+int cfi_varsize_frob(struct mtd_info *mtd, varsize_frob_t frob,
+ loff_t ofs, size_t len, void *thunk)
+{
+ struct map_info *map = mtd->priv;
+ struct cfi_private *cfi = map->fldrv_priv;
+ unsigned long adr;
+ int chipnum, ret = 0;
+ int i, first;
+ struct mtd_erase_region_info *regions = mtd->eraseregions;
+
+ if (ofs > mtd->size)
+ return -EINVAL;
+
+ if ((len + ofs) > mtd->size)
+ return -EINVAL;
+
+ /* Check that both start and end of the requested erase are
+ * aligned with the erasesize at the appropriate addresses.
+ */
+
+ i = 0;
+
+ /* Skip all erase regions which are ended before the start of
+ the requested erase. Actually, to save on the calculations,
+ we skip to the first erase region which starts after the
+ start of the requested erase, and then go back one.
+ */
+
+ while (i < mtd->numeraseregions && ofs >= regions[i].offset)
+ i++;
+ i--;
+
+ /* OK, now i is pointing at the erase region in which this
+ erase request starts. Check the start of the requested
+ erase range is aligned with the erase size which is in
+ effect here.
+ */
+
+ if (ofs & (regions[i].erasesize-1))
+ return -EINVAL;
+
+ /* Remember the erase region we start on */
+ first = i;
+
+ /* Next, check that the end of the requested erase is aligned
+ * with the erase region at that address.
+ */
+
+ while (i<mtd->numeraseregions && (ofs + len) >= regions[i].offset)
+ i++;
+
+ /* As before, drop back one to point at the region in which
+ the address actually falls
+ */
+ i--;
+
+ if ((ofs + len) & (regions[i].erasesize-1))
+ return -EINVAL;
+
+ chipnum = ofs >> cfi->chipshift;
+ adr = ofs - (chipnum << cfi->chipshift);
+
+ i=first;
+
+ while(len) {
+ int size = regions[i].erasesize;
+
+ ret = (*frob)(map, &cfi->chips[chipnum], adr, size, thunk);
+
+ if (ret)
+ return ret;
+
+ adr += size;
+ ofs += size;
+ len -= size;
+
+ if (ofs == regions[i].offset + size * regions[i].numblocks)
+ i++;
+
+ if (adr >> cfi->chipshift) {
+ adr = 0;
+ chipnum++;
+
+ if (chipnum >= cfi->numchips)
+ break;
+ }
+ }
+
+ return 0;
+}
+
+EXPORT_SYMBOL(cfi_varsize_frob);
+