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1 | /* |
2 | * WMI methods for use with dell-smbios | |
3 | * | |
4 | * Copyright (c) 2017 Dell Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
11 | ||
12 | #include <linux/dmi.h> | |
13 | #include <linux/list.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/mutex.h> | |
16 | #include <linux/uaccess.h> | |
17 | #include <linux/wmi.h> | |
18 | #include "dell-smbios.h" | |
19 | #include "dell-wmi-descriptor.h" | |
20 | ||
21 | static DEFINE_MUTEX(call_mutex); | |
22 | static DEFINE_MUTEX(list_mutex); | |
23 | static int wmi_supported; | |
24 | ||
25 | struct misc_bios_flags_structure { | |
26 | struct dmi_header header; | |
27 | u16 flags0; | |
28 | } __packed; | |
29 | #define FLAG_HAS_ACPI_WMI 0x02 | |
30 | ||
31 | #define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492" | |
32 | ||
33 | struct dell_wmi_extensions { | |
34 | __u32 argattrib; | |
35 | __u32 blength; | |
36 | __u8 data[]; | |
37 | } __packed; | |
38 | ||
39 | struct dell_wmi_smbios_buffer { | |
40 | struct calling_interface_buffer std; | |
41 | struct dell_wmi_extensions ext; | |
42 | } __packed; | |
43 | ||
44 | struct wmi_smbios_priv { | |
45 | struct dell_wmi_smbios_buffer *buf; | |
46 | struct list_head list; | |
47 | struct wmi_device *wdev; | |
48 | struct device *child; | |
49 | u32 req_buf_size; | |
50 | }; | |
51 | static LIST_HEAD(wmi_list); | |
52 | ||
53 | static inline struct wmi_smbios_priv *get_first_smbios_priv(void) | |
54 | { | |
55 | return list_first_entry_or_null(&wmi_list, | |
56 | struct wmi_smbios_priv, | |
57 | list); | |
58 | } | |
59 | ||
60 | static int run_smbios_call(struct wmi_device *wdev) | |
61 | { | |
62 | struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; | |
63 | struct wmi_smbios_priv *priv; | |
64 | struct acpi_buffer input; | |
65 | union acpi_object *obj; | |
66 | acpi_status status; | |
67 | ||
68 | priv = dev_get_drvdata(&wdev->dev); | |
69 | input.length = priv->req_buf_size - sizeof(u64); | |
70 | input.pointer = &priv->buf->std; | |
71 | ||
72 | dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n", | |
73 | priv->buf->std.cmd_class, priv->buf->std.cmd_select, | |
74 | priv->buf->std.input[0], priv->buf->std.input[1], | |
75 | priv->buf->std.input[2], priv->buf->std.input[3]); | |
76 | ||
77 | status = wmidev_evaluate_method(wdev, 0, 1, &input, &output); | |
78 | if (ACPI_FAILURE(status)) | |
79 | return -EIO; | |
80 | obj = (union acpi_object *)output.pointer; | |
81 | if (obj->type != ACPI_TYPE_BUFFER) { | |
82 | dev_dbg(&wdev->dev, "received type: %d\n", obj->type); | |
83 | if (obj->type == ACPI_TYPE_INTEGER) | |
84 | dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n", | |
85 | obj->integer.value); | |
86 | return -EIO; | |
87 | } | |
88 | memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length); | |
89 | dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n", | |
90 | priv->buf->std.output[0], priv->buf->std.output[1], | |
91 | priv->buf->std.output[2], priv->buf->std.output[3]); | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | int dell_smbios_wmi_call(struct calling_interface_buffer *buffer) | |
97 | { | |
98 | struct wmi_smbios_priv *priv; | |
99 | size_t difference; | |
100 | size_t size; | |
101 | int ret; | |
102 | ||
103 | mutex_lock(&call_mutex); | |
104 | priv = get_first_smbios_priv(); | |
105 | if (!priv) | |
106 | return -ENODEV; | |
107 | ||
108 | size = sizeof(struct calling_interface_buffer); | |
109 | difference = priv->req_buf_size - sizeof(u64) - size; | |
110 | ||
111 | memset(&priv->buf->ext, 0, difference); | |
112 | memcpy(&priv->buf->std, buffer, size); | |
113 | ret = run_smbios_call(priv->wdev); | |
114 | memcpy(buffer, &priv->buf->std, size); | |
115 | mutex_unlock(&call_mutex); | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
120 | static int dell_smbios_wmi_probe(struct wmi_device *wdev) | |
121 | { | |
122 | struct wmi_smbios_priv *priv; | |
123 | int count; | |
124 | int ret; | |
125 | ||
126 | if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID)) | |
127 | return -ENODEV; | |
128 | ||
129 | priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv), | |
130 | GFP_KERNEL); | |
131 | if (!priv) | |
132 | return -ENOMEM; | |
133 | ||
134 | /* WMI buffer size will be either 4k or 32k depending on machine */ | |
135 | if (!dell_wmi_get_size(&priv->req_buf_size)) | |
136 | return -EPROBE_DEFER; | |
137 | ||
138 | count = get_order(priv->req_buf_size); | |
139 | priv->buf = (void *)__get_free_pages(GFP_KERNEL, count); | |
140 | if (!priv->buf) | |
141 | return -ENOMEM; | |
142 | ||
143 | /* ID is used by dell-smbios to set priority of drivers */ | |
144 | wdev->dev.id = 1; | |
145 | ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call); | |
146 | if (ret) | |
147 | goto fail_register; | |
148 | ||
149 | priv->wdev = wdev; | |
150 | dev_set_drvdata(&wdev->dev, priv); | |
151 | mutex_lock(&list_mutex); | |
152 | list_add_tail(&priv->list, &wmi_list); | |
153 | mutex_unlock(&list_mutex); | |
154 | ||
155 | return 0; | |
156 | ||
157 | fail_register: | |
158 | free_pages((unsigned long)priv->buf, count); | |
159 | return ret; | |
160 | } | |
161 | ||
162 | static int dell_smbios_wmi_remove(struct wmi_device *wdev) | |
163 | { | |
164 | struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev); | |
165 | int count; | |
166 | ||
167 | mutex_lock(&call_mutex); | |
168 | mutex_lock(&list_mutex); | |
169 | list_del(&priv->list); | |
170 | mutex_unlock(&list_mutex); | |
171 | dell_smbios_unregister_device(&wdev->dev); | |
172 | count = get_order(priv->req_buf_size); | |
173 | free_pages((unsigned long)priv->buf, count); | |
174 | mutex_unlock(&call_mutex); | |
175 | return 0; | |
176 | } | |
177 | ||
178 | static const struct wmi_device_id dell_smbios_wmi_id_table[] = { | |
179 | { .guid_string = DELL_WMI_SMBIOS_GUID }, | |
180 | { }, | |
181 | }; | |
182 | ||
183 | static void __init parse_b1_table(const struct dmi_header *dm) | |
184 | { | |
185 | struct misc_bios_flags_structure *flags = | |
186 | container_of(dm, struct misc_bios_flags_structure, header); | |
187 | ||
188 | /* 4 bytes header, 8 bytes flags */ | |
189 | if (dm->length < 12) | |
190 | return; | |
191 | if (dm->handle != 0xb100) | |
192 | return; | |
193 | if ((flags->flags0 & FLAG_HAS_ACPI_WMI)) | |
194 | wmi_supported = 1; | |
195 | } | |
196 | ||
197 | static void __init find_b1(const struct dmi_header *dm, void *dummy) | |
198 | { | |
199 | switch (dm->type) { | |
200 | case 0xb1: /* misc bios flags */ | |
201 | parse_b1_table(dm); | |
202 | break; | |
203 | } | |
204 | } | |
205 | ||
206 | static struct wmi_driver dell_smbios_wmi_driver = { | |
207 | .driver = { | |
208 | .name = "dell-smbios", | |
209 | }, | |
210 | .probe = dell_smbios_wmi_probe, | |
211 | .remove = dell_smbios_wmi_remove, | |
212 | .id_table = dell_smbios_wmi_id_table, | |
213 | }; | |
214 | ||
215 | static int __init init_dell_smbios_wmi(void) | |
216 | { | |
217 | dmi_walk(find_b1, NULL); | |
218 | ||
219 | if (!wmi_supported) | |
220 | return -ENODEV; | |
221 | ||
222 | return wmi_driver_register(&dell_smbios_wmi_driver); | |
223 | } | |
224 | ||
225 | static void __exit exit_dell_smbios_wmi(void) | |
226 | { | |
227 | wmi_driver_unregister(&dell_smbios_wmi_driver); | |
228 | } | |
229 | ||
230 | module_init(init_dell_smbios_wmi); | |
231 | module_exit(exit_dell_smbios_wmi); | |
232 | ||
233 | MODULE_ALIAS("wmi:" DELL_WMI_SMBIOS_GUID); | |
234 | MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>"); | |
235 | MODULE_DESCRIPTION("Dell SMBIOS communications over WMI"); | |
236 | MODULE_LICENSE("GPL"); |