x86_q35: add keyboard driver over i8042 controller #4595
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2 tasks
alexandruradovici
requested changes
Sep 11, 2025
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step1: PS/2 controller self-test (clock & IRQ still disabled) step2: enable keyboard clock (IRQ 1 still masked) step3: full PS/2 driver – self-test, clock on, IRQ1 unmasked, single-byte buffering step4: drain-loop IRQ handler; full ring-buffer active step5: add send_with_ack() with RESEND retry; enable keyboard scanning (0xF4) step7: implemented some unit tests to debug buffers fix: readded comments from previous controller, moved ps2.init() to enable debug macro feature: added IRQ1 self-test when init.
workflow: rebased with upstream
…for init, reworked ISR to handle drop parity/timeout => make/break logs + prefixes
…lf to keep ISR tny, minor polish
…spin number, removed helper functions
…vide API for keyevent/keyboardClient
…, optional AsciiClient for future capsule
… keyboard works, removed debug messages
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bradjc
reviewed
Sep 26, 2025
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Is there a PR that uses this in main.rs? It would be good to have an example of using the keyboard, particularly so we can try it out. |
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Yes! A PR is in the works, the TextScreen capsule PR includes a minimal Here's how it looks : left is the PC on VGA, right is Serial for debugging |
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Pull Request Overview
This adds a PS/2 keyboard driver for x86_q35, layered over the i8042 controller.
Set-2 decoder: handles E0 (extended), F0 (break), and swallows the E1 Pause sequence.
Minimal event model (KeyEvent): make/break + extended bit.
Optional ASCII path (US layout): press-only, non-extended, with Shift/Caps handling.
Small command engine (non-alloc FIFO) for device commands with ACK (0xFA) / RESEND (0xFE) retry logic.
Defensive indexing via bounds-checked access in the command queue (no panics).
Dependencies
Testing Strategy
Built and ran under QEMU; typed sequences to verify:
MAKE/BREAK decoding (including E0-extended keys).
ASCII emission path (letters, digits, common punctuation; Shift/Caps).
Non-keystroke device responses (0xFA/0xFE/0xAA) are ignored unless a command is in flight.
Command engine present and compiled; it will be exercised when we move device init from the controller to the keyboard/capsule.
TODO or Help Wanted
Move the keyboard init sequence (F5 -> FF -> F0 02 -> F4) from the controller into the keyboard using the command engine.
Hook a capsule (client) to consume KeyEvent / ASCII (e.g., process console over VGA).
Documentation Updated
/docs, or no updates are required.Formatting
make prepush.