mxc_nand: Allow flash based bbt

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 2e3f3fb..044a574 100644
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -648,6 +648,33 @@
 	}
 }
 
+/*
+ * The generic flash bbt decriptors overlap with our ecc
+ * hardware, so define some i.MX specific ones.
+ */
+static uint8_t bbt_pattern[] = { 'B', 'b', 't', '0' };
+static uint8_t mirror_pattern[] = { '1', 't', 'b', 'B' };
+
+static struct nand_bbt_descr bbt_main_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+	    | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+	.offs = 0,
+	.len = 4,
+	.veroffs = 4,
+	.maxblocks = 4,
+	.pattern = bbt_pattern,
+};
+
+static struct nand_bbt_descr bbt_mirror_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+	    | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+	.offs = 0,
+	.len = 4,
+	.veroffs = 4,
+	.maxblocks = 4,
+	.pattern = mirror_pattern,
+};
+
 static int __init mxcnd_probe(struct platform_device *pdev)
 {
 	struct nand_chip *this;
@@ -786,6 +813,13 @@
 	if (pdata->width == 2)
 		this->options |= NAND_BUSWIDTH_16;
 
+	if (pdata->flash_bbt) {
+		this->bbt_td = &bbt_main_descr;
+		this->bbt_md = &bbt_mirror_descr;
+		/* update flash based bbt */
+		this->options |= NAND_USE_FLASH_BBT;
+	}
+
 	/* first scan to find the device and get the page size */
 	if (nand_scan_ident(mtd, 1)) {
 		err = -ENXIO;