target/linux/generic-2.6/patches-2.6.27/065-rootfs_split.patch

   1 --- a/drivers/mtd/Kconfig
   2 +++ b/drivers/mtd/Kconfig
   3 @@ -45,6 +45,16 @@ config MTD_PARTITIONS
   4           devices. Partitioning on NFTL 'devices' is a different - that's the
   5           'normal' form of partitioning used on a block device.
   6
   7 +config MTD_ROOTFS_ROOT_DEV
   8 +       bool "Automatically set 'rootfs' partition to be root filesystem"
   9 +       depends on MTD_PARTITIONS
  10 +       default y
  11 +
  12 +config MTD_ROOTFS_SPLIT
  13 +       bool "Automatically split 'rootfs' partition for squashfs"
  14 +       depends on MTD_PARTITIONS
  15 +       default y
  16 +
  17  config MTD_REDBOOT_PARTS
  18         tristate "RedBoot partition table parsing"
  19         depends on MTD_PARTITIONS
  20 --- a/drivers/mtd/mtdpart.c
  21 +++ b/drivers/mtd/mtdpart.c
  22 @@ -18,6 +18,8 @@
  23  #include <linux/mtd/mtd.h>
  24  #include <linux/mtd/partitions.h>
  25  #include <linux/mtd/compatmac.h>
  26 +#include <linux/squashfs_fs.h>
  27 +#include <linux/root_dev.h>
  28
  29  /* Our partition linked list */
  30  static LIST_HEAD(mtd_partitions);
  31 @@ -37,7 +39,7 @@ struct mtd_part {
  32   * the pointer to that structure with this macro.
  33   */
  34  #define PART(x)  ((struct mtd_part *)(x))
  35 -
  36 +#define IS_PART(mtd) (mtd->read == part_read)
  37
  38  /*
  39   * MTD methods which simply translate the effective address and pass through
  40 @@ -489,6 +491,147 @@ out_register:
  41         return slave;
  42  }
  43
  44 +#ifdef CONFIG_MTD_ROOTFS_SPLIT
  45 +#define ROOTFS_SPLIT_NAME "rootfs_data"
  46 +#define ROOTFS_REMOVED_NAME "<removed>"
  47 +static int split_squashfs(struct mtd_info *master, int offset, int *split_offset)
  48 +{
  49 +       struct squashfs_super_block sb;
  50 +       int len, ret;
  51 +
  52 +       ret = master->read(master, offset, sizeof(sb), &len, (void *) &sb);
  53 +       if (ret || (len != sizeof(sb))) {
  54 +               printk(KERN_ALERT "split_squashfs: error occured while reading "
  55 +                       "from \"%s\"\n", master->name);
  56 +               return -EINVAL;
  57 +       }
  58 +
  59 +       if (sb.s_magic != SQUASHFS_MAGIC) {
  60 +               printk(KERN_ALERT "split_squashfs: no squashfs found in \"%s\"\n",
  61 +                       master->name);
  62 +               *split_offset = 0;
  63 +               return 0;
  64 +       }
  65 +
  66 +       if (sb.bytes_used <= 0) {
  67 +               printk(KERN_ALERT "split_squashfs: squashfs is empty in \"%s\"\n",
  68 +                       master->name);
  69 +               *split_offset = 0;
  70 +               return 0;
  71 +       }
  72 +
  73 +       len = (u32) sb.bytes_used;
  74 +       len += (offset & 0x000fffff);
  75 +       len +=  (master->erasesize - 1);
  76 +       len &= ~(master->erasesize - 1);
  77 +       len -= (offset & 0x000fffff);
  78 +       *split_offset = offset + len;
  79 +
  80 +       return 0;
  81 +}
  82 +
  83 +static int split_rootfs_data(struct mtd_info *master, struct mtd_info *rpart, const struct mtd_partition *part,
  84 +               int index)
  85 +{
  86 +       struct mtd_partition *dpart;
  87 +       struct mtd_part *slave = NULL;
  88 +       int split_offset = 0;
  89 +       int ret;
  90 +
  91 +       ret = split_squashfs(master, part->offset, &split_offset);
  92 +       if (ret)
  93 +               return ret;
  94 +
  95 +       if (split_offset <= 0)
  96 +               return 0;
  97 +
  98 +       dpart = kmalloc(sizeof(*part)+sizeof(ROOTFS_SPLIT_NAME)+1, GFP_KERNEL);
  99 +       if (dpart == NULL) {
 100 +               printk(KERN_INFO "split_squashfs: no memory for partition \"%s\"\n",
 101 +                       ROOTFS_SPLIT_NAME);
 102 +               return -ENOMEM;
 103 +       }
 104 +
 105 +       memcpy(dpart, part, sizeof(*part));
 106 +       dpart->name = (unsigned char *)&dpart[1];
 107 +       strcpy(dpart->name, ROOTFS_SPLIT_NAME);
 108 +
 109 +       dpart->size -= split_offset - dpart->offset;
 110 +       dpart->offset = split_offset;
 111 +
 112 +       if (dpart == NULL)
 113 +               return 1;
 114 +
 115 +       printk(KERN_INFO "mtd: partition \"%s\" created automatically, ofs=%X, len=%X \n",
 116 +               ROOTFS_SPLIT_NAME, dpart->offset, dpart->size);
 117 +
 118 +       slave = add_one_partition(master, dpart, index, split_offset);
 119 +       if (!slave) {
 120 +               kfree(dpart);
 121 +               return -ENOMEM;
 122 +       }
 123 +       rpart->split = &slave->mtd;
 124 +
 125 +       return 0;
 126 +}
 127 +
 128 +static int refresh_rootfs_split(struct mtd_info *mtd)
 129 +{
 130 +       struct mtd_partition tpart;
 131 +       struct mtd_part *part;
 132 +       char *name;
 133 +       int index = 0;
 134 +       int offset, size;
 135 +       int ret;
 136 +
 137 +       part = PART(mtd);
 138 +
 139 +       /* check for the new squashfs offset first */
 140 +       ret = split_squashfs(part->master, part->offset, &offset);
 141 +       if (ret)
 142 +               return ret;
 143 +
 144 +       if ((offset > 0) && !mtd->split) {
 145 +               printk(KERN_INFO "%s: creating new split partition for \"%s\"\n", __func__, mtd->name);
 146 +               /* if we don't have a rootfs split partition, create a new one */
 147 +               tpart.name = (char *) mtd->name;
 148 +               tpart.size = mtd->size;
 149 +               tpart.offset = part->offset;
 150 +
 151 +               /* find the index of the last partition */
 152 +               if (!list_empty(&mtd_partitions))
 153 +                       index = list_first_entry(&mtd_partitions, struct mtd_part, list)->index + 1;
 154 +
 155 +               return split_rootfs_data(part->master, &part->mtd, &tpart, index);
 156 +       } else if ((offset > 0) && mtd->split) {
 157 +               /* update the offsets of the existing partition */
 158 +               size = mtd->size + part->offset - offset;
 159 +
 160 +               part = PART(mtd->split);
 161 +               part->offset = offset;
 162 +               part->mtd.size = size;
 163 +               printk(KERN_INFO "%s: %s partition \"" ROOTFS_SPLIT_NAME "\", offset: 0x%06x (0x%06x)\n",
 164 +                       __func__, (!strcmp(part->mtd.name, ROOTFS_SPLIT_NAME) ? "updating" : "creating"),
 165 +                       part->offset, part->mtd.size);
 166 +               name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
 167 +               strcpy(name, ROOTFS_SPLIT_NAME);
 168 +               part->mtd.name = name;
 169 +       } else if ((offset <= 0) && mtd->split) {
 170 +               printk(KERN_INFO "%s: removing partition \"%s\"\n", __func__, mtd->split->name);
 171 +
 172 +               /* mark existing partition as removed */
 173 +               part = PART(mtd->split);
 174 +               name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
 175 +               strcpy(name, ROOTFS_REMOVED_NAME);
 176 +               part->mtd.name = name;
 177 +               part->offset = 0;
 178 +               part->mtd.size = 0;
 179 +       }
 180 +
 181 +       return 0;
 182 +}
 183 +#endif /* CONFIG_MTD_ROOTFS_SPLIT */
 184 +
 185  /*
 186   * This function, given a master MTD object and a partition table, creates
 187   * and registers slave MTD objects which are bound to the master according to
 188 @@ -502,14 +645,29 @@ int add_mtd_partitions(struct mtd_info *
 189  {
 190         struct mtd_part *slave;
 191         u_int32_t cur_offset = 0;
 192 -       int i;
 193 +       int i, j, ret;
 194
 195         printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
 196
 197 -       for (i = 0; i < nbparts; i++) {
 198 -               slave = add_one_partition(master, parts + i, i, cur_offset);
 199 +       for (i = 0, j = 0; i < nbparts; i++) {
 200 +               slave = add_one_partition(master, parts + i, j++, cur_offset);
 201                 if (!slave)
 202                         return -ENOMEM;
 203 +
 204 +               if (!strcmp(parts[i].name, "rootfs") && slave->registered) {
 205 +#ifdef CONFIG_MTD_ROOTFS_ROOT_DEV
 206 +                       if (ROOT_DEV == 0) {
 207 +                               printk(KERN_NOTICE "mtd: partition \"rootfs\" "
 208 +                                       "set to be root filesystem\n");
 209 +                               ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, slave->mtd.index);
 210 +                       }
 211 +#endif
 212 +#ifdef CONFIG_MTD_ROOTFS_SPLIT
 213 +                       ret = split_rootfs_data(master, &slave->mtd, &parts[i], j);
 214 +                       if (ret == 0)
 215 +                               j++;
 216 +#endif
 217 +               }
 218                 cur_offset = slave->offset + slave->mtd.size;
 219         }
 220
 221 @@ -517,6 +675,32 @@ int add_mtd_partitions(struct mtd_info *
 222  }
 223  EXPORT_SYMBOL(add_mtd_partitions);
 224
 225 +int refresh_mtd_partitions(struct mtd_info *mtd)
 226 +{
 227 +       int ret = 0;
 228 +
 229 +       if (IS_PART(mtd)) {
 230 +               struct mtd_part *part;
 231 +               struct mtd_info *master;
 232 +
 233 +               part = PART(mtd);
 234 +               master = part->master;
 235 +               if (master->refresh_device)
 236 +                       ret = master->refresh_device(master);
 237 +       }
 238 +
 239 +       if (!ret && mtd->refresh_device)
 240 +               ret = mtd->refresh_device(mtd);
 241 +
 242 +#ifdef CONFIG_MTD_ROOTFS_SPLIT
 243 +       if (!ret && IS_PART(mtd) && !strcmp(mtd->name, "rootfs"))
 244 +               refresh_rootfs_split(mtd);
 245 +#endif
 246 +
 247 +       return 0;
 248 +}
 249 +EXPORT_SYMBOL_GPL(refresh_mtd_partitions);
 250 +
 251  static DEFINE_SPINLOCK(part_parser_lock);
 252  static LIST_HEAD(part_parsers);
 253
 254 --- a/drivers/mtd/devices/block2mtd.c
 255 +++ b/drivers/mtd/devices/block2mtd.c
 256 @@ -29,6 +29,8 @@ struct block2mtd_dev {
 257         struct block_device *blkdev;
 258         struct mtd_info mtd;
 259         struct mutex write_mutex;
 260 +       rwlock_t bdev_mutex;
 261 +       char devname[0];
 262  };
 263
 264
 265 @@ -81,6 +83,12 @@ static int block2mtd_erase(struct mtd_in
 266         size_t len = instr->len;
 267         int err;
 268
 269 +       read_lock(&dev->bdev_mutex);
 270 +       if (!dev->blkdev) {
 271 +               err = -EINVAL;
 272 +               goto done;
 273 +       }
 274 +
 275         instr->state = MTD_ERASING;
 276         mutex_lock(&dev->write_mutex);
 277         err = _block2mtd_erase(dev, from, len);
 278 @@ -93,6 +101,10 @@ static int block2mtd_erase(struct mtd_in
 279
 280         instr->state = MTD_ERASE_DONE;
 281         mtd_erase_callback(instr);
 282 +
 283 +done:
 284 +       read_unlock(&dev->bdev_mutex);
 285 +
 286         return err;
 287  }
 288
 289 @@ -104,10 +116,14 @@ static int block2mtd_read(struct mtd_inf
 290         struct page *page;
 291         int index = from >> PAGE_SHIFT;
 292         int offset = from & (PAGE_SIZE-1);
 293 -       int cpylen;
 294 +       int cpylen, err = 0;
 295 +
 296 +       read_lock(&dev->bdev_mutex);
 297 +       if (!dev->blkdev || (from > mtd->size)) {
 298 +               err = -EINVAL;
 299 +               goto done;
 300 +       }
 301
 302 -       if (from > mtd->size)
 303 -               return -EINVAL;
 304         if (from + len > mtd->size)
 305                 len = mtd->size - from;
 306
 307 @@ -122,10 +138,14 @@ static int block2mtd_read(struct mtd_inf
 308                 len = len - cpylen;
 309
 310                 page = page_read(dev->blkdev->bd_inode->i_mapping, index);
 311 -               if (!page)
 312 -                       return -ENOMEM;
 313 -               if (IS_ERR(page))
 314 -                       return PTR_ERR(page);
 315 +               if (!page) {
 316 +                       err = -ENOMEM;
 317 +                       goto done;
 318 +               }
 319 +               if (IS_ERR(page)) {
 320 +                       err = PTR_ERR(page);
 321 +                       goto done;
 322 +               }
 323
 324                 memcpy(buf, page_address(page) + offset, cpylen);
 325                 page_cache_release(page);
 326 @@ -136,7 +156,10 @@ static int block2mtd_read(struct mtd_inf
 327                 offset = 0;
 328                 index++;
 329         }
 330 -       return 0;
 331 +
 332 +done:
 333 +       read_unlock(&dev->bdev_mutex);
 334 +       return err;
 335  }
 336
 337
 338 @@ -188,12 +211,22 @@ static int block2mtd_write(struct mtd_in
 339                 size_t *retlen, const u_char *buf)
 340  {
 341         struct block2mtd_dev *dev = mtd->priv;
 342 -       int err;
 343 +       int err = 0;
 344 +
 345 +       read_lock(&dev->bdev_mutex);
 346 +       if (!dev->blkdev) {
 347 +               err = -EINVAL;
 348 +               goto done;
 349 +       }
 350
 351         if (!len)
 352 -               return 0;
 353 -       if (to >= mtd->size)
 354 -               return -ENOSPC;
 355 +               goto done;
 356 +
 357 +       if (to >= mtd->size) {
 358 +               err = -ENOSPC;
 359 +               goto done;
 360 +       }
 361 +
 362         if (to + len > mtd->size)
 363                 len = mtd->size - to;
 364
 365 @@ -202,6 +235,9 @@ static int block2mtd_write(struct mtd_in
 366         mutex_unlock(&dev->write_mutex);
 367         if (err > 0)
 368                 err = 0;
 369 +
 370 +done:
 371 +       read_unlock(&dev->bdev_mutex);
 372         return err;
 373  }
 374
 375 @@ -210,52 +246,29 @@ static int block2mtd_write(struct mtd_in
 376  static void block2mtd_sync(struct mtd_info *mtd)
 377  {
 378         struct block2mtd_dev *dev = mtd->priv;
 379 -       sync_blockdev(dev->blkdev);
 380 -       return;
 381 -}
 382 -
 383 -
 384 -static void block2mtd_free_device(struct block2mtd_dev *dev)
 385 -{
 386 -       if (!dev)
 387 -               return;
 388 -
 389 -       kfree(dev->mtd.name);
 390
 391 -       if (dev->blkdev) {
 392 -               invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
 393 -                                       0, -1);
 394 -               close_bdev_excl(dev->blkdev);
 395 -       }
 396 +       read_lock(&dev->bdev_mutex);
 397 +       if (dev->blkdev)
 398 +               sync_blockdev(dev->blkdev);
 399 +       read_unlock(&dev->bdev_mutex);
 400
 401 -       kfree(dev);
 402 +       return;
 403  }
 404
 405
 406 -/* FIXME: ensure that mtd->size % erase_size == 0 */
 407 -static struct block2mtd_dev *add_device(char *devname, int erase_size, const char *mtdname)
 408 +static int _open_bdev(struct block2mtd_dev *dev)
 409  {
 410         struct block_device *bdev;
 411 -       struct block2mtd_dev *dev;
 412 -       struct mtd_partition *part;
 413 -       char *name;
 414 -
 415 -       if (!devname)
 416 -               return NULL;
 417 -
 418 -       dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
 419 -       if (!dev)
 420 -               return NULL;
 421
 422         /* Get a handle on the device */
 423 -       bdev = open_bdev_excl(devname, O_RDWR, NULL);
 424 +       bdev = open_bdev_excl(dev->devname, O_RDWR, NULL);
 425  #ifndef MODULE
 426         if (IS_ERR(bdev)) {
 427
 428                 /* We might not have rootfs mounted at this point. Try
 429                    to resolve the device name by other means. */
 430
 431 -               dev_t devt = name_to_dev_t(devname);
 432 +               dev_t devt = name_to_dev_t(dev->devname);
 433                 if (devt) {
 434                         bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
 435                 }
 436 @@ -263,17 +276,97 @@ static struct block2mtd_dev *add_device(
 437  #endif
 438
 439         if (IS_ERR(bdev)) {
 440 -               ERROR("error: cannot open device %s", devname);
 441 -               goto devinit_err;
 442 +               ERROR("error: cannot open device %s", dev->devname);
 443 +               return 1;
 444         }
 445         dev->blkdev = bdev;
 446
 447         if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
 448                 ERROR("attempting to use an MTD device as a block device");
 449 -               goto devinit_err;
 450 +               return 1;
 451         }
 452
 453 +       return 0;
 454 +}
 455 +
 456 +static void _close_bdev(struct block2mtd_dev *dev)
 457 +{
 458 +       struct block_device *bdev;
 459 +
 460 +       if (!dev->blkdev)
 461 +               return;
 462 +
 463 +       bdev = dev->blkdev;
 464 +       invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, 0, -1);
 465 +       close_bdev_excl(dev->blkdev);
 466 +       dev->blkdev = NULL;
 467 +}
 468 +
 469 +static void block2mtd_free_device(struct block2mtd_dev *dev)
 470 +{
 471 +       if (!dev)
 472 +               return;
 473 +
 474 +       kfree(dev->mtd.name);
 475 +       _close_bdev(dev);
 476 +       kfree(dev);
 477 +}
 478 +
 479 +
 480 +static int block2mtd_refresh(struct mtd_info *mtd)
 481 +{
 482 +       struct block2mtd_dev *dev = mtd->priv;
 483 +       struct block_device *bdev;
 484 +       dev_t devt;
 485 +       int err = 0;
 486 +
 487 +       /* no other mtd function can run at this point */
 488 +       write_lock(&dev->bdev_mutex);
 489 +
 490 +       /* get the device number for the whole disk */
 491 +       devt = MKDEV(MAJOR(dev->blkdev->bd_dev), 0);
 492 +
 493 +       /* close the old block device */
 494 +       _close_bdev(dev);
 495 +
 496 +       /* open the whole disk, issue a partition rescan, then */
 497 +       bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
 498 +       if (!bdev || !bdev->bd_disk)
 499 +               err = -EINVAL;
 500 +       else {
 501 +               err = rescan_partitions(bdev->bd_disk, bdev);
 502 +       }
 503 +       if (bdev)
 504 +               close_bdev_excl(bdev);
 505 +
 506 +       /* try to open the partition block device again */
 507 +       _open_bdev(dev);
 508 +       write_unlock(&dev->bdev_mutex);
 509 +
 510 +       return err;
 511 +}
 512 +
 513 +/* FIXME: ensure that mtd->size % erase_size == 0 */
 514 +static struct block2mtd_dev *add_device(char *devname, int erase_size, char *mtdname)
 515 +{
 516 +       struct block2mtd_dev *dev;
 517 +       struct mtd_partition *part;
 518 +       char *name;
 519 +
 520 +       if (!devname)
 521 +               return NULL;
 522 +
 523 +       dev = kzalloc(sizeof(struct block2mtd_dev) + strlen(devname) + 1, GFP_KERNEL);
 524 +       if (!dev)
 525 +               return NULL;
 526 +
 527 +       strcpy(dev->devname, devname);
 528 +
 529 +       if (_open_bdev(dev))
 530 +               goto devinit_err;
 531 +
 532         mutex_init(&dev->write_mutex);
 533 +       rwlock_init(&dev->bdev_mutex);
 534
 535         if (!mtdname)
 536                 mtdname = devname;
 537 @@ -297,6 +390,7 @@ static struct block2mtd_dev *add_device(
 538         dev->mtd.read = block2mtd_read;
 539         dev->mtd.priv = dev;
 540         dev->mtd.owner = THIS_MODULE;
 541 +       dev->mtd.refresh_device = block2mtd_refresh;
 542
 543         part = kzalloc(sizeof(struct mtd_partition), GFP_KERNEL);
 544         part->name = dev->mtd.name;
 545 --- a/drivers/mtd/mtdchar.c
 546 +++ b/drivers/mtd/mtdchar.c
 547 @@ -16,6 +16,7 @@
 548
 549  #include <linux/mtd/mtd.h>
 550  #include <linux/mtd/compatmac.h>
 551 +#include <linux/mtd/partitions.h>
 552
 553  #include <asm/uaccess.h>
 554
 555 @@ -771,6 +772,13 @@ static int mtd_ioctl(struct inode *inode
 556                 file->f_pos = 0;
 557                 break;
 558         }
 559 +#ifdef CONFIG_MTD_PARTITIONS
 560 +       case MTDREFRESH:
 561 +       {
 562 +               ret = refresh_mtd_partitions(mtd);
 563 +               break;
 564 +       }
 565 +#endif
 566
 567         default:
 568                 ret = -ENOTTY;
 569 --- a/include/linux/mtd/mtd.h
 570 +++ b/include/linux/mtd/mtd.h
 571 @@ -96,6 +96,7 @@ struct mtd_oob_ops {
 572         uint8_t         *oobbuf;
 573  };
 574
 575 +struct mtd_info;
 576  struct mtd_info {
 577         u_char type;
 578         u_int32_t flags;
 579 @@ -211,6 +212,9 @@ struct mtd_info {
 580         struct module *owner;
 581         int usecount;
 582
 583 +       int (*refresh_device)(struct mtd_info *mtd);
 584 +       struct mtd_info *split;
 585 +
 586         /* If the driver is something smart, like UBI, it may need to maintain
 587          * its own reference counting. The below functions are only for driver.
 588          * The driver may register its callbacks. These callbacks are not
 589 --- a/include/linux/mtd/partitions.h
 590 +++ b/include/linux/mtd/partitions.h
 591 @@ -34,6 +34,7 @@
 592   * erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
 593   */
 594
 595 +struct mtd_partition;
 596  struct mtd_partition {
 597         char *name;                     /* identifier string */
 598         u_int32_t size;                 /* partition size */
 599 @@ -41,6 +42,7 @@ struct mtd_partition {
 600         u_int32_t mask_flags;           /* master MTD flags to mask out for this partition */
 601         struct nand_ecclayout *ecclayout;       /* out of band layout for this partition (NAND only)*/
 602         struct mtd_info **mtdp;         /* pointer to store the MTD object */
 603 +       int (*refresh_partition)(struct mtd_info *);
 604  };
 605
 606  #define MTDPART_OFS_NXTBLK     (-2)
 607 @@ -50,6 +52,7 @@ struct mtd_partition {
 608
 609  int add_mtd_partitions(struct mtd_info *, const struct mtd_partition *, int);
 610  int del_mtd_partitions(struct mtd_info *);
 611 +int refresh_mtd_partitions(struct mtd_info *);
 612
 613  /*
 614   * Functions dealing with the various ways of partitioning the space
 615 --- a/include/mtd/mtd-abi.h
 616 +++ b/include/mtd/mtd-abi.h
 617 @@ -93,6 +93,7 @@ struct otp_info {
 618  #define ECCGETLAYOUT           _IOR('M', 17, struct nand_ecclayout)
 619  #define ECCGETSTATS            _IOR('M', 18, struct mtd_ecc_stats)
 620  #define MTDFILEMODE            _IO('M', 19)
 621 +#define MTDREFRESH             _IO('M', 23)
 622
 623  /*
 624   * Obsolete legacy interface. Keep it in order not to break userspace