Slow HAB verification in SPL

per_orback — Wed, 09 Sep 2020 07:44:54 GMT

Hi, I am working in a project where the boot up time is a critical issue. The project is built around IMX6DL and we are using HAB. The boot sequence is SPL->u-boot->FIT-image, u-boot version is fslc-2018.11. We experience that the image verification of the u-boot image from the SPL is very slow. Around 800ms only for the function call to imx_hab_authenticate_image(). The verification of the FIT image from u-boot is much faster, almost 500ms faster.

According to the reference manual the MMU and caches are enabled i ROM for faster image verification but then disabled again after the authentication of the SPL image. The MMU and caches seems to be enabled again in the u-boot code which meas these will be disable when the SPL is running.

Can this be the cause of the slow u-boot verification in SPL? Do any one knows how to enable the MMU and caches in SPL code or can point me to a available patch?

Best regards,
Per Örbäck

Re: Slow HAB verification in SPL

Yuri — Thu, 10 Sep 2020 04:57:59 GMT

@per_orback
Hello,

This is correct - the boot ROM enables caches to authenticate images, and then disables prior
to jumping to the loaded image. The intent is MMU/Caches to be disabled when the loaded image
takes control. This ensures the user code is responsible for configuring its environment.
NXP Linux BSP does not use SPL for i.MX6. For i.MX 6 and i.MX 7, the boot image uses only
the U-Boot bootloader.

Regards,
Yuri.

topic Slow HAB verification in SPL in i.MX Processors

Slow HAB verification in SPL

Re: Slow HAB verification in SPL