Livt.Usb

src/host/ControlTransfer.lvt

namespace Livt.Usb.Host

using Livt.Usb

/**
 * Scheduled standard/class request helper borrowing a single-owner controller.
 * Completion remains retained for the caller to inspect and release. No class policy.
 */
component ControlTransfer
{
	// Borrowed transfer slot; caller serializes all uses with other transfers.
	controller: IHostController

	/**
	 * The controller outlives this helper and shares its clock/reset context.
	 */
	new(controller: IHostController)
	{
		this.controller = controller
	}

	/**
	 * Stages an eight-byte request and waits at most 500 frames for its completion.
	 * Supports IN data or no-data requests; OUT payload uses IHostController directly.
	 */
	public fn Run(address: int, packetSize: int, requestType: byte, request: byte,
		value: int, index: int, length: int) bool
	{
		if (controller.GetState() != TransferState.Idle) { return false }

		controller.TryClearStaging()

		for (var position: byte = 0; position < 8; position++) {
			var valueByte: byte

			match position
			{
				0 =>
				{
					valueByte = requestType
				}
				1 =>
				{
					valueByte = request
				}
				2 =>
				{
					valueByte = (value & 255) as byte
				}
				3 =>
				{
					valueByte = ((value >> 8) & 255) as byte
				}
				4 =>
				{
					valueByte = (index & 255) as byte
				}
				5 =>
				{
					valueByte = ((index >> 8) & 255) as byte
				}
				6 =>
				{
					valueByte = (length & 255) as byte
				}
				_ =>
				{
					valueByte = ((length >> 8) & 255) as byte
				}
			}

			if (!controller.TryStageSetup(valueByte)) { return false }
		}

		var direction = TransferDirection.HostToDevice

		if (length != 0) { direction = TransferDirection.DeviceToHost }

		if (controller.TrySubmit(address, 0, TransferKind.Control, direction, packetSize, length, 500, 0) != SubmissionResult.Accepted) { return false }

		while (controller.GetState() == TransferState.Active) {}

		return controller.GetResult() == TransferResult.Success
	}
}