wmi.c 35.6 KB
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/*
 *  ACPI-WMI mapping driver
 *
 *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
 *
 *  GUID parsing code from ldm.c is:
 *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
 *   Copyright (c) 2001-2007 Anton Altaparmakov
 *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
 *
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 *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
 *    Copyright (C) 2015 Andrew Lutomirski
 *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
 *
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 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

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#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/init.h>
#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/uuid.h>
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#include <linux/wmi.h>
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#include <uapi/linux/wmi.h>
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ACPI_MODULE_NAME("wmi");
MODULE_AUTHOR("Carlos Corbacho");
MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
MODULE_LICENSE("GPL");

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static LIST_HEAD(wmi_block_list);
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struct guid_block {
	char guid[16];
	union {
		char object_id[2];
		struct {
			unsigned char notify_id;
			unsigned char reserved;
		};
	};
	u8 instance_count;
	u8 flags;
};

struct wmi_block {
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	struct wmi_device dev;
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	struct list_head list;
	struct guid_block gblock;
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	struct miscdevice char_dev;
	struct mutex char_mutex;
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	struct acpi_device *acpi_device;
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	wmi_notify_handler handler;
	void *handler_data;
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	u64 req_buf_size;
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	bool read_takes_no_args;
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};


/*
 * If the GUID data block is marked as expensive, we must enable and
 * explicitily disable data collection.
 */
#define ACPI_WMI_EXPENSIVE   0x1
#define ACPI_WMI_METHOD      0x2	/* GUID is a method */
#define ACPI_WMI_STRING      0x4	/* GUID takes & returns a string */
#define ACPI_WMI_EVENT       0x8	/* GUID is an event */

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static bool debug_event;
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module_param(debug_event, bool, 0444);
MODULE_PARM_DESC(debug_event,
		 "Log WMI Events [0/1]");

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static bool debug_dump_wdg;
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module_param(debug_dump_wdg, bool, 0444);
MODULE_PARM_DESC(debug_dump_wdg,
		 "Dump available WMI interfaces [0/1]");

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static int acpi_wmi_remove(struct platform_device *device);
static int acpi_wmi_probe(struct platform_device *device);
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static const struct acpi_device_id wmi_device_ids[] = {
	{"PNP0C14", 0},
	{"pnp0c14", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, wmi_device_ids);

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static struct platform_driver acpi_wmi_driver = {
	.driver = {
		.name = "acpi-wmi",
		.acpi_match_table = wmi_device_ids,
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	},
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	.probe = acpi_wmi_probe,
	.remove = acpi_wmi_remove,
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};

/*
 * GUID parsing functions
 */

static bool find_guid(const char *guid_string, struct wmi_block **out)
{
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	uuid_le guid_input;
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	struct wmi_block *wblock;
	struct guid_block *block;
	struct list_head *p;

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	if (uuid_le_to_bin(guid_string, &guid_input))
		return false;
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	list_for_each(p, &wmi_block_list) {
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		wblock = list_entry(p, struct wmi_block, list);
		block = &wblock->gblock;

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		if (memcmp(block->guid, &guid_input, 16) == 0) {
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			if (out)
				*out = wblock;
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			return true;
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		}
	}
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	return false;
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}

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static int get_subobj_info(acpi_handle handle, const char *pathname,
			   struct acpi_device_info **info)
{
	struct acpi_device_info *dummy_info, **info_ptr;
	acpi_handle subobj_handle;
	acpi_status status;

	status = acpi_get_handle(handle, (char *)pathname, &subobj_handle);
	if (status == AE_NOT_FOUND)
		return -ENOENT;
	else if (ACPI_FAILURE(status))
		return -EIO;

	info_ptr = info ? info : &dummy_info;
	status = acpi_get_object_info(subobj_handle, info_ptr);
	if (ACPI_FAILURE(status))
		return -EIO;

	if (!info)
		kfree(dummy_info);

	return 0;
}

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static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
{
	struct guid_block *block = NULL;
	char method[5];
	acpi_status status;
	acpi_handle handle;

	block = &wblock->gblock;
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	handle = wblock->acpi_device->handle;
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	snprintf(method, 5, "WE%02X", block->notify_id);
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	status = acpi_execute_simple_method(handle, method, enable);
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	if (status != AE_OK && status != AE_NOT_FOUND)
		return status;
	else
		return AE_OK;
}

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/*
 * Exported WMI functions
 */
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/**
 * set_required_buffer_size - Sets the buffer size needed for performing IOCTL
 * @wdev: A wmi bus device from a driver
 * @instance: Instance index
 *
 * Allocates memory needed for buffer, stores the buffer size in that memory
 */
int set_required_buffer_size(struct wmi_device *wdev, u64 length)
{
	struct wmi_block *wblock;

	wblock = container_of(wdev, struct wmi_block, dev);
	wblock->req_buf_size = length;

	return 0;
}
EXPORT_SYMBOL_GPL(set_required_buffer_size);

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/**
 * wmi_evaluate_method - Evaluate a WMI method
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * @method_id: Method ID to call
 * &in: Buffer containing input for the method call
 * &out: Empty buffer to return the method results
 *
 * Call an ACPI-WMI method
 */
acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
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{
	struct wmi_block *wblock = NULL;

	if (!find_guid(guid_string, &wblock))
		return AE_ERROR;
	return wmidev_evaluate_method(&wblock->dev, instance, method_id,
				      in, out);
}
EXPORT_SYMBOL_GPL(wmi_evaluate_method);

/**
 * wmidev_evaluate_method - Evaluate a WMI method
 * @wdev: A wmi bus device from a driver
 * @instance: Instance index
 * @method_id: Method ID to call
 * &in: Buffer containing input for the method call
 * &out: Empty buffer to return the method results
 *
 * Call an ACPI-WMI method
 */
acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance,
	u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
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{
	struct guid_block *block = NULL;
	struct wmi_block *wblock = NULL;
	acpi_handle handle;
	acpi_status status;
	struct acpi_object_list input;
	union acpi_object params[3];
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	char method[5] = "WM";
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	wblock = container_of(wdev, struct wmi_block, dev);
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	block = &wblock->gblock;
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	handle = wblock->acpi_device->handle;
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	if (!(block->flags & ACPI_WMI_METHOD))
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		return AE_BAD_DATA;

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	if (block->instance_count <= instance)
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		return AE_BAD_PARAMETER;

	input.count = 2;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = instance;
	params[1].type = ACPI_TYPE_INTEGER;
	params[1].integer.value = method_id;

	if (in) {
		input.count = 3;

		if (block->flags & ACPI_WMI_STRING) {
			params[2].type = ACPI_TYPE_STRING;
		} else {
			params[2].type = ACPI_TYPE_BUFFER;
		}
		params[2].buffer.length = in->length;
		params[2].buffer.pointer = in->pointer;
	}

	strncat(method, block->object_id, 2);

	status = acpi_evaluate_object(handle, method, &input, out);

	return status;
}
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EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
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static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
				 struct acpi_buffer *out)
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{
	struct guid_block *block = NULL;
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	acpi_handle handle;
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	acpi_status status, wc_status = AE_ERROR;
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	struct acpi_object_list input;
	union acpi_object wq_params[1];
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	char method[5];
	char wc_method[5] = "WC";
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	if (!out)
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		return AE_BAD_PARAMETER;

	block = &wblock->gblock;
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	handle = wblock->acpi_device->handle;
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	if (block->instance_count <= instance)
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		return AE_BAD_PARAMETER;

	/* Check GUID is a data block */
	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
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		return AE_ERROR;
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	input.count = 1;
	input.pointer = wq_params;
	wq_params[0].type = ACPI_TYPE_INTEGER;
	wq_params[0].integer.value = instance;

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	if (instance == 0 && wblock->read_takes_no_args)
		input.count = 0;

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	/*
	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
	 * enable collection.
	 */
	if (block->flags & ACPI_WMI_EXPENSIVE) {
		strncat(wc_method, block->object_id, 2);

		/*
		 * Some GUIDs break the specification by declaring themselves
		 * expensive, but have no corresponding WCxx method. So we
		 * should not fail if this happens.
		 */
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		if (acpi_has_method(handle, wc_method))
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			wc_status = acpi_execute_simple_method(handle,
								wc_method, 1);
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	}

	strcpy(method, "WQ");
	strncat(method, block->object_id, 2);

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	status = acpi_evaluate_object(handle, method, &input, out);
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	/*
	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
	 * the WQxx method failed - we should disable collection anyway.
	 */
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	if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
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		status = acpi_execute_simple_method(handle, wc_method, 0);
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	}

	return status;
}
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/**
 * wmi_query_block - Return contents of a WMI block (deprecated)
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * &out: Empty buffer to return the contents of the data block to
 *
 * Return the contents of an ACPI-WMI data block to a buffer
 */
acpi_status wmi_query_block(const char *guid_string, u8 instance,
			    struct acpi_buffer *out)
{
	struct wmi_block *wblock;

	if (!guid_string)
		return AE_BAD_PARAMETER;

	if (!find_guid(guid_string, &wblock))
		return AE_ERROR;

	return __query_block(wblock, instance, out);
}
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EXPORT_SYMBOL_GPL(wmi_query_block);

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union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
{
	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);

	if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
		return NULL;

	return (union acpi_object *)out.pointer;
}
EXPORT_SYMBOL_GPL(wmidev_block_query);

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/**
 * wmi_set_block - Write to a WMI block
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @instance: Instance index
 * &in: Buffer containing new values for the data block
 *
 * Write the contents of the input buffer to an ACPI-WMI data block
 */
acpi_status wmi_set_block(const char *guid_string, u8 instance,
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			  const struct acpi_buffer *in)
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{
	struct guid_block *block = NULL;
	struct wmi_block *wblock = NULL;
	acpi_handle handle;
	struct acpi_object_list input;
	union acpi_object params[2];
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	char method[5] = "WS";
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	if (!guid_string || !in)
		return AE_BAD_DATA;

	if (!find_guid(guid_string, &wblock))
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		return AE_ERROR;
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	block = &wblock->gblock;
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	handle = wblock->acpi_device->handle;
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	if (block->instance_count <= instance)
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		return AE_BAD_PARAMETER;

	/* Check GUID is a data block */
	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
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		return AE_ERROR;
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	input.count = 2;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = instance;

	if (block->flags & ACPI_WMI_STRING) {
		params[1].type = ACPI_TYPE_STRING;
	} else {
		params[1].type = ACPI_TYPE_BUFFER;
	}
	params[1].buffer.length = in->length;
	params[1].buffer.pointer = in->pointer;

	strncat(method, block->object_id, 2);

	return acpi_evaluate_object(handle, method, &input, NULL);
}
EXPORT_SYMBOL_GPL(wmi_set_block);

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static void wmi_dump_wdg(const struct guid_block *g)
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{
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	pr_info("%pUL:\n", g->guid);
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	if (g->flags & ACPI_WMI_EVENT)
		pr_info("\tnotify_id: 0x%02X\n", g->notify_id);
	else
		pr_info("\tobject_id: %2pE\n", g->object_id);
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	pr_info("\tinstance_count: %d\n", g->instance_count);
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	pr_info("\tflags: %#x", g->flags);
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	if (g->flags) {
		if (g->flags & ACPI_WMI_EXPENSIVE)
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			pr_cont(" ACPI_WMI_EXPENSIVE");
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		if (g->flags & ACPI_WMI_METHOD)
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			pr_cont(" ACPI_WMI_METHOD");
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		if (g->flags & ACPI_WMI_STRING)
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			pr_cont(" ACPI_WMI_STRING");
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		if (g->flags & ACPI_WMI_EVENT)
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			pr_cont(" ACPI_WMI_EVENT");
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	}
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	pr_cont("\n");
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}

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static void wmi_notify_debug(u32 value, void *context)
{
	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *obj;
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	acpi_status status;
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	status = wmi_get_event_data(value, &response);
	if (status != AE_OK) {
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		pr_info("bad event status 0x%x\n", status);
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		return;
	}
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	obj = (union acpi_object *)response.pointer;

	if (!obj)
		return;

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	pr_info("DEBUG Event ");
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	switch(obj->type) {
	case ACPI_TYPE_BUFFER:
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		pr_cont("BUFFER_TYPE - length %d\n", obj->buffer.length);
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		break;
	case ACPI_TYPE_STRING:
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		pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
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		break;
	case ACPI_TYPE_INTEGER:
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		pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
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		break;
	case ACPI_TYPE_PACKAGE:
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		pr_cont("PACKAGE_TYPE - %d elements\n", obj->package.count);
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		break;
	default:
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		pr_cont("object type 0x%X\n", obj->type);
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	}
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	kfree(obj);
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}

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/**
 * wmi_install_notify_handler - Register handler for WMI events
 * @handler: Function to handle notifications
 * @data: Data to be returned to handler when event is fired
 *
 * Register a handler for events sent to the ACPI-WMI mapper device.
 */
acpi_status wmi_install_notify_handler(const char *guid,
wmi_notify_handler handler, void *data)
{
	struct wmi_block *block;
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	acpi_status status = AE_NOT_EXIST;
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	uuid_le guid_input;
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	struct list_head *p;
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	if (!guid || !handler)
		return AE_BAD_PARAMETER;

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	if (uuid_le_to_bin(guid, &guid_input))
		return AE_BAD_PARAMETER;
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	list_for_each(p, &wmi_block_list) {
		acpi_status wmi_status;
		block = list_entry(p, struct wmi_block, list);

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		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
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			if (block->handler &&
			    block->handler != wmi_notify_debug)
				return AE_ALREADY_ACQUIRED;
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			block->handler = handler;
			block->handler_data = data;
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			wmi_status = wmi_method_enable(block, 1);
			if ((wmi_status != AE_OK) ||
			    ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
				status = wmi_status;
		}
	}
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	return status;
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}
EXPORT_SYMBOL_GPL(wmi_install_notify_handler);

/**
 * wmi_uninstall_notify_handler - Unregister handler for WMI events
 *
 * Unregister handler for events sent to the ACPI-WMI mapper device.
 */
acpi_status wmi_remove_notify_handler(const char *guid)
{
	struct wmi_block *block;
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	acpi_status status = AE_NOT_EXIST;
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	uuid_le guid_input;
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	struct list_head *p;
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	if (!guid)
		return AE_BAD_PARAMETER;

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	if (uuid_le_to_bin(guid, &guid_input))
		return AE_BAD_PARAMETER;
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	list_for_each(p, &wmi_block_list) {
		acpi_status wmi_status;
		block = list_entry(p, struct wmi_block, list);

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		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
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			if (!block->handler ||
			    block->handler == wmi_notify_debug)
				return AE_NULL_ENTRY;

			if (debug_event) {
				block->handler = wmi_notify_debug;
				status = AE_OK;
			} else {
				wmi_status = wmi_method_enable(block, 0);
				block->handler = NULL;
				block->handler_data = NULL;
				if ((wmi_status != AE_OK) ||
				    ((wmi_status == AE_OK) &&
				     (status == AE_NOT_EXIST)))
					status = wmi_status;
			}
		}
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	}
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	return status;
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}
EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);

/**
 * wmi_get_event_data - Get WMI data associated with an event
 *
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 * @event: Event to find
 * @out: Buffer to hold event data. out->pointer should be freed with kfree()
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616
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618
619
 *
 * Returns extra data associated with an event in WMI.
 */
acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
{
	struct acpi_object_list input;
	union acpi_object params[1];
	struct guid_block *gblock;
	struct wmi_block *wblock;
	struct list_head *p;

	input.count = 1;
	input.pointer = params;
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = event;

620
	list_for_each(p, &wmi_block_list) {
621
622
623
624
625
		wblock = list_entry(p, struct wmi_block, list);
		gblock = &wblock->gblock;

		if ((gblock->flags & ACPI_WMI_EVENT) &&
			(gblock->notify_id == event))
626
627
			return acpi_evaluate_object(wblock->acpi_device->handle,
				"_WED", &input, out);
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
	}

	return AE_NOT_FOUND;
}
EXPORT_SYMBOL_GPL(wmi_get_event_data);

/**
 * wmi_has_guid - Check if a GUID is available
 * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 *
 * Check if a given GUID is defined by _WDG
 */
bool wmi_has_guid(const char *guid_string)
{
	return find_guid(guid_string, NULL);
}
EXPORT_SYMBOL_GPL(wmi_has_guid);

646
647
648
649
650
651
652
653
654
655
static struct wmi_block *dev_to_wblock(struct device *dev)
{
	return container_of(dev, struct wmi_block, dev.dev);
}

static struct wmi_device *dev_to_wdev(struct device *dev)
{
	return container_of(dev, struct wmi_device, dev);
}

656
657
658
/*
 * sysfs interface
 */
659
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
660
661
			     char *buf)
{
662
	struct wmi_block *wblock = dev_to_wblock(dev);
663

664
	return sprintf(buf, "wmi:%pUL\n", wblock->gblock.guid);
665
}
666
static DEVICE_ATTR_RO(modalias);
667

668
669
670
671
672
673
674
675
676
static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%pUL\n", wblock->gblock.guid);
}
static DEVICE_ATTR_RO(guid);

677
678
679
680
681
682
683
684
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686
687
688
689
690
691
692
693
694
695
static ssize_t instance_count_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%d\n", (int)wblock->gblock.instance_count);
}
static DEVICE_ATTR_RO(instance_count);

static ssize_t expensive_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%d\n",
		       (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
}
static DEVICE_ATTR_RO(expensive);

696
697
static struct attribute *wmi_attrs[] = {
	&dev_attr_modalias.attr,
698
	&dev_attr_guid.attr,
699
700
	&dev_attr_instance_count.attr,
	&dev_attr_expensive.attr,
701
	NULL,
702
};
703
ATTRIBUTE_GROUPS(wmi);
704

705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
}
static DEVICE_ATTR_RO(notify_id);

static struct attribute *wmi_event_attrs[] = {
	&dev_attr_notify_id.attr,
	NULL,
};
ATTRIBUTE_GROUPS(wmi_event);

static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	return sprintf(buf, "%c%c\n", wblock->gblock.object_id[0],
		       wblock->gblock.object_id[1]);
}
static DEVICE_ATTR_RO(object_id);

730
731
static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
732
733
734
{
	struct wmi_device *wdev = dev_to_wdev(dev);

735
	return sprintf(buf, "%d\n", (int)wdev->setable);
736
}
737
static DEVICE_ATTR_RO(setable);
738
739
740

static struct attribute *wmi_data_attrs[] = {
	&dev_attr_object_id.attr,
741
	&dev_attr_setable.attr,
742
743
744
745
746
	NULL,
};
ATTRIBUTE_GROUPS(wmi_data);

static struct attribute *wmi_method_attrs[] = {
747
748
749
	&dev_attr_object_id.attr,
	NULL,
};
750
ATTRIBUTE_GROUPS(wmi_method);
751

752
753
static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
{
754
	struct wmi_block *wblock = dev_to_wblock(dev);
755

756
	if (add_uevent_var(env, "MODALIAS=wmi:%pUL", wblock->gblock.guid))
757
758
		return -ENOMEM;

759
	if (add_uevent_var(env, "WMI_GUID=%pUL", wblock->gblock.guid))
760
761
		return -ENOMEM;

762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
	return 0;
}

static void wmi_dev_release(struct device *dev)
{
	struct wmi_block *wblock = dev_to_wblock(dev);

	kfree(wblock);
}

static int wmi_dev_match(struct device *dev, struct device_driver *driver)
{
	struct wmi_driver *wmi_driver =
		container_of(driver, struct wmi_driver, driver);
	struct wmi_block *wblock = dev_to_wblock(dev);
	const struct wmi_device_id *id = wmi_driver->id_table;
778

779
780
781
782
783
784
785
786
787
788
	while (id->guid_string) {
		uuid_le driver_guid;

		if (WARN_ON(uuid_le_to_bin(id->guid_string, &driver_guid)))
			continue;
		if (!memcmp(&driver_guid, wblock->gblock.guid, 16))
			return 1;

		id++;
	}
789
790
791

	return 0;
}
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
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813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
static int wmi_char_open(struct inode *inode, struct file *filp)
{
	const char *driver_name = filp->f_path.dentry->d_iname;
	struct wmi_block *wblock = NULL;
	struct wmi_block *next = NULL;

	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
		if (!wblock->dev.dev.driver)
			continue;
		if (strcmp(driver_name, wblock->dev.dev.driver->name) == 0) {
			filp->private_data = wblock;
			break;
		}
	}

	if (!filp->private_data)
		return -ENODEV;

	return nonseekable_open(inode, filp);
}

static ssize_t wmi_char_read(struct file *filp, char __user *buffer,
	size_t length, loff_t *offset)
{
	struct wmi_block *wblock = filp->private_data;

	return simple_read_from_buffer(buffer, length, offset,
				       &wblock->req_buf_size,
				       sizeof(wblock->req_buf_size));
}

static long wmi_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct wmi_ioctl_buffer __user *input =
		(struct wmi_ioctl_buffer __user *) arg;
	struct wmi_block *wblock = filp->private_data;
	struct wmi_ioctl_buffer *buf = NULL;
	struct wmi_driver *wdriver = NULL;
	int ret;

	if (_IOC_TYPE(cmd) != WMI_IOC)
		return -ENOTTY;

	/* make sure we're not calling a higher instance than exists*/
	if (_IOC_NR(cmd) >= wblock->gblock.instance_count)
		return -EINVAL;

	mutex_lock(&wblock->char_mutex);
	buf = wblock->handler_data;
	if (get_user(buf->length, &input->length)) {
		dev_dbg(&wblock->dev.dev, "Read length from user failed\n");
		ret = -EFAULT;
		goto out_ioctl;
	}
	/* if it's too small, abort */
	if (buf->length < wblock->req_buf_size) {
		dev_err(&wblock->dev.dev,
			"Buffer %lld too small, need at least %lld\n",
			buf->length, wblock->req_buf_size);
		ret = -EINVAL;
		goto out_ioctl;
	}
	/* if it's too big, warn, driver will only use what is needed */
	if (buf->length > wblock->req_buf_size)
		dev_warn(&wblock->dev.dev,
			"Buffer %lld is bigger than required %lld\n",
			buf->length, wblock->req_buf_size);

	/* copy the structure from userspace */
	if (copy_from_user(buf, input, wblock->req_buf_size)) {
		dev_dbg(&wblock->dev.dev, "Copy %llu from user failed\n",
			wblock->req_buf_size);
		ret = -EFAULT;
		goto out_ioctl;
	}

	/* let the driver do any filtering and do the call */
	wdriver = container_of(wblock->dev.dev.driver,
			       struct wmi_driver, driver);
871
872
873
874
	if (!try_module_get(wdriver->driver.owner)) {
		ret = -EBUSY;
		goto out_ioctl;
	}
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
	ret = wdriver->filter_callback(&wblock->dev, cmd, buf);
	module_put(wdriver->driver.owner);
	if (ret)
		goto out_ioctl;

	/* return the result (only up to our internal buffer size) */
	if (copy_to_user(input, buf, wblock->req_buf_size)) {
		dev_dbg(&wblock->dev.dev, "Copy %llu to user failed\n",
			wblock->req_buf_size);
		ret = -EFAULT;
	}

out_ioctl:
	mutex_unlock(&wblock->char_mutex);
	return ret;
}

static const struct file_operations wmi_fops = {
	.owner		= THIS_MODULE,
	.read		= wmi_char_read,
	.open		= wmi_char_open,
	.unlocked_ioctl	= wmi_ioctl,
	.compat_ioctl	= wmi_ioctl,
};
899

900
static int wmi_dev_probe(struct device *dev)
901
{
902
903
904
905
	struct wmi_block *wblock = dev_to_wblock(dev);
	struct wmi_driver *wdriver =
		container_of(dev->driver, struct wmi_driver, driver);
	int ret = 0;
906
907
	int count;
	char *buf;
908
909
910
911
912
913

	if (ACPI_FAILURE(wmi_method_enable(wblock, 1)))
		dev_warn(dev, "failed to enable device -- probing anyway\n");

	if (wdriver->probe) {
		ret = wdriver->probe(dev_to_wdev(dev));
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
		if (ret != 0)
			goto probe_failure;
	}

	/* driver wants a character device made */
	if (wdriver->filter_callback) {
		/* check that required buffer size declared by driver or MOF */
		if (!wblock->req_buf_size) {
			dev_err(&wblock->dev.dev,
				"Required buffer size not set\n");
			ret = -EINVAL;
			goto probe_failure;
		}

		count = get_order(wblock->req_buf_size);
		wblock->handler_data = (void *)__get_free_pages(GFP_KERNEL,
								count);
		if (!wblock->handler_data) {
			ret = -ENOMEM;
			goto probe_failure;
		}

		buf = kmalloc(strlen(wdriver->driver.name) + 4, GFP_KERNEL);
		if (!buf) {
			ret = -ENOMEM;
			goto probe_string_failure;
		}
		sprintf(buf, "wmi/%s", wdriver->driver.name);
		wblock->char_dev.minor = MISC_DYNAMIC_MINOR;
		wblock->char_dev.name = buf;
		wblock->char_dev.fops = &wmi_fops;
		wblock->char_dev.mode = 0444;
		ret = misc_register(&wblock->char_dev);
		if (ret) {
			dev_warn(dev, "failed to register char dev: %d", ret);
			ret = -ENOMEM;
			goto probe_misc_failure;
		}
952
953
	}

954
955
956
957
958
959
960
961
962
	return 0;

probe_misc_failure:
	kfree(buf);
probe_string_failure:
	kfree(wblock->handler_data);
probe_failure:
	if (ACPI_FAILURE(wmi_method_enable(wblock, 0)))
		dev_warn(dev, "failed to disable device\n");
963
964
965
966
967
968
969
970
971
972
	return ret;
}

static int wmi_dev_remove(struct device *dev)
{
	struct wmi_block *wblock = dev_to_wblock(dev);
	struct wmi_driver *wdriver =
		container_of(dev->driver, struct wmi_driver, driver);
	int ret = 0;

973
974
975
976
977
978
979
	if (wdriver->filter_callback) {
		misc_deregister(&wblock->char_dev);
		kfree(wblock->char_dev.name);
		free_pages((unsigned long)wblock->handler_data,
			   get_order(wblock->req_buf_size));
	}

980
981
982
983
984
	if (wdriver->remove)
		ret = wdriver->remove(dev_to_wdev(dev));

	if (ACPI_FAILURE(wmi_method_enable(wblock, 0)))
		dev_warn(dev, "failed to disable device\n");
985

986
	return ret;
987
988
}

989
990
991
992
993
static struct class wmi_bus_class = {
	.name = "wmi_bus",
};

static struct bus_type wmi_bus_type = {
994
	.name = "wmi",
995
	.dev_groups = wmi_groups,
996
997
998
999
	.match = wmi_dev_match,
	.uevent = wmi_dev_uevent,
	.probe = wmi_dev_probe,
	.remove = wmi_dev_remove,
1000
};
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