Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1458 insertions, 0 deletions

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
new file mode 100644
index 000000000..387358af6
--- /dev/null
+++ b/drivers/platform/x86/wmi.c
@@ -0,0 +1,1458 @@
+/*
+ *  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)) {
+		/*
+		 * Ignore whether this WCxx call succeeds or not since
+		 * the previously executed WQxx method call might have
+		 * succeeded, and returning the failing status code
+		 * of this call would throw away the result of the WQxx
+		 * call, potentially leaking memory.
+		 */
+		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);