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>
ELM hardware engine which is used for ECC error detection, is present on all
latest OMAP SoC (like OMAP4xxx, OMAP5xxx, DRA7xxx, AM33xx, AM43xx). Thus ELM
driver should be moved to common drivers/mtd/nand/ folder so that all SoC
having on-chip ELM hardware engine can re-use it.
This patch has following changes:
- mv arch/arm/include/asm/arch-am33xx/elm.h arch/arm/include/asm/omap_elm.h
- mv arch/arm/cpu/armv7/am33xx/elm.c drivers/mtd/nand/omap_elm.c
- update Makefiles
- update #include <asm/elm.h>
- add CONFIG_NAND_OMAP_ELM to compile driver/mtd/nand/omap_elm.c
and include in all board configs using AM33xx SoC platform.
Signed-off-by: Pekon Gupta <pekon@ti.com>
