Re: [PATCH] mtd: spi-nor: Fix quad-enable for flashes with QER bit in SR1

["Michael Walle" <mwalle@kernel.org>]

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On Fri Sep 11, 2026 at 10:55 AM CEST, Miquel Raynal wrote:
> Some flashes (eg. from Macronix) do set BFPT_DWORD15_QER_SR1_BIT6, which
> means they do not have an SR2 to read from/write to. The new generic QE
> helper was supposed to accommodate this situation but in the last version
> that got merged, parts of that specific handling has been moved to a
> more contained location, swp.c (which needed most of the extra code),
> yet the Macronix case has been forgotten about in that generic QE
> handling helper. Booting with such flashes will always fail probing.
>
> Fix the situation by making sure we do not attempt to read SR2 if the QE
> bit is in SR1.
>
> Reported-by: Jon Hunter <jonathanh@nvidia.com>
> Closes: https://lore.kernel.org/linux-mtd/178876719232.3543902.14451625037676421254.b4-ty@b4/T/#m5bc4ba6776436f2870ced0eb5789d229037ad840
> Fixes: 63489002d397 ("mtd: spi-nor: Refactor Read Status/Write Status support")
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  drivers/mtd/spi-nor/core.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index e2b6efafdd8d..ac909dfb9657 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -985,7 +985,10 @@ static int spi_nor_generic_quad_enable(struct spi_nor *nor)
>  	if (!qe_mask[0] && !qe_mask[1])
>  		return 0;
>  
> -	ret = spi_nor_read_sr1_and_sr2(nor, sr);
> +	if (qe_mask[0])
> +		ret = spi_nor_read_sr1(nor, sr);
> +	else
> +		ret = spi_nor_read_sr1_and_sr2(nor, sr);

Shouldn't that be the other way around?

+	if (qe_mask[1])
+		ret = spi_nor_read_sr1_and_sr2(nor, sr);
+	else
+		ret = spi_nor_read_sr1(nor, sr);

I know qe_mask won't be spread across two SRs. Just to be
correct and make it easier to grok.

-michael

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