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 | ||
d6a3f017 FF |
12 | /* |
13 | * When the first attempt at device initialization fails, we may need to | |
14 | * wait a little bit and retry. This timeout, by default 3 seconds, gives | |
15 | * device time to start up. Required on BCM2708 and a few other chipsets. | |
16 | */ | |
17 | #define MTD_DEFAULT_TIMEOUT 3 | |
18 | ||
1da177e4 | 19 | #include <linux/module.h> |
d6a3f017 | 20 | #include <linux/delay.h> |
1da177e4 LT |
21 | #include <linux/fs.h> |
22 | #include <linux/blkdev.h> | |
66114cad | 23 | #include <linux/backing-dev.h> |
1da177e4 LT |
24 | #include <linux/bio.h> |
25 | #include <linux/pagemap.h> | |
26 | #include <linux/list.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/mtd/mtd.h> | |
48b19268 | 29 | #include <linux/mutex.h> |
c4e7fb31 | 30 | #include <linux/mount.h> |
5a0e3ad6 | 31 | #include <linux/slab.h> |
f83c3838 | 32 | #include <linux/major.h> |
1da177e4 | 33 | |
1da177e4 LT |
34 | /* Info for the block device */ |
35 | struct block2mtd_dev { | |
36 | struct list_head list; | |
37 | struct block_device *blkdev; | |
38 | struct mtd_info mtd; | |
48b19268 | 39 | struct mutex write_mutex; |
1da177e4 LT |
40 | }; |
41 | ||
42 | ||
43 | /* Static info about the MTD, used in cleanup_module */ | |
44 | static LIST_HEAD(blkmtd_device_list); | |
45 | ||
46 | ||
6fe6900e | 47 | static struct page *page_read(struct address_space *mapping, int index) |
1da177e4 | 48 | { |
6fe6900e | 49 | return read_mapping_page(mapping, index, NULL); |
1da177e4 LT |
50 | } |
51 | ||
1da177e4 LT |
52 | /* erase a specified part of the device */ |
53 | static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len) | |
54 | { | |
55 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
56 | struct page *page; | |
57 | int index = to >> PAGE_SHIFT; // page index | |
58 | int pages = len >> PAGE_SHIFT; | |
59 | u_long *p; | |
60 | u_long *max; | |
61 | ||
62 | while (pages) { | |
21d31f1f | 63 | page = page_read(mapping, index); |
1da177e4 LT |
64 | if (IS_ERR(page)) |
65 | return PTR_ERR(page); | |
66 | ||
0ffb74cc JE |
67 | max = page_address(page) + PAGE_SIZE; |
68 | for (p=page_address(page); p<max; p++) | |
1da177e4 LT |
69 | if (*p != -1UL) { |
70 | lock_page(page); | |
71 | memset(page_address(page), 0xff, PAGE_SIZE); | |
72 | set_page_dirty(page); | |
73 | unlock_page(page); | |
031da73f | 74 | balance_dirty_pages_ratelimited(mapping); |
1da177e4 LT |
75 | break; |
76 | } | |
77 | ||
09cbfeaf | 78 | put_page(page); |
1da177e4 LT |
79 | pages--; |
80 | index++; | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr) | |
85 | { | |
86 | struct block2mtd_dev *dev = mtd->priv; | |
87 | size_t from = instr->addr; | |
88 | size_t len = instr->len; | |
89 | int err; | |
90 | ||
91 | instr->state = MTD_ERASING; | |
48b19268 | 92 | mutex_lock(&dev->write_mutex); |
1da177e4 | 93 | err = _block2mtd_erase(dev, from, len); |
48b19268 | 94 | mutex_unlock(&dev->write_mutex); |
1da177e4 | 95 | if (err) { |
a1c06609 | 96 | pr_err("erase failed err = %d\n", err); |
1da177e4 LT |
97 | instr->state = MTD_ERASE_FAILED; |
98 | } else | |
99 | instr->state = MTD_ERASE_DONE; | |
100 | ||
1da177e4 LT |
101 | mtd_erase_callback(instr); |
102 | return err; | |
103 | } | |
104 | ||
105 | ||
106 | static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len, | |
107 | size_t *retlen, u_char *buf) | |
108 | { | |
109 | struct block2mtd_dev *dev = mtd->priv; | |
110 | struct page *page; | |
111 | int index = from >> PAGE_SHIFT; | |
711c11b7 | 112 | int offset = from & (PAGE_SIZE-1); |
1da177e4 LT |
113 | int cpylen; |
114 | ||
1da177e4 LT |
115 | while (len) { |
116 | if ((offset + len) > PAGE_SIZE) | |
117 | cpylen = PAGE_SIZE - offset; // multiple pages | |
118 | else | |
119 | cpylen = len; // this page | |
120 | len = len - cpylen; | |
121 | ||
21d31f1f | 122 | page = page_read(dev->blkdev->bd_inode->i_mapping, index); |
1da177e4 LT |
123 | if (IS_ERR(page)) |
124 | return PTR_ERR(page); | |
125 | ||
126 | memcpy(buf, page_address(page) + offset, cpylen); | |
09cbfeaf | 127 | put_page(page); |
1da177e4 LT |
128 | |
129 | if (retlen) | |
130 | *retlen += cpylen; | |
131 | buf += cpylen; | |
132 | offset = 0; | |
133 | index++; | |
134 | } | |
135 | return 0; | |
136 | } | |
137 | ||
138 | ||
139 | /* write data to the underlying device */ | |
140 | static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf, | |
141 | loff_t to, size_t len, size_t *retlen) | |
142 | { | |
143 | struct page *page; | |
144 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
145 | int index = to >> PAGE_SHIFT; // page index | |
146 | int offset = to & ~PAGE_MASK; // page offset | |
147 | int cpylen; | |
148 | ||
1da177e4 | 149 | while (len) { |
e5580fbe | 150 | if ((offset+len) > PAGE_SIZE) |
1da177e4 LT |
151 | cpylen = PAGE_SIZE - offset; // multiple pages |
152 | else | |
153 | cpylen = len; // this page | |
154 | len = len - cpylen; | |
155 | ||
21d31f1f | 156 | page = page_read(mapping, index); |
1da177e4 LT |
157 | if (IS_ERR(page)) |
158 | return PTR_ERR(page); | |
159 | ||
160 | if (memcmp(page_address(page)+offset, buf, cpylen)) { | |
161 | lock_page(page); | |
162 | memcpy(page_address(page) + offset, buf, cpylen); | |
163 | set_page_dirty(page); | |
164 | unlock_page(page); | |
031da73f | 165 | balance_dirty_pages_ratelimited(mapping); |
1da177e4 | 166 | } |
09cbfeaf | 167 | put_page(page); |
1da177e4 LT |
168 | |
169 | if (retlen) | |
170 | *retlen += cpylen; | |
171 | ||
172 | buf += cpylen; | |
173 | offset = 0; | |
174 | index++; | |
175 | } | |
176 | return 0; | |
177 | } | |
c4e7fb31 VH |
178 | |
179 | ||
1da177e4 LT |
180 | static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len, |
181 | size_t *retlen, const u_char *buf) | |
182 | { | |
183 | struct block2mtd_dev *dev = mtd->priv; | |
184 | int err; | |
185 | ||
48b19268 | 186 | mutex_lock(&dev->write_mutex); |
1da177e4 | 187 | err = _block2mtd_write(dev, buf, to, len, retlen); |
48b19268 | 188 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
189 | if (err > 0) |
190 | err = 0; | |
191 | return err; | |
192 | } | |
193 | ||
194 | ||
195 | /* sync the device - wait until the write queue is empty */ | |
196 | static void block2mtd_sync(struct mtd_info *mtd) | |
197 | { | |
198 | struct block2mtd_dev *dev = mtd->priv; | |
199 | sync_blockdev(dev->blkdev); | |
200 | return; | |
201 | } | |
202 | ||
203 | ||
204 | static void block2mtd_free_device(struct block2mtd_dev *dev) | |
205 | { | |
206 | if (!dev) | |
207 | return; | |
208 | ||
209 | kfree(dev->mtd.name); | |
210 | ||
211 | if (dev->blkdev) { | |
fc0ecff6 AM |
212 | invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, |
213 | 0, -1); | |
e525fd89 | 214 | blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
1da177e4 LT |
215 | } |
216 | ||
217 | kfree(dev); | |
218 | } | |
219 | ||
220 | ||
d6a3f017 FF |
221 | static struct block2mtd_dev *add_device(char *devname, int erase_size, |
222 | int timeout) | |
1da177e4 | 223 | { |
d6a3f017 FF |
224 | #ifndef MODULE |
225 | int i; | |
226 | #endif | |
e525fd89 | 227 | const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; |
d6a3f017 | 228 | struct block_device *bdev = ERR_PTR(-ENODEV); |
1da177e4 | 229 | struct block2mtd_dev *dev; |
eadcf0d7 | 230 | char *name; |
1da177e4 LT |
231 | |
232 | if (!devname) | |
233 | return NULL; | |
234 | ||
95b93a0c | 235 | dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL); |
1da177e4 LT |
236 | if (!dev) |
237 | return NULL; | |
1da177e4 LT |
238 | |
239 | /* Get a handle on the device */ | |
d4d77629 | 240 | bdev = blkdev_get_by_path(devname, mode, dev); |
c4e7fb31 | 241 | |
d6a3f017 FF |
242 | #ifndef MODULE |
243 | /* | |
244 | * We might not have the root device mounted at this point. | |
245 | * Try to resolve the device name by other means. | |
246 | */ | |
247 | for (i = 0; IS_ERR(bdev) && i <= timeout; i++) { | |
248 | dev_t devt; | |
249 | ||
250 | if (i) | |
251 | /* | |
252 | * Calling wait_for_device_probe in the first loop | |
253 | * was not enough, sleep for a bit in subsequent | |
254 | * go-arounds. | |
255 | */ | |
256 | msleep(1000); | |
257 | wait_for_device_probe(); | |
258 | ||
259 | devt = name_to_dev_t(devname); | |
260 | if (!devt) | |
261 | continue; | |
262 | bdev = blkdev_get_by_dev(devt, mode, dev); | |
c4e7fb31 VH |
263 | } |
264 | #endif | |
265 | ||
1da177e4 | 266 | if (IS_ERR(bdev)) { |
a1c06609 | 267 | pr_err("error: cannot open device %s\n", devname); |
4bed207c | 268 | goto err_free_block2mtd; |
1da177e4 LT |
269 | } |
270 | dev->blkdev = bdev; | |
271 | ||
272 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
a1c06609 | 273 | pr_err("attempting to use an MTD device as a block device\n"); |
4bed207c | 274 | goto err_free_block2mtd; |
1da177e4 LT |
275 | } |
276 | ||
ea6d833a FF |
277 | if ((long)dev->blkdev->bd_inode->i_size % erase_size) { |
278 | pr_err("erasesize must be a divisor of device size\n"); | |
279 | goto err_free_block2mtd; | |
280 | } | |
281 | ||
48b19268 | 282 | mutex_init(&dev->write_mutex); |
1da177e4 LT |
283 | |
284 | /* Setup the MTD structure */ | |
285 | /* make the name contain the block device in */ | |
4d682420 | 286 | name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname); |
eadcf0d7 | 287 | if (!name) |
4bed207c | 288 | goto err_destroy_mutex; |
1da177e4 | 289 | |
eadcf0d7 | 290 | dev->mtd.name = name; |
1da177e4 LT |
291 | |
292 | dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK; | |
293 | dev->mtd.erasesize = erase_size; | |
17ffc7ba | 294 | dev->mtd.writesize = 1; |
b6043874 | 295 | dev->mtd.writebufsize = PAGE_SIZE; |
21c8db9e | 296 | dev->mtd.type = MTD_RAM; |
1da177e4 | 297 | dev->mtd.flags = MTD_CAP_RAM; |
3c3c10bb AB |
298 | dev->mtd._erase = block2mtd_erase; |
299 | dev->mtd._write = block2mtd_write; | |
3c3c10bb AB |
300 | dev->mtd._sync = block2mtd_sync; |
301 | dev->mtd._read = block2mtd_read; | |
1da177e4 LT |
302 | dev->mtd.priv = dev; |
303 | dev->mtd.owner = THIS_MODULE; | |
304 | ||
ee0e87b1 | 305 | if (mtd_device_register(&dev->mtd, NULL, 0)) { |
25985edc | 306 | /* Device didn't get added, so free the entry */ |
4bed207c | 307 | goto err_destroy_mutex; |
1da177e4 | 308 | } |
d6a3f017 | 309 | |
1da177e4 | 310 | list_add(&dev->list, &blkmtd_device_list); |
a1c06609 JP |
311 | pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n", |
312 | dev->mtd.index, | |
313 | dev->mtd.name + strlen("block2mtd: "), | |
314 | dev->mtd.erasesize >> 10, dev->mtd.erasesize); | |
1da177e4 LT |
315 | return dev; |
316 | ||
4bed207c FF |
317 | err_destroy_mutex: |
318 | mutex_destroy(&dev->write_mutex); | |
319 | err_free_block2mtd: | |
1da177e4 LT |
320 | block2mtd_free_device(dev); |
321 | return NULL; | |
322 | } | |
323 | ||
324 | ||
954c2422 JE |
325 | /* This function works similar to reguler strtoul. In addition, it |
326 | * allows some suffixes for a more human-readable number format: | |
327 | * ki, Ki, kiB, KiB - multiply result with 1024 | |
328 | * Mi, MiB - multiply result with 1024^2 | |
329 | * Gi, GiB - multiply result with 1024^3 | |
330 | */ | |
1da177e4 LT |
331 | static int ustrtoul(const char *cp, char **endp, unsigned int base) |
332 | { | |
333 | unsigned long result = simple_strtoul(cp, endp, base); | |
334 | switch (**endp) { | |
335 | case 'G' : | |
336 | result *= 1024; | |
337 | case 'M': | |
338 | result *= 1024; | |
954c2422 | 339 | case 'K': |
1da177e4 LT |
340 | case 'k': |
341 | result *= 1024; | |
342 | /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ | |
954c2422 JE |
343 | if ((*endp)[1] == 'i') { |
344 | if ((*endp)[2] == 'B') | |
345 | (*endp) += 3; | |
346 | else | |
347 | (*endp) += 2; | |
348 | } | |
1da177e4 LT |
349 | } |
350 | return result; | |
351 | } | |
352 | ||
353 | ||
cc71229f | 354 | static int parse_num(size_t *num, const char *token) |
1da177e4 LT |
355 | { |
356 | char *endp; | |
cc71229f | 357 | size_t n; |
1da177e4 | 358 | |
cc71229f | 359 | n = (size_t) ustrtoul(token, &endp, 0); |
1da177e4 LT |
360 | if (*endp) |
361 | return -EINVAL; | |
362 | ||
cc71229f | 363 | *num = n; |
1da177e4 LT |
364 | return 0; |
365 | } | |
366 | ||
367 | ||
1da177e4 LT |
368 | static inline void kill_final_newline(char *str) |
369 | { | |
370 | char *newline = strrchr(str, '\n'); | |
371 | if (newline && !newline[1]) | |
372 | *newline = 0; | |
373 | } | |
374 | ||
375 | ||
c4e7fb31 VH |
376 | #ifndef MODULE |
377 | static int block2mtd_init_called = 0; | |
d6a3f017 FF |
378 | /* 80 for device, 12 for erase size */ |
379 | static char block2mtd_paramline[80 + 12]; | |
c4e7fb31 VH |
380 | #endif |
381 | ||
c4e7fb31 | 382 | static int block2mtd_setup2(const char *val) |
1da177e4 | 383 | { |
d6a3f017 FF |
384 | /* 80 for device, 12 for erase size, 80 for name, 8 for timeout */ |
385 | char buf[80 + 12 + 80 + 8]; | |
a6550e57 | 386 | char *str = buf; |
1da177e4 LT |
387 | char *token[2]; |
388 | char *name; | |
cc71229f | 389 | size_t erase_size = PAGE_SIZE; |
d6a3f017 | 390 | unsigned long timeout = MTD_DEFAULT_TIMEOUT; |
1da177e4 LT |
391 | int i, ret; |
392 | ||
a1c06609 JP |
393 | if (strnlen(val, sizeof(buf)) >= sizeof(buf)) { |
394 | pr_err("parameter too long\n"); | |
395 | return 0; | |
396 | } | |
1da177e4 LT |
397 | |
398 | strcpy(str, val); | |
399 | kill_final_newline(str); | |
400 | ||
a6550e57 | 401 | for (i = 0; i < 2; i++) |
1da177e4 LT |
402 | token[i] = strsep(&str, ","); |
403 | ||
a1c06609 JP |
404 | if (str) { |
405 | pr_err("too many arguments\n"); | |
406 | return 0; | |
407 | } | |
1da177e4 | 408 | |
a1c06609 JP |
409 | if (!token[0]) { |
410 | pr_err("no argument\n"); | |
411 | return 0; | |
412 | } | |
1da177e4 | 413 | |
c4e7fb31 | 414 | name = token[0]; |
a1c06609 JP |
415 | if (strlen(name) + 1 > 80) { |
416 | pr_err("device name too long\n"); | |
417 | return 0; | |
418 | } | |
1da177e4 LT |
419 | |
420 | if (token[1]) { | |
cc71229f | 421 | ret = parse_num(&erase_size, token[1]); |
a6550e57 | 422 | if (ret) { |
a1c06609 JP |
423 | pr_err("illegal erase size\n"); |
424 | return 0; | |
a6550e57 | 425 | } |
1da177e4 LT |
426 | } |
427 | ||
d6a3f017 | 428 | add_device(name, erase_size, timeout); |
1da177e4 LT |
429 | |
430 | return 0; | |
431 | } | |
432 | ||
433 | ||
c4e7fb31 VH |
434 | static int block2mtd_setup(const char *val, struct kernel_param *kp) |
435 | { | |
436 | #ifdef MODULE | |
437 | return block2mtd_setup2(val); | |
438 | #else | |
439 | /* If more parameters are later passed in via | |
440 | /sys/module/block2mtd/parameters/block2mtd | |
441 | and block2mtd_init() has already been called, | |
442 | we can parse the argument now. */ | |
443 | ||
444 | if (block2mtd_init_called) | |
445 | return block2mtd_setup2(val); | |
446 | ||
447 | /* During early boot stage, we only save the parameters | |
448 | here. We must parse them later: if the param passed | |
449 | from kernel boot command line, block2mtd_setup() is | |
450 | called so early that it is not possible to resolve | |
451 | the device (even kmalloc() fails). Deter that work to | |
452 | block2mtd_setup2(). */ | |
453 | ||
454 | strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline)); | |
455 | ||
456 | return 0; | |
457 | #endif | |
458 | } | |
459 | ||
460 | ||
1da177e4 LT |
461 | module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200); |
462 | MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\""); | |
463 | ||
464 | static int __init block2mtd_init(void) | |
465 | { | |
c4e7fb31 | 466 | int ret = 0; |
c4e7fb31 VH |
467 | |
468 | #ifndef MODULE | |
469 | if (strlen(block2mtd_paramline)) | |
470 | ret = block2mtd_setup2(block2mtd_paramline); | |
471 | block2mtd_init_called = 1; | |
472 | #endif | |
473 | ||
474 | return ret; | |
1da177e4 LT |
475 | } |
476 | ||
477 | ||
810b7e06 | 478 | static void block2mtd_exit(void) |
1da177e4 LT |
479 | { |
480 | struct list_head *pos, *next; | |
481 | ||
482 | /* Remove the MTD devices */ | |
483 | list_for_each_safe(pos, next, &blkmtd_device_list) { | |
484 | struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list); | |
485 | block2mtd_sync(&dev->mtd); | |
ee0e87b1 | 486 | mtd_device_unregister(&dev->mtd); |
4bed207c | 487 | mutex_destroy(&dev->write_mutex); |
a1c06609 JP |
488 | pr_info("mtd%d: [%s] removed\n", |
489 | dev->mtd.index, | |
490 | dev->mtd.name + strlen("block2mtd: ")); | |
1da177e4 LT |
491 | list_del(&dev->list); |
492 | block2mtd_free_device(dev); | |
493 | } | |
494 | } | |
495 | ||
d6a3f017 | 496 | late_initcall(block2mtd_init); |
1da177e4 LT |
497 | module_exit(block2mtd_exit); |
498 | ||
499 | MODULE_LICENSE("GPL"); | |
2b54aaef | 500 | MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>"); |
1da177e4 | 501 | MODULE_DESCRIPTION("Emulate an MTD using a block device"); |