[PATCH] mtd: rawnand: omap_gpmc: fix BCH8 HW based correction

[Roger Quadros]

On 15/11/2023 07:40, Heiko Schocher wrote:
> commit 04fcd2587321 ("mtd: rawnand: omap_gpmc: Fix BCH6/16 HW based correction")
> 
> broke AM335x based boards booting from NAND with ECC BCH8 code.
> 
> Use omap_enable_hwecc() instead of omap_enable_hwecc_bch()
> in SPL restores correct SPL nand_read_page functionality.
> 
> Tested on draco thuban board.
> 
> Signed-off-by: Heiko Schocher <hs at denx.de>
> 
> ---
> fix NAND boot for BCH8 based TI AM335x boards
> 
> Fix is based on series from Enrico:
> 
> https://lists.denx.de/pipermail/u-boot/2023-November/536793.html
> 
> and fixes NAND boot for the draco thuban board. But this patch
> apply also without the patches from above patchseries, see
> azure build:
> 
> https://dev.azure.com/hs0298/hs/_build/results?buildId=111&view=results
> 
> which is clean.
> 
> Above commit seems to change only U-Boot code and did not
> adapt am335x_spl_bch.c, which breaks nand_read_page in SPL
> code for AM335x based boards. So use in SPL "old" hw setup
> and reading page from NAND in SPL works again.
> 
> 
>  drivers/mtd/nand/raw/omap_gpmc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/omap_gpmc.c b/drivers/mtd/nand/raw/omap_gpmc.c
> index 1a5ed0de31..c9b66dadbd 100644
> --- a/drivers/mtd/nand/raw/omap_gpmc.c
> +++ b/drivers/mtd/nand/raw/omap_gpmc.c
> @@ -983,7 +983,11 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
>  		nand->ecc.strength	= 8;
>  		nand->ecc.size		= SECTOR_BYTES;
>  		nand->ecc.bytes		= 14;
> +#if defined(CONFIG_SPL_BUILD)
> +		nand->ecc.hwctl		= omap_enable_hwecc;

I don't think this is correct. omap_enable_hwecc does not setup
the BCH settings and should be used only for 1-bit ECC i.e. OMAP_ECC_HAM1_CODE_*

I'm sure it will break the boards not using
CONFIG_SPL_NAND_AM33XX_BCH which is
pretty much most TI boards that are not AM335x.

Now, I need to identify why AM335x NAND is broken.

> +#else
>  		nand->ecc.hwctl		= omap_enable_hwecc_bch;
> +#endif
>  		nand->ecc.correct	= omap_correct_data_bch;
>  		nand->ecc.calculate	= omap_calculate_ecc_bch;
>  		nand->ecc.read_page	= omap_read_page_bch;

-- 
cheers,
-roger