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