mtd: nand: sunxi: Support ECC maximization

Setup the maximum ECC config when NAND_ECC_MAXIMIZE is set.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/sunxi_nand.c

@@ -1787,6 +1787,35 @@ static int sunxi_nand_hw_common_ecc_ctrl_init(struct mtd_info *mtd,
 	int ret;
 	int i;
 
+	if (ecc->options & NAND_ECC_MAXIMIZE) {
+		int bytes;
+
+		ecc->size = 1024;
+		nsectors = mtd->writesize / ecc->size;
+
+		/* Reserve 2 bytes for the BBM */
+		bytes = (mtd->oobsize - 2) / nsectors;
+
+		/* 4 non-ECC bytes are added before each ECC bytes section */
+		bytes -= 4;
+
+		/* and bytes has to be even. */
+		if (bytes % 2)
+			bytes--;
+
+		ecc->strength = bytes * 8 / fls(8 * ecc->size);
+
+		for (i = 0; i < ARRAY_SIZE(strengths); i++) {
+			if (strengths[i] > ecc->strength)
+				break;
+		}
+
+		if (!i)
+			ecc->strength = 0;
+		else
+			ecc->strength = strengths[i - 1];
+	}
+
 	if (ecc->size != 512 && ecc->size != 1024)
 		return -EINVAL;