mtd: nand: erase block before marking bad

Many NAND flash systems (especially those with MLC NAND) cannot be
reliably written twice in a row. For instance, when marking a bad block,
the block may already have data written to it, and so we should attempt
to erase the block before writing a bad block marker to its OOB region.

We can ignore erase failures, since the block may be bad such that it
cannot be erased properly; we still attempt to write zeros to its spare
area.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 8a393f9e6027d1be3dcf3d149dfc277e8941fca2..cd827d5a825516947598c0c1ffb802288366588b 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -394,6 +394,17 @@ static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
        uint8_t buf[2] = { 0, 0 };
        int block, ret, i = 0;
 
+       if (!(chip->bbt_options & NAND_BBT_USE_FLASH)) {
+               struct erase_info einfo;
+
+               /* Attempt erase before marking OOB */
+               memset(&einfo, 0, sizeof(einfo));
+               einfo.mtd = mtd;
+               einfo.addr = ofs;
+               einfo.len = 1 << chip->phys_erase_shift;
+               nand_erase_nand(mtd, &einfo, 0);
+       }
+
        if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
                ofs += mtd->erasesize - mtd->writesize;