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78c08247 WL |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | #define dev_fmt(fmt) "mtdoops-pstore: " fmt | |
4 | ||
5 | #include <linux/kernel.h> | |
6 | #include <linux/module.h> | |
7 | #include <linux/pstore_blk.h> | |
8 | #include <linux/mtd/mtd.h> | |
9 | #include <linux/bitops.h> | |
7999096f | 10 | #include <linux/slab.h> |
78c08247 WL |
11 | |
12 | static struct mtdpstore_context { | |
13 | int index; | |
14 | struct pstore_blk_config info; | |
15 | struct pstore_device_info dev; | |
16 | struct mtd_info *mtd; | |
17 | unsigned long *rmmap; /* removed bit map */ | |
18 | unsigned long *usedmap; /* used bit map */ | |
19 | /* | |
20 | * used for panic write | |
21 | * As there are no block_isbad for panic case, we should keep this | |
22 | * status before panic to ensure panic_write not failed. | |
23 | */ | |
24 | unsigned long *badmap; /* bad block bit map */ | |
25 | } oops_cxt; | |
26 | ||
27 | static int mtdpstore_block_isbad(struct mtdpstore_context *cxt, loff_t off) | |
28 | { | |
29 | int ret; | |
30 | struct mtd_info *mtd = cxt->mtd; | |
31 | u64 blknum; | |
32 | ||
33 | off = ALIGN_DOWN(off, mtd->erasesize); | |
34 | blknum = div_u64(off, mtd->erasesize); | |
35 | ||
36 | if (test_bit(blknum, cxt->badmap)) | |
37 | return true; | |
38 | ret = mtd_block_isbad(mtd, off); | |
39 | if (ret < 0) { | |
40 | dev_err(&mtd->dev, "mtd_block_isbad failed, aborting\n"); | |
41 | return ret; | |
42 | } else if (ret > 0) { | |
43 | set_bit(blknum, cxt->badmap); | |
44 | return true; | |
45 | } | |
46 | return false; | |
47 | } | |
48 | ||
49 | static inline int mtdpstore_panic_block_isbad(struct mtdpstore_context *cxt, | |
50 | loff_t off) | |
51 | { | |
52 | struct mtd_info *mtd = cxt->mtd; | |
53 | u64 blknum; | |
54 | ||
55 | off = ALIGN_DOWN(off, mtd->erasesize); | |
56 | blknum = div_u64(off, mtd->erasesize); | |
57 | return test_bit(blknum, cxt->badmap); | |
58 | } | |
59 | ||
60 | static inline void mtdpstore_mark_used(struct mtdpstore_context *cxt, | |
61 | loff_t off) | |
62 | { | |
63 | struct mtd_info *mtd = cxt->mtd; | |
64 | u64 zonenum = div_u64(off, cxt->info.kmsg_size); | |
65 | ||
66 | dev_dbg(&mtd->dev, "mark zone %llu used\n", zonenum); | |
67 | set_bit(zonenum, cxt->usedmap); | |
68 | } | |
69 | ||
70 | static inline void mtdpstore_mark_unused(struct mtdpstore_context *cxt, | |
71 | loff_t off) | |
72 | { | |
73 | struct mtd_info *mtd = cxt->mtd; | |
74 | u64 zonenum = div_u64(off, cxt->info.kmsg_size); | |
75 | ||
76 | dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); | |
77 | clear_bit(zonenum, cxt->usedmap); | |
78 | } | |
79 | ||
80 | static inline void mtdpstore_block_mark_unused(struct mtdpstore_context *cxt, | |
81 | loff_t off) | |
82 | { | |
83 | struct mtd_info *mtd = cxt->mtd; | |
84 | u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; | |
85 | u64 zonenum; | |
86 | ||
87 | off = ALIGN_DOWN(off, mtd->erasesize); | |
88 | zonenum = div_u64(off, cxt->info.kmsg_size); | |
89 | while (zonecnt > 0) { | |
90 | dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); | |
91 | clear_bit(zonenum, cxt->usedmap); | |
92 | zonenum++; | |
93 | zonecnt--; | |
94 | } | |
95 | } | |
96 | ||
97 | static inline int mtdpstore_is_used(struct mtdpstore_context *cxt, loff_t off) | |
98 | { | |
99 | u64 zonenum = div_u64(off, cxt->info.kmsg_size); | |
100 | u64 blknum = div_u64(off, cxt->mtd->erasesize); | |
101 | ||
102 | if (test_bit(blknum, cxt->badmap)) | |
103 | return true; | |
104 | return test_bit(zonenum, cxt->usedmap); | |
105 | } | |
106 | ||
107 | static int mtdpstore_block_is_used(struct mtdpstore_context *cxt, | |
108 | loff_t off) | |
109 | { | |
110 | struct mtd_info *mtd = cxt->mtd; | |
111 | u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; | |
112 | u64 zonenum; | |
113 | ||
114 | off = ALIGN_DOWN(off, mtd->erasesize); | |
115 | zonenum = div_u64(off, cxt->info.kmsg_size); | |
116 | while (zonecnt > 0) { | |
117 | if (test_bit(zonenum, cxt->usedmap)) | |
118 | return true; | |
119 | zonenum++; | |
120 | zonecnt--; | |
121 | } | |
122 | return false; | |
123 | } | |
124 | ||
125 | static int mtdpstore_is_empty(struct mtdpstore_context *cxt, char *buf, | |
126 | size_t size) | |
127 | { | |
128 | struct mtd_info *mtd = cxt->mtd; | |
129 | size_t sz; | |
130 | int i; | |
131 | ||
132 | sz = min_t(uint32_t, size, mtd->writesize / 4); | |
133 | for (i = 0; i < sz; i++) { | |
134 | if (buf[i] != (char)0xFF) | |
135 | return false; | |
136 | } | |
137 | return true; | |
138 | } | |
139 | ||
140 | static void mtdpstore_mark_removed(struct mtdpstore_context *cxt, loff_t off) | |
141 | { | |
142 | struct mtd_info *mtd = cxt->mtd; | |
143 | u64 zonenum = div_u64(off, cxt->info.kmsg_size); | |
144 | ||
145 | dev_dbg(&mtd->dev, "mark zone %llu removed\n", zonenum); | |
146 | set_bit(zonenum, cxt->rmmap); | |
147 | } | |
148 | ||
149 | static void mtdpstore_block_clear_removed(struct mtdpstore_context *cxt, | |
150 | loff_t off) | |
151 | { | |
152 | struct mtd_info *mtd = cxt->mtd; | |
153 | u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; | |
154 | u64 zonenum; | |
155 | ||
156 | off = ALIGN_DOWN(off, mtd->erasesize); | |
157 | zonenum = div_u64(off, cxt->info.kmsg_size); | |
158 | while (zonecnt > 0) { | |
159 | clear_bit(zonenum, cxt->rmmap); | |
160 | zonenum++; | |
161 | zonecnt--; | |
162 | } | |
163 | } | |
164 | ||
165 | static int mtdpstore_block_is_removed(struct mtdpstore_context *cxt, | |
166 | loff_t off) | |
167 | { | |
168 | struct mtd_info *mtd = cxt->mtd; | |
169 | u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; | |
170 | u64 zonenum; | |
171 | ||
172 | off = ALIGN_DOWN(off, mtd->erasesize); | |
173 | zonenum = div_u64(off, cxt->info.kmsg_size); | |
174 | while (zonecnt > 0) { | |
175 | if (test_bit(zonenum, cxt->rmmap)) | |
176 | return true; | |
177 | zonenum++; | |
178 | zonecnt--; | |
179 | } | |
180 | return false; | |
181 | } | |
182 | ||
183 | static int mtdpstore_erase_do(struct mtdpstore_context *cxt, loff_t off) | |
184 | { | |
185 | struct mtd_info *mtd = cxt->mtd; | |
186 | struct erase_info erase; | |
187 | int ret; | |
188 | ||
189 | off = ALIGN_DOWN(off, cxt->mtd->erasesize); | |
190 | dev_dbg(&mtd->dev, "try to erase off 0x%llx\n", off); | |
191 | erase.len = cxt->mtd->erasesize; | |
192 | erase.addr = off; | |
193 | ret = mtd_erase(cxt->mtd, &erase); | |
194 | if (!ret) | |
195 | mtdpstore_block_clear_removed(cxt, off); | |
196 | else | |
197 | dev_err(&mtd->dev, "erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", | |
198 | (unsigned long long)erase.addr, | |
199 | (unsigned long long)erase.len, cxt->info.device); | |
200 | return ret; | |
201 | } | |
202 | ||
203 | /* | |
204 | * called while removing file | |
205 | * | |
206 | * Avoiding over erasing, do erase block only when the whole block is unused. | |
207 | * If the block contains valid log, do erase lazily on flush_removed() when | |
208 | * unregister. | |
209 | */ | |
210 | static ssize_t mtdpstore_erase(size_t size, loff_t off) | |
211 | { | |
212 | struct mtdpstore_context *cxt = &oops_cxt; | |
213 | ||
214 | if (mtdpstore_block_isbad(cxt, off)) | |
215 | return -EIO; | |
216 | ||
217 | mtdpstore_mark_unused(cxt, off); | |
218 | ||
219 | /* If the block still has valid data, mtdpstore do erase lazily */ | |
220 | if (likely(mtdpstore_block_is_used(cxt, off))) { | |
221 | mtdpstore_mark_removed(cxt, off); | |
222 | return 0; | |
223 | } | |
224 | ||
225 | /* all zones are unused, erase it */ | |
226 | return mtdpstore_erase_do(cxt, off); | |
227 | } | |
228 | ||
229 | /* | |
230 | * What is security for mtdpstore? | |
231 | * As there is no erase for panic case, we should ensure at least one zone | |
232 | * is writable. Otherwise, panic write will fail. | |
233 | * If zone is used, write operation will return -ENOMSG, which means that | |
234 | * pstore/blk will try one by one until gets an empty zone. So, it is not | |
235 | * needed to ensure the next zone is empty, but at least one. | |
236 | */ | |
237 | static int mtdpstore_security(struct mtdpstore_context *cxt, loff_t off) | |
238 | { | |
239 | int ret = 0, i; | |
240 | struct mtd_info *mtd = cxt->mtd; | |
241 | u32 zonenum = (u32)div_u64(off, cxt->info.kmsg_size); | |
242 | u32 zonecnt = (u32)div_u64(cxt->mtd->size, cxt->info.kmsg_size); | |
243 | u32 blkcnt = (u32)div_u64(cxt->mtd->size, cxt->mtd->erasesize); | |
244 | u32 erasesize = cxt->mtd->erasesize; | |
245 | ||
246 | for (i = 0; i < zonecnt; i++) { | |
247 | u32 num = (zonenum + i) % zonecnt; | |
248 | ||
249 | /* found empty zone */ | |
250 | if (!test_bit(num, cxt->usedmap)) | |
251 | return 0; | |
252 | } | |
253 | ||
254 | /* If there is no any empty zone, we have no way but to do erase */ | |
255 | while (blkcnt--) { | |
256 | div64_u64_rem(off + erasesize, cxt->mtd->size, (u64 *)&off); | |
257 | ||
258 | if (mtdpstore_block_isbad(cxt, off)) | |
259 | continue; | |
260 | ||
261 | ret = mtdpstore_erase_do(cxt, off); | |
262 | if (!ret) { | |
263 | mtdpstore_block_mark_unused(cxt, off); | |
264 | break; | |
265 | } | |
266 | } | |
267 | ||
268 | if (ret) | |
269 | dev_err(&mtd->dev, "all blocks bad!\n"); | |
270 | dev_dbg(&mtd->dev, "end security\n"); | |
271 | return ret; | |
272 | } | |
273 | ||
274 | static ssize_t mtdpstore_write(const char *buf, size_t size, loff_t off) | |
275 | { | |
276 | struct mtdpstore_context *cxt = &oops_cxt; | |
277 | struct mtd_info *mtd = cxt->mtd; | |
278 | size_t retlen; | |
279 | int ret; | |
280 | ||
281 | if (mtdpstore_block_isbad(cxt, off)) | |
282 | return -ENOMSG; | |
283 | ||
284 | /* zone is used, please try next one */ | |
285 | if (mtdpstore_is_used(cxt, off)) | |
286 | return -ENOMSG; | |
287 | ||
288 | dev_dbg(&mtd->dev, "try to write off 0x%llx size %zu\n", off, size); | |
289 | ret = mtd_write(cxt->mtd, off, size, &retlen, (u_char *)buf); | |
290 | if (ret < 0 || retlen != size) { | |
291 | dev_err(&mtd->dev, "write failure at %lld (%zu of %zu written), err %d\n", | |
292 | off, retlen, size, ret); | |
293 | return -EIO; | |
294 | } | |
295 | mtdpstore_mark_used(cxt, off); | |
296 | ||
297 | mtdpstore_security(cxt, off); | |
298 | return retlen; | |
299 | } | |
300 | ||
301 | static inline bool mtdpstore_is_io_error(int ret) | |
302 | { | |
303 | return ret < 0 && !mtd_is_bitflip(ret) && !mtd_is_eccerr(ret); | |
304 | } | |
305 | ||
306 | /* | |
307 | * All zones will be read as pstore/blk will read zone one by one when do | |
308 | * recover. | |
309 | */ | |
310 | static ssize_t mtdpstore_read(char *buf, size_t size, loff_t off) | |
311 | { | |
312 | struct mtdpstore_context *cxt = &oops_cxt; | |
313 | struct mtd_info *mtd = cxt->mtd; | |
314 | size_t retlen, done; | |
315 | int ret; | |
316 | ||
317 | if (mtdpstore_block_isbad(cxt, off)) | |
318 | return -ENOMSG; | |
319 | ||
320 | dev_dbg(&mtd->dev, "try to read off 0x%llx size %zu\n", off, size); | |
321 | for (done = 0, retlen = 0; done < size; done += retlen) { | |
322 | retlen = 0; | |
323 | ||
324 | ret = mtd_read(cxt->mtd, off + done, size - done, &retlen, | |
325 | (u_char *)buf + done); | |
326 | if (mtdpstore_is_io_error(ret)) { | |
327 | dev_err(&mtd->dev, "read failure at %lld (%zu of %zu read), err %d\n", | |
328 | off + done, retlen, size - done, ret); | |
329 | /* the zone may be broken, try next one */ | |
330 | return -ENOMSG; | |
331 | } | |
332 | ||
333 | /* | |
334 | * ECC error. The impact on log data is so small. Maybe we can | |
335 | * still read it and try to understand. So mtdpstore just hands | |
336 | * over what it gets and user can judge whether the data is | |
337 | * valid or not. | |
338 | */ | |
339 | if (mtd_is_eccerr(ret)) { | |
340 | dev_err(&mtd->dev, "ecc error at %lld (%zu of %zu read), err %d\n", | |
341 | off + done, retlen, size - done, ret); | |
342 | /* driver may not set retlen when ecc error */ | |
343 | retlen = retlen == 0 ? size - done : retlen; | |
344 | } | |
345 | } | |
346 | ||
347 | if (mtdpstore_is_empty(cxt, buf, size)) | |
348 | mtdpstore_mark_unused(cxt, off); | |
349 | else | |
350 | mtdpstore_mark_used(cxt, off); | |
351 | ||
352 | mtdpstore_security(cxt, off); | |
353 | return retlen; | |
354 | } | |
355 | ||
356 | static ssize_t mtdpstore_panic_write(const char *buf, size_t size, loff_t off) | |
357 | { | |
358 | struct mtdpstore_context *cxt = &oops_cxt; | |
359 | struct mtd_info *mtd = cxt->mtd; | |
360 | size_t retlen; | |
361 | int ret; | |
362 | ||
363 | if (mtdpstore_panic_block_isbad(cxt, off)) | |
364 | return -ENOMSG; | |
365 | ||
366 | /* zone is used, please try next one */ | |
367 | if (mtdpstore_is_used(cxt, off)) | |
368 | return -ENOMSG; | |
369 | ||
370 | ret = mtd_panic_write(cxt->mtd, off, size, &retlen, (u_char *)buf); | |
371 | if (ret < 0 || size != retlen) { | |
372 | dev_err(&mtd->dev, "panic write failure at %lld (%zu of %zu read), err %d\n", | |
373 | off, retlen, size, ret); | |
374 | return -EIO; | |
375 | } | |
376 | mtdpstore_mark_used(cxt, off); | |
377 | ||
378 | return retlen; | |
379 | } | |
380 | ||
381 | static void mtdpstore_notify_add(struct mtd_info *mtd) | |
382 | { | |
383 | int ret; | |
384 | struct mtdpstore_context *cxt = &oops_cxt; | |
385 | struct pstore_blk_config *info = &cxt->info; | |
386 | unsigned long longcnt; | |
387 | ||
388 | if (!strcmp(mtd->name, info->device)) | |
389 | cxt->index = mtd->index; | |
390 | ||
391 | if (mtd->index != cxt->index || cxt->index < 0) | |
392 | return; | |
393 | ||
394 | dev_dbg(&mtd->dev, "found matching MTD device %s\n", mtd->name); | |
395 | ||
396 | if (mtd->size < info->kmsg_size * 2) { | |
397 | dev_err(&mtd->dev, "MTD partition %d not big enough\n", | |
398 | mtd->index); | |
399 | return; | |
400 | } | |
401 | /* | |
402 | * kmsg_size must be aligned to 4096 Bytes, which is limited by | |
403 | * psblk. The default value of kmsg_size is 64KB. If kmsg_size | |
404 | * is larger than erasesize, some errors will occur since mtdpsotre | |
405 | * is designed on it. | |
406 | */ | |
407 | if (mtd->erasesize < info->kmsg_size) { | |
408 | dev_err(&mtd->dev, "eraseblock size of MTD partition %d too small\n", | |
409 | mtd->index); | |
410 | return; | |
411 | } | |
412 | if (unlikely(info->kmsg_size % mtd->writesize)) { | |
413 | dev_err(&mtd->dev, "record size %lu KB must align to write size %d KB\n", | |
414 | info->kmsg_size / 1024, | |
415 | mtd->writesize / 1024); | |
416 | return; | |
417 | } | |
418 | ||
419 | longcnt = BITS_TO_LONGS(div_u64(mtd->size, info->kmsg_size)); | |
420 | cxt->rmmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); | |
421 | cxt->usedmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); | |
422 | ||
423 | longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize)); | |
424 | cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); | |
425 | ||
426 | cxt->dev.total_size = mtd->size; | |
427 | /* just support dmesg right now */ | |
428 | cxt->dev.flags = PSTORE_FLAGS_DMESG; | |
429 | cxt->dev.read = mtdpstore_read; | |
430 | cxt->dev.write = mtdpstore_write; | |
431 | cxt->dev.erase = mtdpstore_erase; | |
432 | cxt->dev.panic_write = mtdpstore_panic_write; | |
433 | ||
434 | ret = register_pstore_device(&cxt->dev); | |
435 | if (ret) { | |
436 | dev_err(&mtd->dev, "mtd%d register to psblk failed\n", | |
437 | mtd->index); | |
438 | return; | |
439 | } | |
440 | cxt->mtd = mtd; | |
441 | dev_info(&mtd->dev, "Attached to MTD device %d\n", mtd->index); | |
442 | } | |
443 | ||
444 | static int mtdpstore_flush_removed_do(struct mtdpstore_context *cxt, | |
445 | loff_t off, size_t size) | |
446 | { | |
447 | struct mtd_info *mtd = cxt->mtd; | |
448 | u_char *buf; | |
449 | int ret; | |
450 | size_t retlen; | |
451 | struct erase_info erase; | |
452 | ||
453 | buf = kmalloc(mtd->erasesize, GFP_KERNEL); | |
454 | if (!buf) | |
455 | return -ENOMEM; | |
456 | ||
457 | /* 1st. read to cache */ | |
458 | ret = mtd_read(mtd, off, mtd->erasesize, &retlen, buf); | |
459 | if (mtdpstore_is_io_error(ret)) | |
460 | goto free; | |
461 | ||
462 | /* 2nd. erase block */ | |
463 | erase.len = mtd->erasesize; | |
464 | erase.addr = off; | |
465 | ret = mtd_erase(mtd, &erase); | |
466 | if (ret) | |
467 | goto free; | |
468 | ||
469 | /* 3rd. write back */ | |
470 | while (size) { | |
471 | unsigned int zonesize = cxt->info.kmsg_size; | |
472 | ||
473 | /* there is valid data on block, write back */ | |
474 | if (mtdpstore_is_used(cxt, off)) { | |
475 | ret = mtd_write(mtd, off, zonesize, &retlen, buf); | |
476 | if (ret) | |
477 | dev_err(&mtd->dev, "write failure at %lld (%zu of %u written), err %d\n", | |
478 | off, retlen, zonesize, ret); | |
479 | } | |
480 | ||
481 | off += zonesize; | |
482 | size -= min_t(unsigned int, zonesize, size); | |
483 | } | |
484 | ||
485 | free: | |
486 | kfree(buf); | |
487 | return ret; | |
488 | } | |
489 | ||
490 | /* | |
491 | * What does mtdpstore_flush_removed() do? | |
492 | * When user remove any log file on pstore filesystem, mtdpstore should do | |
493 | * something to ensure log file removed. If the whole block is no longer used, | |
494 | * it's nice to erase the block. However if the block still contains valid log, | |
495 | * what mtdpstore can do is to erase and write the valid log back. | |
496 | */ | |
497 | static int mtdpstore_flush_removed(struct mtdpstore_context *cxt) | |
498 | { | |
499 | struct mtd_info *mtd = cxt->mtd; | |
500 | int ret; | |
501 | loff_t off; | |
502 | u32 blkcnt = (u32)div_u64(mtd->size, mtd->erasesize); | |
503 | ||
504 | for (off = 0; blkcnt > 0; blkcnt--, off += mtd->erasesize) { | |
505 | ret = mtdpstore_block_isbad(cxt, off); | |
506 | if (ret) | |
507 | continue; | |
508 | ||
509 | ret = mtdpstore_block_is_removed(cxt, off); | |
510 | if (!ret) | |
511 | continue; | |
512 | ||
513 | ret = mtdpstore_flush_removed_do(cxt, off, mtd->erasesize); | |
514 | if (ret) | |
515 | return ret; | |
516 | } | |
517 | return 0; | |
518 | } | |
519 | ||
520 | static void mtdpstore_notify_remove(struct mtd_info *mtd) | |
521 | { | |
522 | struct mtdpstore_context *cxt = &oops_cxt; | |
523 | ||
524 | if (mtd->index != cxt->index || cxt->index < 0) | |
525 | return; | |
526 | ||
527 | mtdpstore_flush_removed(cxt); | |
528 | ||
529 | unregister_pstore_device(&cxt->dev); | |
530 | kfree(cxt->badmap); | |
531 | kfree(cxt->usedmap); | |
532 | kfree(cxt->rmmap); | |
533 | cxt->mtd = NULL; | |
534 | cxt->index = -1; | |
535 | } | |
536 | ||
537 | static struct mtd_notifier mtdpstore_notifier = { | |
538 | .add = mtdpstore_notify_add, | |
539 | .remove = mtdpstore_notify_remove, | |
540 | }; | |
541 | ||
542 | static int __init mtdpstore_init(void) | |
543 | { | |
544 | int ret; | |
545 | struct mtdpstore_context *cxt = &oops_cxt; | |
546 | struct pstore_blk_config *info = &cxt->info; | |
547 | ||
548 | ret = pstore_blk_get_config(info); | |
549 | if (unlikely(ret)) | |
550 | return ret; | |
551 | ||
552 | if (strlen(info->device) == 0) { | |
553 | pr_err("mtd device must be supplied (device name is empty)\n"); | |
554 | return -EINVAL; | |
555 | } | |
556 | if (!info->kmsg_size) { | |
557 | pr_err("no backend enabled (kmsg_size is 0)\n"); | |
558 | return -EINVAL; | |
559 | } | |
560 | ||
561 | /* Setup the MTD device to use */ | |
562 | ret = kstrtoint((char *)info->device, 0, &cxt->index); | |
563 | if (ret) | |
564 | cxt->index = -1; | |
565 | ||
566 | register_mtd_user(&mtdpstore_notifier); | |
567 | return 0; | |
568 | } | |
569 | module_init(mtdpstore_init); | |
570 | ||
571 | static void __exit mtdpstore_exit(void) | |
572 | { | |
573 | unregister_mtd_user(&mtdpstore_notifier); | |
574 | } | |
575 | module_exit(mtdpstore_exit); | |
576 | ||
577 | MODULE_LICENSE("GPL"); | |
578 | MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>"); | |
579 | MODULE_DESCRIPTION("MTD backend for pstore/blk"); |