drivers/acpi/sleep.c

   1 /*
   2  * sleep.c - ACPI sleep support.
   3  *
   4  * Copyright (c) 2005 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   5  * Copyright (c) 2004 David Shaohua Li <shaohua.li@intel.com>
   6  * Copyright (c) 2000-2003 Patrick Mochel
   7  * Copyright (c) 2003 Open Source Development Lab
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/irq.h>
  15 #include <linux/dmi.h>
  16 #include <linux/device.h>
  17 #include <linux/suspend.h>
  18 #include <linux/reboot.h>
  19
  20 #include <asm/io.h>
  21
  22 #include <acpi/acpi_bus.h>
  23 #include <acpi/acpi_drivers.h>
  24
  25 #include "internal.h"
  26 #include "sleep.h"
  27
  28 u8 sleep_states[ACPI_S_STATE_COUNT];
  29
  30 static void acpi_sleep_tts_switch(u32 acpi_state)
  31 {
  32         union acpi_object in_arg = { ACPI_TYPE_INTEGER };
  33         struct acpi_object_list arg_list = { 1, &in_arg };
  34         acpi_status status = AE_OK;
  35
  36         in_arg.integer.value = acpi_state;
  37         status = acpi_evaluate_object(NULL, "\\_TTS", &arg_list, NULL);
  38         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
  39                 /*
  40                  * OS can't evaluate the _TTS object correctly. Some warning
  41                  * message will be printed. But it won't break anything.
  42                  */
  43                 printk(KERN_NOTICE "Failure in evaluating _TTS object\n");
  44         }
  45 }
  46
  47 static int tts_notify_reboot(struct notifier_block *this,
  48                         unsigned long code, void *x)
  49 {
  50         acpi_sleep_tts_switch(ACPI_STATE_S5);
  51         return NOTIFY_DONE;
  52 }
  53
  54 static struct notifier_block tts_notifier = {
  55         .notifier_call  = tts_notify_reboot,
  56         .next           = NULL,
  57         .priority       = 0,
  58 };
  59
  60 static int acpi_sleep_prepare(u32 acpi_state)
  61 {
  62 #ifdef CONFIG_ACPI_SLEEP
  63         /* do we have a wakeup address for S2 and S3? */
  64         if (acpi_state == ACPI_STATE_S3) {
  65                 if (!acpi_wakeup_address) {
  66                         return -EFAULT;
  67                 }
  68                 acpi_set_firmware_waking_vector(
  69                                 (acpi_physical_address)acpi_wakeup_address);
  70
  71         }
  72         ACPI_FLUSH_CPU_CACHE();
  73         acpi_enable_wakeup_device_prep(acpi_state);
  74 #endif
  75         printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
  76                 acpi_state);
  77         acpi_enter_sleep_state_prep(acpi_state);
  78         return 0;
  79 }
  80
  81 #ifdef CONFIG_ACPI_SLEEP
  82 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
  83 /*
  84  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
  85  * user to request that behavior by using the 'acpi_old_suspend_ordering'
  86  * kernel command line option that causes the following variable to be set.
  87  */
  88 static bool old_suspend_ordering;
  89
  90 void __init acpi_old_suspend_ordering(void)
  91 {
  92         old_suspend_ordering = true;
  93 }
  94
  95 /**
  96  *      acpi_pm_disable_gpes - Disable the GPEs.
  97  */
  98 static int acpi_pm_disable_gpes(void)
  99 {
 100         acpi_disable_all_gpes();
 101         return 0;
 102 }
 103
 104 /**
 105  *      __acpi_pm_prepare - Prepare the platform to enter the target state.
 106  *
 107  *      If necessary, set the firmware waking vector and do arch-specific
 108  *      nastiness to get the wakeup code to the waking vector.
 109  */
 110 static int __acpi_pm_prepare(void)
 111 {
 112         int error = acpi_sleep_prepare(acpi_target_sleep_state);
 113
 114         if (error)
 115                 acpi_target_sleep_state = ACPI_STATE_S0;
 116         return error;
 117 }
 118
 119 /**
 120  *      acpi_pm_prepare - Prepare the platform to enter the target sleep
 121  *              state and disable the GPEs.
 122  */
 123 static int acpi_pm_prepare(void)
 124 {
 125         int error = __acpi_pm_prepare();
 126
 127         if (!error)
 128                 acpi_disable_all_gpes();
 129         return error;
 130 }
 131
 132 /**
 133  *      acpi_pm_finish - Instruct the platform to leave a sleep state.
 134  *
 135  *      This is called after we wake back up (or if entering the sleep state
 136  *      failed).
 137  */
 138 static void acpi_pm_finish(void)
 139 {
 140         u32 acpi_state = acpi_target_sleep_state;
 141
 142         if (acpi_state == ACPI_STATE_S0)
 143                 return;
 144
 145         printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
 146                 acpi_state);
 147         acpi_disable_wakeup_device(acpi_state);
 148         acpi_leave_sleep_state(acpi_state);
 149
 150         /* reset firmware waking vector */
 151         acpi_set_firmware_waking_vector((acpi_physical_address) 0);
 152
 153         acpi_target_sleep_state = ACPI_STATE_S0;
 154 }
 155
 156 /**
 157  *      acpi_pm_end - Finish up suspend sequence.
 158  */
 159 static void acpi_pm_end(void)
 160 {
 161         /*
 162          * This is necessary in case acpi_pm_finish() is not called during a
 163          * failing transition to a sleep state.
 164          */
 165         acpi_target_sleep_state = ACPI_STATE_S0;
 166         acpi_sleep_tts_switch(acpi_target_sleep_state);
 167 }
 168 #else /* !CONFIG_ACPI_SLEEP */
 169 #define acpi_target_sleep_state ACPI_STATE_S0
 170 #endif /* CONFIG_ACPI_SLEEP */
 171
 172 #ifdef CONFIG_SUSPEND
 173 /*
 174  * According to the ACPI specification the BIOS should make sure that ACPI is
 175  * enabled and SCI_EN bit is set on wake-up from S1 - S3 sleep states.  Still,
 176  * some BIOSes don't do that and therefore we use acpi_enable() to enable ACPI
 177  * on such systems during resume.  Unfortunately that doesn't help in
 178  * particularly pathological cases in which SCI_EN has to be set directly on
 179  * resume, although the specification states very clearly that this flag is
 180  * owned by the hardware.  The set_sci_en_on_resume variable will be set in such
 181  * cases.
 182  */
 183 static bool set_sci_en_on_resume;
 184
 185 extern void do_suspend_lowlevel(void);
 186
 187 static u32 acpi_suspend_states[] = {
 188         [PM_SUSPEND_ON] = ACPI_STATE_S0,
 189         [PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
 190         [PM_SUSPEND_MEM] = ACPI_STATE_S3,
 191         [PM_SUSPEND_MAX] = ACPI_STATE_S5
 192 };
 193
 194 /**
 195  *      acpi_suspend_begin - Set the target system sleep state to the state
 196  *              associated with given @pm_state, if supported.
 197  */
 198 static int acpi_suspend_begin(suspend_state_t pm_state)
 199 {
 200         u32 acpi_state = acpi_suspend_states[pm_state];
 201         int error = 0;
 202
 203         if (sleep_states[acpi_state]) {
 204                 acpi_target_sleep_state = acpi_state;
 205                 acpi_sleep_tts_switch(acpi_target_sleep_state);
 206         } else {
 207                 printk(KERN_ERR "ACPI does not support this state: %d\n",
 208                         pm_state);
 209                 error = -ENOSYS;
 210         }
 211         return error;
 212 }
 213
 214 /**
 215  *      acpi_suspend_enter - Actually enter a sleep state.
 216  *      @pm_state: ignored
 217  *
 218  *      Flush caches and go to sleep. For STR we have to call arch-specific
 219  *      assembly, which in turn call acpi_enter_sleep_state().
 220  *      It's unfortunate, but it works. Please fix if you're feeling frisky.
 221  */
 222 static int acpi_suspend_enter(suspend_state_t pm_state)
 223 {
 224         acpi_status status = AE_OK;
 225         unsigned long flags = 0;
 226         u32 acpi_state = acpi_target_sleep_state;
 227
 228         ACPI_FLUSH_CPU_CACHE();
 229
 230         /* Do arch specific saving of state. */
 231         if (acpi_state == ACPI_STATE_S3) {
 232                 int error = acpi_save_state_mem();
 233
 234                 if (error)
 235                         return error;
 236         }
 237
 238         local_irq_save(flags);
 239         acpi_enable_wakeup_device(acpi_state);
 240         switch (acpi_state) {
 241         case ACPI_STATE_S1:
 242                 barrier();
 243                 status = acpi_enter_sleep_state(acpi_state);
 244                 break;
 245
 246         case ACPI_STATE_S3:
 247                 do_suspend_lowlevel();
 248                 break;
 249         }
 250
 251         /* If ACPI is not enabled by the BIOS, we need to enable it here. */
 252         if (set_sci_en_on_resume)
 253                 acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
 254         else
 255                 acpi_enable();
 256
 257         /* Reprogram control registers and execute _BFS */
 258         acpi_leave_sleep_state_prep(acpi_state);
 259
 260         /* ACPI 3.0 specs (P62) says that it's the responsibility
 261          * of the OSPM to clear the status bit [ implying that the
 262          * POWER_BUTTON event should not reach userspace ]
 263          */
 264         if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3))
 265                 acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
 266
 267         /*
 268          * Disable and clear GPE status before interrupt is enabled. Some GPEs
 269          * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
 270          * acpi_leave_sleep_state will reenable specific GPEs later
 271          */
 272         acpi_disable_all_gpes();
 273
 274         local_irq_restore(flags);
 275         printk(KERN_DEBUG "Back to C!\n");
 276
 277         /* restore processor state */
 278         if (acpi_state == ACPI_STATE_S3)
 279                 acpi_restore_state_mem();
 280
 281         return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 282 }
 283
 284 static int acpi_suspend_state_valid(suspend_state_t pm_state)
 285 {
 286         u32 acpi_state;
 287
 288         switch (pm_state) {
 289         case PM_SUSPEND_ON:
 290         case PM_SUSPEND_STANDBY:
 291         case PM_SUSPEND_MEM:
 292                 acpi_state = acpi_suspend_states[pm_state];
 293
 294                 return sleep_states[acpi_state];
 295         default:
 296                 return 0;
 297         }
 298 }
 299
 300 static struct platform_suspend_ops acpi_suspend_ops = {
 301         .valid = acpi_suspend_state_valid,
 302         .begin = acpi_suspend_begin,
 303         .prepare_late = acpi_pm_prepare,
 304         .enter = acpi_suspend_enter,
 305         .wake = acpi_pm_finish,
 306         .end = acpi_pm_end,
 307 };
 308
 309 /**
 310  *      acpi_suspend_begin_old - Set the target system sleep state to the
 311  *              state associated with given @pm_state, if supported, and
 312  *              execute the _PTS control method.  This function is used if the
 313  *              pre-ACPI 2.0 suspend ordering has been requested.
 314  */
 315 static int acpi_suspend_begin_old(suspend_state_t pm_state)
 316 {
 317         int error = acpi_suspend_begin(pm_state);
 318
 319         if (!error)
 320                 error = __acpi_pm_prepare();
 321         return error;
 322 }
 323
 324 /*
 325  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 326  * been requested.
 327  */
 328 static struct platform_suspend_ops acpi_suspend_ops_old = {
 329         .valid = acpi_suspend_state_valid,
 330         .begin = acpi_suspend_begin_old,
 331         .prepare_late = acpi_pm_disable_gpes,
 332         .enter = acpi_suspend_enter,
 333         .wake = acpi_pm_finish,
 334         .end = acpi_pm_end,
 335         .recover = acpi_pm_finish,
 336 };
 337
 338 static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
 339 {
 340         old_suspend_ordering = true;
 341         return 0;
 342 }
 343
 344 static int __init init_set_sci_en_on_resume(const struct dmi_system_id *d)
 345 {
 346         set_sci_en_on_resume = true;
 347         return 0;
 348 }
 349
 350 static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 351         {
 352         .callback = init_old_suspend_ordering,
 353         .ident = "Abit KN9 (nForce4 variant)",
 354         .matches = {
 355                 DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
 356                 DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
 357                 },
 358         },
 359         {
 360         .callback = init_old_suspend_ordering,
 361         .ident = "HP xw4600 Workstation",
 362         .matches = {
 363                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 364                 DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
 365                 },
 366         },
 367         {
 368         .callback = init_set_sci_en_on_resume,
 369         .ident = "Apple MacBook 1,1",
 370         .matches = {
 371                 DMI_MATCH(DMI_SYS_VENDOR, "Apple Computer, Inc."),
 372                 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook1,1"),
 373                 },
 374         },
 375         {
 376         .callback = init_set_sci_en_on_resume,
 377         .ident = "Apple MacMini 1,1",
 378         .matches = {
 379                 DMI_MATCH(DMI_SYS_VENDOR, "Apple Computer, Inc."),
 380                 DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
 381                 },
 382         },
 383         {
 384         .callback = init_old_suspend_ordering,
 385         .ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
 386         .matches = {
 387                 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTek Computer INC."),
 388                 DMI_MATCH(DMI_BOARD_NAME, "M2N8L"),
 389                 },
 390         },
 391         {
 392         .callback = init_set_sci_en_on_resume,
 393         .ident = "Toshiba Satellite L300",
 394         .matches = {
 395                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 396                 DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
 397                 },
 398         },
 399         {
 400         .callback = init_set_sci_en_on_resume,
 401         .ident = "Hewlett-Packard HP G7000 Notebook PC",
 402         .matches = {
 403                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 404                 DMI_MATCH(DMI_PRODUCT_NAME, "HP G7000 Notebook PC"),
 405                 },
 406         },
 407         {
 408         .callback = init_set_sci_en_on_resume,
 409         .ident = "Hewlett-Packard HP Pavilion dv3 Notebook PC",
 410         .matches = {
 411                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 412                 DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv3 Notebook PC"),
 413                 },
 414         },
 415         {
 416         .callback = init_set_sci_en_on_resume,
 417         .ident = "Hewlett-Packard Pavilion dv4",
 418         .matches = {
 419                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 420                 DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv4"),
 421                 },
 422         },
 423         {
 424         .callback = init_set_sci_en_on_resume,
 425         .ident = "Hewlett-Packard Pavilion dv7",
 426         .matches = {
 427                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 428                 DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv7"),
 429                 },
 430         },
 431         {
 432         .callback = init_set_sci_en_on_resume,
 433         .ident = "Hewlett-Packard Compaq Presario C700 Notebook PC",
 434         .matches = {
 435                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 436                 DMI_MATCH(DMI_PRODUCT_NAME, "Compaq Presario C700 Notebook PC"),
 437                 },
 438         },
 439         {
 440         .callback = init_set_sci_en_on_resume,
 441         .ident = "Hewlett-Packard Compaq Presario CQ40 Notebook PC",
 442         .matches = {
 443                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 444                 DMI_MATCH(DMI_PRODUCT_NAME, "Compaq Presario CQ40 Notebook PC"),
 445                 },
 446         },
 447         {
 448         .callback = init_old_suspend_ordering,
 449         .ident = "Panasonic CF51-2L",
 450         .matches = {
 451                 DMI_MATCH(DMI_BOARD_VENDOR,
 452                                 "Matsushita Electric Industrial Co.,Ltd."),
 453                 DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
 454                 },
 455         },
 456         {},
 457 };
 458 #endif /* CONFIG_SUSPEND */
 459
 460 #ifdef CONFIG_HIBERNATION
 461 /*
 462  * The ACPI specification wants us to save NVS memory regions during hibernation
 463  * and to restore them during the subsequent resume.  However, it is not certain
 464  * if this mechanism is going to work on all machines, so we allow the user to
 465  * disable this mechanism using the 'acpi_sleep=s4_nonvs' kernel command line
 466  * option.
 467  */
 468 static bool s4_no_nvs;
 469
 470 void __init acpi_s4_no_nvs(void)
 471 {
 472         s4_no_nvs = true;
 473 }
 474
 475 static unsigned long s4_hardware_signature;
 476 static struct acpi_table_facs *facs;
 477 static bool nosigcheck;
 478
 479 void __init acpi_no_s4_hw_signature(void)
 480 {
 481         nosigcheck = true;
 482 }
 483
 484 static int acpi_hibernation_begin(void)
 485 {
 486         int error;
 487
 488         error = s4_no_nvs ? 0 : hibernate_nvs_alloc();
 489         if (!error) {
 490                 acpi_target_sleep_state = ACPI_STATE_S4;
 491                 acpi_sleep_tts_switch(acpi_target_sleep_state);
 492         }
 493
 494         return error;
 495 }
 496
 497 static int acpi_hibernation_pre_snapshot(void)
 498 {
 499         int error = acpi_pm_prepare();
 500
 501         if (!error)
 502                 hibernate_nvs_save();
 503
 504         return error;
 505 }
 506
 507 static int acpi_hibernation_enter(void)
 508 {
 509         acpi_status status = AE_OK;
 510         unsigned long flags = 0;
 511
 512         ACPI_FLUSH_CPU_CACHE();
 513
 514         local_irq_save(flags);
 515         acpi_enable_wakeup_device(ACPI_STATE_S4);
 516         /* This shouldn't return.  If it returns, we have a problem */
 517         status = acpi_enter_sleep_state(ACPI_STATE_S4);
 518         /* Reprogram control registers and execute _BFS */
 519         acpi_leave_sleep_state_prep(ACPI_STATE_S4);
 520         local_irq_restore(flags);
 521
 522         return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 523 }
 524
 525 static void acpi_hibernation_finish(void)
 526 {
 527         hibernate_nvs_free();
 528         acpi_pm_finish();
 529 }
 530
 531 static void acpi_hibernation_leave(void)
 532 {
 533         /*
 534          * If ACPI is not enabled by the BIOS and the boot kernel, we need to
 535          * enable it here.
 536          */
 537         acpi_enable();
 538         /* Reprogram control registers and execute _BFS */
 539         acpi_leave_sleep_state_prep(ACPI_STATE_S4);
 540         /* Check the hardware signature */
 541         if (facs && s4_hardware_signature != facs->hardware_signature) {
 542                 printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
 543                         "cannot resume!\n");
 544                 panic("ACPI S4 hardware signature mismatch");
 545         }
 546         /* Restore the NVS memory area */
 547         hibernate_nvs_restore();
 548 }
 549
 550 static void acpi_pm_enable_gpes(void)
 551 {
 552         acpi_enable_all_runtime_gpes();
 553 }
 554
 555 static struct platform_hibernation_ops acpi_hibernation_ops = {
 556         .begin = acpi_hibernation_begin,
 557         .end = acpi_pm_end,
 558         .pre_snapshot = acpi_hibernation_pre_snapshot,
 559         .finish = acpi_hibernation_finish,
 560         .prepare = acpi_pm_prepare,
 561         .enter = acpi_hibernation_enter,
 562         .leave = acpi_hibernation_leave,
 563         .pre_restore = acpi_pm_disable_gpes,
 564         .restore_cleanup = acpi_pm_enable_gpes,
 565 };
 566
 567 /**
 568  *      acpi_hibernation_begin_old - Set the target system sleep state to
 569  *              ACPI_STATE_S4 and execute the _PTS control method.  This
 570  *              function is used if the pre-ACPI 2.0 suspend ordering has been
 571  *              requested.
 572  */
 573 static int acpi_hibernation_begin_old(void)
 574 {
 575         int error;
 576         /*
 577          * The _TTS object should always be evaluated before the _PTS object.
 578          * When the old_suspended_ordering is true, the _PTS object is
 579          * evaluated in the acpi_sleep_prepare.
 580          */
 581         acpi_sleep_tts_switch(ACPI_STATE_S4);
 582
 583         error = acpi_sleep_prepare(ACPI_STATE_S4);
 584
 585         if (!error) {
 586                 if (!s4_no_nvs)
 587                         error = hibernate_nvs_alloc();
 588                 if (!error)
 589                         acpi_target_sleep_state = ACPI_STATE_S4;
 590         }
 591         return error;
 592 }
 593
 594 static int acpi_hibernation_pre_snapshot_old(void)
 595 {
 596         int error = acpi_pm_disable_gpes();
 597
 598         if (!error)
 599                 hibernate_nvs_save();
 600
 601         return error;
 602 }
 603
 604 /*
 605  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 606  * been requested.
 607  */
 608 static struct platform_hibernation_ops acpi_hibernation_ops_old = {
 609         .begin = acpi_hibernation_begin_old,
 610         .end = acpi_pm_end,
 611         .pre_snapshot = acpi_hibernation_pre_snapshot_old,
 612         .finish = acpi_hibernation_finish,
 613         .prepare = acpi_pm_disable_gpes,
 614         .enter = acpi_hibernation_enter,
 615         .leave = acpi_hibernation_leave,
 616         .pre_restore = acpi_pm_disable_gpes,
 617         .restore_cleanup = acpi_pm_enable_gpes,
 618         .recover = acpi_pm_finish,
 619 };
 620 #endif /* CONFIG_HIBERNATION */
 621
 622 int acpi_suspend(u32 acpi_state)
 623 {
 624         suspend_state_t states[] = {
 625                 [1] = PM_SUSPEND_STANDBY,
 626                 [3] = PM_SUSPEND_MEM,
 627                 [5] = PM_SUSPEND_MAX
 628         };
 629
 630         if (acpi_state < 6 && states[acpi_state])
 631                 return pm_suspend(states[acpi_state]);
 632         if (acpi_state == 4)
 633                 return hibernate();
 634         return -EINVAL;
 635 }
 636
 637 #ifdef CONFIG_PM_SLEEP
 638 /**
 639  *      acpi_pm_device_sleep_state - return preferred power state of ACPI device
 640  *              in the system sleep state given by %acpi_target_sleep_state
 641  *      @dev: device to examine; its driver model wakeup flags control
 642  *              whether it should be able to wake up the system
 643  *      @d_min_p: used to store the upper limit of allowed states range
 644  *      Return value: preferred power state of the device on success, -ENODEV on
 645  *              failure (ie. if there's no 'struct acpi_device' for @dev)
 646  *
 647  *      Find the lowest power (highest number) ACPI device power state that
 648  *      device @dev can be in while the system is in the sleep state represented
 649  *      by %acpi_target_sleep_state.  If @wake is nonzero, the device should be
 650  *      able to wake up the system from this sleep state.  If @d_min_p is set,
 651  *      the highest power (lowest number) device power state of @dev allowed
 652  *      in this system sleep state is stored at the location pointed to by it.
 653  *
 654  *      The caller must ensure that @dev is valid before using this function.
 655  *      The caller is also responsible for figuring out if the device is
 656  *      supposed to be able to wake up the system and passing this information
 657  *      via @wake.
 658  */
 659
 660 int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p)
 661 {
 662         acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
 663         struct acpi_device *adev;
 664         char acpi_method[] = "_SxD";
 665         unsigned long long d_min, d_max;
 666
 667         if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
 668                 printk(KERN_DEBUG "ACPI handle has no context!\n");
 669                 return -ENODEV;
 670         }
 671
 672         acpi_method[2] = '0' + acpi_target_sleep_state;
 673         /*
 674          * If the sleep state is S0, we will return D3, but if the device has
 675          * _S0W, we will use the value from _S0W
 676          */
 677         d_min = ACPI_STATE_D0;
 678         d_max = ACPI_STATE_D3;
 679
 680         /*
 681          * If present, _SxD methods return the minimum D-state (highest power
 682          * state) we can use for the corresponding S-states.  Otherwise, the
 683          * minimum D-state is D0 (ACPI 3.x).
 684          *
 685          * NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
 686          * provided -- that's our fault recovery, we ignore retval.
 687          */
 688         if (acpi_target_sleep_state > ACPI_STATE_S0)
 689                 acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);
 690
 691         /*
 692          * If _PRW says we can wake up the system from the target sleep state,
 693          * the D-state returned by _SxD is sufficient for that (we assume a
 694          * wakeup-aware driver if wake is set).  Still, if _SxW exists
 695          * (ACPI 3.x), it should return the maximum (lowest power) D-state that
 696          * can wake the system.  _S0W may be valid, too.
 697          */
 698         if (acpi_target_sleep_state == ACPI_STATE_S0 ||
 699             (device_may_wakeup(dev) && adev->wakeup.state.enabled &&
 700              adev->wakeup.sleep_state <= acpi_target_sleep_state)) {
 701                 acpi_status status;
 702
 703                 acpi_method[3] = 'W';
 704                 status = acpi_evaluate_integer(handle, acpi_method, NULL,
 705                                                 &d_max);
 706                 if (ACPI_FAILURE(status)) {
 707                         d_max = d_min;
 708                 } else if (d_max < d_min) {
 709                         /* Warn the user of the broken DSDT */
 710                         printk(KERN_WARNING "ACPI: Wrong value from %s\n",
 711                                 acpi_method);
 712                         /* Sanitize it */
 713                         d_min = d_max;
 714                 }
 715         }
 716
 717         if (d_min_p)
 718                 *d_min_p = d_min;
 719         return d_max;
 720 }
 721
 722 /**
 723  *      acpi_pm_device_sleep_wake - enable or disable the system wake-up
 724  *                                  capability of given device
 725  *      @dev: device to handle
 726  *      @enable: 'true' - enable, 'false' - disable the wake-up capability
 727  */
 728 int acpi_pm_device_sleep_wake(struct device *dev, bool enable)
 729 {
 730         acpi_handle handle;
 731         struct acpi_device *adev;
 732         int error;
 733
 734         if (!device_can_wakeup(dev))
 735                 return -EINVAL;
 736
 737         handle = DEVICE_ACPI_HANDLE(dev);
 738         if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
 739                 dev_dbg(dev, "ACPI handle has no context in %s!\n", __func__);
 740                 return -ENODEV;
 741         }
 742
 743         error = enable ?
 744                 acpi_enable_wakeup_device_power(adev, acpi_target_sleep_state) :
 745                 acpi_disable_wakeup_device_power(adev);
 746         if (!error)
 747                 dev_info(dev, "wake-up capability %s by ACPI\n",
 748                                 enable ? "enabled" : "disabled");
 749
 750         return error;
 751 }
 752 #endif
 753
 754 static void acpi_power_off_prepare(void)
 755 {
 756         /* Prepare to power off the system */
 757         acpi_sleep_prepare(ACPI_STATE_S5);
 758         acpi_disable_all_gpes();
 759 }
 760
 761 static void acpi_power_off(void)
 762 {
 763         /* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 764         printk(KERN_DEBUG "%s called\n", __func__);
 765         local_irq_disable();
 766         acpi_enable_wakeup_device(ACPI_STATE_S5);
 767         acpi_enter_sleep_state(ACPI_STATE_S5);
 768 }
 769
 770 /*
 771  * ACPI 2.0 created the optional _GTS and _BFS,
 772  * but industry adoption has been neither rapid nor broad.
 773  *
 774  * Linux gets into trouble when it executes poorly validated
 775  * paths through the BIOS, so disable _GTS and _BFS by default,
 776  * but do speak up and offer the option to enable them.
 777  */
 778 void __init acpi_gts_bfs_check(void)
 779 {
 780         acpi_handle dummy;
 781
 782         if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__GTS, &dummy)))
 783         {
 784                 printk(KERN_NOTICE PREFIX "BIOS offers _GTS\n");
 785                 printk(KERN_NOTICE PREFIX "If \"acpi.gts=1\" improves suspend, "
 786                         "please notify linux-acpi@vger.kernel.org\n");
 787         }
 788         if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__BFS, &dummy)))
 789         {
 790                 printk(KERN_NOTICE PREFIX "BIOS offers _BFS\n");
 791                 printk(KERN_NOTICE PREFIX "If \"acpi.bfs=1\" improves resume, "
 792                         "please notify linux-acpi@vger.kernel.org\n");
 793         }
 794 }
 795
 796 int __init acpi_sleep_init(void)
 797 {
 798         acpi_status status;
 799         u8 type_a, type_b;
 800 #ifdef CONFIG_SUSPEND
 801         int i = 0;
 802
 803         dmi_check_system(acpisleep_dmi_table);
 804 #endif
 805
 806         if (acpi_disabled)
 807                 return 0;
 808
 809         sleep_states[ACPI_STATE_S0] = 1;
 810         printk(KERN_INFO PREFIX "(supports S0");
 811
 812 #ifdef CONFIG_SUSPEND
 813         for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++) {
 814                 status = acpi_get_sleep_type_data(i, &type_a, &type_b);
 815                 if (ACPI_SUCCESS(status)) {
 816                         sleep_states[i] = 1;
 817                         printk(" S%d", i);
 818                 }
 819         }
 820
 821         suspend_set_ops(old_suspend_ordering ?
 822                 &acpi_suspend_ops_old : &acpi_suspend_ops);
 823 #endif
 824
 825 #ifdef CONFIG_HIBERNATION
 826         status = acpi_get_sleep_type_data(ACPI_STATE_S4, &type_a, &type_b);
 827         if (ACPI_SUCCESS(status)) {
 828                 hibernation_set_ops(old_suspend_ordering ?
 829                         &acpi_hibernation_ops_old : &acpi_hibernation_ops);
 830                 sleep_states[ACPI_STATE_S4] = 1;
 831                 printk(" S4");
 832                 if (!nosigcheck) {
 833                         acpi_get_table(ACPI_SIG_FACS, 1,
 834                                 (struct acpi_table_header **)&facs);
 835                         if (facs)
 836                                 s4_hardware_signature =
 837                                         facs->hardware_signature;
 838                 }
 839         }
 840 #endif
 841         status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
 842         if (ACPI_SUCCESS(status)) {
 843                 sleep_states[ACPI_STATE_S5] = 1;
 844                 printk(" S5");
 845                 pm_power_off_prepare = acpi_power_off_prepare;
 846                 pm_power_off = acpi_power_off;
 847         }
 848         printk(")\n");
 849         /*
 850          * Register the tts_notifier to reboot notifier list so that the _TTS
 851          * object can also be evaluated when the system enters S5.
 852          */
 853         register_reboot_notifier(&tts_notifier);
 854         acpi_gts_bfs_check();
 855         return 0;
 856 }