Re: [PATCH v4 03/17] mtd: rawnand: sunxi: propagate page-setup and erased-check errors

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The patch introduces a regression for small-page NANDs by explicitly propagating errors from `nand_change_read_column_op()`, which unconditionally returns `-ENOTSUPP` when `mtd->writesize <= 512`.
--

commit 63fba1d4fa0b9df218cee82050011ec93e712247
Author: James Hilliard <james.hilliard1@gmail.com>

mtd: rawnand: sunxi: propagate page-setup and erased-check errors

This commit stops before starting PIO or DMA transfers when page setup fails
and shares the erased-chunk fallback between PIO and DMA. It routes PIO page
and subpage error exits through ECC disable before returning the transfer
error.

> diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c
> index 172c7c4b0ba6d..d5d8d383b6d12 100644
> --- a/drivers/mtd/nand/raw/sunxi_nand.c
> +++ b/drivers/mtd/nand/raw/sunxi_nand.c
[ ... ]
> @@ -1067,6 +1067,40 @@ static void sunxi_nfc_hw_ecc_update_stats(struct nand_chip *nand,
>  	}
>  }
>  
> +/*
> + * Return 1 for an erased chunk or 0 for an uncorrectable chunk, with ECC
> + * statistics updated in either case. Negative values report transport errors.
> + */
> +static int sunxi_nfc_hw_ecc_read_error(struct nand_chip *nand,
> +				       u8 *data, int data_off,
> +				       u8 *oob, int oob_off,
> +				       unsigned int user_data_sz,
> +				       unsigned int *max_bitflips)
> +{
> +	struct nand_ecc_ctrl *ecc = &nand->ecc;
> +	unsigned int oob_len = ecc->bytes + user_data_sz;
> +	int ret;
> +
> +	/* Check the physical representation for bitflips in erased pages. */
> +	if (nand->options & NAND_NEED_SCRAMBLING) {
> +		ret = nand_change_read_column_op(nand, data_off, data,
> +						 ecc->size, false);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = nand_change_read_column_op(nand, oob_off, oob, oob_len, false);
> +	if (ret)
> +		return ret;

[Severity: High]
Will this introduce a regression for small-page NANDs?

When an ECC error is detected, the driver attempts an erased chunk check via
sunxi_nfc_hw_ecc_read_error(), which calls nand_change_read_column_op().

Looking at nand_change_read_column_op() in drivers/mtd/nand/raw/nand_base.c,
it does not support column changes for small-page NANDs and unconditionally
returns -ENOTSUPP:

drivers/mtd/nand/raw/nand_base.c:nand_change_read_column_op() {
        ...
        /* Small page NANDs do not support column change. */
        if (mtd->writesize <= 512)
                return -ENOTSUPP;
        ...
}

By explicitly propagating this error, it appears read operations on erased
pages, bad block scans, and OOB data reads on small-page NANDs will now abort
with a transport error (-ENOTSUPP) instead of correctly reporting ECC errors
(-EBADMSG) or processing erased chunks. Prior to this patch, the error from
nand_change_read_column_op() was safely ignored in this path, allowing the
driver to fall back to reporting an uncorrectable ECC error gracefully.

> +
> +	ret = nand_check_erased_ecc_chunk(data, ecc->size, oob, oob_len, NULL, 0,
> +					  ecc->strength);
> +
> +	sunxi_nfc_hw_ecc_update_stats(nand, max_bitflips, ret);
> +
> +	return ret >= 0;
> +}
> +

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260912-submit-sunxi-nand-vendor-oob-layout-v1-v4-0-4a64bed94229@gmail.com?part=3