7.40.1.Boot Sequence

For AARCH32:

Bootrom –> BL1/BL2 –> BL32 –> BL33 –> Linux kernel

For AARCH64:

Bootrom –> BL1/BL2 –> BL31 –> BL33 –> Linux kernel

BL1/2 and BL33 can currently be supplied from either:- Coreboot + Depthcharge- U-Boot - either separately as TPL+SPL or only SPL

7.40.2.How to build

Rockchip SoCs expect TF-A’s BL31 (AARCH64) or BL32 (AARCH32) to getintegrated with other boot software like U-Boot or Coreboot, so onlythese images need to get build from the TF-A repository.

For AARCH64 architectures the build command looks like

make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3399 bl31

while AARCH32 needs a slightly different command

make ARCH=aarch32 CROSS_COMPILE=arm-linux-gnueabihf- PLAT=rk3288 AARCH32_SP=sp_min bl32

Both need replacing the PLAT argument with the platform from above youwant to build for and the CROSS_COMPILE argument with you cross-compilation toolchain.

7.40.3.How to deploy

Both upstream U-Boot and Coreboot projects contain instructions on whereto put the built images during their respective build process.So after successfully building TF-A just follow their build instructionsto continue.