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