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/tick.h>
  20 #include <linux/cpuidle.h>
  21 #include <linux/cpu.h>
  22 #include <linux/minmax.h>
  23 #include <linux/perf_event.h>
  24 #include <acpi/processor.h>
  25 #include <linux/context_tracking.h>
  26
  27 #include "internal.h"
  28
  29 /*
  30  * Include the apic definitions for x86 to have the APIC timer related defines
  31  * available also for UP (on SMP it gets magically included via linux/smp.h).
  32  * asm/acpi.h is not an option, as it would require more include magic. Also
  33  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  34  */
  35 #ifdef CONFIG_X86
  36 #include <asm/apic.h>
  37 #include <asm/cpu.h>
  38 #endif
  39
  40 #define ACPI_IDLE_STATE_START   (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  41
  42 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  43 module_param(max_cstate, uint, 0400);
  44 static bool nocst __read_mostly;
  45 module_param(nocst, bool, 0400);
  46 static bool bm_check_disable __read_mostly;
  47 module_param(bm_check_disable, bool, 0400);
  48
  49 static unsigned int latency_factor __read_mostly = 2;
  50 module_param(latency_factor, uint, 0644);
  51
  52 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  53
  54 struct cpuidle_driver acpi_idle_driver = {
  55         .name =         "acpi_idle",
  56         .owner =        THIS_MODULE,
  57 };
  58
  59 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  60 void acpi_idle_rescan_dead_smt_siblings(void)
  61 {
  62         if (cpuidle_get_driver() == &acpi_idle_driver)
  63                 arch_cpu_rescan_dead_smt_siblings();
  64 }
  65
  66 static
  67 DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  68
  69 static int disabled_by_idle_boot_param(void)
  70 {
  71         return boot_option_idle_override == IDLE_POLL ||
  72                 boot_option_idle_override == IDLE_HALT;
  73 }
  74
  75 /*
  76  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  77  * For now disable this. Probably a bug somewhere else.
  78  *
  79  * To skip this limit, boot/load with a large max_cstate limit.
  80  */
  81 static int set_max_cstate(const struct dmi_system_id *id)
  82 {
  83         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  84                 return 0;
  85
  86         pr_notice("%s detected - limiting to C%ld max_cstate."
  87                   " Override with \"processor.max_cstate=%d\"\n", id->ident,
  88                   (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  89
  90         max_cstate = (long)id->driver_data;
  91
  92         return 0;
  93 }
  94
  95 static const struct dmi_system_id processor_power_dmi_table[] = {
  96         { set_max_cstate, "Clevo 5600D", {
  97           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  98           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  99          (void *)2},
 100         { set_max_cstate, "Pavilion zv5000", {
 101           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 102           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
 103          (void *)1},
 104         { set_max_cstate, "Asus L8400B", {
 105           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 106           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
 107          (void *)1},
 108         {},
 109 };
 110
 111
 112 /*
 113  * Callers should disable interrupts before the call and enable
 114  * interrupts after return.
 115  */
 116 static void __cpuidle acpi_safe_halt(void)
 117 {
 118         if (!tif_need_resched()) {
 119                 raw_safe_halt();
 120                 raw_local_irq_disable();
 121         }
 122 }
 123
 124 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 125
 126 /*
 127  * Some BIOS implementations switch to C3 in the published C2 state.
 128  * This seems to be a common problem on AMD boxen, but other vendors
 129  * are affected too. We pick the most conservative approach: we assume
 130  * that the local APIC stops in both C2 and C3.
 131  */
 132 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 133                                    struct acpi_processor_cx *cx)
 134 {
 135         struct acpi_processor_power *pwr = &pr->power;
 136         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 137
 138         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 139                 return;
 140
 141         if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 142                 type = ACPI_STATE_C1;
 143
 144         /*
 145          * Check, if one of the previous states already marked the lapic
 146          * unstable
 147          */
 148         if (pwr->timer_broadcast_on_state < state)
 149                 return;
 150
 151         if (cx->type >= type)
 152                 pr->power.timer_broadcast_on_state = state;
 153 }
 154
 155 static void __lapic_timer_propagate_broadcast(void *arg)
 156 {
 157         struct acpi_processor *pr = arg;
 158
 159         if (pr->power.timer_broadcast_on_state < INT_MAX)
 160                 tick_broadcast_enable();
 161         else
 162                 tick_broadcast_disable();
 163 }
 164
 165 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 166 {
 167         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 168                                  (void *)pr, 1);
 169 }
 170
 171 /* Power(C) State timer broadcast control */
 172 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 173                                         struct acpi_processor_cx *cx)
 174 {
 175         return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 176 }
 177
 178 #else
 179
 180 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 181                                    struct acpi_processor_cx *cstate) { }
 182 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 183
 184 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 185                                         struct acpi_processor_cx *cx)
 186 {
 187         return false;
 188 }
 189
 190 #endif
 191
 192 #if defined(CONFIG_X86)
 193 static void tsc_check_state(int state)
 194 {
 195         switch (boot_cpu_data.x86_vendor) {
 196         case X86_VENDOR_HYGON:
 197         case X86_VENDOR_AMD:
 198         case X86_VENDOR_INTEL:
 199         case X86_VENDOR_CENTAUR:
 200         case X86_VENDOR_ZHAOXIN:
 201                 /*
 202                  * AMD Fam10h TSC will tick in all
 203                  * C/P/S0/S1 states when this bit is set.
 204                  */
 205                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 206                         return;
 207                 fallthrough;
 208         default:
 209                 /* TSC could halt in idle, so notify users */
 210                 if (state > ACPI_STATE_C1)
 211                         mark_tsc_unstable("TSC halts in idle");
 212         }
 213 }
 214 #else
 215 static void tsc_check_state(int state) { return; }
 216 #endif
 217
 218 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 219 {
 220
 221         if (!pr->pblk)
 222                 return -ENODEV;
 223
 224         /* if info is obtained from pblk/fadt, type equals state */
 225         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 226         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 227
 228 #ifndef CONFIG_HOTPLUG_CPU
 229         /*
 230          * Check for P_LVL2_UP flag before entering C2 and above on
 231          * an SMP system.
 232          */
 233         if ((num_online_cpus() > 1) &&
 234             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 235                 return -ENODEV;
 236 #endif
 237
 238         /* determine C2 and C3 address from pblk */
 239         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 240         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 241
 242         /* determine latencies from FADT */
 243         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 244         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 245
 246         /*
 247          * FADT specified C2 latency must be less than or equal to
 248          * 100 microseconds.
 249          */
 250         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 251                 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 252                                   acpi_gbl_FADT.c2_latency);
 253                 /* invalidate C2 */
 254                 pr->power.states[ACPI_STATE_C2].address = 0;
 255         }
 256
 257         /*
 258          * FADT supplied C3 latency must be less than or equal to
 259          * 1000 microseconds.
 260          */
 261         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 262                 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 263                                   acpi_gbl_FADT.c3_latency);
 264                 /* invalidate C3 */
 265                 pr->power.states[ACPI_STATE_C3].address = 0;
 266         }
 267
 268         acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 269                           pr->power.states[ACPI_STATE_C2].address,
 270                           pr->power.states[ACPI_STATE_C3].address);
 271
 272         snprintf(pr->power.states[ACPI_STATE_C2].desc,
 273                          ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 274                          pr->power.states[ACPI_STATE_C2].address);
 275         snprintf(pr->power.states[ACPI_STATE_C3].desc,
 276                          ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 277                          pr->power.states[ACPI_STATE_C3].address);
 278
 279         if (!pr->power.states[ACPI_STATE_C2].address &&
 280             !pr->power.states[ACPI_STATE_C3].address)
 281                 return -ENODEV;
 282
 283         return 0;
 284 }
 285
 286 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 287 {
 288         if (!pr->power.states[ACPI_STATE_C1].valid) {
 289                 /* set the first C-State to C1 */
 290                 /* all processors need to support C1 */
 291                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 292                 pr->power.states[ACPI_STATE_C1].valid = 1;
 293                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 294
 295                 snprintf(pr->power.states[ACPI_STATE_C1].desc,
 296                          ACPI_CX_DESC_LEN, "ACPI HLT");
 297         }
 298         /* the C0 state only exists as a filler in our array */
 299         pr->power.states[ACPI_STATE_C0].valid = 1;
 300         return 0;
 301 }
 302
 303 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 304 {
 305         int ret;
 306
 307         if (nocst)
 308                 return -ENODEV;
 309
 310         ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 311         if (ret)
 312                 return ret;
 313
 314         if (!pr->power.count)
 315                 return -EFAULT;
 316
 317         pr->flags.has_cst = 1;
 318         return 0;
 319 }
 320
 321 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 322                                            struct acpi_processor_cx *cx)
 323 {
 324         static int bm_check_flag = -1;
 325         static int bm_control_flag = -1;
 326
 327
 328         if (!cx->address)
 329                 return;
 330
 331         /*
 332          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 333          * DMA transfers are used by any ISA device to avoid livelock.
 334          * Note that we could disable Type-F DMA (as recommended by
 335          * the erratum), but this is known to disrupt certain ISA
 336          * devices thus we take the conservative approach.
 337          */
 338         if (errata.piix4.fdma) {
 339                 acpi_handle_debug(pr->handle,
 340                                   "C3 not supported on PIIX4 with Type-F DMA\n");
 341                 return;
 342         }
 343
 344         /* All the logic here assumes flags.bm_check is same across all CPUs */
 345         if (bm_check_flag == -1) {
 346                 /* Determine whether bm_check is needed based on CPU  */
 347                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 348                 bm_check_flag = pr->flags.bm_check;
 349                 bm_control_flag = pr->flags.bm_control;
 350         } else {
 351                 pr->flags.bm_check = bm_check_flag;
 352                 pr->flags.bm_control = bm_control_flag;
 353         }
 354
 355         if (pr->flags.bm_check) {
 356                 if (!pr->flags.bm_control) {
 357                         if (pr->flags.has_cst != 1) {
 358                                 /* bus mastering control is necessary */
 359                                 acpi_handle_debug(pr->handle,
 360                                                   "C3 support requires BM control\n");
 361                                 return;
 362                         } else {
 363                                 /* Here we enter C3 without bus mastering */
 364                                 acpi_handle_debug(pr->handle,
 365                                                   "C3 support without BM control\n");
 366                         }
 367                 }
 368         } else {
 369                 /*
 370                  * WBINVD should be set in fadt, for C3 state to be
 371                  * supported on when bm_check is not required.
 372                  */
 373                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 374                         acpi_handle_debug(pr->handle,
 375                                           "Cache invalidation should work properly"
 376                                           " for C3 to be enabled on SMP systems\n");
 377                         return;
 378                 }
 379         }
 380
 381         /*
 382          * Otherwise we've met all of our C3 requirements.
 383          * Normalize the C3 latency to expidite policy.  Enable
 384          * checking of bus mastering status (bm_check) so we can
 385          * use this in our C3 policy
 386          */
 387         cx->valid = 1;
 388
 389         /*
 390          * On older chipsets, BM_RLD needs to be set
 391          * in order for Bus Master activity to wake the
 392          * system from C3.  Newer chipsets handle DMA
 393          * during C3 automatically and BM_RLD is a NOP.
 394          * In either case, the proper way to
 395          * handle BM_RLD is to set it and leave it set.
 396          */
 397         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 398 }
 399
 400 static void acpi_cst_latency_sort(struct acpi_processor_cx *states, size_t length)
 401 {
 402         int i, j, k;
 403
 404         for (i = 1; i < length; i++) {
 405                 if (!states[i].valid)
 406                         continue;
 407
 408                 for (j = i - 1, k = i; j >= 0; j--) {
 409                         if (!states[j].valid)
 410                                 continue;
 411
 412                         if (states[j].latency > states[k].latency)
 413                                 swap(states[j].latency, states[k].latency);
 414
 415                         k = j;
 416                 }
 417         }
 418 }
 419
 420 static int acpi_processor_power_verify(struct acpi_processor *pr)
 421 {
 422         unsigned int i;
 423         unsigned int working = 0;
 424         unsigned int last_latency = 0;
 425         unsigned int last_type = 0;
 426         bool buggy_latency = false;
 427
 428         pr->power.timer_broadcast_on_state = INT_MAX;
 429
 430         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 431                 struct acpi_processor_cx *cx = &pr->power.states[i];
 432
 433                 switch (cx->type) {
 434                 case ACPI_STATE_C1:
 435                         cx->valid = 1;
 436                         break;
 437
 438                 case ACPI_STATE_C2:
 439                         if (!cx->address)
 440                                 break;
 441                         cx->valid = 1;
 442                         break;
 443
 444                 case ACPI_STATE_C3:
 445                         acpi_processor_power_verify_c3(pr, cx);
 446                         break;
 447                 }
 448                 if (!cx->valid)
 449                         continue;
 450                 if (cx->type >= last_type && cx->latency < last_latency)
 451                         buggy_latency = true;
 452                 last_latency = cx->latency;
 453                 last_type = cx->type;
 454
 455                 lapic_timer_check_state(i, pr, cx);
 456                 tsc_check_state(cx->type);
 457                 working++;
 458         }
 459
 460         if (buggy_latency) {
 461                 pr_notice("FW issue: working around C-state latencies out of order\n");
 462                 acpi_cst_latency_sort(&pr->power.states[1], max_cstate);
 463         }
 464
 465         lapic_timer_propagate_broadcast(pr);
 466
 467         return working;
 468 }
 469
 470 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 471 {
 472         int result;
 473
 474         /* NOTE: the idle thread may not be running while calling
 475          * this function */
 476
 477         /* Zero initialize all the C-states info. */
 478         memset(pr->power.states, 0, sizeof(pr->power.states));
 479
 480         result = acpi_processor_get_power_info_cst(pr);
 481         if (result == -ENODEV)
 482                 result = acpi_processor_get_power_info_fadt(pr);
 483
 484         if (result)
 485                 return result;
 486
 487         acpi_processor_get_power_info_default(pr);
 488
 489         pr->power.count = acpi_processor_power_verify(pr);
 490         pr->flags.power = 1;
 491
 492         return 0;
 493 }
 494
 495 /**
 496  * acpi_idle_bm_check - checks if bus master activity was detected
 497  */
 498 static int acpi_idle_bm_check(void)
 499 {
 500         u32 bm_status = 0;
 501
 502         if (bm_check_disable)
 503                 return 0;
 504
 505         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 506         if (bm_status)
 507                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 508         /*
 509          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 510          * the true state of bus mastering activity; forcing us to
 511          * manually check the BMIDEA bit of each IDE channel.
 512          */
 513         else if (errata.piix4.bmisx) {
 514                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 515                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 516                         bm_status = 1;
 517         }
 518         return bm_status;
 519 }
 520
 521 static __cpuidle void io_idle(unsigned long addr)
 522 {
 523         /* IO port based C-state */
 524         inb(addr);
 525
 526 #ifdef  CONFIG_X86
 527         /* No delay is needed if we are in guest */
 528         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 529                 return;
 530         /*
 531          * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
 532          * not this code.  Assume that any Intel systems using this
 533          * are ancient and may need the dummy wait.  This also assumes
 534          * that the motivating chipset issue was Intel-only.
 535          */
 536         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 537                 return;
 538 #endif
 539         /*
 540          * Dummy wait op - must do something useless after P_LVL2 read
 541          * because chipsets cannot guarantee that STPCLK# signal gets
 542          * asserted in time to freeze execution properly
 543          *
 544          * This workaround has been in place since the original ACPI
 545          * implementation was merged, circa 2002.
 546          *
 547          * If a profile is pointing to this instruction, please first
 548          * consider moving your system to a more modern idle
 549          * mechanism.
 550          */
 551         inl(acpi_gbl_FADT.xpm_timer_block.address);
 552 }
 553
 554 /**
 555  * acpi_idle_do_entry - enter idle state using the appropriate method
 556  * @cx: cstate data
 557  *
 558  * Caller disables interrupt before call and enables interrupt after return.
 559  */
 560 static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 561 {
 562         perf_lopwr_cb(true);
 563
 564         if (cx->entry_method == ACPI_CSTATE_FFH) {
 565                 /* Call into architectural FFH based C-state */
 566                 acpi_processor_ffh_cstate_enter(cx);
 567         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 568                 acpi_safe_halt();
 569         } else {
 570                 io_idle(cx->address);
 571         }
 572
 573         perf_lopwr_cb(false);
 574 }
 575
 576 /**
 577  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 578  * @dev: the target CPU
 579  * @index: the index of suggested state
 580  */
 581 static void acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 582 {
 583         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 584
 585         ACPI_FLUSH_CPU_CACHE();
 586
 587         while (1) {
 588
 589                 if (cx->entry_method == ACPI_CSTATE_HALT)
 590                         raw_safe_halt();
 591                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 592                         io_idle(cx->address);
 593                 } else if (cx->entry_method == ACPI_CSTATE_FFH) {
 594                         acpi_processor_ffh_play_dead(cx);
 595                 } else
 596                         return;
 597         }
 598 }
 599
 600 static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 601 {
 602         return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 603                 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 604 }
 605
 606 static int c3_cpu_count;
 607 static DEFINE_RAW_SPINLOCK(c3_lock);
 608
 609 /**
 610  * acpi_idle_enter_bm - enters C3 with proper BM handling
 611  * @drv: cpuidle driver
 612  * @pr: Target processor
 613  * @cx: Target state context
 614  * @index: index of target state
 615  */
 616 static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
 617                                struct acpi_processor *pr,
 618                                struct acpi_processor_cx *cx,
 619                                int index)
 620 {
 621         static struct acpi_processor_cx safe_cx = {
 622                 .entry_method = ACPI_CSTATE_HALT,
 623         };
 624
 625         /*
 626          * disable bus master
 627          * bm_check implies we need ARB_DIS
 628          * bm_control implies whether we can do ARB_DIS
 629          *
 630          * That leaves a case where bm_check is set and bm_control is not set.
 631          * In that case we cannot do much, we enter C3 without doing anything.
 632          */
 633         bool dis_bm = pr->flags.bm_control;
 634
 635         instrumentation_begin();
 636
 637         /* If we can skip BM, demote to a safe state. */
 638         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 639                 dis_bm = false;
 640                 index = drv->safe_state_index;
 641                 if (index >= 0) {
 642                         cx = this_cpu_read(acpi_cstate[index]);
 643                 } else {
 644                         cx = &safe_cx;
 645                         index = -EBUSY;
 646                 }
 647         }
 648
 649         if (dis_bm) {
 650                 raw_spin_lock(&c3_lock);
 651                 c3_cpu_count++;
 652                 /* Disable bus master arbitration when all CPUs are in C3 */
 653                 if (c3_cpu_count == num_online_cpus())
 654                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 655                 raw_spin_unlock(&c3_lock);
 656         }
 657
 658         ct_cpuidle_enter();
 659
 660         acpi_idle_do_entry(cx);
 661
 662         ct_cpuidle_exit();
 663
 664         /* Re-enable bus master arbitration */
 665         if (dis_bm) {
 666                 raw_spin_lock(&c3_lock);
 667                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 668                 c3_cpu_count--;
 669                 raw_spin_unlock(&c3_lock);
 670         }
 671
 672         instrumentation_end();
 673
 674         return index;
 675 }
 676
 677 static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
 678                            struct cpuidle_driver *drv, int index)
 679 {
 680         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 681         struct acpi_processor *pr;
 682
 683         pr = __this_cpu_read(processors);
 684         if (unlikely(!pr))
 685                 return -EINVAL;
 686
 687         if (cx->type != ACPI_STATE_C1) {
 688                 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 689                         return acpi_idle_enter_bm(drv, pr, cx, index);
 690
 691                 /* C2 to C1 demotion. */
 692                 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 693                         index = ACPI_IDLE_STATE_START;
 694                         cx = per_cpu(acpi_cstate[index], dev->cpu);
 695                 }
 696         }
 697
 698         if (cx->type == ACPI_STATE_C3)
 699                 ACPI_FLUSH_CPU_CACHE();
 700
 701         acpi_idle_do_entry(cx);
 702
 703         return index;
 704 }
 705
 706 static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 707                                   struct cpuidle_driver *drv, int index)
 708 {
 709         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 710
 711         if (cx->type == ACPI_STATE_C3) {
 712                 struct acpi_processor *pr = __this_cpu_read(processors);
 713
 714                 if (unlikely(!pr))
 715                         return 0;
 716
 717                 if (pr->flags.bm_check) {
 718                         u8 bm_sts_skip = cx->bm_sts_skip;
 719
 720                         /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 721                         cx->bm_sts_skip = 1;
 722                         acpi_idle_enter_bm(drv, pr, cx, index);
 723                         cx->bm_sts_skip = bm_sts_skip;
 724
 725                         return 0;
 726                 } else {
 727                         ACPI_FLUSH_CPU_CACHE();
 728                 }
 729         }
 730         acpi_idle_do_entry(cx);
 731
 732         return 0;
 733 }
 734
 735 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 736                                            struct cpuidle_device *dev)
 737 {
 738         int i, count = ACPI_IDLE_STATE_START;
 739         struct acpi_processor_cx *cx;
 740         struct cpuidle_state *state;
 741
 742         if (max_cstate == 0)
 743                 max_cstate = 1;
 744
 745         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 746                 state = &acpi_idle_driver.states[count];
 747                 cx = &pr->power.states[i];
 748
 749                 if (!cx->valid)
 750                         continue;
 751
 752                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
 753
 754                 if (lapic_timer_needs_broadcast(pr, cx))
 755                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 756
 757                 if (cx->type == ACPI_STATE_C3) {
 758                         state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 759                         if (pr->flags.bm_check)
 760                                 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 761                 }
 762
 763                 count++;
 764                 if (count == CPUIDLE_STATE_MAX)
 765                         break;
 766         }
 767
 768         if (!count)
 769                 return -EINVAL;
 770
 771         return 0;
 772 }
 773
 774 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 775 {
 776         int i, count;
 777         struct acpi_processor_cx *cx;
 778         struct cpuidle_state *state;
 779         struct cpuidle_driver *drv = &acpi_idle_driver;
 780
 781         if (max_cstate == 0)
 782                 max_cstate = 1;
 783
 784         if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 785                 cpuidle_poll_state_init(drv);
 786                 count = 1;
 787         } else {
 788                 count = 0;
 789         }
 790
 791         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 792                 cx = &pr->power.states[i];
 793
 794                 if (!cx->valid)
 795                         continue;
 796
 797                 state = &drv->states[count];
 798                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 799                 strscpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 800                 state->exit_latency = cx->latency;
 801                 state->target_residency = cx->latency * latency_factor;
 802                 state->enter = acpi_idle_enter;
 803
 804                 state->flags = 0;
 805
 806                 state->enter_dead = acpi_idle_play_dead;
 807
 808                 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2)
 809                         drv->safe_state_index = count;
 810
 811                 /*
 812                  * Halt-induced C1 is not good for ->enter_s2idle, because it
 813                  * re-enables interrupts on exit.  Moreover, C1 is generally not
 814                  * particularly interesting from the suspend-to-idle angle, so
 815                  * avoid C1 and the situations in which we may need to fall back
 816                  * to it altogether.
 817                  */
 818                 if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
 819                         state->enter_s2idle = acpi_idle_enter_s2idle;
 820
 821                 count++;
 822                 if (count == CPUIDLE_STATE_MAX)
 823                         break;
 824         }
 825
 826         drv->state_count = count;
 827
 828         if (!count)
 829                 return -EINVAL;
 830
 831         return 0;
 832 }
 833
 834 static inline void acpi_processor_cstate_first_run_checks(void)
 835 {
 836         static int first_run;
 837
 838         if (first_run)
 839                 return;
 840         dmi_check_system(processor_power_dmi_table);
 841         max_cstate = acpi_processor_cstate_check(max_cstate);
 842         if (max_cstate < ACPI_C_STATES_MAX)
 843                 pr_notice("processor limited to max C-state %d\n", max_cstate);
 844
 845         first_run++;
 846
 847         if (nocst)
 848                 return;
 849
 850         acpi_processor_claim_cst_control();
 851 }
 852 #else
 853
 854 static inline int disabled_by_idle_boot_param(void) { return 0; }
 855 static inline void acpi_processor_cstate_first_run_checks(void) { }
 856 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 857 {
 858         return -ENODEV;
 859 }
 860
 861 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 862                                            struct cpuidle_device *dev)
 863 {
 864         return -EINVAL;
 865 }
 866
 867 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 868 {
 869         return -EINVAL;
 870 }
 871
 872 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 873
 874 struct acpi_lpi_states_array {
 875         unsigned int size;
 876         unsigned int composite_states_size;
 877         struct acpi_lpi_state *entries;
 878         struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
 879 };
 880
 881 static int obj_get_integer(union acpi_object *obj, u32 *value)
 882 {
 883         if (obj->type != ACPI_TYPE_INTEGER)
 884                 return -EINVAL;
 885
 886         *value = obj->integer.value;
 887         return 0;
 888 }
 889
 890 static int acpi_processor_evaluate_lpi(acpi_handle handle,
 891                                        struct acpi_lpi_states_array *info)
 892 {
 893         acpi_status status;
 894         int ret = 0;
 895         int pkg_count, state_idx = 1, loop;
 896         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 897         union acpi_object *lpi_data;
 898         struct acpi_lpi_state *lpi_state;
 899
 900         status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
 901         if (ACPI_FAILURE(status)) {
 902                 acpi_handle_debug(handle, "No _LPI, giving up\n");
 903                 return -ENODEV;
 904         }
 905
 906         lpi_data = buffer.pointer;
 907
 908         /* There must be at least 4 elements = 3 elements + 1 package */
 909         if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
 910             lpi_data->package.count < 4) {
 911                 pr_debug("not enough elements in _LPI\n");
 912                 ret = -ENODATA;
 913                 goto end;
 914         }
 915
 916         pkg_count = lpi_data->package.elements[2].integer.value;
 917
 918         /* Validate number of power states. */
 919         if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
 920                 pr_debug("count given by _LPI is not valid\n");
 921                 ret = -ENODATA;
 922                 goto end;
 923         }
 924
 925         lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
 926         if (!lpi_state) {
 927                 ret = -ENOMEM;
 928                 goto end;
 929         }
 930
 931         info->size = pkg_count;
 932         info->entries = lpi_state;
 933
 934         /* LPI States start at index 3 */
 935         for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
 936                 union acpi_object *element, *pkg_elem, *obj;
 937
 938                 element = &lpi_data->package.elements[loop];
 939                 if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
 940                         continue;
 941
 942                 pkg_elem = element->package.elements;
 943
 944                 obj = pkg_elem + 6;
 945                 if (obj->type == ACPI_TYPE_BUFFER) {
 946                         struct acpi_power_register *reg;
 947
 948                         reg = (struct acpi_power_register *)obj->buffer.pointer;
 949                         if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 950                             reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
 951                                 continue;
 952
 953                         lpi_state->address = reg->address;
 954                         lpi_state->entry_method =
 955                                 reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
 956                                 ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
 957                 } else if (obj->type == ACPI_TYPE_INTEGER) {
 958                         lpi_state->entry_method = ACPI_CSTATE_INTEGER;
 959                         lpi_state->address = obj->integer.value;
 960                 } else {
 961                         continue;
 962                 }
 963
 964                 /* elements[7,8] skipped for now i.e. Residency/Usage counter*/
 965
 966                 obj = pkg_elem + 9;
 967                 if (obj->type == ACPI_TYPE_STRING)
 968                         strscpy(lpi_state->desc, obj->string.pointer,
 969                                 ACPI_CX_DESC_LEN);
 970
 971                 lpi_state->index = state_idx;
 972                 if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
 973                         pr_debug("No min. residency found, assuming 10 us\n");
 974                         lpi_state->min_residency = 10;
 975                 }
 976
 977                 if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
 978                         pr_debug("No wakeup residency found, assuming 10 us\n");
 979                         lpi_state->wake_latency = 10;
 980                 }
 981
 982                 if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
 983                         lpi_state->flags = 0;
 984
 985                 if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
 986                         lpi_state->arch_flags = 0;
 987
 988                 if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
 989                         lpi_state->res_cnt_freq = 1;
 990
 991                 if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
 992                         lpi_state->enable_parent_state = 0;
 993         }
 994
 995         acpi_handle_debug(handle, "Found %d power states\n", state_idx);
 996 end:
 997         kfree(buffer.pointer);
 998         return ret;
 999 }
1000
1001 /*
1002  * flat_state_cnt - the number of composite LPI states after the process of flattening
1003  */
1004 static int flat_state_cnt;
1005
1006 /**
1007  * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
1008  *
1009  * @local: local LPI state
1010  * @parent: parent LPI state
1011  * @result: composite LPI state
1012  */
1013 static bool combine_lpi_states(struct acpi_lpi_state *local,
1014                                struct acpi_lpi_state *parent,
1015                                struct acpi_lpi_state *result)
1016 {
1017         if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1018                 if (!parent->address) /* 0 means autopromotable */
1019                         return false;
1020                 result->address = local->address + parent->address;
1021         } else {
1022                 result->address = parent->address;
1023         }
1024
1025         result->min_residency = max(local->min_residency, parent->min_residency);
1026         result->wake_latency = local->wake_latency + parent->wake_latency;
1027         result->enable_parent_state = parent->enable_parent_state;
1028         result->entry_method = local->entry_method;
1029
1030         result->flags = parent->flags;
1031         result->arch_flags = parent->arch_flags;
1032         result->index = parent->index;
1033
1034         strscpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
1035         strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
1036         strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
1037         return true;
1038 }
1039
1040 #define ACPI_LPI_STATE_FLAGS_ENABLED                    BIT(0)
1041
1042 static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1043                                   struct acpi_lpi_state *t)
1044 {
1045         curr_level->composite_states[curr_level->composite_states_size++] = t;
1046 }
1047
1048 static int flatten_lpi_states(struct acpi_processor *pr,
1049                               struct acpi_lpi_states_array *curr_level,
1050                               struct acpi_lpi_states_array *prev_level)
1051 {
1052         int i, j, state_count = curr_level->size;
1053         struct acpi_lpi_state *p, *t = curr_level->entries;
1054
1055         curr_level->composite_states_size = 0;
1056         for (j = 0; j < state_count; j++, t++) {
1057                 struct acpi_lpi_state *flpi;
1058
1059                 if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1060                         continue;
1061
1062                 if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1063                         pr_warn("Limiting number of LPI states to max (%d)\n",
1064                                 ACPI_PROCESSOR_MAX_POWER);
1065                         pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1066                         break;
1067                 }
1068
1069                 flpi = &pr->power.lpi_states[flat_state_cnt];
1070
1071                 if (!prev_level) { /* leaf/processor node */
1072                         memcpy(flpi, t, sizeof(*t));
1073                         stash_composite_state(curr_level, flpi);
1074                         flat_state_cnt++;
1075                         continue;
1076                 }
1077
1078                 for (i = 0; i < prev_level->composite_states_size; i++) {
1079                         p = prev_level->composite_states[i];
1080                         if (t->index <= p->enable_parent_state &&
1081                             combine_lpi_states(p, t, flpi)) {
1082                                 stash_composite_state(curr_level, flpi);
1083                                 flat_state_cnt++;
1084                                 flpi++;
1085                         }
1086                 }
1087         }
1088
1089         kfree(curr_level->entries);
1090         return 0;
1091 }
1092
1093 int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1094 {
1095         return -EOPNOTSUPP;
1096 }
1097
1098 static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1099 {
1100         int ret, i;
1101         acpi_status status;
1102         acpi_handle handle = pr->handle, pr_ahandle;
1103         struct acpi_device *d = NULL;
1104         struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1105
1106         /* make sure our architecture has support */
1107         ret = acpi_processor_ffh_lpi_probe(pr->id);
1108         if (ret == -EOPNOTSUPP)
1109                 return ret;
1110
1111         if (!osc_pc_lpi_support_confirmed)
1112                 return -EOPNOTSUPP;
1113
1114         if (!acpi_has_method(handle, "_LPI"))
1115                 return -EINVAL;
1116
1117         flat_state_cnt = 0;
1118         prev = &info[0];
1119         curr = &info[1];
1120         handle = pr->handle;
1121         ret = acpi_processor_evaluate_lpi(handle, prev);
1122         if (ret)
1123                 return ret;
1124         flatten_lpi_states(pr, prev, NULL);
1125
1126         status = acpi_get_parent(handle, &pr_ahandle);
1127         while (ACPI_SUCCESS(status)) {
1128                 d = acpi_fetch_acpi_dev(pr_ahandle);
1129                 if (!d)
1130                         break;
1131
1132                 handle = pr_ahandle;
1133
1134                 if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
1135                         break;
1136
1137                 /* can be optional ? */
1138                 if (!acpi_has_method(handle, "_LPI"))
1139                         break;
1140
1141                 ret = acpi_processor_evaluate_lpi(handle, curr);
1142                 if (ret)
1143                         break;
1144
1145                 /* flatten all the LPI states in this level of hierarchy */
1146                 flatten_lpi_states(pr, curr, prev);
1147
1148                 tmp = prev, prev = curr, curr = tmp;
1149
1150                 status = acpi_get_parent(handle, &pr_ahandle);
1151         }
1152
1153         pr->power.count = flat_state_cnt;
1154         /* reset the index after flattening */
1155         for (i = 0; i < pr->power.count; i++)
1156                 pr->power.lpi_states[i].index = i;
1157
1158         /* Tell driver that _LPI is supported. */
1159         pr->flags.has_lpi = 1;
1160         pr->flags.power = 1;
1161
1162         return 0;
1163 }
1164
1165 int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1166 {
1167         return -ENODEV;
1168 }
1169
1170 /**
1171  * acpi_idle_lpi_enter - enters an ACPI any LPI state
1172  * @dev: the target CPU
1173  * @drv: cpuidle driver containing cpuidle state info
1174  * @index: index of target state
1175  *
1176  * Return: 0 for success or negative value for error
1177  */
1178 static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1179                                struct cpuidle_driver *drv, int index)
1180 {
1181         struct acpi_processor *pr;
1182         struct acpi_lpi_state *lpi;
1183
1184         pr = __this_cpu_read(processors);
1185
1186         if (unlikely(!pr))
1187                 return -EINVAL;
1188
1189         lpi = &pr->power.lpi_states[index];
1190         if (lpi->entry_method == ACPI_CSTATE_FFH)
1191                 return acpi_processor_ffh_lpi_enter(lpi);
1192
1193         return -EINVAL;
1194 }
1195
1196 static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1197 {
1198         int i;
1199         struct acpi_lpi_state *lpi;
1200         struct cpuidle_state *state;
1201         struct cpuidle_driver *drv = &acpi_idle_driver;
1202
1203         if (!pr->flags.has_lpi)
1204                 return -EOPNOTSUPP;
1205
1206         for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1207                 lpi = &pr->power.lpi_states[i];
1208
1209                 state = &drv->states[i];
1210                 snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
1211                 strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
1212                 state->exit_latency = lpi->wake_latency;
1213                 state->target_residency = lpi->min_residency;
1214                 state->flags |= arch_get_idle_state_flags(lpi->arch_flags);
1215                 if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
1216                         state->flags |= CPUIDLE_FLAG_RCU_IDLE;
1217                 state->enter = acpi_idle_lpi_enter;
1218                 drv->safe_state_index = i;
1219         }
1220
1221         drv->state_count = i;
1222
1223         return 0;
1224 }
1225
1226 /**
1227  * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1228  * global state data i.e. idle routines
1229  *
1230  * @pr: the ACPI processor
1231  */
1232 static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1233 {
1234         int i;
1235         struct cpuidle_driver *drv = &acpi_idle_driver;
1236
1237         if (!pr->flags.power_setup_done || !pr->flags.power)
1238                 return -EINVAL;
1239
1240         drv->safe_state_index = -1;
1241         for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1242                 drv->states[i].name[0] = '\0';
1243                 drv->states[i].desc[0] = '\0';
1244         }
1245
1246         if (pr->flags.has_lpi)
1247                 return acpi_processor_setup_lpi_states(pr);
1248
1249         return acpi_processor_setup_cstates(pr);
1250 }
1251
1252 /**
1253  * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1254  * device i.e. per-cpu data
1255  *
1256  * @pr: the ACPI processor
1257  * @dev : the cpuidle device
1258  */
1259 static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1260                                             struct cpuidle_device *dev)
1261 {
1262         if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1263                 return -EINVAL;
1264
1265         dev->cpu = pr->id;
1266         if (pr->flags.has_lpi)
1267                 return acpi_processor_ffh_lpi_probe(pr->id);
1268
1269         return acpi_processor_setup_cpuidle_cx(pr, dev);
1270 }
1271
1272 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1273 {
1274         int ret;
1275
1276         ret = acpi_processor_get_lpi_info(pr);
1277         if (ret)
1278                 ret = acpi_processor_get_cstate_info(pr);
1279
1280         return ret;
1281 }
1282
1283 int acpi_processor_hotplug(struct acpi_processor *pr)
1284 {
1285         int ret = 0;
1286         struct cpuidle_device *dev;
1287
1288         if (disabled_by_idle_boot_param())
1289                 return 0;
1290
1291         if (!pr->flags.power_setup_done)
1292                 return -ENODEV;
1293
1294         dev = per_cpu(acpi_cpuidle_device, pr->id);
1295         cpuidle_pause_and_lock();
1296         cpuidle_disable_device(dev);
1297         ret = acpi_processor_get_power_info(pr);
1298         if (!ret && pr->flags.power) {
1299                 acpi_processor_setup_cpuidle_dev(pr, dev);
1300                 ret = cpuidle_enable_device(dev);
1301         }
1302         cpuidle_resume_and_unlock();
1303
1304         return ret;
1305 }
1306
1307 int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1308 {
1309         int cpu;
1310         struct acpi_processor *_pr;
1311         struct cpuidle_device *dev;
1312
1313         if (disabled_by_idle_boot_param())
1314                 return 0;
1315
1316         if (!pr->flags.power_setup_done)
1317                 return -ENODEV;
1318
1319         /*
1320          * FIXME:  Design the ACPI notification to make it once per
1321          * system instead of once per-cpu.  This condition is a hack
1322          * to make the code that updates C-States be called once.
1323          */
1324
1325         if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1326
1327                 /* Protect against cpu-hotplug */
1328                 cpus_read_lock();
1329                 cpuidle_pause_and_lock();
1330
1331                 /* Disable all cpuidle devices */
1332                 for_each_online_cpu(cpu) {
1333                         _pr = per_cpu(processors, cpu);
1334                         if (!_pr || !_pr->flags.power_setup_done)
1335                                 continue;
1336                         dev = per_cpu(acpi_cpuidle_device, cpu);
1337                         cpuidle_disable_device(dev);
1338                 }
1339
1340                 /* Populate Updated C-state information */
1341                 acpi_processor_get_power_info(pr);
1342                 acpi_processor_setup_cpuidle_states(pr);
1343
1344                 /* Enable all cpuidle devices */
1345                 for_each_online_cpu(cpu) {
1346                         _pr = per_cpu(processors, cpu);
1347                         if (!_pr || !_pr->flags.power_setup_done)
1348                                 continue;
1349                         acpi_processor_get_power_info(_pr);
1350                         if (_pr->flags.power) {
1351                                 dev = per_cpu(acpi_cpuidle_device, cpu);
1352                                 acpi_processor_setup_cpuidle_dev(_pr, dev);
1353                                 cpuidle_enable_device(dev);
1354                         }
1355                 }
1356                 cpuidle_resume_and_unlock();
1357                 cpus_read_unlock();
1358         }
1359
1360         return 0;
1361 }
1362
1363 static int acpi_processor_registered;
1364
1365 int acpi_processor_power_init(struct acpi_processor *pr)
1366 {
1367         int retval;
1368         struct cpuidle_device *dev;
1369
1370         if (disabled_by_idle_boot_param())
1371                 return 0;
1372
1373         acpi_processor_cstate_first_run_checks();
1374
1375         if (!acpi_processor_get_power_info(pr))
1376                 pr->flags.power_setup_done = 1;
1377
1378         /*
1379          * Install the idle handler if processor power management is supported.
1380          * Note that we use previously set idle handler will be used on
1381          * platforms that only support C1.
1382          */
1383         if (pr->flags.power) {
1384                 /* Register acpi_idle_driver if not already registered */
1385                 if (!acpi_processor_registered) {
1386                         acpi_processor_setup_cpuidle_states(pr);
1387                         retval = cpuidle_register_driver(&acpi_idle_driver);
1388                         if (retval)
1389                                 return retval;
1390                         pr_debug("%s registered with cpuidle\n",
1391                                  acpi_idle_driver.name);
1392                 }
1393
1394                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1395                 if (!dev)
1396                         return -ENOMEM;
1397                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1398
1399                 acpi_processor_setup_cpuidle_dev(pr, dev);
1400
1401                 /* Register per-cpu cpuidle_device. Cpuidle driver
1402                  * must already be registered before registering device
1403                  */
1404                 retval = cpuidle_register_device(dev);
1405                 if (retval) {
1406                         if (acpi_processor_registered == 0)
1407                                 cpuidle_unregister_driver(&acpi_idle_driver);
1408                         return retval;
1409                 }
1410                 acpi_processor_registered++;
1411         }
1412         return 0;
1413 }
1414
1415 int acpi_processor_power_exit(struct acpi_processor *pr)
1416 {
1417         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1418
1419         if (disabled_by_idle_boot_param())
1420                 return 0;
1421
1422         if (pr->flags.power) {
1423                 cpuidle_unregister_device(dev);
1424                 acpi_processor_registered--;
1425                 if (acpi_processor_registered == 0)
1426                         cpuidle_unregister_driver(&acpi_idle_driver);
1427
1428                 kfree(dev);
1429         }
1430
1431         pr->flags.power_setup_done = 0;
1432         return 0;
1433 }