Add support for USB classes handling control requests.

embassy-nrf/src/usb.rs

@@ -9,6 +9,7 @@ use embassy::time::{with_timeout, Duration};
 use embassy::util::Unborrow;
 use embassy::waitqueue::AtomicWaker;
 use embassy_hal_common::unborrow;
+use embassy_usb::control::Request;
 use embassy_usb::driver::{self, Event, ReadError, WriteError};
 use embassy_usb::types::{EndpointAddress, EndpointInfo, EndpointType, UsbDirection};
 use futures::future::poll_fn;
@@ -134,6 +135,7 @@ impl<'d, T: Instance> Driver<'d, T> {
 impl<'d, T: Instance> driver::Driver<'d> for Driver<'d, T> {
     type EndpointOut = Endpoint<'d, T, Out>;
     type EndpointIn = Endpoint<'d, T, In>;
+    type ControlPipe = ControlPipe<'d, T>;
     type Bus = Bus<'d, T>;
 
     fn alloc_endpoint_in(
@@ -174,6 +176,19 @@ impl<'d, T: Instance> driver::Driver<'d> for Driver<'d, T> {
         }))
     }
 
+    fn alloc_control_pipe(
+        &mut self,
+        max_packet_size: u16,
+    ) -> Result<Self::ControlPipe, driver::EndpointAllocError> {
+        self.alloc_endpoint_out(Some(0x00.into()), EndpointType::Control, max_packet_size, 0)?;
+        self.alloc_endpoint_in(Some(0x80.into()), EndpointType::Control, max_packet_size, 0)?;
+        Ok(ControlPipe {
+            _phantom: PhantomData,
+            max_packet_size,
+            request: None,
+        })
+    }
+
     fn enable(self) -> Self::Bus {
         let regs = T::regs();
 
@@ -344,49 +359,94 @@ impl<'d, T: Instance, Dir> driver::Endpoint for Endpoint<'d, T, Dir> {
     }
 }
 
+unsafe fn read_dma<T: Instance>(i: usize, buf: &mut [u8]) -> Result<usize, ReadError> {
+    let regs = T::regs();
+
+    // Check that the packet fits into the buffer
+    let size = regs.size.epout[0].read().bits() as usize;
+    if size > buf.len() {
+        return Err(ReadError::BufferOverflow);
+    }
+
+    if i == 0 {
+        regs.events_ep0datadone.reset();
+    }
+
+    let epout = [
+        &regs.epout0,
+        &regs.epout1,
+        &regs.epout2,
+        &regs.epout3,
+        &regs.epout4,
+        &regs.epout5,
+        &regs.epout6,
+        &regs.epout7,
+    ];
+    epout[i].ptr.write(|w| w.bits(buf.as_ptr() as u32));
+    // MAXCNT must match SIZE
+    epout[i].maxcnt.write(|w| w.bits(size as u32));
+
+    dma_start();
+    regs.events_endepout[i].reset();
+    regs.tasks_startepout[i].write(|w| w.tasks_startepout().set_bit());
+    while regs.events_endepout[i]
+        .read()
+        .events_endepout()
+        .bit_is_clear()
+    {}
+    regs.events_endepout[i].reset();
+    dma_end();
+
+    regs.size.epout[i].reset();
+
+    Ok(size)
+}
+
+unsafe fn write_dma<T: Instance>(i: usize, buf: &[u8]) -> Result<(), WriteError> {
+    let regs = T::regs();
+    if buf.len() > 64 {
+        return Err(WriteError::BufferOverflow);
+    }
+
+    // EasyDMA can't read FLASH, so we copy through RAM
+    let mut ram_buf: MaybeUninit<[u8; 64]> = MaybeUninit::uninit();
+    let ptr = ram_buf.as_mut_ptr() as *mut u8;
+    core::ptr::copy_nonoverlapping(buf.as_ptr(), ptr, buf.len());
+
+    let epin = [
+        &regs.epin0,
+        &regs.epin1,
+        &regs.epin2,
+        &regs.epin3,
+        &regs.epin4,
+        &regs.epin5,
+        &regs.epin6,
+        &regs.epin7,
+    ];
+
+    // Set the buffer length so the right number of bytes are transmitted.
+    // Safety: `buf.len()` has been checked to be <= the max buffer length.
+    epin[i].ptr.write(|w| w.bits(ptr as u32));
+    epin[i].maxcnt.write(|w| w.maxcnt().bits(buf.len() as u8));
+
+    regs.events_endepin[i].reset();
+
+    dma_start();
+    regs.tasks_startepin[i].write(|w| w.bits(1));
+    while regs.events_endepin[i].read().bits() == 0 {}
+    dma_end();
+
+    Ok(())
+}
+
 impl<'d, T: Instance> driver::EndpointOut for Endpoint<'d, T, Out> {
     type ReadFuture<'a> = impl Future<Output = Result<usize, ReadError>> + 'a where Self: 'a;
 
     fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
         async move {
-            let regs = T::regs();
             let i = self.info.addr.index();
+            assert!(i != 0);
 
-            if i == 0 {
-                if buf.len() == 0 {
-                    regs.tasks_ep0status.write(|w| unsafe { w.bits(1) });
-                    return Ok(0);
-                }
-
-                // Wait for SETUP packet
-                regs.events_ep0setup.reset();
-                regs.intenset.write(|w| w.ep0setup().set());
-                poll_fn(|cx| {
-                    EP_OUT_WAKERS[0].register(cx.waker());
-                    let regs = T::regs();
-                    if regs.events_ep0setup.read().bits() != 0 {
-                        Poll::Ready(())
-                    } else {
-                        Poll::Pending
-                    }
-                })
-                .await;
-
-                if buf.len() < 8 {
-                    return Err(ReadError::BufferOverflow);
-                }
-
-                buf[0] = regs.bmrequesttype.read().bits() as u8;
-                buf[1] = regs.brequest.read().brequest().bits();
-                buf[2] = regs.wvaluel.read().wvaluel().bits();
-                buf[3] = regs.wvalueh.read().wvalueh().bits();
-                buf[4] = regs.windexl.read().windexl().bits();
-                buf[5] = regs.windexh.read().windexh().bits();
-                buf[6] = regs.wlengthl.read().wlengthl().bits();
-                buf[7] = regs.wlengthh.read().wlengthh().bits();
-
-                Ok(8)
-            } else {
             // Wait until ready
             poll_fn(|cx| {
                 EP_OUT_WAKERS[i].register(cx.waker());
@@ -402,41 +462,7 @@ impl<'d, T: Instance> driver::EndpointOut for Endpoint<'d, T, Out> {
             // Mark as not ready
             READY_ENDPOINTS.fetch_and(!(1 << (i + 16)), Ordering::AcqRel);
 
-                // Check that the packet fits into the buffer
+            unsafe { read_dma::<T>(i, buf) }
-                let size = regs.size.epout[i].read().bits();
-                if size as usize > buf.len() {
-                    return Err(ReadError::BufferOverflow);
-                }
-
-                let epout = [
-                    &regs.epout0,
-                    &regs.epout1,
-                    &regs.epout2,
-                    &regs.epout3,
-                    &regs.epout4,
-                    &regs.epout5,
-                    &regs.epout6,
-                    &regs.epout7,
-                ];
-                epout[i]
-                    .ptr
-                    .write(|w| unsafe { w.bits(buf.as_ptr() as u32) });
-                // MAXCNT must match SIZE
-                epout[i].maxcnt.write(|w| unsafe { w.bits(size) });
-
-                dma_start();
-                regs.events_endepout[i].reset();
-                regs.tasks_startepout[i].write(|w| w.tasks_startepout().set_bit());
-                while regs.events_endepout[i]
-                    .read()
-                    .events_endepout()
-                    .bit_is_clear()
-                {}
-                regs.events_endepout[i].reset();
-                dma_end();
-
-                Ok(size as usize)
-            }
         }
     }
 }
@@ -446,11 +472,10 @@ impl<'d, T: Instance> driver::EndpointIn for Endpoint<'d, T, In> {
 
     fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
         async move {
-            let regs = T::regs();
             let i = self.info.addr.index();
+            assert!(i != 0);
 
             // Wait until ready.
-            if i != 0 {
             poll_fn(|cx| {
                 EP_IN_WAKERS[i].register(cx.waker());
                 let r = READY_ENDPOINTS.load(Ordering::Acquire);
@@ -464,45 +489,29 @@ impl<'d, T: Instance> driver::EndpointIn for Endpoint<'d, T, In> {
 
             // Mark as not ready
             READY_ENDPOINTS.fetch_and(!(1 << i), Ordering::AcqRel);
+
+            unsafe { write_dma::<T>(i, buf) }
+        }
+    }
 }
 
-            if i == 0 {
+pub struct ControlPipe<'d, T: Instance> {
+    _phantom: PhantomData<&'d mut T>,
+    max_packet_size: u16,
+    request: Option<Request>,
+}
+
+impl<'d, T: Instance> ControlPipe<'d, T> {
+    async fn write(&mut self, buf: &[u8], last_chunk: bool) {
+        let regs = T::regs();
         regs.events_ep0datadone.reset();
-            }
-
-            assert!(buf.len() <= 64);
-
-            // EasyDMA can't read FLASH, so we copy through RAM
-            let mut ram_buf: MaybeUninit<[u8; 64]> = MaybeUninit::uninit();
-            let ptr = ram_buf.as_mut_ptr() as *mut u8;
-            unsafe { core::ptr::copy_nonoverlapping(buf.as_ptr(), ptr, buf.len()) };
-
-            let epin = [
-                &regs.epin0,
-                &regs.epin1,
-                &regs.epin2,
-                &regs.epin3,
-                &regs.epin4,
-                &regs.epin5,
-                &regs.epin6,
-                &regs.epin7,
-            ];
-
-            // Set the buffer length so the right number of bytes are transmitted.
-            // Safety: `buf.len()` has been checked to be <= the max buffer length.
         unsafe {
-                epin[i].ptr.write(|w| w.bits(ptr as u32));
+            write_dma::<T>(0, buf).unwrap();
-                epin[i].maxcnt.write(|w| w.maxcnt().bits(buf.len() as u8));
         }
 
-            regs.events_endepin[i].reset();
+        regs.shorts
+            .modify(|_, w| w.ep0datadone_ep0status().bit(last_chunk));
 
-            dma_start();
-            regs.tasks_startepin[i].write(|w| unsafe { w.bits(1) });
-            while regs.events_endepin[i].read().bits() == 0 {}
-            dma_end();
-
-            if i == 0 {
         regs.intenset.write(|w| w.ep0datadone().set());
         let res = with_timeout(
             Duration::from_millis(10),
@@ -519,13 +528,124 @@ impl<'d, T: Instance> driver::EndpointIn for Endpoint<'d, T, In> {
         .await;
 
         if res.is_err() {
-                    // todo wrong error
+            error!("ControlPipe::write timed out.");
-                    return Err(driver::WriteError::BufferOverflow);
+        }
     }
 }
 
-            Ok(())
+impl<'d, T: Instance> driver::ControlPipe for ControlPipe<'d, T> {
+    type SetupFuture<'a> = impl Future<Output = Request> + 'a where Self: 'a;
+    type DataOutFuture<'a> = impl Future<Output = Result<usize, ReadError>> + 'a where Self: 'a;
+    type AcceptInFuture<'a> = impl Future<Output = ()> + 'a where Self: 'a;
+
+    fn setup<'a>(&'a mut self) -> Self::SetupFuture<'a> {
+        async move {
+            assert!(self.request.is_none());
+
+            let regs = T::regs();
+
+            // Wait for SETUP packet
+            regs.intenset.write(|w| w.ep0setup().set());
+            poll_fn(|cx| {
+                EP_OUT_WAKERS[0].register(cx.waker());
+                let regs = T::regs();
+                if regs.events_ep0setup.read().bits() != 0 {
+                    Poll::Ready(())
+                } else {
+                    Poll::Pending
                 }
+            })
+            .await;
+
+            // Reset shorts
+            regs.shorts
+                .modify(|_, w| w.ep0datadone_ep0status().clear_bit());
+            regs.events_ep0setup.reset();
+
+            let mut buf = [0; 8];
+            buf[0] = regs.bmrequesttype.read().bits() as u8;
+            buf[1] = regs.brequest.read().brequest().bits();
+            buf[2] = regs.wvaluel.read().wvaluel().bits();
+            buf[3] = regs.wvalueh.read().wvalueh().bits();
+            buf[4] = regs.windexl.read().windexl().bits();
+            buf[5] = regs.windexh.read().windexh().bits();
+            buf[6] = regs.wlengthl.read().wlengthl().bits();
+            buf[7] = regs.wlengthh.read().wlengthh().bits();
+
+            let req = Request::parse(&buf);
+
+            if req.direction == UsbDirection::Out {
+                regs.tasks_ep0rcvout
+                    .write(|w| w.tasks_ep0rcvout().set_bit());
+            }
+
+            self.request = Some(req);
+            req
+        }
+    }
+
+    fn data_out<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::DataOutFuture<'a> {
+        async move {
+            let req = self.request.unwrap();
+            assert_eq!(req.direction, UsbDirection::Out);
+            assert!(req.length > 0);
+            assert!(buf.len() >= usize::from(req.length));
+
+            let regs = T::regs();
+
+            // Wait until ready
+            regs.intenset.write(|w| w.ep0datadone().set());
+            poll_fn(|cx| {
+                EP_OUT_WAKERS[0].register(cx.waker());
+                let regs = T::regs();
+                if regs
+                    .events_ep0datadone
+                    .read()
+                    .events_ep0datadone()
+                    .bit_is_set()
+                {
+                    Poll::Ready(())
+                } else {
+                    Poll::Pending
+                }
+            })
+            .await;
+
+            unsafe { read_dma::<T>(0, buf) }
+        }
+    }
+
+    fn accept(&mut self) {
+        let regs = T::regs();
+        regs.tasks_ep0status
+            .write(|w| w.tasks_ep0status().bit(true));
+        self.request = None;
+    }
+
+    fn accept_in<'a>(&'a mut self, buf: &'a [u8]) -> Self::AcceptInFuture<'a> {
+        async move {
+            info!("control accept {=[u8]:x}", buf);
+            let req = self.request.unwrap();
+            assert_eq!(req.direction, UsbDirection::In);
+
+            let req_len = usize::from(req.length);
+            let len = buf.len().min(req_len);
+            let need_zlp = len != req_len && (len % usize::from(self.max_packet_size)) == 0;
+            let mut chunks = buf[0..len]
+                .chunks(usize::from(self.max_packet_size))
+                .chain(need_zlp.then(|| -> &[u8] { &[] }));
+            while let Some(chunk) = chunks.next() {
+                self.write(chunk, chunks.size_hint().0 == 0).await;
+            }
+
+            self.request = None;
+        }
+    }
+
+    fn reject(&mut self) {
+        let regs = T::regs();
+        regs.tasks_ep0stall.write(|w| w.tasks_ep0stall().bit(true));
+        self.request = None;
     }
 }
 

embassy-usb/src/builder.rs

@@ -1,3 +1,4 @@
+use super::class::UsbClass;
 use super::descriptor::{BosWriter, DescriptorWriter};
 use super::driver::{Driver, EndpointAllocError};
 use super::types::*;
@@ -174,7 +175,10 @@ impl<'d, D: Driver<'d>> UsbDeviceBuilder<'d, D> {
     }
 
     /// Creates the [`UsbDevice`] instance with the configuration in this builder.
-    pub fn build(mut self) -> UsbDevice<'d, D> {
+    ///
+    /// If a device has mutliple [`UsbClass`]es, they can be provided as a tuple list:
+    /// `(class1, (class2, (class3, ()))`.
+    pub fn build<C: UsbClass<'d, D>>(mut self, classes: C) -> UsbDevice<'d, D, C> {
         self.config_descriptor.end_configuration();
         self.bos_descriptor.end_bos();
 
@@ -184,6 +188,7 @@ impl<'d, D: Driver<'d>> UsbDeviceBuilder<'d, D> {
             self.device_descriptor.into_buf(),
             self.config_descriptor.into_buf(),
             self.bos_descriptor.writer.into_buf(),
+            classes,
         )
     }
 
@@ -268,9 +273,10 @@ impl<'d, D: Driver<'d>> UsbDeviceBuilder<'d, D> {
     /// Panics if endpoint allocation fails, because running out of endpoints or memory is not
     /// feasibly recoverable.
     #[inline]
-    pub fn alloc_control_endpoint_out(&mut self, max_packet_size: u16) -> D::EndpointOut {
+    pub fn alloc_control_pipe(&mut self, max_packet_size: u16) -> D::ControlPipe {
-        self.alloc_endpoint_out(None, EndpointType::Control, max_packet_size, 0)
+        self.bus
-            .expect("alloc_ep failed")
+            .alloc_control_pipe(max_packet_size)
+            .expect("alloc_control_pipe failed")
     }
 
     /// Allocates a bulk in endpoint.

embassy-usb/src/class.rs

@@ -0,0 +1,190 @@
+use core::future::Future;
+
+use crate::control::Request;
+use crate::driver::{ControlPipe, Driver};
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum RequestStatus {
+    Unhandled,
+    Accepted,
+    Rejected,
+}
+
+impl Default for RequestStatus {
+    fn default() -> Self {
+        RequestStatus::Unhandled
+    }
+}
+
+/// A trait for implementing USB classes.
+///
+/// All methods are optional callbacks that will be called by
+/// [`UsbDevice::run()`](crate::UsbDevice::run)
+pub trait UsbClass<'d, D: Driver<'d>> {
+    type ControlOutFuture<'a>: Future<Output = RequestStatus> + 'a
+    where
+        Self: 'a,
+        'd: 'a,
+        D: 'a;
+
+    type ControlInFuture<'a>: Future<Output = ControlInRequestStatus> + 'a
+    where
+        Self: 'a,
+        'd: 'a,
+        D: 'a;
+
+    /// Called after a USB reset after the bus reset sequence is complete.
+    fn reset(&mut self) {}
+
+    /// Called when a control request is received with direction HostToDevice.
+    ///
+    /// All requests are passed to classes in turn, which can choose to accept, ignore or report an
+    /// error. Classes can even choose to override standard requests, but doing that is rarely
+    /// necessary.
+    ///
+    /// When implementing your own class, you should ignore any requests that are not meant for your
+    /// class so that any other classes in the composite device can process them.
+    ///
+    /// # Arguments
+    ///
+    /// * `req` - The request from the SETUP packet.
+    /// * `data` - The data from the request.
+    fn control_out<'a>(&'a mut self, req: Request, data: &'a [u8]) -> Self::ControlOutFuture<'a>
+    where
+        'd: 'a,
+        D: 'a;
+
+    /// Called when a control request is received with direction DeviceToHost.
+    ///
+    /// All requests are passed to classes in turn, which can choose to accept, ignore or report an
+    /// error. Classes can even choose to override standard requests, but doing that is rarely
+    /// necessary.
+    ///
+    /// See [`ControlIn`] for how to respond to the transfer.
+    ///
+    /// When implementing your own class, you should ignore any requests that are not meant for your
+    /// class so that any other classes in the composite device can process them.
+    ///
+    /// # Arguments
+    ///
+    /// * `req` - The request from the SETUP packet.
+    /// * `control` - The control pipe.
+    fn control_in<'a>(
+        &'a mut self,
+        req: Request,
+        control: ControlIn<'a, 'd, D>,
+    ) -> Self::ControlInFuture<'a>
+    where
+        'd: 'a;
+}
+
+impl<'d, D: Driver<'d>> UsbClass<'d, D> for () {
+    type ControlOutFuture<'a> = impl Future<Output = RequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+    type ControlInFuture<'a> = impl Future<Output = ControlInRequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+
+    fn control_out<'a>(&'a mut self, _req: Request, _data: &'a [u8]) -> Self::ControlOutFuture<'a>
+    where
+        'd: 'a,
+        D: 'a,
+    {
+        async move { RequestStatus::default() }
+    }
+
+    fn control_in<'a>(
+        &'a mut self,
+        _req: Request,
+        control: ControlIn<'a, 'd, D>,
+    ) -> Self::ControlInFuture<'a>
+    where
+        'd: 'a,
+        D: 'a,
+    {
+        async move { control.ignore() }
+    }
+}
+
+impl<'d, D: Driver<'d>, Head, Tail> UsbClass<'d, D> for (Head, Tail)
+where
+    Head: UsbClass<'d, D>,
+    Tail: UsbClass<'d, D>,
+{
+    type ControlOutFuture<'a> = impl Future<Output = RequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+    type ControlInFuture<'a> = impl Future<Output = ControlInRequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+
+    fn control_out<'a>(&'a mut self, req: Request, data: &'a [u8]) -> Self::ControlOutFuture<'a>
+    where
+        'd: 'a,
+        D: 'a,
+    {
+        async move {
+            match self.0.control_out(req, data).await {
+                RequestStatus::Unhandled => self.1.control_out(req, data).await,
+                status => status,
+            }
+        }
+    }
+
+    fn control_in<'a>(
+        &'a mut self,
+        req: Request,
+        control: ControlIn<'a, 'd, D>,
+    ) -> Self::ControlInFuture<'a>
+    where
+        'd: 'a,
+    {
+        async move {
+            match self
+                .0
+                .control_in(req, ControlIn::new(control.control))
+                .await
+            {
+                ControlInRequestStatus(RequestStatus::Unhandled) => {
+                    self.1.control_in(req, control).await
+                }
+                status => status,
+            }
+        }
+    }
+}
+
+/// Handle for a control IN transfer. When implementing a class, use the methods of this object to
+/// response to the transfer with either data or an error (STALL condition). To ignore the request
+/// and pass it on to the next class, call [`Self::ignore()`].
+pub struct ControlIn<'a, 'd: 'a, D: Driver<'d>> {
+    control: &'a mut D::ControlPipe,
+}
+
+#[derive(Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct ControlInRequestStatus(pub(crate) RequestStatus);
+
+impl ControlInRequestStatus {
+    pub fn status(self) -> RequestStatus {
+        self.0
+    }
+}
+
+impl<'a, 'd: 'a, D: Driver<'d>> ControlIn<'a, 'd, D> {
+    pub(crate) fn new(control: &'a mut D::ControlPipe) -> Self {
+        ControlIn { control }
+    }
+
+    /// Ignores the request and leaves it unhandled.
+    pub fn ignore(self) -> ControlInRequestStatus {
+        ControlInRequestStatus(RequestStatus::Unhandled)
+    }
+
+    /// Accepts the transfer with the supplied buffer.
+    pub async fn accept(self, data: &[u8]) -> ControlInRequestStatus {
+        self.control.accept_in(data).await;
+
+        ControlInRequestStatus(RequestStatus::Accepted)
+    }
+
+    /// Rejects the transfer by stalling the pipe.
+    pub fn reject(self) -> ControlInRequestStatus {
+        self.control.reject();
+        ControlInRequestStatus(RequestStatus::Rejected)
+    }
+}

embassy-usb/src/control.rs

@@ -2,12 +2,6 @@ use core::mem;
 
 use super::types::*;
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub enum ParseError {
-    InvalidLength,
-}
-
 /// Control request type.
 #[repr(u8)]
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
@@ -104,15 +98,12 @@ impl Request {
     /// Standard USB feature Device Remote Wakeup for Set/Clear Feature
     pub const FEATURE_DEVICE_REMOTE_WAKEUP: u16 = 1;
 
-    pub(crate) fn parse(buf: &[u8]) -> Result<Request, ParseError> {
+    /// Parses a USB control request from a byte array.
-        if buf.len() != 8 {
+    pub fn parse(buf: &[u8; 8]) -> Request {
-            return Err(ParseError::InvalidLength);
-        }
-
         let rt = buf[0];
         let recipient = rt & 0b11111;
 
-        Ok(Request {
+        Request {
             direction: rt.into(),
             request_type: unsafe { mem::transmute((rt >> 5) & 0b11) },
             recipient: if recipient <= 3 {
@@ -124,7 +115,7 @@ impl Request {
             value: (buf[2] as u16) | ((buf[3] as u16) << 8),
             index: (buf[4] as u16) | ((buf[5] as u16) << 8),
             length: (buf[6] as u16) | ((buf[7] as u16) << 8),
-        })
+        }
     }
 
     /// Gets the descriptor type and index from the value field of a GET_DESCRIPTOR request.

embassy-usb/src/driver.rs

@@ -1,5 +1,7 @@
 use core::future::Future;
 
+use crate::control::Request;
+
 use super::types::*;
 
 /// Driver for a specific USB peripheral. Implement this to add support for a new hardware
@@ -7,6 +9,7 @@ use super::types::*;
 pub trait Driver<'a> {
     type EndpointOut: EndpointOut + 'a;
     type EndpointIn: EndpointIn + 'a;
+    type ControlPipe: ControlPipe + 'a;
     type Bus: Bus + 'a;
 
     /// Allocates an endpoint and specified endpoint parameters. This method is called by the device
@@ -36,6 +39,11 @@ pub trait Driver<'a> {
         interval: u8,
     ) -> Result<Self::EndpointIn, EndpointAllocError>;
 
+    fn alloc_control_pipe(
+        &mut self,
+        max_packet_size: u16,
+    ) -> Result<Self::ControlPipe, EndpointAllocError>;
+
     /// Enables and initializes the USB peripheral. Soon after enabling the device will be reset, so
     /// there is no need to perform a USB reset in this method.
     fn enable(self) -> Self::Bus;
@@ -122,6 +130,40 @@ pub trait EndpointOut: Endpoint {
     fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a>;
 }
 
+pub trait ControlPipe {
+    type SetupFuture<'a>: Future<Output = Request> + 'a
+    where
+        Self: 'a;
+    type DataOutFuture<'a>: Future<Output = Result<usize, ReadError>> + 'a
+    where
+        Self: 'a;
+    type AcceptInFuture<'a>: Future<Output = ()> + 'a
+    where
+        Self: 'a;
+
+    /// Reads a single setup packet from the endpoint.
+    fn setup<'a>(&'a mut self) -> Self::SetupFuture<'a>;
+
+    /// Reads the data packet of a control write sequence.
+    ///
+    /// Must be called after `setup()` for requests with `direction` of `Out`
+    /// and `length` greater than zero.
+    ///
+    /// `buf.len()` must be greater than or equal to the request's `length`.
+    fn data_out<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::DataOutFuture<'a>;
+
+    /// Accepts a control request.
+    fn accept(&mut self);
+
+    /// Accepts a control read request with `data`.
+    ///
+    /// `data.len()` must be less than or equal to the request's `length`.
+    fn accept_in<'a>(&'a mut self, data: &'a [u8]) -> Self::AcceptInFuture<'a>;
+
+    /// Rejects a control request.
+    fn reject(&mut self);
+}
+
 pub trait EndpointIn: Endpoint {
     type WriteFuture<'a>: Future<Output = Result<(), WriteError>> + 'a
     where

embassy-usb/src/lib.rs

@@ -1,16 +1,19 @@
 #![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;
-mod control;
+pub mod class;
+pub mod control;
 pub mod descriptor;
 pub mod driver;
 pub mod types;
 mod util;
 
+use self::class::{RequestStatus, UsbClass};
 use self::control::*;
 use self::descriptor::*;
 use self::driver::*;
@@ -48,10 +51,9 @@ pub const CONFIGURATION_VALUE: u8 = 1;
 /// The default value for bAlternateSetting for all interfaces.
 pub const DEFAULT_ALTERNATE_SETTING: u8 = 0;
 
-pub struct UsbDevice<'d, D: Driver<'d>> {
+pub struct UsbDevice<'d, D: Driver<'d>, C: UsbClass<'d, D>> {
     bus: D::Bus,
-    control_in: D::EndpointIn,
+    control: D::ControlPipe,
-    control_out: D::EndpointOut,
 
     config: Config<'d>,
     device_descriptor: &'d [u8],
@@ -62,32 +64,21 @@ pub struct UsbDevice<'d, D: Driver<'d>> {
     remote_wakeup_enabled: bool,
     self_powered: bool,
     pending_address: u8,
+
+    classes: C,
 }
 
-impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
+impl<'d, D: Driver<'d>, C: UsbClass<'d, D>> UsbDevice<'d, D, C> {
     pub(crate) fn build(
         mut driver: D,
         config: Config<'d>,
         device_descriptor: &'d [u8],
         config_descriptor: &'d [u8],
         bos_descriptor: &'d [u8],
+        classes: C,
     ) -> Self {
-        let control_out = driver
+        let control = driver
-            .alloc_endpoint_out(
+            .alloc_control_pipe(config.max_packet_size_0 as u16)
-                Some(0x00.into()),
-                EndpointType::Control,
-                config.max_packet_size_0 as u16,
-                0,
-            )
-            .expect("failed to alloc control endpoint");
-
-        let control_in = driver
-            .alloc_endpoint_in(
-                Some(0x80.into()),
-                EndpointType::Control,
-                config.max_packet_size_0 as u16,
-                0,
-            )
             .expect("failed to alloc control endpoint");
 
         // Enable the USB bus.
@@ -97,8 +88,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         Self {
             bus: driver,
             config,
-            control_in,
+            control,
-            control_out,
             device_descriptor,
             config_descriptor,
             bos_descriptor,
@@ -106,14 +96,13 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
             remote_wakeup_enabled: false,
             self_powered: false,
             pending_address: 0,
+            classes,
         }
     }
 
     pub async fn run(&mut self) {
-        let mut buf = [0; 8];
-
         loop {
-            let control_fut = self.control_out.read(&mut buf);
+            let control_fut = self.control.setup();
             let bus_fut = self.bus.poll();
             match select(bus_fut, control_fut).await {
                 Either::Left(evt) => match evt {
@@ -124,11 +113,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         self.remote_wakeup_enabled = false;
                         self.pending_address = 0;
 
-                        // TODO
+                        self.classes.reset();
-                        //self.control.reset();
-                        //for cls in classes {
-                        //    cls.reset();
-                        //}
                     }
                     Event::Resume => {}
                     Event::Suspend => {
@@ -136,16 +121,9 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         self.device_state = UsbDeviceState::Suspend;
                     }
                 },
-                Either::Right(n) => {
+                Either::Right(req) => {
-                    let n = n.unwrap();
-                    assert_eq!(n, 8);
-                    let req = Request::parse(&buf).unwrap();
                     info!("control request: {:x}", req);
 
-                    // Now that we have properly parsed the setup packet, ensure the end-point is no longer in
-                    // a stalled state.
-                    self.control_out.set_stalled(false);
-
                     match req.direction {
                         UsbDirection::In => self.handle_control_in(req).await,
                         UsbDirection::Out => self.handle_control_out(req).await,
@@ -155,36 +133,6 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         }
     }
 
-    async fn write_chunked(&mut self, data: &[u8]) -> Result<(), driver::WriteError> {
-        for c in data.chunks(8) {
-            self.control_in.write(c).await?;
-        }
-        if data.len() % 8 == 0 {
-            self.control_in.write(&[]).await?;
-        }
-        Ok(())
-    }
-
-    async fn control_out_accept(&mut self, req: Request) {
-        info!("control out accept");
-        // status phase
-        // todo: cleanup
-        self.control_out.read(&mut []).await.unwrap();
-    }
-
-    async fn control_in_accept(&mut self, req: Request, data: &[u8]) {
-        info!("control accept {:x}", data);
-
-        let len = data.len().min(req.length as _);
-        if let Err(e) = self.write_chunked(&data[..len]).await {
-            info!("write_chunked failed: {:?}", e);
-        }
-
-        // status phase
-        // todo: cleanup
-        self.control_out.read(&mut []).await.unwrap();
-    }
-
     async fn control_in_accept_writer(
         &mut self,
         req: Request,
@@ -193,17 +141,26 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         let mut buf = [0; 256];
         let mut w = DescriptorWriter::new(&mut buf);
         f(&mut w);
-        let pos = w.position();
+        let pos = w.position().min(usize::from(req.length));
-        self.control_in_accept(req, &buf[..pos]).await;
+        self.control.accept_in(&buf[..pos]).await;
-    }
-
-    fn control_reject(&mut self, req: Request) {
-        info!("control reject");
-        self.control_out.set_stalled(true);
     }
 
     async fn handle_control_out(&mut self, req: Request) {
-        // TODO actually read the data if there's an OUT data phase.
+        {
+            let mut buf = [0; 128];
+            let data = if req.length > 0 {
+                let size = self.control.data_out(&mut buf).await.unwrap();
+                &buf[0..size]
+            } else {
+                &[]
+            };
+
+            match self.classes.control_out(req, data).await {
+                RequestStatus::Accepted => return self.control.accept(),
+                RequestStatus::Rejected => return self.control.reject(),
+                RequestStatus::Unhandled => (),
+            }
+        }
 
         const CONFIGURATION_NONE_U16: u16 = CONFIGURATION_NONE as u16;
         const CONFIGURATION_VALUE_U16: u16 = CONFIGURATION_VALUE as u16;
@@ -217,12 +174,12 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     Request::FEATURE_DEVICE_REMOTE_WAKEUP,
                 ) => {
                     self.remote_wakeup_enabled = false;
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (Recipient::Endpoint, Request::CLEAR_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
                     //self.bus.set_stalled(((req.index as u8) & 0x8f).into(), false);
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (
@@ -231,51 +188,61 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     Request::FEATURE_DEVICE_REMOTE_WAKEUP,
                 ) => {
                     self.remote_wakeup_enabled = true;
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (Recipient::Endpoint, Request::SET_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
                     self.bus
                         .set_stalled(((req.index as u8) & 0x8f).into(), true);
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (Recipient::Device, Request::SET_ADDRESS, 1..=127) => {
                     self.pending_address = req.value as u8;
 
                     // on NRF the hardware auto-handles SET_ADDRESS.
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (Recipient::Device, Request::SET_CONFIGURATION, CONFIGURATION_VALUE_U16) => {
                     self.device_state = UsbDeviceState::Configured;
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
                 (Recipient::Device, Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => {
                     match self.device_state {
                         UsbDeviceState::Default => {
-                            self.control_out_accept(req).await;
+                            self.control.accept();
                         }
                         _ => {
                             self.device_state = UsbDeviceState::Addressed;
-                            self.control_out_accept(req).await;
+                            self.control.accept();
                         }
                     }
                 }
 
                 (Recipient::Interface, Request::SET_INTERFACE, DEFAULT_ALTERNATE_SETTING_U16) => {
                     // TODO: do something when alternate settings are implemented
-                    self.control_out_accept(req).await;
+                    self.control.accept();
                 }
 
-                _ => self.control_reject(req),
+                _ => self.control.reject(),
             },
-            _ => self.control_reject(req),
+            _ => self.control.reject(),
         }
     }
 
     async fn handle_control_in(&mut self, req: Request) {
+        match self
+            .classes
+            .control_in(req, class::ControlIn::new(&mut self.control))
+            .await
+            .status()
+        {
+            RequestStatus::Accepted | RequestStatus::Rejected => return,
+            RequestStatus::Unhandled => (),
+        }
+
         match req.request_type {
             RequestType::Standard => match (req.recipient, req.request) {
                 (Recipient::Device, Request::GET_STATUS) => {
@@ -286,12 +253,12 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if self.remote_wakeup_enabled {
                         status |= 0x0002;
                     }
-                    self.control_in_accept(req, &status.to_le_bytes()).await;
+                    self.control.accept_in(&status.to_le_bytes()).await;
                 }
 
                 (Recipient::Interface, Request::GET_STATUS) => {
                     let status: u16 = 0x0000;
-                    self.control_in_accept(req, &status.to_le_bytes()).await;
+                    self.control.accept_in(&status.to_le_bytes()).await;
                 }
 
                 (Recipient::Endpoint, Request::GET_STATUS) => {
@@ -300,7 +267,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if self.bus.is_stalled(ep_addr) {
                         status |= 0x0001;
                     }
-                    self.control_in_accept(req, &status.to_le_bytes()).await;
+                    self.control.accept_in(&status.to_le_bytes()).await;
                 }
 
                 (Recipient::Device, Request::GET_DESCRIPTOR) => {
@@ -312,17 +279,17 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         UsbDeviceState::Configured => CONFIGURATION_VALUE,
                         _ => CONFIGURATION_NONE,
                     };
-                    self.control_in_accept(req, &status.to_le_bytes()).await;
+                    self.control.accept_in(&status.to_le_bytes()).await;
                 }
 
                 (Recipient::Interface, Request::GET_INTERFACE) => {
                     // TODO: change when alternate settings are implemented
                     let status = DEFAULT_ALTERNATE_SETTING;
-                    self.control_in_accept(req, &status.to_le_bytes()).await;
+                    self.control.accept_in(&status.to_le_bytes()).await;
                 }
-                _ => self.control_reject(req),
+                _ => self.control.reject(),
             },
-            _ => self.control_reject(req),
+            _ => self.control.reject(),
         }
     }
 
@@ -331,11 +298,9 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         let config = self.config.clone();
 
         match dtype {
-            descriptor_type::BOS => self.control_in_accept(req, self.bos_descriptor).await,
+            descriptor_type::BOS => self.control.accept_in(self.bos_descriptor).await,
-            descriptor_type::DEVICE => self.control_in_accept(req, self.device_descriptor).await,
+            descriptor_type::DEVICE => self.control.accept_in(self.device_descriptor).await,
-            descriptor_type::CONFIGURATION => {
+            descriptor_type::CONFIGURATION => self.control.accept_in(self.config_descriptor).await,
-                self.control_in_accept(req, self.config_descriptor).await
-            }
             descriptor_type::STRING => {
                 if index == 0 {
                     self.control_in_accept_writer(req, |w| {
@@ -363,11 +328,11 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         self.control_in_accept_writer(req, |w| w.string(s).unwrap())
                             .await;
                     } else {
-                        self.control_reject(req)
+                        self.control.reject()
                     }
                 }
             }
-            _ => self.control_reject(req),
+            _ => self.control.reject(),
         }
     }
 }

examples/nrf/src/bin/usb/cdc_acm.rs

@@ -1,5 +1,8 @@
-use core::convert::TryInto;
+use core::future::Future;
 use core::mem;
+use defmt::info;
+use embassy_usb::class::{ControlInRequestStatus, RequestStatus, UsbClass};
+use embassy_usb::control::{self, Request};
 use embassy_usb::driver::{Endpoint, EndpointIn, EndpointOut, ReadError, WriteError};
 use embassy_usb::{driver::Driver, types::*, UsbDeviceBuilder};
 
@@ -39,16 +42,107 @@ const REQ_SET_CONTROL_LINE_STATE: u8 = 0x22;
 ///   terminated with a short packet, even if the bulk endpoint is used for stream-like data.
 pub struct CdcAcmClass<'d, D: Driver<'d>> {
     // TODO not pub
-    pub comm_if: InterfaceNumber,
     pub comm_ep: D::EndpointIn,
     pub data_if: InterfaceNumber,
     pub read_ep: D::EndpointOut,
     pub write_ep: D::EndpointIn,
+    pub control: CdcAcmControl,
+}
+
+pub struct CdcAcmControl {
+    pub comm_if: InterfaceNumber,
     pub line_coding: LineCoding,
     pub dtr: bool,
     pub rts: bool,
 }
 
+impl<'d, D: Driver<'d>> UsbClass<'d, D> for CdcAcmControl {
+    type ControlOutFuture<'a> = impl Future<Output = RequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+    type ControlInFuture<'a> = impl Future<Output = ControlInRequestStatus> + 'a where Self: 'a, 'd: 'a, D: 'a;
+
+    fn reset(&mut self) {
+        self.line_coding = LineCoding::default();
+        self.dtr = false;
+        self.rts = false;
+    }
+
+    fn control_out<'a>(
+        &'a mut self,
+        req: control::Request,
+        data: &'a [u8],
+    ) -> Self::ControlOutFuture<'a>
+    where
+        'd: 'a,
+        D: 'a,
+    {
+        async move {
+            if !(req.request_type == control::RequestType::Class
+                && req.recipient == control::Recipient::Interface
+                && req.index == u8::from(self.comm_if) as u16)
+            {
+                return RequestStatus::Unhandled;
+            }
+
+            match req.request {
+                REQ_SEND_ENCAPSULATED_COMMAND => {
+                    // We don't actually support encapsulated commands but pretend we do for standards
+                    // compatibility.
+                    RequestStatus::Accepted
+                }
+                REQ_SET_LINE_CODING if data.len() >= 7 => {
+                    self.line_coding.data_rate = u32::from_le_bytes(data[0..4].try_into().unwrap());
+                    self.line_coding.stop_bits = data[4].into();
+                    self.line_coding.parity_type = data[5].into();
+                    self.line_coding.data_bits = data[6];
+                    info!("Set line coding to: {:?}", self.line_coding);
+
+                    RequestStatus::Accepted
+                }
+                REQ_SET_CONTROL_LINE_STATE => {
+                    self.dtr = (req.value & 0x0001) != 0;
+                    self.rts = (req.value & 0x0002) != 0;
+                    info!("Set dtr {}, rts {}", self.dtr, self.rts);
+
+                    RequestStatus::Accepted
+                }
+                _ => RequestStatus::Rejected,
+            }
+        }
+    }
+
+    fn control_in<'a>(
+        &'a mut self,
+        req: Request,
+        control: embassy_usb::class::ControlIn<'a, 'd, D>,
+    ) -> Self::ControlInFuture<'a>
+    where
+        'd: 'a,
+    {
+        async move {
+            if !(req.request_type == control::RequestType::Class
+                && req.recipient == control::Recipient::Interface
+                && req.index == u8::from(self.comm_if) as u16)
+            {
+                return control.ignore();
+            }
+
+            match req.request {
+                // REQ_GET_ENCAPSULATED_COMMAND is not really supported - it will be rejected below.
+                REQ_GET_LINE_CODING if req.length == 7 => {
+                    info!("Sending line coding");
+                    let mut data = [0; 7];
+                    data[0..4].copy_from_slice(&self.line_coding.data_rate.to_le_bytes());
+                    data[4] = self.line_coding.stop_bits as u8;
+                    data[5] = self.line_coding.parity_type as u8;
+                    data[6] = self.line_coding.data_bits;
+                    control.accept(&data).await
+                }
+                _ => control.reject(),
+            }
+        }
+    }
+}
+
 impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
     /// Creates a new CdcAcmClass with the provided UsbBus and max_packet_size in bytes. For
     /// full-speed devices, max_packet_size has to be one of 8, 16, 32 or 64.
@@ -133,19 +227,21 @@ impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
         builder.config_descriptor.endpoint(read_ep.info()).unwrap();
 
         CdcAcmClass {
-            comm_if,
             comm_ep,
             data_if,
             read_ep,
             write_ep,
+            control: CdcAcmControl {
+                comm_if,
+                dtr: false,
+                rts: false,
                 line_coding: LineCoding {
                     stop_bits: StopBits::One,
                     data_bits: 8,
                     parity_type: ParityType::None,
                     data_rate: 8_000,
                 },
-            dtr: false,
+            },
-            rts: false,
         }
     }
 
@@ -158,17 +254,17 @@ impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
     /// Gets the current line coding. The line coding contains information that's mainly relevant
     /// for USB to UART serial port emulators, and can be ignored if not relevant.
     pub fn line_coding(&self) -> &LineCoding {
-        &self.line_coding
+        &self.control.line_coding
     }
 
     /// Gets the DTR (data terminal ready) state
     pub fn dtr(&self) -> bool {
-        self.dtr
+        self.control.dtr
     }
 
     /// Gets the RTS (request to send) state
     pub fn rts(&self) -> bool {
-        self.rts
+        self.control.rts
     }
 
     /// Writes a single packet into the IN endpoint.
@@ -270,7 +366,7 @@ impl<B: UsbBus> UsbClass<B> for CdcAcmClass<'_, B> {
  */
 
 /// Number of stop bits for LineCoding
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, defmt::Format)]
 pub enum StopBits {
     /// 1 stop bit
     One = 0,
@@ -293,7 +389,7 @@ impl From<u8> for StopBits {
 }
 
 /// Parity for LineCoding
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, defmt::Format)]
 pub enum ParityType {
     None = 0,
     Odd = 1,
@@ -316,6 +412,7 @@ impl From<u8> for ParityType {
 ///
 /// This is provided by the host for specifying the standard UART parameters such as baud rate. Can
 /// be ignored if you don't plan to interface with a physical UART.
+#[derive(defmt::Format)]
 pub struct LineCoding {
     stop_bits: StopBits,
     data_bits: u8,

examples/nrf/src/bin/usb/main.rs

@@ -1,5 +1,6 @@
 #![no_std]
 #![no_main]
+#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 #[path = "../../example_common.rs"]
@@ -58,7 +59,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     let mut class = CdcAcmClass::new(&mut builder, 64);
 
     // Build the builder.
-    let mut usb = builder.build();
+    let mut usb = builder.build(class.control);
 
     // Run the USB device.
     let fut1 = usb.run();