On Tue, 4 Sep 2018 11:14:38 +0200
Boris Brezillon <boris.brezillon@xxxxxxxxxxx> wrote:
> Apparently ECC bytes are not ordered as expected by nand_correct_data()
> in the ecc_calc buffer which leads to invalid bitflip correction when
> an ECC error is detected (can be reproduced with 'nandbiterrs -i').
>
> Re-ordering ECC bytes seems to fix the problem.
>
> While at it, get rid of the useless u8 cast.
>
> Fixes: 6c009ab89a21 ("mtd: generic FSMC NAND MTD driver")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
> ---
> drivers/mtd/nand/raw/fsmc_nand.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/fsmc_nand.c b/drivers/mtd/nand/raw/fsmc_nand.c
> index f418236fa020..c79f8e965b38 100644
> --- a/drivers/mtd/nand/raw/fsmc_nand.c
> +++ b/drivers/mtd/nand/raw/fsmc_nand.c
> @@ -440,9 +440,9 @@ static int fsmc_read_hwecc_ecc1(struct mtd_info *mtd, const uint8_t *data,
> uint32_t ecc_tmp;
>
> ecc_tmp = readl_relaxed(host->regs_va + ECC1);
> - ecc[0] = (uint8_t) (ecc_tmp >> 0);
> - ecc[1] = (uint8_t) (ecc_tmp >> 8);
> - ecc[2] = (uint8_t) (ecc_tmp >> 16);
> + ecc[0] = ecc_tmp >> 8;
> + ecc[1] = ecc_tmp;
> + ecc[2] = ecc_tmp >> 16;
Hm, looks like there's a Kconfig option (CONFIG_MTD_NAND_ECC_SMC) to let
nand_ecc_correct() swap those 2 bytes for us, but it's clearly not a
good thing to take this decision based on a Kconfig option (does not
work if you want the same kernel to be used on various platforms).
I'll come up with a better solution.
