driver.bus.usb.types¶

USB constants, descriptor structures, transfer types, and utility functions.

Overview¶

This unit defines all shared types and constants used throughout the USB subsystem. It covers USB standard descriptor layouts, transfer abstractions, host controller driver vtables, and utility helpers for working with endpoints and setup packets. All USB subsystem units depend on this unit.

Dependencies¶

core.memory

Constants¶

Descriptor Types¶

USB_DESC_DEVICE ($01), USB_DESC_CONFIG ($02), USB_DESC_STRING ($03), USB_DESC_INTERFACE ($04), USB_DESC_ENDPOINT ($05), USB_DESC_HUB ($29).

Request Codes¶

USB_REQ_GET_STATUS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE, USB_REQ_SET_ADDRESS, USB_REQ_GET_DESCRIPTOR, USB_REQ_SET_DESCRIPTOR, USB_REQ_GET_CONFIGURATION, USB_REQ_SET_CONFIGURATION, USB_REQ_GET_INTERFACE, USB_REQ_SET_INTERFACE.

Request Type Bits¶

USB_REQTYPE_DIR_OUT ($00), USB_REQTYPE_DIR_IN ($80), USB_REQTYPE_TYPE_STANDARD ($00), USB_REQTYPE_TYPE_CLASS ($20), USB_REQTYPE_RECIPIENT_DEVICE ($00), USB_REQTYPE_RECIPIENT_INTERFACE ($01), USB_REQTYPE_RECIPIENT_ENDPOINT ($02).

Endpoint Direction and Type Masks¶

USB_EP_DIR_IN ($80), USB_EP_DIR_OUT ($00), USB_EP_ATTR_CONTROL ($00), USB_EP_ATTR_ISOCHRONOUS ($01), USB_EP_ATTR_BULK ($02), USB_EP_ATTR_INTERRUPT ($03).

Speed Values¶

USB_SPEED_LOW, USB_SPEED_FULL, USB_SPEED_HIGH, USB_SPEED_SUPER.

Class Codes¶

USB_CLASS_HID ($03), USB_CLASS_HUB ($09), USB_CLASS_MASS_STORAGE ($08), USB_CLASS_CDC ($0A).

HC Type IDs¶

HC_TYPE_UHCI, HC_TYPE_OHCI, HC_TYPE_EHCI, HC_TYPE_XHCI.

Types¶

TUSBDeviceDescriptor¶

Standard USB device descriptor (18 bytes). Fields: bLength, bDescriptorType, bcdUSB, bDeviceClass, bDeviceSubClass, bDeviceProtocol, bMaxPacketSize0, idVendor, idProduct, bcdDevice, iManufacturer, iProduct, iSerialNumber, bNumConfigurations.

TUSBConfigDescriptor¶

Standard USB configuration descriptor. Fields: bLength, bDescriptorType, wTotalLength, bNumInterfaces, bConfigurationValue, iConfiguration, bmAttributes, bMaxPower.

TUSBInterfaceDescriptor¶

Standard USB interface descriptor. Fields: bLength, bDescriptorType, bInterfaceNumber, bAlternateSetting, bNumEndpoints, bInterfaceClass, bInterfaceSubClass, bInterfaceProtocol, iInterface.

TUSBEndpointDescriptor¶

Standard USB endpoint descriptor. Fields: bLength, bDescriptorType, bEndpointAddress, bmAttributes, wMaxPacketSize, bInterval.

TUSBHubDescriptor¶

USB hub class descriptor. Fields: bDescLength, bDescriptorType, bNbrPorts, wHubCharacteristics, bPwrOn2PwrGood, bHubContrCurrent, DeviceRemovable.

TUSBSetupPacket¶

8-byte setup packet for control transfers. Fields: bmRequestType, bRequest, wValue, wIndex, wLength.

TUSBTransferStatus¶

Enumeration of possible transfer outcomes: tsPending, tsSuccess, tsError, tsStall, tsTimeout, tsCancelled.

TUSBDirection¶

udIn, udOut.

TUSBPipeType¶

uptControl, uptIsochronous, uptBulk, uptInterrupt.

TUSBEndpoint¶

Parsed endpoint descriptor with fields: Address, Direction, PipeType, MaxPacketSize, Interval.

TUSBTransfer¶

Active transfer record. Fields: Device, Endpoint, Data, Length, Status, HC_Private (host controller internal use).

TUSBDevice¶

Represents an enumerated USB device. Fields: Address, Speed, HC (host controller pointer), DeviceDescriptor, ConfigDescriptor (raw buffer), ConfigLength, MaxPacketSize0.

TUSBHCDriver¶

Host controller vtable record. Function pointer fields:

Field	Signature	Description
`HC_Type`	`uint32`	HC type identifier constant
`Init`	`function: boolean`	Hardware initialisation
`ScanPorts`	`procedure`	Detect connected devices
`Poll`	`procedure`	Process pending transfers
`ControlTransfer`	`function(...)`	Execute a control transfer
`InterruptTransfer`	`function(...)`	Queue an interrupt transfer
`BulkTransfer`	`function(...)`	Queue a bulk transfer
`CancelTransfer`	`procedure(...)`	Cancel a pending transfer

Functions and Procedures¶

kalloc_aligned / kfree_aligned¶

function kalloc_aligned(size, align: uint32): pointer;
procedure kfree_aligned(ptr: pointer);

Allocates or frees memory with the specified byte alignment. Required by host controller hardware that mandates aligned descriptor tables.

make_setup_packet¶

function make_setup_packet(bmRequestType, bRequest: uint8; wValue, wIndex, wLength: uint16): TUSBSetupPacket;

Constructs a TUSBSetupPacket from individual fields.

usb_ep_number / usb_ep_is_in / usb_ep_transfer_type / usb_ep_pipe_type / usb_ep_direction¶

Helper functions that extract sub-fields from a raw bEndpointAddress or bmAttributes byte.

usb_hc_init_record¶

procedure usb_hc_init_record(hc: PUSBHCDriver);

Zero-initialises a TUSBHCDriver record before the host controller driver fills in its function pointers.

UnitTest¶

procedure UnitTest;

Verifies alignment behaviour of kalloc_aligned and correct construction of setup packets.