ARM Trusted Firmware for Raspberry Pi 4

The bl31.bin TF-A binary found in this directory was built from the
official TF-A 2.5 release
through a GitHub build script
that is designed to provide evidence that these binaries match the vanilla TF-A source.

Per the GitHub Actions log,
the SHA-256 sum for the bin can be validated to be as follows:
- bl31.bin: 59c4486a0a257c8d630d8ea39d6a13d038cd50be4fc9a81985bf2c32a7c3fca6

For Raspberry Pi 4 usage, TF-A was built using the command:
make PLAT=rpi4 RPI3_PRELOADED_DTB_BASE=0x1F0000 PRELOADED_BL33_BASE=0x20000 SUPPORT_VFP=1 DEBUG=0 all