better setting of nand ecc step size

src/arch/arm/boot/dts/elphel393-zynq-base.dtsi

@@ -313,7 +313,6 @@
 				compatible = "arm,pl353-nand-r2p1";
 				reg = <0 0 0x1000000>;
                                 nand-ecc-mode = "on-die";
-                                nand-ecc-step-size = <2048>;
 				/*arm,nand-clk-freq-hz = <0x5f5e100>;*/
 				arm,nand-width = <0x8>;
 				arm,nand-cycle-t0 = <0x4>;

src/drivers/mtd/nand/raw/nand_micron.c

@@ -744,10 +744,7 @@ static int micron_nand_init(struct nand_chip *chip)
 					  &micron_nand_on_die_8_ooblayout_ops);
 
 		chip->ecc.bytes = chip->ecc_strength_ds * 2;
-		// this is already read from the device tree
-		if (!chip->ecc.size){
 		chip->ecc.size = 512;
-		}
 		chip->ecc.strength = chip->ecc_strength_ds;
 		chip->ecc.algo = NAND_ECC_BCH;
 		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;

src/drivers/mtd/nand/raw/pl353_nand.c

@@ -1341,7 +1341,11 @@ static int pl353_nand_probe(struct platform_device *pdev)
 	xnfc->buswidth = val;
 	chip->chip_delay = 30;
 	/* Set the device option and flash width */
-	chip->options = NAND_BUSWIDTH_AUTO;
+	// old:
+	//chip->options = NAND_BUSWIDTH_AUTO;
+	// new: MT29F8G08ADBDAH4 does not support subpage write,
+	//      setting here, will change later
+	chip->options = NAND_BUSWIDTH_AUTO | NAND_NO_SUBPAGE_WRITE;
 	chip->bbt_options = NAND_BBT_USE_FLASH;
 	platform_set_drvdata(pdev, xnfc);
 	chip->setup_data_interface = pl353_setup_data_interface;