+/**
+ * get_bbt_block - Get the first valid eraseblock suitable to store a BBT
+ * @this: the NAND device
+ * @td: the BBT description
+ * @md: the mirror BBT descriptor
+ * @chip: the CHIP selector
+ *
+ * This functions returns a positive block number pointing a valid eraseblock
+ * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if
+ * all blocks are already used of marked bad. If td->pages[chip] was already
+ * pointing to a valid block we re-use it, otherwise we search for the next
+ * valid one.
+ */
+static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td,
+ struct nand_bbt_descr *md, int chip)
+{
+ int startblock, dir, page, numblocks, i;
+
+ /*
+ * There was already a version of the table, reuse the page. This
+ * applies for absolute placement too, as we have the page number in
+ * td->pages.
+ */
+ if (td->pages[chip] != -1)
+ return td->pages[chip] >>
+ (this->bbt_erase_shift - this->page_shift);
+
+ numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
+ if (!(td->options & NAND_BBT_PERCHIP))
+ numblocks *= this->numchips;
+
+ /*
+ * Automatic placement of the bad block table. Search direction
+ * top -> down?
+ */
+ if (td->options & NAND_BBT_LASTBLOCK) {
+ startblock = numblocks * (chip + 1) - 1;
+ dir = -1;
+ } else {
+ startblock = chip * numblocks;
+ dir = 1;
+ }
+
+ for (i = 0; i < td->maxblocks; i++) {
+ int block = startblock + dir * i;
+
+ /* Check, if the block is bad */
+ switch (bbt_get_entry(this, block)) {
+ case BBT_BLOCK_WORN:
+ case BBT_BLOCK_FACTORY_BAD:
+ continue;
+ }
+
+ page = block << (this->bbt_erase_shift - this->page_shift);
+
+ /* Check, if the block is used by the mirror table */
+ if (!md || md->pages[chip] != page)
+ return block;
+ }
+
+ return -ENOSPC;
+}
+
+/**
+ * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
+ * @this: the NAND device
+ * @td: the BBT description
+ * @chip: the CHIP selector
+ * @block: the BBT block to mark
+ *
+ * Blocks reserved for BBT can become bad. This functions is an helper to mark
+ * such blocks as bad. It takes care of updating the in-memory BBT, marking the
+ * block as bad using a bad block marker and invalidating the associated
+ * td->pages[] entry.
+ */
+static void mark_bbt_block_bad(struct nand_chip *this,
+ struct nand_bbt_descr *td,
+ int chip, int block)
+{
+ struct mtd_info *mtd = nand_to_mtd(this);
+ loff_t to;
+ int res;
+
+ bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+ to = (loff_t)block << this->bbt_erase_shift;
+ res = this->block_markbad(mtd, to);
+ if (res)
+ pr_warn("nand_bbt: error %d while marking block %d bad\n",
+ res, block);
+
+ td->pages[chip] = -1;
+}
+