xref: /openbmc/u-boot/fs/cbfs/cbfs.c (revision 29b103c7) 
1 /*
2  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
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(const struct cbfs_cachenode *) ||
100 				header.offset > header.len) {
101 			file_cbfs_result = CBFS_BAD_FILE;
102 			return -1;
103 		}
104 		newNode->next = NULL;
105 		newNode->type = header.type;
106 		newNode->data = start + header.offset;
107 		newNode->data_length = header.len;
108 		name_len = header.offset - sizeof(struct cbfs_cachenode *);
109 		newNode->name = (char *)fileHeader +
110 				sizeof(struct cbfs_cachenode *);
111 		newNode->name_length = name_len;
112 		newNode->checksum = header.checksum;
113 
114 		step = header.len;
115 		if (step % align)
116 			step = step + align - step % align;
117 
118 		*used += step;
119 		return 1;
120 	}
121 	return 0;
122 }
123 
124 /* Look through a CBFS instance and copy file metadata into regular memory. */
125 static void file_cbfs_fill_cache(u8 *start, u32 size, u32 align)
126 {
127 	struct cbfs_cachenode *cache_node;
128 	struct cbfs_cachenode *newNode;
129 	struct cbfs_cachenode **cache_tail = &file_cache;
130 
131 	/* Clear out old information. */
132 	cache_node = file_cache;
133 	while (cache_node) {
134 		struct cbfs_cachenode *oldNode = cache_node;
135 		cache_node = cache_node->next;
136 		free(oldNode);
137 	}
138 	file_cache = NULL;
139 
140 	while (size >= align) {
141 		int result;
142 		u32 used;
143 
144 		newNode = (struct cbfs_cachenode *)
145 				malloc(sizeof(struct cbfs_cachenode));
146 		result = file_cbfs_next_file(start, size, align,
147 			newNode, &used);
148 
149 		if (result < 0) {
150 			free(newNode);
151 			return;
152 		} else if (result == 0) {
153 			free(newNode);
154 			break;
155 		}
156 		*cache_tail = newNode;
157 		cache_tail = &newNode->next;
158 
159 		size -= used;
160 		start += used;
161 	}
162 	file_cbfs_result = CBFS_SUCCESS;
163 }
164 
165 /* Get the CBFS header out of the ROM and do endian conversion. */
166 static int file_cbfs_load_header(uintptr_t end_of_rom,
167 				 struct cbfs_header *header)
168 {
169 	struct cbfs_header *header_in_rom;
170 
171 	header_in_rom = (struct cbfs_header *)(uintptr_t)
172 			*(u32 *)(end_of_rom - 3);
173 	swap_header(header, header_in_rom);
174 
175 	if (header->magic != good_magic || header->offset >
176 			header->rom_size - header->boot_block_size) {
177 		file_cbfs_result = CBFS_BAD_HEADER;
178 		return 1;
179 	}
180 	return 0;
181 }
182 
183 void file_cbfs_init(uintptr_t end_of_rom)
184 {
185 	u8 *start_of_rom;
186 	initialized = 0;
187 
188 	if (file_cbfs_load_header(end_of_rom, &cbfs_header))
189 		return;
190 
191 	start_of_rom = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);
192 
193 	file_cbfs_fill_cache(start_of_rom + cbfs_header.offset,
194 			     cbfs_header.rom_size, cbfs_header.align);
195 	if (file_cbfs_result == CBFS_SUCCESS)
196 		initialized = 1;
197 }
198 
199 const struct cbfs_header *file_cbfs_get_header(void)
200 {
201 	if (initialized) {
202 		file_cbfs_result = CBFS_SUCCESS;
203 		return &cbfs_header;
204 	} else {
205 		file_cbfs_result = CBFS_NOT_INITIALIZED;
206 		return NULL;
207 	}
208 }
209 
210 const struct cbfs_cachenode *file_cbfs_get_first(void)
211 {
212 	if (!initialized) {
213 		file_cbfs_result = CBFS_NOT_INITIALIZED;
214 		return NULL;
215 	} else {
216 		file_cbfs_result = CBFS_SUCCESS;
217 		return file_cache;
218 	}
219 }
220 
221 void file_cbfs_get_next(const struct cbfs_cachenode **file)
222 {
223 	if (!initialized) {
224 		file_cbfs_result = CBFS_NOT_INITIALIZED;
225 		file = NULL;
226 		return;
227 	}
228 
229 	if (*file)
230 		*file = (*file)->next;
231 	file_cbfs_result = CBFS_SUCCESS;
232 }
233 
234 const struct cbfs_cachenode *file_cbfs_find(const char *name)
235 {
236 	struct cbfs_cachenode *cache_node = file_cache;
237 
238 	if (!initialized) {
239 		file_cbfs_result = CBFS_NOT_INITIALIZED;
240 		return NULL;
241 	}
242 
243 	while (cache_node) {
244 		if (!strcmp(name, cache_node->name))
245 			break;
246 		cache_node = cache_node->next;
247 	}
248 	if (!cache_node)
249 		file_cbfs_result = CBFS_FILE_NOT_FOUND;
250 	else
251 		file_cbfs_result = CBFS_SUCCESS;
252 
253 	return cache_node;
254 }
255 
256 const struct cbfs_cachenode *file_cbfs_find_uncached(uintptr_t end_of_rom,
257 						     const char *name)
258 {
259 	u8 *start;
260 	u32 size;
261 	u32 align;
262 	static struct cbfs_cachenode node;
263 
264 	if (file_cbfs_load_header(end_of_rom, &cbfs_header))
265 		return NULL;
266 
267 	start = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);
268 	size = cbfs_header.rom_size;
269 	align = cbfs_header.align;
270 
271 	while (size >= align) {
272 		int result;
273 		u32 used;
274 
275 		result = file_cbfs_next_file(start, size, align, &node, &used);
276 
277 		if (result < 0)
278 			return NULL;
279 		else if (result == 0)
280 			break;
281 
282 		if (!strcmp(name, node.name))
283 			return &node;
284 
285 		size -= used;
286 		start += used;
287 	}
288 	file_cbfs_result = CBFS_FILE_NOT_FOUND;
289 	return NULL;
290 }
291 
292 const char *file_cbfs_name(const struct cbfs_cachenode *file)
293 {
294 	file_cbfs_result = CBFS_SUCCESS;
295 	return file->name;
296 }
297 
298 u32 file_cbfs_size(const struct cbfs_cachenode *file)
299 {
300 	file_cbfs_result = CBFS_SUCCESS;
301 	return file->data_length;
302 }
303 
304 u32 file_cbfs_type(const struct cbfs_cachenode *file)
305 {
306 	file_cbfs_result = CBFS_SUCCESS;
307 	return file->type;
308 }
309 
310 long file_cbfs_read(const struct cbfs_cachenode *file, void *buffer,
311 		    unsigned long maxsize)
312 {
313 	u32 size;
314 
315 	size = file->data_length;
316 	if (maxsize && size > maxsize)
317 		size = maxsize;
318 
319 	memcpy(buffer, file->data, size);
320 
321 	file_cbfs_result = CBFS_SUCCESS;
322 	return size;
323 }
324