embassy/embassy-usb/src/lib.rs
Dario Nieuwenhuis 092c2b7dfe usb: builtin handling of interface alternate settings
The stack reads its own descriptors to figure out which endpoints
are used in which alt settings, and enables/disables them as needed.

The ControlHandler has a callback so it can get notified of alternate
setting changes, which is purely informative (it doesn't have to do anything).
2022-04-23 01:11:10 +02:00

566 lines
21 KiB
Rust

#![no_std]
#![feature(generic_associated_types)]
#![feature(type_alias_impl_trait)]
// This mod MUST go first, so that the others see its macros.
pub(crate) mod fmt;
mod builder;
pub mod control;
pub mod descriptor;
mod descriptor_reader;
pub mod driver;
pub mod types;
use embassy::util::{select, Either};
use heapless::Vec;
use crate::descriptor_reader::foreach_endpoint;
use self::control::*;
use self::descriptor::*;
use self::driver::{Bus, Driver, Event};
use self::types::*;
pub use self::builder::Builder;
pub use self::builder::Config;
/// The global state of the USB device.
///
/// In general class traffic is only possible in the `Configured` state.
#[repr(u8)]
#[derive(PartialEq, Eq, Copy, Clone, Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum UsbDeviceState {
/// The USB device is disabled.
Disabled,
/// The USB device has just been enabled or reset.
Default,
/// The USB device has received an address from the host.
Addressed,
/// The USB device has been configured and is fully functional.
Configured,
}
#[derive(PartialEq, Eq, Copy, Clone, Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum RemoteWakeupError {
InvalidState,
Unsupported,
}
impl From<driver::Unsupported> for RemoteWakeupError {
fn from(_: driver::Unsupported) -> Self {
RemoteWakeupError::Unsupported
}
}
/// The bConfiguration value for the not configured state.
pub const CONFIGURATION_NONE: u8 = 0;
/// The bConfiguration value for the single configuration supported by this device.
pub const CONFIGURATION_VALUE: u8 = 1;
pub const MAX_INTERFACE_COUNT: usize = 4;
/// A handler trait for changes in the device state of the [UsbDevice].
pub trait DeviceStateHandler {
/// Called when the USB device has been enabled or disabled.
fn enabled(&self, _enabled: bool) {}
/// Called when the host resets the device.
fn reset(&self) {}
/// Called when the host has set the address of the device to `addr`.
fn addressed(&self, _addr: u8) {}
/// Called when the host has enabled or disabled the configuration of the device.
fn configured(&self, _configured: bool) {}
/// Called when the bus has entered or exited the suspend state.
fn suspended(&self, _suspended: bool) {}
/// Called when remote wakeup feature is enabled or disabled.
fn remote_wakeup_enabled(&self, _enabled: bool) {}
}
struct Interface<'d> {
handler: Option<&'d mut dyn ControlHandler>,
current_alt_setting: u8,
num_alt_settings: u8,
}
pub struct UsbDevice<'d, D: Driver<'d>> {
bus: D::Bus,
handler: Option<&'d dyn DeviceStateHandler>,
control: ControlPipe<D::ControlPipe>,
config: Config<'d>,
device_descriptor: &'d [u8],
config_descriptor: &'d [u8],
bos_descriptor: &'d [u8],
control_buf: &'d mut [u8],
device_state: UsbDeviceState,
suspended: bool,
remote_wakeup_enabled: bool,
self_powered: bool,
pending_address: u8,
interfaces: Vec<Interface<'d>, MAX_INTERFACE_COUNT>,
}
impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
pub(crate) fn build(
mut driver: D,
config: Config<'d>,
handler: Option<&'d dyn DeviceStateHandler>,
device_descriptor: &'d [u8],
config_descriptor: &'d [u8],
bos_descriptor: &'d [u8],
interfaces: Vec<Interface<'d>, MAX_INTERFACE_COUNT>,
control_buf: &'d mut [u8],
) -> UsbDevice<'d, D> {
let control = driver
.alloc_control_pipe(config.max_packet_size_0 as u16)
.expect("failed to alloc control endpoint");
// Enable the USB bus.
// This prevent further allocation by consuming the driver.
let bus = driver.into_bus();
Self {
bus,
config,
handler,
control: ControlPipe::new(control),
device_descriptor,
config_descriptor,
bos_descriptor,
control_buf,
device_state: UsbDeviceState::Disabled,
suspended: false,
remote_wakeup_enabled: false,
self_powered: false,
pending_address: 0,
interfaces,
}
}
/// Runs the `UsbDevice` forever.
///
/// This future may leave the bus in an invalid state if it is dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the
/// peripheral.
pub async fn run(&mut self) -> ! {
loop {
self.run_until_suspend().await;
self.wait_resume().await;
}
}
/// Runs the `UsbDevice` until the bus is suspended.
///
/// This future may leave the bus in an invalid state if it is dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the
/// peripheral.
pub async fn run_until_suspend(&mut self) -> () {
if self.device_state == UsbDeviceState::Disabled {
self.bus.enable().await;
self.device_state = UsbDeviceState::Default;
if let Some(h) = &self.handler {
h.enabled(true);
}
}
loop {
let control_fut = self.control.setup();
let bus_fut = self.bus.poll();
match select(bus_fut, control_fut).await {
Either::First(evt) => {
self.handle_bus_event(evt);
if self.suspended {
return;
}
}
Either::Second(req) => match req {
Setup::DataIn(req, stage) => self.handle_control_in(req, stage).await,
Setup::DataOut(req, stage) => self.handle_control_out(req, stage).await,
},
}
}
}
/// Disables the USB peripheral.
pub async fn disable(&mut self) {
if self.device_state != UsbDeviceState::Disabled {
self.bus.disable().await;
self.device_state = UsbDeviceState::Disabled;
self.suspended = false;
self.remote_wakeup_enabled = false;
if let Some(h) = &self.handler {
h.enabled(false);
}
}
}
/// Waits for a resume condition on the USB bus.
///
/// This future is cancel-safe.
pub async fn wait_resume(&mut self) {
while self.suspended {
let evt = self.bus.poll().await;
self.handle_bus_event(evt);
}
}
/// Initiates a device remote wakeup on the USB bus.
///
/// If the bus is not suspended or remote wakeup is not enabled, an error
/// will be returned.
///
/// This future may leave the bus in an inconsistent state if dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the peripheral.
pub async fn remote_wakeup(&mut self) -> Result<(), RemoteWakeupError> {
if self.suspended && self.remote_wakeup_enabled {
self.bus.remote_wakeup().await?;
self.suspended = false;
if let Some(h) = &self.handler {
h.suspended(false);
}
Ok(())
} else {
Err(RemoteWakeupError::InvalidState)
}
}
fn handle_bus_event(&mut self, evt: Event) {
match evt {
Event::Reset => {
trace!("usb: reset");
self.device_state = UsbDeviceState::Default;
self.suspended = false;
self.remote_wakeup_enabled = false;
self.pending_address = 0;
for iface in self.interfaces.iter_mut() {
iface.current_alt_setting = 0;
if let Some(h) = &mut iface.handler {
h.reset();
h.set_alternate_setting(0);
}
}
if let Some(h) = &self.handler {
h.reset();
}
}
Event::Resume => {
trace!("usb: resume");
self.suspended = false;
if let Some(h) = &self.handler {
h.suspended(false);
}
}
Event::Suspend => {
trace!("usb: suspend");
self.suspended = true;
if let Some(h) = &self.handler {
h.suspended(true);
}
}
}
}
async fn handle_control_out(&mut self, req: Request, stage: DataOutStage) {
const CONFIGURATION_NONE_U16: u16 = CONFIGURATION_NONE as u16;
const CONFIGURATION_VALUE_U16: u16 = CONFIGURATION_VALUE as u16;
let (data, stage) = match self.control.data_out(self.control_buf, stage).await {
Ok(data) => data,
Err(_) => {
warn!("usb: failed to read CONTROL OUT data stage.");
return;
}
};
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match (req.request, req.value) {
(Request::CLEAR_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
self.remote_wakeup_enabled = false;
if let Some(h) = &self.handler {
h.remote_wakeup_enabled(false);
}
self.control.accept(stage)
}
(Request::SET_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
self.remote_wakeup_enabled = true;
if let Some(h) = &self.handler {
h.remote_wakeup_enabled(true);
}
self.control.accept(stage)
}
(Request::SET_ADDRESS, addr @ 1..=127) => {
self.pending_address = addr as u8;
self.bus.set_address(self.pending_address);
self.device_state = UsbDeviceState::Addressed;
if let Some(h) = &self.handler {
h.addressed(self.pending_address);
}
self.control.accept(stage)
}
(Request::SET_CONFIGURATION, CONFIGURATION_VALUE_U16) => {
debug!("SET_CONFIGURATION: configured");
self.device_state = UsbDeviceState::Configured;
// Enable all endpoints of selected alt settings.
foreach_endpoint(self.config_descriptor, |ep| {
let iface = &self.interfaces[ep.interface as usize];
self.bus.endpoint_set_enabled(
ep.ep_address,
iface.current_alt_setting == ep.interface_alt,
);
})
.unwrap();
// Notify handler.
if let Some(h) = &self.handler {
h.configured(true);
}
self.control.accept(stage)
}
(Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => match self.device_state {
UsbDeviceState::Default => self.control.accept(stage),
_ => {
debug!("SET_CONFIGURATION: unconfigured");
self.device_state = UsbDeviceState::Addressed;
// Disable all endpoints.
foreach_endpoint(self.config_descriptor, |ep| {
self.bus.endpoint_set_enabled(ep.ep_address, false);
})
.unwrap();
// Notify handler.
if let Some(h) = &self.handler {
h.configured(false);
}
self.control.accept(stage)
}
},
_ => self.control.reject(),
},
(RequestType::Standard, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return self.control.reject(),
};
match req.request {
Request::SET_INTERFACE => {
let new_altsetting = req.value as u8;
if new_altsetting >= iface.num_alt_settings {
warn!("SET_INTERFACE: trying to select alt setting out of range.");
return self.control.reject();
}
iface.current_alt_setting = new_altsetting;
// Enable/disable EPs of this interface as needed.
foreach_endpoint(self.config_descriptor, |ep| {
if ep.interface == req.index as u8 {
self.bus.endpoint_set_enabled(
ep.ep_address,
iface.current_alt_setting == ep.interface_alt,
);
}
})
.unwrap();
// TODO check it is valid (not out of range)
// TODO actually enable/disable endpoints.
if let Some(handler) = &mut iface.handler {
handler.set_alternate_setting(new_altsetting);
}
self.control.accept(stage)
}
_ => self.control.reject(),
}
}
(RequestType::Standard, Recipient::Endpoint) => match (req.request, req.value) {
(Request::SET_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.endpoint_set_stalled(ep_addr, true);
self.control.accept(stage)
}
(Request::CLEAR_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.endpoint_set_stalled(ep_addr, false);
self.control.accept(stage)
}
_ => self.control.reject(),
},
(RequestType::Class, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return self.control.reject(),
};
match &mut iface.handler {
Some(handler) => match handler.control_out(req, data) {
OutResponse::Accepted => self.control.accept(stage),
OutResponse::Rejected => self.control.reject(),
},
None => self.control.reject(),
}
}
_ => self.control.reject(),
}
}
async fn handle_control_in(&mut self, req: Request, mut stage: DataInStage) {
// If we don't have an address yet, respond with max 1 packet.
// The host doesn't know our EP0 max packet size yet, and might assume
// a full-length packet is a short packet, thinking we're done sending data.
// See https://github.com/hathach/tinyusb/issues/184
const DEVICE_DESCRIPTOR_LEN: u8 = 18;
if self.pending_address == 0
&& self.config.max_packet_size_0 < DEVICE_DESCRIPTOR_LEN
&& (self.config.max_packet_size_0 as usize) < stage.length
{
trace!("received control req while not addressed: capping response to 1 packet.");
stage.length = self.config.max_packet_size_0 as _;
}
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match req.request {
Request::GET_STATUS => {
let mut status: u16 = 0x0000;
if self.self_powered {
status |= 0x0001;
}
if self.remote_wakeup_enabled {
status |= 0x0002;
}
self.control.accept_in(&status.to_le_bytes(), stage).await
}
Request::GET_DESCRIPTOR => self.handle_get_descriptor(req, stage).await,
Request::GET_CONFIGURATION => {
let status = match self.device_state {
UsbDeviceState::Configured => CONFIGURATION_VALUE,
_ => CONFIGURATION_NONE,
};
self.control.accept_in(&status.to_le_bytes(), stage).await
}
_ => self.control.reject(),
},
(RequestType::Standard, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return self.control.reject(),
};
match req.request {
Request::GET_STATUS => {
let status: u16 = 0;
self.control.accept_in(&status.to_le_bytes(), stage).await
}
Request::GET_INTERFACE => {
self.control
.accept_in(&[iface.current_alt_setting], stage)
.await;
}
Request::GET_DESCRIPTOR => match &mut iface.handler {
Some(handler) => match handler.get_descriptor(req, self.control_buf) {
InResponse::Accepted(data) => self.control.accept_in(data, stage).await,
InResponse::Rejected => self.control.reject(),
},
None => self.control.reject(),
},
_ => self.control.reject(),
}
}
(RequestType::Standard, Recipient::Endpoint) => match req.request {
Request::GET_STATUS => {
let ep_addr: EndpointAddress = ((req.index as u8) & 0x8f).into();
let mut status: u16 = 0x0000;
if self.bus.endpoint_is_stalled(ep_addr) {
status |= 0x0001;
}
self.control.accept_in(&status.to_le_bytes(), stage).await
}
_ => self.control.reject(),
},
(RequestType::Class, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return self.control.reject(),
};
match &mut iface.handler {
Some(handler) => match handler.control_in(req, self.control_buf) {
InResponse::Accepted(data) => self.control.accept_in(data, stage).await,
InResponse::Rejected => self.control.reject(),
},
None => self.control.reject(),
}
}
_ => self.control.reject(),
}
}
async fn handle_get_descriptor(&mut self, req: Request, stage: DataInStage) {
let (dtype, index) = req.descriptor_type_index();
match dtype {
descriptor_type::BOS => self.control.accept_in(self.bos_descriptor, stage).await,
descriptor_type::DEVICE => self.control.accept_in(self.device_descriptor, stage).await,
descriptor_type::CONFIGURATION => {
self.control.accept_in(self.config_descriptor, stage).await
}
descriptor_type::STRING => {
if index == 0 {
self.control
.accept_in_writer(req, stage, |w| {
w.write(descriptor_type::STRING, &lang_id::ENGLISH_US.to_le_bytes());
})
.await
} else {
let s = match index {
1 => self.config.manufacturer,
2 => self.config.product,
3 => self.config.serial_number,
_ => {
let _index = StringIndex::new(index);
let _lang_id = req.index;
// TODO
None
}
};
if let Some(s) = s {
self.control
.accept_in_writer(req, stage, |w| w.string(s))
.await
} else {
self.control.reject()
}
}
}
_ => self.control.reject(),
}
}
}