driver.hid.usb.mouse¶

USB HID boot-protocol mouse driver.

Overview¶

This unit implements a USB HID mouse class driver. It targets the HID boot protocol (subclass $01, protocol $02), which uses fixed 3-byte or 4-byte input reports. After locating the interrupt IN endpoint during load, it submits an initial transfer and relies on poll_mice being called each frame to process completed reports and dispatch events through driver.hid.mouse.

Dependencies¶

driver.bus.usb.core
driver.bus.usb.types
driver.mgr
driver.hid.mouse
driver.hid.ps2.mouse
syslog

Types¶

TUSBMouseData¶

Per-device state record:

Field	Type	Description
`device`	`PUSBDevice`	Pointer to the enumerated USB device
`endpoint`	`TUSBEndpoint`	Interrupt IN endpoint descriptor
`report`	`array[0..3] of uint8`	4-byte HID report buffer
`x`, `y`	`sint32`	Accumulated cursor position
`lmb`, `rmb`	`boolean`	Previous left/right button states
`transfer`	`PUSBTransfer`	Handle to the pending interrupt transfer
`active`	`boolean`	Whether this mouse slot is in use
`fail_count`	`uint8`	Consecutive failure counter

Functions and Procedures¶

init¶

procedure init;

Registers the USB mouse class driver with driver.mgr for USB devices with class $03 (HID), subclass $01 (Boot), protocol $02 (Mouse).

load¶

function load(ptr: pointer): boolean;

Driver load callback. Sends SET_PROTOCOL(Boot) and SET_IDLE(0), locates the interrupt IN endpoint, allocates a TUSBMouseData slot, submits the first interrupt transfer, and disables the PS/2 mouse driver.

poll_mice¶

procedure poll_mice;

Called each kernel frame. On tsSuccess, calls process_report then resubmits the transfer. On error, increments fail_count and deactivates after 3 failures.

process_report (internal)¶

Extracts X delta (mouse_delta_x), Y delta (mouse_delta_y), scroll (mouse_scroll), and button bits (mouse_buttons) from the report buffer. Detects button transitions (press, release, click) and fires the appropriate driver.hid.mouse events. Updates cursor position via driver.hid.mouse.setMousePos.

mouse_delta_x / mouse_delta_y / mouse_scroll¶

Helper functions that sign-extend the relevant report byte to a signed 8-bit value.

mouse_buttons¶

Returns the button state bitmask from report byte 0.

UnitTest¶

procedure UnitTest;

Verifies delta extraction, scroll sign extension, and button bitmask parsing.

Notes¶

The boot protocol report layout is: byte 0 = button bitmask (bits 0=left, 1=right, 2=middle), byte 1 = X delta (signed), byte 2 = Y delta (signed), byte 3 = scroll (signed, optional).
The driver disables the PS/2 mouse on successful load to prevent duplicate pointer events.