1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /*====================================================================== |
3 | |
4 | drivers/mtd/afs.c: ARM Flash Layout/Partitioning |
5 | |
6 | Copyright © 2000 ARM Limited |
7 | Copyright (C) 2019 Linus Walleij |
8 | |
9 | |
10 | This is access code for flashes using ARM's flash partitioning |
11 | standards. |
12 | |
13 | ======================================================================*/ |
14 | |
15 | #include <linux/module.h> |
16 | #include <linux/types.h> |
17 | #include <linux/kernel.h> |
18 | #include <linux/slab.h> |
19 | #include <linux/string.h> |
20 | #include <linux/init.h> |
21 | |
22 | #include <linux/mtd/mtd.h> |
23 | #include <linux/mtd/map.h> |
24 | #include <linux/mtd/partitions.h> |
25 | |
26 | #define 0xA0FFFF9F |
27 | #define 0x464C5348 /* "FLSH" */ |
28 | #define 0x464F4F54 /* "FOOT" */ |
29 | |
30 | struct { |
31 | u32 ; /* Address of first word of ImageFooter */ |
32 | u32 ; /* Start of area reserved by this footer */ |
33 | u32 ; /* 'Magic' number proves it's a footer */ |
34 | u32 ; /* Area type: ARM Image, SIB, customer */ |
35 | u32 ; /* Just this structure */ |
36 | }; |
37 | |
38 | struct image_info_v1 { |
39 | u32 bootFlags; /* Boot flags, compression etc. */ |
40 | u32 imageNumber; /* Unique number, selects for boot etc. */ |
41 | u32 loadAddress; /* Address program should be loaded to */ |
42 | u32 length; /* Actual size of image */ |
43 | u32 address; /* Image is executed from here */ |
44 | char name[16]; /* Null terminated */ |
45 | u32 ; /* Flash Address of any stripped header */ |
46 | u32 ; /* Length of header in memory */ |
47 | u32 ; /* AIF, RLF, s-record etc. */ |
48 | u32 checksum; /* Image checksum (inc. this struct) */ |
49 | }; |
50 | |
51 | static u32 word_sum(void *words, int num) |
52 | { |
53 | u32 *p = words; |
54 | u32 sum = 0; |
55 | |
56 | while (num--) |
57 | sum += *p++; |
58 | |
59 | return sum; |
60 | } |
61 | |
62 | static u32 word_sum_v2(u32 *p, u32 num) |
63 | { |
64 | u32 sum = 0; |
65 | int i; |
66 | |
67 | for (i = 0; i < num; i++) { |
68 | u32 val; |
69 | |
70 | val = p[i]; |
71 | if (val > ~sum) |
72 | sum++; |
73 | sum += val; |
74 | } |
75 | return ~sum; |
76 | } |
77 | |
78 | static bool afs_is_v1(struct mtd_info *mtd, u_int off) |
79 | { |
80 | /* The magic is 12 bytes from the end of the erase block */ |
81 | u_int ptr = off + mtd->erasesize - 12; |
82 | u32 magic; |
83 | size_t sz; |
84 | int ret; |
85 | |
86 | ret = mtd_read(mtd, from: ptr, len: 4, retlen: &sz, buf: (u_char *)&magic); |
87 | if (ret < 0) { |
88 | printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n" , |
89 | ptr, ret); |
90 | return false; |
91 | } |
92 | if (ret >= 0 && sz != 4) |
93 | return false; |
94 | |
95 | return (magic == AFSV1_FOOTER_MAGIC); |
96 | } |
97 | |
98 | static bool afs_is_v2(struct mtd_info *mtd, u_int off) |
99 | { |
100 | /* The magic is the 8 last bytes of the erase block */ |
101 | u_int ptr = off + mtd->erasesize - 8; |
102 | u32 [2]; |
103 | size_t sz; |
104 | int ret; |
105 | |
106 | ret = mtd_read(mtd, from: ptr, len: 8, retlen: &sz, buf: (u_char *)foot); |
107 | if (ret < 0) { |
108 | printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n" , |
109 | ptr, ret); |
110 | return false; |
111 | } |
112 | if (ret >= 0 && sz != 8) |
113 | return false; |
114 | |
115 | return (foot[0] == AFSV2_FOOTER_MAGIC1 && |
116 | foot[1] == AFSV2_FOOTER_MAGIC2); |
117 | } |
118 | |
119 | static int afs_parse_v1_partition(struct mtd_info *mtd, |
120 | u_int off, struct mtd_partition *part) |
121 | { |
122 | struct footer_v1 fs; |
123 | struct image_info_v1 iis; |
124 | u_int mask; |
125 | /* |
126 | * Static checks cannot see that we bail out if we have an error |
127 | * reading the footer. |
128 | */ |
129 | u_int iis_ptr; |
130 | u_int img_ptr; |
131 | u_int ptr; |
132 | size_t sz; |
133 | int ret; |
134 | int i; |
135 | |
136 | /* |
137 | * This is the address mask; we use this to mask off out of |
138 | * range address bits. |
139 | */ |
140 | mask = mtd->size - 1; |
141 | |
142 | ptr = off + mtd->erasesize - sizeof(fs); |
143 | ret = mtd_read(mtd, from: ptr, len: sizeof(fs), retlen: &sz, buf: (u_char *)&fs); |
144 | if (ret >= 0 && sz != sizeof(fs)) |
145 | ret = -EINVAL; |
146 | if (ret < 0) { |
147 | printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n" , |
148 | ptr, ret); |
149 | return ret; |
150 | } |
151 | /* |
152 | * Check the checksum. |
153 | */ |
154 | if (word_sum(words: &fs, num: sizeof(fs) / sizeof(u32)) != 0xffffffff) |
155 | return -EINVAL; |
156 | |
157 | /* |
158 | * Hide the SIB (System Information Block) |
159 | */ |
160 | if (fs.type == 2) |
161 | return 0; |
162 | |
163 | iis_ptr = fs.image_info_base & mask; |
164 | img_ptr = fs.image_start & mask; |
165 | |
166 | /* |
167 | * Check the image info base. This can not |
168 | * be located after the footer structure. |
169 | */ |
170 | if (iis_ptr >= ptr) |
171 | return 0; |
172 | |
173 | /* |
174 | * Check the start of this image. The image |
175 | * data can not be located after this block. |
176 | */ |
177 | if (img_ptr > off) |
178 | return 0; |
179 | |
180 | /* Read the image info block */ |
181 | memset(&iis, 0, sizeof(iis)); |
182 | ret = mtd_read(mtd, from: iis_ptr, len: sizeof(iis), retlen: &sz, buf: (u_char *)&iis); |
183 | if (ret < 0) { |
184 | printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n" , |
185 | iis_ptr, ret); |
186 | return -EINVAL; |
187 | } |
188 | |
189 | if (sz != sizeof(iis)) |
190 | return -EINVAL; |
191 | |
192 | /* |
193 | * Validate the name - it must be NUL terminated. |
194 | */ |
195 | for (i = 0; i < sizeof(iis.name); i++) |
196 | if (iis.name[i] == '\0') |
197 | break; |
198 | if (i > sizeof(iis.name)) |
199 | return -EINVAL; |
200 | |
201 | part->name = kstrdup(s: iis.name, GFP_KERNEL); |
202 | if (!part->name) |
203 | return -ENOMEM; |
204 | |
205 | part->size = (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1); |
206 | part->offset = img_ptr; |
207 | part->mask_flags = 0; |
208 | |
209 | printk(" mtd: at 0x%08x, %5lluKiB, %8u, %s\n" , |
210 | img_ptr, part->size / 1024, |
211 | iis.imageNumber, part->name); |
212 | |
213 | return 0; |
214 | } |
215 | |
216 | static int afs_parse_v2_partition(struct mtd_info *mtd, |
217 | u_int off, struct mtd_partition *part) |
218 | { |
219 | u_int ptr; |
220 | u32 [12]; |
221 | u32 imginfo[36]; |
222 | char *name; |
223 | u32 version; |
224 | u32 entrypoint; |
225 | u32 attributes; |
226 | u32 region_count; |
227 | u32 block_start; |
228 | u32 block_end; |
229 | u32 crc; |
230 | size_t sz; |
231 | int ret; |
232 | int i; |
233 | int pad = 0; |
234 | |
235 | pr_debug("Parsing v2 partition @%08x-%08x\n" , |
236 | off, off + mtd->erasesize); |
237 | |
238 | /* First read the footer */ |
239 | ptr = off + mtd->erasesize - sizeof(footer); |
240 | ret = mtd_read(mtd, from: ptr, len: sizeof(footer), retlen: &sz, buf: (u_char *)footer); |
241 | if ((ret < 0) || (ret >= 0 && sz != sizeof(footer))) { |
242 | pr_err("AFS: mtd read failed at 0x%x: %d\n" , |
243 | ptr, ret); |
244 | return -EIO; |
245 | } |
246 | name = (char *) &footer[0]; |
247 | version = footer[9]; |
248 | ptr = off + mtd->erasesize - sizeof(footer) - footer[8]; |
249 | |
250 | pr_debug("found image \"%s\", version %08x, info @%08x\n" , |
251 | name, version, ptr); |
252 | |
253 | /* Then read the image information */ |
254 | ret = mtd_read(mtd, from: ptr, len: sizeof(imginfo), retlen: &sz, buf: (u_char *)imginfo); |
255 | if ((ret < 0) || (ret >= 0 && sz != sizeof(imginfo))) { |
256 | pr_err("AFS: mtd read failed at 0x%x: %d\n" , |
257 | ptr, ret); |
258 | return -EIO; |
259 | } |
260 | |
261 | /* 32bit platforms have 4 bytes padding */ |
262 | crc = word_sum_v2(p: &imginfo[1], num: 34); |
263 | if (!crc) { |
264 | pr_debug("Padding 1 word (4 bytes)\n" ); |
265 | pad = 1; |
266 | } else { |
267 | /* 64bit platforms have 8 bytes padding */ |
268 | crc = word_sum_v2(p: &imginfo[2], num: 34); |
269 | if (!crc) { |
270 | pr_debug("Padding 2 words (8 bytes)\n" ); |
271 | pad = 2; |
272 | } |
273 | } |
274 | if (crc) { |
275 | pr_err("AFS: bad checksum on v2 image info: %08x\n" , crc); |
276 | return -EINVAL; |
277 | } |
278 | entrypoint = imginfo[pad]; |
279 | attributes = imginfo[pad+1]; |
280 | region_count = imginfo[pad+2]; |
281 | block_start = imginfo[20]; |
282 | block_end = imginfo[21]; |
283 | |
284 | pr_debug("image entry=%08x, attr=%08x, regions=%08x, " |
285 | "bs=%08x, be=%08x\n" , |
286 | entrypoint, attributes, region_count, |
287 | block_start, block_end); |
288 | |
289 | for (i = 0; i < region_count; i++) { |
290 | u32 region_load_addr = imginfo[pad + 3 + i*4]; |
291 | u32 region_size = imginfo[pad + 4 + i*4]; |
292 | u32 region_offset = imginfo[pad + 5 + i*4]; |
293 | u32 region_start; |
294 | u32 region_end; |
295 | |
296 | pr_debug(" region %d: address: %08x, size: %08x, " |
297 | "offset: %08x\n" , |
298 | i, |
299 | region_load_addr, |
300 | region_size, |
301 | region_offset); |
302 | |
303 | region_start = off + region_offset; |
304 | region_end = region_start + region_size; |
305 | /* Align partition to end of erase block */ |
306 | region_end += (mtd->erasesize - 1); |
307 | region_end &= ~(mtd->erasesize -1); |
308 | pr_debug(" partition start = %08x, partition end = %08x\n" , |
309 | region_start, region_end); |
310 | |
311 | /* Create one partition per region */ |
312 | part->name = kstrdup(s: name, GFP_KERNEL); |
313 | if (!part->name) |
314 | return -ENOMEM; |
315 | part->offset = region_start; |
316 | part->size = region_end - region_start; |
317 | part->mask_flags = 0; |
318 | } |
319 | |
320 | return 0; |
321 | } |
322 | |
323 | static int parse_afs_partitions(struct mtd_info *mtd, |
324 | const struct mtd_partition **pparts, |
325 | struct mtd_part_parser_data *data) |
326 | { |
327 | struct mtd_partition *parts; |
328 | u_int off, sz; |
329 | int ret = 0; |
330 | int i; |
331 | |
332 | /* Count the partitions by looping over all erase blocks */ |
333 | for (i = off = sz = 0; off < mtd->size; off += mtd->erasesize) { |
334 | if (afs_is_v1(mtd, off)) { |
335 | sz += sizeof(struct mtd_partition); |
336 | i += 1; |
337 | } |
338 | if (afs_is_v2(mtd, off)) { |
339 | sz += sizeof(struct mtd_partition); |
340 | i += 1; |
341 | } |
342 | } |
343 | |
344 | if (!i) |
345 | return 0; |
346 | |
347 | parts = kzalloc(size: sz, GFP_KERNEL); |
348 | if (!parts) |
349 | return -ENOMEM; |
350 | |
351 | /* |
352 | * Identify the partitions |
353 | */ |
354 | for (i = off = 0; off < mtd->size; off += mtd->erasesize) { |
355 | if (afs_is_v1(mtd, off)) { |
356 | ret = afs_parse_v1_partition(mtd, off, part: &parts[i]); |
357 | if (ret) |
358 | goto out_free_parts; |
359 | i++; |
360 | } |
361 | if (afs_is_v2(mtd, off)) { |
362 | ret = afs_parse_v2_partition(mtd, off, part: &parts[i]); |
363 | if (ret) |
364 | goto out_free_parts; |
365 | i++; |
366 | } |
367 | } |
368 | |
369 | *pparts = parts; |
370 | return i; |
371 | |
372 | out_free_parts: |
373 | while (--i >= 0) |
374 | kfree(objp: parts[i].name); |
375 | kfree(objp: parts); |
376 | *pparts = NULL; |
377 | return ret; |
378 | } |
379 | |
380 | static const struct of_device_id mtd_parser_afs_of_match_table[] = { |
381 | { .compatible = "arm,arm-firmware-suite" }, |
382 | {}, |
383 | }; |
384 | MODULE_DEVICE_TABLE(of, mtd_parser_afs_of_match_table); |
385 | |
386 | static struct mtd_part_parser afs_parser = { |
387 | .parse_fn = parse_afs_partitions, |
388 | .name = "afs" , |
389 | .of_match_table = mtd_parser_afs_of_match_table, |
390 | }; |
391 | module_mtd_part_parser(afs_parser); |
392 | |
393 | MODULE_AUTHOR("ARM Ltd" ); |
394 | MODULE_DESCRIPTION("ARM Firmware Suite partition parser" ); |
395 | MODULE_LICENSE("GPL" ); |
396 | |