[PATCH] mtd: nand: pxa3xx: Incorrect bitflip return on page read

[Chris Packham]

On Sun, Apr 28, 2024 at 4:15 AM Ravi Minnikanti <rminnikanti at marvell.com> wrote:
>
> Once a page is read with higher bitflips all subsequent reads
> are returning the same bitflip value even though they have none.
> max_bitflip variable is not being reset to 0 across page reads.
>
> This is causing problems like incorrectly
> marking erase blocks bad by UBI and causing read failures.
>
> Verified the change with both MTD reads and UBI.
> This change is inline with other NFC drivers.
>
> Sample error log where a block is marked bad incorrectly:
>
> ubi0: fixable bit-flip detected at PEB 125
> ubi0: run torture test for PEB 125
> ubi0: fixable bit-flip detected at PEB 125
> ubi0 error: torture_peb: read problems on freshly erased PEB 125,
> must be bad
> ubi0 error: erase_worker: failed to erase PEB 125, error -5
> ubi0: mark PEB 125 as bad
>
> Signed-off-by: rminnikanti <rminnikanti at marvell.com>

Looks good to me

Reviewed-by: Chris Packham <judge.packham at gmail.com>

> ---
>  drivers/mtd/nand/raw/pxa3xx_nand.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mtd/nand/raw/pxa3xx_nand.c b/drivers/mtd/nand/raw/pxa3xx_nand.c
> index 1d9a6d107b..d2a4faad56 100644
> --- a/drivers/mtd/nand/raw/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/raw/pxa3xx_nand.c
> @@ -800,6 +800,11 @@ static void prepare_start_command(struct pxa3xx_nand_info *info, int command)
>         info->ecc_err_cnt       = 0;
>         info->ndcb3             = 0;
>         info->need_wait         = 0;
> +       /*
> +        * Reset max_bitflips to zero. Once command is complete,
> +        * max_bitflips for this READ is returned in ecc.read_page()
> +        */
> +       info->max_bitflips      = 0;
>
>         switch (command) {
>         case NAND_CMD_READ0:
> --
> 2.17.1