1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * EFI device path interface
4 *
5 * Copyright (c) 2017 Leif Lindholm
6 */
7
8 #include <common.h>
9 #include <efi_loader.h>
10
11 const efi_guid_t efi_guid_device_path_utilities_protocol =
12 EFI_DEVICE_PATH_UTILITIES_PROTOCOL_GUID;
13
14 /*
15 * Get size of a device path.
16 *
17 * This function implements the GetDevicePathSize service of the device path
18 * utilities protocol. The device path length includes the end of path tag
19 * which may be an instance end.
20 *
21 * See the Unified Extensible Firmware Interface (UEFI) specification
22 * for details.
23 *
24 * @device_path device path
25 * @return size in bytes
26 */
get_device_path_size(const struct efi_device_path * device_path)27 static efi_uintn_t EFIAPI get_device_path_size(
28 const struct efi_device_path *device_path)
29 {
30 efi_uintn_t sz = 0;
31
32 EFI_ENTRY("%pD", device_path);
33 /* size includes the END node: */
34 if (device_path)
35 sz = efi_dp_size(device_path) + sizeof(struct efi_device_path);
36 return EFI_EXIT(sz);
37 }
38
39 /*
40 * Duplicate a device path.
41 *
42 * This function implements the DuplicateDevicePath service of the device path
43 * utilities protocol.
44 *
45 * The UEFI spec does not indicate what happens to the end tag. We follow the
46 * EDK2 logic: In case the device path ends with an end of instance tag, the
47 * copy will also end with an end of instance tag.
48 *
49 * See the Unified Extensible Firmware Interface (UEFI) specification
50 * for details.
51 *
52 * @device_path device path
53 * @return copy of the device path
54 */
duplicate_device_path(const struct efi_device_path * device_path)55 static struct efi_device_path * EFIAPI duplicate_device_path(
56 const struct efi_device_path *device_path)
57 {
58 EFI_ENTRY("%pD", device_path);
59 return EFI_EXIT(efi_dp_dup(device_path));
60 }
61
62 /*
63 * Append device path.
64 *
65 * This function implements the AppendDevicePath service of the device path
66 * utilities protocol.
67 *
68 * See the Unified Extensible Firmware Interface (UEFI) specification
69 * for details.
70 *
71 * @src1 1st device path
72 * @src2 2nd device path
73 * @return concatenated device path
74 */
append_device_path(const struct efi_device_path * src1,const struct efi_device_path * src2)75 static struct efi_device_path * EFIAPI append_device_path(
76 const struct efi_device_path *src1,
77 const struct efi_device_path *src2)
78 {
79 EFI_ENTRY("%pD, %pD", src1, src2);
80 return EFI_EXIT(efi_dp_append(src1, src2));
81 }
82
83 /*
84 * Append device path node.
85 *
86 * This function implements the AppendDeviceNode service of the device path
87 * utilities protocol.
88 *
89 * See the Unified Extensible Firmware Interface (UEFI) specification
90 * for details.
91 *
92 * @device_path device path
93 * @device_node device node
94 * @return concatenated device path
95 */
append_device_node(const struct efi_device_path * device_path,const struct efi_device_path * device_node)96 static struct efi_device_path * EFIAPI append_device_node(
97 const struct efi_device_path *device_path,
98 const struct efi_device_path *device_node)
99 {
100 EFI_ENTRY("%pD, %p", device_path, device_node);
101 return EFI_EXIT(efi_dp_append_node(device_path, device_node));
102 }
103
104 /*
105 * Append device path instance.
106 *
107 * This function implements the AppendDevicePathInstance service of the device
108 * path utilities protocol.
109 *
110 * See the Unified Extensible Firmware Interface (UEFI) specification
111 * for details.
112 *
113 * @device_path 1st device path
114 * @device_path_instance 2nd device path
115 * @return concatenated device path
116 */
append_device_path_instance(const struct efi_device_path * device_path,const struct efi_device_path * device_path_instance)117 static struct efi_device_path * EFIAPI append_device_path_instance(
118 const struct efi_device_path *device_path,
119 const struct efi_device_path *device_path_instance)
120 {
121 EFI_ENTRY("%pD, %pD", device_path, device_path_instance);
122 return EFI_EXIT(efi_dp_append_instance(device_path,
123 device_path_instance));
124 }
125
126 /*
127 * Get next device path instance.
128 *
129 * This function implements the GetNextDevicePathInstance service of the device
130 * path utilities protocol.
131 *
132 * See the Unified Extensible Firmware Interface (UEFI) specification
133 * for details.
134 *
135 * @device_path_instance next device path instance
136 * @device_path_instance_size size of the device path instance
137 * @return concatenated device path
138 */
get_next_device_path_instance(struct efi_device_path ** device_path_instance,efi_uintn_t * device_path_instance_size)139 static struct efi_device_path * EFIAPI get_next_device_path_instance(
140 struct efi_device_path **device_path_instance,
141 efi_uintn_t *device_path_instance_size)
142 {
143 EFI_ENTRY("%pD, %p", device_path_instance, device_path_instance_size);
144 return EFI_EXIT(efi_dp_get_next_instance(device_path_instance,
145 device_path_instance_size));
146 }
147
148 /*
149 * Check if a device path contains more than one instance.
150 *
151 * This function implements the AppendDeviceNode service of the device path
152 * utilities protocol.
153 *
154 * See the Unified Extensible Firmware Interface (UEFI) specification
155 * for details.
156 *
157 * @device_path device path
158 * @device_node device node
159 * @return concatenated device path
160 */
is_device_path_multi_instance(const struct efi_device_path * device_path)161 static bool EFIAPI is_device_path_multi_instance(
162 const struct efi_device_path *device_path)
163 {
164 EFI_ENTRY("%pD", device_path);
165 return EFI_EXIT(efi_dp_is_multi_instance(device_path));
166 }
167
168 /*
169 * Create device node.
170 *
171 * This function implements the CreateDeviceNode service of the device path
172 * utilities protocol.
173 *
174 * See the Unified Extensible Firmware Interface (UEFI) specification
175 * for details.
176 *
177 * @node_type node type
178 * @node_sub_type node sub type
179 * @node_length node length
180 * @return device path node
181 */
create_device_node(uint8_t node_type,uint8_t node_sub_type,uint16_t node_length)182 static struct efi_device_path * EFIAPI create_device_node(
183 uint8_t node_type, uint8_t node_sub_type, uint16_t node_length)
184 {
185 EFI_ENTRY("%u, %u, %u", node_type, node_sub_type, node_length);
186 return EFI_EXIT(efi_dp_create_device_node(node_type, node_sub_type,
187 node_length));
188 }
189
190 const struct efi_device_path_utilities_protocol efi_device_path_utilities = {
191 .get_device_path_size = get_device_path_size,
192 .duplicate_device_path = duplicate_device_path,
193 .append_device_path = append_device_path,
194 .append_device_node = append_device_node,
195 .append_device_path_instance = append_device_path_instance,
196 .get_next_device_path_instance = get_next_device_path_instance,
197 .is_device_path_multi_instance = is_device_path_multi_instance,
198 .create_device_node = create_device_node,
199 };
200