2 * Dell WMI descriptor driver
4 * Copyright (C) 2017 Dell Inc. All Rights Reserved.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/acpi.h>
19 #include <linux/list.h>
20 #include <linux/module.h>
21 #include <linux/wmi.h>
22 #include "dell-wmi-descriptor.h"
24 #define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
26 struct descriptor_priv {
27 struct list_head list;
28 u32 interface_version;
32 static int descriptor_valid = -EPROBE_DEFER;
33 static LIST_HEAD(wmi_list);
34 static DEFINE_MUTEX(list_mutex);
36 int dell_wmi_get_descriptor_valid(void)
38 if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
41 return descriptor_valid;
43 EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
45 bool dell_wmi_get_interface_version(u32 *version)
47 struct descriptor_priv *priv;
50 mutex_lock(&list_mutex);
51 priv = list_first_entry_or_null(&wmi_list,
52 struct descriptor_priv,
55 *version = priv->interface_version;
58 mutex_unlock(&list_mutex);
61 EXPORT_SYMBOL_GPL(dell_wmi_get_interface_version);
63 bool dell_wmi_get_size(u32 *size)
65 struct descriptor_priv *priv;
68 mutex_lock(&list_mutex);
69 priv = list_first_entry_or_null(&wmi_list,
70 struct descriptor_priv,
76 mutex_unlock(&list_mutex);
79 EXPORT_SYMBOL_GPL(dell_wmi_get_size);
81 bool dell_wmi_get_hotfix(u32 *hotfix)
83 struct descriptor_priv *priv;
86 mutex_lock(&list_mutex);
87 priv = list_first_entry_or_null(&wmi_list,
88 struct descriptor_priv,
91 *hotfix = priv->hotfix;
94 mutex_unlock(&list_mutex);
97 EXPORT_SYMBOL_GPL(dell_wmi_get_hotfix);
100 * Descriptor buffer is 128 byte long and contains:
102 * Name Offset Length Value
103 * Vendor Signature 0 4 "DELL"
104 * Object Signature 4 4 " WMI"
105 * WMI Interface Version 8 4 <version>
106 * WMI buffer length 12 4 <length>
107 * WMI hotfix number 16 4 <hotfix>
109 static int dell_wmi_descriptor_probe(struct wmi_device *wdev,
112 union acpi_object *obj = NULL;
113 struct descriptor_priv *priv;
117 obj = wmidev_block_query(wdev, 0);
119 dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");
124 if (obj->type != ACPI_TYPE_BUFFER) {
125 dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
127 descriptor_valid = ret;
131 /* Although it's not technically a failure, this would lead to
132 * unexpected behavior
134 if (obj->buffer.length != 128) {
136 "Dell descriptor buffer has unexpected length (%d)\n",
139 descriptor_valid = ret;
143 buffer = (u32 *)obj->buffer.pointer;
145 if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
146 dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
149 descriptor_valid = ret;
152 descriptor_valid = 0;
154 if (buffer[2] != 0 && buffer[2] != 1)
155 dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
156 (unsigned long) buffer[2]);
158 priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),
166 priv->interface_version = buffer[2];
167 priv->size = buffer[3];
168 priv->hotfix = buffer[4];
170 dev_set_drvdata(&wdev->dev, priv);
171 mutex_lock(&list_mutex);
172 list_add_tail(&priv->list, &wmi_list);
173 mutex_unlock(&list_mutex);
175 dev_dbg(&wdev->dev, "Detected Dell WMI interface version %lu, buffer size %lu, hotfix %lu\n",
176 (unsigned long) priv->interface_version,
177 (unsigned long) priv->size,
178 (unsigned long) priv->hotfix);
185 static int dell_wmi_descriptor_remove(struct wmi_device *wdev)
187 struct descriptor_priv *priv = dev_get_drvdata(&wdev->dev);
189 mutex_lock(&list_mutex);
190 list_del(&priv->list);
191 mutex_unlock(&list_mutex);
195 static const struct wmi_device_id dell_wmi_descriptor_id_table[] = {
196 { .guid_string = DELL_WMI_DESCRIPTOR_GUID },
200 static struct wmi_driver dell_wmi_descriptor_driver = {
202 .name = "dell-wmi-descriptor",
204 .probe = dell_wmi_descriptor_probe,
205 .remove = dell_wmi_descriptor_remove,
206 .id_table = dell_wmi_descriptor_id_table,
209 module_wmi_driver(dell_wmi_descriptor_driver);
211 MODULE_DEVICE_TABLE(wmi, dell_wmi_descriptor_id_table);
212 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
213 MODULE_DESCRIPTION("Dell WMI descriptor driver");
214 MODULE_LICENSE("GPL");