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7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/acpi.h>
11#include <linux/list.h>
12#include <linux/module.h>
13#include <linux/wmi.h>
14#include "dell-wmi-descriptor.h"
15
16#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
17
18struct descriptor_priv {
19 struct list_head list;
20 u32 interface_version;
21 u32 size;
22 u32 hotfix;
23};
24static int descriptor_valid = -EPROBE_DEFER;
25static LIST_HEAD(wmi_list);
26static DEFINE_MUTEX(list_mutex);
27
28int dell_wmi_get_descriptor_valid(void)
29{
30 if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
31 return -ENODEV;
32
33 return descriptor_valid;
34}
35EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
36
37bool dell_wmi_get_interface_version(u32 *version)
38{
39 struct descriptor_priv *priv;
40 bool ret = false;
41
42 mutex_lock(&list_mutex);
43 priv = list_first_entry_or_null(&wmi_list,
44 struct descriptor_priv,
45 list);
46 if (priv) {
47 *version = priv->interface_version;
48 ret = true;
49 }
50 mutex_unlock(&list_mutex);
51 return ret;
52}
53EXPORT_SYMBOL_GPL(dell_wmi_get_interface_version);
54
55bool dell_wmi_get_size(u32 *size)
56{
57 struct descriptor_priv *priv;
58 bool ret = false;
59
60 mutex_lock(&list_mutex);
61 priv = list_first_entry_or_null(&wmi_list,
62 struct descriptor_priv,
63 list);
64 if (priv) {
65 *size = priv->size;
66 ret = true;
67 }
68 mutex_unlock(&list_mutex);
69 return ret;
70}
71EXPORT_SYMBOL_GPL(dell_wmi_get_size);
72
73bool dell_wmi_get_hotfix(u32 *hotfix)
74{
75 struct descriptor_priv *priv;
76 bool ret = false;
77
78 mutex_lock(&list_mutex);
79 priv = list_first_entry_or_null(&wmi_list,
80 struct descriptor_priv,
81 list);
82 if (priv) {
83 *hotfix = priv->hotfix;
84 ret = true;
85 }
86 mutex_unlock(&list_mutex);
87 return ret;
88}
89EXPORT_SYMBOL_GPL(dell_wmi_get_hotfix);
90
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98
99
100
101static int dell_wmi_descriptor_probe(struct wmi_device *wdev,
102 const void *context)
103{
104 union acpi_object *obj = NULL;
105 struct descriptor_priv *priv;
106 u32 *buffer;
107 int ret;
108
109 obj = wmidev_block_query(wdev, 0);
110 if (!obj) {
111 dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");
112 ret = -EIO;
113 goto out;
114 }
115
116 if (obj->type != ACPI_TYPE_BUFFER) {
117 dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
118 ret = -EINVAL;
119 descriptor_valid = ret;
120 goto out;
121 }
122
123
124
125
126 if (obj->buffer.length != 128) {
127 dev_err(&wdev->dev,
128 "Dell descriptor buffer has unexpected length (%d)\n",
129 obj->buffer.length);
130 ret = -EINVAL;
131 descriptor_valid = ret;
132 goto out;
133 }
134
135 buffer = (u32 *)obj->buffer.pointer;
136
137 if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
138 dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
139 buffer);
140 ret = -EINVAL;
141 descriptor_valid = ret;
142 goto out;
143 }
144 descriptor_valid = 0;
145
146 if (buffer[2] != 0 && buffer[2] != 1)
147 dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
148 (unsigned long) buffer[2]);
149
150 priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),
151 GFP_KERNEL);
152
153 if (!priv) {
154 ret = -ENOMEM;
155 goto out;
156 }
157
158 priv->interface_version = buffer[2];
159 priv->size = buffer[3];
160 priv->hotfix = buffer[4];
161 ret = 0;
162 dev_set_drvdata(&wdev->dev, priv);
163 mutex_lock(&list_mutex);
164 list_add_tail(&priv->list, &wmi_list);
165 mutex_unlock(&list_mutex);
166
167 dev_dbg(&wdev->dev, "Detected Dell WMI interface version %lu, buffer size %lu, hotfix %lu\n",
168 (unsigned long) priv->interface_version,
169 (unsigned long) priv->size,
170 (unsigned long) priv->hotfix);
171
172out:
173 kfree(obj);
174 return ret;
175}
176
177static void dell_wmi_descriptor_remove(struct wmi_device *wdev)
178{
179 struct descriptor_priv *priv = dev_get_drvdata(&wdev->dev);
180
181 mutex_lock(&list_mutex);
182 list_del(&priv->list);
183 mutex_unlock(&list_mutex);
184}
185
186static const struct wmi_device_id dell_wmi_descriptor_id_table[] = {
187 { .guid_string = DELL_WMI_DESCRIPTOR_GUID },
188 { },
189};
190
191static struct wmi_driver dell_wmi_descriptor_driver = {
192 .driver = {
193 .name = "dell-wmi-descriptor",
194 },
195 .probe = dell_wmi_descriptor_probe,
196 .remove = dell_wmi_descriptor_remove,
197 .id_table = dell_wmi_descriptor_id_table,
198};
199
200module_wmi_driver(dell_wmi_descriptor_driver);
201
202MODULE_DEVICE_TABLE(wmi, dell_wmi_descriptor_id_table);
203MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
204MODULE_DESCRIPTION("Dell WMI descriptor driver");
205MODULE_LICENSE("GPL");
206
