Robert Allan JamesandClaude Sonnet 5
8251aebcf8
Punch list §25 item 4.3.5c complete. Amended from a nonexistent MMIO transport to PCI (matching the board's actual virtio-blk-pci precedent). New virtio-input driver: eventq with pre-posted buffers, PLIC source computed at runtime from PCI slot/pin (derived live from this host's QEMU riscv64 DTB), mandatory ISR-status read, PCI interrupt-disable-bit check. New VKBD-EVENT/VKBD-DEBUG FORTH words. Verified with a real QEMU sendkey keypress: exact KEY_A/press match, two real interrupts serviced, zero exceptions. Three-arch acceptance boot clean. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
68 lines
2.8 KiB
C
68 lines
2.8 KiB
C
/*
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* virtio_input.h — Virtio 1.0 input device driver for StarKernel (item 4.3.5c)
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*
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* riscv64-only today (PCI transport, PLIC interrupt routing). aarch64's
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* 4.3.5e reuses this device identity/event shape over the same PCI
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* transport with GIC routing instead; riscv64/aarch64-specific pieces stay
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* in their own arch trees, not here.
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*
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* Interrupt-driven end to end: the driver pre-posts empty event buffers
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* into the eventq and the device fills+posts them asynchronously, signalled
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* by the PLIC (via 4.3.5b's claim/complete substrate) — no polling.
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*/
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#ifndef STARKERNEL_VIRTIO_INPUT_H
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#define STARKERNEL_VIRTIO_INPUT_H
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#include <stdint.h>
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/* virtio PCI vendor (same device family as virtio-blk) */
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#define VIRTIO_INPUT_PCI_VENDOR_ID 0x1AF4u
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/* Modern-ID formula 0x1040 + VIRTIO_ID_INPUT, VIRTIO_ID_INPUT = 18, per
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* this build host's /usr/include/linux/virtio_ids.h. No legacy/transitional
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* ID exists for virtio-input (postdates the legacy 0.9.5 spec). */
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#define VIRTIO_INPUT_PCI_DEVICE_ID 0x1052u
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/* struct virtio_input_event, per /usr/include/linux/virtio_input.h (BSD
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* licensed, same wire format this driver decodes). */
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typedef struct {
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uint16_t type;
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uint16_t code;
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uint32_t value;
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} VirtioInputEvent;
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/* EV_KEY, per /usr/include/linux/input-event-codes.h */
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#define VIRTIO_INPUT_EV_KEY 0x01u
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/*
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* virtio_input_find_keyboard — locate a virtio-keyboard-pci device on the
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* PCI bus, initialise the driver, compute and
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* enable its PLIC interrupt source (item
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* 4.3.5c's own derivation, FABRIC.md §27.5.2),
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* and pre-post the eventq's receive buffers.
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*
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* Returns 0 on success.
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* Returns -1 if no virtio-keyboard-pci device was found on the PCI bus.
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* Returns -2 on driver initialisation failure (bad BAR, queue setup, etc.).
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*/
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int virtio_input_find_keyboard(void);
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/*
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* virtio_input_isr — called from riscv64_interrupt_handler() when the PLIC
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* claim matches this driver's computed source. Reads the
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* ISR-status capability (mandatory — the routed source
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* is level-triggered; skipping this leaves it latched),
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* drains the used ring, pushes decoded EV_KEY events into
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* the diagnostic ring buffer (keyboard_words.c), and
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* re-posts drained buffers to the eventq's avail ring.
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*/
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void virtio_input_isr(void);
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/*
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* virtio_input_pop_event — diagnostic-ring consumer for keyboard_words.c's
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* VKBD-EVENT, same shape as i8042_pop_scancode().
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* Returns 1 and fills *code and *value if an event was available, 0 otherwise.
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*/
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int virtio_input_pop_event(uint16_t *code, uint32_t *value);
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#endif /* STARKERNEL_VIRTIO_INPUT_H */ |