wmi-bmof.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * WMI embedded Binary MOF driver
  4 *
  5 * Copyright (c) 2015 Andrew Lutomirski
  6 * Copyright (C) 2017 VMware, Inc. All Rights Reserved.
  7 */
  8
  9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 10
 11#include <linux/acpi.h>
 12#include <linux/device.h>
 13#include <linux/fs.h>
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/string.h>
 17#include <linux/sysfs.h>
 18#include <linux/types.h>
 19#include <linux/wmi.h>
 20
 21#define WMI_BMOF_GUID "05901221-D566-11D1-B2F0-00A0C9062910"
 22
 23static ssize_t bmof_read(struct file *filp, struct kobject *kobj, const struct bin_attribute *attr,
 24			 char *buf, loff_t off, size_t count)
 25{
 26	struct device *dev = kobj_to_dev(kobj);
 27	union acpi_object *obj = dev_get_drvdata(dev);
 28
 29	return memory_read_from_buffer(buf, count, &off, obj->buffer.pointer, obj->buffer.length);
 30}
 31
 32static const BIN_ATTR_ADMIN_RO(bmof, 0);
 33
 34static const struct bin_attribute * const bmof_attrs[] = {
 35	&bin_attr_bmof,
 36	NULL
 37};
 38
 39static size_t bmof_bin_size(struct kobject *kobj, const struct bin_attribute *attr, int n)
 40{
 41	struct device *dev = kobj_to_dev(kobj);
 42	union acpi_object *obj = dev_get_drvdata(dev);
 43
 44	return obj->buffer.length;
 45}
 46
 47static const struct attribute_group bmof_group = {
 48	.bin_size = bmof_bin_size,
 49	.bin_attrs = bmof_attrs,
 50};
 51
 52static const struct attribute_group *bmof_groups[] = {
 53	&bmof_group,
 54	NULL
 55};
 56
 57static int wmi_bmof_probe(struct wmi_device *wdev, const void *context)
 58{
 59	union acpi_object *obj;
 60
 61	obj = wmidev_block_query(wdev, 0);
 62	if (!obj) {
 63		dev_err(&wdev->dev, "failed to read Binary MOF\n");
 64		return -EIO;
 65	}
 66
 67	if (obj->type != ACPI_TYPE_BUFFER) {
 68		dev_err(&wdev->dev, "Binary MOF is not a buffer\n");
 69		kfree(obj);
 70		return -EIO;
 71	}
 72
 73	dev_set_drvdata(&wdev->dev, obj);
 74
 75	return 0;
 76}
 77
 78static void wmi_bmof_remove(struct wmi_device *wdev)
 79{
 80	union acpi_object *obj = dev_get_drvdata(&wdev->dev);
 81
 82	kfree(obj);
 83}
 84
 85static const struct wmi_device_id wmi_bmof_id_table[] = {
 86	{ .guid_string = WMI_BMOF_GUID },
 87	{ },
 88};
 89
 90static struct wmi_driver wmi_bmof_driver = {
 91	.driver = {
 92		.name = "wmi-bmof",
 93		.dev_groups = bmof_groups,
 94	},
 95	.probe = wmi_bmof_probe,
 96	.remove = wmi_bmof_remove,
 97	.id_table = wmi_bmof_id_table,
 98	.no_singleton = true,
 99};
100
101module_wmi_driver(wmi_bmof_driver);
102
103MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
104MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
105MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
106MODULE_LICENSE("GPL");