drivers/platform/x86/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 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  31
  32 #include <linux/kernel.h>
  33 #include <linux/init.h>
  34 #include <linux/types.h>
  35 #include <linux/device.h>
  36 #include <linux/list.h>
  37 #include <linux/acpi.h>
  38 #include <linux/slab.h>
  39 #include <linux/module.h>
  40 #include <acpi/acpi_bus.h>
  41 #include <acpi/acpi_drivers.h>
  42
  43 ACPI_MODULE_NAME("wmi");
  44 MODULE_AUTHOR("Carlos Corbacho");
  45 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  46 MODULE_LICENSE("GPL");
  47
  48 #define ACPI_WMI_CLASS "wmi"
  49
  50 static DEFINE_MUTEX(wmi_data_lock);
  51 static LIST_HEAD(wmi_block_list);
  52
  53 struct guid_block {
  54         char guid[16];
  55         union {
  56                 char object_id[2];
  57                 struct {
  58                         unsigned char notify_id;
  59                         unsigned char reserved;
  60                 };
  61         };
  62         u8 instance_count;
  63         u8 flags;
  64 };
  65
  66 struct wmi_block {
  67         struct list_head list;
  68         struct guid_block gblock;
  69         acpi_handle handle;
  70         wmi_notify_handler handler;
  71         void *handler_data;
  72         struct device dev;
  73 };
  74
  75
  76 /*
  77  * If the GUID data block is marked as expensive, we must enable and
  78  * explicitily disable data collection.
  79  */
  80 #define ACPI_WMI_EXPENSIVE   0x1
  81 #define ACPI_WMI_METHOD      0x2        /* GUID is a method */
  82 #define ACPI_WMI_STRING      0x4        /* GUID takes & returns a string */
  83 #define ACPI_WMI_EVENT       0x8        /* GUID is an event */
  84
  85 static bool debug_event;
  86 module_param(debug_event, bool, 0444);
  87 MODULE_PARM_DESC(debug_event,
  88                  "Log WMI Events [0/1]");
  89
  90 static bool debug_dump_wdg;
  91 module_param(debug_dump_wdg, bool, 0444);
  92 MODULE_PARM_DESC(debug_dump_wdg,
  93                  "Dump available WMI interfaces [0/1]");
  94
  95 static int acpi_wmi_remove(struct acpi_device *device);
  96 static int acpi_wmi_add(struct acpi_device *device);
  97 static void acpi_wmi_notify(struct acpi_device *device, u32 event);
  98
  99 static const struct acpi_device_id wmi_device_ids[] = {
 100         {"PNP0C14", 0},
 101         {"pnp0c14", 0},
 102         {"", 0},
 103 };
 104 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
 105
 106 static struct acpi_driver acpi_wmi_driver = {
 107         .name = "wmi",
 108         .class = ACPI_WMI_CLASS,
 109         .ids = wmi_device_ids,
 110         .ops = {
 111                 .add = acpi_wmi_add,
 112                 .remove = acpi_wmi_remove,
 113                 .notify = acpi_wmi_notify,
 114         },
 115 };
 116
 117 /*
 118  * GUID parsing functions
 119  */
 120
 121 /**
 122  * wmi_parse_hexbyte - Convert a ASCII hex number to a byte
 123  * @src:  Pointer to at least 2 characters to convert.
 124  *
 125  * Convert a two character ASCII hex string to a number.
 126  *
 127  * Return:  0-255  Success, the byte was parsed correctly
 128  *          -1     Error, an invalid character was supplied
 129  */
 130 static int wmi_parse_hexbyte(const u8 *src)
 131 {
 132         int h;
 133         int value;
 134
 135         /* high part */
 136         h = value = hex_to_bin(src[0]);
 137         if (value < 0)
 138                 return -1;
 139
 140         /* low part */
 141         value = hex_to_bin(src[1]);
 142         if (value >= 0)
 143                 return (h << 4) | value;
 144         return -1;
 145 }
 146
 147 /**
 148  * wmi_swap_bytes - Rearrange GUID bytes to match GUID binary
 149  * @src:   Memory block holding binary GUID (16 bytes)
 150  * @dest:  Memory block to hold byte swapped binary GUID (16 bytes)
 151  *
 152  * Byte swap a binary GUID to match it's real GUID value
 153  */
 154 static void wmi_swap_bytes(u8 *src, u8 *dest)
 155 {
 156         int i;
 157
 158         for (i = 0; i <= 3; i++)
 159                 memcpy(dest + i, src + (3 - i), 1);
 160
 161         for (i = 0; i <= 1; i++)
 162                 memcpy(dest + 4 + i, src + (5 - i), 1);
 163
 164         for (i = 0; i <= 1; i++)
 165                 memcpy(dest + 6 + i, src + (7 - i), 1);
 166
 167         memcpy(dest + 8, src + 8, 8);
 168 }
 169
 170 /**
 171  * wmi_parse_guid - Convert GUID from ASCII to binary
 172  * @src:   36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 173  * @dest:  Memory block to hold binary GUID (16 bytes)
 174  *
 175  * N.B. The GUID need not be NULL terminated.
 176  *
 177  * Return:  'true'   @dest contains binary GUID
 178  *          'false'  @dest contents are undefined
 179  */
 180 static bool wmi_parse_guid(const u8 *src, u8 *dest)
 181 {
 182         static const int size[] = { 4, 2, 2, 2, 6 };
 183         int i, j, v;
 184
 185         if (src[8]  != '-' || src[13] != '-' ||
 186                 src[18] != '-' || src[23] != '-')
 187                 return false;
 188
 189         for (j = 0; j < 5; j++, src++) {
 190                 for (i = 0; i < size[j]; i++, src += 2, *dest++ = v) {
 191                         v = wmi_parse_hexbyte(src);
 192                         if (v < 0)
 193                                 return false;
 194                 }
 195         }
 196
 197         return true;
 198 }
 199
 200 /*
 201  * Convert a raw GUID to the ACII string representation
 202  */
 203 static int wmi_gtoa(const char *in, char *out)
 204 {
 205         int i;
 206
 207         for (i = 3; i >= 0; i--)
 208                 out += sprintf(out, "%02X", in[i] & 0xFF);
 209
 210         out += sprintf(out, "-");
 211         out += sprintf(out, "%02X", in[5] & 0xFF);
 212         out += sprintf(out, "%02X", in[4] & 0xFF);
 213         out += sprintf(out, "-");
 214         out += sprintf(out, "%02X", in[7] & 0xFF);
 215         out += sprintf(out, "%02X", in[6] & 0xFF);
 216         out += sprintf(out, "-");
 217         out += sprintf(out, "%02X", in[8] & 0xFF);
 218         out += sprintf(out, "%02X", in[9] & 0xFF);
 219         out += sprintf(out, "-");
 220
 221         for (i = 10; i <= 15; i++)
 222                 out += sprintf(out, "%02X", in[i] & 0xFF);
 223
 224         *out = '\0';
 225         return 0;
 226 }
 227
 228 static bool find_guid(const char *guid_string, struct wmi_block **out)
 229 {
 230         char tmp[16], guid_input[16];
 231         struct wmi_block *wblock;
 232         struct guid_block *block;
 233         struct list_head *p;
 234
 235         wmi_parse_guid(guid_string, tmp);
 236         wmi_swap_bytes(tmp, guid_input);
 237
 238         list_for_each(p, &wmi_block_list) {
 239                 wblock = list_entry(p, struct wmi_block, list);
 240                 block = &wblock->gblock;
 241
 242                 if (memcmp(block->guid, guid_input, 16) == 0) {
 243                         if (out)
 244                                 *out = wblock;
 245                         return 1;
 246                 }
 247         }
 248         return 0;
 249 }
 250
 251 static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
 252 {
 253         struct guid_block *block = NULL;
 254         char method[5];
 255         acpi_status status;
 256         acpi_handle handle;
 257
 258         block = &wblock->gblock;
 259         handle = wblock->handle;
 260
 261         if (!block)
 262                 return AE_NOT_EXIST;
 263
 264
 265         snprintf(method, 5, "WE%02X", block->notify_id);
 266         status = acpi_execute_simple_method(handle, method, enable);
 267
 268         if (status != AE_OK && status != AE_NOT_FOUND)
 269                 return status;
 270         else
 271                 return AE_OK;
 272 }
 273
 274 /*
 275  * Exported WMI functions
 276  */
 277 /**
 278  * wmi_evaluate_method - Evaluate a WMI method
 279  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 280  * @instance: Instance index
 281  * @method_id: Method ID to call
 282  * &in: Buffer containing input for the method call
 283  * &out: Empty buffer to return the method results
 284  *
 285  * Call an ACPI-WMI method
 286  */
 287 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
 288 u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
 289 {
 290         struct guid_block *block = NULL;
 291         struct wmi_block *wblock = NULL;
 292         acpi_handle handle;
 293         acpi_status status;
 294         struct acpi_object_list input;
 295         union acpi_object params[3];
 296         char method[5] = "WM";
 297
 298         if (!find_guid(guid_string, &wblock))
 299                 return AE_ERROR;
 300
 301         block = &wblock->gblock;
 302         handle = wblock->handle;
 303
 304         if (!(block->flags & ACPI_WMI_METHOD))
 305                 return AE_BAD_DATA;
 306
 307         if (block->instance_count < instance)
 308                 return AE_BAD_PARAMETER;
 309
 310         input.count = 2;
 311         input.pointer = params;
 312         params[0].type = ACPI_TYPE_INTEGER;
 313         params[0].integer.value = instance;
 314         params[1].type = ACPI_TYPE_INTEGER;
 315         params[1].integer.value = method_id;
 316
 317         if (in) {
 318                 input.count = 3;
 319
 320                 if (block->flags & ACPI_WMI_STRING) {
 321                         params[2].type = ACPI_TYPE_STRING;
 322                 } else {
 323                         params[2].type = ACPI_TYPE_BUFFER;
 324                 }
 325                 params[2].buffer.length = in->length;
 326                 params[2].buffer.pointer = in->pointer;
 327         }
 328
 329         strncat(method, block->object_id, 2);
 330
 331         status = acpi_evaluate_object(handle, method, &input, out);
 332
 333         return status;
 334 }
 335 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
 336
 337 /**
 338  * wmi_query_block - Return contents of a WMI block
 339  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 340  * @instance: Instance index
 341  * &out: Empty buffer to return the contents of the data block to
 342  *
 343  * Return the contents of an ACPI-WMI data block to a buffer
 344  */
 345 acpi_status wmi_query_block(const char *guid_string, u8 instance,
 346 struct acpi_buffer *out)
 347 {
 348         struct guid_block *block = NULL;
 349         struct wmi_block *wblock = NULL;
 350         acpi_handle handle;
 351         acpi_status status, wc_status = AE_ERROR;
 352         struct acpi_object_list input;
 353         union acpi_object wq_params[1];
 354         char method[5];
 355         char wc_method[5] = "WC";
 356
 357         if (!guid_string || !out)
 358                 return AE_BAD_PARAMETER;
 359
 360         if (!find_guid(guid_string, &wblock))
 361                 return AE_ERROR;
 362
 363         block = &wblock->gblock;
 364         handle = wblock->handle;
 365
 366         if (block->instance_count < instance)
 367                 return AE_BAD_PARAMETER;
 368
 369         /* Check GUID is a data block */
 370         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 371                 return AE_ERROR;
 372
 373         input.count = 1;
 374         input.pointer = wq_params;
 375         wq_params[0].type = ACPI_TYPE_INTEGER;
 376         wq_params[0].integer.value = instance;
 377
 378         /*
 379          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
 380          * enable collection.
 381          */
 382         if (block->flags & ACPI_WMI_EXPENSIVE) {
 383                 strncat(wc_method, block->object_id, 2);
 384
 385                 /*
 386                  * Some GUIDs break the specification by declaring themselves
 387                  * expensive, but have no corresponding WCxx method. So we
 388                  * should not fail if this happens.
 389                  */
 390                 if (acpi_has_method(handle, wc_method))
 391                         wc_status = acpi_execute_simple_method(handle,
 392                                                                 wc_method, 1);
 393         }
 394
 395         strcpy(method, "WQ");
 396         strncat(method, block->object_id, 2);
 397
 398         status = acpi_evaluate_object(handle, method, &input, out);
 399
 400         /*
 401          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
 402          * the WQxx method failed - we should disable collection anyway.
 403          */
 404         if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
 405                 status = acpi_execute_simple_method(handle, wc_method, 0);
 406         }
 407
 408         return status;
 409 }
 410 EXPORT_SYMBOL_GPL(wmi_query_block);
 411
 412 /**
 413  * wmi_set_block - Write to a WMI block
 414  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 415  * @instance: Instance index
 416  * &in: Buffer containing new values for the data block
 417  *
 418  * Write the contents of the input buffer to an ACPI-WMI data block
 419  */
 420 acpi_status wmi_set_block(const char *guid_string, u8 instance,
 421 const struct acpi_buffer *in)
 422 {
 423         struct guid_block *block = NULL;
 424         struct wmi_block *wblock = NULL;
 425         acpi_handle handle;
 426         struct acpi_object_list input;
 427         union acpi_object params[2];
 428         char method[5] = "WS";
 429
 430         if (!guid_string || !in)
 431                 return AE_BAD_DATA;
 432
 433         if (!find_guid(guid_string, &wblock))
 434                 return AE_ERROR;
 435
 436         block = &wblock->gblock;
 437         handle = wblock->handle;
 438
 439         if (block->instance_count < instance)
 440                 return AE_BAD_PARAMETER;
 441
 442         /* Check GUID is a data block */
 443         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 444                 return AE_ERROR;
 445
 446         input.count = 2;
 447         input.pointer = params;
 448         params[0].type = ACPI_TYPE_INTEGER;
 449         params[0].integer.value = instance;
 450
 451         if (block->flags & ACPI_WMI_STRING) {
 452                 params[1].type = ACPI_TYPE_STRING;
 453         } else {
 454                 params[1].type = ACPI_TYPE_BUFFER;
 455         }
 456         params[1].buffer.length = in->length;
 457         params[1].buffer.pointer = in->pointer;
 458
 459         strncat(method, block->object_id, 2);
 460
 461         return acpi_evaluate_object(handle, method, &input, NULL);
 462 }
 463 EXPORT_SYMBOL_GPL(wmi_set_block);
 464
 465 static void wmi_dump_wdg(const struct guid_block *g)
 466 {
 467         char guid_string[37];
 468
 469         wmi_gtoa(g->guid, guid_string);
 470
 471         pr_info("%s:\n", guid_string);
 472         pr_info("\tobject_id: %c%c\n", g->object_id[0], g->object_id[1]);
 473         pr_info("\tnotify_id: %02X\n", g->notify_id);
 474         pr_info("\treserved: %02X\n", g->reserved);
 475         pr_info("\tinstance_count: %d\n", g->instance_count);
 476         pr_info("\tflags: %#x", g->flags);
 477         if (g->flags) {
 478                 if (g->flags & ACPI_WMI_EXPENSIVE)
 479                         pr_cont(" ACPI_WMI_EXPENSIVE");
 480                 if (g->flags & ACPI_WMI_METHOD)
 481                         pr_cont(" ACPI_WMI_METHOD");
 482                 if (g->flags & ACPI_WMI_STRING)
 483                         pr_cont(" ACPI_WMI_STRING");
 484                 if (g->flags & ACPI_WMI_EVENT)
 485                         pr_cont(" ACPI_WMI_EVENT");
 486         }
 487         pr_cont("\n");
 488
 489 }
 490
 491 static void wmi_notify_debug(u32 value, void *context)
 492 {
 493         struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
 494         union acpi_object *obj;
 495         acpi_status status;
 496
 497         status = wmi_get_event_data(value, &response);
 498         if (status != AE_OK) {
 499                 pr_info("bad event status 0x%x\n", status);
 500                 return;
 501         }
 502
 503         obj = (union acpi_object *)response.pointer;
 504
 505         if (!obj)
 506                 return;
 507
 508         pr_info("DEBUG Event ");
 509         switch(obj->type) {
 510         case ACPI_TYPE_BUFFER:
 511                 pr_cont("BUFFER_TYPE - length %d\n", obj->buffer.length);
 512                 break;
 513         case ACPI_TYPE_STRING:
 514                 pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
 515                 break;
 516         case ACPI_TYPE_INTEGER:
 517                 pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
 518                 break;
 519         case ACPI_TYPE_PACKAGE:
 520                 pr_cont("PACKAGE_TYPE - %d elements\n", obj->package.count);
 521                 break;
 522         default:
 523                 pr_cont("object type 0x%X\n", obj->type);
 524         }
 525         kfree(obj);
 526 }
 527
 528 /**
 529  * wmi_install_notify_handler - Register handler for WMI events
 530  * @handler: Function to handle notifications
 531  * @data: Data to be returned to handler when event is fired
 532  *
 533  * Register a handler for events sent to the ACPI-WMI mapper device.
 534  */
 535 acpi_status wmi_install_notify_handler(const char *guid,
 536 wmi_notify_handler handler, void *data)
 537 {
 538         struct wmi_block *block;
 539         acpi_status status = AE_NOT_EXIST;
 540         char tmp[16], guid_input[16];
 541         struct list_head *p;
 542
 543         if (!guid || !handler)
 544                 return AE_BAD_PARAMETER;
 545
 546         wmi_parse_guid(guid, tmp);
 547         wmi_swap_bytes(tmp, guid_input);
 548
 549         list_for_each(p, &wmi_block_list) {
 550                 acpi_status wmi_status;
 551                 block = list_entry(p, struct wmi_block, list);
 552
 553                 if (memcmp(block->gblock.guid, guid_input, 16) == 0) {
 554                         if (block->handler &&
 555                             block->handler != wmi_notify_debug)
 556                                 return AE_ALREADY_ACQUIRED;
 557
 558                         block->handler = handler;
 559                         block->handler_data = data;
 560
 561                         wmi_status = wmi_method_enable(block, 1);
 562                         if ((wmi_status != AE_OK) ||
 563                             ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
 564                                 status = wmi_status;
 565                 }
 566         }
 567
 568         return status;
 569 }
 570 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 571
 572 /**
 573  * wmi_uninstall_notify_handler - Unregister handler for WMI events
 574  *
 575  * Unregister handler for events sent to the ACPI-WMI mapper device.
 576  */
 577 acpi_status wmi_remove_notify_handler(const char *guid)
 578 {
 579         struct wmi_block *block;
 580         acpi_status status = AE_NOT_EXIST;
 581         char tmp[16], guid_input[16];
 582         struct list_head *p;
 583
 584         if (!guid)
 585                 return AE_BAD_PARAMETER;
 586
 587         wmi_parse_guid(guid, tmp);
 588         wmi_swap_bytes(tmp, guid_input);
 589
 590         list_for_each(p, &wmi_block_list) {
 591                 acpi_status wmi_status;
 592                 block = list_entry(p, struct wmi_block, list);
 593
 594                 if (memcmp(block->gblock.guid, guid_input, 16) == 0) {
 595                         if (!block->handler ||
 596                             block->handler == wmi_notify_debug)
 597                                 return AE_NULL_ENTRY;
 598
 599                         if (debug_event) {
 600                                 block->handler = wmi_notify_debug;
 601                                 status = AE_OK;
 602                         } else {
 603                                 wmi_status = wmi_method_enable(block, 0);
 604                                 block->handler = NULL;
 605                                 block->handler_data = NULL;
 606                                 if ((wmi_status != AE_OK) ||
 607                                     ((wmi_status == AE_OK) &&
 608                                      (status == AE_NOT_EXIST)))
 609                                         status = wmi_status;
 610                         }
 611                 }
 612         }
 613
 614         return status;
 615 }
 616 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 617
 618 /**
 619  * wmi_get_event_data - Get WMI data associated with an event
 620  *
 621  * @event: Event to find
 622  * @out: Buffer to hold event data. out->pointer should be freed with kfree()
 623  *
 624  * Returns extra data associated with an event in WMI.
 625  */
 626 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
 627 {
 628         struct acpi_object_list input;
 629         union acpi_object params[1];
 630         struct guid_block *gblock;
 631         struct wmi_block *wblock;
 632         struct list_head *p;
 633
 634         input.count = 1;
 635         input.pointer = params;
 636         params[0].type = ACPI_TYPE_INTEGER;
 637         params[0].integer.value = event;
 638
 639         list_for_each(p, &wmi_block_list) {
 640                 wblock = list_entry(p, struct wmi_block, list);
 641                 gblock = &wblock->gblock;
 642
 643                 if ((gblock->flags & ACPI_WMI_EVENT) &&
 644                         (gblock->notify_id == event))
 645                         return acpi_evaluate_object(wblock->handle, "_WED",
 646                                 &input, out);
 647         }
 648
 649         return AE_NOT_FOUND;
 650 }
 651 EXPORT_SYMBOL_GPL(wmi_get_event_data);
 652
 653 /**
 654  * wmi_has_guid - Check if a GUID is available
 655  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 656  *
 657  * Check if a given GUID is defined by _WDG
 658  */
 659 bool wmi_has_guid(const char *guid_string)
 660 {
 661         return find_guid(guid_string, NULL);
 662 }
 663 EXPORT_SYMBOL_GPL(wmi_has_guid);
 664
 665 /*
 666  * sysfs interface
 667  */
 668 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 669                              char *buf)
 670 {
 671         char guid_string[37];
 672         struct wmi_block *wblock;
 673
 674         wblock = dev_get_drvdata(dev);
 675         if (!wblock) {
 676                 strcat(buf, "\n");
 677                 return strlen(buf);
 678         }
 679
 680         wmi_gtoa(wblock->gblock.guid, guid_string);
 681
 682         return sprintf(buf, "wmi:%s\n", guid_string);
 683 }
 684 static DEVICE_ATTR_RO(modalias);
 685
 686 static struct attribute *wmi_attrs[] = {
 687         &dev_attr_modalias.attr,
 688         NULL,
 689 };
 690 ATTRIBUTE_GROUPS(wmi);
 691
 692 static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 693 {
 694         char guid_string[37];
 695
 696         struct wmi_block *wblock;
 697
 698         if (add_uevent_var(env, "MODALIAS="))
 699                 return -ENOMEM;
 700
 701         wblock = dev_get_drvdata(dev);
 702         if (!wblock)
 703                 return -ENOMEM;
 704
 705         wmi_gtoa(wblock->gblock.guid, guid_string);
 706
 707         strcpy(&env->buf[env->buflen - 1], "wmi:");
 708         memcpy(&env->buf[env->buflen - 1 + 4], guid_string, 36);
 709         env->buflen += 40;
 710
 711         return 0;
 712 }
 713
 714 static void wmi_dev_free(struct device *dev)
 715 {
 716         struct wmi_block *wmi_block = container_of(dev, struct wmi_block, dev);
 717
 718         kfree(wmi_block);
 719 }
 720
 721 static struct class wmi_class = {
 722         .name = "wmi",
 723         .dev_release = wmi_dev_free,
 724         .dev_uevent = wmi_dev_uevent,
 725         .dev_groups = wmi_groups,
 726 };
 727
 728 static int wmi_create_device(const struct guid_block *gblock,
 729                              struct wmi_block *wblock, acpi_handle handle)
 730 {
 731         char guid_string[37];
 732
 733         wblock->dev.class = &wmi_class;
 734
 735         wmi_gtoa(gblock->guid, guid_string);
 736         dev_set_name(&wblock->dev, "%s", guid_string);
 737
 738         dev_set_drvdata(&wblock->dev, wblock);
 739
 740         return device_register(&wblock->dev);
 741 }
 742
 743 static void wmi_free_devices(void)
 744 {
 745         struct wmi_block *wblock, *next;
 746
 747         /* Delete devices for all the GUIDs */
 748         list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
 749                 list_del(&wblock->list);
 750                 if (wblock->dev.class)
 751                         device_unregister(&wblock->dev);
 752                 else
 753                         kfree(wblock);
 754         }
 755 }
 756
 757 static bool guid_already_parsed(const char *guid_string)
 758 {
 759         struct wmi_block *wblock;
 760
 761         list_for_each_entry(wblock, &wmi_block_list, list)
 762                 if (memcmp(wblock->gblock.guid, guid_string, 16) == 0)
 763                         return true;
 764
 765         return false;
 766 }
 767
 768 /*
 769  * Parse the _WDG method for the GUID data blocks
 770  */
 771 static int parse_wdg(acpi_handle handle)
 772 {
 773         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
 774         union acpi_object *obj;
 775         const struct guid_block *gblock;
 776         struct wmi_block *wblock;
 777         acpi_status status;
 778         int retval;
 779         u32 i, total;
 780
 781         status = acpi_evaluate_object(handle, "_WDG", NULL, &out);
 782         if (ACPI_FAILURE(status))
 783                 return -ENXIO;
 784
 785         obj = (union acpi_object *) out.pointer;
 786         if (!obj)
 787                 return -ENXIO;
 788
 789         if (obj->type != ACPI_TYPE_BUFFER) {
 790                 retval = -ENXIO;
 791                 goto out_free_pointer;
 792         }
 793
 794         gblock = (const struct guid_block *)obj->buffer.pointer;
 795         total = obj->buffer.length / sizeof(struct guid_block);
 796
 797         for (i = 0; i < total; i++) {
 798                 if (debug_dump_wdg)
 799                         wmi_dump_wdg(&gblock[i]);
 800
 801                 wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
 802                 if (!wblock)
 803                         return -ENOMEM;
 804
 805                 wblock->handle = handle;
 806                 wblock->gblock = gblock[i];
 807
 808                 /*
 809                   Some WMI devices, like those for nVidia hooks, have a
 810                   duplicate GUID. It's not clear what we should do in this
 811                   case yet, so for now, we'll just ignore the duplicate
 812                   for device creation.
 813                 */
 814                 if (!guid_already_parsed(gblock[i].guid)) {
 815                         retval = wmi_create_device(&gblock[i], wblock, handle);
 816                         if (retval) {
 817                                 wmi_free_devices();
 818                                 goto out_free_pointer;
 819                         }
 820                 }
 821
 822                 list_add_tail(&wblock->list, &wmi_block_list);
 823
 824                 if (debug_event) {
 825                         wblock->handler = wmi_notify_debug;
 826                         wmi_method_enable(wblock, 1);
 827                 }
 828         }
 829
 830         retval = 0;
 831
 832 out_free_pointer:
 833         kfree(out.pointer);
 834
 835         return retval;
 836 }
 837
 838 /*
 839  * WMI can have EmbeddedControl access regions. In which case, we just want to
 840  * hand these off to the EC driver.
 841  */
 842 static acpi_status
 843 acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
 844                       u32 bits, u64 *value,
 845                       void *handler_context, void *region_context)
 846 {
 847         int result = 0, i = 0;
 848         u8 temp = 0;
 849
 850         if ((address > 0xFF) || !value)
 851                 return AE_BAD_PARAMETER;
 852
 853         if (function != ACPI_READ && function != ACPI_WRITE)
 854                 return AE_BAD_PARAMETER;
 855
 856         if (bits != 8)
 857                 return AE_BAD_PARAMETER;
 858
 859         if (function == ACPI_READ) {
 860                 result = ec_read(address, &temp);
 861                 (*value) |= ((u64)temp) << i;
 862         } else {
 863                 temp = 0xff & ((*value) >> i);
 864                 result = ec_write(address, temp);
 865         }
 866
 867         switch (result) {
 868         case -EINVAL:
 869                 return AE_BAD_PARAMETER;
 870                 break;
 871         case -ENODEV:
 872                 return AE_NOT_FOUND;
 873                 break;
 874         case -ETIME:
 875                 return AE_TIME;
 876                 break;
 877         default:
 878                 return AE_OK;
 879         }
 880 }
 881
 882 static void acpi_wmi_notify(struct acpi_device *device, u32 event)
 883 {
 884         struct guid_block *block;
 885         struct wmi_block *wblock;
 886         struct list_head *p;
 887         char guid_string[37];
 888
 889         list_for_each(p, &wmi_block_list) {
 890                 wblock = list_entry(p, struct wmi_block, list);
 891                 block = &wblock->gblock;
 892
 893                 if ((block->flags & ACPI_WMI_EVENT) &&
 894                         (block->notify_id == event)) {
 895                         if (wblock->handler)
 896                                 wblock->handler(event, wblock->handler_data);
 897                         if (debug_event) {
 898                                 wmi_gtoa(wblock->gblock.guid, guid_string);
 899                                 pr_info("DEBUG Event GUID: %s\n", guid_string);
 900                         }
 901
 902                         acpi_bus_generate_netlink_event(
 903                                 device->pnp.device_class, dev_name(&device->dev),
 904                                 event, 0);
 905                         break;
 906                 }
 907         }
 908 }
 909
 910 static int acpi_wmi_remove(struct acpi_device *device)
 911 {
 912         acpi_remove_address_space_handler(device->handle,
 913                                 ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
 914         wmi_free_devices();
 915
 916         return 0;
 917 }
 918
 919 static int acpi_wmi_add(struct acpi_device *device)
 920 {
 921         acpi_status status;
 922         int error;
 923
 924         status = acpi_install_address_space_handler(device->handle,
 925                                                     ACPI_ADR_SPACE_EC,
 926                                                     &acpi_wmi_ec_space_handler,
 927                                                     NULL, NULL);
 928         if (ACPI_FAILURE(status)) {
 929                 pr_err("Error installing EC region handler\n");
 930                 return -ENODEV;
 931         }
 932
 933         error = parse_wdg(device->handle);
 934         if (error) {
 935                 acpi_remove_address_space_handler(device->handle,
 936                                                   ACPI_ADR_SPACE_EC,
 937                                                   &acpi_wmi_ec_space_handler);
 938                 pr_err("Failed to parse WDG method\n");
 939                 return error;
 940         }
 941
 942         return 0;
 943 }
 944
 945 static int __init acpi_wmi_init(void)
 946 {
 947         int error;
 948
 949         if (acpi_disabled)
 950                 return -ENODEV;
 951
 952         error = class_register(&wmi_class);
 953         if (error)
 954                 return error;
 955
 956         error = acpi_bus_register_driver(&acpi_wmi_driver);
 957         if (error) {
 958                 pr_err("Error loading mapper\n");
 959                 class_unregister(&wmi_class);
 960                 return error;
 961         }
 962
 963         pr_info("Mapper loaded\n");
 964         return 0;
 965 }
 966
 967 static void __exit acpi_wmi_exit(void)
 968 {
 969         acpi_bus_unregister_driver(&acpi_wmi_driver);
 970         class_unregister(&wmi_class);
 971
 972         pr_info("Mapper unloaded\n");
 973 }
 974
 975 subsys_initcall(acpi_wmi_init);
 976 module_exit(acpi_wmi_exit);