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Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * block2mtd.c - create an mtd from a block device |
3 | * | |
4 | * Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk> | |
2b54aaef | 5 | * Copyright (C) 2004-2006 Joern Engel <joern@wh.fh-wedel.de> |
1da177e4 LT |
6 | * |
7 | * Licence: GPL | |
8 | */ | |
a1c06609 JP |
9 | |
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
11 | ||
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/fs.h> | |
14 | #include <linux/blkdev.h> | |
15 | #include <linux/bio.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/list.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/mtd/mtd.h> | |
48b19268 | 20 | #include <linux/mutex.h> |
c4e7fb31 | 21 | #include <linux/mount.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
f83c3838 | 23 | #include <linux/major.h> |
1da177e4 | 24 | |
1da177e4 LT |
25 | /* Info for the block device */ |
26 | struct block2mtd_dev { | |
27 | struct list_head list; | |
28 | struct block_device *blkdev; | |
29 | struct mtd_info mtd; | |
48b19268 | 30 | struct mutex write_mutex; |
1da177e4 LT |
31 | }; |
32 | ||
33 | ||
34 | /* Static info about the MTD, used in cleanup_module */ | |
35 | static LIST_HEAD(blkmtd_device_list); | |
36 | ||
37 | ||
6fe6900e | 38 | static struct page *page_read(struct address_space *mapping, int index) |
1da177e4 | 39 | { |
6fe6900e | 40 | return read_mapping_page(mapping, index, NULL); |
1da177e4 LT |
41 | } |
42 | ||
1da177e4 LT |
43 | /* erase a specified part of the device */ |
44 | static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len) | |
45 | { | |
46 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
47 | struct page *page; | |
48 | int index = to >> PAGE_SHIFT; // page index | |
49 | int pages = len >> PAGE_SHIFT; | |
50 | u_long *p; | |
51 | u_long *max; | |
52 | ||
53 | while (pages) { | |
21d31f1f | 54 | page = page_read(mapping, index); |
1da177e4 LT |
55 | if (IS_ERR(page)) |
56 | return PTR_ERR(page); | |
57 | ||
0ffb74cc JE |
58 | max = page_address(page) + PAGE_SIZE; |
59 | for (p=page_address(page); p<max; p++) | |
1da177e4 LT |
60 | if (*p != -1UL) { |
61 | lock_page(page); | |
62 | memset(page_address(page), 0xff, PAGE_SIZE); | |
63 | set_page_dirty(page); | |
64 | unlock_page(page); | |
031da73f | 65 | balance_dirty_pages_ratelimited(mapping); |
1da177e4 LT |
66 | break; |
67 | } | |
68 | ||
69 | page_cache_release(page); | |
70 | pages--; | |
71 | index++; | |
72 | } | |
73 | return 0; | |
74 | } | |
75 | static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr) | |
76 | { | |
77 | struct block2mtd_dev *dev = mtd->priv; | |
78 | size_t from = instr->addr; | |
79 | size_t len = instr->len; | |
80 | int err; | |
81 | ||
82 | instr->state = MTD_ERASING; | |
48b19268 | 83 | mutex_lock(&dev->write_mutex); |
1da177e4 | 84 | err = _block2mtd_erase(dev, from, len); |
48b19268 | 85 | mutex_unlock(&dev->write_mutex); |
1da177e4 | 86 | if (err) { |
a1c06609 | 87 | pr_err("erase failed err = %d\n", err); |
1da177e4 LT |
88 | instr->state = MTD_ERASE_FAILED; |
89 | } else | |
90 | instr->state = MTD_ERASE_DONE; | |
91 | ||
1da177e4 LT |
92 | mtd_erase_callback(instr); |
93 | return err; | |
94 | } | |
95 | ||
96 | ||
97 | static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len, | |
98 | size_t *retlen, u_char *buf) | |
99 | { | |
100 | struct block2mtd_dev *dev = mtd->priv; | |
101 | struct page *page; | |
102 | int index = from >> PAGE_SHIFT; | |
711c11b7 | 103 | int offset = from & (PAGE_SIZE-1); |
1da177e4 LT |
104 | int cpylen; |
105 | ||
1da177e4 LT |
106 | while (len) { |
107 | if ((offset + len) > PAGE_SIZE) | |
108 | cpylen = PAGE_SIZE - offset; // multiple pages | |
109 | else | |
110 | cpylen = len; // this page | |
111 | len = len - cpylen; | |
112 | ||
21d31f1f | 113 | page = page_read(dev->blkdev->bd_inode->i_mapping, index); |
1da177e4 LT |
114 | if (IS_ERR(page)) |
115 | return PTR_ERR(page); | |
116 | ||
117 | memcpy(buf, page_address(page) + offset, cpylen); | |
118 | page_cache_release(page); | |
119 | ||
120 | if (retlen) | |
121 | *retlen += cpylen; | |
122 | buf += cpylen; | |
123 | offset = 0; | |
124 | index++; | |
125 | } | |
126 | return 0; | |
127 | } | |
128 | ||
129 | ||
130 | /* write data to the underlying device */ | |
131 | static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf, | |
132 | loff_t to, size_t len, size_t *retlen) | |
133 | { | |
134 | struct page *page; | |
135 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
136 | int index = to >> PAGE_SHIFT; // page index | |
137 | int offset = to & ~PAGE_MASK; // page offset | |
138 | int cpylen; | |
139 | ||
1da177e4 | 140 | while (len) { |
e5580fbe | 141 | if ((offset+len) > PAGE_SIZE) |
1da177e4 LT |
142 | cpylen = PAGE_SIZE - offset; // multiple pages |
143 | else | |
144 | cpylen = len; // this page | |
145 | len = len - cpylen; | |
146 | ||
21d31f1f | 147 | page = page_read(mapping, index); |
1da177e4 LT |
148 | if (IS_ERR(page)) |
149 | return PTR_ERR(page); | |
150 | ||
151 | if (memcmp(page_address(page)+offset, buf, cpylen)) { | |
152 | lock_page(page); | |
153 | memcpy(page_address(page) + offset, buf, cpylen); | |
154 | set_page_dirty(page); | |
155 | unlock_page(page); | |
031da73f | 156 | balance_dirty_pages_ratelimited(mapping); |
1da177e4 LT |
157 | } |
158 | page_cache_release(page); | |
159 | ||
160 | if (retlen) | |
161 | *retlen += cpylen; | |
162 | ||
163 | buf += cpylen; | |
164 | offset = 0; | |
165 | index++; | |
166 | } | |
167 | return 0; | |
168 | } | |
c4e7fb31 VH |
169 | |
170 | ||
1da177e4 LT |
171 | static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len, |
172 | size_t *retlen, const u_char *buf) | |
173 | { | |
174 | struct block2mtd_dev *dev = mtd->priv; | |
175 | int err; | |
176 | ||
48b19268 | 177 | mutex_lock(&dev->write_mutex); |
1da177e4 | 178 | err = _block2mtd_write(dev, buf, to, len, retlen); |
48b19268 | 179 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
180 | if (err > 0) |
181 | err = 0; | |
182 | return err; | |
183 | } | |
184 | ||
185 | ||
186 | /* sync the device - wait until the write queue is empty */ | |
187 | static void block2mtd_sync(struct mtd_info *mtd) | |
188 | { | |
189 | struct block2mtd_dev *dev = mtd->priv; | |
190 | sync_blockdev(dev->blkdev); | |
191 | return; | |
192 | } | |
193 | ||
194 | ||
195 | static void block2mtd_free_device(struct block2mtd_dev *dev) | |
196 | { | |
197 | if (!dev) | |
198 | return; | |
199 | ||
200 | kfree(dev->mtd.name); | |
201 | ||
202 | if (dev->blkdev) { | |
fc0ecff6 AM |
203 | invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, |
204 | 0, -1); | |
e525fd89 | 205 | blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
1da177e4 LT |
206 | } |
207 | ||
208 | kfree(dev); | |
209 | } | |
210 | ||
211 | ||
212 | /* FIXME: ensure that mtd->size % erase_size == 0 */ | |
213 | static struct block2mtd_dev *add_device(char *devname, int erase_size) | |
214 | { | |
e525fd89 | 215 | const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; |
1da177e4 LT |
216 | struct block_device *bdev; |
217 | struct block2mtd_dev *dev; | |
eadcf0d7 | 218 | char *name; |
1da177e4 LT |
219 | |
220 | if (!devname) | |
221 | return NULL; | |
222 | ||
95b93a0c | 223 | dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL); |
1da177e4 LT |
224 | if (!dev) |
225 | return NULL; | |
1da177e4 LT |
226 | |
227 | /* Get a handle on the device */ | |
d4d77629 | 228 | bdev = blkdev_get_by_path(devname, mode, dev); |
c4e7fb31 VH |
229 | #ifndef MODULE |
230 | if (IS_ERR(bdev)) { | |
231 | ||
232 | /* We might not have rootfs mounted at this point. Try | |
233 | to resolve the device name by other means. */ | |
234 | ||
8870530a | 235 | dev_t devt = name_to_dev_t(devname); |
e525fd89 | 236 | if (devt) |
d4d77629 | 237 | bdev = blkdev_get_by_dev(devt, mode, dev); |
c4e7fb31 VH |
238 | } |
239 | #endif | |
240 | ||
1da177e4 | 241 | if (IS_ERR(bdev)) { |
a1c06609 | 242 | pr_err("error: cannot open device %s\n", devname); |
1da177e4 LT |
243 | goto devinit_err; |
244 | } | |
245 | dev->blkdev = bdev; | |
246 | ||
247 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
a1c06609 | 248 | pr_err("attempting to use an MTD device as a block device\n"); |
1da177e4 LT |
249 | goto devinit_err; |
250 | } | |
251 | ||
48b19268 | 252 | mutex_init(&dev->write_mutex); |
1da177e4 LT |
253 | |
254 | /* Setup the MTD structure */ | |
255 | /* make the name contain the block device in */ | |
4d682420 | 256 | name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname); |
eadcf0d7 | 257 | if (!name) |
1da177e4 LT |
258 | goto devinit_err; |
259 | ||
eadcf0d7 | 260 | dev->mtd.name = name; |
1da177e4 LT |
261 | |
262 | dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK; | |
263 | dev->mtd.erasesize = erase_size; | |
17ffc7ba | 264 | dev->mtd.writesize = 1; |
b6043874 | 265 | dev->mtd.writebufsize = PAGE_SIZE; |
21c8db9e | 266 | dev->mtd.type = MTD_RAM; |
1da177e4 | 267 | dev->mtd.flags = MTD_CAP_RAM; |
3c3c10bb AB |
268 | dev->mtd._erase = block2mtd_erase; |
269 | dev->mtd._write = block2mtd_write; | |
3c3c10bb AB |
270 | dev->mtd._sync = block2mtd_sync; |
271 | dev->mtd._read = block2mtd_read; | |
1da177e4 LT |
272 | dev->mtd.priv = dev; |
273 | dev->mtd.owner = THIS_MODULE; | |
274 | ||
ee0e87b1 | 275 | if (mtd_device_register(&dev->mtd, NULL, 0)) { |
25985edc | 276 | /* Device didn't get added, so free the entry */ |
1da177e4 LT |
277 | goto devinit_err; |
278 | } | |
279 | list_add(&dev->list, &blkmtd_device_list); | |
a1c06609 JP |
280 | pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n", |
281 | dev->mtd.index, | |
282 | dev->mtd.name + strlen("block2mtd: "), | |
283 | dev->mtd.erasesize >> 10, dev->mtd.erasesize); | |
1da177e4 LT |
284 | return dev; |
285 | ||
286 | devinit_err: | |
287 | block2mtd_free_device(dev); | |
288 | return NULL; | |
289 | } | |
290 | ||
291 | ||
954c2422 JE |
292 | /* This function works similar to reguler strtoul. In addition, it |
293 | * allows some suffixes for a more human-readable number format: | |
294 | * ki, Ki, kiB, KiB - multiply result with 1024 | |
295 | * Mi, MiB - multiply result with 1024^2 | |
296 | * Gi, GiB - multiply result with 1024^3 | |
297 | */ | |
1da177e4 LT |
298 | static int ustrtoul(const char *cp, char **endp, unsigned int base) |
299 | { | |
300 | unsigned long result = simple_strtoul(cp, endp, base); | |
301 | switch (**endp) { | |
302 | case 'G' : | |
303 | result *= 1024; | |
304 | case 'M': | |
305 | result *= 1024; | |
954c2422 | 306 | case 'K': |
1da177e4 LT |
307 | case 'k': |
308 | result *= 1024; | |
309 | /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ | |
954c2422 JE |
310 | if ((*endp)[1] == 'i') { |
311 | if ((*endp)[2] == 'B') | |
312 | (*endp) += 3; | |
313 | else | |
314 | (*endp) += 2; | |
315 | } | |
1da177e4 LT |
316 | } |
317 | return result; | |
318 | } | |
319 | ||
320 | ||
cc71229f | 321 | static int parse_num(size_t *num, const char *token) |
1da177e4 LT |
322 | { |
323 | char *endp; | |
cc71229f | 324 | size_t n; |
1da177e4 | 325 | |
cc71229f | 326 | n = (size_t) ustrtoul(token, &endp, 0); |
1da177e4 LT |
327 | if (*endp) |
328 | return -EINVAL; | |
329 | ||
cc71229f | 330 | *num = n; |
1da177e4 LT |
331 | return 0; |
332 | } | |
333 | ||
334 | ||
1da177e4 LT |
335 | static inline void kill_final_newline(char *str) |
336 | { | |
337 | char *newline = strrchr(str, '\n'); | |
338 | if (newline && !newline[1]) | |
339 | *newline = 0; | |
340 | } | |
341 | ||
342 | ||
c4e7fb31 VH |
343 | #ifndef MODULE |
344 | static int block2mtd_init_called = 0; | |
4839f048 | 345 | static char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */ |
c4e7fb31 VH |
346 | #endif |
347 | ||
c4e7fb31 | 348 | static int block2mtd_setup2(const char *val) |
1da177e4 | 349 | { |
c4e7fb31 | 350 | char buf[80 + 12]; /* 80 for device, 12 for erase size */ |
a6550e57 | 351 | char *str = buf; |
1da177e4 LT |
352 | char *token[2]; |
353 | char *name; | |
cc71229f | 354 | size_t erase_size = PAGE_SIZE; |
1da177e4 LT |
355 | int i, ret; |
356 | ||
a1c06609 JP |
357 | if (strnlen(val, sizeof(buf)) >= sizeof(buf)) { |
358 | pr_err("parameter too long\n"); | |
359 | return 0; | |
360 | } | |
1da177e4 LT |
361 | |
362 | strcpy(str, val); | |
363 | kill_final_newline(str); | |
364 | ||
a6550e57 | 365 | for (i = 0; i < 2; i++) |
1da177e4 LT |
366 | token[i] = strsep(&str, ","); |
367 | ||
a1c06609 JP |
368 | if (str) { |
369 | pr_err("too many arguments\n"); | |
370 | return 0; | |
371 | } | |
1da177e4 | 372 | |
a1c06609 JP |
373 | if (!token[0]) { |
374 | pr_err("no argument\n"); | |
375 | return 0; | |
376 | } | |
1da177e4 | 377 | |
c4e7fb31 | 378 | name = token[0]; |
a1c06609 JP |
379 | if (strlen(name) + 1 > 80) { |
380 | pr_err("device name too long\n"); | |
381 | return 0; | |
382 | } | |
1da177e4 LT |
383 | |
384 | if (token[1]) { | |
cc71229f | 385 | ret = parse_num(&erase_size, token[1]); |
a6550e57 | 386 | if (ret) { |
a1c06609 JP |
387 | pr_err("illegal erase size\n"); |
388 | return 0; | |
a6550e57 | 389 | } |
1da177e4 LT |
390 | } |
391 | ||
392 | add_device(name, erase_size); | |
393 | ||
394 | return 0; | |
395 | } | |
396 | ||
397 | ||
c4e7fb31 VH |
398 | static int block2mtd_setup(const char *val, struct kernel_param *kp) |
399 | { | |
400 | #ifdef MODULE | |
401 | return block2mtd_setup2(val); | |
402 | #else | |
403 | /* If more parameters are later passed in via | |
404 | /sys/module/block2mtd/parameters/block2mtd | |
405 | and block2mtd_init() has already been called, | |
406 | we can parse the argument now. */ | |
407 | ||
408 | if (block2mtd_init_called) | |
409 | return block2mtd_setup2(val); | |
410 | ||
411 | /* During early boot stage, we only save the parameters | |
412 | here. We must parse them later: if the param passed | |
413 | from kernel boot command line, block2mtd_setup() is | |
414 | called so early that it is not possible to resolve | |
415 | the device (even kmalloc() fails). Deter that work to | |
416 | block2mtd_setup2(). */ | |
417 | ||
418 | strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline)); | |
419 | ||
420 | return 0; | |
421 | #endif | |
422 | } | |
423 | ||
424 | ||
1da177e4 LT |
425 | module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200); |
426 | MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\""); | |
427 | ||
428 | static int __init block2mtd_init(void) | |
429 | { | |
c4e7fb31 | 430 | int ret = 0; |
c4e7fb31 VH |
431 | |
432 | #ifndef MODULE | |
433 | if (strlen(block2mtd_paramline)) | |
434 | ret = block2mtd_setup2(block2mtd_paramline); | |
435 | block2mtd_init_called = 1; | |
436 | #endif | |
437 | ||
438 | return ret; | |
1da177e4 LT |
439 | } |
440 | ||
441 | ||
810b7e06 | 442 | static void block2mtd_exit(void) |
1da177e4 LT |
443 | { |
444 | struct list_head *pos, *next; | |
445 | ||
446 | /* Remove the MTD devices */ | |
447 | list_for_each_safe(pos, next, &blkmtd_device_list) { | |
448 | struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list); | |
449 | block2mtd_sync(&dev->mtd); | |
ee0e87b1 | 450 | mtd_device_unregister(&dev->mtd); |
a1c06609 JP |
451 | pr_info("mtd%d: [%s] removed\n", |
452 | dev->mtd.index, | |
453 | dev->mtd.name + strlen("block2mtd: ")); | |
1da177e4 LT |
454 | list_del(&dev->list); |
455 | block2mtd_free_device(dev); | |
456 | } | |
457 | } | |
458 | ||
459 | ||
460 | module_init(block2mtd_init); | |
461 | module_exit(block2mtd_exit); | |
462 | ||
463 | MODULE_LICENSE("GPL"); | |
2b54aaef | 464 | MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>"); |
1da177e4 | 465 | MODULE_DESCRIPTION("Emulate an MTD using a block device"); |