USB2/1.1 (EHCI/UHCI) drivers + real-hardware bring-up hardening

- Add polled EHCI (USB2) and UHCI (USB1.1) host-controller drivers with
  HID boot mouse support, wired into cursor polling and the 'usb' shell cmd
- Add USB Legacy ownership handoff (claim_usb_legacy) plus config_write_byte
- Harden boot: verify the PIT/timer ticks before shell entry, EOI stray
  interrupts in the LAPIC to stop interrupt storms, bound PS/2 controller
  waits, and INTx-disable AHCI (polled driver)
- Add boot stage markers, klog screen echo, and QR lock; scheduler
  mark_shell_running; NO_USB stopgap to keep BIOS USB-Legacy input alive
- alloc_pages_above for DMA buffers that must avoid low conventional memory
- Expand DEBUG_NOTES with EHCI/QEMU bring-up findings

1 files changed, 2 insertions, 0 deletions

diff --git a/rsnix/src/lib.rs b/rsnix/src/lib.rs
index bc2553d..f5c3419 100644
--- a/rsnix/src/lib.rs
+++ b/rsnix/src/lib.rs
@@ -17,6 +17,8 @@ pub mod pci;
 pub mod qr;
 pub mod power;
 pub mod ps2;
+pub mod uhci;
+pub mod ehci;
 pub mod usb;
 pub mod rtc;
 pub mod sched;