[U-Boot] Building SPL version of u-boot (imx6 Sabre Lite)

[Vincent]

Hi,
I am currently experimenting with Trustzone on Freescale boards,
having Android/Linux in the normal world (NW) and a custom baremetal
mini-os in the secure world (SW).

My first board was a sabre imx6Q-SDP [1]. In order to boot both OS, we
used the mx6sabresd_spl_defconfig configuration (with a few patches to
support our system) so the SPL (in Secure mode) loads u-boot/Linux and
our OS in memory, gives control to our OS, which at some point makes a
switch to NW and start the second u-boot (which will start Linux).

I am now trying to port our work to another imx6 board [2] based on a
imx6Q-lite, using Boundary Devices clone of u-boot [3]. In this
setting, u-boot starts a Linux in the SW. I made a few attempts at
patching u-boot to start Linux in NW, but I failed.

Since neither in the mainline u-boot nor their patched version
provides a "SPL" configuration for the sabre lite, I am looking for a
way to build it myself. Is there a roadmap to build a "SPL"
configuration from a "normal" configuration in u-boot ? Or is there a
way to configure u-boot so that Linux is started in the NW instead of
the SW ?

Best regards,
Vincent



[1]: http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors-based-on-arm-cores/i.mx-6-processors/i.mx6qp/sabre-platform-for-smart-devices-reference-design-based-on-the-i.mx-6-series:RDIMX6SABREPLAT

[2]: https://boundarydevices.com/product/sabre-lite-imx6-sbc/

[3]: https://github.com/boundarydevices/u-boot-imx6 nitrogen6q_defconfig