Online / 6 & 7 February 2021


The LibreSOC Project

a hybrid 3D CPU / VPU / GPU based on OpenPOWER

The LibreSOC Project is a hybrid 3D CPU, GPU and VPU, designed for use in mass-volume products such as smartphones netbooks tablets and Industrial SBC IoT. As such, user trust and reduced product development costs are both equally important. Both these goal are achieved by providing full source right to the bedrock (Hardware HDL, bootloader, drivers, everything) and deploying strict transparent "Libre" development criteria. The project has EUR 350,000 funding from NLnet under their PET Programme and is actively seeking developers.

Analysis of SoCs (system-on-a-chip) used for embedded, mobile and IoT shows a decade-long disturbing persistent trend that is almost 100% without exception across hundreds of integrated processors: not a single recent SoC with modern performance in the past 10 years can be used 100% effectively without at least one closed source driver. The choices for developers and end-users alike is very stark: go without the GPU, or without the VPU, or without some key critical functionality that would penalise performance or business effectiveness entirely, or compromise on integrity and end-user trust, and reduce product reliability by delivering closed source binary-only drivers.

Even the highly-regarded Freescale/NXP iMX.6 which uses Etnaviv for the GPU, and has a 19-year Long-Term Supply committment, is still burdened by closed source 3rd party binary-only drivers for the VPU. Huge multi-man-year efforts consuming precious FOSS engineer resources that could be productively deployed elsewhere are wasted on reverse-engineering these closed SoCs.

The kicker: unlike a Desktop system where swapping out the Graphics Card is a 15 minute job, you cannot replace the VPU or GPU or crypto-block on an integrated System-on-a-Chip, and you certainly cannot disable the boot-level DRM that prevents booting anything other than pre-approved signed versions of u-boot (Otherwise fantastic Windows 10 ARM laptop products using the Tegra processor quickly became landfill due to the BIOS-level DRM locking that chained right through to applications. applications that could only be downloaded once a Microsoft online account had been registered)

This situation is one that is not deliberate: it's a product of how SoCs are put together. It is simply easier for Fabless Semi Companies to license off-the-shelf solutions (GPU hard macro, VPU hard macro) with their associated closed source secretive drivers than it is to tackle what is effectively, to their perspective, a hindrance to sales and profits: issues faced by end-users who know nothing about source code or the close relationship that source code has to "Right to Repair" and security vulnerabilities.

Unbelievably, then, after more than 10 years of waiting for even just one SoC manufacturer to come out with an SoC that has full source code for its GPU, VPU, bootloader and all other integrated HDL, the solution is to design and bring to market an SoC that does exactly that, developing integrated 3D GPU and VPU capability into the same and providing a 100% committment to provide full source, right to the bedrock: HDL, bootloader, drivers, OS: everything.

This huge project requires concerted community effort and coordination with many stakeholders. Significant care is taken to appraise the OpenPOWER Foundation of the ongoing efforts and enhancements being developed on top of OpenPOWER, with a view to proposing the 3D and Video instruction enhancements to the OpenPOWER Foundation for review.


Luke Kenneth Casson Leighton