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 <[email protected]>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[email protected]>
   7  *  Copyright (C) 2004, 2005 Dominik Brodowski <[email protected]>
   8  *  Copyright (C) 2004  Anil S Keshavamurthy <[email protected]>
   9  *                      - Added processor hotplug support
  10  *  Copyright (C) 2005  Venkatesh Pallipadi <[email protected]>
  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 <linux/perf_event.h>
  25 #include <acpi/processor.h>
  26 #include <linux/context_tracking.h>
  27
  28 /*
  29  * Include the apic definitions for x86 to have the APIC timer related defines
  30  * available also for UP (on SMP it gets magically included via linux/smp.h).
  31  * asm/acpi.h is not an option, as it would require more include magic. Also
  32  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  33  */
  34 #ifdef CONFIG_X86
  35 #include <asm/apic.h>
  36 #include <asm/cpu.h>
  37 #endif
  38
  39 #define ACPI_IDLE_STATE_START   (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  40
  41 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  42 module_param(max_cstate, uint, 0400);
  43 static bool nocst __read_mostly;
  44 module_param(nocst, bool, 0400);
  45 static bool bm_check_disable __read_mostly;
  46 module_param(bm_check_disable, bool, 0400);
  47
  48 static unsigned int latency_factor __read_mostly = 2;
  49 module_param(latency_factor, uint, 0644);
  50
  51 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  52
  53 struct cpuidle_driver acpi_idle_driver = {
  54         .name =         "acpi_idle",
  55         .owner =        THIS_MODULE,
  56 };
  57
  58 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  59 static
  60 DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  61
  62 static int disabled_by_idle_boot_param(void)
  63 {
  64         return boot_option_idle_override == IDLE_POLL ||
  65                 boot_option_idle_override == IDLE_HALT;
  66 }
  67
  68 /*
  69  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  70  * For now disable this. Probably a bug somewhere else.
  71  *
  72  * To skip this limit, boot/load with a large max_cstate limit.
  73  */
  74 static int set_max_cstate(const struct dmi_system_id *id)
  75 {
  76         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  77                 return 0;
  78
  79         pr_notice("%s detected - limiting to C%ld max_cstate."
  80                   " Override with \"processor.max_cstate=%d\"\n", id->ident,
  81                   (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  82
  83         max_cstate = (long)id->driver_data;
  84
  85         return 0;
  86 }
  87
  88 static const struct dmi_system_id processor_power_dmi_table[] = {
  89         { set_max_cstate, "Clevo 5600D", {
  90           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  91           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  92          (void *)2},
  93         { set_max_cstate, "Pavilion zv5000", {
  94           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  95           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
  96          (void *)1},
  97         { set_max_cstate, "Asus L8400B", {
  98           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  99           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
 100          (void *)1},
 101         {},
 102 };
 103
 104
 105 /*
 106  * Callers should disable interrupts before the call and enable
 107  * interrupts after return.
 108  */
 109 static void __cpuidle acpi_safe_halt(void)
 110 {
 111         if (!tif_need_resched()) {
 112                 raw_safe_halt();
 113                 raw_local_irq_disable();
 114         }
 115 }
 116
 117 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 118
 119 /*
 120  * Some BIOS implementations switch to C3 in the published C2 state.
 121  * This seems to be a common problem on AMD boxen, but other vendors
 122  * are affected too. We pick the most conservative approach: we assume
 123  * that the local APIC stops in both C2 and C3.
 124  */
 125 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 126                                    struct acpi_processor_cx *cx)
 127 {
 128         struct acpi_processor_power *pwr = &pr->power;
 129         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 130
 131         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 132                 return;
 133
 134         if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 135                 type = ACPI_STATE_C1;
 136
 137         /*
 138          * Check, if one of the previous states already marked the lapic
 139          * unstable
 140          */
 141         if (pwr->timer_broadcast_on_state < state)
 142                 return;
 143
 144         if (cx->type >= type)
 145                 pr->power.timer_broadcast_on_state = state;
 146 }
 147
 148 static void __lapic_timer_propagate_broadcast(void *arg)
 149 {
 150         struct acpi_processor *pr = arg;
 151
 152         if (pr->power.timer_broadcast_on_state < INT_MAX)
 153                 tick_broadcast_enable();
 154         else
 155                 tick_broadcast_disable();
 156 }
 157
 158 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 159 {
 160         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 161                                  (void *)pr, 1);
 162 }
 163
 164 /* Power(C) State timer broadcast control */
 165 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 166                                         struct acpi_processor_cx *cx)
 167 {
 168         return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 169 }
 170
 171 #else
 172
 173 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 174                                    struct acpi_processor_cx *cstate) { }
 175 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 176
 177 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 178                                         struct acpi_processor_cx *cx)
 179 {
 180         return false;
 181 }
 182
 183 #endif
 184
 185 #if defined(CONFIG_X86)
 186 static void tsc_check_state(int state)
 187 {
 188         switch (boot_cpu_data.x86_vendor) {
 189         case X86_VENDOR_HYGON:
 190         case X86_VENDOR_AMD:
 191         case X86_VENDOR_INTEL:
 192         case X86_VENDOR_CENTAUR:
 193         case X86_VENDOR_ZHAOXIN:
 194                 /*
 195                  * AMD Fam10h TSC will tick in all
 196                  * C/P/S0/S1 states when this bit is set.
 197                  */
 198                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 199                         return;
 200                 fallthrough;
 201         default:
 202                 /* TSC could halt in idle, so notify users */
 203                 if (state > ACPI_STATE_C1)
 204                         mark_tsc_unstable("TSC halts in idle");
 205         }
 206 }
 207 #else
 208 static void tsc_check_state(int state) { return; }
 209 #endif
 210
 211 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 212 {
 213
 214         if (!pr->pblk)
 215                 return -ENODEV;
 216
 217         /* if info is obtained from pblk/fadt, type equals state */
 218         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 219         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 220
 221 #ifndef CONFIG_HOTPLUG_CPU
 222         /*
 223          * Check for P_LVL2_UP flag before entering C2 and above on
 224          * an SMP system.
 225          */
 226         if ((num_online_cpus() > 1) &&
 227             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 228                 return -ENODEV;
 229 #endif
 230
 231         /* determine C2 and C3 address from pblk */
 232         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 233         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 234
 235         /* determine latencies from FADT */
 236         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 237         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 238
 239         /*
 240          * FADT specified C2 latency must be less than or equal to
 241          * 100 microseconds.
 242          */
 243         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 244                 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 245                                   acpi_gbl_FADT.c2_latency);
 246                 /* invalidate C2 */
 247                 pr->power.states[ACPI_STATE_C2].address = 0;
 248         }
 249
 250         /*
 251          * FADT supplied C3 latency must be less than or equal to
 252          * 1000 microseconds.
 253          */
 254         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 255                 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 256                                   acpi_gbl_FADT.c3_latency);
 257                 /* invalidate C3 */
 258                 pr->power.states[ACPI_STATE_C3].address = 0;
 259         }
 260
 261         acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 262                           pr->power.states[ACPI_STATE_C2].address,
 263                           pr->power.states[ACPI_STATE_C3].address);
 264
 265         snprintf(pr->power.states[ACPI_STATE_C2].desc,
 266                          ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 267                          pr->power.states[ACPI_STATE_C2].address);
 268         snprintf(pr->power.states[ACPI_STATE_C3].desc,
 269                          ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 270                          pr->power.states[ACPI_STATE_C3].address);
 271
 272         return 0;
 273 }
 274
 275 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 276 {
 277         if (!pr->power.states[ACPI_STATE_C1].valid) {
 278                 /* set the first C-State to C1 */
 279                 /* all processors need to support C1 */
 280                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 281                 pr->power.states[ACPI_STATE_C1].valid = 1;
 282                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 283
 284                 snprintf(pr->power.states[ACPI_STATE_C1].desc,
 285                          ACPI_CX_DESC_LEN, "ACPI HLT");
 286         }
 287         /* the C0 state only exists as a filler in our array */
 288         pr->power.states[ACPI_STATE_C0].valid = 1;
 289         return 0;
 290 }
 291
 292 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 293 {
 294         int ret;
 295
 296         if (nocst)
 297                 return -ENODEV;
 298
 299         ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 300         if (ret)
 301                 return ret;
 302
 303         if (!pr->power.count)
 304                 return -EFAULT;
 305
 306         pr->flags.has_cst = 1;
 307         return 0;
 308 }
 309
 310 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 311                                            struct acpi_processor_cx *cx)
 312 {
 313         static int bm_check_flag = -1;
 314         static int bm_control_flag = -1;
 315
 316
 317         if (!cx->address)
 318                 return;
 319
 320         /*
 321          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 322          * DMA transfers are used by any ISA device to avoid livelock.
 323          * Note that we could disable Type-F DMA (as recommended by
 324          * the erratum), but this is known to disrupt certain ISA
 325          * devices thus we take the conservative approach.
 326          */
 327         if (errata.piix4.fdma) {
 328                 acpi_handle_debug(pr->handle,
 329                                   "C3 not supported on PIIX4 with Type-F DMA\n");
 330                 return;
 331         }
 332
 333         /* All the logic here assumes flags.bm_check is same across all CPUs */
 334         if (bm_check_flag == -1) {
 335                 /* Determine whether bm_check is needed based on CPU  */
 336                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 337                 bm_check_flag = pr->flags.bm_check;
 338                 bm_control_flag = pr->flags.bm_control;
 339         } else {
 340                 pr->flags.bm_check = bm_check_flag;
 341                 pr->flags.bm_control = bm_control_flag;
 342         }
 343
 344         if (pr->flags.bm_check) {
 345                 if (!pr->flags.bm_control) {
 346                         if (pr->flags.has_cst != 1) {
 347                                 /* bus mastering control is necessary */
 348                                 acpi_handle_debug(pr->handle,
 349                                                   "C3 support requires BM control\n");
 350                                 return;
 351                         } else {
 352                                 /* Here we enter C3 without bus mastering */
 353                                 acpi_handle_debug(pr->handle,
 354                                                   "C3 support without BM control\n");
 355                         }
 356                 }
 357         } else {
 358                 /*
 359                  * WBINVD should be set in fadt, for C3 state to be
 360                  * supported on when bm_check is not required.
 361                  */
 362                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 363                         acpi_handle_debug(pr->handle,
 364                                           "Cache invalidation should work properly"
 365                                           " for C3 to be enabled on SMP systems\n");
 366                         return;
 367                 }
 368         }
 369
 370         /*
 371          * Otherwise we've met all of our C3 requirements.
 372          * Normalize the C3 latency to expidite policy.  Enable
 373          * checking of bus mastering status (bm_check) so we can
 374          * use this in our C3 policy
 375          */
 376         cx->valid = 1;
 377
 378         /*
 379          * On older chipsets, BM_RLD needs to be set
 380          * in order for Bus Master activity to wake the
 381          * system from C3.  Newer chipsets handle DMA
 382          * during C3 automatically and BM_RLD is a NOP.
 383          * In either case, the proper way to
 384          * handle BM_RLD is to set it and leave it set.
 385          */
 386         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 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 __cpuidle void io_idle(unsigned long addr)
 527 {
 528         /* IO port based C-state */
 529         inb(addr);
 530
 531 #ifdef  CONFIG_X86
 532         /* No delay is needed if we are in guest */
 533         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 534                 return;
 535         /*
 536          * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
 537          * not this code.  Assume that any Intel systems using this
 538          * are ancient and may need the dummy wait.  This also assumes
 539          * that the motivating chipset issue was Intel-only.
 540          */
 541         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 542                 return;
 543 #endif
 544         /*
 545          * Dummy wait op - must do something useless after P_LVL2 read
 546          * because chipsets cannot guarantee that STPCLK# signal gets
 547          * asserted in time to freeze execution properly
 548          *
 549          * This workaround has been in place since the original ACPI
 550          * implementation was merged, circa 2002.
 551          *
 552          * If a profile is pointing to this instruction, please first
 553          * consider moving your system to a more modern idle
 554          * mechanism.
 555          */
 556         inl(acpi_gbl_FADT.xpm_timer_block.address);
 557 }
 558
 559 /**
 560  * acpi_idle_do_entry - enter idle state using the appropriate method
 561  * @cx: cstate data
 562  *
 563  * Caller disables interrupt before call and enables interrupt after return.
 564  */
 565 static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 566 {
 567         perf_lopwr_cb(true);
 568
 569         if (cx->entry_method == ACPI_CSTATE_FFH) {
 570                 /* Call into architectural FFH based C-state */
 571                 acpi_processor_ffh_cstate_enter(cx);
 572         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 573                 acpi_safe_halt();
 574         } else {
 575                 io_idle(cx->address);
 576         }
 577
 578         perf_lopwr_cb(false);
 579 }
 580
 581 /**
 582  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 583  * @dev: the target CPU
 584  * @index: the index of suggested state
 585  */
 586 static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 587 {
 588         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 589
 590         ACPI_FLUSH_CPU_CACHE();
 591
 592         while (1) {
 593
 594                 if (cx->entry_method == ACPI_CSTATE_HALT)
 595                         safe_halt();
 596                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 597                         io_idle(cx->address);
 598                 } else
 599                         return -ENODEV;
 600
 601 #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
 602                 cond_wakeup_cpu0();
 603 #endif
 604         }
 605
 606         /* Never reached */
 607         return 0;
 608 }
 609
 610 static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 611 {
 612         return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 613                 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 614 }
 615
 616 static int c3_cpu_count;
 617 static DEFINE_RAW_SPINLOCK(c3_lock);
 618
 619 /**
 620  * acpi_idle_enter_bm - enters C3 with proper BM handling
 621  * @drv: cpuidle driver
 622  * @pr: Target processor
 623  * @cx: Target state context
 624  * @index: index of target state
 625  */
 626 static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
 627                                struct acpi_processor *pr,
 628                                struct acpi_processor_cx *cx,
 629                                int index)
 630 {
 631         static struct acpi_processor_cx safe_cx = {
 632                 .entry_method = ACPI_CSTATE_HALT,
 633         };
 634
 635         /*
 636          * disable bus master
 637          * bm_check implies we need ARB_DIS
 638          * bm_control implies whether we can do ARB_DIS
 639          *
 640          * That leaves a case where bm_check is set and bm_control is not set.
 641          * In that case we cannot do much, we enter C3 without doing anything.
 642          */
 643         bool dis_bm = pr->flags.bm_control;
 644
 645         instrumentation_begin();
 646
 647         /* If we can skip BM, demote to a safe state. */
 648         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 649                 dis_bm = false;
 650                 index = drv->safe_state_index;
 651                 if (index >= 0) {
 652                         cx = this_cpu_read(acpi_cstate[index]);
 653                 } else {
 654                         cx = &safe_cx;
 655                         index = -EBUSY;
 656                 }
 657         }
 658
 659         if (dis_bm) {
 660                 raw_spin_lock(&c3_lock);
 661                 c3_cpu_count++;
 662                 /* Disable bus master arbitration when all CPUs are in C3 */
 663                 if (c3_cpu_count == num_online_cpus())
 664                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 665                 raw_spin_unlock(&c3_lock);
 666         }
 667
 668         ct_cpuidle_enter();
 669
 670         acpi_idle_do_entry(cx);
 671
 672         ct_cpuidle_exit();
 673
 674         /* Re-enable bus master arbitration */
 675         if (dis_bm) {
 676                 raw_spin_lock(&c3_lock);
 677                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 678                 c3_cpu_count--;
 679                 raw_spin_unlock(&c3_lock);
 680         }
 681
 682         instrumentation_end();
 683
 684         return index;
 685 }
 686
 687 static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
 688                            struct cpuidle_driver *drv, int index)
 689 {
 690         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 691         struct acpi_processor *pr;
 692
 693         pr = __this_cpu_read(processors);
 694         if (unlikely(!pr))
 695                 return -EINVAL;
 696
 697         if (cx->type != ACPI_STATE_C1) {
 698                 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 699                         return acpi_idle_enter_bm(drv, pr, cx, index);
 700
 701                 /* C2 to C1 demotion. */
 702                 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 703                         index = ACPI_IDLE_STATE_START;
 704                         cx = per_cpu(acpi_cstate[index], dev->cpu);
 705                 }
 706         }
 707
 708         if (cx->type == ACPI_STATE_C3)
 709                 ACPI_FLUSH_CPU_CACHE();
 710
 711         acpi_idle_do_entry(cx);
 712
 713         return index;
 714 }
 715
 716 static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 717                                   struct cpuidle_driver *drv, int index)
 718 {
 719         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 720
 721         if (cx->type == ACPI_STATE_C3) {
 722                 struct acpi_processor *pr = __this_cpu_read(processors);
 723
 724                 if (unlikely(!pr))
 725                         return 0;
 726
 727                 if (pr->flags.bm_check) {
 728                         u8 bm_sts_skip = cx->bm_sts_skip;
 729
 730                         /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 731                         cx->bm_sts_skip = 1;
 732                         acpi_idle_enter_bm(drv, pr, cx, index);
 733                         cx->bm_sts_skip = bm_sts_skip;
 734
 735                         return 0;
 736                 } else {
 737                         ACPI_FLUSH_CPU_CACHE();
 738                 }
 739         }
 740         acpi_idle_do_entry(cx);
 741
 742         return 0;
 743 }
 744
 745 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 746                                            struct cpuidle_device *dev)
 747 {
 748         int i, count = ACPI_IDLE_STATE_START;
 749         struct acpi_processor_cx *cx;
 750         struct cpuidle_state *state;
 751
 752         if (max_cstate == 0)
 753                 max_cstate = 1;
 754
 755         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 756                 state = &acpi_idle_driver.states[count];
 757                 cx = &pr->power.states[i];
 758
 759                 if (!cx->valid)
 760                         continue;
 761
 762                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
 763
 764                 if (lapic_timer_needs_broadcast(pr, cx))
 765                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 766
 767                 if (cx->type == ACPI_STATE_C3) {
 768                         state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 769                         if (pr->flags.bm_check)
 770                                 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 771                 }
 772
 773                 count++;
 774                 if (count == CPUIDLE_STATE_MAX)
 775                         break;
 776         }
 777
 778         if (!count)
 779                 return -EINVAL;
 780
 781         return 0;
 782 }
 783
 784 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 785 {
 786         int i, count;
 787         struct acpi_processor_cx *cx;
 788         struct cpuidle_state *state;
 789         struct cpuidle_driver *drv = &acpi_idle_driver;
 790
 791         if (max_cstate == 0)
 792                 max_cstate = 1;
 793
 794         if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 795                 cpuidle_poll_state_init(drv);
 796                 count = 1;
 797         } else {
 798                 count = 0;
 799         }
 800
 801         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 802                 cx = &pr->power.states[i];
 803
 804                 if (!cx->valid)
 805                         continue;
 806
 807                 state = &drv->states[count];
 808                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 809                 strscpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 810                 state->exit_latency = cx->latency;
 811                 state->target_residency = cx->latency * latency_factor;
 812                 state->enter = acpi_idle_enter;
 813
 814                 state->flags = 0;
 815                 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||
 816                     cx->type == ACPI_STATE_C3) {
 817                         state->enter_dead = acpi_idle_play_dead;
 818                         if (cx->type != ACPI_STATE_C3)
 819                                 drv->safe_state_index = count;
 820                 }
 821                 /*
 822                  * Halt-induced C1 is not good for ->enter_s2idle, because it
 823                  * re-enables interrupts on exit.  Moreover, C1 is generally not
 824                  * particularly interesting from the suspend-to-idle angle, so
 825                  * avoid C1 and the situations in which we may need to fall back
 826                  * to it altogether.
 827                  */
 828                 if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
 829                         state->enter_s2idle = acpi_idle_enter_s2idle;
 830
 831                 count++;
 832                 if (count == CPUIDLE_STATE_MAX)
 833                         break;
 834         }
 835
 836         drv->state_count = count;
 837
 838         if (!count)
 839                 return -EINVAL;
 840
 841         return 0;
 842 }
 843
 844 static inline void acpi_processor_cstate_first_run_checks(void)
 845 {
 846         static int first_run;
 847
 848         if (first_run)
 849                 return;
 850         dmi_check_system(processor_power_dmi_table);
 851         max_cstate = acpi_processor_cstate_check(max_cstate);
 852         if (max_cstate < ACPI_C_STATES_MAX)
 853                 pr_notice("processor limited to max C-state %d\n", max_cstate);
 854
 855         first_run++;
 856
 857         if (nocst)
 858                 return;
 859
 860         acpi_processor_claim_cst_control();
 861 }
 862 #else
 863
 864 static inline int disabled_by_idle_boot_param(void) { return 0; }
 865 static inline void acpi_processor_cstate_first_run_checks(void) { }
 866 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 867 {
 868         return -ENODEV;
 869 }
 870
 871 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 872                                            struct cpuidle_device *dev)
 873 {
 874         return -EINVAL;
 875 }
 876
 877 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 878 {
 879         return -EINVAL;
 880 }
 881
 882 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 883
 884 struct acpi_lpi_states_array {
 885         unsigned int size;
 886         unsigned int composite_states_size;
 887         struct acpi_lpi_state *entries;
 888         struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
 889 };
 890
 891 static int obj_get_integer(union acpi_object *obj, u32 *value)
 892 {
 893         if (obj->type != ACPI_TYPE_INTEGER)
 894                 return -EINVAL;
 895
 896         *value = obj->integer.value;
 897         return 0;
 898 }
 899
 900 static int acpi_processor_evaluate_lpi(acpi_handle handle,
 901                                        struct acpi_lpi_states_array *info)
 902 {
 903         acpi_status status;
 904         int ret = 0;
 905         int pkg_count, state_idx = 1, loop;
 906         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 907         union acpi_object *lpi_data;
 908         struct acpi_lpi_state *lpi_state;
 909
 910         status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
 911         if (ACPI_FAILURE(status)) {
 912                 acpi_handle_debug(handle, "No _LPI, giving up\n");
 913                 return -ENODEV;
 914         }
 915
 916         lpi_data = buffer.pointer;
 917
 918         /* There must be at least 4 elements = 3 elements + 1 package */
 919         if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
 920             lpi_data->package.count < 4) {
 921                 pr_debug("not enough elements in _LPI\n");
 922                 ret = -ENODATA;
 923                 goto end;
 924         }
 925
 926         pkg_count = lpi_data->package.elements[2].integer.value;
 927
 928         /* Validate number of power states. */
 929         if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
 930                 pr_debug("count given by _LPI is not valid\n");
 931                 ret = -ENODATA;
 932                 goto end;
 933         }
 934
 935         lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
 936         if (!lpi_state) {
 937                 ret = -ENOMEM;
 938                 goto end;
 939         }
 940
 941         info->size = pkg_count;
 942         info->entries = lpi_state;
 943
 944         /* LPI States start at index 3 */
 945         for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
 946                 union acpi_object *element, *pkg_elem, *obj;
 947
 948                 element = &lpi_data->package.elements[loop];
 949                 if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
 950                         continue;
 951
 952                 pkg_elem = element->package.elements;
 953
 954                 obj = pkg_elem + 6;
 955                 if (obj->type == ACPI_TYPE_BUFFER) {
 956                         struct acpi_power_register *reg;
 957
 958                         reg = (struct acpi_power_register *)obj->buffer.pointer;
 959                         if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 960                             reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
 961                                 continue;
 962
 963                         lpi_state->address = reg->address;
 964                         lpi_state->entry_method =
 965                                 reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
 966                                 ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
 967                 } else if (obj->type == ACPI_TYPE_INTEGER) {
 968                         lpi_state->entry_method = ACPI_CSTATE_INTEGER;
 969                         lpi_state->address = obj->integer.value;
 970                 } else {
 971                         continue;
 972                 }
 973
 974                 /* elements[7,8] skipped for now i.e. Residency/Usage counter*/
 975
 976                 obj = pkg_elem + 9;
 977                 if (obj->type == ACPI_TYPE_STRING)
 978                         strscpy(lpi_state->desc, obj->string.pointer,
 979                                 ACPI_CX_DESC_LEN);
 980
 981                 lpi_state->index = state_idx;
 982                 if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
 983                         pr_debug("No min. residency found, assuming 10 us\n");
 984                         lpi_state->min_residency = 10;
 985                 }
 986
 987                 if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
 988                         pr_debug("No wakeup residency found, assuming 10 us\n");
 989                         lpi_state->wake_latency = 10;
 990                 }
 991
 992                 if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
 993                         lpi_state->flags = 0;
 994
 995                 if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
 996                         lpi_state->arch_flags = 0;
 997
 998                 if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
 999                         lpi_state->res_cnt_freq = 1;
1000
1001                 if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
1002                         lpi_state->enable_parent_state = 0;
1003         }
1004
1005         acpi_handle_debug(handle, "Found %d power states\n", state_idx);
1006 end:
1007         kfree(buffer.pointer);
1008         return ret;
1009 }
1010
1011 /*
1012  * flat_state_cnt - the number of composite LPI states after the process of flattening
1013  */
1014 static int flat_state_cnt;
1015
1016 /**
1017  * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
1018  *
1019  * @local: local LPI state
1020  * @parent: parent LPI state
1021  * @result: composite LPI state
1022  */
1023 static bool combine_lpi_states(struct acpi_lpi_state *local,
1024                                struct acpi_lpi_state *parent,
1025                                struct acpi_lpi_state *result)
1026 {
1027         if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1028                 if (!parent->address) /* 0 means autopromotable */
1029                         return false;
1030                 result->address = local->address + parent->address;
1031         } else {
1032                 result->address = parent->address;
1033         }
1034
1035         result->min_residency = max(local->min_residency, parent->min_residency);
1036         result->wake_latency = local->wake_latency + parent->wake_latency;
1037         result->enable_parent_state = parent->enable_parent_state;
1038         result->entry_method = local->entry_method;
1039
1040         result->flags = parent->flags;
1041         result->arch_flags = parent->arch_flags;
1042         result->index = parent->index;
1043
1044         strscpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
1045         strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
1046         strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
1047         return true;
1048 }
1049
1050 #define ACPI_LPI_STATE_FLAGS_ENABLED                    BIT(0)
1051
1052 static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1053                                   struct acpi_lpi_state *t)
1054 {
1055         curr_level->composite_states[curr_level->composite_states_size++] = t;
1056 }
1057
1058 static int flatten_lpi_states(struct acpi_processor *pr,
1059                               struct acpi_lpi_states_array *curr_level,
1060                               struct acpi_lpi_states_array *prev_level)
1061 {
1062         int i, j, state_count = curr_level->size;
1063         struct acpi_lpi_state *p, *t = curr_level->entries;
1064
1065         curr_level->composite_states_size = 0;
1066         for (j = 0; j < state_count; j++, t++) {
1067                 struct acpi_lpi_state *flpi;
1068
1069                 if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1070                         continue;
1071
1072                 if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1073                         pr_warn("Limiting number of LPI states to max (%d)\n",
1074                                 ACPI_PROCESSOR_MAX_POWER);
1075                         pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1076                         break;
1077                 }
1078
1079                 flpi = &pr->power.lpi_states[flat_state_cnt];
1080
1081                 if (!prev_level) { /* leaf/processor node */
1082                         memcpy(flpi, t, sizeof(*t));
1083                         stash_composite_state(curr_level, flpi);
1084                         flat_state_cnt++;
1085                         continue;
1086                 }
1087
1088                 for (i = 0; i < prev_level->composite_states_size; i++) {
1089                         p = prev_level->composite_states[i];
1090                         if (t->index <= p->enable_parent_state &&
1091                             combine_lpi_states(p, t, flpi)) {
1092                                 stash_composite_state(curr_level, flpi);
1093                                 flat_state_cnt++;
1094                                 flpi++;
1095                         }
1096                 }
1097         }
1098
1099         kfree(curr_level->entries);
1100         return 0;
1101 }
1102
1103 int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1104 {
1105         return -EOPNOTSUPP;
1106 }
1107
1108 static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1109 {
1110         int ret, i;
1111         acpi_status status;
1112         acpi_handle handle = pr->handle, pr_ahandle;
1113         struct acpi_device *d = NULL;
1114         struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1115
1116         /* make sure our architecture has support */
1117         ret = acpi_processor_ffh_lpi_probe(pr->id);
1118         if (ret == -EOPNOTSUPP)
1119                 return ret;
1120
1121         if (!osc_pc_lpi_support_confirmed)
1122                 return -EOPNOTSUPP;
1123
1124         if (!acpi_has_method(handle, "_LPI"))
1125                 return -EINVAL;
1126
1127         flat_state_cnt = 0;
1128         prev = &info[0];
1129         curr = &info[1];
1130         handle = pr->handle;
1131         ret = acpi_processor_evaluate_lpi(handle, prev);
1132         if (ret)
1133                 return ret;
1134         flatten_lpi_states(pr, prev, NULL);
1135
1136         status = acpi_get_parent(handle, &pr_ahandle);
1137         while (ACPI_SUCCESS(status)) {
1138                 d = acpi_fetch_acpi_dev(pr_ahandle);
1139                 if (!d)
1140                         break;
1141
1142                 handle = pr_ahandle;
1143
1144                 if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
1145                         break;
1146
1147                 /* can be optional ? */
1148                 if (!acpi_has_method(handle, "_LPI"))
1149                         break;
1150
1151                 ret = acpi_processor_evaluate_lpi(handle, curr);
1152                 if (ret)
1153                         break;
1154
1155                 /* flatten all the LPI states in this level of hierarchy */
1156                 flatten_lpi_states(pr, curr, prev);
1157
1158                 tmp = prev, prev = curr, curr = tmp;
1159
1160                 status = acpi_get_parent(handle, &pr_ahandle);
1161         }
1162
1163         pr->power.count = flat_state_cnt;
1164         /* reset the index after flattening */
1165         for (i = 0; i < pr->power.count; i++)
1166                 pr->power.lpi_states[i].index = i;
1167
1168         /* Tell driver that _LPI is supported. */
1169         pr->flags.has_lpi = 1;
1170         pr->flags.power = 1;
1171
1172         return 0;
1173 }
1174
1175 int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1176 {
1177         return -ENODEV;
1178 }
1179
1180 /**
1181  * acpi_idle_lpi_enter - enters an ACPI any LPI state
1182  * @dev: the target CPU
1183  * @drv: cpuidle driver containing cpuidle state info
1184  * @index: index of target state
1185  *
1186  * Return: 0 for success or negative value for error
1187  */
1188 static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1189                                struct cpuidle_driver *drv, int index)
1190 {
1191         struct acpi_processor *pr;
1192         struct acpi_lpi_state *lpi;
1193
1194         pr = __this_cpu_read(processors);
1195
1196         if (unlikely(!pr))
1197                 return -EINVAL;
1198
1199         lpi = &pr->power.lpi_states[index];
1200         if (lpi->entry_method == ACPI_CSTATE_FFH)
1201                 return acpi_processor_ffh_lpi_enter(lpi);
1202
1203         return -EINVAL;
1204 }
1205
1206 static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1207 {
1208         int i;
1209         struct acpi_lpi_state *lpi;
1210         struct cpuidle_state *state;
1211         struct cpuidle_driver *drv = &acpi_idle_driver;
1212
1213         if (!pr->flags.has_lpi)
1214                 return -EOPNOTSUPP;
1215
1216         for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1217                 lpi = &pr->power.lpi_states[i];
1218
1219                 state = &drv->states[i];
1220                 snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
1221                 strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
1222                 state->exit_latency = lpi->wake_latency;
1223                 state->target_residency = lpi->min_residency;
1224                 if (lpi->arch_flags)
1225                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
1226                 if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
1227                         state->flags |= CPUIDLE_FLAG_RCU_IDLE;
1228                 state->enter = acpi_idle_lpi_enter;
1229                 drv->safe_state_index = i;
1230         }
1231
1232         drv->state_count = i;
1233
1234         return 0;
1235 }
1236
1237 /**
1238  * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1239  * global state data i.e. idle routines
1240  *
1241  * @pr: the ACPI processor
1242  */
1243 static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1244 {
1245         int i;
1246         struct cpuidle_driver *drv = &acpi_idle_driver;
1247
1248         if (!pr->flags.power_setup_done || !pr->flags.power)
1249                 return -EINVAL;
1250
1251         drv->safe_state_index = -1;
1252         for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1253                 drv->states[i].name[0] = '\0';
1254                 drv->states[i].desc[0] = '\0';
1255         }
1256
1257         if (pr->flags.has_lpi)
1258                 return acpi_processor_setup_lpi_states(pr);
1259
1260         return acpi_processor_setup_cstates(pr);
1261 }
1262
1263 /**
1264  * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1265  * device i.e. per-cpu data
1266  *
1267  * @pr: the ACPI processor
1268  * @dev : the cpuidle device
1269  */
1270 static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1271                                             struct cpuidle_device *dev)
1272 {
1273         if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1274                 return -EINVAL;
1275
1276         dev->cpu = pr->id;
1277         if (pr->flags.has_lpi)
1278                 return acpi_processor_ffh_lpi_probe(pr->id);
1279
1280         return acpi_processor_setup_cpuidle_cx(pr, dev);
1281 }
1282
1283 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1284 {
1285         int ret;
1286
1287         ret = acpi_processor_get_lpi_info(pr);
1288         if (ret)
1289                 ret = acpi_processor_get_cstate_info(pr);
1290
1291         return ret;
1292 }
1293
1294 int acpi_processor_hotplug(struct acpi_processor *pr)
1295 {
1296         int ret = 0;
1297         struct cpuidle_device *dev;
1298
1299         if (disabled_by_idle_boot_param())
1300                 return 0;
1301
1302         if (!pr->flags.power_setup_done)
1303                 return -ENODEV;
1304
1305         dev = per_cpu(acpi_cpuidle_device, pr->id);
1306         cpuidle_pause_and_lock();
1307         cpuidle_disable_device(dev);
1308         ret = acpi_processor_get_power_info(pr);
1309         if (!ret && pr->flags.power) {
1310                 acpi_processor_setup_cpuidle_dev(pr, dev);
1311                 ret = cpuidle_enable_device(dev);
1312         }
1313         cpuidle_resume_and_unlock();
1314
1315         return ret;
1316 }
1317
1318 int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1319 {
1320         int cpu;
1321         struct acpi_processor *_pr;
1322         struct cpuidle_device *dev;
1323
1324         if (disabled_by_idle_boot_param())
1325                 return 0;
1326
1327         if (!pr->flags.power_setup_done)
1328                 return -ENODEV;
1329
1330         /*
1331          * FIXME:  Design the ACPI notification to make it once per
1332          * system instead of once per-cpu.  This condition is a hack
1333          * to make the code that updates C-States be called once.
1334          */
1335
1336         if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1337
1338                 /* Protect against cpu-hotplug */
1339                 cpus_read_lock();
1340                 cpuidle_pause_and_lock();
1341
1342                 /* Disable all cpuidle devices */
1343                 for_each_online_cpu(cpu) {
1344                         _pr = per_cpu(processors, cpu);
1345                         if (!_pr || !_pr->flags.power_setup_done)
1346                                 continue;
1347                         dev = per_cpu(acpi_cpuidle_device, cpu);
1348                         cpuidle_disable_device(dev);
1349                 }
1350
1351                 /* Populate Updated C-state information */
1352                 acpi_processor_get_power_info(pr);
1353                 acpi_processor_setup_cpuidle_states(pr);
1354
1355                 /* Enable all cpuidle devices */
1356                 for_each_online_cpu(cpu) {
1357                         _pr = per_cpu(processors, cpu);
1358                         if (!_pr || !_pr->flags.power_setup_done)
1359                                 continue;
1360                         acpi_processor_get_power_info(_pr);
1361                         if (_pr->flags.power) {
1362                                 dev = per_cpu(acpi_cpuidle_device, cpu);
1363                                 acpi_processor_setup_cpuidle_dev(_pr, dev);
1364                                 cpuidle_enable_device(dev);
1365                         }
1366                 }
1367                 cpuidle_resume_and_unlock();
1368                 cpus_read_unlock();
1369         }
1370
1371         return 0;
1372 }
1373
1374 static int acpi_processor_registered;
1375
1376 int acpi_processor_power_init(struct acpi_processor *pr)
1377 {
1378         int retval;
1379         struct cpuidle_device *dev;
1380
1381         if (disabled_by_idle_boot_param())
1382                 return 0;
1383
1384         acpi_processor_cstate_first_run_checks();
1385
1386         if (!acpi_processor_get_power_info(pr))
1387                 pr->flags.power_setup_done = 1;
1388
1389         /*
1390          * Install the idle handler if processor power management is supported.
1391          * Note that we use previously set idle handler will be used on
1392          * platforms that only support C1.
1393          */
1394         if (pr->flags.power) {
1395                 /* Register acpi_idle_driver if not already registered */
1396                 if (!acpi_processor_registered) {
1397                         acpi_processor_setup_cpuidle_states(pr);
1398                         retval = cpuidle_register_driver(&acpi_idle_driver);
1399                         if (retval)
1400                                 return retval;
1401                         pr_debug("%s registered with cpuidle\n",
1402                                  acpi_idle_driver.name);
1403                 }
1404
1405                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1406                 if (!dev)
1407                         return -ENOMEM;
1408                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1409
1410                 acpi_processor_setup_cpuidle_dev(pr, dev);
1411
1412                 /* Register per-cpu cpuidle_device. Cpuidle driver
1413                  * must already be registered before registering device
1414                  */
1415                 retval = cpuidle_register_device(dev);
1416                 if (retval) {
1417                         if (acpi_processor_registered == 0)
1418                                 cpuidle_unregister_driver(&acpi_idle_driver);
1419                         return retval;
1420                 }
1421                 acpi_processor_registered++;
1422         }
1423         return 0;
1424 }
1425
1426 int acpi_processor_power_exit(struct acpi_processor *pr)
1427 {
1428         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1429
1430         if (disabled_by_idle_boot_param())
1431                 return 0;
1432
1433         if (pr->flags.power) {
1434                 cpuidle_unregister_device(dev);
1435                 acpi_processor_registered--;
1436                 if (acpi_processor_registered == 0)
1437                         cpuidle_unregister_driver(&acpi_idle_driver);
1438         }
1439
1440         pr->flags.power_setup_done = 0;
1441         return 0;
1442 }