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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 | */ | |
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> | |
17 | #include <linux/buffer_head.h> | |
48b19268 | 18 | #include <linux/mutex.h> |
c4e7fb31 | 19 | #include <linux/mount.h> |
5a0e3ad6 | 20 | #include <linux/slab.h> |
1da177e4 | 21 | |
1da177e4 LT |
22 | #define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args) |
23 | #define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args) | |
24 | ||
25 | ||
26 | /* Info for the block device */ | |
27 | struct block2mtd_dev { | |
28 | struct list_head list; | |
29 | struct block_device *blkdev; | |
30 | struct mtd_info mtd; | |
48b19268 | 31 | struct mutex write_mutex; |
1da177e4 LT |
32 | }; |
33 | ||
34 | ||
35 | /* Static info about the MTD, used in cleanup_module */ | |
36 | static LIST_HEAD(blkmtd_device_list); | |
37 | ||
38 | ||
6fe6900e | 39 | static struct page *page_read(struct address_space *mapping, int index) |
1da177e4 | 40 | { |
6fe6900e | 41 | return read_mapping_page(mapping, index, NULL); |
1da177e4 LT |
42 | } |
43 | ||
1da177e4 LT |
44 | /* erase a specified part of the device */ |
45 | static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len) | |
46 | { | |
47 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
48 | struct page *page; | |
49 | int index = to >> PAGE_SHIFT; // page index | |
50 | int pages = len >> PAGE_SHIFT; | |
51 | u_long *p; | |
52 | u_long *max; | |
53 | ||
54 | while (pages) { | |
21d31f1f | 55 | page = page_read(mapping, index); |
1da177e4 LT |
56 | if (!page) |
57 | return -ENOMEM; | |
58 | if (IS_ERR(page)) | |
59 | return PTR_ERR(page); | |
60 | ||
0ffb74cc JE |
61 | max = page_address(page) + PAGE_SIZE; |
62 | for (p=page_address(page); p<max; p++) | |
1da177e4 LT |
63 | if (*p != -1UL) { |
64 | lock_page(page); | |
65 | memset(page_address(page), 0xff, PAGE_SIZE); | |
66 | set_page_dirty(page); | |
67 | unlock_page(page); | |
68 | break; | |
69 | } | |
70 | ||
71 | page_cache_release(page); | |
72 | pages--; | |
73 | index++; | |
74 | } | |
75 | return 0; | |
76 | } | |
77 | static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr) | |
78 | { | |
79 | struct block2mtd_dev *dev = mtd->priv; | |
80 | size_t from = instr->addr; | |
81 | size_t len = instr->len; | |
82 | int err; | |
83 | ||
84 | instr->state = MTD_ERASING; | |
48b19268 | 85 | mutex_lock(&dev->write_mutex); |
1da177e4 | 86 | err = _block2mtd_erase(dev, from, len); |
48b19268 | 87 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
88 | if (err) { |
89 | ERROR("erase failed err = %d", err); | |
90 | instr->state = MTD_ERASE_FAILED; | |
91 | } else | |
92 | instr->state = MTD_ERASE_DONE; | |
93 | ||
94 | instr->state = MTD_ERASE_DONE; | |
95 | mtd_erase_callback(instr); | |
96 | return err; | |
97 | } | |
98 | ||
99 | ||
100 | static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len, | |
101 | size_t *retlen, u_char *buf) | |
102 | { | |
103 | struct block2mtd_dev *dev = mtd->priv; | |
104 | struct page *page; | |
105 | int index = from >> PAGE_SHIFT; | |
711c11b7 | 106 | int offset = from & (PAGE_SIZE-1); |
1da177e4 LT |
107 | int cpylen; |
108 | ||
109 | if (from > mtd->size) | |
110 | return -EINVAL; | |
111 | if (from + len > mtd->size) | |
112 | len = mtd->size - from; | |
113 | ||
114 | if (retlen) | |
115 | *retlen = 0; | |
116 | ||
117 | while (len) { | |
118 | if ((offset + len) > PAGE_SIZE) | |
119 | cpylen = PAGE_SIZE - offset; // multiple pages | |
120 | else | |
121 | cpylen = len; // this page | |
122 | len = len - cpylen; | |
123 | ||
21d31f1f | 124 | page = page_read(dev->blkdev->bd_inode->i_mapping, index); |
1da177e4 LT |
125 | if (!page) |
126 | return -ENOMEM; | |
127 | if (IS_ERR(page)) | |
128 | return PTR_ERR(page); | |
129 | ||
130 | memcpy(buf, page_address(page) + offset, cpylen); | |
131 | page_cache_release(page); | |
132 | ||
133 | if (retlen) | |
134 | *retlen += cpylen; | |
135 | buf += cpylen; | |
136 | offset = 0; | |
137 | index++; | |
138 | } | |
139 | return 0; | |
140 | } | |
141 | ||
142 | ||
143 | /* write data to the underlying device */ | |
144 | static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf, | |
145 | loff_t to, size_t len, size_t *retlen) | |
146 | { | |
147 | struct page *page; | |
148 | struct address_space *mapping = dev->blkdev->bd_inode->i_mapping; | |
149 | int index = to >> PAGE_SHIFT; // page index | |
150 | int offset = to & ~PAGE_MASK; // page offset | |
151 | int cpylen; | |
152 | ||
153 | if (retlen) | |
154 | *retlen = 0; | |
155 | while (len) { | |
e5580fbe | 156 | if ((offset+len) > PAGE_SIZE) |
1da177e4 LT |
157 | cpylen = PAGE_SIZE - offset; // multiple pages |
158 | else | |
159 | cpylen = len; // this page | |
160 | len = len - cpylen; | |
161 | ||
21d31f1f | 162 | page = page_read(mapping, index); |
1da177e4 LT |
163 | if (!page) |
164 | return -ENOMEM; | |
165 | if (IS_ERR(page)) | |
166 | return PTR_ERR(page); | |
167 | ||
168 | if (memcmp(page_address(page)+offset, buf, cpylen)) { | |
169 | lock_page(page); | |
170 | memcpy(page_address(page) + offset, buf, cpylen); | |
171 | set_page_dirty(page); | |
172 | unlock_page(page); | |
173 | } | |
174 | page_cache_release(page); | |
175 | ||
176 | if (retlen) | |
177 | *retlen += cpylen; | |
178 | ||
179 | buf += cpylen; | |
180 | offset = 0; | |
181 | index++; | |
182 | } | |
183 | return 0; | |
184 | } | |
c4e7fb31 VH |
185 | |
186 | ||
1da177e4 LT |
187 | static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len, |
188 | size_t *retlen, const u_char *buf) | |
189 | { | |
190 | struct block2mtd_dev *dev = mtd->priv; | |
191 | int err; | |
192 | ||
193 | if (!len) | |
194 | return 0; | |
195 | if (to >= mtd->size) | |
196 | return -ENOSPC; | |
197 | if (to + len > mtd->size) | |
198 | len = mtd->size - to; | |
199 | ||
48b19268 | 200 | mutex_lock(&dev->write_mutex); |
1da177e4 | 201 | err = _block2mtd_write(dev, buf, to, len, retlen); |
48b19268 | 202 | mutex_unlock(&dev->write_mutex); |
1da177e4 LT |
203 | if (err > 0) |
204 | err = 0; | |
205 | return err; | |
206 | } | |
207 | ||
208 | ||
209 | /* sync the device - wait until the write queue is empty */ | |
210 | static void block2mtd_sync(struct mtd_info *mtd) | |
211 | { | |
212 | struct block2mtd_dev *dev = mtd->priv; | |
213 | sync_blockdev(dev->blkdev); | |
214 | return; | |
215 | } | |
216 | ||
217 | ||
218 | static void block2mtd_free_device(struct block2mtd_dev *dev) | |
219 | { | |
220 | if (!dev) | |
221 | return; | |
222 | ||
223 | kfree(dev->mtd.name); | |
224 | ||
225 | if (dev->blkdev) { | |
fc0ecff6 AM |
226 | invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, |
227 | 0, -1); | |
30c40d2c | 228 | close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE); |
1da177e4 LT |
229 | } |
230 | ||
231 | kfree(dev); | |
232 | } | |
233 | ||
234 | ||
235 | /* FIXME: ensure that mtd->size % erase_size == 0 */ | |
236 | static struct block2mtd_dev *add_device(char *devname, int erase_size) | |
237 | { | |
238 | struct block_device *bdev; | |
239 | struct block2mtd_dev *dev; | |
eadcf0d7 | 240 | char *name; |
1da177e4 LT |
241 | |
242 | if (!devname) | |
243 | return NULL; | |
244 | ||
95b93a0c | 245 | dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL); |
1da177e4 LT |
246 | if (!dev) |
247 | return NULL; | |
1da177e4 LT |
248 | |
249 | /* Get a handle on the device */ | |
30c40d2c | 250 | bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, NULL); |
c4e7fb31 VH |
251 | #ifndef MODULE |
252 | if (IS_ERR(bdev)) { | |
253 | ||
254 | /* We might not have rootfs mounted at this point. Try | |
255 | to resolve the device name by other means. */ | |
256 | ||
8870530a JE |
257 | dev_t devt = name_to_dev_t(devname); |
258 | if (devt) { | |
259 | bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ); | |
c4e7fb31 VH |
260 | } |
261 | } | |
262 | #endif | |
263 | ||
1da177e4 LT |
264 | if (IS_ERR(bdev)) { |
265 | ERROR("error: cannot open device %s", devname); | |
266 | goto devinit_err; | |
267 | } | |
268 | dev->blkdev = bdev; | |
269 | ||
270 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
271 | ERROR("attempting to use an MTD device as a block device"); | |
272 | goto devinit_err; | |
273 | } | |
274 | ||
48b19268 | 275 | mutex_init(&dev->write_mutex); |
1da177e4 LT |
276 | |
277 | /* Setup the MTD structure */ | |
278 | /* make the name contain the block device in */ | |
eadcf0d7 | 279 | name = kmalloc(sizeof("block2mtd: ") + strlen(devname) + 1, |
1da177e4 | 280 | GFP_KERNEL); |
eadcf0d7 | 281 | if (!name) |
1da177e4 LT |
282 | goto devinit_err; |
283 | ||
eadcf0d7 GKH |
284 | sprintf(name, "block2mtd: %s", devname); |
285 | dev->mtd.name = name; | |
1da177e4 LT |
286 | |
287 | dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK; | |
288 | dev->mtd.erasesize = erase_size; | |
17ffc7ba | 289 | dev->mtd.writesize = 1; |
21c8db9e | 290 | dev->mtd.type = MTD_RAM; |
1da177e4 LT |
291 | dev->mtd.flags = MTD_CAP_RAM; |
292 | dev->mtd.erase = block2mtd_erase; | |
293 | dev->mtd.write = block2mtd_write; | |
294 | dev->mtd.writev = default_mtd_writev; | |
295 | dev->mtd.sync = block2mtd_sync; | |
296 | dev->mtd.read = block2mtd_read; | |
1da177e4 LT |
297 | dev->mtd.priv = dev; |
298 | dev->mtd.owner = THIS_MODULE; | |
299 | ||
300 | if (add_mtd_device(&dev->mtd)) { | |
301 | /* Device didnt get added, so free the entry */ | |
302 | goto devinit_err; | |
303 | } | |
304 | list_add(&dev->list, &blkmtd_device_list); | |
305 | INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index, | |
0bc88c59 | 306 | dev->mtd.name + strlen("block2mtd: "), |
1da177e4 LT |
307 | dev->mtd.erasesize >> 10, dev->mtd.erasesize); |
308 | return dev; | |
309 | ||
310 | devinit_err: | |
311 | block2mtd_free_device(dev); | |
312 | return NULL; | |
313 | } | |
314 | ||
315 | ||
954c2422 JE |
316 | /* This function works similar to reguler strtoul. In addition, it |
317 | * allows some suffixes for a more human-readable number format: | |
318 | * ki, Ki, kiB, KiB - multiply result with 1024 | |
319 | * Mi, MiB - multiply result with 1024^2 | |
320 | * Gi, GiB - multiply result with 1024^3 | |
321 | */ | |
1da177e4 LT |
322 | static int ustrtoul(const char *cp, char **endp, unsigned int base) |
323 | { | |
324 | unsigned long result = simple_strtoul(cp, endp, base); | |
325 | switch (**endp) { | |
326 | case 'G' : | |
327 | result *= 1024; | |
328 | case 'M': | |
329 | result *= 1024; | |
954c2422 | 330 | case 'K': |
1da177e4 LT |
331 | case 'k': |
332 | result *= 1024; | |
333 | /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ | |
954c2422 JE |
334 | if ((*endp)[1] == 'i') { |
335 | if ((*endp)[2] == 'B') | |
336 | (*endp) += 3; | |
337 | else | |
338 | (*endp) += 2; | |
339 | } | |
1da177e4 LT |
340 | } |
341 | return result; | |
342 | } | |
343 | ||
344 | ||
cc71229f | 345 | static int parse_num(size_t *num, const char *token) |
1da177e4 LT |
346 | { |
347 | char *endp; | |
cc71229f | 348 | size_t n; |
1da177e4 | 349 | |
cc71229f | 350 | n = (size_t) ustrtoul(token, &endp, 0); |
1da177e4 LT |
351 | if (*endp) |
352 | return -EINVAL; | |
353 | ||
cc71229f | 354 | *num = n; |
1da177e4 LT |
355 | return 0; |
356 | } | |
357 | ||
358 | ||
1da177e4 LT |
359 | static inline void kill_final_newline(char *str) |
360 | { | |
361 | char *newline = strrchr(str, '\n'); | |
362 | if (newline && !newline[1]) | |
363 | *newline = 0; | |
364 | } | |
365 | ||
366 | ||
0bc88c59 SC |
367 | #define parse_err(fmt, args...) do { \ |
368 | ERROR(fmt, ## args); \ | |
369 | return 0; \ | |
1da177e4 LT |
370 | } while (0) |
371 | ||
c4e7fb31 VH |
372 | #ifndef MODULE |
373 | static int block2mtd_init_called = 0; | |
4839f048 | 374 | static char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */ |
c4e7fb31 VH |
375 | #endif |
376 | ||
377 | ||
378 | static int block2mtd_setup2(const char *val) | |
1da177e4 | 379 | { |
c4e7fb31 | 380 | char buf[80 + 12]; /* 80 for device, 12 for erase size */ |
a6550e57 | 381 | char *str = buf; |
1da177e4 LT |
382 | char *token[2]; |
383 | char *name; | |
cc71229f | 384 | size_t erase_size = PAGE_SIZE; |
1da177e4 LT |
385 | int i, ret; |
386 | ||
387 | if (strnlen(val, sizeof(buf)) >= sizeof(buf)) | |
388 | parse_err("parameter too long"); | |
389 | ||
390 | strcpy(str, val); | |
391 | kill_final_newline(str); | |
392 | ||
a6550e57 | 393 | for (i = 0; i < 2; i++) |
1da177e4 LT |
394 | token[i] = strsep(&str, ","); |
395 | ||
396 | if (str) | |
397 | parse_err("too many arguments"); | |
398 | ||
399 | if (!token[0]) | |
400 | parse_err("no argument"); | |
401 | ||
c4e7fb31 VH |
402 | name = token[0]; |
403 | if (strlen(name) + 1 > 80) | |
404 | parse_err("device name too long"); | |
1da177e4 LT |
405 | |
406 | if (token[1]) { | |
cc71229f | 407 | ret = parse_num(&erase_size, token[1]); |
a6550e57 | 408 | if (ret) { |
1da177e4 | 409 | parse_err("illegal erase size"); |
a6550e57 | 410 | } |
1da177e4 LT |
411 | } |
412 | ||
413 | add_device(name, erase_size); | |
414 | ||
415 | return 0; | |
416 | } | |
417 | ||
418 | ||
c4e7fb31 VH |
419 | static int block2mtd_setup(const char *val, struct kernel_param *kp) |
420 | { | |
421 | #ifdef MODULE | |
422 | return block2mtd_setup2(val); | |
423 | #else | |
424 | /* If more parameters are later passed in via | |
425 | /sys/module/block2mtd/parameters/block2mtd | |
426 | and block2mtd_init() has already been called, | |
427 | we can parse the argument now. */ | |
428 | ||
429 | if (block2mtd_init_called) | |
430 | return block2mtd_setup2(val); | |
431 | ||
432 | /* During early boot stage, we only save the parameters | |
433 | here. We must parse them later: if the param passed | |
434 | from kernel boot command line, block2mtd_setup() is | |
435 | called so early that it is not possible to resolve | |
436 | the device (even kmalloc() fails). Deter that work to | |
437 | block2mtd_setup2(). */ | |
438 | ||
439 | strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline)); | |
440 | ||
441 | return 0; | |
442 | #endif | |
443 | } | |
444 | ||
445 | ||
1da177e4 LT |
446 | module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200); |
447 | MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\""); | |
448 | ||
449 | static int __init block2mtd_init(void) | |
450 | { | |
c4e7fb31 | 451 | int ret = 0; |
c4e7fb31 VH |
452 | |
453 | #ifndef MODULE | |
454 | if (strlen(block2mtd_paramline)) | |
455 | ret = block2mtd_setup2(block2mtd_paramline); | |
456 | block2mtd_init_called = 1; | |
457 | #endif | |
458 | ||
459 | return ret; | |
1da177e4 LT |
460 | } |
461 | ||
462 | ||
463 | static void __devexit block2mtd_exit(void) | |
464 | { | |
465 | struct list_head *pos, *next; | |
466 | ||
467 | /* Remove the MTD devices */ | |
468 | list_for_each_safe(pos, next, &blkmtd_device_list) { | |
469 | struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list); | |
470 | block2mtd_sync(&dev->mtd); | |
471 | del_mtd_device(&dev->mtd); | |
472 | INFO("mtd%d: [%s] removed", dev->mtd.index, | |
0bc88c59 | 473 | dev->mtd.name + strlen("block2mtd: ")); |
1da177e4 LT |
474 | list_del(&dev->list); |
475 | block2mtd_free_device(dev); | |
476 | } | |
477 | } | |
478 | ||
479 | ||
480 | module_init(block2mtd_init); | |
481 | module_exit(block2mtd_exit); | |
482 | ||
483 | MODULE_LICENSE("GPL"); | |
2b54aaef | 484 | MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>"); |
1da177e4 | 485 | MODULE_DESCRIPTION("Emulate an MTD using a block device"); |