drivers/acpi/wmi.c

   1 /*
   2  *  ACPI-WMI mapping driver
   3  *
   4  *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
   5  *
   6  *  GUID parsing code from ldm.c is:
   7  *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
   8  *   Copyright (c) 2001-2007 Anton Altaparmakov
   9  *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
  10  *
  11  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; either version 2 of the License, or (at
  16  *  your option) any later version.
  17  *
  18  *  This program is distributed in the hope that it will be useful, but
  19  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21  *  General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License along
  24  *  with this program; if not, write to the Free Software Foundation, Inc.,
  25  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  26  *
  27  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  28  */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/init.h>
  32 #include <linux/types.h>
  33 #include <linux/list.h>
  34 #include <linux/acpi.h>
  35 #include <acpi/acpi_bus.h>
  36 #include <acpi/acpi_drivers.h>
  37
  38 ACPI_MODULE_NAME("wmi");
  39 MODULE_AUTHOR("Carlos Corbacho");
  40 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  41 MODULE_LICENSE("GPL");
  42
  43 #define ACPI_WMI_CLASS "wmi"
  44
  45 #undef PREFIX
  46 #define PREFIX "ACPI: WMI: "
  47
  48 static DEFINE_MUTEX(wmi_data_lock);
  49
  50 struct guid_block {
  51         char guid[16];
  52         union {
  53                 char object_id[2];
  54                 struct {
  55                         unsigned char notify_id;
  56                         unsigned char reserved;
  57                 };
  58         };
  59         u8 instance_count;
  60         u8 flags;
  61 };
  62
  63 struct wmi_block {
  64         struct list_head list;
  65         struct guid_block gblock;
  66         acpi_handle handle;
  67         wmi_notify_handler handler;
  68         void *handler_data;
  69 };
  70
  71 static struct wmi_block wmi_blocks;
  72
  73 /*
  74  * If the GUID data block is marked as expensive, we must enable and
  75  * explicitily disable data collection.
  76  */
  77 #define ACPI_WMI_EXPENSIVE   0x1
  78 #define ACPI_WMI_METHOD      0x2        /* GUID is a method */
  79 #define ACPI_WMI_STRING      0x4        /* GUID takes & returns a string */
  80 #define ACPI_WMI_EVENT       0x8        /* GUID is an event */
  81
  82 static int acpi_wmi_remove(struct acpi_device *device, int type);
  83 static int acpi_wmi_add(struct acpi_device *device);
  84
  85 static const struct acpi_device_id wmi_device_ids[] = {
  86         {"PNP0C14", 0},
  87         {"pnp0c14", 0},
  88         {"", 0},
  89 };
  90 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
  91
  92 static struct acpi_driver acpi_wmi_driver = {
  93         .name = "wmi",
  94         .class = ACPI_WMI_CLASS,
  95         .ids = wmi_device_ids,
  96         .ops = {
  97                 .add = acpi_wmi_add,
  98                 .remove = acpi_wmi_remove,
  99                 },
 100 };
 101
 102 /*
 103  * GUID parsing functions
 104  */
 105
 106 /**
 107  * wmi_parse_hexbyte - Convert a ASCII hex number to a byte
 108  * @src:  Pointer to at least 2 characters to convert.
 109  *
 110  * Convert a two character ASCII hex string to a number.
 111  *
 112  * Return:  0-255  Success, the byte was parsed correctly
 113  *          -1     Error, an invalid character was supplied
 114  */
 115 static int wmi_parse_hexbyte(const u8 *src)
 116 {
 117         unsigned int x; /* For correct wrapping */
 118         int h;
 119
 120         /* high part */
 121         x = src[0];
 122         if (x - '0' <= '9' - '0') {
 123                 h = x - '0';
 124         } else if (x - 'a' <= 'f' - 'a') {
 125                 h = x - 'a' + 10;
 126         } else if (x - 'A' <= 'F' - 'A') {
 127                 h = x - 'A' + 10;
 128         } else {
 129                 return -1;
 130         }
 131         h <<= 4;
 132
 133         /* low part */
 134         x = src[1];
 135         if (x - '0' <= '9' - '0')
 136                 return h | (x - '0');
 137         if (x - 'a' <= 'f' - 'a')
 138                 return h | (x - 'a' + 10);
 139         if (x - 'A' <= 'F' - 'A')
 140                 return h | (x - 'A' + 10);
 141         return -1;
 142 }
 143
 144 /**
 145  * wmi_swap_bytes - Rearrange GUID bytes to match GUID binary
 146  * @src:   Memory block holding binary GUID (16 bytes)
 147  * @dest:  Memory block to hold byte swapped binary GUID (16 bytes)
 148  *
 149  * Byte swap a binary GUID to match it's real GUID value
 150  */
 151 static void wmi_swap_bytes(u8 *src, u8 *dest)
 152 {
 153         int i;
 154
 155         for (i = 0; i <= 3; i++)
 156                 memcpy(dest + i, src + (3 - i), 1);
 157
 158         for (i = 0; i <= 1; i++)
 159                 memcpy(dest + 4 + i, src + (5 - i), 1);
 160
 161         for (i = 0; i <= 1; i++)
 162                 memcpy(dest + 6 + i, src + (7 - i), 1);
 163
 164         memcpy(dest + 8, src + 8, 8);
 165 }
 166
 167 /**
 168  * wmi_parse_guid - Convert GUID from ASCII to binary
 169  * @src:   36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 170  * @dest:  Memory block to hold binary GUID (16 bytes)
 171  *
 172  * N.B. The GUID need not be NULL terminated.
 173  *
 174  * Return:  'true'   @dest contains binary GUID
 175  *          'false'  @dest contents are undefined
 176  */
 177 static bool wmi_parse_guid(const u8 *src, u8 *dest)
 178 {
 179         static const int size[] = { 4, 2, 2, 2, 6 };
 180         int i, j, v;
 181
 182         if (src[8]  != '-' || src[13] != '-' ||
 183                 src[18] != '-' || src[23] != '-')
 184                 return false;
 185
 186         for (j = 0; j < 5; j++, src++) {
 187                 for (i = 0; i < size[j]; i++, src += 2, *dest++ = v) {
 188                         v = wmi_parse_hexbyte(src);
 189                         if (v < 0)
 190                                 return false;
 191                 }
 192         }
 193
 194         return true;
 195 }
 196
 197 static bool find_guid(const char *guid_string, struct wmi_block **out)
 198 {
 199         char tmp[16], guid_input[16];
 200         struct wmi_block *wblock;
 201         struct guid_block *block;
 202         struct list_head *p;
 203
 204         wmi_parse_guid(guid_string, tmp);
 205         wmi_swap_bytes(tmp, guid_input);
 206
 207         list_for_each(p, &wmi_blocks.list) {
 208                 wblock = list_entry(p, struct wmi_block, list);
 209                 block = &wblock->gblock;
 210
 211                 if (memcmp(block->guid, guid_input, 16) == 0) {
 212                         if (out)
 213                                 *out = wblock;
 214                         return 1;
 215                 }
 216         }
 217         return 0;
 218 }
 219
 220 /*
 221  * Exported WMI functions
 222  */
 223 /**
 224  * wmi_evaluate_method - Evaluate a WMI method
 225  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 226  * @instance: Instance index
 227  * @method_id: Method ID to call
 228  * &in: Buffer containing input for the method call
 229  * &out: Empty buffer to return the method results
 230  *
 231  * Call an ACPI-WMI method
 232  */
 233 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
 234 u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
 235 {
 236         struct guid_block *block = NULL;
 237         struct wmi_block *wblock = NULL;
 238         acpi_handle handle;
 239         acpi_status status;
 240         struct acpi_object_list input;
 241         union acpi_object params[3];
 242         char method[4] = "WM";
 243
 244         if (!find_guid(guid_string, &wblock))
 245                 return AE_BAD_ADDRESS;
 246
 247         block = &wblock->gblock;
 248         handle = wblock->handle;
 249
 250         if (!(block->flags & ACPI_WMI_METHOD))
 251                 return AE_BAD_DATA;
 252
 253         if (block->instance_count < instance)
 254                 return AE_BAD_PARAMETER;
 255
 256         input.count = 2;
 257         input.pointer = params;
 258         params[0].type = ACPI_TYPE_INTEGER;
 259         params[0].integer.value = instance;
 260         params[1].type = ACPI_TYPE_INTEGER;
 261         params[1].integer.value = method_id;
 262
 263         if (in) {
 264                 input.count = 3;
 265
 266                 if (block->flags & ACPI_WMI_STRING) {
 267                         params[2].type = ACPI_TYPE_STRING;
 268                 } else {
 269                         params[2].type = ACPI_TYPE_BUFFER;
 270                 }
 271                 params[2].buffer.length = in->length;
 272                 params[2].buffer.pointer = in->pointer;
 273         }
 274
 275         strncat(method, block->object_id, 2);
 276
 277         status = acpi_evaluate_object(handle, method, &input, out);
 278
 279         return status;
 280 }
 281 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
 282
 283 /**
 284  * wmi_query_block - Return contents of a WMI block
 285  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 286  * @instance: Instance index
 287  * &out: Empty buffer to return the contents of the data block to
 288  *
 289  * Return the contents of an ACPI-WMI data block to a buffer
 290  */
 291 acpi_status wmi_query_block(const char *guid_string, u8 instance,
 292 struct acpi_buffer *out)
 293 {
 294         struct guid_block *block = NULL;
 295         struct wmi_block *wblock = NULL;
 296         acpi_handle handle, wc_handle;
 297         acpi_status status, wc_status = AE_ERROR;
 298         struct acpi_object_list input, wc_input;
 299         union acpi_object wc_params[1], wq_params[1];
 300         char method[4];
 301         char wc_method[4] = "WC";
 302
 303         if (!guid_string || !out)
 304                 return AE_BAD_PARAMETER;
 305
 306         if (!find_guid(guid_string, &wblock))
 307                 return AE_BAD_ADDRESS;
 308
 309         block = &wblock->gblock;
 310         handle = wblock->handle;
 311
 312         if (block->instance_count < instance)
 313                 return AE_BAD_PARAMETER;
 314
 315         /* Check GUID is a data block */
 316         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 317                 return AE_BAD_ADDRESS;
 318
 319         input.count = 1;
 320         input.pointer = wq_params;
 321         wq_params[0].type = ACPI_TYPE_INTEGER;
 322         wq_params[0].integer.value = instance;
 323
 324         /*
 325          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
 326          * enable collection.
 327          */
 328         if (block->flags & ACPI_WMI_EXPENSIVE) {
 329                 wc_input.count = 1;
 330                 wc_input.pointer = wc_params;
 331                 wc_params[0].type = ACPI_TYPE_INTEGER;
 332                 wc_params[0].integer.value = 1;
 333
 334                 strncat(wc_method, block->object_id, 2);
 335
 336                 /*
 337                  * Some GUIDs break the specification by declaring themselves
 338                  * expensive, but have no corresponding WCxx method. So we
 339                  * should not fail if this happens.
 340                  */
 341                 wc_status = acpi_get_handle(handle, wc_method, &wc_handle);
 342                 if (ACPI_SUCCESS(wc_status))
 343                         wc_status = acpi_evaluate_object(handle, wc_method,
 344                                 &wc_input, NULL);
 345         }
 346
 347         strcpy(method, "WQ");
 348         strncat(method, block->object_id, 2);
 349
 350         status = acpi_evaluate_object(handle, method, &input, out);
 351
 352         /*
 353          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
 354          * the WQxx method failed - we should disable collection anyway.
 355          */
 356         if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
 357                 wc_params[0].integer.value = 0;
 358                 status = acpi_evaluate_object(handle,
 359                 wc_method, &wc_input, NULL);
 360         }
 361
 362         return status;
 363 }
 364 EXPORT_SYMBOL_GPL(wmi_query_block);
 365
 366 /**
 367  * wmi_set_block - Write to a WMI block
 368  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 369  * @instance: Instance index
 370  * &in: Buffer containing new values for the data block
 371  *
 372  * Write the contents of the input buffer to an ACPI-WMI data block
 373  */
 374 acpi_status wmi_set_block(const char *guid_string, u8 instance,
 375 const struct acpi_buffer *in)
 376 {
 377         struct guid_block *block = NULL;
 378         struct wmi_block *wblock = NULL;
 379         acpi_handle handle;
 380         struct acpi_object_list input;
 381         union acpi_object params[2];
 382         char method[4] = "WS";
 383
 384         if (!guid_string || !in)
 385                 return AE_BAD_DATA;
 386
 387         if (!find_guid(guid_string, &wblock))
 388                 return AE_BAD_ADDRESS;
 389
 390         block = &wblock->gblock;
 391         handle = wblock->handle;
 392
 393         if (block->instance_count < instance)
 394                 return AE_BAD_PARAMETER;
 395
 396         /* Check GUID is a data block */
 397         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 398                 return AE_BAD_ADDRESS;
 399
 400         input.count = 2;
 401         input.pointer = params;
 402         params[0].type = ACPI_TYPE_INTEGER;
 403         params[0].integer.value = instance;
 404
 405         if (block->flags & ACPI_WMI_STRING) {
 406                 params[1].type = ACPI_TYPE_STRING;
 407         } else {
 408                 params[1].type = ACPI_TYPE_BUFFER;
 409         }
 410         params[1].buffer.length = in->length;
 411         params[1].buffer.pointer = in->pointer;
 412
 413         strncat(method, block->object_id, 2);
 414
 415         return acpi_evaluate_object(handle, method, &input, NULL);
 416 }
 417 EXPORT_SYMBOL_GPL(wmi_set_block);
 418
 419 /**
 420  * wmi_install_notify_handler - Register handler for WMI events
 421  * @handler: Function to handle notifications
 422  * @data: Data to be returned to handler when event is fired
 423  *
 424  * Register a handler for events sent to the ACPI-WMI mapper device.
 425  */
 426 acpi_status wmi_install_notify_handler(const char *guid,
 427 wmi_notify_handler handler, void *data)
 428 {
 429         struct wmi_block *block;
 430
 431         if (!guid || !handler)
 432                 return AE_BAD_PARAMETER;
 433
 434         find_guid(guid, &block);
 435         if (!block)
 436                 return AE_NOT_EXIST;
 437
 438         if (block->handler)
 439                 return AE_ALREADY_ACQUIRED;
 440
 441         block->handler = handler;
 442         block->handler_data = data;
 443
 444         return AE_OK;
 445 }
 446 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 447
 448 /**
 449  * wmi_uninstall_notify_handler - Unregister handler for WMI events
 450  *
 451  * Unregister handler for events sent to the ACPI-WMI mapper device.
 452  */
 453 acpi_status wmi_remove_notify_handler(const char *guid)
 454 {
 455         struct wmi_block *block;
 456
 457         if (!guid)
 458                 return AE_BAD_PARAMETER;
 459
 460         find_guid(guid, &block);
 461         if (!block)
 462                 return AE_NOT_EXIST;
 463
 464         if (!block->handler)
 465                 return AE_NULL_ENTRY;
 466
 467         block->handler = NULL;
 468         block->handler_data = NULL;
 469
 470         return AE_OK;
 471 }
 472 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 473
 474 /**
 475  * wmi_get_event_data - Get WMI data associated with an event
 476  *
 477  * @event - Event to find
 478  * &out - Buffer to hold event data
 479  *
 480  * Returns extra data associated with an event in WMI.
 481  */
 482 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
 483 {
 484         struct acpi_object_list input;
 485         union acpi_object params[1];
 486         struct guid_block *gblock;
 487         struct wmi_block *wblock;
 488         struct list_head *p;
 489
 490         input.count = 1;
 491         input.pointer = params;
 492         params[0].type = ACPI_TYPE_INTEGER;
 493         params[0].integer.value = event;
 494
 495         list_for_each(p, &wmi_blocks.list) {
 496                 wblock = list_entry(p, struct wmi_block, list);
 497                 gblock = &wblock->gblock;
 498
 499                 if ((gblock->flags & ACPI_WMI_EVENT) &&
 500                         (gblock->notify_id == event))
 501                         return acpi_evaluate_object(wblock->handle, "_WED",
 502                                 &input, out);
 503         }
 504
 505         return AE_NOT_FOUND;
 506 }
 507 EXPORT_SYMBOL_GPL(wmi_get_event_data);
 508
 509 /**
 510  * wmi_has_guid - Check if a GUID is available
 511  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 512  *
 513  * Check if a given GUID is defined by _WDG
 514  */
 515 bool wmi_has_guid(const char *guid_string)
 516 {
 517         return find_guid(guid_string, NULL);
 518 }
 519 EXPORT_SYMBOL_GPL(wmi_has_guid);
 520
 521 /*
 522  * Parse the _WDG method for the GUID data blocks
 523  */
 524 static __init acpi_status parse_wdg(acpi_handle handle)
 525 {
 526         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
 527         union acpi_object *obj;
 528         struct guid_block *gblock;
 529         struct wmi_block *wblock;
 530         acpi_status status;
 531         u32 i, total;
 532
 533         status = acpi_evaluate_object(handle, "_WDG", NULL, &out);
 534
 535         if (ACPI_FAILURE(status))
 536                 return status;
 537
 538         obj = (union acpi_object *) out.pointer;
 539
 540         if (obj->type != ACPI_TYPE_BUFFER)
 541                 return AE_ERROR;
 542
 543         total = obj->buffer.length / sizeof(struct guid_block);
 544
 545         gblock = kzalloc(obj->buffer.length, GFP_KERNEL);
 546         if (!gblock)
 547                 return AE_NO_MEMORY;
 548
 549         memcpy(gblock, obj->buffer.pointer, obj->buffer.length);
 550
 551         for (i = 0; i < total; i++) {
 552                 wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
 553                 if (!wblock)
 554                         return AE_NO_MEMORY;
 555
 556                 wblock->gblock = gblock[i];
 557                 wblock->handle = handle;
 558                 list_add_tail(&wblock->list, &wmi_blocks.list);
 559         }
 560
 561         kfree(out.pointer);
 562         kfree(gblock);
 563
 564         return status;
 565 }
 566
 567 /*
 568  * WMI can have EmbeddedControl access regions. In which case, we just want to
 569  * hand these off to the EC driver.
 570  */
 571 static acpi_status
 572 acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
 573                       u32 bits, acpi_integer * value,
 574                       void *handler_context, void *region_context)
 575 {
 576         int result = 0, i = 0;
 577         u8 temp = 0;
 578
 579         if ((address > 0xFF) || !value)
 580                 return AE_BAD_PARAMETER;
 581
 582         if (function != ACPI_READ && function != ACPI_WRITE)
 583                 return AE_BAD_PARAMETER;
 584
 585         if (bits != 8)
 586                 return AE_BAD_PARAMETER;
 587
 588         if (function == ACPI_READ) {
 589                 result = ec_read(address, &temp);
 590                 (*value) |= ((acpi_integer)temp) << i;
 591         } else {
 592                 temp = 0xff & ((*value) >> i);
 593                 result = ec_write(address, temp);
 594         }
 595
 596         switch (result) {
 597         case -EINVAL:
 598                 return AE_BAD_PARAMETER;
 599                 break;
 600         case -ENODEV:
 601                 return AE_NOT_FOUND;
 602                 break;
 603         case -ETIME:
 604                 return AE_TIME;
 605                 break;
 606         default:
 607                 return AE_OK;
 608         }
 609 }
 610
 611 static void acpi_wmi_notify(acpi_handle handle, u32 event, void *data)
 612 {
 613         struct guid_block *block;
 614         struct wmi_block *wblock;
 615         struct list_head *p;
 616         struct acpi_device *device = data;
 617
 618         list_for_each(p, &wmi_blocks.list) {
 619                 wblock = list_entry(p, struct wmi_block, list);
 620                 block = &wblock->gblock;
 621
 622                 if ((block->flags & ACPI_WMI_EVENT) &&
 623                         (block->notify_id == event)) {
 624                         if (wblock->handler)
 625                                 wblock->handler(event, wblock->handler_data);
 626
 627                         acpi_bus_generate_netlink_event(
 628                                 device->pnp.device_class, device->dev.bus_id,
 629                                 event, 0);
 630                         break;
 631                 }
 632         }
 633 }
 634
 635 static int acpi_wmi_remove(struct acpi_device *device, int type)
 636 {
 637         acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
 638                 acpi_wmi_notify);
 639
 640         acpi_remove_address_space_handler(device->handle,
 641                                 ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
 642
 643         return 0;
 644 }
 645
 646 static int __init acpi_wmi_add(struct acpi_device *device)
 647 {
 648         acpi_status status;
 649         int result = 0;
 650
 651         status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
 652                 acpi_wmi_notify, device);
 653         if (ACPI_FAILURE(status)) {
 654                 printk(KERN_ERR PREFIX "Error installing notify handler\n");
 655                 return -ENODEV;
 656         }
 657
 658         status = acpi_install_address_space_handler(device->handle,
 659                                                     ACPI_ADR_SPACE_EC,
 660                                                     &acpi_wmi_ec_space_handler,
 661                                                     NULL, NULL);
 662         if (ACPI_FAILURE(status))
 663                 return -ENODEV;
 664
 665         status = parse_wdg(device->handle);
 666         if (ACPI_FAILURE(status)) {
 667                 printk(KERN_ERR PREFIX "Error installing EC region handler\n");
 668                 return -ENODEV;
 669         }
 670
 671         return result;
 672 }
 673
 674 static int __init acpi_wmi_init(void)
 675 {
 676         acpi_status result;
 677
 678         INIT_LIST_HEAD(&wmi_blocks.list);
 679
 680         if (acpi_disabled)
 681                 return -ENODEV;
 682
 683         result = acpi_bus_register_driver(&acpi_wmi_driver);
 684
 685         if (result < 0) {
 686                 printk(KERN_INFO PREFIX "Error loading mapper\n");
 687         } else {
 688                 printk(KERN_INFO PREFIX "Mapper loaded\n");
 689         }
 690
 691         return result;
 692 }
 693
 694 static void __exit acpi_wmi_exit(void)
 695 {
 696         struct list_head *p, *tmp;
 697         struct wmi_block *wblock;
 698
 699         acpi_bus_unregister_driver(&acpi_wmi_driver);
 700
 701         list_for_each_safe(p, tmp, &wmi_blocks.list) {
 702                 wblock = list_entry(p, struct wmi_block, list);
 703
 704                 list_del(p);
 705                 kfree(wblock);
 706         }
 707
 708         printk(KERN_INFO PREFIX "Mapper unloaded\n");
 709 }
 710
 711 subsys_initcall(acpi_wmi_init);
 712 module_exit(acpi_wmi_exit);