core.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  ACPI-WMI mapping driver
   4 *
   5 *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
   6 *
   7 *  GUID parsing code from ldm.c is:
   8 *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
   9 *   Copyright (c) 2001-2007 Anton Altaparmakov
  10 *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
  11 *
  12 *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
  13 *    Copyright (C) 2015 Andrew Lutomirski
  14 *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
  15 */
  16
  17#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
  18
  19#include <linux/acpi.h>
  20#include <linux/bits.h>
  21#include <linux/build_bug.h>
  22#include <linux/device.h>
  23#include <linux/idr.h>
  24#include <linux/init.h>
  25#include <linux/kernel.h>
  26#include <linux/module.h>
  27#include <linux/platform_device.h>
  28#include <linux/rwsem.h>
  29#include <linux/slab.h>
  30#include <linux/sysfs.h>
  31#include <linux/types.h>
  32#include <linux/uuid.h>
  33#include <linux/wmi.h>
  34#include <linux/fs.h>
  35
  36MODULE_AUTHOR("Carlos Corbacho");
  37MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  38MODULE_LICENSE("GPL");
  39
  40struct guid_block {
  41	guid_t guid;
  42	union {
  43		char object_id[2];
  44		struct {
  45			unsigned char notify_id;
  46			unsigned char reserved;
  47		};
  48	};
  49	u8 instance_count;
  50	u8 flags;
  51} __packed;
  52static_assert(sizeof(typeof_member(struct guid_block, guid)) == 16);
  53static_assert(sizeof(struct guid_block) == 20);
  54static_assert(__alignof__(struct guid_block) == 1);
  55
  56enum {	/* wmi_block flags */
  57	WMI_READ_TAKES_NO_ARGS,
  58	WMI_GUID_DUPLICATED,
  59	WMI_NO_EVENT_DATA,
  60};
  61
  62struct wmi_block {
  63	struct wmi_device dev;
  64	struct guid_block gblock;
  65	struct acpi_device *acpi_device;
  66	struct rw_semaphore notify_lock;	/* Protects notify callback add/remove */
  67	wmi_notify_handler handler;
  68	void *handler_data;
  69	bool driver_ready;
  70	unsigned long flags;
  71};
  72
  73struct wmi_guid_count_context {
  74	const guid_t *guid;
  75	int count;
  76};
  77
  78static DEFINE_IDA(wmi_ida);
  79
  80/*
  81 * If the GUID data block is marked as expensive, we must enable and
  82 * explicitily disable data collection.
  83 */
  84#define ACPI_WMI_EXPENSIVE   BIT(0)
  85#define ACPI_WMI_METHOD      BIT(1)	/* GUID is a method */
  86#define ACPI_WMI_STRING      BIT(2)	/* GUID takes & returns a string */
  87#define ACPI_WMI_EVENT       BIT(3)	/* GUID is an event */
  88
  89static const struct acpi_device_id wmi_device_ids[] = {
  90	{"PNP0C14", 0},
  91	{"pnp0c14", 0},
  92	{ }
  93};
  94MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
  95
  96#define dev_to_wblock(__dev)	container_of_const(__dev, struct wmi_block, dev.dev)
  97
  98/*
  99 * GUID parsing functions
 100 */
 101
 102static bool guid_parse_and_compare(const char *string, const guid_t *guid)
 103{
 104	guid_t guid_input;
 105
 106	if (guid_parse(string, &guid_input))
 107		return false;
 108
 109	return guid_equal(&guid_input, guid);
 110}
 111
 112static const void *find_guid_context(struct wmi_block *wblock,
 113				     struct wmi_driver *wdriver)
 114{
 115	const struct wmi_device_id *id;
 116
 117	id = wdriver->id_table;
 118	if (!id)
 119		return NULL;
 120
 121	while (*id->guid_string) {
 122		if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 123			return id->context;
 124		id++;
 125	}
 126	return NULL;
 127}
 128
 129#define WMI_ACPI_METHOD_NAME_SIZE 5
 130
 131static inline void get_acpi_method_name(const struct wmi_block *wblock,
 132					const char method,
 133					char buffer[static WMI_ACPI_METHOD_NAME_SIZE])
 134{
 135	static_assert(ARRAY_SIZE(wblock->gblock.object_id) == 2);
 136	static_assert(WMI_ACPI_METHOD_NAME_SIZE >= 5);
 137
 138	buffer[0] = 'W';
 139	buffer[1] = method;
 140	buffer[2] = wblock->gblock.object_id[0];
 141	buffer[3] = wblock->gblock.object_id[1];
 142	buffer[4] = '\0';
 143}
 144
 145static int wmidev_match_guid(struct device *dev, const void *data)
 146{
 147	struct wmi_block *wblock = dev_to_wblock(dev);
 148	const guid_t *guid = data;
 149
 150	/* Legacy GUID-based functions are restricted to only see
 151	 * a single WMI device for each GUID.
 152	 */
 153	if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags))
 154		return 0;
 155
 156	if (guid_equal(guid, &wblock->gblock.guid))
 157		return 1;
 158
 159	return 0;
 160}
 161
 162static const struct bus_type wmi_bus_type;
 163
 164static const struct device_type wmi_type_event;
 165
 166static const struct device_type wmi_type_method;
 167
 168static int wmi_device_enable(struct wmi_device *wdev, bool enable)
 169{
 170	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 171	char method[WMI_ACPI_METHOD_NAME_SIZE];
 172	acpi_handle handle;
 173	acpi_status status;
 174
 175	if (wblock->dev.dev.type == &wmi_type_method)
 176		return 0;
 177
 178	if (wblock->dev.dev.type == &wmi_type_event) {
 179		/*
 180		 * Windows always enables/disables WMI events, even when they are
 181		 * not marked as being expensive. We follow this behavior for
 182		 * compatibility reasons.
 183		 */
 184		snprintf(method, sizeof(method), "WE%02X", wblock->gblock.notify_id);
 185	} else {
 186		if (!(wblock->gblock.flags & ACPI_WMI_EXPENSIVE))
 187			return 0;
 188
 189		get_acpi_method_name(wblock, 'C', method);
 190	}
 191
 192	/*
 193	 * Not all WMI devices marked as expensive actually implement the
 194	 * necessary ACPI method. Ignore this missing ACPI method to match
 195	 * the behaviour of the Windows driver.
 196	 */
 197	status = acpi_get_handle(wblock->acpi_device->handle, method, &handle);
 198	if (ACPI_FAILURE(status))
 199		return 0;
 200
 201	status = acpi_execute_simple_method(handle, NULL, enable);
 202	if (ACPI_FAILURE(status))
 203		return -EIO;
 204
 205	return 0;
 206}
 207
 208static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
 209{
 210	struct device *dev;
 211	guid_t guid;
 212	int ret;
 213
 214	ret = guid_parse(guid_string, &guid);
 215	if (ret < 0)
 216		return ERR_PTR(ret);
 217
 218	dev = bus_find_device(&wmi_bus_type, NULL, &guid, wmidev_match_guid);
 219	if (!dev)
 220		return ERR_PTR(-ENODEV);
 221
 222	return to_wmi_device(dev);
 223}
 224
 225static void wmi_device_put(struct wmi_device *wdev)
 226{
 227	put_device(&wdev->dev);
 228}
 229
 230/*
 231 * Exported WMI functions
 232 */
 233
 234/**
 235 * wmi_instance_count - Get number of WMI object instances
 236 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 237 *
 238 * Get the number of WMI object instances.
 239 *
 240 * Returns: Number of WMI object instances or negative error code.
 241 */
 242int wmi_instance_count(const char *guid_string)
 243{
 244	struct wmi_device *wdev;
 245	int ret;
 246
 247	wdev = wmi_find_device_by_guid(guid_string);
 248	if (IS_ERR(wdev))
 249		return PTR_ERR(wdev);
 250
 251	ret = wmidev_instance_count(wdev);
 252	wmi_device_put(wdev);
 253
 254	return ret;
 255}
 256EXPORT_SYMBOL_GPL(wmi_instance_count);
 257
 258/**
 259 * wmidev_instance_count - Get number of WMI object instances
 260 * @wdev: A wmi bus device from a driver
 261 *
 262 * Get the number of WMI object instances.
 263 *
 264 * Returns: Number of WMI object instances.
 265 */
 266u8 wmidev_instance_count(struct wmi_device *wdev)
 267{
 268	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 269
 270	return wblock->gblock.instance_count;
 271}
 272EXPORT_SYMBOL_GPL(wmidev_instance_count);
 273
 274/**
 275 * wmi_evaluate_method - Evaluate a WMI method (deprecated)
 276 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 277 * @instance: Instance index
 278 * @method_id: Method ID to call
 279 * @in: Mandatory buffer containing input for the method call
 280 * @out: Empty buffer to return the method results
 281 *
 282 * Call an ACPI-WMI method, the caller must free @out.
 283 *
 284 * Return: acpi_status signaling success or error.
 285 */
 286acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id,
 287				const struct acpi_buffer *in, struct acpi_buffer *out)
 288{
 289	struct wmi_device *wdev;
 290	acpi_status status;
 291
 292	wdev = wmi_find_device_by_guid(guid_string);
 293	if (IS_ERR(wdev))
 294		return AE_ERROR;
 295
 296	status = wmidev_evaluate_method(wdev, instance, method_id, in, out);
 297
 298	wmi_device_put(wdev);
 299
 300	return status;
 301}
 302EXPORT_SYMBOL_GPL(wmi_evaluate_method);
 303
 304/**
 305 * wmidev_evaluate_method - Evaluate a WMI method
 306 * @wdev: A wmi bus device from a driver
 307 * @instance: Instance index
 308 * @method_id: Method ID to call
 309 * @in: Mandatory buffer containing input for the method call
 310 * @out: Empty buffer to return the method results
 311 *
 312 * Call an ACPI-WMI method, the caller must free @out.
 313 *
 314 * Return: acpi_status signaling success or error.
 315 */
 316acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id,
 317				   const struct acpi_buffer *in, struct acpi_buffer *out)
 318{
 319	struct guid_block *block;
 320	struct wmi_block *wblock;
 321	acpi_handle handle;
 322	struct acpi_object_list input;
 323	union acpi_object params[3];
 324	char method[WMI_ACPI_METHOD_NAME_SIZE];
 325
 326	wblock = container_of(wdev, struct wmi_block, dev);
 327	block = &wblock->gblock;
 328	handle = wblock->acpi_device->handle;
 329
 330	if (!in)
 331		return AE_BAD_DATA;
 332
 333	if (!(block->flags & ACPI_WMI_METHOD))
 334		return AE_BAD_DATA;
 335
 336	if (block->instance_count <= instance)
 337		return AE_BAD_PARAMETER;
 338
 339	input.count = 3;
 340	input.pointer = params;
 341
 342	params[0].type = ACPI_TYPE_INTEGER;
 343	params[0].integer.value = instance;
 344	params[1].type = ACPI_TYPE_INTEGER;
 345	params[1].integer.value = method_id;
 346
 347	if (wblock->gblock.flags & ACPI_WMI_STRING) {
 348		params[2].type = ACPI_TYPE_STRING;
 349		params[2].string.length = in->length;
 350		params[2].string.pointer = in->pointer;
 351	} else {
 352		params[2].type = ACPI_TYPE_BUFFER;
 353		params[2].buffer.length = in->length;
 354		params[2].buffer.pointer = in->pointer;
 355	}
 356
 357	get_acpi_method_name(wblock, 'M', method);
 358
 359	return acpi_evaluate_object(handle, method, &input, out);
 360}
 361EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
 362
 363static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
 364				 struct acpi_buffer *out)
 365{
 366	struct guid_block *block;
 367	acpi_handle handle;
 368	struct acpi_object_list input;
 369	union acpi_object wq_params[1];
 370	char method[WMI_ACPI_METHOD_NAME_SIZE];
 371
 372	if (!out)
 373		return AE_BAD_PARAMETER;
 374
 375	block = &wblock->gblock;
 376	handle = wblock->acpi_device->handle;
 377
 378	if (block->instance_count <= instance)
 379		return AE_BAD_PARAMETER;
 380
 381	/* Check GUID is a data block */
 382	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 383		return AE_ERROR;
 384
 385	input.count = 1;
 386	input.pointer = wq_params;
 387	wq_params[0].type = ACPI_TYPE_INTEGER;
 388	wq_params[0].integer.value = instance;
 389
 390	if (instance == 0 && test_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags))
 391		input.count = 0;
 392
 393	get_acpi_method_name(wblock, 'Q', method);
 394
 395	return acpi_evaluate_object(handle, method, &input, out);
 396}
 397
 398/**
 399 * wmi_query_block - Return contents of a WMI block (deprecated)
 400 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 401 * @instance: Instance index
 402 * @out: Empty buffer to return the contents of the data block to
 403 *
 404 * Query a ACPI-WMI block, the caller must free @out.
 405 *
 406 * Return: ACPI object containing the content of the WMI block.
 407 */
 408acpi_status wmi_query_block(const char *guid_string, u8 instance,
 409			    struct acpi_buffer *out)
 410{
 411	struct wmi_block *wblock;
 412	struct wmi_device *wdev;
 413	acpi_status status;
 414
 415	wdev = wmi_find_device_by_guid(guid_string);
 416	if (IS_ERR(wdev))
 417		return AE_ERROR;
 418
 419	if (wmi_device_enable(wdev, true) < 0)
 420		dev_warn(&wdev->dev, "Failed to enable device\n");
 421
 422	wblock = container_of(wdev, struct wmi_block, dev);
 423	status = __query_block(wblock, instance, out);
 424
 425	if (wmi_device_enable(wdev, false) < 0)
 426		dev_warn(&wdev->dev, "Failed to disable device\n");
 427
 428	wmi_device_put(wdev);
 429
 430	return status;
 431}
 432EXPORT_SYMBOL_GPL(wmi_query_block);
 433
 434/**
 435 * wmidev_block_query - Return contents of a WMI block
 436 * @wdev: A wmi bus device from a driver
 437 * @instance: Instance index
 438 *
 439 * Query an ACPI-WMI block, the caller must free the result.
 440 *
 441 * Return: ACPI object containing the content of the WMI block.
 442 */
 443union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
 444{
 445	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
 446	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 447
 448	if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
 449		return NULL;
 450
 451	return out.pointer;
 452}
 453EXPORT_SYMBOL_GPL(wmidev_block_query);
 454
 455/**
 456 * wmi_set_block - Write to a WMI block (deprecated)
 457 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 458 * @instance: Instance index
 459 * @in: Buffer containing new values for the data block
 460 *
 461 * Write the contents of the input buffer to an ACPI-WMI data block.
 462 *
 463 * Return: acpi_status signaling success or error.
 464 */
 465acpi_status wmi_set_block(const char *guid_string, u8 instance, const struct acpi_buffer *in)
 466{
 467	struct wmi_device *wdev;
 468	acpi_status status;
 469
 470	wdev = wmi_find_device_by_guid(guid_string);
 471	if (IS_ERR(wdev))
 472		return AE_ERROR;
 473
 474	if (wmi_device_enable(wdev, true) < 0)
 475		dev_warn(&wdev->dev, "Failed to enable device\n");
 476
 477	status =  wmidev_block_set(wdev, instance, in);
 478
 479	if (wmi_device_enable(wdev, false) < 0)
 480		dev_warn(&wdev->dev, "Failed to disable device\n");
 481
 482	wmi_device_put(wdev);
 483
 484	return status;
 485}
 486EXPORT_SYMBOL_GPL(wmi_set_block);
 487
 488/**
 489 * wmidev_block_set - Write to a WMI block
 490 * @wdev: A wmi bus device from a driver
 491 * @instance: Instance index
 492 * @in: Buffer containing new values for the data block
 493 *
 494 * Write contents of the input buffer to an ACPI-WMI data block.
 495 *
 496 * Return: acpi_status signaling success or error.
 497 */
 498acpi_status wmidev_block_set(struct wmi_device *wdev, u8 instance, const struct acpi_buffer *in)
 499{
 500	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 501	acpi_handle handle = wblock->acpi_device->handle;
 502	struct guid_block *block = &wblock->gblock;
 503	char method[WMI_ACPI_METHOD_NAME_SIZE];
 504	struct acpi_object_list input;
 505	union acpi_object params[2];
 506
 507	if (!in)
 508		return AE_BAD_DATA;
 509
 510	if (block->instance_count <= instance)
 511		return AE_BAD_PARAMETER;
 512
 513	/* Check GUID is a data block */
 514	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 515		return AE_ERROR;
 516
 517	input.count = 2;
 518	input.pointer = params;
 519	params[0].type = ACPI_TYPE_INTEGER;
 520	params[0].integer.value = instance;
 521
 522	if (wblock->gblock.flags & ACPI_WMI_STRING) {
 523		params[1].type = ACPI_TYPE_STRING;
 524		params[1].string.length = in->length;
 525		params[1].string.pointer = in->pointer;
 526	} else {
 527		params[1].type = ACPI_TYPE_BUFFER;
 528		params[1].buffer.length = in->length;
 529		params[1].buffer.pointer = in->pointer;
 530	}
 531
 532	get_acpi_method_name(wblock, 'S', method);
 533
 534	return acpi_evaluate_object(handle, method, &input, NULL);
 535}
 536EXPORT_SYMBOL_GPL(wmidev_block_set);
 537
 538/**
 539 * wmi_install_notify_handler - Register handler for WMI events (deprecated)
 540 * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 541 * @handler: Function to handle notifications
 542 * @data: Data to be returned to handler when event is fired
 543 *
 544 * Register a handler for events sent to the ACPI-WMI mapper device.
 545 *
 546 * Return: acpi_status signaling success or error.
 547 */
 548acpi_status wmi_install_notify_handler(const char *guid,
 549				       wmi_notify_handler handler,
 550				       void *data)
 551{
 552	struct wmi_block *wblock;
 553	struct wmi_device *wdev;
 554	acpi_status status;
 555
 556	wdev = wmi_find_device_by_guid(guid);
 557	if (IS_ERR(wdev))
 558		return AE_ERROR;
 559
 560	wblock = container_of(wdev, struct wmi_block, dev);
 561
 562	down_write(&wblock->notify_lock);
 563	if (wblock->handler) {
 564		status = AE_ALREADY_ACQUIRED;
 565	} else {
 566		wblock->handler = handler;
 567		wblock->handler_data = data;
 568
 569		if (wmi_device_enable(wdev, true) < 0)
 570			dev_warn(&wblock->dev.dev, "Failed to enable device\n");
 571
 572		status = AE_OK;
 573	}
 574	up_write(&wblock->notify_lock);
 575
 576	wmi_device_put(wdev);
 577
 578	return status;
 579}
 580EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 581
 582/**
 583 * wmi_remove_notify_handler - Unregister handler for WMI events (deprecated)
 584 * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 585 *
 586 * Unregister handler for events sent to the ACPI-WMI mapper device.
 587 *
 588 * Return: acpi_status signaling success or error.
 589 */
 590acpi_status wmi_remove_notify_handler(const char *guid)
 591{
 592	struct wmi_block *wblock;
 593	struct wmi_device *wdev;
 594	acpi_status status;
 595
 596	wdev = wmi_find_device_by_guid(guid);
 597	if (IS_ERR(wdev))
 598		return AE_ERROR;
 599
 600	wblock = container_of(wdev, struct wmi_block, dev);
 601
 602	down_write(&wblock->notify_lock);
 603	if (!wblock->handler) {
 604		status = AE_NULL_ENTRY;
 605	} else {
 606		if (wmi_device_enable(wdev, false) < 0)
 607			dev_warn(&wblock->dev.dev, "Failed to disable device\n");
 608
 609		wblock->handler = NULL;
 610		wblock->handler_data = NULL;
 611
 612		status = AE_OK;
 613	}
 614	up_write(&wblock->notify_lock);
 615
 616	wmi_device_put(wdev);
 617
 618	return status;
 619}
 620EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 621
 622/**
 623 * wmi_has_guid - Check if a GUID is available
 624 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 625 *
 626 * Check if a given GUID is defined by _WDG.
 627 *
 628 * Return: True if GUID is available, false otherwise.
 629 */
 630bool wmi_has_guid(const char *guid_string)
 631{
 632	struct wmi_device *wdev;
 633
 634	wdev = wmi_find_device_by_guid(guid_string);
 635	if (IS_ERR(wdev))
 636		return false;
 637
 638	wmi_device_put(wdev);
 639
 640	return true;
 641}
 642EXPORT_SYMBOL_GPL(wmi_has_guid);
 643
 644/**
 645 * wmi_get_acpi_device_uid() - Get _UID name of ACPI device that defines GUID (deprecated)
 646 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 647 *
 648 * Find the _UID of ACPI device associated with this WMI GUID.
 649 *
 650 * Return: The ACPI _UID field value or NULL if the WMI GUID was not found.
 651 */
 652char *wmi_get_acpi_device_uid(const char *guid_string)
 653{
 654	struct wmi_block *wblock;
 655	struct wmi_device *wdev;
 656	char *uid;
 657
 658	wdev = wmi_find_device_by_guid(guid_string);
 659	if (IS_ERR(wdev))
 660		return NULL;
 661
 662	wblock = container_of(wdev, struct wmi_block, dev);
 663	uid = acpi_device_uid(wblock->acpi_device);
 664
 665	wmi_device_put(wdev);
 666
 667	return uid;
 668}
 669EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);
 670
 671/*
 672 * sysfs interface
 673 */
 674static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 675			     char *buf)
 676{
 677	struct wmi_block *wblock = dev_to_wblock(dev);
 678
 679	return sysfs_emit(buf, "wmi:%pUL\n", &wblock->gblock.guid);
 680}
 681static DEVICE_ATTR_RO(modalias);
 682
 683static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
 684			 char *buf)
 685{
 686	struct wmi_block *wblock = dev_to_wblock(dev);
 687
 688	return sysfs_emit(buf, "%pUL\n", &wblock->gblock.guid);
 689}
 690static DEVICE_ATTR_RO(guid);
 691
 692static ssize_t instance_count_show(struct device *dev,
 693				   struct device_attribute *attr, char *buf)
 694{
 695	struct wmi_block *wblock = dev_to_wblock(dev);
 696
 697	return sysfs_emit(buf, "%d\n", (int)wblock->gblock.instance_count);
 698}
 699static DEVICE_ATTR_RO(instance_count);
 700
 701static ssize_t expensive_show(struct device *dev,
 702			      struct device_attribute *attr, char *buf)
 703{
 704	struct wmi_block *wblock = dev_to_wblock(dev);
 705
 706	return sysfs_emit(buf, "%d\n",
 707			  (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
 708}
 709static DEVICE_ATTR_RO(expensive);
 710
 711static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr,
 712				    char *buf)
 713{
 714	struct wmi_device *wdev = to_wmi_device(dev);
 715	ssize_t ret;
 716
 717	device_lock(dev);
 718	ret = sysfs_emit(buf, "%s\n", wdev->driver_override);
 719	device_unlock(dev);
 720
 721	return ret;
 722}
 723
 724static ssize_t driver_override_store(struct device *dev, struct device_attribute *attr,
 725				     const char *buf, size_t count)
 726{
 727	struct wmi_device *wdev = to_wmi_device(dev);
 728	int ret;
 729
 730	ret = driver_set_override(dev, &wdev->driver_override, buf, count);
 731	if (ret < 0)
 732		return ret;
 733
 734	return count;
 735}
 736static DEVICE_ATTR_RW(driver_override);
 737
 738static struct attribute *wmi_attrs[] = {
 739	&dev_attr_modalias.attr,
 740	&dev_attr_guid.attr,
 741	&dev_attr_instance_count.attr,
 742	&dev_attr_expensive.attr,
 743	&dev_attr_driver_override.attr,
 744	NULL
 745};
 746ATTRIBUTE_GROUPS(wmi);
 747
 748static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
 749			      char *buf)
 750{
 751	struct wmi_block *wblock = dev_to_wblock(dev);
 752
 753	return sysfs_emit(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
 754}
 755static DEVICE_ATTR_RO(notify_id);
 756
 757static struct attribute *wmi_event_attrs[] = {
 758	&dev_attr_notify_id.attr,
 759	NULL
 760};
 761ATTRIBUTE_GROUPS(wmi_event);
 762
 763static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
 764			      char *buf)
 765{
 766	struct wmi_block *wblock = dev_to_wblock(dev);
 767
 768	return sysfs_emit(buf, "%c%c\n", wblock->gblock.object_id[0],
 769			  wblock->gblock.object_id[1]);
 770}
 771static DEVICE_ATTR_RO(object_id);
 772
 773static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
 774			    char *buf)
 775{
 776	struct wmi_device *wdev = to_wmi_device(dev);
 777
 778	return sysfs_emit(buf, "%d\n", (int)wdev->setable);
 779}
 780static DEVICE_ATTR_RO(setable);
 781
 782static struct attribute *wmi_data_attrs[] = {
 783	&dev_attr_object_id.attr,
 784	&dev_attr_setable.attr,
 785	NULL
 786};
 787ATTRIBUTE_GROUPS(wmi_data);
 788
 789static struct attribute *wmi_method_attrs[] = {
 790	&dev_attr_object_id.attr,
 791	NULL
 792};
 793ATTRIBUTE_GROUPS(wmi_method);
 794
 795static int wmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
 796{
 797	const struct wmi_block *wblock = dev_to_wblock(dev);
 798
 799	if (add_uevent_var(env, "MODALIAS=wmi:%pUL", &wblock->gblock.guid))
 800		return -ENOMEM;
 801
 802	if (add_uevent_var(env, "WMI_GUID=%pUL", &wblock->gblock.guid))
 803		return -ENOMEM;
 804
 805	return 0;
 806}
 807
 808static void wmi_dev_release(struct device *dev)
 809{
 810	struct wmi_block *wblock = dev_to_wblock(dev);
 811
 812	kfree(wblock->dev.driver_override);
 813	kfree(wblock);
 814}
 815
 816static int wmi_dev_match(struct device *dev, const struct device_driver *driver)
 817{
 818	const struct wmi_driver *wmi_driver = to_wmi_driver(driver);
 819	struct wmi_block *wblock = dev_to_wblock(dev);
 820	const struct wmi_device_id *id = wmi_driver->id_table;
 821
 822	/* When driver_override is set, only bind to the matching driver */
 823	if (wblock->dev.driver_override)
 824		return !strcmp(wblock->dev.driver_override, driver->name);
 825
 826	if (id == NULL)
 827		return 0;
 828
 829	while (*id->guid_string) {
 830		if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 831			return 1;
 832
 833		id++;
 834	}
 835
 836	return 0;
 837}
 838
 839static void wmi_dev_disable(void *data)
 840{
 841	struct device *dev = data;
 842
 843	if (wmi_device_enable(to_wmi_device(dev), false) < 0)
 844		dev_warn(dev, "Failed to disable device\n");
 845}
 846
 847static int wmi_dev_probe(struct device *dev)
 848{
 849	struct wmi_block *wblock = dev_to_wblock(dev);
 850	struct wmi_driver *wdriver = to_wmi_driver(dev->driver);
 851	int ret;
 852
 853	/* Some older WMI drivers will break if instantiated multiple times,
 854	 * so they are blocked from probing WMI devices with a duplicated GUID.
 855	 *
 856	 * New WMI drivers should support being instantiated multiple times.
 857	 */
 858	if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags) && !wdriver->no_singleton) {
 859		dev_warn(dev, "Legacy driver %s cannot be instantiated multiple times\n",
 860			 dev->driver->name);
 861
 862		return -ENODEV;
 863	}
 864
 865	if (wdriver->notify) {
 866		if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags) && !wdriver->no_notify_data)
 867			return -ENODEV;
 868	}
 869
 870	if (wmi_device_enable(to_wmi_device(dev), true) < 0)
 871		dev_warn(dev, "failed to enable device -- probing anyway\n");
 872
 873	/*
 874	 * We have to make sure that all devres-managed resources are released first because
 875	 * some might still want to access the underlying WMI device.
 876	 */
 877	ret = devm_add_action_or_reset(dev, wmi_dev_disable, dev);
 878	if (ret < 0)
 879		return ret;
 880
 881	if (wdriver->probe) {
 882		ret = wdriver->probe(to_wmi_device(dev),
 883				find_guid_context(wblock, wdriver));
 884		if (ret)
 885			return ret;
 886	}
 887
 888	down_write(&wblock->notify_lock);
 889	wblock->driver_ready = true;
 890	up_write(&wblock->notify_lock);
 891
 892	return 0;
 893}
 894
 895static void wmi_dev_remove(struct device *dev)
 896{
 897	struct wmi_block *wblock = dev_to_wblock(dev);
 898	struct wmi_driver *wdriver = to_wmi_driver(dev->driver);
 899
 900	down_write(&wblock->notify_lock);
 901	wblock->driver_ready = false;
 902	up_write(&wblock->notify_lock);
 903
 904	if (wdriver->remove)
 905		wdriver->remove(to_wmi_device(dev));
 906}
 907
 908static void wmi_dev_shutdown(struct device *dev)
 909{
 910	struct wmi_driver *wdriver;
 911	struct wmi_block *wblock;
 912
 913	if (dev->driver) {
 914		wdriver = to_wmi_driver(dev->driver);
 915		wblock = dev_to_wblock(dev);
 916
 917		/*
 918		 * Some machines return bogus WMI event data when disabling
 919		 * the WMI event. Because of this we must prevent the associated
 920		 * WMI driver from receiving new WMI events before disabling it.
 921		 */
 922		down_write(&wblock->notify_lock);
 923		wblock->driver_ready = false;
 924		up_write(&wblock->notify_lock);
 925
 926		if (wdriver->shutdown)
 927			wdriver->shutdown(to_wmi_device(dev));
 928
 929		/*
 930		 * We still need to disable the WMI device here since devres-managed resources
 931		 * like wmi_dev_disable() will not be release during shutdown.
 932		 */
 933		if (wmi_device_enable(to_wmi_device(dev), false) < 0)
 934			dev_warn(dev, "Failed to disable device\n");
 935	}
 936}
 937
 938static struct class wmi_bus_class = {
 939	.name = "wmi_bus",
 940};
 941
 942static const struct bus_type wmi_bus_type = {
 943	.name = "wmi",
 944	.dev_groups = wmi_groups,
 945	.match = wmi_dev_match,
 946	.uevent = wmi_dev_uevent,
 947	.probe = wmi_dev_probe,
 948	.remove = wmi_dev_remove,
 949	.shutdown = wmi_dev_shutdown,
 950};
 951
 952static const struct device_type wmi_type_event = {
 953	.name = "event",
 954	.groups = wmi_event_groups,
 955	.release = wmi_dev_release,
 956};
 957
 958static const struct device_type wmi_type_method = {
 959	.name = "method",
 960	.groups = wmi_method_groups,
 961	.release = wmi_dev_release,
 962};
 963
 964static const struct device_type wmi_type_data = {
 965	.name = "data",
 966	.groups = wmi_data_groups,
 967	.release = wmi_dev_release,
 968};
 969
 970static int wmi_count_guids(struct device *dev, void *data)
 971{
 972	struct wmi_guid_count_context *context = data;
 973	struct wmi_block *wblock = dev_to_wblock(dev);
 974
 975	if (guid_equal(&wblock->gblock.guid, context->guid))
 976		context->count++;
 977
 978	return 0;
 979}
 980
 981static int guid_count(const guid_t *guid)
 982{
 983	struct wmi_guid_count_context context = {
 984		.guid = guid,
 985		.count = 0,
 986	};
 987	int ret;
 988
 989	ret = bus_for_each_dev(&wmi_bus_type, NULL, &context, wmi_count_guids);
 990	if (ret < 0)
 991		return ret;
 992
 993	return context.count;
 994}
 995
 996static int wmi_dev_set_name(struct wmi_block *wblock, int count)
 997{
 998	if (IS_ENABLED(CONFIG_ACPI_WMI_LEGACY_DEVICE_NAMES)) {
 999		if (count)
1000			return dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid,
1001					    count);
1002		else
1003			return dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid);
1004	}
1005
1006	return dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, wblock->dev.dev.id);
1007}
1008
1009static int wmi_create_device(struct device *wmi_bus_dev,
1010			     struct wmi_block *wblock,
1011			     struct acpi_device *device)
1012{
1013	char method[WMI_ACPI_METHOD_NAME_SIZE];
1014	struct acpi_device_info *info;
1015	acpi_handle method_handle;
1016	acpi_status status;
1017	int count, ret;
1018
1019	if (wblock->gblock.flags & ACPI_WMI_EVENT) {
1020		wblock->dev.dev.type = &wmi_type_event;
1021		goto out_init;
1022	}
1023
1024	if (wblock->gblock.flags & ACPI_WMI_METHOD) {
1025		get_acpi_method_name(wblock, 'M', method);
1026		if (!acpi_has_method(device->handle, method)) {
1027			dev_warn(wmi_bus_dev,
1028				 FW_BUG "%s method block execution control method not found\n",
1029				 method);
1030
1031			return -ENXIO;
1032		}
1033
1034		wblock->dev.dev.type = &wmi_type_method;
1035		goto out_init;
1036	}
1037
1038	/*
1039	 * Data Block Query Control Method (WQxx by convention) is
1040	 * required per the WMI documentation. If it is not present,
1041	 * we ignore this data block.
1042	 */
1043	get_acpi_method_name(wblock, 'Q', method);
1044	status = acpi_get_handle(device->handle, method, &method_handle);
1045	if (ACPI_FAILURE(status)) {
1046		dev_warn(wmi_bus_dev,
1047			 FW_BUG "%s data block query control method not found\n",
1048			 method);
1049
1050		return -ENXIO;
1051	}
1052
1053	status = acpi_get_object_info(method_handle, &info);
1054	if (ACPI_FAILURE(status))
1055		return -EIO;
1056
1057	wblock->dev.dev.type = &wmi_type_data;
1058
1059	/*
1060	 * The Microsoft documentation specifically states:
1061	 *
1062	 *   Data blocks registered with only a single instance
1063	 *   can ignore the parameter.
1064	 *
1065	 * ACPICA will get mad at us if we call the method with the wrong number
1066	 * of arguments, so check what our method expects.  (On some Dell
1067	 * laptops, WQxx may not be a method at all.)
1068	 */
1069	if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
1070		set_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags);
1071
1072	kfree(info);
1073
1074	get_acpi_method_name(wblock, 'S', method);
1075	if (acpi_has_method(device->handle, method))
1076		wblock->dev.setable = true;
1077
1078 out_init:
1079	init_rwsem(&wblock->notify_lock);
1080	wblock->driver_ready = false;
1081	wblock->dev.dev.bus = &wmi_bus_type;
1082	wblock->dev.dev.parent = wmi_bus_dev;
1083
1084	count = guid_count(&wblock->gblock.guid);
1085	if (count < 0)
1086		return count;
1087
1088	if (count)
1089		set_bit(WMI_GUID_DUPLICATED, &wblock->flags);
1090
1091	ret = ida_alloc(&wmi_ida, GFP_KERNEL);
1092	if (ret < 0)
1093		return ret;
1094
1095	wblock->dev.dev.id = ret;
1096	ret = wmi_dev_set_name(wblock, count);
1097	if (ret < 0) {
1098		ida_free(&wmi_ida, wblock->dev.dev.id);
1099		return ret;
1100	}
1101
1102	device_initialize(&wblock->dev.dev);
1103
1104	return 0;
1105}
1106
1107static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
1108{
1109	struct device_link *link;
1110
1111	/*
1112	 * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
1113	 * are unable to find a WMI device during probe, instead they require
1114	 * all WMI devices associated with an platform device to become available
1115	 * at once. This device link thus prevents WMI drivers from probing until
1116	 * the associated platform device has finished probing (and has registered
1117	 * all discovered WMI devices).
1118	 */
1119
1120	link = device_link_add(&wdev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
1121	if (!link)
1122		return -EINVAL;
1123
1124	return device_add(&wdev->dev);
1125}
1126
1127/*
1128 * Parse the _WDG method for the GUID data blocks
1129 */
1130static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
1131{
1132	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
1133	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
1134	const struct guid_block *gblock;
1135	bool event_data_available;
1136	struct wmi_block *wblock;
1137	union acpi_object *obj;
1138	acpi_status status;
1139	u32 i, total;
1140	int retval;
1141
1142	status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
1143	if (ACPI_FAILURE(status))
1144		return -ENXIO;
1145
1146	obj = out.pointer;
1147	if (!obj)
1148		return -ENXIO;
1149
1150	if (obj->type != ACPI_TYPE_BUFFER) {
1151		kfree(obj);
1152		return -ENXIO;
1153	}
1154
1155	event_data_available = acpi_has_method(device->handle, "_WED");
1156	gblock = (const struct guid_block *)obj->buffer.pointer;
1157	total = obj->buffer.length / sizeof(struct guid_block);
1158
1159	for (i = 0; i < total; i++) {
1160		if (!gblock[i].instance_count) {
1161			dev_info(wmi_bus_dev, FW_INFO "%pUL has zero instances\n", &gblock[i].guid);
1162			continue;
1163		}
1164
1165		wblock = kzalloc(sizeof(*wblock), GFP_KERNEL);
1166		if (!wblock)
1167			continue;
1168
1169		wblock->acpi_device = device;
1170		wblock->gblock = gblock[i];
1171		if (gblock[i].flags & ACPI_WMI_EVENT && !event_data_available)
1172			set_bit(WMI_NO_EVENT_DATA, &wblock->flags);
1173
1174		retval = wmi_create_device(wmi_bus_dev, wblock, device);
1175		if (retval) {
1176			kfree(wblock);
1177			continue;
1178		}
1179
1180		retval = wmi_add_device(pdev, &wblock->dev);
1181		if (retval) {
1182			dev_err(wmi_bus_dev, "failed to register %pUL\n",
1183				&wblock->gblock.guid);
1184
1185			ida_free(&wmi_ida, wblock->dev.dev.id);
1186			put_device(&wblock->dev.dev);
1187		}
1188	}
1189
1190	kfree(obj);
1191
1192	return 0;
1193}
1194
1195static int wmi_get_notify_data(struct wmi_block *wblock, union acpi_object **obj)
1196{
1197	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
1198	union acpi_object param = {
1199		.integer = {
1200			.type = ACPI_TYPE_INTEGER,
1201			.value = wblock->gblock.notify_id,
1202		}
1203	};
1204	struct acpi_object_list input = {
1205		.count = 1,
1206		.pointer = &param,
1207	};
1208	acpi_status status;
1209
1210	status = acpi_evaluate_object(wblock->acpi_device->handle, "_WED", &input, &data);
1211	if (ACPI_FAILURE(status)) {
1212		dev_warn(&wblock->dev.dev, "Failed to get event data\n");
1213		return -EIO;
1214	}
1215
1216	*obj = data.pointer;
1217
1218	return 0;
1219}
1220
1221static void wmi_notify_driver(struct wmi_block *wblock, union acpi_object *obj)
1222{
1223	struct wmi_driver *driver = to_wmi_driver(wblock->dev.dev.driver);
1224
1225	if (!obj && !driver->no_notify_data) {
1226		dev_warn(&wblock->dev.dev, "Event contains no event data\n");
1227		return;
1228	}
1229
1230	if (driver->notify)
1231		driver->notify(&wblock->dev, obj);
1232}
1233
1234static int wmi_notify_device(struct device *dev, void *data)
1235{
1236	struct wmi_block *wblock = dev_to_wblock(dev);
1237	union acpi_object *obj = NULL;
1238	u32 *event = data;
1239	int ret;
1240
1241	if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
1242		return 0;
1243
1244	/* The ACPI WMI specification says that _WED should be
1245	 * evaluated every time an notification is received, even
1246	 * if no consumers are present.
1247	 *
1248	 * Some firmware implementations actually depend on this
1249	 * by using a queue for events which will fill up if the
1250	 * WMI driver core stops evaluating _WED due to missing
1251	 * WMI event consumers.
1252	 */
1253	if (!test_bit(WMI_NO_EVENT_DATA, &wblock->flags)) {
1254		ret = wmi_get_notify_data(wblock, &obj);
1255		if (ret < 0)
1256			return -EIO;
1257	}
1258
1259	down_read(&wblock->notify_lock);
1260
1261	if (wblock->dev.dev.driver && wblock->driver_ready)
1262		wmi_notify_driver(wblock, obj);
1263
1264	if (wblock->handler)
1265		wblock->handler(obj, wblock->handler_data);
1266
1267	up_read(&wblock->notify_lock);
1268
1269	kfree(obj);
1270
1271	acpi_bus_generate_netlink_event("wmi", acpi_dev_name(wblock->acpi_device), *event, 0);
1272
1273	return -EBUSY;
1274}
1275
1276static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context)
1277{
1278	struct device *wmi_bus_dev = context;
1279
1280	device_for_each_child(wmi_bus_dev, &event, wmi_notify_device);
1281}
1282
1283static int wmi_remove_device(struct device *dev, void *data)
1284{
1285	int id = dev->id;
1286
1287	device_unregister(dev);
1288	ida_free(&wmi_ida, id);
1289
1290	return 0;
1291}
1292
1293static void acpi_wmi_remove(struct platform_device *device)
1294{
1295	struct device *wmi_bus_device = dev_get_drvdata(&device->dev);
1296
1297	device_for_each_child_reverse(wmi_bus_device, NULL, wmi_remove_device);
1298}
1299
1300static void acpi_wmi_remove_notify_handler(void *data)
1301{
1302	struct acpi_device *acpi_device = data;
1303
1304	acpi_remove_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY, acpi_wmi_notify_handler);
1305}
1306
1307static void acpi_wmi_remove_bus_device(void *data)
1308{
1309	struct device *wmi_bus_dev = data;
1310
1311	device_unregister(wmi_bus_dev);
1312}
1313
1314static int acpi_wmi_probe(struct platform_device *device)
1315{
1316	struct acpi_device *acpi_device;
1317	struct device *wmi_bus_dev;
1318	acpi_status status;
1319	int error;
1320
1321	acpi_device = ACPI_COMPANION(&device->dev);
1322	if (!acpi_device) {
1323		dev_err(&device->dev, "ACPI companion is missing\n");
1324		return -ENODEV;
1325	}
1326
1327	wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0), NULL, "wmi_bus-%s",
1328				    dev_name(&device->dev));
1329	if (IS_ERR(wmi_bus_dev))
1330		return PTR_ERR(wmi_bus_dev);
1331
1332	error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_bus_device, wmi_bus_dev);
1333	if (error < 0)
1334		return error;
1335
1336	dev_set_drvdata(&device->dev, wmi_bus_dev);
1337
1338	status = acpi_install_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY,
1339					     acpi_wmi_notify_handler, wmi_bus_dev);
1340	if (ACPI_FAILURE(status)) {
1341		dev_err(&device->dev, "Error installing notify handler\n");
1342		return -ENODEV;
1343	}
1344	error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_notify_handler,
1345					 acpi_device);
1346	if (error < 0)
1347		return error;
1348
1349	error = parse_wdg(wmi_bus_dev, device);
1350	if (error) {
1351		dev_err(&device->dev, "Failed to parse _WDG method\n");
1352		return error;
1353	}
1354
1355	return 0;
1356}
1357
1358int __must_check __wmi_driver_register(struct wmi_driver *driver,
1359				       struct module *owner)
1360{
1361	driver->driver.owner = owner;
1362	driver->driver.bus = &wmi_bus_type;
1363
1364	return driver_register(&driver->driver);
1365}
1366EXPORT_SYMBOL(__wmi_driver_register);
1367
1368/**
1369 * wmi_driver_unregister() - Unregister a WMI driver
1370 * @driver: WMI driver to unregister
1371 *
1372 * Unregisters a WMI driver from the WMI bus.
1373 */
1374void wmi_driver_unregister(struct wmi_driver *driver)
1375{
1376	driver_unregister(&driver->driver);
1377}
1378EXPORT_SYMBOL(wmi_driver_unregister);
1379
1380static struct platform_driver acpi_wmi_driver = {
1381	.driver = {
1382		.name = "acpi-wmi",
1383		.acpi_match_table = wmi_device_ids,
1384	},
1385	.probe = acpi_wmi_probe,
1386	.remove = acpi_wmi_remove,
1387};
1388
1389static int __init acpi_wmi_init(void)
1390{
1391	int error;
1392
1393	if (acpi_disabled)
1394		return -ENODEV;
1395
1396	error = class_register(&wmi_bus_class);
1397	if (error)
1398		return error;
1399
1400	error = bus_register(&wmi_bus_type);
1401	if (error)
1402		goto err_unreg_class;
1403
1404	error = platform_driver_register(&acpi_wmi_driver);
1405	if (error) {
1406		pr_err("Error loading mapper\n");
1407		goto err_unreg_bus;
1408	}
1409
1410	return 0;
1411
1412err_unreg_bus:
1413	bus_unregister(&wmi_bus_type);
1414
1415err_unreg_class:
1416	class_unregister(&wmi_bus_class);
1417
1418	return error;
1419}
1420
1421static void __exit acpi_wmi_exit(void)
1422{
1423	platform_driver_unregister(&acpi_wmi_driver);
1424	bus_unregister(&wmi_bus_type);
1425	class_unregister(&wmi_bus_class);
1426}
1427
1428subsys_initcall_sync(acpi_wmi_init);
1429module_exit(acpi_wmi_exit);