From be868a43185826b02bf6d091019bb779678525bb Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Mon, 17 Aug 2026 14:53:52 +0200
Subject: 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
---
 rsnix/src/tty.rs | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

(limited to 'rsnix/src/tty.rs')

diff --git a/rsnix/src/tty.rs b/rsnix/src/tty.rs
index 7304925..0783521 100644
--- a/rsnix/src/tty.rs
+++ b/rsnix/src/tty.rs
@@ -1,4 +1,8 @@
-//! Line discipline over the PS/2 keyboard — the kernel's tty layer.
+//! Line discipline over the keyboard — the kernel's tty layer.
+//!
+//! Keys come from either the PS/2 controller (IRQ-fed scancode ring) or the
+//! USB HID boot keyboard (polled UHCI driver).  Both are translated to the
+//! same `KeyEvent` space, so the shell is input-source agnostic.
 //!
 //! Two modes, like a real UNIX terminal:
 //! - **canonical** (`read_line`): input is echoed, buffered until Enter,
@@ -34,6 +38,20 @@ pub enum LineInput {
 static mut RAW_QUEUE: [u8; 8] = [0; 8];
 static mut RAW_LEN: usize = 0;
 
+/// Combined blocking key poll: USB HID keyboard first (polled UHCI), then
+/// the PS/2 path (which parks via `hlt` until an IRQ-fed scancode lands).
+fn poll_key() -> KeyEvent {
+    if let Some(ev) = crate::uhci::try_poll_key() {
+        return ev;
+    }
+    ps2::poll_key()
+}
+
+/// Combined non-blocking key poll (USB first, then PS/2).
+fn try_poll_key() -> Option<KeyEvent> {
+    crate::uhci::try_poll_key().or_else(ps2::try_poll_key)
+}
+
 // ---------------------------------------------------------------------------
 // canonical mode
 // ---------------------------------------------------------------------------
@@ -46,7 +64,7 @@ pub fn read_line() -> LineInput {
     crate::vt::sync_scroll();
     let mut buf = strbuf::String::<LINE_BUF_SIZE>::new();
     loop {
-        match ps2::poll_key() {
+        match poll_key() {
             KeyEvent::Enter => {
                 gop::put_char('\n');
                 serial::write_str("\r\n");
@@ -104,7 +122,7 @@ pub fn read_line() -> LineInput {
 /// streaming commands (cat/hexdump) so a long dump can be interrupted.
 pub fn interrupt_pressed() -> bool {
     let mut pressed = false;
-    while let Some(ev) = ps2::try_poll_key() {
+    while let Some(ev) = try_poll_key() {
         if matches!(ev, KeyEvent::Ctrl('c')) {
             pressed = true;
         }
@@ -126,7 +144,7 @@ pub fn read_byte() -> u8 {
         if let Some(b) = pop_raw() {
             return b;
         }
-        let ev = ps2::poll_key();
+        let ev = poll_key();
         enqueue_key(ev);
     }
 }
@@ -136,7 +154,7 @@ pub fn try_read_byte() -> Option<u8> {
     if let Some(b) = pop_raw() {
         return Some(b);
     }
-    match ps2::try_poll_key() {
+    match try_poll_key() {
         Some(ev) => {
             enqueue_key(ev);
             pop_raw()
-- 
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