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

[Patrice CHOTARD]

Hi Patrick   

On 3/31/20 6:04 PM, Patrick Delaunay 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);
>  #endif
> @@ -522,13 +523,13 @@ __weak int setup_mac_address(void)
>  
>  static int setup_serial_number(void)
>  {
> +	char *serial_env;
>  	char serial_string[25];
>  	u32 otp[3] = {0, 0, 0 };
>  	struct udevice *dev;
>  	int ret;
>  
> -	if (env_get("serial#"))
> -		return 0;
> +	serial_env = env_get("serial#");
>  
>  	ret = uclass_get_device_by_driver(UCLASS_MISC,
>  					  DM_GET_DRIVER(stm32mp_bsec),
> @@ -542,6 +543,15 @@ static int setup_serial_number(void)
>  		return ret;
>  
>  	sprintf(serial_string, "%08X%08X%08X", otp[0], otp[1], otp[2]);
> +
> +	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);
> +	}
> +
> +	/* save serial number */
>  	env_set("serial#", serial_string);
>  
>  	return 0;
> @@ -549,9 +559,9 @@ static int setup_serial_number(void)
>  
>  int arch_misc_init(void)
>  {
> +	setup_serial_number();
>  	setup_boot_mode();
>  	setup_mac_address();
> -	setup_serial_number();
>  
>  	return 0;
>  }

Reviewed-by: Patrice Chotard <patrice.chotard at st.com>

Thanks