1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Functions corresponding to SET methods under BIOS attributes interface GUID for use
4  * with dell-wmi-sysman
5  *
6  *  Copyright (c) 2020 Dell Inc.
7  */
8 
9 #include <linux/wmi.h>
10 #include "dell-wmi-sysman.h"
11 
12 #define SETDEFAULTVALUES_METHOD_ID					0x02
13 #define SETBIOSDEFAULTS_METHOD_ID					0x03
14 #define SETATTRIBUTE_METHOD_ID						0x04
15 
16 static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
17 					int method_id)
18 {
19 	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
20 	struct acpi_buffer input;
21 	union acpi_object *obj;
22 	acpi_status status;
23 	int ret = -EIO;
24 
25 	input.length =  (acpi_size) size;
26 	input.pointer = in_args;
27 	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
28 	if (ACPI_FAILURE(status))
29 		return -EIO;
30 	obj = (union acpi_object *)output.pointer;
31 	if (obj->type == ACPI_TYPE_INTEGER)
32 		ret = obj->integer.value;
33 
34 	if (wmi_priv.pending_changes == 0) {
35 		wmi_priv.pending_changes = 1;
36 		/* let userland know it may need to check reboot pending again */
37 		kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
38 	}
39 	kfree(output.pointer);
40 	return map_wmi_error(ret);
41 }
42 
43 /**
44  * set_attribute() - Update an attribute value
45  * @a_name: The attribute name
46  * @a_value: The attribute value
47  *
48  * Sets an attribute to new value
49  */
50 int set_attribute(const char *a_name, const char *a_value)
51 {
52 	size_t security_area_size, buffer_size;
53 	size_t a_name_size, a_value_size;
54 	char *buffer = NULL, *start;
55 	int ret;
56 
57 	mutex_lock(&wmi_priv.mutex);
58 	if (!wmi_priv.bios_attr_wdev) {
59 		ret = -ENODEV;
60 		goto out;
61 	}
62 
63 	/* build/calculate buffer */
64 	security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
65 	a_name_size = calculate_string_buffer(a_name);
66 	a_value_size = calculate_string_buffer(a_value);
67 	buffer_size = security_area_size + a_name_size + a_value_size;
68 	buffer = kzalloc(buffer_size, GFP_KERNEL);
69 	if (!buffer) {
70 		ret = -ENOMEM;
71 		goto out;
72 	}
73 
74 	/* build security area */
75 	populate_security_buffer(buffer, wmi_priv.current_admin_password);
76 
77 	/* build variables to set */
78 	start = buffer + security_area_size;
79 	ret = populate_string_buffer(start, a_name_size, a_name);
80 	if (ret < 0)
81 		goto out;
82 	start += ret;
83 	ret = populate_string_buffer(start, a_value_size, a_value);
84 	if (ret < 0)
85 		goto out;
86 
87 	print_hex_dump_bytes("set attribute data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
88 	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
89 					    buffer, buffer_size,
90 					    SETATTRIBUTE_METHOD_ID);
91 	if (ret == -EOPNOTSUPP)
92 		dev_err(&wmi_priv.bios_attr_wdev->dev, "admin password must be configured\n");
93 	else if (ret == -EACCES)
94 		dev_err(&wmi_priv.bios_attr_wdev->dev, "invalid password\n");
95 
96 out:
97 	kfree(buffer);
98 	mutex_unlock(&wmi_priv.mutex);
99 	return ret;
100 }
101 
102 /**
103  * set_bios_defaults() - Resets BIOS defaults
104  * @deftype: the type of BIOS value reset to issue.
105  *
106  * Resets BIOS defaults
107  */
108 int set_bios_defaults(u8 deftype)
109 {
110 	size_t security_area_size, buffer_size;
111 	size_t integer_area_size = sizeof(u8);
112 	char *buffer = NULL;
113 	u8 *defaultType;
114 	int ret;
115 
116 	mutex_lock(&wmi_priv.mutex);
117 	if (!wmi_priv.bios_attr_wdev) {
118 		ret = -ENODEV;
119 		goto out;
120 	}
121 
122 	security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
123 	buffer_size = security_area_size + integer_area_size;
124 	buffer = kzalloc(buffer_size, GFP_KERNEL);
125 	if (!buffer) {
126 		ret = -ENOMEM;
127 		goto out;
128 	}
129 
130 	/* build security area */
131 	populate_security_buffer(buffer, wmi_priv.current_admin_password);
132 
133 	defaultType = buffer + security_area_size;
134 	*defaultType = deftype;
135 
136 	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
137 					    SETBIOSDEFAULTS_METHOD_ID);
138 	if (ret)
139 		dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d\n", ret);
140 
141 	kfree(buffer);
142 out:
143 	mutex_unlock(&wmi_priv.mutex);
144 	return ret;
145 }
146 
147 static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
148 {
149 	mutex_lock(&wmi_priv.mutex);
150 	wmi_priv.bios_attr_wdev = wdev;
151 	mutex_unlock(&wmi_priv.mutex);
152 	return 0;
153 }
154 
155 static void bios_attr_set_interface_remove(struct wmi_device *wdev)
156 {
157 	mutex_lock(&wmi_priv.mutex);
158 	wmi_priv.bios_attr_wdev = NULL;
159 	mutex_unlock(&wmi_priv.mutex);
160 }
161 
162 static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
163 	{ .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
164 	{ },
165 };
166 static struct wmi_driver bios_attr_set_interface_driver = {
167 	.driver = {
168 		.name = DRIVER_NAME
169 	},
170 	.probe = bios_attr_set_interface_probe,
171 	.remove = bios_attr_set_interface_remove,
172 	.id_table = bios_attr_set_interface_id_table,
173 };
174 
175 int init_bios_attr_set_interface(void)
176 {
177 	return wmi_driver_register(&bios_attr_set_interface_driver);
178 }
179 
180 void exit_bios_attr_set_interface(void)
181 {
182 	wmi_driver_unregister(&bios_attr_set_interface_driver);
183 }
184 
185 MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
186