Search the specified (first and, second or last) page in a block for
the BBT. Support Hamming or Advanced Flex Mode (AFM) BBMs too.

Signed-off-by: Lee Jones <lee.jo...@linaro.org>
---
 drivers/mtd/nand/stm_nand_bch.c | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c
index 32d2211..7d242ad 100644
--- a/drivers/mtd/nand/stm_nand_bch.c
+++ b/drivers/mtd/nand/stm_nand_bch.c
@@ -818,6 +818,66 @@ static int bbt_is_block_bad(uint8_t *bbt, uint32_t block)
        return bbt_get_block_mark(bbt, block) == BBT_MARK_GOOD ? 0 : 1;
 }
 
+/* Scan page for BBM(s), according to specified BBT options */
+static int nandi_scan_bad_block_markers_page(struct nandi_controller *nandi,
+                                            uint32_t page)
+{
+       struct mtd_info *mtd = &nandi->info.mtd;
+       struct nand_chip *chip = mtd->priv;
+       uint8_t *oob_buf = nandi->oob_buf;
+       int i, e;
+
+       /* Read the OOB area */
+       flex_read_raw(nandi, page, mtd->writesize, oob_buf, mtd->oobsize);
+
+       if (oob_buf[chip->badblockpos] == 0xff)
+               return 0;
+
+       /* Tolerate 'alien' Hamming Boot Mode ECC */
+       e = 0;
+       for (i = 0; i < mtd->oobsize; i += 16)
+               e += hweight8(oob_buf[i + 3] ^ 'B');
+       if (e <= 1)
+               return 0;
+
+       /* Tolerate 'alien' Hamming AFM ECC */
+       e = 0;
+       for (i = 0; i < mtd->oobsize; i += 16) {
+               e += hweight8(oob_buf[i + 3] ^ 'A');
+               e += hweight8(oob_buf[i + 4] ^ 'F');
+               e += hweight8(oob_buf[i + 5] ^ 'M');
+               if (e <= 1)
+                       return 0;
+       }
+
+       return 1;
+}
+
+/* Scan block for BBM(s), according to specified BBT options */
+static int nandi_scan_bad_block_markers_block(struct nandi_controller *nandi,
+                                             uint32_t block)
+
+{
+       struct mtd_info *mtd = &nandi->info.mtd;
+       struct nand_chip *chip = mtd->priv;
+       uint32_t pages_per_block = mtd->erasesize >> nandi->page_shift;
+       uint32_t page = block << (nandi->block_shift - nandi->page_shift);
+
+       if (nandi_scan_bad_block_markers_page(nandi, page))
+               return 1;
+
+       if ((chip->bbt_options & NAND_BBT_SCAN2NDPAGE) &&
+           nandi_scan_bad_block_markers_page(nandi, page + 1))
+               return 1;
+
+       if ((chip->bbt_options & NAND_BBT_SCANLASTPAGE) &&
+           nandi_scan_bad_block_markers_page(nandi,
+                                             page + pages_per_block - 1))
+               return 1;
+
+       return 0;
+}
+
 /* Populate IBBT BCH Header */
 static void bch_fill_ibbt_header(struct nandi_controller *nandi,
                                 struct nand_ibbt_bch_header *ibbt_header,
@@ -1133,6 +1193,8 @@ static void nandi_set_mtd_defaults(struct 
nandi_controller *nandi,
        chip->ecc.layout = &info->ecclayout;
        chip->options |= NAND_NO_SUBPAGE_WRITE;
 
+       chip->bbt_options |= NAND_BBT_USE_FLASH;
+
        /* mtd_info */
        mtd->owner = THIS_MODULE;
        mtd->type = MTD_NANDFLASH;
-- 
1.8.3.2

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