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/init.h>
  26 #include <linux/ioport.h>
  27 #include <linux/list.h>
  28 #include <linux/sched.h>
  29 #include <linux/pm.h>
  30 #include <linux/device.h>
  31 #include <linux/proc_fs.h>
  32 #ifdef CONFIG_X86
  33 #include <asm/mpspec.h>
  34 #endif
  35 #include "acpi_bus.h"
  36 #include "acpi_drivers.h"
  37
  38
  39 #define _COMPONENT              ACPI_BUS_COMPONENT
  40 ACPI_MODULE_NAME                ("acpi_bus")
  41
  42 extern void eisa_set_level_irq(unsigned int irq);
  43
  44 FADT_DESCRIPTOR                 acpi_fadt;
  45 struct acpi_device              *acpi_root;
  46 struct proc_dir_entry           *acpi_root_dir;
  47
  48 #define STRUCT_TO_INT(s)        (*((int*)&s))
  49
  50 /* --------------------------------------------------------------------------
  51                                 Device Management
  52    -------------------------------------------------------------------------- */
  53
  54 extern void acpi_bus_data_handler (
  55         acpi_handle             handle,
  56         u32                     function,
  57         void                    *context);
  58 int
  59 acpi_bus_get_device (
  60         acpi_handle             handle,
  61         struct acpi_device      **device)
  62 {
  63         acpi_status             status = AE_OK;
  64
  65         ACPI_FUNCTION_TRACE("acpi_bus_get_device");
  66
  67         if (!device)
  68                 return_VALUE(-EINVAL);
  69
  70         /* TBD: Support fixed-feature devices */
  71
  72         status = acpi_get_data(handle, acpi_bus_data_handler, (void**) device);
  73         if (ACPI_FAILURE(status) || !*device) {
  74                 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Error getting context for object [%p]\n",
  75                         handle));
  76                 return_VALUE(-ENODEV);
  77         }
  78
  79         return_VALUE(0);
  80 }
  81
  82 int
  83 acpi_bus_get_status (
  84         struct acpi_device      *device)
  85 {
  86         acpi_status             status = AE_OK;
  87         unsigned long           sta = 0;
  88
  89         ACPI_FUNCTION_TRACE("acpi_bus_get_status");
  90
  91         if (!device)
  92                 return_VALUE(-EINVAL);
  93
  94         /*
  95          * Evaluate _STA if present.
  96          */
  97         if (device->flags.dynamic_status) {
  98                 status = acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
  99                 if (ACPI_FAILURE(status))
 100                         return_VALUE(-ENODEV);
 101                 STRUCT_TO_INT(device->status) = (int) sta;
 102         }
 103
 104         /*
 105          * Otherwise we assume the status of our parent (unless we don't
 106          * have one, in which case status is implied).
 107          */
 108         else if (device->parent)
 109                 device->status = device->parent->status;
 110         else
 111                 STRUCT_TO_INT(device->status) = 0x0F;
 112
 113         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
 114                 device->pnp.bus_id, (u32) STRUCT_TO_INT(device->status)));
 115
 116         return_VALUE(0);
 117 }
 118
 119
 120 /* --------------------------------------------------------------------------
 121                                  Power Management
 122    -------------------------------------------------------------------------- */
 123
 124 int
 125 acpi_bus_get_power (
 126         acpi_handle             handle,
 127         int                     *state)
 128 {
 129         int                     result = 0;
 130         acpi_status             status = 0;
 131         struct acpi_device      *device = NULL;
 132         unsigned long           psc = 0;
 133
 134         ACPI_FUNCTION_TRACE("acpi_bus_get_power");
 135
 136         result = acpi_bus_get_device(handle, &device);
 137         if (result)
 138                 return_VALUE(result);
 139
 140         *state = ACPI_STATE_UNKNOWN;
 141
 142         if (!device->flags.power_manageable) {
 143                 /* TBD: Non-recursive algorithm for walking up hierarchy */
 144                 if (device->parent)
 145                         *state = device->parent->power.state;
 146                 else
 147                         *state = ACPI_STATE_D0;
 148         }
 149         else {
 150                 /*
 151                  * Get the device's power state either directly (via _PSC) or
 152                  * indirectly (via power resources).
 153                  */
 154                 if (device->power.flags.explicit_get) {
 155                         status = acpi_evaluate_integer(device->handle, "_PSC",
 156                                 NULL, &psc);
 157                         if (ACPI_FAILURE(status))
 158                                 return_VALUE(-ENODEV);
 159                         device->power.state = (int) psc;
 160                 }
 161                 else if (device->power.flags.power_resources) {
 162                         result = acpi_power_get_inferred_state(device);
 163                         if (result)
 164                                 return_VALUE(result);
 165                 }
 166
 167                 *state = device->power.state;
 168         }
 169
 170         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n",
 171                 device->pnp.bus_id, device->power.state));
 172
 173         return_VALUE(0);
 174 }
 175
 176
 177 int
 178 acpi_bus_set_power (
 179         acpi_handle             handle,
 180         int                     state)
 181 {
 182         int                     result = 0;
 183         acpi_status             status = AE_OK;
 184         struct acpi_device      *device = NULL;
 185         char                    object_name[5] = {'_','P','S','0'+state,'\0'};
 186
 187         ACPI_FUNCTION_TRACE("acpi_bus_set_power");
 188
 189         result = acpi_bus_get_device(handle, &device);
 190         if (result)
 191                 return_VALUE(result);
 192
 193         if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
 194                 return_VALUE(-EINVAL);
 195
 196         /* Make sure this is a valid target state */
 197
 198         if (!device->flags.power_manageable) {
 199                 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Device is not power manageable\n"));
 200                 return_VALUE(-ENODEV);
 201         }
 202         if (state == device->power.state) {
 203                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n", state));
 204                 return_VALUE(0);
 205         }
 206         if (!device->power.states[state].flags.valid) {
 207                 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Device does not support D%d\n", state));
 208                 return_VALUE(-ENODEV);
 209         }
 210         if (device->parent && (state < device->parent->power.state)) {
 211                 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Cannot set device to a higher-powered state than parent\n"));
 212                 return_VALUE(-ENODEV);
 213         }
 214
 215         /*
 216          * Transition Power
 217          * ----------------
 218          * On transitions to a high-powered state we first apply power (via
 219          * power resources) then evalute _PSx.  Conversly for transitions to
 220          * a lower-powered state.
 221          */
 222         if (state < device->power.state) {
 223                 if (device->power.flags.power_resources) {
 224                         result = acpi_power_transition(device, state);
 225                         if (result)
 226                                 goto end;
 227                 }
 228                 if (device->power.states[state].flags.explicit_set) {
 229                         status = acpi_evaluate_object(device->handle,
 230                                 object_name, NULL, NULL);
 231                         if (ACPI_FAILURE(status)) {
 232                                 result = -ENODEV;
 233                                 goto end;
 234                         }
 235                 }
 236         }
 237         else {
 238                 if (device->power.states[state].flags.explicit_set) {
 239                         status = acpi_evaluate_object(device->handle,
 240                                 object_name, NULL, NULL);
 241                         if (ACPI_FAILURE(status)) {
 242                                 result = -ENODEV;
 243                                 goto end;
 244                         }
 245                 }
 246                 if (device->power.flags.power_resources) {
 247                         result = acpi_power_transition(device, state);
 248                         if (result)
 249                                 goto end;
 250                 }
 251         }
 252
 253 end:
 254         if (result)
 255                 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Error transitioning device [%s] to D%d\n",
 256                         device->pnp.bus_id, state));
 257         else
 258                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] transitioned to D%d\n",
 259                         device->pnp.bus_id, state));
 260
 261         return_VALUE(result);
 262 }
 263
 264
 265
 266 /* --------------------------------------------------------------------------
 267                                 Event Management
 268    -------------------------------------------------------------------------- */
 269
 270 static spinlock_t               acpi_bus_event_lock = SPIN_LOCK_UNLOCKED;
 271
 272 LIST_HEAD(acpi_bus_event_list);
 273 DECLARE_WAIT_QUEUE_HEAD(acpi_bus_event_queue);
 274
 275 extern int                      event_is_open;
 276
 277 int
 278 acpi_bus_generate_event (
 279         struct acpi_device      *device,
 280         u8                      type,
 281         int                     data)
 282 {
 283         struct acpi_bus_event   *event = NULL;
 284         u32                     flags = 0;
 285
 286         ACPI_FUNCTION_TRACE("acpi_bus_generate_event");
 287
 288         if (!device)
 289                 return_VALUE(-EINVAL);
 290
 291         /* drop event on the floor if no one's listening */
 292         if (!event_is_open)
 293                 return_VALUE(0);
 294
 295         event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC);
 296         if (!event)
 297                 return_VALUE(-ENOMEM);
 298
 299         sprintf(event->device_class, "%s", device->pnp.device_class);
 300         sprintf(event->bus_id, "%s", device->pnp.bus_id);
 301         event->type = type;
 302         event->data = data;
 303
 304         spin_lock_irqsave(&acpi_bus_event_lock, flags);
 305         list_add_tail(&event->node, &acpi_bus_event_list);
 306         spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
 307
 308         wake_up_interruptible(&acpi_bus_event_queue);
 309
 310         return_VALUE(0);
 311 }
 312
 313 int
 314 acpi_bus_receive_event (
 315         struct acpi_bus_event   *event)
 316 {
 317         u32                     flags = 0;
 318         struct acpi_bus_event   *entry = NULL;
 319
 320         DECLARE_WAITQUEUE(wait, current);
 321
 322         ACPI_FUNCTION_TRACE("acpi_bus_receive_event");
 323
 324         if (!event)
 325                 return -EINVAL;
 326
 327         if (list_empty(&acpi_bus_event_list)) {
 328
 329                 set_current_state(TASK_INTERRUPTIBLE);
 330                 add_wait_queue(&acpi_bus_event_queue, &wait);
 331
 332                 if (list_empty(&acpi_bus_event_list))
 333                         schedule();
 334
 335                 remove_wait_queue(&acpi_bus_event_queue, &wait);
 336                 set_current_state(TASK_RUNNING);
 337
 338                 if (signal_pending(current))
 339                         return_VALUE(-ERESTARTSYS);
 340         }
 341
 342         spin_lock_irqsave(&acpi_bus_event_lock, flags);
 343         entry = list_entry(acpi_bus_event_list.next, struct acpi_bus_event, node);
 344         if (entry)
 345                 list_del(&entry->node);
 346         spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
 347
 348         if (!entry)
 349                 return_VALUE(-ENODEV);
 350
 351         memcpy(event, entry, sizeof(struct acpi_bus_event));
 352
 353         kfree(entry);
 354
 355         return_VALUE(0);
 356 }
 357
 358
 359 /* --------------------------------------------------------------------------
 360                              Notification Handling
 361    -------------------------------------------------------------------------- */
 362
 363 static int
 364 acpi_bus_check_device (
 365         struct acpi_device      *device,
 366         int                     *status_changed)
 367 {
 368         acpi_status             status = 0;
 369         struct acpi_device_status old_status;
 370
 371         ACPI_FUNCTION_TRACE("acpi_bus_check_device");
 372
 373         if (!device)
 374                 return_VALUE(-EINVAL);
 375
 376         if (status_changed)
 377                 *status_changed = 0;
 378
 379         old_status = device->status;
 380
 381         /*
 382          * Make sure this device's parent is present before we go about
 383          * messing with the device.
 384          */
 385         if (device->parent && !device->parent->status.present) {
 386                 device->status = device->parent->status;
 387                 if (STRUCT_TO_INT(old_status) != STRUCT_TO_INT(device->status)) {
 388                         if (status_changed)
 389                                 *status_changed = 1;
 390                 }
 391                 return_VALUE(0);
 392         }
 393
 394         status = acpi_bus_get_status(device);
 395         if (ACPI_FAILURE(status))
 396                 return_VALUE(-ENODEV);
 397
 398         if (STRUCT_TO_INT(old_status) == STRUCT_TO_INT(device->status))
 399                 return_VALUE(0);
 400
 401         if (status_changed)
 402                 *status_changed = 1;
 403
 404         /*
 405          * Device Insertion/Removal
 406          */
 407         if ((device->status.present) && !(old_status.present)) {
 408                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
 409                 /* TBD: Handle device insertion */
 410         }
 411         else if (!(device->status.present) && (old_status.present)) {
 412                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device removal detected\n"));
 413                 /* TBD: Handle device removal */
 414         }
 415
 416         return_VALUE(0);
 417 }
 418
 419
 420 static int
 421 acpi_bus_check_scope (
 422         struct acpi_device      *device)
 423 {
 424         int                     result = 0;
 425         int                     status_changed = 0;
 426
 427         ACPI_FUNCTION_TRACE("acpi_bus_check_scope");
 428
 429         if (!device)
 430                 return_VALUE(-EINVAL);
 431
 432         /* Status Change? */
 433         result = acpi_bus_check_device(device, &status_changed);
 434         if (result)
 435                 return_VALUE(result);
 436
 437         if (!status_changed)
 438                 return_VALUE(0);
 439
 440         /*
 441          * TBD: Enumerate child devices within this device's scope and
 442          *       run acpi_bus_check_device()'s on them.
 443          */
 444
 445         return_VALUE(0);
 446 }
 447
 448
 449 /**
 450  * acpi_bus_notify
 451  * ---------------
 452  * Callback for all 'system-level' device notifications (values 0x00-0x7F).
 453  */
 454 static void
 455 acpi_bus_notify (
 456         acpi_handle             handle,
 457         u32                     type,
 458         void                    *data)
 459 {
 460         int                     result = 0;
 461         struct acpi_device      *device = NULL;
 462
 463         ACPI_FUNCTION_TRACE("acpi_bus_notify");
 464
 465         if (acpi_bus_get_device(handle, &device))
 466                 return_VOID;
 467
 468         switch (type) {
 469
 470         case ACPI_NOTIFY_BUS_CHECK:
 471                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received BUS CHECK notification for device [%s]\n",
 472                         device->pnp.bus_id));
 473                 result = acpi_bus_check_scope(device);
 474                 /*
 475                  * TBD: We'll need to outsource certain events to non-ACPI
 476                  *      drivers via the device manager (device.c).
 477                  */
 478                 break;
 479
 480         case ACPI_NOTIFY_DEVICE_CHECK:
 481                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received DEVICE CHECK notification for device [%s]\n",
 482                         device->pnp.bus_id));
 483                 result = acpi_bus_check_device(device, NULL);
 484                 /*
 485                  * TBD: We'll need to outsource certain events to non-ACPI
 486                  *      drivers via the device manager (device.c).
 487                  */
 488                 break;
 489
 490         case ACPI_NOTIFY_DEVICE_WAKE:
 491                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received DEVICE WAKE notification for device [%s]\n",
 492                         device->pnp.bus_id));
 493                 /* TBD */
 494                 break;
 495
 496         case ACPI_NOTIFY_EJECT_REQUEST:
 497                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received EJECT REQUEST notification for device [%s]\n",
 498                         device->pnp.bus_id));
 499                 /* TBD */
 500                 break;
 501
 502         case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
 503                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received DEVICE CHECK LIGHT notification for device [%s]\n",
 504                         device->pnp.bus_id));
 505                 /* TBD: Exactly what does 'light' mean? */
 506                 break;
 507
 508         case ACPI_NOTIFY_FREQUENCY_MISMATCH:
 509                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received FREQUENCY MISMATCH notification for device [%s]\n",
 510                         device->pnp.bus_id));
 511                 /* TBD */
 512                 break;
 513
 514         case ACPI_NOTIFY_BUS_MODE_MISMATCH:
 515                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received BUS MODE MISMATCH notification for device [%s]\n",
 516                         device->pnp.bus_id));
 517                 /* TBD */
 518                 break;
 519
 520         case ACPI_NOTIFY_POWER_FAULT:
 521                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received POWER FAULT notification for device [%s]\n",
 522                         device->pnp.bus_id));
 523                 /* TBD */
 524                 break;
 525
 526         default:
 527                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Received unknown/unsupported notification [%08x]\n",
 528                         type));
 529                 break;
 530         }
 531
 532         return_VOID;
 533 }
 534
 535 /* --------------------------------------------------------------------------
 536                              Initialization/Cleanup
 537    -------------------------------------------------------------------------- */
 538
 539 static int __init
 540 acpi_bus_init_irq (void)
 541 {
 542         acpi_status             status = AE_OK;
 543         acpi_object             arg = {ACPI_TYPE_INTEGER};
 544         acpi_object_list        arg_list = {1, &arg};
 545         char                    *message = NULL;
 546
 547         ACPI_FUNCTION_TRACE("acpi_bus_init_irq");
 548
 549         /*
 550          * Let the system know what interrupt model we are using by
 551          * evaluating the \_PIC object, if exists.
 552          */
 553
 554         switch (acpi_irq_model) {
 555         case ACPI_IRQ_MODEL_PIC:
 556                 message = "PIC";
 557                 break;
 558         case ACPI_IRQ_MODEL_IOAPIC:
 559                 message = "IOAPIC";
 560                 break;
 561         case ACPI_IRQ_MODEL_IOSAPIC:
 562                 message = "IOSAPIC";
 563                 break;
 564         default:
 565                 printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
 566                 return_VALUE(-ENODEV);
 567         }
 568
 569         printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);
 570
 571         arg.integer.value = acpi_irq_model;
 572
 573         status = acpi_evaluate_object(NULL, "\\_PIC", &arg_list, NULL);
 574         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 575                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PIC\n"));
 576                 return_VALUE(-ENODEV);
 577         }
 578
 579         return_VALUE(0);
 580 }
 581
 582
 583 static int __init
 584 acpi_bus_init (void)
 585 {
 586         int                     result = 0;
 587         acpi_status             status = AE_OK;
 588         acpi_buffer             buffer = {sizeof(acpi_fadt), &acpi_fadt};
 589
 590         ACPI_FUNCTION_TRACE("acpi_bus_init");
 591
 592         status = acpi_initialize_subsystem();
 593         if (ACPI_FAILURE(status)) {
 594                 printk(KERN_ERR PREFIX "Unable to initialize the ACPI Interpreter\n");
 595                 goto error0;
 596         }
 597
 598         status = acpi_load_tables();
 599         if (ACPI_FAILURE(status)) {
 600                 printk(KERN_ERR PREFIX "Unable to load the System Description Tables\n");
 601                 goto error0;
 602         }
 603
 604         /*
 605          * Get a separate copy of the FADT for use by other drivers.
 606          */
 607         status = acpi_get_table(ACPI_TABLE_FADT, 1, &buffer);
 608         if (ACPI_FAILURE(status)) {
 609                 printk(KERN_ERR PREFIX "Unable to get the FADT\n");
 610                 goto error1;
 611         }
 612
 613 #ifdef CONFIG_X86
 614         /* Ensure the SCI is set to level-triggered, active-low */
 615         if (acpi_ioapic)
 616                 mp_config_ioapic_for_sci(acpi_fadt.sci_int);
 617         else
 618                 eisa_set_level_irq(acpi_fadt.sci_int);
 619 #endif
 620
 621         status = acpi_enable_subsystem(ACPI_FULL_INITIALIZATION);
 622         if (ACPI_FAILURE(status)) {
 623                 printk(KERN_ERR PREFIX "Unable to start the ACPI Interpreter\n");
 624                 goto error1;
 625         }
 626
 627 #ifdef CONFIG_ACPI_EC
 628         /*
 629          * ACPI 2.0 requires the EC driver to be loaded and work before
 630          * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
 631          * is called).
 632          *
 633          * This is accomplished by looking for the ECDT table, and getting
 634          * the EC parameters out of that.
 635          */
 636         status = acpi_ec_ecdt_probe();
 637         if (ACPI_FAILURE(status))
 638                 goto error1;
 639 #endif
 640
 641         status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
 642         if (ACPI_FAILURE(status)) {
 643                 printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
 644                 goto error1;
 645         }
 646
 647         printk(KERN_INFO PREFIX "Interpreter enabled\n");
 648
 649         /*
 650          * Get the system interrupt model and evaluate \_PIC.
 651          */
 652         result = acpi_bus_init_irq();
 653         if (result)
 654                 goto error1;
 655
 656         /*
 657          * Register the for all standard device notifications.
 658          */
 659         status = acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY, &acpi_bus_notify, NULL);
 660         if (ACPI_FAILURE(status)) {
 661                 printk(KERN_ERR PREFIX "Unable to register for device notifications\n");
 662                 goto error1;
 663         }
 664
 665         /*
 666          * Create the top ACPI proc directory
 667          */
 668         acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);
 669
 670         return_VALUE(0);
 671
 672         /* Mimic structured exception handling */
 673 error1:
 674         acpi_terminate();
 675 error0:
 676         return_VALUE(-ENODEV);
 677 }
 678
 679 struct subsystem acpi_subsys = {
 680         .kobj   = { .name = "acpi" },
 681 };
 682
 683 static int __init acpi_init (void)
 684 {
 685         int                     result = 0;
 686
 687         ACPI_FUNCTION_TRACE("acpi_init");
 688
 689         printk(KERN_INFO PREFIX "Subsystem revision %08x\n",
 690                 ACPI_CA_VERSION);
 691
 692         /* Initial core debug level excludes drivers, so include them now */
 693         acpi_set_debug(ACPI_DEBUG_LOW);
 694
 695         if (acpi_disabled) {
 696                 printk(KERN_INFO PREFIX "Disabled via command line (acpi=off)\n");
 697                 return -ENODEV;
 698         }
 699
 700         firmware_register(&acpi_subsys);
 701
 702         result = acpi_bus_init();
 703
 704         if (!result) {
 705 #ifdef CONFIG_PM
 706                 if (!PM_IS_ACTIVE())
 707                         pm_active = 1;
 708                 else {
 709                         printk(KERN_INFO PREFIX "APM is already active, exiting\n");
 710                         acpi_disabled = 1;
 711                         result = -ENODEV;
 712                 }
 713 #endif
 714         } else
 715                 acpi_disabled = 1;
 716
 717         return_VALUE(result);
 718 }
 719
 720
 721 static int __init acpi_setup(char *str)
 722 {
 723         while (str && *str) {
 724                 if (strncmp(str, "off", 3) == 0)
 725                         acpi_disabled = 1;
 726                 str = strchr(str, ',');
 727                 if (str)
 728                         str += strspn(str, ", \t");
 729         }
 730         return 1;
 731 }
 732
 733 subsys_initcall(acpi_init);
 734
 735 __setup("acpi=", acpi_setup);