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