xref: /openbmc/u-boot/fs/cbfs/cbfs.c (revision 224f7452) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
4  */
5 
6 #include <common.h>
7 #include <cbfs.h>
8 #include <malloc.h>
9 #include <asm/byteorder.h>
10 
11 enum cbfs_result file_cbfs_result;
12 
13 const char *file_cbfs_error(void)
14 {
15 	switch (file_cbfs_result) {
16 	case CBFS_SUCCESS:
17 		return "Success";
18 	case CBFS_NOT_INITIALIZED:
19 		return "CBFS not initialized";
20 	case CBFS_BAD_HEADER:
21 		return "Bad CBFS header";
22 	case CBFS_BAD_FILE:
23 		return "Bad CBFS file";
24 	case CBFS_FILE_NOT_FOUND:
25 		return "File not found";
26 	default:
27 		return "Unknown";
28 	}
29 }
30 
31 
32 static const u32 good_magic = 0x4f524243;
33 static const u8 good_file_magic[] = "LARCHIVE";
34 
35 
36 static int initialized;
37 static struct cbfs_header cbfs_header;
38 static struct cbfs_cachenode *file_cache;
39 
40 /* Do endian conversion on the CBFS header structure. */
41 static void swap_header(struct cbfs_header *dest, struct cbfs_header *src)
42 {
43 	dest->magic = be32_to_cpu(src->magic);
44 	dest->version = be32_to_cpu(src->version);
45 	dest->rom_size = be32_to_cpu(src->rom_size);
46 	dest->boot_block_size = be32_to_cpu(src->boot_block_size);
47 	dest->align = be32_to_cpu(src->align);
48 	dest->offset = be32_to_cpu(src->offset);
49 }
50 
51 /* Do endian conversion on a CBFS file header. */
52 static void swap_file_header(struct cbfs_fileheader *dest,
53 			     const struct cbfs_fileheader *src)
54 {
55 	memcpy(&dest->magic, &src->magic, sizeof(dest->magic));
56 	dest->len = be32_to_cpu(src->len);
57 	dest->type = be32_to_cpu(src->type);
58 	dest->checksum = be32_to_cpu(src->checksum);
59 	dest->offset = be32_to_cpu(src->offset);
60 }
61 
62 /*
63  * Given a starting position in memory, scan forward, bounded by a size, and
64  * find the next valid CBFS file. No memory is allocated by this function. The
65  * caller is responsible for allocating space for the new file structure.
66  *
67  * @param start		The location in memory to start from.
68  * @param size		The size of the memory region to search.
69  * @param align		The alignment boundaries to check on.
70  * @param newNode	A pointer to the file structure to load.
71  * @param used		A pointer to the count of of bytes scanned through,
72  *			including the file if one is found.
73  *
74  * @return 1 if a file is found, 0 if one isn't.
75  */
76 static int file_cbfs_next_file(u8 *start, u32 size, u32 align,
77 			       struct cbfs_cachenode *newNode, u32 *used)
78 {
79 	struct cbfs_fileheader header;
80 
81 	*used = 0;
82 
83 	while (size >= align) {
84 		const struct cbfs_fileheader *fileHeader =
85 			(const struct cbfs_fileheader *)start;
86 		u32 name_len;
87 		u32 step;
88 
89 		/* Check if there's a file here. */
90 		if (memcmp(good_file_magic, &(fileHeader->magic),
91 				sizeof(fileHeader->magic))) {
92 			*used += align;
93 			size -= align;
94 			start += align;
95 			continue;
96 		}
97 
98 		swap_file_header(&header, fileHeader);
99 		if (header.offset < sizeof(struct cbfs_fileheader)) {
100 			file_cbfs_result = CBFS_BAD_FILE;
101 			return -1;
102 		}
103 		newNode->next = NULL;
104 		newNode->type = header.type;
105 		newNode->data = start + header.offset;
106 		newNode->data_length = header.len;
107 		name_len = header.offset - sizeof(struct cbfs_fileheader);
108 		newNode->name = (char *)fileHeader +
109 				sizeof(struct cbfs_fileheader);
110 		newNode->name_length = name_len;
111 		newNode->checksum = header.checksum;
112 
113 		step = header.len;
114 		if (step % align)
115 			step = step + align - step % align;
116 
117 		*used += step;
118 		return 1;
119 	}
120 	return 0;
121 }
122 
123 /* Look through a CBFS instance and copy file metadata into regular memory. */
124 static void file_cbfs_fill_cache(u8 *start, u32 size, u32 align)
125 {
126 	struct cbfs_cachenode *cache_node;
127 	struct cbfs_cachenode *newNode;
128 	struct cbfs_cachenode **cache_tail = &file_cache;
129 
130 	/* Clear out old information. */
131 	cache_node = file_cache;
132 	while (cache_node) {
133 		struct cbfs_cachenode *oldNode = cache_node;
134 		cache_node = cache_node->next;
135 		free(oldNode);
136 	}
137 	file_cache = NULL;
138 
139 	while (size >= align) {
140 		int result;
141 		u32 used;
142 
143 		newNode = (struct cbfs_cachenode *)
144 				malloc(sizeof(struct cbfs_cachenode));
145 		result = file_cbfs_next_file(start, size, align,
146 			newNode, &used);
147 
148 		if (result < 0) {
149 			free(newNode);
150 			return;
151 		} else if (result == 0) {
152 			free(newNode);
153 			break;
154 		}
155 		*cache_tail = newNode;
156 		cache_tail = &newNode->next;
157 
158 		size -= used;
159 		start += used;
160 	}
161 	file_cbfs_result = CBFS_SUCCESS;
162 }
163 
164 /* Get the CBFS header out of the ROM and do endian conversion. */
165 static int file_cbfs_load_header(uintptr_t end_of_rom,
166 				 struct cbfs_header *header)
167 {
168 	struct cbfs_header *header_in_rom;
169 	int32_t offset = *(u32 *)(end_of_rom - 3);
170 
171 	header_in_rom = (struct cbfs_header *)(end_of_rom + offset + 1);
172 	swap_header(header, header_in_rom);
173 
174 	if (header->magic != good_magic || header->offset >
175 			header->rom_size - header->boot_block_size) {
176 		file_cbfs_result = CBFS_BAD_HEADER;
177 		return 1;
178 	}
179 	return 0;
180 }
181 
182 void file_cbfs_init(uintptr_t end_of_rom)
183 {
184 	u8 *start_of_rom;
185 	initialized = 0;
186 
187 	if (file_cbfs_load_header(end_of_rom, &cbfs_header))
188 		return;
189 
190 	start_of_rom = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);
191 
192 	file_cbfs_fill_cache(start_of_rom, cbfs_header.rom_size,
193 			     cbfs_header.align);
194 	if (file_cbfs_result == CBFS_SUCCESS)
195 		initialized = 1;
196 }
197 
198 const struct cbfs_header *file_cbfs_get_header(void)
199 {
200 	if (initialized) {
201 		file_cbfs_result = CBFS_SUCCESS;
202 		return &cbfs_header;
203 	} else {
204 		file_cbfs_result = CBFS_NOT_INITIALIZED;
205 		return NULL;
206 	}
207 }
208 
209 const struct cbfs_cachenode *file_cbfs_get_first(void)
210 {
211 	if (!initialized) {
212 		file_cbfs_result = CBFS_NOT_INITIALIZED;
213 		return NULL;
214 	} else {
215 		file_cbfs_result = CBFS_SUCCESS;
216 		return file_cache;
217 	}
218 }
219 
220 void file_cbfs_get_next(const struct cbfs_cachenode **file)
221 {
222 	if (!initialized) {
223 		file_cbfs_result = CBFS_NOT_INITIALIZED;
224 		file = NULL;
225 		return;
226 	}
227 
228 	if (*file)
229 		*file = (*file)->next;
230 	file_cbfs_result = CBFS_SUCCESS;
231 }
232 
233 const struct cbfs_cachenode *file_cbfs_find(const char *name)
234 {
235 	struct cbfs_cachenode *cache_node = file_cache;
236 
237 	if (!initialized) {
238 		file_cbfs_result = CBFS_NOT_INITIALIZED;
239 		return NULL;
240 	}
241 
242 	while (cache_node) {
243 		if (!strcmp(name, cache_node->name))
244 			break;
245 		cache_node = cache_node->next;
246 	}
247 	if (!cache_node)
248 		file_cbfs_result = CBFS_FILE_NOT_FOUND;
249 	else
250 		file_cbfs_result = CBFS_SUCCESS;
251 
252 	return cache_node;
253 }
254 
255 const struct cbfs_cachenode *file_cbfs_find_uncached(uintptr_t end_of_rom,
256 						     const char *name)
257 {
258 	u8 *start;
259 	u32 size;
260 	u32 align;
261 	static struct cbfs_cachenode node;
262 
263 	if (file_cbfs_load_header(end_of_rom, &cbfs_header))
264 		return NULL;
265 
266 	start = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);
267 	size = cbfs_header.rom_size;
268 	align = cbfs_header.align;
269 
270 	while (size >= align) {
271 		int result;
272 		u32 used;
273 
274 		result = file_cbfs_next_file(start, size, align, &node, &used);
275 
276 		if (result < 0)
277 			return NULL;
278 		else if (result == 0)
279 			break;
280 
281 		if (!strcmp(name, node.name))
282 			return &node;
283 
284 		size -= used;
285 		start += used;
286 	}
287 	file_cbfs_result = CBFS_FILE_NOT_FOUND;
288 	return NULL;
289 }
290 
291 const char *file_cbfs_name(const struct cbfs_cachenode *file)
292 {
293 	file_cbfs_result = CBFS_SUCCESS;
294 	return file->name;
295 }
296 
297 u32 file_cbfs_size(const struct cbfs_cachenode *file)
298 {
299 	file_cbfs_result = CBFS_SUCCESS;
300 	return file->data_length;
301 }
302 
303 u32 file_cbfs_type(const struct cbfs_cachenode *file)
304 {
305 	file_cbfs_result = CBFS_SUCCESS;
306 	return file->type;
307 }
308 
309 long file_cbfs_read(const struct cbfs_cachenode *file, void *buffer,
310 		    unsigned long maxsize)
311 {
312 	u32 size;
313 
314 	size = file->data_length;
315 	if (maxsize && size > maxsize)
316 		size = maxsize;
317 
318 	memcpy(buffer, file->data, size);
319 
320 	file_cbfs_result = CBFS_SUCCESS;
321 	return size;
322 }
323