text: /*
   *  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>
   *
   *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
   *    Copyright (C) 2015 Andrew Lutomirski
   *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  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.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   */
  
  #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
  
  #include <linux/acpi.h>
  #include <linux/device.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/list.h>
  #include <linux/miscdevice.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/types.h>
  #include <linux/uaccess.h>
  #include <linux/uuid.h>
  #include <linux/wmi.h>
  #include <uapi/linux/wmi.h>
  
  ACPI_MODULE_NAME("wmi");
  MODULE_AUTHOR("Carlos Corbacho");
  MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  MODULE_LICENSE("GPL");
  
  static LIST_HEAD(wmi_block_list);
  
  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 {
  	struct wmi_device dev;
  	struct list_head list;
  	struct guid_block gblock;
  	struct miscdevice char_dev;
  	struct mutex char_mutex;
  	struct acpi_device *acpi_device;
  	wmi_notify_handler handler;
  	void *handler_data;
  	u64 req_buf_size;
  
  	bool read_takes_no_args;
  };
  
  
  /*
   * 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 */
  
  static bool debug_event;
  module_param(debug_event, bool, 0444);
  MODULE_PARM_DESC(debug_event,
  		 "Log WMI Events [0/1]");
  
  static bool debug_dump_wdg;
  module_param(debug_dump_wdg, bool, 0444);
  MODULE_PARM_DESC(debug_dump_wdg,
  		 "Dump available WMI interfaces [0/1]");
  
  static int acpi_wmi_remove(struct platform_device *device);
  static int acpi_wmi_probe(struct platform_device *device);
  
  static const struct acpi_device_id wmi_device_ids[] = {
  	{"PNP0C14", 0},
  	{"pnp0c14", 0},
  	{"", 0},
  };
  MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
  
  static struct platform_driver acpi_wmi_driver = {
  	.driver = {
  		.name = "acpi-wmi",
  		.acpi_match_table = wmi_device_ids,
  	},
  	.probe = acpi_wmi_probe,
  	.remove = acpi_wmi_remove,
  };
  
  /*
   * GUID parsing functions
   */
  
  static bool find_guid(const char *guid_string, struct wmi_block **out)
  {
  	uuid_le guid_input;
  	struct wmi_block *wblock;
  	struct guid_block *block;
  
  	if (uuid_le_to_bin(guid_string, &guid_input))
  		return false;
  
  	list_for_each_entry(wblock, &wmi_block_list, list) {
  		block = &wblock->gblock;
  
  		if (memcmp(block->guid, &guid_input, 16) == 0) {
  			if (out)
  				*out = wblock;
  			return true;
  		}
  	}
  	return false;
  }
  
  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;
  }
  
  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;
  	handle = wblock->acpi_device->handle;
  
  	snprintf(method, 5, "WE%02X", block->notify_id);
  	status = acpi_execute_simple_method(handle, method, enable);
  
  	if (status != AE_OK && status != AE_NOT_FOUND)
  		return status;
  	else
  		return AE_OK;
  }
  
  /*
   * Exported WMI functions
   */
  
  /**
   * 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);
  
  /**
   * 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)
  {
  	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)
  {
  	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];
  	char method[5] = "WM";
  
  	wblock = container_of(wdev, struct wmi_block, dev);
  	block = &wblock->gblock;
  	handle = wblock->acpi_device->handle;
  
  	if (!(block->flags & ACPI_WMI_METHOD))
  		return AE_BAD_DATA;
  
  	if (block->instance_count <= instance)
  		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;
  }
  EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
  
  static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
  				 struct acpi_buffer *out)
  {
  	struct guid_block *block = NULL;
  	acpi_handle handle;
  	acpi_status status, wc_status = AE_ERROR;
  	struct acpi_object_list input;
  	union acpi_object wq_params[1];
  	char method[5];
  	char wc_method[5] = "WC";
  
  	if (!out)
  		return AE_BAD_PARAMETER;
  
  	block = &wblock->gblock;
  	handle = wblock->acpi_device->handle;
  
  	if (block->instance_count <= instance)
  		return AE_BAD_PARAMETER;
  
  	/* Check GUID is a data block */
  	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
  		return AE_ERROR;
  
  	input.count = 1;
  	input.pointer = wq_params;
  	wq_params[0].type = ACPI_TYPE_INTEGER;
  	wq_params[0].integer.value = instance;
  
  	if (instance == 0 && wblock->read_takes_no_args)
  		input.count = 0;
  
  	/*
  	 * 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.
  		 */
  		if (acpi_has_method(handle, wc_method))
  			wc_status = acpi_execute_simple_method(handle,
  								wc_method, 1);
  	}
  
  	strcpy(method, "WQ");
  	strncat(method, block->object_id, 2);
  
  	status = acpi_evaluate_object(handle, method, &input, out);
  
  	/*
  	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
  	 * the WQxx method failed - we should disable collection anyway.
  	 */
  	if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
  		status = acpi_execute_simple_method(handle, wc_method, 0);
  	}
  
  	return status;
  }
  
  /**
   * 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);
  }
  EXPORT_SYMBOL_GPL(wmi_query_block);
  
  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);
  
  /**
   * 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,
  			  const struct acpi_buffer *in)
  {
  	struct guid_block *block = NULL;
  	struct wmi_block *wblock = NULL;
  	acpi_handle handle;
  	struct acpi_object_list input;
  	union acpi_object params[2];
  	char method[5] = "WS";
  
  	if (!guid_string || !in)
  		return AE_BAD_DATA;
  
  	if (!find_guid(guid_string, &wblock))
  		return AE_ERROR;
  
  	block = &wblock->gblock;
  	handle = wblock->acpi_device->handle;
  
  	if (block->instance_count <= instance)
  		return AE_BAD_PARAMETER;
  
  	/* Check GUID is a data block */
  	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
  		return AE_ERROR;
  
  	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);
  
  static void wmi_dump_wdg(const struct guid_block *g)
  {
  	pr_info("%pUL:\n", g->guid);
  	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);
  	pr_info("\tinstance_count: %d\n", g->instance_count);
  	pr_info("\tflags: %#x", g->flags);
  	if (g->flags) {
  		if (g->flags & ACPI_WMI_EXPENSIVE)
  			pr_cont(" ACPI_WMI_EXPENSIVE");
  		if (g->flags & ACPI_WMI_METHOD)
  			pr_cont(" ACPI_WMI_METHOD");
  		if (g->flags & ACPI_WMI_STRING)
  			pr_cont(" ACPI_WMI_STRING");
  		if (g->flags & ACPI_WMI_EVENT)
  			pr_cont(" ACPI_WMI_EVENT");
  	}
  	pr_cont("\n");
  
  }
  
  static void wmi_notify_debug(u32 value, void *context)
  {
  	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
  	union acpi_object *obj;
  	acpi_status status;
  
  	status = wmi_get_event_data(value, &response);
  	if (status != AE_OK) {
  		pr_info("bad event status 0x%x\n", status);
  		return;
  	}
  
  	obj = (union acpi_object *)response.pointer;
  
  	if (!obj)
  		return;
  
  	pr_info("DEBUG Event ");
  	switch(obj->type) {
  	case ACPI_TYPE_BUFFER:
  		pr_cont("BUFFER_TYPE - length %d\n", obj->buffer.length);
  		break;
  	case ACPI_TYPE_STRING:
  		pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
  		break;
  	case ACPI_TYPE_INTEGER:
  		pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
  		break;
  	case ACPI_TYPE_PACKAGE:
  		pr_cont("PACKAGE_TYPE - %d elements\n", obj->package.count);
  		break;
  	default:
  		pr_cont("object type 0x%X\n", obj->type);
  	}
  	kfree(obj);
  }
  
  /**
   * 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;
  	acpi_status status = AE_NOT_EXIST;
  	uuid_le guid_input;
  
  	if (!guid || !handler)
  		return AE_BAD_PARAMETER;
  
  	if (uuid_le_to_bin(guid, &guid_input))
  		return AE_BAD_PARAMETER;
  
  	list_for_each_entry(block, &wmi_block_list, list) {
  		acpi_status wmi_status;
  
  		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
  			if (block->handler &&
  			    block->handler != wmi_notify_debug)
  				return AE_ALREADY_ACQUIRED;
  
  			block->handler = handler;
  			block->handler_data = data;
  
  			wmi_status = wmi_method_enable(block, 1);
  			if ((wmi_status != AE_OK) ||
  			    ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
  				status = wmi_status;
  		}
  	}
  
  	return status;
  }
  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;
  	acpi_status status = AE_NOT_EXIST;
  	uuid_le guid_input;
  
  	if (!guid)
  		return AE_BAD_PARAMETER;
  
  	if (uuid_le_to_bin(guid, &guid_input))
  		return AE_BAD_PARAMETER;
  
  	list_for_each_entry(block, &wmi_block_list, list) {
  		acpi_status wmi_status;
  
  		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
  			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;
  			}
  		}
  	}
  
  	return status;
  }
  EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
  
  /**
   * wmi_get_event_data - Get WMI data associated with an event
   *
   * @event: Event to find
   * @out: Buffer to hold event data. out->pointer should be freed with kfree()
   *
   * 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;
  
  	input.count = 1;
  	input.pointer = params;
  	params[0].type = ACPI_TYPE_INTEGER;
  	params[0].integer.value = event;
  
  	list_for_each_entry(wblock, &wmi_block_list, list) {
  		gblock = &wblock->gblock;
  
  		if ((gblock->flags & ACPI_WMI_EVENT) &&
  			(gblock->notify_id == event))
  			return acpi_evaluate_object(wblock->acpi_device->handle,
  				"_WED", &input, out);
  	}
  
  	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);
  
  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);
  }
  
  /*
   * sysfs interface
   */
  static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
  			     char *buf)
  {
  	struct wmi_block *wblock = dev_to_wblock(dev);
  
  	return sprintf(buf, "wmi:%pUL\n", wblock->gblock.guid);
  }
  static DEVICE_ATTR_RO(modalias);
  
  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);
  
  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);
  
  static struct attribute *wmi_attrs[] = {
  	&dev_attr_modalias.attr,
  	&dev_attr_guid.attr,
  	&dev_attr_instance_count.attr,
  	&dev_attr_expensive.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(wmi);
  
  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);
  
  static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
  			    char *buf)
  {
  	struct wmi_device *wdev = dev_to_wdev(dev);
  
  	return sprintf(buf, "%d\n", (int)wdev->setable);
  }
  static DEVICE_ATTR_RO(setable);
  
  static struct attribute *wmi_data_attrs[] = {
  	&dev_attr_object_id.attr,
  	&dev_attr_setable.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(wmi_data);
  
  static struct attribute *wmi_method_attrs[] = {
  	&dev_attr_object_id.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(wmi_method);
  
  static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct wmi_block *wblock = dev_to_wblock(dev);
  
  	if (add_uevent_var(env, "MODALIAS=wmi:%pUL", wblock->gblock.guid))
  		return -ENOMEM;
  
  	if (add_uevent_var(env, "WMI_GUID=%pUL", wblock->gblock.guid))
  		return -ENOMEM;
  
  	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;
  
  	if (id == NULL)
  		return 0;
  
  	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++;
  	}
  
  	return 0;
  }
  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);
  	if (!try_module_get(wdriver->driver.owner)) {
  		ret = -EBUSY;
  		goto out_ioctl;
  	}
  	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,
  };
  
  static int wmi_dev_probe(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;
  	char *buf;
  
  	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));
  		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;
  		}
  
  		wblock->handler_data = kmalloc(wblock->req_buf_size,
  					       GFP_KERNEL);
  		if (!wblock->handler_data) {
  			ret = -ENOMEM;
  			goto probe_failure;
  		}
  
  		buf = kasprintf(GFP_KERNEL, "wmi/%s", wdriver->driver.name);
  		if (!buf) {
  			ret = -ENOMEM;
  			goto probe_string_failure;
  		}
  		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\n", ret);
  			ret = -ENOMEM;
  			goto probe_misc_failure;
  		}
  	}
  
  	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");
  	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;
  
  	if (wdriver->filter_callback) {
  		misc_deregister(&wblock->char_dev);
  		kfree(wblock->char_dev.name);
  		kfree(wblock->handler_data);
  	}
  
  	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");
  
  	return ret;
  }
  
  static struct class wmi_bus_class = {
  	.name = "wmi_bus",
  };
  
  static struct bus_type wmi_bus_type = {
  	.name = "wmi",
  	.dev_groups = wmi_groups,
  	.match = wmi_dev_match,
  	.uevent = wmi_dev_uevent,
  	.probe = wmi_dev_probe,
  	.remove = wmi_dev_remove,
  };
  
  static struct device_type wmi_type_event = {
  	.name = "event",
  	.groups = wmi_event_groups,
  	.release = wmi_dev_release,
  };
  
  static struct device_type wmi_type_method = {
  	.name = "method",
  	.groups = wmi_method_groups,
  	.release = wmi_dev_release,
  };
  
  static struct device_type wmi_type_data = {
  	.name = "data",
  	.groups = wmi_data_groups,
  	.release = wmi_dev_release,
  };
  
  static int wmi_create_device(struct device *wmi_bus_dev,
  			     const struct guid_block *gblock,
  			     struct wmi_block *wblock,
  			     struct acpi_device *device)
  {
  	struct acpi_device_info *info;
  	char method[5];
  	int result;
  
  	if (gblock->flags & ACPI_WMI_EVENT) {
  		wblock->dev.dev.type = &wmi_type_event;
  		goto out_init;
  	}
  
  	if (gblock->flags & ACPI_WMI_METHOD) {
  		wblock->dev.dev.type = &wmi_type_method;
  		mutex_init(&wblock->char_mutex);
  		goto out_init;
  	}
  
  	/*
  	 * Data Block Query Control Method (WQxx by convention) is
  	 * required per the WMI documentation. If it is not present,
  	 * we ignore this data block.
  	 */
  	strcpy(method, "WQ");
  	strncat(method, wblock->gblock.object_id, 2);
  	result = get_subobj_info(device->handle, method, &info);
  
  	if (result) {
  		dev_warn(wmi_bus_dev,
  			 "%s data block query control method not found\n",
  			 method);
  		return result;
  	}
  
  	wblock->dev.dev.type = &wmi_type_data;
  
  	/*
  	 * The Microsoft documentation specifically states:
  	 *
  	 *   Data blocks registered with only a single instance
  	 *   can ignore the parameter.
  	 *
  	 * ACPICA will get mad at us if we call the method with the wrong number
  	 * of arguments, so check what our method expects.  (On some Dell
  	 * laptops, WQxx may not be a method at all.)
  	 */
  	if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
  		wblock->read_takes_no_args = true;
  
  	kfree(info);
  
  	strcpy(method, "WS");
  	strncat(method, wblock->gblock.object_id, 2);
  	result = get_subobj_info(device->handle, method, NULL);
  
  	if (result == 0)
  		wblock->dev.setable = true;
  
   out_init:
  	wblock->dev.dev.bus = &wmi_bus_type;
  	wblock->dev.dev.parent = wmi_bus_dev;
  
  	dev_set_name(&wblock->dev.dev, "%pUL", gblock->guid);
  
  	device_initialize(&wblock->dev.dev);
  
  	return 0;
  }
  
  static void wmi_free_devices(struct acpi_device *device)
  {
  	struct wmi_block *wblock, *next;
  
  	/* Delete devices for all the GUIDs */
  	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
  		if (wblock->acpi_device == device) {
  			list_del(&wblock->list);
  			device_unregister(&wblock->dev.dev);
  		}
  	}
  }
  
  static bool guid_already_parsed(struct acpi_device *device,
  				const u8 *guid)
  {
  	struct wmi_block *wblock;
  
  	list_for_each_entry(wblock, &wmi_block_list, list) {
  		if (memcmp(wblock->gblock.guid, guid, 16) == 0) {
  			/*
  			 * Because we historically didn't track the relationship
  			 * between GUIDs and ACPI nodes, we don't know whether
  			 * we need to suppress GUIDs that are unique on a
  			 * given node but duplicated across nodes.
  			 */
  			dev_warn(&device->dev, "duplicate WMI GUID %pUL (first instance was on %s)\n",
  				 guid, dev_name(&wblock->acpi_device->dev));
  			return true;
  		}
  	}
  
  	return false;
  }
  
  /*
   * Parse the _WDG method for the GUID data blocks
   */
  static int parse_wdg(struct device *wmi_bus_dev, struct acpi_device *device)
  {
  	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
  	const struct guid_block *gblock;
  	struct wmi_block *wblock, *next;
  	union acpi_object *obj;
  	acpi_status status;
  	int retval = 0;
  	u32 i, total;
  
  	status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
  	if (ACPI_FAILURE(status))
  		return -ENXIO;
  
  	obj = (union acpi_object *) out.pointer;
  	if (!obj)
  		return -ENXIO;
  
  	if (obj->type != ACPI_TYPE_BUFFER) {
  		retval = -ENXIO;
  		goto out_free_pointer;
  	}
  
  	gblock = (const struct guid_block *)obj->buffer.pointer;
  	total = obj->buffer.length / sizeof(struct guid_block);
  
  	for (i = 0; i < total; i++) {
  		if (debug_dump_wdg)
  			wmi_dump_wdg(&gblock[i]);
  
  		/*
  		 * Some WMI devices, like those for nVidia hooks, have a
  		 * duplicate GUID. It's not clear what we should do in this
  		 * case yet, so for now, we'll just ignore the duplicate
  		 * for device creation.
  		 */
  		if (guid_already_parsed(device, gblock[i].guid))
  			continue;
  
  		wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
  		if (!wblock) {
  			retval = -ENOMEM;
  			break;
  		}
  
  		wblock->acpi_device = device;
  		wblock->gblock = gblock[i];
  
  		retval = wmi_create_device(wmi_bus_dev, &gblock[i], wblock, device);
  		if (retval) {
  			kfree(wblock);
  			continue;
  		}
  
  		list_add_tail(&wblock->list, &wmi_block_list);
  
  		if (debug_event) {
  			wblock->handler = wmi_notify_debug;
  			wmi_method_enable(wblock, 1);
  		}
  	}
  
  	/*
  	 * Now that all of the devices are created, add them to the
  	 * device tree and probe subdrivers.
  	 */
  	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
  		if (wblock->acpi_device != device)
  			continue;
  
  		retval = device_add(&wblock->dev.dev);
  		if (retval) {
  			dev_err(wmi_bus_dev, "failed to register %pUL\n",
  				wblock->gblock.guid);
  			if (debug_event)
  				wmi_method_enable(wblock, 0);
  			list_del(&wblock->list);
  			put_device(&wblock->dev.dev);
  		}
  	}
  
  out_free_pointer:
  	kfree(out.pointer);
  	return retval;
  }
  
  /*
   * WMI can have EmbeddedControl access regions. In which case, we just want to
   * hand these off to the EC driver.
   */
  static acpi_status
  acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
  		      u32 bits, u64 *value,
  		      void *handler_context, void *region_context)
  {
  	int result = 0, i = 0;
  	u8 temp = 0;
  
  	if ((address > 0xFF) || !value)
  		return AE_BAD_PARAMETER;
  
  	if (function != ACPI_READ && function != ACPI_WRITE)
  		return AE_BAD_PARAMETER;
  
  	if (bits != 8)
  		return AE_BAD_PARAMETER;
  
  	if (function == ACPI_READ) {
  		result = ec_read(address, &temp);
  		(*value) |= ((u64)temp) << i;
  	} else {
  		temp = 0xff & ((*value) >> i);
  		result = ec_write(address, temp);
  	}
  
  	switch (result) {
  	case -EINVAL:
  		return AE_BAD_PARAMETER;
  		break;
  	case -ENODEV:
  		return AE_NOT_FOUND;
  		break;
  	case -ETIME:
  		return AE_TIME;
  		break;
  	default:
  		return AE_OK;
  	}
  }
  
  static void acpi_wmi_notify_handler(acpi_handle handle, u32 event,
  				    void *context)
  {
  	struct guid_block *block;
  	struct wmi_block *wblock;
  	bool found_it = false;
  
  	list_for_each_entry(wblock, &wmi_block_list, list) {
  		block = &wblock->gblock;
  
  		if (wblock->acpi_device->handle == handle &&
  		    (block->flags & ACPI_WMI_EVENT) &&
  		    (block->notify_id == event))
  		{
  			found_it = true;
  			break;
  		}
  	}
  
  	if (!found_it)
  		return;
  
  	/* If a driver is bound, then notify the driver. */
  	if (wblock->dev.dev.driver) {
  		struct wmi_driver *driver;
  		struct acpi_object_list input;
  		union acpi_object params[1];
  		struct acpi_buffer evdata = { ACPI_ALLOCATE_BUFFER, NULL };
  		acpi_status status;
  
  		driver = container_of(wblock->dev.dev.driver,
  				      struct wmi_driver, driver);
  
  		input.count = 1;
  		input.pointer = params;
  		params[0].type = ACPI_TYPE_INTEGER;
  		params[0].integer.value = event;
  
  		status = acpi_evaluate_object(wblock->acpi_device->handle,
  					      "_WED", &input, &evdata);
  		if (ACPI_FAILURE(status)) {
  			dev_warn(&wblock->dev.dev,
  				 "failed to get event data\n");
  			return;
  		}
  
  		if (driver->notify)
  			driver->notify(&wblock->dev,
  				       (union acpi_object *)evdata.pointer);
  
  		kfree(evdata.pointer);
  	} else if (wblock->handler) {
  		/* Legacy handler */
  		wblock->handler(event, wblock->handler_data);
  	}
  
  	if (debug_event) {
  		pr_info("DEBUG Event GUID: %pUL\n",
  			wblock->gblock.guid);
  	}
  
  	acpi_bus_generate_netlink_event(
  		wblock->acpi_device->pnp.device_class,
  		dev_name(&wblock->dev.dev),
  		event, 0);
  
  }
  
  static int acpi_wmi_remove(struct platform_device *device)
  {
  	struct acpi_device *acpi_device = ACPI_COMPANION(&device->dev);
  
  	acpi_remove_notify_handler(acpi_device->handle, ACPI_DEVICE_NOTIFY,
  				   acpi_wmi_notify_handler);
  	acpi_remove_address_space_handler(acpi_device->handle,
  				ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
  	wmi_free_devices(acpi_device);
  	device_destroy(&wmi_bus_class, MKDEV(0, 0));
  
  	return 0;
  }
  
  static int acpi_wmi_probe(struct platform_device *device)
  {
  	struct acpi_device *acpi_device;
  	struct device *wmi_bus_dev;
  	acpi_status status;
  	int error;
  
  	acpi_device = ACPI_COMPANION(&device->dev);
  	if (!acpi_device) {
  		dev_err(&device->dev, "ACPI companion is missing\n");
  		return -ENODEV;
  	}
  
  	status = acpi_install_address_space_handler(acpi_device->handle,
  						    ACPI_ADR_SPACE_EC,
  						    &acpi_wmi_ec_space_handler,
  						    NULL, NULL);
  	if (ACPI_FAILURE(status)) {
  		dev_err(&device->dev, "Error installing EC region handler\n");
  		return -ENODEV;
  	}
  
  	status = acpi_install_notify_handler(acpi_device->handle,
  					     ACPI_DEVICE_NOTIFY,
  					     acpi_wmi_notify_handler,
  					     NULL);
  	if (ACPI_FAILURE(status)) {
  		dev_err(&device->dev, "Error installing notify handler\n");
  		error = -ENODEV;
  		goto err_remove_ec_handler;
  	}
  
  	wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0),
  				    NULL, "wmi_bus-%s", dev_name(&device->dev));
  	if (IS_ERR(wmi_bus_dev)) {
  		error = PTR_ERR(wmi_bus_dev);
  		goto err_remove_notify_handler;
  	}
  	dev_set_drvdata(&device->dev, wmi_bus_dev);
  
  	error = parse_wdg(wmi_bus_dev, acpi_device);
  	if (error) {
  		pr_err("Failed to parse WDG method\n");
  		goto err_remove_busdev;
  	}
  
  	return 0;
  
  err_remove_busdev:
  	device_destroy(&wmi_bus_class, MKDEV(0, 0));
  
  err_remove_notify_handler:
  	acpi_remove_notify_handler(acpi_device->handle, ACPI_DEVICE_NOTIFY,
  				   acpi_wmi_notify_handler);
  
  err_remove_ec_handler:
  	acpi_remove_address_space_handler(acpi_device->handle,
  					  ACPI_ADR_SPACE_EC,
  					  &acpi_wmi_ec_space_handler);
  
  	return error;
  }
  
  int __must_check __wmi_driver_register(struct wmi_driver *driver,
  				       struct module *owner)
  {
  	driver->driver.owner = owner;
  	driver->driver.bus = &wmi_bus_type;
  
  	return driver_register(&driver->driver);
  }
  EXPORT_SYMBOL(__wmi_driver_register);
  
  void wmi_driver_unregister(struct wmi_driver *driver)
  {
  	driver_unregister(&driver->driver);
  }
  EXPORT_SYMBOL(wmi_driver_unregister);
  
  static int __init acpi_wmi_init(void)
  {
  	int error;
  
  	if (acpi_disabled)
  		return -ENODEV;
  
  	error = class_register(&wmi_bus_class);
  	if (error)
  		return error;
  
  	error = bus_register(&wmi_bus_type);
  	if (error)
  		goto err_unreg_class;
  
  	error = platform_driver_register(&acpi_wmi_driver);
  	if (error) {
  		pr_err("Error loading mapper\n");
  		goto err_unreg_bus;
  	}
  
  	return 0;
  
  err_unreg_bus:
  	bus_unregister(&wmi_bus_type);
  
  err_unreg_class:
  	class_unregister(&wmi_bus_class);
  
  	return error;
  }
  
  static void __exit acpi_wmi_exit(void)
  {
  	platform_driver_unregister(&acpi_wmi_driver);
  	bus_unregister(&wmi_bus_type);
  	class_unregister(&wmi_bus_class);
  }
  
  subsys_initcall_sync(acpi_wmi_init);
  module_exit(acpi_wmi_exit);
  