SUSE Labs Conference 2020 - DMA mapping for the Raspberry Pi 4
Channel: SUSE Labs
Date: 2020-10-06

Conference held using the awesome #bigbluebutton !

After a short overview of Raspberry Pi 4’s hardware design, and commenting on the board’s upstream status, we’ll deep dive into the board’s unique DMA constraints. These, unsupported at the time of its release, forced changes in arm64, DMA, firmware description, and device subsystems. We’ll use these as an excuse to look into how the kernel allocates DMA memory on small IOMMU-less devices, its shortcomings, and possible improvements.