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
23struct bmof_priv {
24	union acpi_object *bmofdata;
25	struct bin_attribute bmof_bin_attr;
26};
27
28static ssize_t read_bmof(struct file *filp, struct kobject *kobj, struct bin_attribute *attr,
29			 char *buf, loff_t off, size_t count)
30{
31	struct bmof_priv *priv = container_of(attr, struct bmof_priv, bmof_bin_attr);
32
33	return memory_read_from_buffer(buf, count, &off, priv->bmofdata->buffer.pointer,
34				       priv->bmofdata->buffer.length);
35}
36
37static int wmi_bmof_probe(struct wmi_device *wdev, const void *context)
38{
39	struct bmof_priv *priv;
40	int ret;
41
42	priv = devm_kzalloc(&wdev->dev, sizeof(struct bmof_priv), GFP_KERNEL);
43	if (!priv)
44		return -ENOMEM;
45
46	dev_set_drvdata(&wdev->dev, priv);
47
48	priv->bmofdata = wmidev_block_query(wdev, 0);
49	if (!priv->bmofdata) {
50		dev_err(&wdev->dev, "failed to read Binary MOF\n");
51		return -EIO;
52	}
53
54	if (priv->bmofdata->type != ACPI_TYPE_BUFFER) {
55		dev_err(&wdev->dev, "Binary MOF is not a buffer\n");
56		ret = -EIO;
57		goto err_free;
58	}
59
60	sysfs_bin_attr_init(&priv->bmof_bin_attr);
61	priv->bmof_bin_attr.attr.name = "bmof";
62	priv->bmof_bin_attr.attr.mode = 0400;
63	priv->bmof_bin_attr.read = read_bmof;
64	priv->bmof_bin_attr.size = priv->bmofdata->buffer.length;
65
66	ret = device_create_bin_file(&wdev->dev, &priv->bmof_bin_attr);
67	if (ret)
68		goto err_free;
69
70	return 0;
71
72 err_free:
73	kfree(priv->bmofdata);
74	return ret;
75}
76
77static void wmi_bmof_remove(struct wmi_device *wdev)
78{
79	struct bmof_priv *priv = dev_get_drvdata(&wdev->dev);
80
81	device_remove_bin_file(&wdev->dev, &priv->bmof_bin_attr);
82	kfree(priv->bmofdata);
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	},
94	.probe = wmi_bmof_probe,
95	.remove = wmi_bmof_remove,
96	.id_table = wmi_bmof_id_table,
97	.no_singleton = true,
98};
99
100module_wmi_driver(wmi_bmof_driver);
101
102MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
103MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
104MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
105MODULE_LICENSE("GPL");
106