1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Dell WMI descriptor driver |
4 | * |
5 | * Copyright (C) 2017 Dell Inc. All Rights Reserved. |
6 | */ |
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 | |
18 | struct descriptor_priv { |
19 | struct list_head list; |
20 | u32 interface_version; |
21 | u32 size; |
22 | u32 hotfix; |
23 | }; |
24 | static int descriptor_valid = -EPROBE_DEFER; |
25 | static LIST_HEAD(wmi_list); |
26 | static DEFINE_MUTEX(list_mutex); |
27 | |
28 | int 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 | } |
35 | EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid); |
36 | |
37 | bool 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(lock: &list_mutex); |
51 | return ret; |
52 | } |
53 | EXPORT_SYMBOL_GPL(dell_wmi_get_interface_version); |
54 | |
55 | bool 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(lock: &list_mutex); |
69 | return ret; |
70 | } |
71 | EXPORT_SYMBOL_GPL(dell_wmi_get_size); |
72 | |
73 | bool 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(lock: &list_mutex); |
87 | return ret; |
88 | } |
89 | EXPORT_SYMBOL_GPL(dell_wmi_get_hotfix); |
90 | |
91 | /* |
92 | * Descriptor buffer is 128 byte long and contains: |
93 | * |
94 | * Name Offset Length Value |
95 | * Vendor Signature 0 4 "DELL" |
96 | * Object Signature 4 4 " WMI" |
97 | * WMI Interface Version 8 4 <version> |
98 | * WMI buffer length 12 4 <length> |
99 | * WMI hotfix number 16 4 <hotfix> |
100 | */ |
101 | static 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, instance: 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 | /* Although it's not technically a failure, this would lead to |
124 | * unexpected behavior |
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(dev: &wdev->dev, size: 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(dev: &wdev->dev, data: priv); |
163 | mutex_lock(&list_mutex); |
164 | list_add_tail(new: &priv->list, head: &wmi_list); |
165 | mutex_unlock(lock: &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 | |
172 | out: |
173 | kfree(objp: obj); |
174 | return ret; |
175 | } |
176 | |
177 | static void dell_wmi_descriptor_remove(struct wmi_device *wdev) |
178 | { |
179 | struct descriptor_priv *priv = dev_get_drvdata(dev: &wdev->dev); |
180 | |
181 | mutex_lock(&list_mutex); |
182 | list_del(entry: &priv->list); |
183 | mutex_unlock(lock: &list_mutex); |
184 | } |
185 | |
186 | static const struct wmi_device_id dell_wmi_descriptor_id_table[] = { |
187 | { .guid_string = DELL_WMI_DESCRIPTOR_GUID }, |
188 | { }, |
189 | }; |
190 | |
191 | static 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 | |
200 | module_wmi_driver(dell_wmi_descriptor_driver); |
201 | |
202 | MODULE_DEVICE_TABLE(wmi, dell_wmi_descriptor_id_table); |
203 | MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>" ); |
204 | MODULE_DESCRIPTION("Dell WMI descriptor driver" ); |
205 | MODULE_LICENSE("GPL" ); |
206 | |