[PATCH 03/16] arm: stm32mp: reset to default environment when serial# change

[Wolfgang Denk]

Dear Patrick,

In message <20200331180330.3.I8f6df6d28ce5b4b601ced711af3699d95e1576fb at changeid> you wrote:
> Serial number is first checked and, in case of mismatch, all
> environment variables are reset to their default value.
>
> This patch allows to detect that environment is saved in a removable
> device, as a SD card, and reused on a other board, potentially with
> incompatible variables.
>
> Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
> ---
>
>  arch/arm/mach-stm32mp/cpu.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
> index 9aa5794334..365c2aa4f7 100644
> --- a/arch/arm/mach-stm32mp/cpu.c
> +++ b/arch/arm/mach-stm32mp/cpu.c
> @@ -511,8 +511,9 @@ __weak int setup_mac_address(void)
>  		return -EINVAL;
>  	}
>  	pr_debug("OTP MAC address = %pM\n", enetaddr);
> -	ret = !eth_env_set_enetaddr("ethaddr", enetaddr);
> -	if (!ret)
> +
> +	ret = eth_env_set_enetaddr("ethaddr", enetaddr);
> +	if (ret)
>  		pr_err("Failed to set mac address %pM from OTP: %d\n",
>  		       enetaddr, ret);

This is an unrelated and totally undocumented change.  Please split
into separate commit.


> +
> +	if (serial_env) {
> +		if (!strcmp(serial_string, serial_env))
> +			return 0;
> +		/* For invalid enviromnent (serial# change), reset to default */
> +		env_set_default("serial number mismatch", 0);
> +	}

Resetting the enviropnment to the defaults means you drop all
setting sa user may have made.  This is a very bad move - as a user
I find such things completely unacceptable.  If I make any changes,
they must never ever be killed without my explicit confirmation.

I strongly advice against such a method. Please drop that.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"You ain't experienced..." "Well, nor are you." "That's true. But the
point is ... the point is ... the point is we've been not experienced
for a lot longer than you. We've got  a  lot  of  experience  of  not
having any experience."           - Terry Pratchett, _Witches Abroad_