Module mmio 

Memory-mapped I/O access for userspace driver services (§12, §18).

This is the SDK’s audited hardware-access layer - one of the places outside the kernel where unsafe is permitted. §18.1 names this file alongside dma.rs, the syscall ABI (raw_syscall) and adversarial.rs; this said “one of the two places”, which dma.rs’s own header already contradicted. Driver services use the safe Mmio wrapper and never write unsafe themselves; every volatile access below carries a SAFETY argument, and Mmio is only constructable inside this crate (from a kernel-granted mapping), so its base pointer is always valid by construction.

Structs

Framebuffer

A mapped framebuffer granted to the console service (via crate::ServiceContext::framebuffer), plus the geometry needed to address a pixel in it.

Mmio

A mapped MMIO region granted to a driver (e.g. via crate::ServiceContext::xhci_mmio). Read/write device registers by byte offset. All accesses are volatile - never reordered or elided - and target the uncached device registers directly, with no kernel mediation (§12).