen, but other vendors
 120  * are affected too. We pick the most conservative approach: we assume
 121  * that the local APIC stops in both C2 and C3.
 122  */
 123 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 124                                    struct acpi_processor_cx *cx)
 125 {
 126         struct acpi_processor_power *pwr = &pr->power;
 127         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 128
 129         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 130                 return;
 131
 132         if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 133                 type = ACPI_STATE_C1;
 134
 135         /*
 136          * Check, if one of the previous states already marked the lapic
 137          * unstable
 138          */
 139         if (pwr->timer_broadcast_on_state < state)
 140                 return;
 141
 142         if (cx->type >= type)
 143                 pr->power.timer_broadcast_on_state = state;
 144 }
 145
 146 static void __lapic_timer_propagate_broadcast(void *arg)
 147 {
 148         struct acpi_processor *pr = (struct acpi_processor *) arg;
 149
 150         if (pr->power.timer_broadcast_on_state < INT_MAX)
 151                 tick_broadcast_enable();
 152         else
 153                 tick_broadcast_disable();
 154 }
 155
 156 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 157 {
 158         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 159                                  (void *)pr, 1);
 160 }
 161
 162 /* Power(C) State timer broadcast control */
 163 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 164                                         struct acpi_processor_cx *cx)
 165 {
 166         return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 167 }
 168
 169 #else
 170
 171 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 172                                    struct acpi_processor_cx *cstate) { }
 173 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 174
 175 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 176                                         struct acpi_processor_cx *cx)
 177 {
 178         return false;
 179 }
 180
 181 #endif
 182
 183 #if defined(CONFIG_X86)
 184 static void tsc_check_state(int state)
 185 {
 186         switch (boot_cpu_data.x86_vendor) {
 187         case X86_VENDOR_HYGON:
 188         case X86_VENDOR_AMD:
 189         case X86_VENDOR_INTEL:
 190         case X86_VENDOR_CENTAUR:
 191         case X86_VENDOR_ZHAOXIN:
 192                 /*
 193                  * AMD Fam10h TSC will tick in all
 194                  * C/P/S0/S1 states when this bit is set.
 195                  */
 196                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 197                         return;
 198                 fallthrough;
 199         default:
 200                 /* TSC could halt in idle, so notify users */
 201                 if (state > ACPI_STATE_C1)
 202                         mark_tsc_unstable("TSC halts in idle");
 203         }
 204 }
 205 #else
 206 static void tsc_check_state(int state) { return; }
 207 #endif
 208
 209 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 210 {
 211
 212         if (!pr->pblk)
 213                 return -ENODEV;
 214
 215         /* if info is obtained from pblk/fadt, type equals state */
 216         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 217         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 218
 219 #ifndef CONFIG_HOTPLUG_CPU
 220         /*
 221          * Check for P_LVL2_UP flag before entering C2 and above on
 222          * an SMP system.
 223          */
 224         if ((num_online_cpus() > 1) &&
 225             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 226                 return -ENODEV;
 227 #endif
 228
 229         /* determine C2 and C3 address from pblk */
 230         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 231         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 232
 233         /* determine latencies from FADT */
 234         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 235         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 236
 237         /*
 238          * FADT specified C2 latency must be less than or equal to
 239          * 100 microseconds.
 240          */
 241         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 242                 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 243                                   acpi_gbl_FADT.c2_latency);
 244                 /* invalidate C2 */
 245                 pr->power.states[ACPI_STATE_C2].address = 0;
 246         }
 247
 248         /*
 249          * FADT supplied C3 latency must be less than or equal to
 250          * 1000 microseconds.
 251          */
 252         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 253                 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 254                                   acpi_gbl_FADT.c3_latency);
 255                 /* invalidate C3 */
 256                 pr->power.states[ACPI_STATE_C3].address = 0;
 257         }
 258
 259         acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 260                           pr->power.states[ACPI_STATE_C2].address,
 261                           pr->power.states[ACPI_STATE_C3].address);
 262
 263         snprintf(pr->power.states[ACPI_STATE_C2].desc,
 264                          ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 265                          pr->power.states[ACPI_STATE_C2].address);
 266         snprintf(pr->power.states[ACPI_STATE_C3].desc,
 267                          ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 268                          pr->power.states[ACPI_STATE_C3].address);
 269
 270         return 0;
 271 }
 272
 273 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 274 {
 275         if (!pr->power.states[ACPI_STATE_C1].valid) {
 276                 /* set the first C-State to C1 */
 277                 /* all processors need to support C1 */
 278                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 279                 pr->power.states[ACPI_STATE_C1].valid = 1;
 280                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 281
 282                 snprintf(pr->power.states[ACPI_STATE_C1].desc,
 283                          ACPI_CX_DESC_LEN, "ACPI HLT");
 284         }
 285         /* the C0 state only exists as a filler in our array */
 286         pr->power.states[ACPI_STATE_C0].valid = 1;
 287         return 0;
 288 }
 289
 290 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 291 {
 292         int ret;
 293
 294         if (nocst)
 295                 return -ENODEV;
 296
 297         ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 298         if (ret)
 299                 return ret;
 300
 301         if (!pr->power.count)
 302                 return -EFAULT;
 303
 304         pr->flags.has_cst = 1;
 305         return 0;
 306 }
 307
 308 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 309                                            struct acpi_processor_cx *cx)
 310 {
 311         static int bm_check_flag = -1;
 312         static int bm_control_flag = -1;
 313
 314
 315         if (!cx->address)
 316                 return;
 317
 318         /*
 319          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 320          * DMA transfers are used by any ISA device to avoid livelock.
 321          * Note that we could disable Type-F DMA (as recommended by
 322          * the erratum), but this is known to disrupt certain ISA
 323          * devices thus we take the conservative approach.
 324          */
 325         else if (errata.piix4.fdma) {
 326                 acpi_handle_debug(pr->handle,
 327                                   "C3 not supported on PIIX4 with Type-F DMA\n");
 328                 return;
 329         }
 330
 331         /* All the logic here assumes flags.bm_check is same across all CPUs */
 332         if (bm_check_flag == -1) {
 333                 /* Determine whether bm_check is needed based on CPU  */
 334                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 335                 bm_check_flag = pr->flags.bm_check;
 336                 bm_control_flag = pr->flags.bm_control;
 337         } else {
 338                 pr->flags.bm_check = bm_check_flag;
 339                 pr->flags.bm_control = bm_control_flag;
 340         }
 341
 342         if (pr->flags.bm_check) {
 343                 if (!pr->flags.bm_control) {
 344                         if (pr->flags.has_cst != 1) {
 345                                 /* bus mastering control is necessary */
 346                                 acpi_handle_debug(pr->handle,
 347                                                   "C3 support requires BM control\n");
 348                                 return;
 349                         } else {
 350                                 /* Here we enter C3 without bus mastering */
 351                                 acpi_handle_debug(pr->handle,
 352                                                   "C3 support without BM control\n");
 353                         }
 354                 }
 355         } else {
 356                 /*
 357                  * WBINVD should be set in fadt, for C3 state to be
 358                  * supported on when bm_check is not required.
 359                  */
 360                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 361                         acpi_handle_debug(pr->handle,
 362                                           "Cache invalidation should work properly"
 363                                           " for C3 to be enabled on SMP systems\n");
 364                         return;
 365                 }
 366         }
 367
 368         /*
 369          * Otherwise we've met all of our C3 requirements.
 370          * Normalize the C3 latency to expidite policy.  Enable
 371          * checking of bus mastering status (bm_check) so we can
 372          * use this in our C3 policy
 373          */
 374         cx->valid = 1;
 375
 376         /*
 377          * On older chipsets, BM_RLD needs to be set
 378          * in order for Bus Master activity to wake the
 379          * system from C3.  Newer chipsets handle DMA
 380          * during C3 automatically and BM_RLD is a NOP.
 381          * In either case, the proper way to
 382          * handle BM_RLD is to set it and leave it set.
 383          */
 384         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 385
 386         return;
 387 }
 388
 389 static int acpi_cst_latency_cmp(const void *a, const void *b)
 390 {
 391         const struct acpi_processor_cx *x = a, *y = b;
 392
 393         if (!(x->valid && y->valid))
 394                 return 0;
 395         if (x->latency > y->latency)
 396                 return 1;
 397         if (x->latency < y->latency)
 398                 return -1;
 399         return 0;
 400 }
 401 static void acpi_cst_latency_swap(void *a, void *b, int n)
 402 {
 403         struct acpi_processor_cx *x = a, *y = b;
 404
 405         if (!(x->valid && y->valid))
 406                 return;
 407         swap(x->latency, y->latency);
 408 }
 409
 410 static int acpi_processor_power_verify(struct acpi_processor *pr)
 411 {
 412         unsigned int i;
 413         unsigned int working = 0;
 414         unsigned int last_latency = 0;
 415         unsigned int last_type = 0;
 416         bool buggy_latency = false;
 417
 418         pr->power.timer_broadcast_on_state = INT_MAX;
 419
 420         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 421                 struct acpi_processor_cx *cx = &pr->power.states[i];
 422
 423                 switch (cx->type) {
 424                 case ACPI_STATE_C1:
 425                         cx->valid = 1;
 426                         break;
 427
 428                 case ACPI_STATE_C2:
 429                         if (!cx->address)
 430                                 break;
 431                         cx->valid = 1;
 432                         break;
 433
 434                 case ACPI_STATE_C3:
 435                         acpi_processor_power_verify_c3(pr, cx);
 436                         break;
 437                 }
 438                 if (!cx->valid)
 439                         continue;
 440                 if (cx->type >= last_type && cx->latency < last_latency)
 441                         buggy_latency = true;
 442                 last_latency = cx->latency;
 443                 last_type = cx->type;
 444
 445                 lapic_timer_check_state(i, pr, cx);
 446                 tsc_check_state(cx->type);
 447                 working++;
 448         }
 449
 450         if (buggy_latency) {
 451                 pr_notice("FW issue: working around C-state latencies out of order\n");
 452                 sort(&pr->power.states[1], max_cstate,
 453                      sizeof(struct acpi_processor_cx),
 454                      acpi_cst_latency_cmp,
 455                      acpi_cst_latency_swap);
 456         }
 457
 458         lapic_timer_propagate_broadcast(pr);
 459
 460         return (working);
 461 }
 462
 463 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 464 {
 465         unsigned int i;
 466         int result;
 467
 468
 469         /* NOTE: the idle thread may not be running while calling
 470          * this function */
 471
 472         /* Zero initialize all the C-states info. */
 473         memset(pr->power.states, 0, sizeof(pr->power.states));
 474
 475         result = acpi_processor_get_power_info_cst(pr);
 476         if (result == -ENODEV)
 477                 result = acpi_processor_get_power_info_fadt(pr);
 478
 479         if (result)
 480                 return result;
 481
 482         acpi_processor_get_power_info_default(pr);
 483
 484         pr->power.count = acpi_processor_power_verify(pr);
 485
 486         /*
 487          * if one state of type C2 or C3 is available, mark this
 488          * CPU as being "idle manageable"
 489          */
 490         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 491                 if (pr->power.states[i].valid) {
 492                         pr->power.count = i;
 493                         pr->flags.power = 1;
 494                 }
 495         }
 496
 497         return 0;
 498 }
 499
 500 /**
 501  * acpi_idle_bm_check - checks if bus master activity was detected
 502  */
 503 static int acpi_idle_bm_check(void)
 504 {
 505         u32 bm_status = 0;
 506
 507         if (bm_check_disable)
 508                 return 0;
 509
 510         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 511         if (bm_status)
 512                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 513         /*
 514          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 515          * the true state of bus mastering activity; forcing us to
 516          * manually check the BMIDEA bit of each IDE channel.
 517          */
 518         else if (errata.piix4.bmisx) {
 519                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 520                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 521                         bm_status = 1;
 522         }
 523         return bm_status;
 524 }
 525
 526 static void wait_for_freeze(void)
 527 {
 528 #ifdef  CONFIG_X86
 529         /* No delay is needed if we are in guest */
 530         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 531                 return;
 532 #endif
 533         /* Dummy wait op - must do something useless after P_LVL2 read
 534            because chipsets cannot guarantee that STPCLK# signal
 535            gets asserted in time to freeze execution properly. */
 536         inl(acpi_gbl_FADT.xpm_timer_block.address);
 537 }
 538
 539 /**
 540  * acpi_idle_do_entry - enter idle state using the appropriate method
 541  * @cx: cstate data
 542  *
 543  * Caller disables interrupt before call and enables interrupt after return.
 544  */
 545 static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 546 {
 547         if (cx->entry_method == ACPI_CSTATE_FFH) {
 548                 /* Call into architectural FFH based C-state */
 549                 acpi_processor_ffh_cstate_enter(cx);
 550         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 551                 acpi_safe_halt();
 552         } else {
 553                 /* IO port based C-state */
 554                 inb(cx->address);
 555                 wait_for_freeze();
 556         }
 557 }
 558
 559 /**
 560  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 561  * @dev: the target CPU
 562  * @index: the index of suggested state
 563  */
 564 static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 565 {
 566         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 567
 568         if (cx->type == ACPI_STATE_C3)
 569                 ACPI_FLUSH_CPU_CACHE();
 570
 571         while (1) {
 572
 573                 if (cx->entry_method == ACPI_CSTATE_HALT)
 574                         safe_halt();
 575                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 576                         inb(cx->address);
 577                         wait_for_freeze();
 578                 } else
 579                         return -ENODEV;
 580
 581 #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
 582                 cond_wakeup_cpu0();
 583 #endif
 584         }
 585
 586         /* Never reached */
 587         return 0;
 588 }
 589
 590 static bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 591 {
 592         return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 593                 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 594 }
 595
 596 static int c3_cpu_count;
 597 static DEFINE_RAW_SPINLOCK(c3_lock);
 598
 599 /**
 600  * acpi_idle_enter_bm - enters C3 with proper BM handling
 601  * @drv: cpuidle driver
 602  * @pr: Target processor
 603  * @cx: Target state context
 604  * @index: index of target state
 605  */
 606 static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
 607                                struct acpi_processor *pr,
 608                                struct acpi_processor_cx *cx,
 609                                int index)
 610 {
 611         static struct acpi_processor_cx safe_cx = {
 612                 .entry_method = ACPI_CSTATE_HALT,
 613         };
 614
 615         /*
 616          * disable bus master
 617          * bm_check implies we need ARB_DIS
 618          * bm_control implies whether we can do ARB_DIS
 619          *
 620          * That leaves a case where bm_check is set and bm_control is not set.
 621          * In that case we cannot do much, we enter C3 without doing anything.
 622          */
 623         bool dis_bm = pr->flags.bm_control;
 624
 625         /* If we can skip BM, demote to a safe state. */
 626         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 627                 dis_bm = false;
 628                 index = drv->safe_state_index;
 629                 if (index >= 0) {
 630                         cx = this_cpu_read(acpi_cstate[index]);
 631                 } else {
 632                         cx = &safe_cx;
 633                         index = -EBUSY;
 634                 }
 635         }
 636
 637         if (dis_bm) {
 638                 raw_spin_lock(&c3_lock);
 639                 c3_cpu_count++;
 640                 /* Disable bus master arbitration when all CPUs are in C3 */
 641                 if (c3_cpu_count == num_online_cpus())
 642                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 643                 raw_spin_unlock(&c3_lock);
 644         }
 645
 646         rcu_idle_enter();
 647
 648         acpi_idle_do_entry(cx);
 649
 650         rcu_idle_exit();
 651
 652         /* Re-enable bus master arbitration */
 653         if (dis_bm) {
 654                 raw_spin_lock(&c3_lock);
 655                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 656                 c3_cpu_count--;
 657                 raw_spin_unlock(&c3_lock);
 658         }
 659
 660         return index;
 661 }
 662
 663 static int acpi_idle_enter(struct cpuidle_device *dev,
 664                            struct cpuidle_driver *drv, int index)
 665 {
 666         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 667         struct acpi_processor *pr;
 668
 669         pr = __this_cpu_read(processors);
 670         if (unlikely(!pr))
 671                 return -EINVAL;
 672
 673         if (cx->type != ACPI_STATE_C1) {
 674                 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 675                         return acpi_idle_enter_bm(drv, pr, cx, index);
 676
 677                 /* C2 to C1 demotion. */
 678                 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 679                         index = ACPI_IDLE_STATE_START;
 680                         cx = per_cpu(acpi_cstate[index], dev->cpu);
 681                 }
 682         }
 683
 684         if (cx->type == ACPI_STATE_C3)
 685                 ACPI_FLUSH_CPU_CACHE();
 686
 687         acpi_idle_do_entry(cx);
 688
 689         return index;
 690 }
 691
 692 static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 693                                   struct cpuidle_driver *drv, int index)
 694 {
 695         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 696
 697         if (cx->type == ACPI_STATE_C3) {
 698                 struct acpi_processor *pr = __this_cpu_read(processors);
 699
 700                 if (unlikely(!pr))
 701                         return 0;
 702
 703                 if (pr->flags.bm_check) {
 704                         u8 bm_sts_skip = cx->bm_sts_skip;
 705
 706                         /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 707                         cx->bm_sts_skip = 1;
 708                         acpi_idle_enter_bm(drv, pr, cx, index);
 709                         cx->bm_sts_skip = bm_sts_skip;
 710
 711                         return 0;
 712                 } else {
 713                         ACPI_FLUSH_CPU_CACHE();
 714                 }
 715         }
 716         acpi_idle_do_entry(cx);
 717
 718         return 0;
 719 }
 720
 721 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 722                                            struct cpuidle_device *dev)
 723 {
 724         int i, count = ACPI_IDLE_STATE_START;
 725         struct acpi_processor_cx *cx;
 726         struct cpuidle_state *state;
 727
 728         if (max_cstate == 0)
 729                 max_cstate = 1;
 730
 731         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 732                 state = &acpi_idle_driver.states[count];
 733                 cx = &pr->power.states[i];
 734
 735                 if (!cx->valid)
 736                         continue;
 737
 738                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
 739
 740                 if (lapic_timer_needs_broadcast(pr, cx))
 741                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 742
 743                 if (cx->type == ACPI_STATE_C3) {
 744                         state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 745                         if (pr->flags.bm_check)
 746                                 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 747                 }
 748
 749                 count++;
 750                 if (count == CPUIDLE_STATE_MAX)
 751                         break;
 752         }
 753
 754         if (!count)
 755                 return -EINVAL;
 756
 757         return 0;
 758 }
 759
 760 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 761 {
 762         int i, count;
 763         struct acpi_processor_cx *cx;
 764         struct cpuidle_state *state;
 765         struct cpuidle_driver *drv = &acpi_idle_driver;
 766
 767         if (max_cstate == 0)
 768                 max_cstate = 1;
 769
 770         if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 771                 cpuidle_poll_state_init(drv);
 772                 count = 1;
 773         } else {
 774                 count = 0;
 775         }
 776
 777         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 778                 cx = &pr->power.states[i];
 779
 780                 if (!cx->valid)
 781                         continue;
 782
 783                 state = &drv->states[count];
 784                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 785                 strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 786                 state->exit_latency = cx->latency;
 787                 state->target_residency = cx->latency * latency_factor;
 788                 state->enter = acpi_idle_enter;
 789
 790                 state->flags = 0;
 791                 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||
 792                     cx->type == ACPI_STATE_C3) {
 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                 d = acpi_fetch_acpi_dev(pr_ahandle);
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 }