Re: [PATCH v9 18/18] mtd: spi-nor: run controller optimization before dirmap creation

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The validated tuning frequency (`nor->max_read_op.max_freq`) is indiscriminately applied to all read operations constructed via `spi_nor_spimem_get_read_op()`. This incorrectly forces low-speed alternative read commands (such as OTP reads) to execute at the high-speed PHY-calibrated frequency.
--

commit 6decf5586ab8fae3319b12bc93ad82202b53b090
Author: Santhosh Kumar K <s-k6@ti.com>

mtd: spi-nor: run controller optimization before dirmap creation

This commit runs controller optimization before creating dirmaps so the
validated frequency is available at dirmap construction time. It stores the
configured read op template and propagates the calibrated rate into regular
read ops. Optimization failure is non-fatal.

> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index b683c077a233d..2efcdc7f637fb 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -216,6 +216,9 @@ static struct spi_mem_op spi_nor_spimem_get_read_op(struct spi_nor *nor)
>  	if (spi_nor_protocol_is_dtr(nor->read_proto))
>  		op.dummy.nbytes *= 2;
>  
> +	/* Propagate the validated frequency; zero before tuning. */
> +	op.max_freq = nor->max_read_op.max_freq;
> +

[Severity: High]
Does applying the tuned frequency to all read operations cause issues for
lower-speed commands?

When reading the OTP area via the MTD API, spi_nor_otp_read_secr() in
drivers/mtd/spi-nor/otp.c temporarily changes the opcode and sets the
protocol to 1-1-1, then calls spi_nor_read_data():

drivers/mtd/spi-nor/otp.c:spi_nor_otp_read_secr() {
    ...
    nor->read_opcode = SPINOR_OP_RSECR;
    nor->read_proto = SNOR_PROTO_1_1_1;

    ret = spi_nor_read_data(nor, addr, len, buf);
    ...
}

Because spi_nor_spimem_get_read_op() unconditionally sets op.max_freq to the
high-speed PHY-calibrated frequency, will this force the 1-1-1 OTP read to
execute at an inappropriately high clock speed and potentially fail or
return corrupted data?

>  	return op;
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260825171737.776052-1-s-k6@ti.com?part=18