live via QMP, ring sizing decided
include/starkernel/xhci.h: Capability/Operational/Runtime register
layouts, Port Register Set, Interrupter Register Set, Doorbell Array,
16-byte TRB struct -- all from the xHCI 1.2 spec, no existing
reference in this tree to build from (unlike virtio-blk). volatile
fields, no packed attribute, matching virtio_blk.c's documented
riscv64/QEMU-MMIO precedent. Compile-checked clean, sizeof(xhci_trb_t)
verified == 16.
QEMU qemu-xhci's PCI vendor:device ID (0x1B36:0x000D) confirmed live
via QMP query-pci against a real running instance -- not assumed from
memory, matches the Milestone 1 QMP infrastructure just built.
Ring sizing decided: fixed 256-TRB (one page) Command Ring and Event
Ring, single interrupter -- documented rationale in the header.
Bonus finding: src/starkernel/pci/pci.c already has more reusable
infrastructure than Milestone 2b assumed (pci_find_first is ID-based
lookup already existing; pci_bar/pci_map_bar/pci_enable are already
generic) -- 2b is smaller than originally scoped, noted in the punch
list.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
