1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Builtin firmware support */ |
3 | |
4 | #include <linux/firmware.h> |
5 | #include "../firmware.h" |
6 | |
7 | /* Only if FW_LOADER=y */ |
8 | #ifdef CONFIG_FW_LOADER |
9 | |
10 | struct builtin_fw { |
11 | char *name; |
12 | void *data; |
13 | unsigned long size; |
14 | }; |
15 | |
16 | extern struct builtin_fw __start_builtin_fw[]; |
17 | extern struct builtin_fw __end_builtin_fw[]; |
18 | |
19 | static bool fw_copy_to_prealloc_buf(struct firmware *fw, |
20 | void *buf, size_t size) |
21 | { |
22 | if (!buf) |
23 | return true; |
24 | if (size < fw->size) |
25 | return false; |
26 | memcpy(buf, fw->data, fw->size); |
27 | return true; |
28 | } |
29 | |
30 | /** |
31 | * firmware_request_builtin() - load builtin firmware |
32 | * @fw: pointer to firmware struct |
33 | * @name: name of firmware file |
34 | * |
35 | * Some use cases in the kernel have a requirement so that no memory allocator |
36 | * is involved as these calls take place early in boot process. An example is |
37 | * the x86 CPU microcode loader. In these cases all the caller wants is to see |
38 | * if the firmware was built-in and if so use it right away. This can be used |
39 | * for such cases. |
40 | * |
41 | * This looks for the firmware in the built-in kernel. Only if the kernel was |
42 | * built-in with the firmware you are looking for will this return successfully. |
43 | * |
44 | * Callers of this API do not need to use release_firmware() as the pointer to |
45 | * the firmware is expected to be provided locally on the stack of the caller. |
46 | **/ |
47 | bool firmware_request_builtin(struct firmware *fw, const char *name) |
48 | { |
49 | struct builtin_fw *b_fw; |
50 | |
51 | if (!fw) |
52 | return false; |
53 | |
54 | for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) { |
55 | if (strcmp(name, b_fw->name) == 0) { |
56 | fw->size = b_fw->size; |
57 | fw->data = b_fw->data; |
58 | return true; |
59 | } |
60 | } |
61 | |
62 | return false; |
63 | } |
64 | EXPORT_SYMBOL_NS_GPL(firmware_request_builtin, TEST_FIRMWARE); |
65 | |
66 | /** |
67 | * firmware_request_builtin_buf() - load builtin firmware into optional buffer |
68 | * @fw: pointer to firmware struct |
69 | * @name: name of firmware file |
70 | * @buf: If set this lets you use a pre-allocated buffer so that the built-in |
71 | * firmware into is copied into. This field can be NULL. It is used by |
72 | * callers such as request_firmware_into_buf() and |
73 | * request_partial_firmware_into_buf() |
74 | * @size: if buf was provided, the max size of the allocated buffer available. |
75 | * If the built-in firmware does not fit into the pre-allocated @buf this |
76 | * call will fail. |
77 | * |
78 | * This looks for the firmware in the built-in kernel. Only if the kernel was |
79 | * built-in with the firmware you are looking for will this call possibly |
80 | * succeed. If you passed a @buf the firmware will be copied into it *iff* the |
81 | * built-in firmware fits into the pre-allocated buffer size specified in |
82 | * @size. |
83 | * |
84 | * This caller is to be used internally by the firmware_loader only. |
85 | **/ |
86 | bool firmware_request_builtin_buf(struct firmware *fw, const char *name, |
87 | void *buf, size_t size) |
88 | { |
89 | if (!firmware_request_builtin(fw, name)) |
90 | return false; |
91 | |
92 | return fw_copy_to_prealloc_buf(fw, buf, size); |
93 | } |
94 | |
95 | bool firmware_is_builtin(const struct firmware *fw) |
96 | { |
97 | struct builtin_fw *b_fw; |
98 | |
99 | for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) |
100 | if (fw->data == b_fw->data) |
101 | return true; |
102 | |
103 | return false; |
104 | } |
105 | |
106 | #endif |
107 | |