drivers/acpi/bus.c

   1 /*
   2  *  acpi_bus.c - ACPI Bus Driver ($Revision: 80 $)
   3  *
   4  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   5  *
   6  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or (at
  11  *  your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful, but
  14  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *  General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License along
  19  *  with this program; if not, write to the Free Software Foundation, Inc.,
  20  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  21  *
  22  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/ioport.h>
  28 #include <linux/kernel.h>
  29 #include <linux/list.h>
  30 #include <linux/sched.h>
  31 #include <linux/pm.h>
  32 #include <linux/device.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/acpi.h>
  35 #include <linux/slab.h>
  36 #include <linux/regulator/machine.h>
  37 #ifdef CONFIG_X86
  38 #include <asm/mpspec.h>
  39 #endif
  40 #include <linux/pci.h>
  41 #include <acpi/apei.h>
  42 #include <linux/dmi.h>
  43 #include <linux/suspend.h>
  44
  45 #include "internal.h"
  46
  47 #define _COMPONENT              ACPI_BUS_COMPONENT
  48 ACPI_MODULE_NAME("bus");
  49
  50 struct acpi_device *acpi_root;
  51 struct proc_dir_entry *acpi_root_dir;
  52 EXPORT_SYMBOL(acpi_root_dir);
  53
  54 #ifdef CONFIG_X86
  55 #ifdef CONFIG_ACPI_CUSTOM_DSDT
  56 static inline int set_copy_dsdt(const struct dmi_system_id *id)
  57 {
  58         return 0;
  59 }
  60 #else
  61 static int set_copy_dsdt(const struct dmi_system_id *id)
  62 {
  63         printk(KERN_NOTICE "%s detected - "
  64                 "force copy of DSDT to local memory\n", id->ident);
  65         acpi_gbl_copy_dsdt_locally = 1;
  66         return 0;
  67 }
  68 #endif
  69
  70 static struct dmi_system_id dsdt_dmi_table[] __initdata = {
  71         /*
  72          * Invoke DSDT corruption work-around on all Toshiba Satellite.
  73          * https://bugzilla.kernel.org/show_bug.cgi?id=14679
  74          */
  75         {
  76          .callback = set_copy_dsdt,
  77          .ident = "TOSHIBA Satellite",
  78          .matches = {
  79                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
  80                 DMI_MATCH(DMI_PRODUCT_NAME, "Satellite"),
  81                 },
  82         },
  83         {}
  84 };
  85 #else
  86 static struct dmi_system_id dsdt_dmi_table[] __initdata = {
  87         {}
  88 };
  89 #endif
  90
  91 /* --------------------------------------------------------------------------
  92                                 Device Management
  93    -------------------------------------------------------------------------- */
  94
  95 acpi_status acpi_bus_get_status_handle(acpi_handle handle,
  96                                        unsigned long long *sta)
  97 {
  98         acpi_status status;
  99
 100         status = acpi_evaluate_integer(handle, "_STA", NULL, sta);
 101         if (ACPI_SUCCESS(status))
 102                 return AE_OK;
 103
 104         if (status == AE_NOT_FOUND) {
 105                 *sta = ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
 106                        ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
 107                 return AE_OK;
 108         }
 109         return status;
 110 }
 111
 112 int acpi_bus_get_status(struct acpi_device *device)
 113 {
 114         acpi_status status;
 115         unsigned long long sta;
 116
 117         status = acpi_bus_get_status_handle(device->handle, &sta);
 118         if (ACPI_FAILURE(status))
 119                 return -ENODEV;
 120
 121         acpi_set_device_status(device, sta);
 122
 123         if (device->status.functional && !device->status.present) {
 124                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: "
 125                        "functional but not present;\n",
 126                         device->pnp.bus_id, (u32)sta));
 127         }
 128
 129         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
 130                           device->pnp.bus_id, (u32)sta));
 131         return 0;
 132 }
 133 EXPORT_SYMBOL(acpi_bus_get_status);
 134
 135 void acpi_bus_private_data_handler(acpi_handle handle,
 136                                    void *context)
 137 {
 138         return;
 139 }
 140 EXPORT_SYMBOL(acpi_bus_private_data_handler);
 141
 142 int acpi_bus_attach_private_data(acpi_handle handle, void *data)
 143 {
 144         acpi_status status;
 145
 146         status = acpi_attach_data(handle,
 147                         acpi_bus_private_data_handler, data);
 148         if (ACPI_FAILURE(status)) {
 149                 acpi_handle_debug(handle, "Error attaching device data\n");
 150                 return -ENODEV;
 151         }
 152
 153         return 0;
 154 }
 155 EXPORT_SYMBOL_GPL(acpi_bus_attach_private_data);
 156
 157 int acpi_bus_get_private_data(acpi_handle handle, void **data)
 158 {
 159         acpi_status status;
 160
 161         if (!*data)
 162                 return -EINVAL;
 163
 164         status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
 165         if (ACPI_FAILURE(status)) {
 166                 acpi_handle_debug(handle, "No context for object\n");
 167                 return -ENODEV;
 168         }
 169
 170         return 0;
 171 }
 172 EXPORT_SYMBOL_GPL(acpi_bus_get_private_data);
 173
 174 void acpi_bus_detach_private_data(acpi_handle handle)
 175 {
 176         acpi_detach_data(handle, acpi_bus_private_data_handler);
 177 }
 178 EXPORT_SYMBOL_GPL(acpi_bus_detach_private_data);
 179
 180 void acpi_bus_no_hotplug(acpi_handle handle)
 181 {
 182         struct acpi_device *adev = NULL;
 183
 184         acpi_bus_get_device(handle, &adev);
 185         if (adev)
 186                 adev->flags.no_hotplug = true;
 187 }
 188 EXPORT_SYMBOL_GPL(acpi_bus_no_hotplug);
 189
 190 static void acpi_print_osc_error(acpi_handle handle,
 191         struct acpi_osc_context *context, char *error)
 192 {
 193         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER};
 194         int i;
 195
 196         if (ACPI_FAILURE(acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer)))
 197                 printk(KERN_DEBUG "%s\n", error);
 198         else {
 199                 printk(KERN_DEBUG "%s:%s\n", (char *)buffer.pointer, error);
 200                 kfree(buffer.pointer);
 201         }
 202         printk(KERN_DEBUG"_OSC request data:");
 203         for (i = 0; i < context->cap.length; i += sizeof(u32))
 204                 printk("%x ", *((u32 *)(context->cap.pointer + i)));
 205         printk("\n");
 206 }
 207
 208 acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
 209 {
 210         int i;
 211         static int opc_map_to_uuid[16] = {6, 4, 2, 0, 11, 9, 16, 14, 19, 21,
 212                 24, 26, 28, 30, 32, 34};
 213
 214         if (strlen(str) != 36)
 215                 return AE_BAD_PARAMETER;
 216         for (i = 0; i < 36; i++) {
 217                 if (i == 8 || i == 13 || i == 18 || i == 23) {
 218                         if (str[i] != '-')
 219                                 return AE_BAD_PARAMETER;
 220                 } else if (!isxdigit(str[i]))
 221                         return AE_BAD_PARAMETER;
 222         }
 223         for (i = 0; i < 16; i++) {
 224                 uuid[i] = hex_to_bin(str[opc_map_to_uuid[i]]) << 4;
 225                 uuid[i] |= hex_to_bin(str[opc_map_to_uuid[i] + 1]);
 226         }
 227         return AE_OK;
 228 }
 229 EXPORT_SYMBOL_GPL(acpi_str_to_uuid);
 230
 231 acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
 232 {
 233         acpi_status status;
 234         struct acpi_object_list input;
 235         union acpi_object in_params[4];
 236         union acpi_object *out_obj;
 237         u8 uuid[16];
 238         u32 errors;
 239         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 240
 241         if (!context)
 242                 return AE_ERROR;
 243         if (ACPI_FAILURE(acpi_str_to_uuid(context->uuid_str, uuid)))
 244                 return AE_ERROR;
 245         context->ret.length = ACPI_ALLOCATE_BUFFER;
 246         context->ret.pointer = NULL;
 247
 248         /* Setting up input parameters */
 249         input.count = 4;
 250         input.pointer = in_params;
 251         in_params[0].type               = ACPI_TYPE_BUFFER;
 252         in_params[0].buffer.length      = 16;
 253         in_params[0].buffer.pointer     = uuid;
 254         in_params[1].type               = ACPI_TYPE_INTEGER;
 255         in_params[1].integer.value      = context->rev;
 256         in_params[2].type               = ACPI_TYPE_INTEGER;
 257         in_params[2].integer.value      = context->cap.length/sizeof(u32);
 258         in_params[3].type               = ACPI_TYPE_BUFFER;
 259         in_params[3].buffer.length      = context->cap.length;
 260         in_params[3].buffer.pointer     = context->cap.pointer;
 261
 262         status = acpi_evaluate_object(handle, "_OSC", &input, &output);
 263         if (ACPI_FAILURE(status))
 264                 return status;
 265
 266         if (!output.length)
 267                 return AE_NULL_OBJECT;
 268
 269         out_obj = output.pointer;
 270         if (out_obj->type != ACPI_TYPE_BUFFER
 271                 || out_obj->buffer.length != context->cap.length) {
 272                 acpi_print_osc_error(handle, context,
 273                         "_OSC evaluation returned wrong type");
 274                 status = AE_TYPE;
 275                 goto out_kfree;
 276         }
 277         /* Need to ignore the bit0 in result code */
 278         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 279         if (errors) {
 280                 if (errors & OSC_REQUEST_ERROR)
 281                         acpi_print_osc_error(handle, context,
 282                                 "_OSC request failed");
 283                 if (errors & OSC_INVALID_UUID_ERROR)
 284                         acpi_print_osc_error(handle, context,
 285                                 "_OSC invalid UUID");
 286                 if (errors & OSC_INVALID_REVISION_ERROR)
 287                         acpi_print_osc_error(handle, context,
 288                                 "_OSC invalid revision");
 289                 if (errors & OSC_CAPABILITIES_MASK_ERROR) {
 290                         if (((u32 *)context->cap.pointer)[OSC_QUERY_DWORD]
 291                             & OSC_QUERY_ENABLE)
 292                                 goto out_success;
 293                         status = AE_SUPPORT;
 294                         goto out_kfree;
 295                 }
 296                 status = AE_ERROR;
 297                 goto out_kfree;
 298         }
 299 out_success:
 300         context->ret.length = out_obj->buffer.length;
 301         context->ret.pointer = kmemdup(out_obj->buffer.pointer,
 302                                        context->ret.length, GFP_KERNEL);
 303         if (!context->ret.pointer) {
 304                 status =  AE_NO_MEMORY;
 305                 goto out_kfree;
 306         }
 307         status =  AE_OK;
 308
 309 out_kfree:
 310         kfree(output.pointer);
 311         if (status != AE_OK)
 312                 context->ret.pointer = NULL;
 313         return status;
 314 }
 315 EXPORT_SYMBOL(acpi_run_osc);
 316
 317 bool osc_sb_apei_support_acked;
 318 static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
 319 static void acpi_bus_osc_support(void)
 320 {
 321         u32 capbuf[2];
 322         struct acpi_osc_context context = {
 323                 .uuid_str = sb_uuid_str,
 324                 .rev = 1,
 325                 .cap.length = 8,
 326                 .cap.pointer = capbuf,
 327         };
 328         acpi_handle handle;
 329
 330         capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;
 331         capbuf[OSC_SUPPORT_DWORD] = OSC_SB_PR3_SUPPORT; /* _PR3 is in use */
 332 #if defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) ||\
 333                         defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE)
 334         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PAD_SUPPORT;
 335 #endif
 336
 337 #if defined(CONFIG_ACPI_PROCESSOR) || defined(CONFIG_ACPI_PROCESSOR_MODULE)
 338         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PPC_OST_SUPPORT;
 339 #endif
 340
 341         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
 342
 343         if (!ghes_disable)
 344                 capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
 345         if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
 346                 return;
 347         if (ACPI_SUCCESS(acpi_run_osc(handle, &context))) {
 348                 u32 *capbuf_ret = context.ret.pointer;
 349                 if (context.ret.length > OSC_SUPPORT_DWORD)
 350                         osc_sb_apei_support_acked =
 351                                 capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
 352                 kfree(context.ret.pointer);
 353         }
 354         /* do we need to check other returned cap? Sounds no */
 355 }
 356
 357 /* --------------------------------------------------------------------------
 358                              Notification Handling
 359    -------------------------------------------------------------------------- */
 360
 361 /**
 362  * acpi_bus_notify
 363  * ---------------
 364  * Callback for all 'system-level' device notifications (values 0x00-0x7F).
 365  */
 366 static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
 367 {
 368         struct acpi_device *adev;
 369         struct acpi_driver *driver;
 370         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
 371         bool hotplug_event = false;
 372
 373         switch (type) {
 374         case ACPI_NOTIFY_BUS_CHECK:
 375                 acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
 376                 hotplug_event = true;
 377                 break;
 378
 379         case ACPI_NOTIFY_DEVICE_CHECK:
 380                 acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_CHECK event\n");
 381                 hotplug_event = true;
 382                 break;
 383
 384         case ACPI_NOTIFY_DEVICE_WAKE:
 385                 acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_WAKE event\n");
 386                 break;
 387
 388         case ACPI_NOTIFY_EJECT_REQUEST:
 389                 acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
 390                 hotplug_event = true;
 391                 break;
 392
 393         case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
 394                 acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_CHECK_LIGHT event\n");
 395                 /* TBD: Exactly what does 'light' mean? */
 396                 break;
 397
 398         case ACPI_NOTIFY_FREQUENCY_MISMATCH:
 399                 acpi_handle_err(handle, "Device cannot be configured due "
 400                                 "to a frequency mismatch\n");
 401                 break;
 402
 403         case ACPI_NOTIFY_BUS_MODE_MISMATCH:
 404                 acpi_handle_err(handle, "Device cannot be configured due "
 405                                 "to a bus mode mismatch\n");
 406                 break;
 407
 408         case ACPI_NOTIFY_POWER_FAULT:
 409                 acpi_handle_err(handle, "Device has suffered a power fault\n");
 410                 break;
 411
 412         default:
 413                 acpi_handle_debug(handle, "Unknown event type 0x%x\n", type);
 414                 break;
 415         }
 416
 417         adev = acpi_bus_get_acpi_device(handle);
 418         if (!adev)
 419                 goto err;
 420
 421         driver = adev->driver;
 422         if (driver && driver->ops.notify &&
 423             (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
 424                 driver->ops.notify(adev, type);
 425
 426         if (hotplug_event && ACPI_SUCCESS(acpi_hotplug_schedule(adev, type)))
 427                 return;
 428
 429         acpi_bus_put_acpi_device(adev);
 430         return;
 431
 432  err:
 433         acpi_evaluate_ost(handle, type, ost_code, NULL);
 434 }
 435
 436 /* --------------------------------------------------------------------------
 437                              Initialization/Cleanup
 438    -------------------------------------------------------------------------- */
 439
 440 static int __init acpi_bus_init_irq(void)
 441 {
 442         acpi_status status;
 443         char *message = NULL;
 444
 445
 446         /*
 447          * Let the system know what interrupt model we are using by
 448          * evaluating the \_PIC object, if exists.
 449          */
 450
 451         switch (acpi_irq_model) {
 452         case ACPI_IRQ_MODEL_PIC:
 453                 message = "PIC";
 454                 break;
 455         case ACPI_IRQ_MODEL_IOAPIC:
 456                 message = "IOAPIC";
 457                 break;
 458         case ACPI_IRQ_MODEL_IOSAPIC:
 459                 message = "IOSAPIC";
 460                 break;
 461         case ACPI_IRQ_MODEL_PLATFORM:
 462                 message = "platform specific model";
 463                 break;
 464         default:
 465                 printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
 466                 return -ENODEV;
 467         }
 468
 469         printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);
 470
 471         status = acpi_execute_simple_method(NULL, "\\_PIC", acpi_irq_model);
 472         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 473                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PIC"));
 474                 return -ENODEV;
 475         }
 476
 477         return 0;
 478 }
 479
 480 u8 acpi_gbl_permanent_mmap;
 481
 482
 483 void __init acpi_early_init(void)
 484 {
 485         acpi_status status;
 486
 487         if (acpi_disabled)
 488                 return;
 489
 490         printk(KERN_INFO PREFIX "Core revision %08x\n", ACPI_CA_VERSION);
 491
 492         /* It's safe to verify table checksums during late stage */
 493         acpi_gbl_verify_table_checksum = TRUE;
 494
 495         /* enable workarounds, unless strict ACPI spec. compliance */
 496         if (!acpi_strict)
 497                 acpi_gbl_enable_interpreter_slack = TRUE;
 498
 499         acpi_gbl_permanent_mmap = 1;
 500
 501         /*
 502          * If the machine falls into the DMI check table,
 503          * DSDT will be copied to memory
 504          */
 505         dmi_check_system(dsdt_dmi_table);
 506
 507         status = acpi_reallocate_root_table();
 508         if (ACPI_FAILURE(status)) {
 509                 printk(KERN_ERR PREFIX
 510                        "Unable to reallocate ACPI tables\n");
 511                 goto error0;
 512         }
 513
 514         status = acpi_initialize_subsystem();
 515         if (ACPI_FAILURE(status)) {
 516                 printk(KERN_ERR PREFIX
 517                        "Unable to initialize the ACPI Interpreter\n");
 518                 goto error0;
 519         }
 520
 521         status = acpi_load_tables();
 522         if (ACPI_FAILURE(status)) {
 523                 printk(KERN_ERR PREFIX
 524                        "Unable to load the System Description Tables\n");
 525                 goto error0;
 526         }
 527
 528 #ifdef CONFIG_X86
 529         if (!acpi_ioapic) {
 530                 /* compatible (0) means level (3) */
 531                 if (!(acpi_sci_flags & ACPI_MADT_TRIGGER_MASK)) {
 532                         acpi_sci_flags &= ~ACPI_MADT_TRIGGER_MASK;
 533                         acpi_sci_flags |= ACPI_MADT_TRIGGER_LEVEL;
 534                 }
 535                 /* Set PIC-mode SCI trigger type */
 536                 acpi_pic_sci_set_trigger(acpi_gbl_FADT.sci_interrupt,
 537                                          (acpi_sci_flags & ACPI_MADT_TRIGGER_MASK) >> 2);
 538         } else {
 539                 /*
 540                  * now that acpi_gbl_FADT is initialized,
 541                  * update it with result from INT_SRC_OVR parsing
 542                  */
 543                 acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
 544         }
 545 #endif
 546
 547         status = acpi_enable_subsystem(~ACPI_NO_ACPI_ENABLE);
 548         if (ACPI_FAILURE(status)) {
 549                 printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
 550                 goto error0;
 551         }
 552
 553         /*
 554          * If the system is using ACPI then we can be reasonably
 555          * confident that any regulators are managed by the firmware
 556          * so tell the regulator core it has everything it needs to
 557          * know.
 558          */
 559         regulator_has_full_constraints();
 560
 561         return;
 562
 563       error0:
 564         disable_acpi();
 565         return;
 566 }
 567
 568 static int __init acpi_bus_init(void)
 569 {
 570         int result;
 571         acpi_status status;
 572
 573         acpi_os_initialize1();
 574
 575         status = acpi_enable_subsystem(ACPI_NO_ACPI_ENABLE);
 576         if (ACPI_FAILURE(status)) {
 577                 printk(KERN_ERR PREFIX
 578                        "Unable to start the ACPI Interpreter\n");
 579                 goto error1;
 580         }
 581
 582         /*
 583          * ACPI 2.0 requires the EC driver to be loaded and work before
 584          * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
 585          * is called).
 586          *
 587          * This is accomplished by looking for the ECDT table, and getting
 588          * the EC parameters out of that.
 589          */
 590         status = acpi_ec_ecdt_probe();
 591         /* Ignore result. Not having an ECDT is not fatal. */
 592
 593         status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
 594         if (ACPI_FAILURE(status)) {
 595                 printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
 596                 goto error1;
 597         }
 598
 599         /*
 600          * _OSC method may exist in module level code,
 601          * so it must be run after ACPI_FULL_INITIALIZATION
 602          */
 603         acpi_bus_osc_support();
 604
 605         /*
 606          * _PDC control method may load dynamic SSDT tables,
 607          * and we need to install the table handler before that.
 608          */
 609         acpi_sysfs_init();
 610
 611         acpi_early_processor_set_pdc();
 612
 613         /*
 614          * Maybe EC region is required at bus_scan/acpi_get_devices. So it
 615          * is necessary to enable it as early as possible.
 616          */
 617         acpi_boot_ec_enable();
 618
 619         printk(KERN_INFO PREFIX "Interpreter enabled\n");
 620
 621         /* Initialize sleep structures */
 622         acpi_sleep_init();
 623
 624         /*
 625          * Get the system interrupt model and evaluate \_PIC.
 626          */
 627         result = acpi_bus_init_irq();
 628         if (result)
 629                 goto error1;
 630
 631         /*
 632          * Register the for all standard device notifications.
 633          */
 634         status =
 635             acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY,
 636                                         &acpi_bus_notify, NULL);
 637         if (ACPI_FAILURE(status)) {
 638                 printk(KERN_ERR PREFIX
 639                        "Unable to register for device notifications\n");
 640                 goto error1;
 641         }
 642
 643         /*
 644          * Create the top ACPI proc directory
 645          */
 646         acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);
 647
 648         return 0;
 649
 650         /* Mimic structured exception handling */
 651       error1:
 652         acpi_terminate();
 653         return -ENODEV;
 654 }
 655
 656 struct kobject *acpi_kobj;
 657 EXPORT_SYMBOL_GPL(acpi_kobj);
 658
 659 static int __init acpi_init(void)
 660 {
 661         int result;
 662
 663         if (acpi_disabled) {
 664                 printk(KERN_INFO PREFIX "Interpreter disabled.\n");
 665                 return -ENODEV;
 666         }
 667
 668         acpi_kobj = kobject_create_and_add("acpi", firmware_kobj);
 669         if (!acpi_kobj) {
 670                 printk(KERN_WARNING "%s: kset create error\n", __func__);
 671                 acpi_kobj = NULL;
 672         }
 673
 674         init_acpi_device_notify();
 675         result = acpi_bus_init();
 676         if (result) {
 677                 disable_acpi();
 678                 return result;
 679         }
 680
 681         pci_mmcfg_late_init();
 682         acpi_scan_init();
 683         acpi_ec_init();
 684         acpi_debugfs_init();
 685         acpi_sleep_proc_init();
 686         acpi_wakeup_device_init();
 687         return 0;
 688 }
 689
 690 subsys_initcall(acpi_init);