Livt.Usb

src/host/HostProfile.lvt

namespace Livt.Usb.Host

using Livt.Usb

/**
 * Stateless validation for the initial direct-attachment low/full-speed profile.
 * Provides bounded geometry and request checks without allocating endpoint tables.
 */
component HostProfile<PROFILE_TRANSFER_BYTES: int = 512>
{
	static assert PROFILE_TRANSFER_BYTES >= 8 && PROFILE_TRANSFER_BYTES <= 65535, "Transfer capacity must be 8..65535 bytes"

	// Initial bounded topology; actual table allocation belongs to enumeration.
	public const DEVICE_CAPACITY: int = 1
	public const INTERFACE_CAPACITY: int = 4
	public const ENDPOINT_CAPACITY: int = 4

	/**
	 * Allows control/interrupt at low/full speed and bulk only at full speed.
	 */
	public fn Supports[](speed: UsbSpeed, kind: TransferKind) bool
	{
		if (speed != UsbSpeed.Low && speed != UsbSpeed.Full) {
			return false
		}

		if (kind == TransferKind.Isochronous) {
			return false
		}

		return kind != TransferKind.Bulk || speed == UsbSpeed.Full
	}

	/**
	 * Checks address/endpoint ranges, transfer bounds and endpoint packet geometry.
	 * Does not establish that an endpoint was enumerated; the controller owns binding.
	 */
	public fn IsValid[](speed: UsbSpeed, address: int, endpoint: int, kind: TransferKind,
		maxPacketSize: int, length: int, timeoutFrames: int, intervalFrames: int) bool
	{
		if (!Supports(speed, kind) || address < 0 || address > 127 || endpoint < 0 || endpoint > 15) {
			return false
		}

		if (length < 0 || length > PROFILE_TRANSFER_BYTES || timeoutFrames < 1 || timeoutFrames > 65535) {
			return false
		}

		if (kind == TransferKind.Control) {
			if (endpoint != 0) {
				return false
			}
		} else {
			if (endpoint == 0 || address == 0) {
				return false
			}
		}

		if (kind == TransferKind.Interrupt) {
			var packetLimit: int = 64

			if (speed == UsbSpeed.Low) {
				packetLimit = 8
			}

			return intervalFrames >= 1 && intervalFrames <= 255
				&& maxPacketSize >= 1 && maxPacketSize <= packetLimit
		}

		if (intervalFrames != 0) {
			return false
		}

		if (speed == UsbSpeed.Low) {
			return maxPacketSize == 8
		}

		return maxPacketSize == 8 || maxPacketSize == 16 || maxPacketSize == 32 || maxPacketSize == 64
	}
}