mxc_nand: Allow flash based bbt

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/plat-mxc/include/mach/mxc_nand.h

@@ -22,6 +22,7 @@
 
 struct mxc_nand_platform_data {
 	int width;	/* data bus width in bytes */
-	int hw_ecc;	/* 0 if supress hardware ECC */
+	int hw_ecc:1;	/* 0 if supress hardware ECC */
+	int flash_bbt:1; /* set to 1 to use a flash based bbt */
 };
 #endif /* __ASM_ARCH_NAND_H */

drivers/mtd/nand/mxc_nand.c

@@ -648,6 +648,33 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 	}
 }
 
+/*
+ * 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 @@ static int __init mxcnd_probe(struct platform_device *pdev)
 	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;