Brussels / 4 & 5 February 2023


U-Boot as PSCI provider on ARM64

OS kernel on embedded ARM64 systems requires PSCI interface to bring CPU cores up/down, suspend/resume/reset/power off. U-Boot bootloader provides a PSCI interface and this talk explains it.

The talk consists of five parts -- how the PSCI interface works, where and how OS kernel calls it, how and in which hooks on the bootloader side do those calls land, and how those hooks in U-Boot provide functionality required by OS. Last part is an example of U-Boot configured to provide PSCI interface on contemporary SoC .

The benefit of using the U-Boot PSCI interface over other PSCI interface providers is twofold. First, it allows for utilizing the full potential of U-Boot, and especially the SPL preloader, which can then boot OS kernel directly and quickly. Second, removing one software component from the boot stack reduces the Software BoM.


Photo of Marek Vasut Marek Vasut