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

[Heiko Schocher]

Hello Roger,

On 15.11.23 12:09, Roger Quadros wrote:
> 
> 
> 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.

Yes, I played with setting up stuff in drivers/mtd/nand/raw/am335x_spl_bch.c
but failed ...

If I can help you testing, feel free to ask!

bye,
Heiko
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