AM67A Beagleboard.org BeagleY-AI

Introduction:

BeagleBoard.org BeagleY-AI is an easy to use, affordable open source hardware single board computer based on the Texas Instruments AM67A, which features a quad-core 64-bit Arm CPU subsystem, 2 general-purpose digital-signal-processors (DSP) and matrix-multiply-accelerators (MMA), GPU, vision and deep learning accelerators, and multiple Arm Cortex-R5 cores for low-power, low-latency GPIO control.

Further information can be found at:

• Product Page: https://beagley-ai.org/

• Hardware documentation: https://openbeagle.org/beagley-ai/beagley-ai

Boot Flow:

Below is the pictorial representation of boot flow:

• On this platform, ‘TI Foundational Security’ (TIFS) functions as the security enclave master while ‘Device Manager’ (DM), also known as the ‘TISCI server’ in "TI terminology", offers all the essential services. The A53 or R5F (Aux core) sends requests to TIFS/DM to accomplish these services, as illustrated in the diagram above.

Sources:

• Das U-Boot

  source: https://source.denx.de/u-boot/u-boot.git

  branch: master

• Trusted Firmware-A (TF-A)

  source: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/

  branch: master

• Open Portable Trusted Execution Environment (OP-TEE)

  source: https://github.com/OP-TEE/optee_os.git

  branch: master

• TI Firmware (TIFS, DM, SYSFW)

  source: https://github.com/TexasInstruments/ti-linux-firmware

  branch: ti-linux-firmware

• TIFS - TI Foundational Security Firmware - Consists of purely firmware meant to run on the security enclave.

• DM - Device Management firmware also called TI System Control Interface server (TISCI Server) - This component purely plays the role of managing device resources such as power, clock, interrupts, dma etc. This firmware runs on a dedicated or multi-use microcontroller outside the security enclave.

• TIFS Stub - The TIFS stub is a small piece of binary designed to help restore the required security context and resume the TIFS firmware when the system resumes from low-power modes such as suspend-to-RAM/Deep Sleep. This stub uses the same encryption and customer key signing model as TIFS and is loaded into the ATCM (Tightly Coupled Memory ‘A’ of the DM R5) during DM startup. Due to the independent certificate signing process, the stub is maintained separately from DM.

Build procedure:

0. Setup the environment variables:

Set the variables corresponding to this platform:

exportCC32=arm-linux-gnueabihf-
exportCC64=aarch64-linux-gnu-
exportLNX_FW_PATH=path/to/ti-linux-firmware
exportTFA_PATH=path/to/trusted-firmware-a
exportOPTEE_PATH=path/to/optee_os

exportUBOOT_CFG_CORTEXR=am67a_beagley_ai_r5_defconfig
exportUBOOT_CFG_CORTEXA=am67a_beagley_ai_a53_defconfig
exportTFA_BOARD=lite
# we dont use any extra TFA parameters
unsetTFA_EXTRA_ARGS
exportOPTEE_PLATFORM=k3-am62x

1. Trusted Firmware-A:

# inside trusted-firmware-a source
makeCROSS_COMPILE=$CC64ARCH=aarch64PLAT=k3SPD=opteed$TFA_EXTRA_ARGS\
TARGET_BOARD=$TFA_BOARD

2. OP-TEE:

# inside optee_os source
makeCROSS_COMPILE=$CC32CROSS_COMPILE64=$CC64CFG_ARM64_core=y$OPTEE_EXTRA_ARGS\
PLATFORM=$OPTEE_PLATFORM

3. U-Boot:

• 3.1 R5:

# inside u-boot source
make$UBOOT_CFG_CORTEXR
makeCROSS_COMPILE=$CC32BINMAN_INDIRS=$LNX_FW_PATH

• 3.2 A53:

# inside u-boot source
make$UBOOT_CFG_CORTEXA
makeCROSS_COMPILE=$CC64BINMAN_INDIRS=$LNX_FW_PATH\
BL31=$TFA_PATH/build/k3/$TFA_BOARD/release/bl31.bin\
TEE=$OPTEE_PATH/out/arm-plat-k3/core/tee-raw.bin

Target Images

Copy these images to an SD card and boot:

• tiboot3-j722s-hs-fs-evm.bin from Cortex-R5 build as tiboot3.bin.

• tispl.bin and u-boot.img from Cortex-A build.

Image formats

• tiboot3.bin

• tispl.bin

Additional hardware for U-Boot development

• Serial Console is critical for U-Boot development on BeagleY-AI. See BeagleY-AI serial console documentation.

• The only onboard storage option is uSD.

• (optionally) JTAG is useful when working with very early stages of boot.

Flash to uSD card or how to deal with "bricked" Board

The only storage option on the platform is uSD card. However, if you choose to hand format your own bootable uSD card, be aware that it can be difficult. The following information may be helpful, but remember that it is only sometimes reliable, and partition options can cause issues. These can potentially help:

• https://git.ti.com/cgit/arago-project/tisdk-setup-scripts/tree/create-sdcard.sh

• https://elinux.org/Beagleboard:Expanding_File_System_Partition_On_A_microSD

• Or manually as follows (may not take into distro needs such as EFI or swap):

# Create image with partition table
parted--script<SDCARDDEVICE>\
mklabelmsdos\
mkpartprimaryfat164MiB20MiB\
mkpartprimaryext420MiB100%\
set1booton\
set1bls_bootoff\
set1lbaon
# Create boot partition
mkfs.vfat<SDCARDDEVICE>1
# Create root partition
mkfs.ext4<SDCARDDEVICE>2

The simplest option is to start with a standard distribution image like those in BeagleBoard.org Distros Page and download a disk image for BeagleY-AI. Pick a 16GB+ uSD card to be on the safer side.

With an SD/MMC Card reader and Balena Etcher, having a functional setup in minutes is a trivial matter, and it works on almost all Host Operating Systems. Yes Windows users, Windows Subsystem for Linux(WSL) based development with U-Boot and update uSD card is practical.

Updating U-Boot is a matter of copying the tiboot3.bin, tispl.bin and u-boot.img to the "BOOT" partition of the uSD card. Remember to sync and unmount (or Eject - depending on the Operating System) the uSD card prior to physically removing from SD card reader.

LED patterns during boot

A53 SPL DDR Memory Layout

This provides an overview memory usage in A53 SPL stage.

Debugging U-Boot

See Common Debugging environment - OpenOCD: for detailed setup and debugging information.

Tag-Connect: Tag-Connect pads on the boards which require special cable. Please check the documentation to identify if "legged" or "no-leg" version of the cable is appropriate for the board.

To debug on these boards, you will need:

• TUMPA or equivalent dongles supported by OpenOCD.

• Tag-Connect cable appropriate to the board such as TC2050-IDC-NL

• In case of no-leg, version, a retaining clip

• Tag-Connect to ARM20 adapter

• External JTAG adapter/interface: In other cases, where an adapter/dongle is used, a simple cfg file can be created to integrate the SoC and adapter information. See supported TI K3 SoCs to decide if the SoC is supported or not.

openocd-fopenocd_connect.cfg

For example, with BeagleY-AI (J722S/AM67A platform), the openocd_connect.cfg:

# TUMPA example:
# http://www.tiaowiki.com/w/TIAO_USB_Multi_Protocol_Adapter_User's_Manual
source[findinterface/ftdi/tumpa.cfg]
transportselectjtag
# default JTAG configuration has only SRST and no TRST
reset_configsrst_onlysrst_push_pull
# delay after SRST goes inactive
adaptersrstdelay20
if{![infoexistsSOC]}{
# Set the SoC of interest
setSOCj722s
}
source[findtarget/ti_k3.cfg]
ftditdo_sample_edgefalling
# Speeds for FT2232H are in multiples of 2, and 32MHz is tops
# max speed we seem to achieve is ~20MHz.. so we pick 16MHz
adapterspeed16000