2.5. TC Total Compute Platform

Some of the features of TC platform referenced in TF-A include:

A System Control Processor to abstract power and system management tasks away from application processors. The RAM firmware for SCP is included in the TF-A FIP and is loaded by AP BL2 from FIP in flash to SRAM for copying by SCP (SCP has access to AP SRAM).
GICv4
Trusted Board Boot
SCMI
MHUv2

Currently, the main difference between TC0 (TARGET_PLATFORM=0) and TC1 (TARGET_PLATFORM=1) platforms w.r.t to TF-A is the CPUs supported. TC0 has support for Cortex A510, Cortex A710 and Cortex X2, while TC1 has support for Cortex A510, Cortex Makalu and Cortex Makalu ELP Arm CPUs.

2.5.1. Boot Sequence

The execution begins from SCP_BL1. SCP_BL1 powers up the AP which starts executing AP_BL1 and then executes AP_BL2 which loads the SCP_BL2 from FIP to SRAM. The SCP has access to AP SRAM. The address and size of SCP_BL2 is communicated to SCP using SDS. SCP copies SCP_BL2 from SRAM to its own RAM and starts executing it. The AP then continues executing the rest of TF-A stages including BL31 runtime stage and hands off executing to Non-secure world (u-boot).

2.5.1.1. Build Procedure (TF-A only)

Obtain arm toolchain. Set the CROSS_COMPILE environment variable to point to the toolchain folder.

Build TF-A:

make PLAT=tc BL33=<path_to_uboot.bin> \
SCP_BL2=<path_to_scp_ramfw.bin> TARGET_PLATFORM={0,1} all fip

Enable TBBR by adding the following options to the make command:

MBEDTLS_DIR=<path_to_mbedtls_directory>  \
TRUSTED_BOARD_BOOT=1 \
GENERATE_COT=1 \
ARM_ROTPK_LOCATION=devel_rsa  \
ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem