usb: move all control-related stuff to mod control.

embassy-usb/src/control.rs

@@ -123,3 +123,106 @@ impl Request {
         ((self.value >> 8) as u8, self.value as u8)
     }
 }
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum RequestStatus {
+    Accepted,
+    Rejected,
+}
+
+/// A trait for implementing USB classes.
+///
+/// All methods are optional callbacks that will be called by
+/// [`UsbDevice::run()`](crate::UsbDevice::run)
+pub trait ControlHandler {
+    /// 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(&mut self, req: Request, data: &[u8]) -> RequestStatus {
+        RequestStatus::Rejected
+    }
+
+    /// 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>(
+        &mut self,
+        req: Request,
+        control: ControlIn<'a>,
+    ) -> ControlInRequestStatus<'a> {
+        control.reject()
+    }
+}
+
+/// 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> {
+    buf: &'a mut [u8],
+}
+
+#[derive(Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct ControlInRequestStatus<'a> {
+    pub(crate) status: RequestStatus,
+    pub(crate) data: &'a [u8],
+}
+
+impl<'a> ControlInRequestStatus<'a> {
+    pub fn status(&self) -> RequestStatus {
+        self.status
+    }
+}
+
+impl<'a> ControlIn<'a> {
+    pub(crate) fn new(buf: &'a mut [u8]) -> Self {
+        ControlIn { buf }
+    }
+
+    /// Accepts the transfer with the supplied buffer.
+    pub fn accept(self, data: &[u8]) -> ControlInRequestStatus<'a> {
+        assert!(data.len() < self.buf.len());
+
+        let buf = &mut self.buf[0..data.len()];
+        buf.copy_from_slice(data);
+
+        ControlInRequestStatus {
+            status: RequestStatus::Accepted,
+            data: buf,
+        }
+    }
+
+    /// Rejects the transfer by stalling the pipe.
+    pub fn reject(self) -> ControlInRequestStatus<'a> {
+        ControlInRequestStatus {
+            status: RequestStatus::Rejected,
+            data: &[],
+        }
+    }
+}