target/linux/generic-2.6/patches-2.6.31/065-rootfs_split.patch

   1 --- a/drivers/mtd/Kconfig
   2 +++ b/drivers/mtd/Kconfig
   3 @@ -53,6 +53,16 @@ config MTD_TESTS
   4           should normally be compiled as kernel modules. The modules perform
   5           various checks and verifications when loaded.
   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/root_dev.h>
  27 +#include <linux/magic.h>
  28
  29  /* Our partition linked list */
  30  static LIST_HEAD(mtd_partitions);
  31 @@ -35,7 +37,7 @@ 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 @@ -502,6 +504,150 @@ 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 +
  48 +struct squashfs_super_block {
  49 +       __le32 s_magic;
  50 +       __le32 pad0[9];
  51 +       __le64 bytes_used;
  52 +};
  53 +
  54 +
  55 +static int split_squashfs(struct mtd_info *master, int offset, int *split_offset)
  56 +{
  57 +       struct squashfs_super_block sb;
  58 +       int len, ret;
  59 +
  60 +       ret = master->read(master, offset, sizeof(sb), &len, (void *) &sb);
  61 +       if (ret || (len != sizeof(sb))) {
  62 +               printk(KERN_ALERT "split_squashfs: error occured while reading "
  63 +                       "from \"%s\"\n", master->name);
  64 +               return -EINVAL;
  65 +       }
  66 +
  67 +       if (SQUASHFS_MAGIC != le32_to_cpu(sb.s_magic) ) {
  68 +               printk(KERN_ALERT "split_squashfs: no squashfs found in \"%s\"\n",
  69 +                       master->name);
  70 +               *split_offset = 0;
  71 +               return 0;
  72 +       }
  73 +
  74 +       if (le64_to_cpu((sb.bytes_used)) <= 0) {
  75 +               printk(KERN_ALERT "split_squashfs: squashfs is empty in \"%s\"\n",
  76 +                       master->name);
  77 +               *split_offset = 0;
  78 +               return 0;
  79 +       }
  80 +
  81 +       len = (u32) le64_to_cpu(sb.bytes_used);
  82 +       len += (offset & 0x000fffff);
  83 +       len +=  (master->erasesize - 1);
  84 +       len &= ~(master->erasesize - 1);
  85 +       len -= (offset & 0x000fffff);
  86 +       *split_offset = offset + len;
  87 +
  88 +       return 0;
  89 +}
  90 +
  91 +static int split_rootfs_data(struct mtd_info *master, struct mtd_info *rpart, const struct mtd_partition *part)
  92 +{
  93 +       struct mtd_partition *dpart;
  94 +       struct mtd_part *slave = NULL;
  95 +       int split_offset = 0;
  96 +       int ret;
  97 +
  98 +       ret = split_squashfs(master, part->offset, &split_offset);
  99 +       if (ret)
 100 +               return ret;
 101 +
 102 +       if (split_offset <= 0)
 103 +               return 0;
 104 +
 105 +       dpart = kmalloc(sizeof(*part)+sizeof(ROOTFS_SPLIT_NAME)+1, GFP_KERNEL);
 106 +       if (dpart == NULL) {
 107 +               printk(KERN_INFO "split_squashfs: no memory for partition \"%s\"\n",
 108 +                       ROOTFS_SPLIT_NAME);
 109 +               return -ENOMEM;
 110 +       }
 111 +
 112 +       memcpy(dpart, part, sizeof(*part));
 113 +       dpart->name = (unsigned char *)&dpart[1];
 114 +       strcpy(dpart->name, ROOTFS_SPLIT_NAME);
 115 +
 116 +       dpart->size -= split_offset - dpart->offset;
 117 +       dpart->offset = split_offset;
 118 +
 119 +       if (dpart == NULL)
 120 +               return 1;
 121 +
 122 +       printk(KERN_INFO "mtd: partition \"%s\" created automatically, ofs=%llX, len=%llX \n",
 123 +               ROOTFS_SPLIT_NAME, dpart->offset, dpart->size);
 124 +
 125 +       slave = add_one_partition(master, dpart, 0, split_offset);
 126 +       if (!slave) {
 127 +               kfree(dpart);
 128 +               return -ENOMEM;
 129 +       }
 130 +       rpart->split = &slave->mtd;
 131 +
 132 +       return 0;
 133 +}
 134 +
 135 +static int refresh_rootfs_split(struct mtd_info *mtd)
 136 +{
 137 +       struct mtd_partition tpart;
 138 +       struct mtd_part *part;
 139 +       char *name;
 140 +       //int index = 0;
 141 +       int offset, size;
 142 +       int ret;
 143 +
 144 +       part = PART(mtd);
 145 +
 146 +       /* check for the new squashfs offset first */
 147 +       ret = split_squashfs(part->master, part->offset, &offset);
 148 +       if (ret)
 149 +               return ret;
 150 +
 151 +       if ((offset > 0) && !mtd->split) {
 152 +               printk(KERN_INFO "%s: creating new split partition for \"%s\"\n", __func__, mtd->name);
 153 +               /* if we don't have a rootfs split partition, create a new one */
 154 +               tpart.name = (char *) mtd->name;
 155 +               tpart.size = mtd->size;
 156 +               tpart.offset = part->offset;
 157 +
 158 +               return split_rootfs_data(part->master, &part->mtd, &tpart);
 159 +       } else if ((offset > 0) && mtd->split) {
 160 +               /* update the offsets of the existing partition */
 161 +               size = mtd->size + part->offset - offset;
 162 +
 163 +               part = PART(mtd->split);
 164 +               part->offset = offset;
 165 +               part->mtd.size = size;
 166 +               printk(KERN_INFO "%s: %s partition \"" ROOTFS_SPLIT_NAME "\", offset: 0x%06x (0x%06x)\n",
 167 +                       __func__, (!strcmp(part->mtd.name, ROOTFS_SPLIT_NAME) ? "updating" : "creating"),
 168 +                       (u32) part->offset, (u32) part->mtd.size);
 169 +               name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
 170 +               strcpy(name, ROOTFS_SPLIT_NAME);
 171 +               part->mtd.name = name;
 172 +       } else if ((offset <= 0) && mtd->split) {
 173 +               printk(KERN_INFO "%s: removing partition \"%s\"\n", __func__, mtd->split->name);
 174 +
 175 +               /* mark existing partition as removed */
 176 +               part = PART(mtd->split);
 177 +               name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
 178 +               strcpy(name, ROOTFS_REMOVED_NAME);
 179 +               part->mtd.name = name;
 180 +               part->offset = 0;
 181 +               part->mtd.size = 0;
 182 +       }
 183 +
 184 +       return 0;
 185 +}
 186 +#endif /* CONFIG_MTD_ROOTFS_SPLIT */
 187 +
 188  /*
 189   * This function, given a master MTD object and a partition table, creates
 190   * and registers slave MTD objects which are bound to the master according to
 191 @@ -517,7 +663,7 @@ int add_mtd_partitions(struct mtd_info *
 192  {
 193         struct mtd_part *slave;
 194         uint64_t cur_offset = 0;
 195 -       int i;
 196 +       int i, ret;
 197
 198         printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
 199
 200 @@ -525,6 +671,21 @@ int add_mtd_partitions(struct mtd_info *
 201                 slave = add_one_partition(master, parts + i, i, cur_offset);
 202                 if (!slave)
 203                         return -ENOMEM;
 204 +
 205 +               if (!strcmp(parts[i].name, "rootfs")) {
 206 +#ifdef CONFIG_MTD_ROOTFS_ROOT_DEV
 207 +                       if (ROOT_DEV == 0) {
 208 +                               printk(KERN_NOTICE "mtd: partition \"rootfs\" "
 209 +                                       "set to be root filesystem\n");
 210 +                               ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, i);
 211 +                       }
 212 +#endif
 213 +#ifdef CONFIG_MTD_ROOTFS_SPLIT
 214 +                       ret = split_rootfs_data(master, &slave->mtd, &parts[i]);
 215 +                       /* if (ret == 0)
 216 +                               j++; */
 217 +#endif
 218 +               }
 219                 cur_offset = slave->offset + slave->mtd.size;
 220         }
 221
 222 @@ -532,6 +693,32 @@ int add_mtd_partitions(struct mtd_info *
 223  }
 224  EXPORT_SYMBOL(add_mtd_partitions);
 225
 226 +int refresh_mtd_partitions(struct mtd_info *mtd)
 227 +{
 228 +       int ret = 0;
 229 +
 230 +       if (IS_PART(mtd)) {
 231 +               struct mtd_part *part;
 232 +               struct mtd_info *master;
 233 +
 234 +               part = PART(mtd);
 235 +               master = part->master;
 236 +               if (master->refresh_device)
 237 +                       ret = master->refresh_device(master);
 238 +       }
 239 +
 240 +       if (!ret && mtd->refresh_device)
 241 +               ret = mtd->refresh_device(mtd);
 242 +
 243 +#ifdef CONFIG_MTD_ROOTFS_SPLIT
 244 +       if (!ret && IS_PART(mtd) && !strcmp(mtd->name, "rootfs"))
 245 +               refresh_rootfs_split(mtd);
 246 +#endif
 247 +
 248 +       return 0;
 249 +}
 250 +EXPORT_SYMBOL_GPL(refresh_mtd_partitions);
 251 +
 252  static DEFINE_SPINLOCK(part_parser_lock);
 253  static LIST_HEAD(part_parsers);
 254
 255 --- a/drivers/mtd/devices/block2mtd.c
 256 +++ b/drivers/mtd/devices/block2mtd.c
 257 @@ -29,6 +29,8 @@ struct block2mtd_dev {
 258         struct block_device *blkdev;
 259         struct mtd_info mtd;
 260         struct mutex write_mutex;
 261 +       rwlock_t bdev_mutex;
 262 +       char devname[0];
 263  };
 264
 265
 266 @@ -81,6 +83,12 @@ static int block2mtd_erase(struct mtd_in
 267         size_t len = instr->len;
 268         int err;
 269
 270 +       read_lock(&dev->bdev_mutex);
 271 +       if (!dev->blkdev) {
 272 +               err = -EINVAL;
 273 +               goto done;
 274 +       }
 275 +
 276         instr->state = MTD_ERASING;
 277         mutex_lock(&dev->write_mutex);
 278         err = _block2mtd_erase(dev, from, len);
 279 @@ -93,6 +101,10 @@ static int block2mtd_erase(struct mtd_in
 280
 281         instr->state = MTD_ERASE_DONE;
 282         mtd_erase_callback(instr);
 283 +
 284 +done:
 285 +       read_unlock(&dev->bdev_mutex);
 286 +
 287         return err;
 288  }
 289
 290 @@ -104,10 +116,14 @@ static int block2mtd_read(struct mtd_inf
 291         struct page *page;
 292         int index = from >> PAGE_SHIFT;
 293         int offset = from & (PAGE_SIZE-1);
 294 -       int cpylen;
 295 +       int cpylen, err = 0;
 296 +
 297 +       read_lock(&dev->bdev_mutex);
 298 +       if (!dev->blkdev || (from > mtd->size)) {
 299 +               err = -EINVAL;
 300 +               goto done;
 301 +       }
 302
 303 -       if (from > mtd->size)
 304 -               return -EINVAL;
 305         if (from + len > mtd->size)
 306                 len = mtd->size - from;
 307
 308 @@ -122,10 +138,14 @@ static int block2mtd_read(struct mtd_inf
 309                 len = len - cpylen;
 310
 311                 page = page_read(dev->blkdev->bd_inode->i_mapping, index);
 312 -               if (!page)
 313 -                       return -ENOMEM;
 314 -               if (IS_ERR(page))
 315 -                       return PTR_ERR(page);
 316 +               if (!page) {
 317 +                       err = -ENOMEM;
 318 +                       goto done;
 319 +               }
 320 +               if (IS_ERR(page)) {
 321 +                       err = PTR_ERR(page);
 322 +                       goto done;
 323 +               }
 324
 325                 memcpy(buf, page_address(page) + offset, cpylen);
 326                 page_cache_release(page);
 327 @@ -136,7 +156,10 @@ static int block2mtd_read(struct mtd_inf
 328                 offset = 0;
 329                 index++;
 330         }
 331 -       return 0;
 332 +
 333 +done:
 334 +       read_unlock(&dev->bdev_mutex);
 335 +       return err;
 336  }
 337
 338
 339 @@ -188,12 +211,22 @@ static int block2mtd_write(struct mtd_in
 340                 size_t *retlen, const u_char *buf)
 341  {
 342         struct block2mtd_dev *dev = mtd->priv;
 343 -       int err;
 344 +       int err = 0;
 345 +
 346 +       read_lock(&dev->bdev_mutex);
 347 +       if (!dev->blkdev) {
 348 +               err = -EINVAL;
 349 +               goto done;
 350 +       }
 351
 352         if (!len)
 353 -               return 0;
 354 -       if (to >= mtd->size)
 355 -               return -ENOSPC;
 356 +               goto done;
 357 +
 358 +       if (to >= mtd->size) {
 359 +               err = -ENOSPC;
 360 +               goto done;
 361 +       }
 362 +
 363         if (to + len > mtd->size)
 364                 len = mtd->size - to;
 365
 366 @@ -202,6 +235,9 @@ static int block2mtd_write(struct mtd_in
 367         mutex_unlock(&dev->write_mutex);
 368         if (err > 0)
 369                 err = 0;
 370 +
 371 +done:
 372 +       read_unlock(&dev->bdev_mutex);
 373         return err;
 374  }
 375
 376 @@ -210,52 +246,29 @@ static int block2mtd_write(struct mtd_in
 377  static void block2mtd_sync(struct mtd_info *mtd)
 378  {
 379         struct block2mtd_dev *dev = mtd->priv;
 380 -       sync_blockdev(dev->blkdev);
 381 -       return;
 382 -}
 383 -
 384 -
 385 -static void block2mtd_free_device(struct block2mtd_dev *dev)
 386 -{
 387 -       if (!dev)
 388 -               return;
 389 -
 390 -       kfree(dev->mtd.name);
 391
 392 -       if (dev->blkdev) {
 393 -               invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
 394 -                                       0, -1);
 395 -               close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE);
 396 -       }
 397 +       read_lock(&dev->bdev_mutex);
 398 +       if (dev->blkdev)
 399 +               sync_blockdev(dev->blkdev);
 400 +       read_unlock(&dev->bdev_mutex);
 401
 402 -       kfree(dev);
 403 +       return;
 404  }
 405
 406
 407 -/* FIXME: ensure that mtd->size % erase_size == 0 */
 408 -static struct block2mtd_dev *add_device(char *devname, int erase_size, const char *mtdname)
 409 +static int _open_bdev(struct block2mtd_dev *dev)
 410  {
 411         struct block_device *bdev;
 412 -       struct block2mtd_dev *dev;
 413 -       struct mtd_partition *part;
 414 -       char *name;
 415 -
 416 -       if (!devname)
 417 -               return NULL;
 418 -
 419 -       dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
 420 -       if (!dev)
 421 -               return NULL;
 422
 423         /* Get a handle on the device */
 424 -       bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, NULL);
 425 +       bdev = open_bdev_exclusive(dev->devname, FMODE_READ|FMODE_WRITE, NULL);
 426  #ifndef MODULE
 427         if (IS_ERR(bdev)) {
 428
 429                 /* We might not have rootfs mounted at this point. Try
 430                    to resolve the device name by other means. */
 431
 432 -               dev_t devt = name_to_dev_t(devname);
 433 +               dev_t devt = name_to_dev_t(dev->devname);
 434                 if (devt) {
 435                         bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
 436                 }
 437 @@ -263,17 +276,97 @@ static struct block2mtd_dev *add_device(
 438  #endif
 439
 440         if (IS_ERR(bdev)) {
 441 -               ERROR("error: cannot open device %s", devname);
 442 -               goto devinit_err;
 443 +               ERROR("error: cannot open device %s", dev->devname);
 444 +               return 1;
 445         }
 446         dev->blkdev = bdev;
 447
 448         if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
 449                 ERROR("attempting to use an MTD device as a block device");
 450 -               goto devinit_err;
 451 +               return 1;
 452         }
 453
 454 +       return 0;
 455 +}
 456 +
 457 +static void _close_bdev(struct block2mtd_dev *dev)
 458 +{
 459 +       struct block_device *bdev;
 460 +
 461 +       if (!dev->blkdev)
 462 +               return;
 463 +
 464 +       bdev = dev->blkdev;
 465 +       invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, 0, -1);
 466 +       close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE);
 467 +       dev->blkdev = NULL;
 468 +}
 469 +
 470 +static void block2mtd_free_device(struct block2mtd_dev *dev)
 471 +{
 472 +       if (!dev)
 473 +               return;
 474 +
 475 +       kfree(dev->mtd.name);
 476 +       _close_bdev(dev);
 477 +       kfree(dev);
 478 +}
 479 +
 480 +
 481 +static int block2mtd_refresh(struct mtd_info *mtd)
 482 +{
 483 +       struct block2mtd_dev *dev = mtd->priv;
 484 +       struct block_device *bdev;
 485 +       dev_t devt;
 486 +       int err = 0;
 487 +
 488 +       /* no other mtd function can run at this point */
 489 +       write_lock(&dev->bdev_mutex);
 490 +
 491 +       /* get the device number for the whole disk */
 492 +       devt = MKDEV(MAJOR(dev->blkdev->bd_dev), 0);
 493 +
 494 +       /* close the old block device */
 495 +       _close_bdev(dev);
 496 +
 497 +       /* open the whole disk, issue a partition rescan, then */
 498 +       bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
 499 +       if (!bdev || !bdev->bd_disk)
 500 +               err = -EINVAL;
 501 +       else {
 502 +               err = rescan_partitions(bdev->bd_disk, bdev);
 503 +       }
 504 +       if (bdev)
 505 +               close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE);
 506 +
 507 +       /* try to open the partition block device again */
 508 +       _open_bdev(dev);
 509 +       write_unlock(&dev->bdev_mutex);
 510 +
 511 +       return err;
 512 +}
 513 +
 514 +/* FIXME: ensure that mtd->size % erase_size == 0 */
 515 +static struct block2mtd_dev *add_device(char *devname, int erase_size, char *mtdname)
 516 +{
 517 +       struct block2mtd_dev *dev;
 518 +       struct mtd_partition *part;
 519 +       char *name;
 520 +
 521 +       if (!devname)
 522 +               return NULL;
 523 +
 524 +       dev = kzalloc(sizeof(struct block2mtd_dev) + strlen(devname) + 1, GFP_KERNEL);
 525 +       if (!dev)
 526 +               return NULL;
 527 +
 528 +       strcpy(dev->devname, devname);
 529 +
 530 +       if (_open_bdev(dev))
 531 +               goto devinit_err;
 532 +
 533         mutex_init(&dev->write_mutex);
 534 +       rwlock_init(&dev->bdev_mutex);
 535
 536         if (!mtdname)
 537                 mtdname = devname;
 538 @@ -297,6 +390,7 @@ static struct block2mtd_dev *add_device(
 539         dev->mtd.read = block2mtd_read;
 540         dev->mtd.priv = dev;
 541         dev->mtd.owner = THIS_MODULE;
 542 +       dev->mtd.refresh_device = block2mtd_refresh;
 543
 544         part = kzalloc(sizeof(struct mtd_partition), GFP_KERNEL);
 545         part->name = dev->mtd.name;
 546 --- a/drivers/mtd/mtdchar.c
 547 +++ b/drivers/mtd/mtdchar.c
 548 @@ -18,6 +18,7 @@
 549
 550  #include <linux/mtd/mtd.h>
 551  #include <linux/mtd/compatmac.h>
 552 +#include <linux/mtd/partitions.h>
 553
 554  #include <asm/uaccess.h>
 555
 556 @@ -814,6 +815,13 @@ static int mtd_ioctl(struct inode *inode
 557                 file->f_pos = 0;
 558                 break;
 559         }
 560 +#ifdef CONFIG_MTD_PARTITIONS
 561 +       case MTDREFRESH:
 562 +       {
 563 +               ret = refresh_mtd_partitions(mtd);
 564 +               break;
 565 +       }
 566 +#endif
 567
 568         default:
 569                 ret = -ENOTTY;
 570 --- a/include/linux/mtd/mtd.h
 571 +++ b/include/linux/mtd/mtd.h
 572 @@ -101,6 +101,7 @@ struct mtd_oob_ops {
 573         uint8_t         *oobbuf;
 574  };
 575
 576 +struct mtd_info;
 577  struct mtd_info {
 578         u_char type;
 579         uint32_t flags;
 580 @@ -241,6 +242,9 @@ struct mtd_info {
 581         struct device dev;
 582         int usecount;
 583
 584 +       int (*refresh_device)(struct mtd_info *mtd);
 585 +       struct mtd_info *split;
 586 +
 587         /* If the driver is something smart, like UBI, it may need to maintain
 588          * its own reference counting. The below functions are only for driver.
 589          * The driver may register its callbacks. These callbacks are not
 590 --- a/include/linux/mtd/partitions.h
 591 +++ b/include/linux/mtd/partitions.h
 592 @@ -34,12 +34,14 @@
 593   * erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
 594   */
 595
 596 +struct mtd_partition;
 597  struct mtd_partition {
 598         char *name;                     /* identifier string */
 599         uint64_t size;                  /* partition size */
 600         uint64_t offset;                /* offset within the master MTD space */
 601         uint32_t mask_flags;            /* master MTD flags to mask out for this partition */
 602         struct nand_ecclayout *ecclayout;       /* out of band layout for this partition (NAND only)*/
 603 +       int (*refresh_partition)(struct mtd_info *);
 604  };
 605
 606  #define MTDPART_OFS_NXTBLK     (-2)
 607 @@ -51,6 +53,7 @@ struct mtd_info;
 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 @@ -110,6 +110,7 @@ struct otp_info {
 618  #define MEMERASE64             _IOW('M', 20, struct erase_info_user64)
 619  #define MEMWRITEOOB64          _IOWR('M', 21, struct mtd_oob_buf64)
 620  #define MEMREADOOB64           _IOWR('M', 22, struct mtd_oob_buf64)
 621 +#define MTDREFRESH             _IO('M', 23)
 622
 623  /*
 624   * Obsolete legacy interface. Keep it in order not to break userspace