Runs in: Kernel-only — hardware/HAL access runs in supervisor context and is never executed from a user thread. User-space audio code reaches driver functionality only through SOF syscalls (e.g. the sof_dma_* and dai_get_device calls). See User/kernel split.

This directory contains low-level device drivers and hardware abstraction. Because it touches MMIO, interrupts and other privileged resources, nothing here is mapped into a user memory domain. If user-space code needs a driver operation, expose it through a validated syscall in the boundary tier rather than linking this code into a user thread.