mtd: nand: raw: allow to disable unneeded ECC layouts

Each ECC layout consumes about 2984 bytes in the .data section. Allow
to disable the default ECC layouts if a driver is known to provide its
own ECC layout.
Signed-off-by: NStefan Agner <stefan.agner@toradex.com>
Reviewed-by: NLukasz Majewski <lukma@denx.de>
Reviewed-by: NMiquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/Kconfig

@@ -9,6 +9,12 @@ config SYS_NAND_SELF_INIT
 	  This option, if enabled, provides more flexible and linux-like
 	  NAND initialization process.
 
+config SYS_NAND_DRIVER_ECC_LAYOUT
+	bool
+	help
+	  Omit standard ECC layouts to safe space. Select this if your driver
+	  is known to provide its own ECC layout.
+
 config NAND_ATMEL
 	bool "Support Atmel NAND controller"
 	imply SYS_NAND_USE_FLASH_BBT
@@ -81,6 +87,7 @@ config NAND_OMAP_ELM
 config NAND_VF610_NFC
 	bool "Support for Freescale NFC for VF610"
 	select SYS_NAND_SELF_INIT
+	select SYS_NAND_DRIVER_ECC_LAYOUT
 	imply CMD_NAND
 	help
 	  Enables support for NAND Flash Controller on some Freescale

drivers/mtd/nand/raw/nand_base.c

@@ -47,6 +47,7 @@
 #include <linux/errno.h>
 
 /* Define default oob placement schemes for large and small page devices */
+#ifdef CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT
 static struct nand_ecclayout nand_oob_8 = {
 	.eccbytes = 3,
 	.eccpos = {0, 1, 2},
@@ -89,6 +90,7 @@ static struct nand_ecclayout nand_oob_128 = {
 		{.offset = 2,
 		 .length = 78} }
 };
+#endif
 
 static int nand_get_device(struct mtd_info *mtd, int new_state);
 
@@ -4339,6 +4341,7 @@ int nand_scan_tail(struct mtd_info *mtd)
 	 */
 	if (!ecc->layout && (ecc->mode != NAND_ECC_SOFT_BCH)) {
 		switch (mtd->oobsize) {
+#ifdef CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT
 		case 8:
 			ecc->layout = &nand_oob_8;
 			break;
@@ -4351,6 +4354,7 @@ int nand_scan_tail(struct mtd_info *mtd)
 		case 128:
 			ecc->layout = &nand_oob_128;
 			break;
+#endif
 		default:
 			pr_warn("No oob scheme defined for oobsize %d\n",
 				   mtd->oobsize);