Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * $Id: blkmtd.c,v 1.24 2004/11/16 18:29:01 dwmw2 Exp $ |
| 3 | * |
| 4 | * blkmtd.c - use a block device as a fake MTD |
| 5 | * |
| 6 | * Author: Simon Evans <spse@secret.org.uk> |
| 7 | * |
| 8 | * Copyright (C) 2001,2002 Simon Evans |
| 9 | * |
| 10 | * Licence: GPL |
| 11 | * |
| 12 | * How it works: |
| 13 | * The driver uses raw/io to read/write the device and the page |
| 14 | * cache to cache access. Writes update the page cache with the |
| 15 | * new data and mark it dirty and add the page into a BIO which |
| 16 | * is then written out. |
| 17 | * |
| 18 | * It can be loaded Read-Only to prevent erases and writes to the |
| 19 | * medium. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/config.h> |
| 24 | #include <linux/module.h> |
| 25 | #include <linux/fs.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/bio.h> |
| 28 | #include <linux/pagemap.h> |
| 29 | #include <linux/list.h> |
| 30 | #include <linux/init.h> |
| 31 | #include <linux/mtd/mtd.h> |
| 32 | |
| 33 | |
| 34 | #define err(format, arg...) printk(KERN_ERR "blkmtd: " format "\n" , ## arg) |
| 35 | #define info(format, arg...) printk(KERN_INFO "blkmtd: " format "\n" , ## arg) |
| 36 | #define warn(format, arg...) printk(KERN_WARNING "blkmtd: " format "\n" , ## arg) |
| 37 | #define crit(format, arg...) printk(KERN_CRIT "blkmtd: " format "\n" , ## arg) |
| 38 | |
| 39 | |
| 40 | /* Default erase size in K, always make it a multiple of PAGE_SIZE */ |
| 41 | #define CONFIG_MTD_BLKDEV_ERASESIZE (128 << 10) /* 128KiB */ |
| 42 | #define VERSION "$Revision: 1.24 $" |
| 43 | |
| 44 | /* Info for the block device */ |
| 45 | struct blkmtd_dev { |
| 46 | struct list_head list; |
| 47 | struct block_device *blkdev; |
| 48 | struct mtd_info mtd_info; |
| 49 | struct semaphore wrbuf_mutex; |
| 50 | }; |
| 51 | |
| 52 | |
| 53 | /* Static info about the MTD, used in cleanup_module */ |
| 54 | static LIST_HEAD(blkmtd_device_list); |
| 55 | |
| 56 | |
| 57 | static void blkmtd_sync(struct mtd_info *mtd); |
| 58 | |
| 59 | #define MAX_DEVICES 4 |
| 60 | |
| 61 | /* Module parameters passed by insmod/modprobe */ |
| 62 | static char *device[MAX_DEVICES]; /* the block device to use */ |
| 63 | static int erasesz[MAX_DEVICES]; /* optional default erase size */ |
| 64 | static int ro[MAX_DEVICES]; /* optional read only flag */ |
| 65 | static int sync; |
| 66 | |
| 67 | |
| 68 | MODULE_LICENSE("GPL"); |
| 69 | MODULE_AUTHOR("Simon Evans <spse@secret.org.uk>"); |
| 70 | MODULE_DESCRIPTION("Emulate an MTD using a block device"); |
| 71 | module_param_array(device, charp, NULL, 0); |
| 72 | MODULE_PARM_DESC(device, "block device to use"); |
| 73 | module_param_array(erasesz, int, NULL, 0); |
| 74 | MODULE_PARM_DESC(erasesz, "optional erase size to use in KiB. eg 4=4KiB."); |
| 75 | module_param_array(ro, bool, NULL, 0); |
| 76 | MODULE_PARM_DESC(ro, "1=Read only, writes and erases cause errors"); |
| 77 | module_param(sync, bool, 0); |
| 78 | MODULE_PARM_DESC(sync, "1=Synchronous writes"); |
| 79 | |
| 80 | |
| 81 | /* completion handler for BIO reads */ |
| 82 | static int bi_read_complete(struct bio *bio, unsigned int bytes_done, int error) |
| 83 | { |
| 84 | if (bio->bi_size) |
| 85 | return 1; |
| 86 | |
| 87 | complete((struct completion*)bio->bi_private); |
| 88 | return 0; |
| 89 | } |
| 90 | |
| 91 | |
| 92 | /* completion handler for BIO writes */ |
| 93 | static int bi_write_complete(struct bio *bio, unsigned int bytes_done, int error) |
| 94 | { |
| 95 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 96 | struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; |
| 97 | |
| 98 | if (bio->bi_size) |
| 99 | return 1; |
| 100 | |
| 101 | if(!uptodate) |
| 102 | err("bi_write_complete: not uptodate\n"); |
| 103 | |
| 104 | do { |
| 105 | struct page *page = bvec->bv_page; |
| 106 | DEBUG(3, "Cleaning up page %ld\n", page->index); |
| 107 | if (--bvec >= bio->bi_io_vec) |
| 108 | prefetchw(&bvec->bv_page->flags); |
| 109 | |
| 110 | if (uptodate) { |
| 111 | SetPageUptodate(page); |
| 112 | } else { |
| 113 | ClearPageUptodate(page); |
| 114 | SetPageError(page); |
| 115 | } |
| 116 | ClearPageDirty(page); |
| 117 | unlock_page(page); |
| 118 | page_cache_release(page); |
| 119 | } while (bvec >= bio->bi_io_vec); |
| 120 | |
| 121 | complete((struct completion*)bio->bi_private); |
| 122 | return 0; |
| 123 | } |
| 124 | |
| 125 | |
| 126 | /* read one page from the block device */ |
| 127 | static int blkmtd_readpage(struct blkmtd_dev *dev, struct page *page) |
| 128 | { |
| 129 | struct bio *bio; |
| 130 | struct completion event; |
| 131 | int err = -ENOMEM; |
| 132 | |
| 133 | if(PageUptodate(page)) { |
| 134 | DEBUG(2, "blkmtd: readpage page %ld is already upto date\n", page->index); |
| 135 | unlock_page(page); |
| 136 | return 0; |
| 137 | } |
| 138 | |
| 139 | ClearPageUptodate(page); |
| 140 | ClearPageError(page); |
| 141 | |
| 142 | bio = bio_alloc(GFP_KERNEL, 1); |
| 143 | if(bio) { |
| 144 | init_completion(&event); |
| 145 | bio->bi_bdev = dev->blkdev; |
| 146 | bio->bi_sector = page->index << (PAGE_SHIFT-9); |
| 147 | bio->bi_private = &event; |
| 148 | bio->bi_end_io = bi_read_complete; |
| 149 | if(bio_add_page(bio, page, PAGE_SIZE, 0) == PAGE_SIZE) { |
| 150 | submit_bio(READ_SYNC, bio); |
| 151 | wait_for_completion(&event); |
| 152 | err = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : -EIO; |
| 153 | bio_put(bio); |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | if(err) |
| 158 | SetPageError(page); |
| 159 | else |
| 160 | SetPageUptodate(page); |
| 161 | flush_dcache_page(page); |
| 162 | unlock_page(page); |
| 163 | return err; |
| 164 | } |
| 165 | |
| 166 | |
| 167 | /* write out the current BIO and wait for it to finish */ |
| 168 | static int blkmtd_write_out(struct bio *bio) |
| 169 | { |
| 170 | struct completion event; |
| 171 | int err; |
| 172 | |
| 173 | if(!bio->bi_vcnt) { |
| 174 | bio_put(bio); |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | init_completion(&event); |
| 179 | bio->bi_private = &event; |
| 180 | bio->bi_end_io = bi_write_complete; |
| 181 | submit_bio(WRITE_SYNC, bio); |
| 182 | wait_for_completion(&event); |
| 183 | DEBUG(3, "submit_bio completed, bi_vcnt = %d\n", bio->bi_vcnt); |
| 184 | err = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : -EIO; |
| 185 | bio_put(bio); |
| 186 | return err; |
| 187 | } |
| 188 | |
| 189 | |
| 190 | /** |
| 191 | * blkmtd_add_page - add a page to the current BIO |
| 192 | * @bio: bio to add to (NULL to alloc initial bio) |
| 193 | * @blkdev: block device |
| 194 | * @page: page to add |
| 195 | * @pagecnt: pages left to add |
| 196 | * |
| 197 | * Adds a page to the current bio, allocating it if necessary. If it cannot be |
| 198 | * added, the current bio is written out and a new one is allocated. Returns |
| 199 | * the new bio to add or NULL on error |
| 200 | */ |
| 201 | static struct bio *blkmtd_add_page(struct bio *bio, struct block_device *blkdev, |
| 202 | struct page *page, int pagecnt) |
| 203 | { |
| 204 | |
| 205 | retry: |
| 206 | if(!bio) { |
| 207 | bio = bio_alloc(GFP_KERNEL, pagecnt); |
| 208 | if(!bio) |
| 209 | return NULL; |
| 210 | bio->bi_sector = page->index << (PAGE_SHIFT-9); |
| 211 | bio->bi_bdev = blkdev; |
| 212 | } |
| 213 | |
| 214 | if(bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) { |
| 215 | blkmtd_write_out(bio); |
| 216 | bio = NULL; |
| 217 | goto retry; |
| 218 | } |
| 219 | return bio; |
| 220 | } |
| 221 | |
| 222 | |
| 223 | /** |
| 224 | * write_pages - write block of data to device via the page cache |
| 225 | * @dev: device to write to |
| 226 | * @buf: data source or NULL if erase (output is set to 0xff) |
| 227 | * @to: offset into output device |
| 228 | * @len: amount to data to write |
| 229 | * @retlen: amount of data written |
| 230 | * |
| 231 | * Grab pages from the page cache and fill them with the source data. |
| 232 | * Non page aligned start and end result in a readin of the page and |
| 233 | * part of the page being modified. Pages are added to the bio and then written |
| 234 | * out. |
| 235 | */ |
| 236 | static int write_pages(struct blkmtd_dev *dev, const u_char *buf, loff_t to, |
| 237 | size_t len, size_t *retlen) |
| 238 | { |
| 239 | int pagenr, offset; |
| 240 | size_t start_len = 0, end_len; |
| 241 | int pagecnt = 0; |
| 242 | int err = 0; |
| 243 | struct bio *bio = NULL; |
| 244 | size_t thislen = 0; |
| 245 | |
| 246 | pagenr = to >> PAGE_SHIFT; |
| 247 | offset = to & ~PAGE_MASK; |
| 248 | |
| 249 | DEBUG(2, "blkmtd: write_pages: buf = %p to = %ld len = %zd pagenr = %d offset = %d\n", |
| 250 | buf, (long)to, len, pagenr, offset); |
| 251 | |
| 252 | /* see if we have to do a partial write at the start */ |
| 253 | if(offset) { |
| 254 | start_len = ((offset + len) > PAGE_SIZE) ? PAGE_SIZE - offset : len; |
| 255 | len -= start_len; |
| 256 | } |
| 257 | |
| 258 | /* calculate the length of the other two regions */ |
| 259 | end_len = len & ~PAGE_MASK; |
| 260 | len -= end_len; |
| 261 | |
| 262 | if(start_len) |
| 263 | pagecnt++; |
| 264 | |
| 265 | if(len) |
| 266 | pagecnt += len >> PAGE_SHIFT; |
| 267 | |
| 268 | if(end_len) |
| 269 | pagecnt++; |
| 270 | |
| 271 | down(&dev->wrbuf_mutex); |
| 272 | |
| 273 | DEBUG(3, "blkmtd: write: start_len = %zd len = %zd end_len = %zd pagecnt = %d\n", |
| 274 | start_len, len, end_len, pagecnt); |
| 275 | |
| 276 | if(start_len) { |
| 277 | /* do partial start region */ |
| 278 | struct page *page; |
| 279 | |
| 280 | DEBUG(3, "blkmtd: write: doing partial start, page = %d len = %zd offset = %d\n", |
| 281 | pagenr, start_len, offset); |
| 282 | |
| 283 | BUG_ON(!buf); |
| 284 | page = read_cache_page(dev->blkdev->bd_inode->i_mapping, pagenr, (filler_t *)blkmtd_readpage, dev); |
| 285 | lock_page(page); |
| 286 | if(PageDirty(page)) { |
| 287 | err("to = %lld start_len = %zd len = %zd end_len = %zd pagenr = %d\n", |
| 288 | to, start_len, len, end_len, pagenr); |
| 289 | BUG(); |
| 290 | } |
| 291 | memcpy(page_address(page)+offset, buf, start_len); |
| 292 | SetPageDirty(page); |
| 293 | SetPageUptodate(page); |
| 294 | buf += start_len; |
| 295 | thislen = start_len; |
| 296 | bio = blkmtd_add_page(bio, dev->blkdev, page, pagecnt); |
| 297 | if(!bio) { |
| 298 | err = -ENOMEM; |
| 299 | err("bio_add_page failed\n"); |
| 300 | goto write_err; |
| 301 | } |
| 302 | pagecnt--; |
| 303 | pagenr++; |
| 304 | } |
| 305 | |
| 306 | /* Now do the main loop to a page aligned, n page sized output */ |
| 307 | if(len) { |
| 308 | int pagesc = len >> PAGE_SHIFT; |
| 309 | DEBUG(3, "blkmtd: write: whole pages start = %d, count = %d\n", |
| 310 | pagenr, pagesc); |
| 311 | while(pagesc) { |
| 312 | struct page *page; |
| 313 | |
| 314 | /* see if page is in the page cache */ |
| 315 | DEBUG(3, "blkmtd: write: grabbing page %d from page cache\n", pagenr); |
| 316 | page = grab_cache_page(dev->blkdev->bd_inode->i_mapping, pagenr); |
| 317 | if(PageDirty(page)) { |
| 318 | BUG(); |
| 319 | } |
| 320 | if(!page) { |
| 321 | warn("write: cannot grab cache page %d", pagenr); |
| 322 | err = -ENOMEM; |
| 323 | goto write_err; |
| 324 | } |
| 325 | if(!buf) { |
| 326 | memset(page_address(page), 0xff, PAGE_SIZE); |
| 327 | } else { |
| 328 | memcpy(page_address(page), buf, PAGE_SIZE); |
| 329 | buf += PAGE_SIZE; |
| 330 | } |
| 331 | bio = blkmtd_add_page(bio, dev->blkdev, page, pagecnt); |
| 332 | if(!bio) { |
| 333 | err = -ENOMEM; |
| 334 | err("bio_add_page failed\n"); |
| 335 | goto write_err; |
| 336 | } |
| 337 | pagenr++; |
| 338 | pagecnt--; |
| 339 | SetPageDirty(page); |
| 340 | SetPageUptodate(page); |
| 341 | pagesc--; |
| 342 | thislen += PAGE_SIZE; |
| 343 | } |
| 344 | } |
| 345 | |
| 346 | if(end_len) { |
| 347 | /* do the third region */ |
| 348 | struct page *page; |
| 349 | DEBUG(3, "blkmtd: write: doing partial end, page = %d len = %zd\n", |
| 350 | pagenr, end_len); |
| 351 | BUG_ON(!buf); |
| 352 | page = read_cache_page(dev->blkdev->bd_inode->i_mapping, pagenr, (filler_t *)blkmtd_readpage, dev); |
| 353 | lock_page(page); |
| 354 | if(PageDirty(page)) { |
| 355 | err("to = %lld start_len = %zd len = %zd end_len = %zd pagenr = %d\n", |
| 356 | to, start_len, len, end_len, pagenr); |
| 357 | BUG(); |
| 358 | } |
| 359 | memcpy(page_address(page), buf, end_len); |
| 360 | SetPageDirty(page); |
| 361 | SetPageUptodate(page); |
| 362 | DEBUG(3, "blkmtd: write: writing out partial end\n"); |
| 363 | thislen += end_len; |
| 364 | bio = blkmtd_add_page(bio, dev->blkdev, page, pagecnt); |
| 365 | if(!bio) { |
| 366 | err = -ENOMEM; |
| 367 | err("bio_add_page failed\n"); |
| 368 | goto write_err; |
| 369 | } |
| 370 | pagenr++; |
| 371 | } |
| 372 | |
| 373 | DEBUG(3, "blkmtd: write: got %d vectors to write\n", bio->bi_vcnt); |
| 374 | write_err: |
| 375 | if(bio) |
| 376 | blkmtd_write_out(bio); |
| 377 | |
| 378 | DEBUG(2, "blkmtd: write: end, retlen = %zd, err = %d\n", *retlen, err); |
| 379 | up(&dev->wrbuf_mutex); |
| 380 | |
| 381 | if(retlen) |
| 382 | *retlen = thislen; |
| 383 | return err; |
| 384 | } |
| 385 | |
| 386 | |
| 387 | /* erase a specified part of the device */ |
| 388 | static int blkmtd_erase(struct mtd_info *mtd, struct erase_info *instr) |
| 389 | { |
| 390 | struct blkmtd_dev *dev = mtd->priv; |
| 391 | struct mtd_erase_region_info *einfo = mtd->eraseregions; |
| 392 | int numregions = mtd->numeraseregions; |
| 393 | size_t from; |
| 394 | u_long len; |
| 395 | int err = -EIO; |
| 396 | size_t retlen; |
| 397 | |
| 398 | instr->state = MTD_ERASING; |
| 399 | from = instr->addr; |
| 400 | len = instr->len; |
| 401 | |
| 402 | /* check erase region has valid start and length */ |
| 403 | DEBUG(2, "blkmtd: erase: dev = `%s' from = 0x%zx len = 0x%lx\n", |
| 404 | mtd->name+9, from, len); |
| 405 | while(numregions) { |
| 406 | DEBUG(3, "blkmtd: checking erase region = 0x%08X size = 0x%X num = 0x%x\n", |
| 407 | einfo->offset, einfo->erasesize, einfo->numblocks); |
| 408 | if(from >= einfo->offset |
| 409 | && from < einfo->offset + (einfo->erasesize * einfo->numblocks)) { |
| 410 | if(len == einfo->erasesize |
| 411 | && ( (from - einfo->offset) % einfo->erasesize == 0)) |
| 412 | break; |
| 413 | } |
| 414 | numregions--; |
| 415 | einfo++; |
| 416 | } |
| 417 | |
| 418 | if(!numregions) { |
| 419 | /* Not a valid erase block */ |
| 420 | err("erase: invalid erase request 0x%lX @ 0x%08zX", len, from); |
| 421 | instr->state = MTD_ERASE_FAILED; |
| 422 | err = -EIO; |
| 423 | } |
| 424 | |
| 425 | if(instr->state != MTD_ERASE_FAILED) { |
| 426 | /* do the erase */ |
| 427 | DEBUG(3, "Doing erase from = %zd len = %ld\n", from, len); |
| 428 | err = write_pages(dev, NULL, from, len, &retlen); |
| 429 | if(err || retlen != len) { |
| 430 | err("erase failed err = %d", err); |
| 431 | instr->state = MTD_ERASE_FAILED; |
| 432 | } else { |
| 433 | instr->state = MTD_ERASE_DONE; |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | DEBUG(3, "blkmtd: erase: checking callback\n"); |
| 438 | mtd_erase_callback(instr); |
| 439 | DEBUG(2, "blkmtd: erase: finished (err = %d)\n", err); |
| 440 | return err; |
| 441 | } |
| 442 | |
| 443 | |
| 444 | /* read a range of the data via the page cache */ |
| 445 | static int blkmtd_read(struct mtd_info *mtd, loff_t from, size_t len, |
| 446 | size_t *retlen, u_char *buf) |
| 447 | { |
| 448 | struct blkmtd_dev *dev = mtd->priv; |
| 449 | int err = 0; |
| 450 | int offset; |
| 451 | int pagenr, pages; |
| 452 | size_t thislen = 0; |
| 453 | |
| 454 | DEBUG(2, "blkmtd: read: dev = `%s' from = %lld len = %zd buf = %p\n", |
| 455 | mtd->name+9, from, len, buf); |
| 456 | |
| 457 | if(from > mtd->size) |
| 458 | return -EINVAL; |
| 459 | if(from + len > mtd->size) |
| 460 | len = mtd->size - from; |
| 461 | |
| 462 | pagenr = from >> PAGE_SHIFT; |
| 463 | offset = from - (pagenr << PAGE_SHIFT); |
| 464 | |
| 465 | pages = (offset+len+PAGE_SIZE-1) >> PAGE_SHIFT; |
| 466 | DEBUG(3, "blkmtd: read: pagenr = %d offset = %d, pages = %d\n", |
| 467 | pagenr, offset, pages); |
| 468 | |
| 469 | while(pages) { |
| 470 | struct page *page; |
| 471 | int cpylen; |
| 472 | |
| 473 | DEBUG(3, "blkmtd: read: looking for page: %d\n", pagenr); |
| 474 | page = read_cache_page(dev->blkdev->bd_inode->i_mapping, pagenr, (filler_t *)blkmtd_readpage, dev); |
| 475 | if(IS_ERR(page)) { |
| 476 | err = -EIO; |
| 477 | goto readerr; |
| 478 | } |
| 479 | |
| 480 | cpylen = (PAGE_SIZE > len) ? len : PAGE_SIZE; |
| 481 | if(offset+cpylen > PAGE_SIZE) |
| 482 | cpylen = PAGE_SIZE-offset; |
| 483 | |
| 484 | memcpy(buf + thislen, page_address(page) + offset, cpylen); |
| 485 | offset = 0; |
| 486 | len -= cpylen; |
| 487 | thislen += cpylen; |
| 488 | pagenr++; |
| 489 | pages--; |
| 490 | if(!PageDirty(page)) |
| 491 | page_cache_release(page); |
| 492 | } |
| 493 | |
| 494 | readerr: |
| 495 | if(retlen) |
| 496 | *retlen = thislen; |
| 497 | DEBUG(2, "blkmtd: end read: retlen = %zd, err = %d\n", thislen, err); |
| 498 | return err; |
| 499 | } |
| 500 | |
| 501 | |
| 502 | /* write data to the underlying device */ |
| 503 | static int blkmtd_write(struct mtd_info *mtd, loff_t to, size_t len, |
| 504 | size_t *retlen, const u_char *buf) |
| 505 | { |
| 506 | struct blkmtd_dev *dev = mtd->priv; |
| 507 | int err; |
| 508 | |
| 509 | if(!len) |
| 510 | return 0; |
| 511 | |
| 512 | DEBUG(2, "blkmtd: write: dev = `%s' to = %lld len = %zd buf = %p\n", |
| 513 | mtd->name+9, to, len, buf); |
| 514 | |
| 515 | if(to >= mtd->size) { |
| 516 | return -ENOSPC; |
| 517 | } |
| 518 | |
| 519 | if(to + len > mtd->size) { |
| 520 | len = mtd->size - to; |
| 521 | } |
| 522 | |
| 523 | err = write_pages(dev, buf, to, len, retlen); |
| 524 | if(err > 0) |
| 525 | err = 0; |
| 526 | DEBUG(2, "blkmtd: write: end, err = %d\n", err); |
| 527 | return err; |
| 528 | } |
| 529 | |
| 530 | |
| 531 | /* sync the device - wait until the write queue is empty */ |
| 532 | static void blkmtd_sync(struct mtd_info *mtd) |
| 533 | { |
| 534 | /* Currently all writes are synchronous */ |
| 535 | } |
| 536 | |
| 537 | |
| 538 | static void free_device(struct blkmtd_dev *dev) |
| 539 | { |
| 540 | DEBUG(2, "blkmtd: free_device() dev = %p\n", dev); |
| 541 | if(dev) { |
| 542 | if(dev->mtd_info.eraseregions) |
| 543 | kfree(dev->mtd_info.eraseregions); |
| 544 | if(dev->mtd_info.name) |
| 545 | kfree(dev->mtd_info.name); |
| 546 | |
| 547 | if(dev->blkdev) { |
| 548 | invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping); |
| 549 | close_bdev_excl(dev->blkdev); |
| 550 | } |
| 551 | kfree(dev); |
| 552 | } |
| 553 | } |
| 554 | |
| 555 | |
| 556 | /* For a given size and initial erase size, calculate the number |
| 557 | * and size of each erase region. Goes round the loop twice, |
| 558 | * once to find out how many regions, then allocates space, |
| 559 | * then round the loop again to fill it in. |
| 560 | */ |
| 561 | static struct mtd_erase_region_info *calc_erase_regions( |
| 562 | size_t erase_size, size_t total_size, int *regions) |
| 563 | { |
| 564 | struct mtd_erase_region_info *info = NULL; |
| 565 | |
| 566 | DEBUG(2, "calc_erase_regions, es = %zd size = %zd regions = %d\n", |
| 567 | erase_size, total_size, *regions); |
| 568 | /* Make any user specified erasesize be a power of 2 |
| 569 | and at least PAGE_SIZE */ |
| 570 | if(erase_size) { |
| 571 | int es = erase_size; |
| 572 | erase_size = 1; |
| 573 | while(es != 1) { |
| 574 | es >>= 1; |
| 575 | erase_size <<= 1; |
| 576 | } |
| 577 | if(erase_size < PAGE_SIZE) |
| 578 | erase_size = PAGE_SIZE; |
| 579 | } else { |
| 580 | erase_size = CONFIG_MTD_BLKDEV_ERASESIZE; |
| 581 | } |
| 582 | |
| 583 | *regions = 0; |
| 584 | |
| 585 | do { |
| 586 | int tot_size = total_size; |
| 587 | int er_size = erase_size; |
| 588 | int count = 0, offset = 0, regcnt = 0; |
| 589 | |
| 590 | while(tot_size) { |
| 591 | count = tot_size / er_size; |
| 592 | if(count) { |
| 593 | tot_size = tot_size % er_size; |
| 594 | if(info) { |
| 595 | DEBUG(2, "adding to erase info off=%d er=%d cnt=%d\n", |
| 596 | offset, er_size, count); |
| 597 | (info+regcnt)->offset = offset; |
| 598 | (info+regcnt)->erasesize = er_size; |
| 599 | (info+regcnt)->numblocks = count; |
| 600 | (*regions)++; |
| 601 | } |
| 602 | regcnt++; |
| 603 | offset += (count * er_size); |
| 604 | } |
| 605 | while(er_size > tot_size) |
| 606 | er_size >>= 1; |
| 607 | } |
| 608 | if(info == NULL) { |
| 609 | info = kmalloc(regcnt * sizeof(struct mtd_erase_region_info), GFP_KERNEL); |
| 610 | if(!info) |
| 611 | break; |
| 612 | } |
| 613 | } while(!(*regions)); |
| 614 | DEBUG(2, "calc_erase_regions done, es = %zd size = %zd regions = %d\n", |
| 615 | erase_size, total_size, *regions); |
| 616 | return info; |
| 617 | } |
| 618 | |
| 619 | |
| 620 | extern dev_t __init name_to_dev_t(const char *line); |
| 621 | |
| 622 | static struct blkmtd_dev *add_device(char *devname, int readonly, int erase_size) |
| 623 | { |
| 624 | struct block_device *bdev; |
| 625 | int mode; |
| 626 | struct blkmtd_dev *dev; |
| 627 | |
| 628 | if(!devname) |
| 629 | return NULL; |
| 630 | |
| 631 | /* Get a handle on the device */ |
| 632 | |
| 633 | |
| 634 | #ifdef MODULE |
| 635 | mode = (readonly) ? O_RDONLY : O_RDWR; |
| 636 | bdev = open_bdev_excl(devname, mode, NULL); |
| 637 | #else |
| 638 | mode = (readonly) ? FMODE_READ : FMODE_WRITE; |
| 639 | bdev = open_by_devnum(name_to_dev_t(devname), mode); |
| 640 | #endif |
| 641 | if(IS_ERR(bdev)) { |
| 642 | err("error: cannot open device %s", devname); |
| 643 | DEBUG(2, "blkmtd: opening bdev returned %ld\n", PTR_ERR(bdev)); |
| 644 | return NULL; |
| 645 | } |
| 646 | |
| 647 | DEBUG(1, "blkmtd: found a block device major = %d, minor = %d\n", |
| 648 | MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); |
| 649 | |
| 650 | if(MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { |
| 651 | err("attempting to use an MTD device as a block device"); |
| 652 | blkdev_put(bdev); |
| 653 | return NULL; |
| 654 | } |
| 655 | |
| 656 | dev = kmalloc(sizeof(struct blkmtd_dev), GFP_KERNEL); |
| 657 | if(dev == NULL) { |
| 658 | blkdev_put(bdev); |
| 659 | return NULL; |
| 660 | } |
| 661 | |
| 662 | memset(dev, 0, sizeof(struct blkmtd_dev)); |
| 663 | dev->blkdev = bdev; |
| 664 | if(!readonly) { |
| 665 | init_MUTEX(&dev->wrbuf_mutex); |
| 666 | } |
| 667 | |
| 668 | dev->mtd_info.size = dev->blkdev->bd_inode->i_size & PAGE_MASK; |
| 669 | |
| 670 | /* Setup the MTD structure */ |
| 671 | /* make the name contain the block device in */ |
| 672 | dev->mtd_info.name = kmalloc(sizeof("blkmtd: ") + strlen(devname), GFP_KERNEL); |
| 673 | if(dev->mtd_info.name == NULL) |
| 674 | goto devinit_err; |
| 675 | |
| 676 | sprintf(dev->mtd_info.name, "blkmtd: %s", devname); |
| 677 | dev->mtd_info.eraseregions = calc_erase_regions(erase_size, dev->mtd_info.size, |
| 678 | &dev->mtd_info.numeraseregions); |
| 679 | if(dev->mtd_info.eraseregions == NULL) |
| 680 | goto devinit_err; |
| 681 | |
| 682 | dev->mtd_info.erasesize = dev->mtd_info.eraseregions->erasesize; |
| 683 | DEBUG(1, "blkmtd: init: found %d erase regions\n", |
| 684 | dev->mtd_info.numeraseregions); |
| 685 | |
| 686 | if(readonly) { |
| 687 | dev->mtd_info.type = MTD_ROM; |
| 688 | dev->mtd_info.flags = MTD_CAP_ROM; |
| 689 | } else { |
| 690 | dev->mtd_info.type = MTD_RAM; |
| 691 | dev->mtd_info.flags = MTD_CAP_RAM; |
| 692 | dev->mtd_info.erase = blkmtd_erase; |
| 693 | dev->mtd_info.write = blkmtd_write; |
| 694 | dev->mtd_info.writev = default_mtd_writev; |
| 695 | dev->mtd_info.sync = blkmtd_sync; |
| 696 | } |
| 697 | dev->mtd_info.read = blkmtd_read; |
| 698 | dev->mtd_info.readv = default_mtd_readv; |
| 699 | dev->mtd_info.priv = dev; |
| 700 | dev->mtd_info.owner = THIS_MODULE; |
| 701 | |
| 702 | list_add(&dev->list, &blkmtd_device_list); |
| 703 | if (add_mtd_device(&dev->mtd_info)) { |
| 704 | /* Device didnt get added, so free the entry */ |
| 705 | list_del(&dev->list); |
| 706 | goto devinit_err; |
| 707 | } else { |
| 708 | info("mtd%d: [%s] erase_size = %dKiB %s", |
| 709 | dev->mtd_info.index, dev->mtd_info.name + strlen("blkmtd: "), |
| 710 | dev->mtd_info.erasesize >> 10, |
| 711 | readonly ? "(read-only)" : ""); |
| 712 | } |
| 713 | |
| 714 | return dev; |
| 715 | |
| 716 | devinit_err: |
| 717 | free_device(dev); |
| 718 | return NULL; |
| 719 | } |
| 720 | |
| 721 | |
| 722 | /* Cleanup and exit - sync the device and kill of the kernel thread */ |
| 723 | static void __devexit cleanup_blkmtd(void) |
| 724 | { |
| 725 | struct list_head *temp1, *temp2; |
| 726 | |
| 727 | /* Remove the MTD devices */ |
| 728 | list_for_each_safe(temp1, temp2, &blkmtd_device_list) { |
| 729 | struct blkmtd_dev *dev = list_entry(temp1, struct blkmtd_dev, |
| 730 | list); |
| 731 | blkmtd_sync(&dev->mtd_info); |
| 732 | del_mtd_device(&dev->mtd_info); |
| 733 | info("mtd%d: [%s] removed", dev->mtd_info.index, |
| 734 | dev->mtd_info.name + strlen("blkmtd: ")); |
| 735 | list_del(&dev->list); |
| 736 | free_device(dev); |
| 737 | } |
| 738 | } |
| 739 | |
| 740 | #ifndef MODULE |
| 741 | |
| 742 | /* Handle kernel boot params */ |
| 743 | |
| 744 | |
| 745 | static int __init param_blkmtd_device(char *str) |
| 746 | { |
| 747 | int i; |
| 748 | |
| 749 | for(i = 0; i < MAX_DEVICES; i++) { |
| 750 | device[i] = str; |
| 751 | DEBUG(2, "blkmtd: device setup: %d = %s\n", i, device[i]); |
| 752 | strsep(&str, ","); |
| 753 | } |
| 754 | return 1; |
| 755 | } |
| 756 | |
| 757 | |
| 758 | static int __init param_blkmtd_erasesz(char *str) |
| 759 | { |
| 760 | int i; |
| 761 | for(i = 0; i < MAX_DEVICES; i++) { |
| 762 | char *val = strsep(&str, ","); |
| 763 | if(val) |
| 764 | erasesz[i] = simple_strtoul(val, NULL, 0); |
| 765 | DEBUG(2, "blkmtd: erasesz setup: %d = %d\n", i, erasesz[i]); |
| 766 | } |
| 767 | |
| 768 | return 1; |
| 769 | } |
| 770 | |
| 771 | |
| 772 | static int __init param_blkmtd_ro(char *str) |
| 773 | { |
| 774 | int i; |
| 775 | for(i = 0; i < MAX_DEVICES; i++) { |
| 776 | char *val = strsep(&str, ","); |
| 777 | if(val) |
| 778 | ro[i] = simple_strtoul(val, NULL, 0); |
| 779 | DEBUG(2, "blkmtd: ro setup: %d = %d\n", i, ro[i]); |
| 780 | } |
| 781 | |
| 782 | return 1; |
| 783 | } |
| 784 | |
| 785 | |
| 786 | static int __init param_blkmtd_sync(char *str) |
| 787 | { |
| 788 | if(str[0] == '1') |
| 789 | sync = 1; |
| 790 | return 1; |
| 791 | } |
| 792 | |
| 793 | __setup("blkmtd_device=", param_blkmtd_device); |
| 794 | __setup("blkmtd_erasesz=", param_blkmtd_erasesz); |
| 795 | __setup("blkmtd_ro=", param_blkmtd_ro); |
| 796 | __setup("blkmtd_sync=", param_blkmtd_sync); |
| 797 | |
| 798 | #endif |
| 799 | |
| 800 | |
| 801 | /* Startup */ |
| 802 | static int __init init_blkmtd(void) |
| 803 | { |
| 804 | int i; |
| 805 | |
| 806 | info("version " VERSION); |
| 807 | /* Check args - device[0] is the bare minimum*/ |
| 808 | if(!device[0]) { |
| 809 | err("error: missing `device' name\n"); |
| 810 | return -EINVAL; |
| 811 | } |
| 812 | |
| 813 | for(i = 0; i < MAX_DEVICES; i++) |
| 814 | add_device(device[i], ro[i], erasesz[i] << 10); |
| 815 | |
| 816 | if(list_empty(&blkmtd_device_list)) |
| 817 | return -EINVAL; |
| 818 | |
| 819 | return 0; |
| 820 | } |
| 821 | |
| 822 | module_init(init_blkmtd); |
| 823 | module_exit(cleanup_blkmtd); |