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use core::marker::PhantomData;
use log::{error, info, trace, warn};
use crate::descriptor::microsoft10;
use crate::device::Descriptors;
use crate::event::UsbEvent;
use crate::setup::{Direction, Feature, Recipient, Request, RequestType, SetupPacket};
use crate::traits::{AsByteSliceIterator, UsbDriver};
// - State --------------------------------------------------------------------
/// Represents the current state of the Control interface.
#[derive(Clone, Copy, Debug)]
pub enum State {
Idle,
Send,
WaitForZlp,
SetAddress(u8),
ReceiveHostData(SetupPacket),
FinishHostData(SetupPacket),
Complete,
Stall,
}
// - Control ------------------------------------------------------------------
/// Implements a USB Control endpoint.
pub struct Control<'a, D, const RX_BUFFER_SIZE: usize> {
endpoint_number: u8,
descriptors: Descriptors<'a>,
next: State,
configuration: Option<u8>,
feature_remote_wakeup: bool,
rx_buffer: [u8; RX_BUFFER_SIZE],
rx_buffer_position: usize,
_marker: PhantomData<&'a D>,
}
impl<'a, D, const RX_BUFFER_SIZE: usize> Control<'a, D, RX_BUFFER_SIZE>
where
D: UsbDriver,
{
/// Returns the last received control data from the host.
#[must_use]
pub fn data(&'a self) -> &'a [u8] {
&self.rx_buffer[..self.rx_buffer_position]
}
fn write_zlp(&self, usb: &D) {
usb.write(self.endpoint_number, [].into_iter());
}
fn read_zlp(&self, usb: &D) -> bool {
usb.read(self.endpoint_number, &mut [0; crate::EP_MAX_PACKET_SIZE]) == 0
}
}
impl<'a, D, const RX_BUFFER_SIZE: usize> Control<'a, D, RX_BUFFER_SIZE>
where
D: UsbDriver,
{
#[must_use]
pub fn new(endpoint_number: u8, descriptors: Descriptors<'a>) -> Self {
Self {
endpoint_number,
descriptors: descriptors.set_total_lengths(), // TODO figure out a better solution
next: State::Idle,
configuration: None,
feature_remote_wakeup: false,
rx_buffer: [0; RX_BUFFER_SIZE],
rx_buffer_position: 0,
_marker: PhantomData,
}
}
/// Dispatches an interrupt event generated by the USB peripheral
/// for handling by the [`Control`] interface.
///
/// Returns the last [`SetupPacket`] received if it could not be
/// handled by the [`Control`] interface. (e.g. if it was a
/// [`RequestType::Class`] or [`RequestType::Vendor`] request)
#[allow(clippy::too_many_lines)] // sometimes you can't have too much of a good thing!
pub fn dispatch_event(&mut self, usb: &D, event: UsbEvent) -> Option<SetupPacket> {
// The Control interface state machine operates on the latest
// receive event and the current state of the interface.
match (event, &self.next.clone()) {
(UsbEvent::BusReset, _state) => {
// reset
self.next = State::Idle;
// self.bus_reset(); - irq handler is doing the reset for us
}
(
UsbEvent::ReceiveSetupPacket(endpoint_number, setup_packet),
State::Idle | State::Stall,
) if endpoint_number == self.endpoint_number => {
if matches!(self.next, State::Stall) {
// clear State::Stall
self.next = State::Idle;
}
let requested_length = setup_packet.length as usize;
match (
setup_packet.direction(),
setup_packet.request_type(),
setup_packet.request(),
) {
// handle microsoft os 1.0 descriptor requests
//
// reg entries are:
//
// Microsoft OS 1.0 String Descriptor: <VID><PID><bcdDevice> => 1d50615b0104
// HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\usbflags\1D50615B0104
// HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbflags\1D50615B0104
//
// Compatible ID Feature Descriptor: VID_<VID>&PID_<PID> => VID_1d50&PID_615b
// HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB\VID_1d50&PID_615b
//
(
Direction::DeviceToHost,
RequestType::Vendor,
Request::ClassOrVendor(microsoft10::VendorRequest::Microsoft),
) => {
let recipient = setup_packet.recipient();
let vendor_index = microsoft10::VendorIndex::from(setup_packet.index);
match (&recipient, &vendor_index, &self.descriptors.microsoft10) {
(
Recipient::Device,
microsoft10::VendorIndex::CompatibleIdFeatureDescriptor,
Some(descriptors),
) => {
self.next = State::Send;
usb.write_requested(
self.endpoint_number,
requested_length,
descriptors
.compat_id_feature_descriptor
.iter()
.copied()
.take(requested_length),
);
}
(
Recipient::Interface,
microsoft10::VendorIndex::ExtendedPropertiesFeatureDescriptor,
Some(descriptors),
) => {
self.next = State::Send;
usb.write_requested(
self.endpoint_number,
requested_length,
descriptors
.extended_properties_feature_descriptor
.as_iter()
.copied()
.take(requested_length),
);
}
_ => {
self.next = State::Stall;
error!(
"Control error. Could not handle Microsoft OS 1.0 Request: '{:?}'.",
setup_packet
);
usb.stall_endpoint_in(self.endpoint_number);
}
}
}
// - standard requests
(Direction::DeviceToHost, RequestType::Standard, Request::GetDescriptor) => {
self.next = State::Send;
return self
.descriptors
.write(usb, self.endpoint_number, setup_packet);
}
(Direction::HostToDevice, RequestType::Standard, Request::SetAddress) => {
let address: u8 = (setup_packet.value & 0x7f) as u8;
self.next = State::SetAddress(address);
self.write_zlp(usb);
}
(Direction::HostToDevice, RequestType::Standard, Request::SetConfiguration) => {
let configuration: u8 = (setup_packet.value & 0xff) as u8;
// check whether this is a valid configuration
// TODO support multiple configurations
if configuration > 1 {
warn!("Control stall - unknown configuration {}", configuration);
self.configuration = None;
self.next = State::Stall;
usb.stall_endpoint_out(self.endpoint_number);
return None;
}
self.configuration = Some(configuration);
self.next = State::Complete;
self.write_zlp(usb);
}
(Direction::DeviceToHost, RequestType::Standard, Request::GetConfiguration) => {
self.next = State::Send;
if let Some(configuration) = self.configuration {
usb.write(self.endpoint_number, [configuration].into_iter());
} else {
usb.write(self.endpoint_number, [0].into_iter());
}
}
(Direction::DeviceToHost, RequestType::Standard, Request::GetStatus) => {
let status: u16 = 0b01; // bit 1:remote-wakeup bit 0:self-powered
let status = status | u16::from(self.feature_remote_wakeup) << 1;
self.next = State::Send;
usb.write(0, status.to_le_bytes().into_iter());
}
(direction, RequestType::Standard, Request::ClearFeature) => {
info!(" TODO Request::ClearFeature {:?}", direction);
let recipient = setup_packet.recipient();
let feature = Feature::from(setup_packet.value);
match (&recipient, &feature) {
(Recipient::Endpoint, Feature::EndpointHalt) => {
let endpoint_address = (setup_packet.index & 0xff) as u8;
let endpoint_number = endpoint_address & 0x7f;
let direction = Direction::from(endpoint_address);
usb.clear_feature_endpoint_halt(endpoint_number, direction);
self.next = State::Complete;
self.write_zlp(usb);
}
(Recipient::Device, Feature::DeviceRemoteWakeup) => {
self.feature_remote_wakeup = false;
self.next = State::Complete;
self.write_zlp(usb);
}
_ => {
warn!(
"SETUP stall: unhandled clear feature {:?}, {:?}",
recipient, feature
);
self.next = State::Stall;
usb.stall_endpoint_in(self.endpoint_number);
}
}
}
(direction, RequestType::Standard, Request::SetFeature) => {
info!(" TODO Request::SetFeature {:?}", direction);
let recipient = setup_packet.recipient();
let feature = Feature::from(setup_packet.value);
self.next = State::Complete;
match (&recipient, &feature) {
(Recipient::Device, Feature::DeviceRemoteWakeup) => {
self.feature_remote_wakeup = true;
self.write_zlp(usb);
}
_ => {
warn!(
"SETUP stall: unhandled set feature {:?}, {:?}",
recipient, feature
);
usb.stall_endpoint_in(self.endpoint_number);
self.next = State::Stall;
}
}
}
// - unsupported requests with host data we need to read
(Direction::HostToDevice, _, _) if setup_packet.length > 0 => {
self.rx_buffer_position = 0;
self.next = State::ReceiveHostData(setup_packet);
usb.ep_out_prime_receive(self.endpoint_number); // prime to receive data from host
}
// - unsupported requests
(direction, request_type, request) => {
trace!(
"Unhandled request direction:{:?} request_type:{:?} request:{:?}",
direction,
request_type,
request
);
self.next = State::Idle;
return Some(setup_packet);
}
}
}
// - handle states ------------------------------------------------
(UsbEvent::SendComplete(endpoint_number), State::Send)
if endpoint_number == self.endpoint_number =>
{
self.next = State::WaitForZlp;
// prime to receive zlp from host
usb.ep_out_prime_receive(self.endpoint_number);
}
(UsbEvent::SendComplete(endpoint_number), State::WaitForZlp)
if endpoint_number == self.endpoint_number =>
{
// it's part of a multi-packet send, we can safely ignore this
}
(UsbEvent::ReceivePacket(endpoint_number), State::WaitForZlp)
if endpoint_number == self.endpoint_number =>
{
self.next = State::Idle;
if !self.read_zlp(usb) {
warn!(
"Control {:?} {:?} expected a ZLP but received data instead.",
event, self.next
);
}
}
(UsbEvent::SendComplete(endpoint_number), &State::SetAddress(address))
if endpoint_number == self.endpoint_number =>
{
self.next = State::Idle;
usb.set_address(address); // set address
}
(UsbEvent::SendComplete(endpoint_number), State::Complete)
if endpoint_number == self.endpoint_number =>
{
self.next = State::Idle;
}
(UsbEvent::ReceivePacket(endpoint_number), &State::ReceiveHostData(setup_packet))
if endpoint_number == self.endpoint_number =>
{
let mut packet_buffer: [u8; crate::EP_MAX_PACKET_SIZE] =
[0; crate::EP_MAX_PACKET_SIZE];
let bytes_read = usb.read(self.endpoint_number, &mut packet_buffer);
// handle early abort
if bytes_read == 0 {
warn!("Control receive early abort");
// we're done
self.next = State::FinishHostData(setup_packet);
self.write_zlp(usb);
return None;
}
// handle buffer overflow
if self.rx_buffer_position + bytes_read > RX_BUFFER_SIZE {
error!("Control receive buffer overflow, truncating.");
// keep reading until the host has no more data to send
self.next = State::ReceiveHostData(setup_packet);
usb.ep_out_prime_receive(self.endpoint_number);
return None;
}
// append packet to rx_buffer
let offset = self.rx_buffer_position;
self.rx_buffer[offset..offset + bytes_read]
.copy_from_slice(&packet_buffer[..bytes_read]);
self.rx_buffer_position += bytes_read;
// are we done yet?
if self.rx_buffer_position >= usize::from(setup_packet.length) {
// we're done
self.next = State::FinishHostData(setup_packet);
self.write_zlp(usb);
} else {
// get ready to receive more data
self.next = State::ReceiveHostData(setup_packet);
// prime to receive next block of data from host
usb.ep_out_prime_receive(self.endpoint_number);
}
}
(UsbEvent::SendComplete(endpoint_number), &State::FinishHostData(setup_packet))
if endpoint_number == self.endpoint_number =>
{
// we've sent our zlp and now we are done
self.next = State::Idle;
// check for length mismatch
if self.rx_buffer_position != usize::from(setup_packet.length) {
warn!(
"Control expected {} bytes of data from the host, but received {} bytes.",
setup_packet.length, self.rx_buffer_position,
);
}
return Some(setup_packet);
}
// we'll get these if someone is writing directly to usb1 outside control
(UsbEvent::ReceivePacket(endpoint_number), State::Idle)
if endpoint_number == self.endpoint_number =>
{
if !self.read_zlp(usb) {
warn!("Control expected a ZLP but received data instead.");
}
}
(UsbEvent::SendComplete(endpoint_number), State::Idle)
if endpoint_number == self.endpoint_number =>
{
// do nothing
}
(event, state) => {
self.next = State::Idle;
error!(
"Control state error. Received event '{:?}' while in state '{:?}'.",
event, state
);
}
}
None
}
}