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 | */ | |
1da177e4 LT |
9 | #include <linux/module.h> |
10 | #include <linux/fs.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/bio.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/list.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/mtd/mtd.h> | |
48b19268 | 17 | #include <linux/mutex.h> |
c4e7fb31 | 18 | #include <linux/mount.h> |
5a0e3ad6 | 19 | #include <linux/slab.h> |
1da177e4 | 20 | |
1da177e4 LT |
21 | #define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args) |
22 | #define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args) | |
23 | ||
24 | ||
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 (!page) |
56 | return -ENOMEM; | |
57 | if (IS_ERR(page)) | |
58 | return PTR_ERR(page); | |
59 | ||
0ffb74cc JE |
60 | max = page_address(page) + PAGE_SIZE; |
61 | for (p=page_address(page); p<max; p++) | |
1da177e4 LT |
62 | if (*p != -1UL) { |
63 | lock_page(page); | |
64 | memset(page_address(page), 0xff, PAGE_SIZE); | |
65 | set_page_dirty(page); | |
66 | unlock_page(page); | |
67 | break; | |
68 | } | |
69 | ||
70 | page_cache_release(page); | |
71 | pages--; | |
72 | index++; | |
73 | } | |
74 | return 0; | |
75 | } | |
76 | static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr) | |
77 | { | |
78 | struct block2mtd_dev *dev = mtd->priv; | |
79 | size_t from = instr->addr; | |
80 | size_t len = instr->len; | |
81 | int err; | |
82 | ||
83 | instr->state = MTD_ERASING; | |
48b19268 | 84 | mutex_lock(&dev->write_mutex); |
1da177e4 | 85 | err = _block2mtd_erase(dev, from, len); |
48b19268 | 86 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
87 | if (err) { |
88 | ERROR("erase failed err = %d", err); | |
89 | instr->state = MTD_ERASE_FAILED; | |
90 | } else | |
91 | instr->state = MTD_ERASE_DONE; | |
92 | ||
1da177e4 LT |
93 | mtd_erase_callback(instr); |
94 | return err; | |
95 | } | |
96 | ||
97 | ||
98 | static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len, | |
99 | size_t *retlen, u_char *buf) | |
100 | { | |
101 | struct block2mtd_dev *dev = mtd->priv; | |
102 | struct page *page; | |
103 | int index = from >> PAGE_SHIFT; | |
711c11b7 | 104 | int offset = from & (PAGE_SIZE-1); |
1da177e4 LT |
105 | int cpylen; |
106 | ||
107 | if (from > mtd->size) | |
108 | return -EINVAL; | |
109 | if (from + len > mtd->size) | |
110 | len = mtd->size - from; | |
111 | ||
112 | if (retlen) | |
113 | *retlen = 0; | |
114 | ||
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 (!page) |
124 | return -ENOMEM; | |
125 | if (IS_ERR(page)) | |
126 | return PTR_ERR(page); | |
127 | ||
128 | memcpy(buf, page_address(page) + offset, cpylen); | |
129 | page_cache_release(page); | |
130 | ||
131 | if (retlen) | |
132 | *retlen += cpylen; | |
133 | buf += cpylen; | |
134 | offset = 0; | |
135 | index++; | |
136 | } | |
137 | return 0; | |
138 | } | |
139 | ||
140 | ||
141 | /* write data to the underlying device */ | |
142 | static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf, | |
143 | loff_t to, size_t len, size_t *retlen) | |
144 | { | |
145 | struct page *page; | |
146 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
147 | int index = to >> PAGE_SHIFT; // page index | |
148 | int offset = to & ~PAGE_MASK; // page offset | |
149 | int cpylen; | |
150 | ||
151 | if (retlen) | |
152 | *retlen = 0; | |
153 | while (len) { | |
e5580fbe | 154 | if ((offset+len) > PAGE_SIZE) |
1da177e4 LT |
155 | cpylen = PAGE_SIZE - offset; // multiple pages |
156 | else | |
157 | cpylen = len; // this page | |
158 | len = len - cpylen; | |
159 | ||
21d31f1f | 160 | page = page_read(mapping, index); |
1da177e4 LT |
161 | if (!page) |
162 | return -ENOMEM; | |
163 | if (IS_ERR(page)) | |
164 | return PTR_ERR(page); | |
165 | ||
166 | if (memcmp(page_address(page)+offset, buf, cpylen)) { | |
167 | lock_page(page); | |
168 | memcpy(page_address(page) + offset, buf, cpylen); | |
169 | set_page_dirty(page); | |
170 | unlock_page(page); | |
171 | } | |
172 | page_cache_release(page); | |
173 | ||
174 | if (retlen) | |
175 | *retlen += cpylen; | |
176 | ||
177 | buf += cpylen; | |
178 | offset = 0; | |
179 | index++; | |
180 | } | |
181 | return 0; | |
182 | } | |
c4e7fb31 VH |
183 | |
184 | ||
1da177e4 LT |
185 | static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len, |
186 | size_t *retlen, const u_char *buf) | |
187 | { | |
188 | struct block2mtd_dev *dev = mtd->priv; | |
189 | int err; | |
190 | ||
191 | if (!len) | |
192 | return 0; | |
193 | if (to >= mtd->size) | |
194 | return -ENOSPC; | |
195 | if (to + len > mtd->size) | |
196 | len = mtd->size - to; | |
197 | ||
48b19268 | 198 | mutex_lock(&dev->write_mutex); |
1da177e4 | 199 | err = _block2mtd_write(dev, buf, to, len, retlen); |
48b19268 | 200 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
201 | if (err > 0) |
202 | err = 0; | |
203 | return err; | |
204 | } | |
205 | ||
206 | ||
207 | /* sync the device - wait until the write queue is empty */ | |
208 | static void block2mtd_sync(struct mtd_info *mtd) | |
209 | { | |
210 | struct block2mtd_dev *dev = mtd->priv; | |
211 | sync_blockdev(dev->blkdev); | |
212 | return; | |
213 | } | |
214 | ||
215 | ||
216 | static void block2mtd_free_device(struct block2mtd_dev *dev) | |
217 | { | |
218 | if (!dev) | |
219 | return; | |
220 | ||
221 | kfree(dev->mtd.name); | |
222 | ||
223 | if (dev->blkdev) { | |
fc0ecff6 AM |
224 | invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, |
225 | 0, -1); | |
e525fd89 | 226 | blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
1da177e4 LT |
227 | } |
228 | ||
229 | kfree(dev); | |
230 | } | |
231 | ||
232 | ||
233 | /* FIXME: ensure that mtd->size % erase_size == 0 */ | |
234 | static struct block2mtd_dev *add_device(char *devname, int erase_size) | |
235 | { | |
e525fd89 | 236 | const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; |
1da177e4 LT |
237 | struct block_device *bdev; |
238 | struct block2mtd_dev *dev; | |
eadcf0d7 | 239 | char *name; |
1da177e4 LT |
240 | |
241 | if (!devname) | |
242 | return NULL; | |
243 | ||
95b93a0c | 244 | dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL); |
1da177e4 LT |
245 | if (!dev) |
246 | return NULL; | |
1da177e4 LT |
247 | |
248 | /* Get a handle on the device */ | |
d4d77629 | 249 | bdev = blkdev_get_by_path(devname, mode, dev); |
c4e7fb31 VH |
250 | #ifndef MODULE |
251 | if (IS_ERR(bdev)) { | |
252 | ||
253 | /* We might not have rootfs mounted at this point. Try | |
254 | to resolve the device name by other means. */ | |
255 | ||
8870530a | 256 | dev_t devt = name_to_dev_t(devname); |
e525fd89 | 257 | if (devt) |
d4d77629 | 258 | bdev = blkdev_get_by_dev(devt, mode, dev); |
c4e7fb31 VH |
259 | } |
260 | #endif | |
261 | ||
1da177e4 LT |
262 | if (IS_ERR(bdev)) { |
263 | ERROR("error: cannot open device %s", devname); | |
264 | goto devinit_err; | |
265 | } | |
266 | dev->blkdev = bdev; | |
267 | ||
268 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
269 | ERROR("attempting to use an MTD device as a block device"); | |
270 | goto devinit_err; | |
271 | } | |
272 | ||
48b19268 | 273 | mutex_init(&dev->write_mutex); |
1da177e4 LT |
274 | |
275 | /* Setup the MTD structure */ | |
276 | /* make the name contain the block device in */ | |
4d682420 | 277 | name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname); |
eadcf0d7 | 278 | if (!name) |
1da177e4 LT |
279 | goto devinit_err; |
280 | ||
eadcf0d7 | 281 | dev->mtd.name = name; |
1da177e4 LT |
282 | |
283 | dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK; | |
284 | dev->mtd.erasesize = erase_size; | |
17ffc7ba | 285 | dev->mtd.writesize = 1; |
21c8db9e | 286 | dev->mtd.type = MTD_RAM; |
1da177e4 LT |
287 | dev->mtd.flags = MTD_CAP_RAM; |
288 | dev->mtd.erase = block2mtd_erase; | |
289 | dev->mtd.write = block2mtd_write; | |
290 | dev->mtd.writev = default_mtd_writev; | |
291 | dev->mtd.sync = block2mtd_sync; | |
292 | dev->mtd.read = block2mtd_read; | |
1da177e4 LT |
293 | dev->mtd.priv = dev; |
294 | dev->mtd.owner = THIS_MODULE; | |
295 | ||
ee0e87b1 | 296 | if (mtd_device_register(&dev->mtd, NULL, 0)) { |
25985edc | 297 | /* Device didn't get added, so free the entry */ |
1da177e4 LT |
298 | goto devinit_err; |
299 | } | |
300 | list_add(&dev->list, &blkmtd_device_list); | |
301 | INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index, | |
0bc88c59 | 302 | dev->mtd.name + strlen("block2mtd: "), |
1da177e4 LT |
303 | dev->mtd.erasesize >> 10, dev->mtd.erasesize); |
304 | return dev; | |
305 | ||
306 | devinit_err: | |
307 | block2mtd_free_device(dev); | |
308 | return NULL; | |
309 | } | |
310 | ||
311 | ||
954c2422 JE |
312 | /* This function works similar to reguler strtoul. In addition, it |
313 | * allows some suffixes for a more human-readable number format: | |
314 | * ki, Ki, kiB, KiB - multiply result with 1024 | |
315 | * Mi, MiB - multiply result with 1024^2 | |
316 | * Gi, GiB - multiply result with 1024^3 | |
317 | */ | |
1da177e4 LT |
318 | static int ustrtoul(const char *cp, char **endp, unsigned int base) |
319 | { | |
320 | unsigned long result = simple_strtoul(cp, endp, base); | |
321 | switch (**endp) { | |
322 | case 'G' : | |
323 | result *= 1024; | |
324 | case 'M': | |
325 | result *= 1024; | |
954c2422 | 326 | case 'K': |
1da177e4 LT |
327 | case 'k': |
328 | result *= 1024; | |
329 | /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ | |
954c2422 JE |
330 | if ((*endp)[1] == 'i') { |
331 | if ((*endp)[2] == 'B') | |
332 | (*endp) += 3; | |
333 | else | |
334 | (*endp) += 2; | |
335 | } | |
1da177e4 LT |
336 | } |
337 | return result; | |
338 | } | |
339 | ||
340 | ||
cc71229f | 341 | static int parse_num(size_t *num, const char *token) |
1da177e4 LT |
342 | { |
343 | char *endp; | |
cc71229f | 344 | size_t n; |
1da177e4 | 345 | |
cc71229f | 346 | n = (size_t) ustrtoul(token, &endp, 0); |
1da177e4 LT |
347 | if (*endp) |
348 | return -EINVAL; | |
349 | ||
cc71229f | 350 | *num = n; |
1da177e4 LT |
351 | return 0; |
352 | } | |
353 | ||
354 | ||
1da177e4 LT |
355 | static inline void kill_final_newline(char *str) |
356 | { | |
357 | char *newline = strrchr(str, '\n'); | |
358 | if (newline && !newline[1]) | |
359 | *newline = 0; | |
360 | } | |
361 | ||
362 | ||
0bc88c59 SC |
363 | #define parse_err(fmt, args...) do { \ |
364 | ERROR(fmt, ## args); \ | |
365 | return 0; \ | |
1da177e4 LT |
366 | } while (0) |
367 | ||
c4e7fb31 VH |
368 | #ifndef MODULE |
369 | static int block2mtd_init_called = 0; | |
4839f048 | 370 | static char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */ |
c4e7fb31 VH |
371 | #endif |
372 | ||
373 | ||
374 | static int block2mtd_setup2(const char *val) | |
1da177e4 | 375 | { |
c4e7fb31 | 376 | char buf[80 + 12]; /* 80 for device, 12 for erase size */ |
a6550e57 | 377 | char *str = buf; |
1da177e4 LT |
378 | char *token[2]; |
379 | char *name; | |
cc71229f | 380 | size_t erase_size = PAGE_SIZE; |
1da177e4 LT |
381 | int i, ret; |
382 | ||
383 | if (strnlen(val, sizeof(buf)) >= sizeof(buf)) | |
384 | parse_err("parameter too long"); | |
385 | ||
386 | strcpy(str, val); | |
387 | kill_final_newline(str); | |
388 | ||
a6550e57 | 389 | for (i = 0; i < 2; i++) |
1da177e4 LT |
390 | token[i] = strsep(&str, ","); |
391 | ||
392 | if (str) | |
393 | parse_err("too many arguments"); | |
394 | ||
395 | if (!token[0]) | |
396 | parse_err("no argument"); | |
397 | ||
c4e7fb31 VH |
398 | name = token[0]; |
399 | if (strlen(name) + 1 > 80) | |
400 | parse_err("device name too long"); | |
1da177e4 LT |
401 | |
402 | if (token[1]) { | |
cc71229f | 403 | ret = parse_num(&erase_size, token[1]); |
a6550e57 | 404 | if (ret) { |
1da177e4 | 405 | parse_err("illegal erase size"); |
a6550e57 | 406 | } |
1da177e4 LT |
407 | } |
408 | ||
409 | add_device(name, erase_size); | |
410 | ||
411 | return 0; | |
412 | } | |
413 | ||
414 | ||
c4e7fb31 VH |
415 | static int block2mtd_setup(const char *val, struct kernel_param *kp) |
416 | { | |
417 | #ifdef MODULE | |
418 | return block2mtd_setup2(val); | |
419 | #else | |
420 | /* If more parameters are later passed in via | |
421 | /sys/module/block2mtd/parameters/block2mtd | |
422 | and block2mtd_init() has already been called, | |
423 | we can parse the argument now. */ | |
424 | ||
425 | if (block2mtd_init_called) | |
426 | return block2mtd_setup2(val); | |
427 | ||
428 | /* During early boot stage, we only save the parameters | |
429 | here. We must parse them later: if the param passed | |
430 | from kernel boot command line, block2mtd_setup() is | |
431 | called so early that it is not possible to resolve | |
432 | the device (even kmalloc() fails). Deter that work to | |
433 | block2mtd_setup2(). */ | |
434 | ||
435 | strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline)); | |
436 | ||
437 | return 0; | |
438 | #endif | |
439 | } | |
440 | ||
441 | ||
1da177e4 LT |
442 | module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200); |
443 | MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\""); | |
444 | ||
445 | static int __init block2mtd_init(void) | |
446 | { | |
c4e7fb31 | 447 | int ret = 0; |
c4e7fb31 VH |
448 | |
449 | #ifndef MODULE | |
450 | if (strlen(block2mtd_paramline)) | |
451 | ret = block2mtd_setup2(block2mtd_paramline); | |
452 | block2mtd_init_called = 1; | |
453 | #endif | |
454 | ||
455 | return ret; | |
1da177e4 LT |
456 | } |
457 | ||
458 | ||
459 | static void __devexit block2mtd_exit(void) | |
460 | { | |
461 | struct list_head *pos, *next; | |
462 | ||
463 | /* Remove the MTD devices */ | |
464 | list_for_each_safe(pos, next, &blkmtd_device_list) { | |
465 | struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list); | |
466 | block2mtd_sync(&dev->mtd); | |
ee0e87b1 | 467 | mtd_device_unregister(&dev->mtd); |
1da177e4 | 468 | INFO("mtd%d: [%s] removed", dev->mtd.index, |
0bc88c59 | 469 | dev->mtd.name + strlen("block2mtd: ")); |
1da177e4 LT |
470 | list_del(&dev->list); |
471 | block2mtd_free_device(dev); | |
472 | } | |
473 | } | |
474 | ||
475 | ||
476 | module_init(block2mtd_init); | |
477 | module_exit(block2mtd_exit); | |
478 | ||
479 | MODULE_LICENSE("GPL"); | |
2b54aaef | 480 | MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>"); |
1da177e4 | 481 | MODULE_DESCRIPTION("Emulate an MTD using a block device"); |