Makefile & configs for building U-Boot and Linux for TechNexion's PICO-PI-IMX8M

These configuration files are a result of the 2024 ARM Summer School, held in the Faculty of Automatic Control and Computer Science of the POLITEHNICA University of Bucharest and sponsored by Google.

Warning: This Makefile is intended to be run on a Debian-based Linux system. It might wipe unintended disks. Inspect the code for the 9-diskimg and boot-linux stages and make sure you don't have disks matching those modified by the script. Running these stages may require root privileges.

Dependencies

Before running the Makefile, ensure that you have the necessary dependencies installed. The 0-config stage attempts to install them automatically. The packages required are: build-essential, libusb-1.0-0-dev, libbz2-dev, libzstd-dev, pkg-config, cmake, libssl-dev, g++, zlib1g-dev, libtinyxml2-dev, libzip-dev, unzip, bison, flex, device-tree-compiler.

The Makefile uses apt to install these packages, so it is intended for Debian-based systems.

Makefile Stages

The Makefile is separated into stages, each building on the dependencies needed to boot Linux on the board.

• 0-config: Prepares the dependencies required for building the image. It installs necessary packages if they are not already installed.
• 1-atf: Downloads the Trusted Firmware-A (BL31) from NXP's GitHub repository (branch lf_v2.6) and compiles it.
• 2-nxp-fw: Downloads NXP's i.MX Firmware (BL2) version 8.9 from the Buildroot sources. Please note this auto-accepts an EULA while extracting the files.
• 3-uboot: Downloads and compiles a TechNexion-customized variant of U-Boot from their GitHub repository (branch tn-imx_v2023.04_6.1.55_2.2.0-stable).
  • 3-uboot-prepare
  • 3-uboot-compile
• 4-nxp-mkimg: Packages U-Boot and the firmware in a firmware package using NXP's imx-mkimage tool from their repository (branch lf-5.15.32_2.0.0).
• 5-nxp-uuu: Downloads and compiles the Universal Update Utility (UUU) customized by NXP from their repository.
• boot-u: Used for only booting U-Boot.
• 6-linux: Downloads (from Torvalds' Linux repository, branch v6.6), configures, and compiles the Linux kernel.
  • 6-linux-prepare
  • 6-linux-compile
• 7-buildroot: Downloads (from Buildroot repository, version 2024.05.1), configures, and builds a Linux root filesystem using Buildroot.
  • 7-buildroot-prepare
  • 7-buildroot-compile
• 8-fit: Creates the Flattened Image Tree (FIT) image.
• 9-diskimg: Creates the disk image.
• boot-linux: Boots U-Boot and then Linux, entirely without user interaction.

Important Note:

Disk Modification Risk: The 9-diskimg and boot-linux stages involve disk operations that could potentially overwrite your disk data. Before running these stages, ensure that you have disconnected all unnecessary storage devices to prevent data loss.

Usage

To build all stages, run:

make all

You can also build individual stages by specifying the target. For example:

make 1-atf

To clean all generated directories, run:

make clean-all

To list all available targets, run:

make list

Notes

• Root Privileges: Some stages may require root privileges due to operations like installing packages, mounting file systems, and writing to disks.

• Serial Device Configuration: By default, the serial device is set to /dev/ttyUSB0. If your serial device differs, modify the SERIAL_DEVICE variable in the Makefile accordingly.

• User Interaction: The boot-linux target attempts to automate the booting process. It waits for U-Boot to boot, sends commands over the serial connection, and writes the disk image to the device. Monitor the process carefully.

License Agreement

Please be aware that by downloading and extracting NXP's i.MX Firmware in stage 2-nxp-fw, you agree to their EULA, which is auto-accepted during extraction.

Troubleshooting

• Missing Packages: If the automatic installation of packages fails, manually install the required packages listed in the Dependencies section.

• Disk Not Found: If the script cannot find the appropriate disk to write the image, verify your connected devices and adjust the script if necessary.

• Compilation Errors: Ensure that all dependencies are installed and that you're using compatible versions of the tools and compilers.

Contributions

Contributions are welcome. Please inspect the code and ensure safety before running any stages that modify disks.