Split Boot—True Network-Based Booting on Heterogeneous MPSoCs

In the context of the high-luminosity (HL) upgrade of the large hadron collider (LHC), many custom ATCA electronic boards are being designed containing heterogeneous system-on-chip (SoC) devices, more specifically the Xilinx Zynq UltraScale+ (ZUS+) family. While the application varies greatly, these devices are regularly used for performing board management tasks, making them a fundamental element in the correct operation of the board. A large number of hundreds of SoC devices create significant challenges in their firmware deployment, maintenance, and accessibility. Even though U-Boot on ZUS+ devices supports network boot through the preboot execution environment (PXE), the standard ZUS+ boot process contains application-specific information at earlier boot steps, particularly within the first-stage bootloader (FSBL). This prevents the initialization of several devices from a universal image. Inspired by the PXE boot process on desktop PCs, this article describes split boot, a novel boot method tailored to the specific needs of the ZUS+. All application-specific configuration is moved to a network storage device and automatically fetched during the boot process. We considered the entire process, from firmware and software development to binary distribution in a large-scale system. The developed method nicely integrates with the standard Xilinx development toolset workflow.