[PATCH 05/10] arm: stm32mp: bsec: Do not skip .probe() for SPL

[Patrick DELAUNAY]

Hi

On 8/26/21 11:42 PM, Alexandru Gagniuc wrote:

> stm32mp_bsec_probe() was skipped for TFABOOT and SPL_BUILD. The idea
> of skipping probe() is that we can't access BSEC from the normal
> world. This is true with TFABOOT. However, in SPL, we are in the
> secure world, so skipping probe is incorrect. In fact, SPL is not
> even built when TFABOOT is selected.
>
> Thus, only skip probe with TFABOOT, but not SPL_BUILD.
>
> Signed-off-by: Alexandru Gagniuc <mr.nuke.me at gmail.com>
> ---
>   arch/arm/mach-stm32mp/bsec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-stm32mp/bsec.c b/arch/arm/mach-stm32mp/bsec.c
> index fe39bd80cf..a02d19c1b9 100644
> --- a/arch/arm/mach-stm32mp/bsec.c
> +++ b/arch/arm/mach-stm32mp/bsec.c
> @@ -506,7 +506,7 @@ static int stm32mp_bsec_probe(struct udevice *dev)
>   	 * only executed in U-Boot proper when TF-A is not used
>   	 */
>   
> -	if (!IS_ENABLED(CONFIG_TFABOOT) && !IS_ENABLED(CONFIG_SPL_BUILD)) {
> +	if (!IS_ENABLED(CONFIG_TFABOOT)) {
>   		plat = dev_get_plat(dev);
>   
>   		for (otp = 57; otp <= BSEC_OTP_MAX_VALUE; otp++)


in this part the dirver don't skip the BSEC probe (still return 0)

BUT the BSEC driver skip only the shadow of the OTP

=> this initialisation is necessary only one time to save time

a/ for TF-A boot it is done in TF-A

b/ for basic boot (SPL + U-Boot) is only done in U-Boot proper (because 
is not mandatory in SPL

and the U-Boot execution was faster - before the data cache activation 
in SPL)


With this patch the copy of the OTP in shadow memory is done 2 times

1/ in SPL (BSEC probe) = with CONFIG_SPL_BUILD

2/ in U-Boot (BSEC probe)

see comment:

     /*
      * update unlocked shadow for OTP cleared by the rom code
      * only executed in U-Boot proper when TF-A is not used
      */


but for falcon mode, as the Linux driver expected the OTP are shadowed,

the operation need to be done in SPL and in U-Boot proper

I propose


     /*

      * update unlocked shadow for OTP cleared by the rom code

-     * only executed in U-Boot proper when TF-A is not used

+     * only executed in U-Boot SPL, it is done in TF-A when used

      */

-	if (!IS_ENABLED(CONFIG_TFABOOT) && !IS_ENABLED(CONFIG_SPL_BUILD)) {
+	if (IS_ENABLED(CONFIG_SPL_BUILD)) {


Regards

Patrick