mtd: nand: omap: add CONFIG_NAND_OMAP_ECCSCHEME for selection of ecc-scheme

This patch adds new CONFIG_NAND_OMAP_ECCSCHEME, replacing other distributed
CONFIG_xx used for selecting NAND ecc-schemes.
This patch aims at solving following issues.

1) Currently ecc-scheme is tied to SoC platform, which prevents user to select
   other ecc-schemes also supported in hardware. like;
 - most of OMAP3 SoC platforms use only 1-bit Hamming ecc-scheme, inspite
   the fact that they can use higher ecc-schemes like 8-bit ecc-schemes with
   software based error detection (OMAP_ECC_BCH4_CODE_HW_DETECTION_SW).
 - most of AM33xx SoC plaforms use 8-bit BCH ecc-scheme for now, but hardware
   supports BCH16 ecc-scheme also.

2) Different platforms use different CONFIG_xx to select ecc-schemes, which
   adds confusion for user while migrating platforms.
 - *CONFIG_NAND_OMAP_ELM* which enables ELM hardware engine, selects only
    8-bit BCH ecc-scheme with h/w based error-correction (OMAP_ECC_BCH8_CODE_HW)
    whereas ELM hardware engine supports other ecc-schemes also like; BCH4,
    and BCH16 (in future).
 - *CONFIG_NAND_OMAP_BCH8* selects 8-bit BCH ecc-scheme with s/w based error
    correction (OMAP_ECC_BCH8_CODE_HW_DETECTION_SW).
 - *CONFIG_SPL_NAND_SOFTECC* selects 1-bit Hamming ecc-scheme using s/w library

Thus adding new *CONFIG_NAND_OMAP_ECCSCHEME* de-couples ecc-scheme dependency
on SoC platform and NAND driver. And user can select ecc-scheme independently
foreach board.
However, selection some hardware based ecc-schemes (OMAP_ECC_BCHx_CODE_HW) still
depends on presence of ELM hardware engine on SoC. (Refer doc/README.nand)

Signed-off-by: Pekon Gupta <pekon@ti.com>

1 files changed, 4 insertions, 9 deletions

diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index e6b289dec8..5e7e6b3375 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -1004,18 +1004,13 @@ int board_nand_init(struct nand_chip *nand)
 	nand->ecc.layout = &omap_ecclayout;
 
 	/* select ECC scheme */
-#if defined(CONFIG_NAND_OMAP_ELM)
-	err = omap_select_ecc_scheme(nand, OMAP_ECC_BCH8_CODE_HW,
+#if defined(CONFIG_NAND_OMAP_ECCSCHEME)
+	err = omap_select_ecc_scheme(nand, CONFIG_NAND_OMAP_ECCSCHEME,
 			CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE);
-#elif defined(CONFIG_NAND_OMAP_BCH8)
-	err = omap_select_ecc_scheme(nand, OMAP_ECC_BCH8_CODE_HW_DETECTION_SW,
-			CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE);
-#elif !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_NAND_SOFTECC)
+#else
+	/* pagesize and oobsize are not required to configure sw ecc-scheme */
 	err = omap_select_ecc_scheme(nand, OMAP_ECC_HAM1_CODE_SW,
 			0, 0);
-#else
-	err = omap_select_ecc_scheme(nand, OMAP_ECC_HAM1_CODE_HW,
-			CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE);
 #endif
 	if (err)
 		return err;