Imagination GPU Cleared For RISC-V CPU Compatibility, Licensed To Chip Designers

It seems we're a step closer to system-on-chips containing a mix of RISC-V CPU cores and a mainstream GPU powering Linux devices and the like.

Imagination Technologies' BXE-2-32 entry-to-mid-level GPU has been tested and validated to work with RISC-V-compatible CPU cores – and licensed to several companies building RISC-V chips, including RIOS Lab, SiFive, and Yadro, the biz told The Register.

That means we could soon see devices featuring system-on-chips that bring together RISC-V CPU cores and Imagination's graphics-rendering tech.

RISC-V system-on-chips using the BXE GPU could be used for gaming, though right now it's more likely they'll be used in applications ranging from augmented and virtual reality to in-vehicle entertainment systems and wearables, Jim Wallace, senior director of business development at Imagination, told us. Imagination’s GPUs will work with any RISC-V ISA compliant CPU core, he confirmed.

While it's already possible to use, say, an AMD Radeon GPU with PCIe-capable RISC-V systems, such as SiFive's HiFive Unleashed board, using open-source drivers, that's more of a desktop setup.

Imagination's announcement, on the other hand, heralds its early lead in bringing GPUs to RISC-V SoCs, allowing devices of all shapes and sizes to render accelerated graphics using the tech combination.

RISC-V is an up-and-coming alternative to x86 and Arm. RISC-V International sets the open-source specification, which can be used royalty free to implement CPU cores in microprocessors and system-on-chips. Imagination's compliant GPU fills a big gap in the RISC-V world, bringing it closer to offering a truly well-rounded architecture that can take market-dominating rivals. Arm, don't forget, licenses not just CPU cores to chip designers but also GPU engines.

So far, development of RISC-V-friendly graphics processors has been a fragmented effort, though RISC-V International this year is establishing a formal group to develop GPUs, with a focus on shading and artificial intelligence applications.

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Imagination's graphics engines are used in Arm-based mobile chips from the likes of Mediatek. Apple tapped up Imagination's PowerVR architecture for its smartphones, tablets, and parts of its Macs. Imagination is evaluating the compatibility of its GPUs with DirectX, which drives Windows gaming. The BXE is compatible with the Vulkan 1.2, OpenGL ES 3.x/2.0/1.1, OpenCL 3.0, and Android NN HAL APIs, and is primarily aimed at Linux and Android devices.

Imagination has designed its own RISC-V CPU core called Catapult. The IMG BXE-2-32 GPU was validated by Andes Technology using its AX45 64-bit RISC-V CPU on an FPGA, which ran graphics workloads and benchmarks on Linux.

The BXE-series GPUs were launched in late 2020 for applications including entry-level gaming. The chips support 720p to 8K video playback. The FPGA environment included networking, memory, and other peripherals. ®