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
23 struct bmof_priv {
24 union acpi_object *bmofdata;
25 struct bin_attribute bmof_bin_attr;
26 };
27
read_bmof(struct file * filp,struct kobject * kobj,struct bin_attribute * attr,char * buf,loff_t off,size_t count)28 static 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
wmi_bmof_probe(struct wmi_device * wdev,const void * context)37 static 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
wmi_bmof_remove(struct wmi_device * wdev)77 static 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
85 static const struct wmi_device_id wmi_bmof_id_table[] = {
86 { .guid_string = WMI_BMOF_GUID },
87 { },
88 };
89
90 static 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 };
98
99 module_wmi_driver(wmi_bmof_driver);
100
101 MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
102 MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
103 MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
104 MODULE_LICENSE("GPL");
105