x86_q35: add ps/2 controller to connect mouse and keyboard peripherals for VGA #4594
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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
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chips/x86_q35/src/ps2.rs
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| /// Client hook (future: keyboard capsule) | ||
| pub trait Ps2Client { | ||
| fn receive_scancode(&self, code: u8); | ||
| } |
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We do have a keyboard HIL now.
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I removed the old P2Client and added the keyboard HIL. Will take a look to see how should I implement it in the keyboard driver.
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Edit regarding my previous message (prepare for a loong message :D )
We split the PS/2 stack into two layers:
Controller (transport): ps2.rs
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Owns the i8042 hardware: port I/O, status polling, bring-up (self-test, config, Set-2, enable IRQ1).
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IRQ top-half enqueues raw bytes; deferred call (bottom-half) drains a ring buffer and forwards bytes to a small, local hook:
Keyboard (device): keyboard.rs
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Implements the new
kernel::hil::keyboard::Keyboard<'a>and calls the HIL client via:c.keys_pressed(&[(linux_keycode, pressed)], Ok(())); -
Implements Ps2Client so the controller can feed it raw bytes.
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Provides a Set-2 decoder (E0/F0/E1) and emits MAKE/BREAK logs after prefix resolution.
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Maps Set-2 - Linux keycodes (initial coverage: letters, digits, common modifiers, arrows).
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Contains a small command engine (ACK/RESEND FIFO) for device commands (to move full init here later and to send commands).
(i wrote this in x86_q35: add keyboard driver over i8042 controller #4595)
Now the big question :
Why keep Ps2Client if we have a keyboard HIL now ?
Ps2Client is not another HIL; it’s a tiny internal hook for the controller to deliver raw scancodes to some consumer (the keyboard device here, but could be a mouse/AUX later). The actual HIL interface is implemented in keyboard.rs (emitting Linux keycodes + press/release), which matches the new kernel/src/hil/keyboard.rs. We removed the old ASCII path and byte emission. We now rely solely on the HIL interface for key events.
This separation keeps responsibilities clean:
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Controller = reusable i8042 transport (also future-proof for AUX/mouse).
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Keyboard = device semantics (decode, mapping, HIL emission).
| // PS/2 inside the component | ||
| let ps2 = | ||
| unsafe { static_init!(crate::ps2::Ps2Controller, crate::ps2::Ps2Controller::new()) }; | ||
| kernel::deferred_call::DeferredCallClient::register(ps2); |
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Now is not that time, but at some point we need to stop adding new static_init here, which shouldn't have ever been here.
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Once we have #4595 ready and the PR which uses this stack we can start merging these. |
Pull Request Overview
This pull request adds an i8042 PS/2 controller for the x86_q35 platform and wires it into the board/chip (all was done according to https://wiki.osdev.org/I8042_PS/2_Controller)
Implements controller bring-up (init_early): disable ports, flush OB, self-test, typed config byte updates (translation OFF, clocks/IRQs as needed), keyboard port test/enable, and device init (F5, FF => AA, F0 02, F4).
Interrupt/top-half: reads OB, drops bytes with parity/timeout errors, enqueues scan codes, and schedules a deferred call.
Deferred/bottom-half: drains a ring buffer and currently logs Set-2 MAKE/BREAK lines; also exposes a client hook:
pub trait Ps2Client { fn receive_scancode(&self, code: u8); }pub fn set_client(&self, client: &'static dyn Ps2Client)Observability: adds
Ps2Health { bytes_rx, overruns, parity_err, timeout_err, timeouts, resends }andhealth_snapshot(), with periodic debug logging.Uses
LocalRegisterCopy<u8, CONFIG::Register>for typed, safe CONFIG-byte manipulation.Integrates with PcComponent: registers as a DeferredCallClient, dispatches IRQ1 to the controller, and runs bring-up during finalize.
Testing Strategy
This pull request was tested by running on QEMU
Verified IRQ1 fires, ISR queues bytes, and deferred call drains/logs MAKE/BREAK for key presses.
Observed bytes_rx increasing in health logs; no parity/timeout drops seen during normal typing.
Confirmed no regressions in PIT and serial console paths; kernel boots and services interrupts normally.
TODO or Help Wanted
Documentation Updated
/docs, or no updates are required.Formatting
make prepush.