usb: move classes into the `embassy-usb` crate.

1 files changed, 354 insertions, 0 deletions

diff --git a/embassy-usb/src/class/cdc_acm.rs b/embassy-usb/src/class/cdc_acm.rs
new file mode 100644
index 000000000..09bb1cc8d
--- /dev/null
+++ b/embassy-usb/src/class/cdc_acm.rs
@@ -0,0 +1,354 @@
+use core::cell::Cell;
+use core::mem::{self, MaybeUninit};
+use core::sync::atomic::{AtomicBool, Ordering};
+
+use embassy_sync::blocking_mutex::CriticalSectionMutex;
+
+use crate::control::{self, ControlHandler, InResponse, OutResponse, Request};
+use crate::driver::{Driver, Endpoint, EndpointError, EndpointIn, EndpointOut};
+use crate::types::*;
+use crate::Builder;
+
+/// This should be used as `device_class` when building the `UsbDevice`.
+pub const USB_CLASS_CDC: u8 = 0x02;
+
+const USB_CLASS_CDC_DATA: u8 = 0x0a;
+const CDC_SUBCLASS_ACM: u8 = 0x02;
+const CDC_PROTOCOL_NONE: u8 = 0x00;
+
+const CS_INTERFACE: u8 = 0x24;
+const CDC_TYPE_HEADER: u8 = 0x00;
+const CDC_TYPE_CALL_MANAGEMENT: u8 = 0x01;
+const CDC_TYPE_ACM: u8 = 0x02;
+const CDC_TYPE_UNION: u8 = 0x06;
+
+const REQ_SEND_ENCAPSULATED_COMMAND: u8 = 0x00;
+#[allow(unused)]
+const REQ_GET_ENCAPSULATED_COMMAND: u8 = 0x01;
+const REQ_SET_LINE_CODING: u8 = 0x20;
+const REQ_GET_LINE_CODING: u8 = 0x21;
+const REQ_SET_CONTROL_LINE_STATE: u8 = 0x22;
+
+pub struct State<'a> {
+    control: MaybeUninit<Control<'a>>,
+    shared: ControlShared,
+}
+
+impl<'a> State<'a> {
+    pub fn new() -> Self {
+        Self {
+            control: MaybeUninit::uninit(),
+            shared: Default::default(),
+        }
+    }
+}
+
+/// Packet level implementation of a CDC-ACM serial port.
+///
+/// This class can be used directly and it has the least overhead due to directly reading and
+/// writing USB packets with no intermediate buffers, but it will not act like a stream-like serial
+/// port. The following constraints must be followed if you use this class directly:
+///
+/// - `read_packet` must be called with a buffer large enough to hold max_packet_size bytes.
+/// - `write_packet` must not be called with a buffer larger than max_packet_size bytes.
+/// - If you write a packet that is exactly max_packet_size bytes long, it won't be processed by the
+///   host operating system until a subsequent shorter packet is sent. A zero-length packet (ZLP)
+///   can be sent if there is no other data to send. This is because USB bulk transactions must be
+///   terminated with a short packet, even if the bulk endpoint is used for stream-like data.
+pub struct CdcAcmClass<'d, D: Driver<'d>> {
+    _comm_ep: D::EndpointIn,
+    _data_if: InterfaceNumber,
+    read_ep: D::EndpointOut,
+    write_ep: D::EndpointIn,
+    control: &'d ControlShared,
+}
+
+struct Control<'a> {
+    shared: &'a ControlShared,
+}
+
+/// Shared data between Control and CdcAcmClass
+struct ControlShared {
+    line_coding: CriticalSectionMutex<Cell<LineCoding>>,
+    dtr: AtomicBool,
+    rts: AtomicBool,
+}
+
+impl Default for ControlShared {
+    fn default() -> Self {
+        ControlShared {
+            dtr: AtomicBool::new(false),
+            rts: AtomicBool::new(false),
+            line_coding: CriticalSectionMutex::new(Cell::new(LineCoding {
+                stop_bits: StopBits::One,
+                data_bits: 8,
+                parity_type: ParityType::None,
+                data_rate: 8_000,
+            })),
+        }
+    }
+}
+
+impl<'a> Control<'a> {
+    fn shared(&mut self) -> &'a ControlShared {
+        self.shared
+    }
+}
+
+impl<'d> ControlHandler for Control<'d> {
+    fn reset(&mut self) {
+        let shared = self.shared();
+        shared.line_coding.lock(|x| x.set(LineCoding::default()));
+        shared.dtr.store(false, Ordering::Relaxed);
+        shared.rts.store(false, Ordering::Relaxed);
+    }
+
+    fn control_out(&mut self, req: control::Request, data: &[u8]) -> OutResponse {
+        match req.request {
+            REQ_SEND_ENCAPSULATED_COMMAND => {
+                // We don't actually support encapsulated commands but pretend we do for standards
+                // compatibility.
+                OutResponse::Accepted
+            }
+            REQ_SET_LINE_CODING if data.len() >= 7 => {
+                let coding = LineCoding {
+                    data_rate: u32::from_le_bytes(data[0..4].try_into().unwrap()),
+                    stop_bits: data[4].into(),
+                    parity_type: data[5].into(),
+                    data_bits: data[6],
+                };
+                self.shared().line_coding.lock(|x| x.set(coding));
+                debug!("Set line coding to: {:?}", coding);
+
+                OutResponse::Accepted
+            }
+            REQ_SET_CONTROL_LINE_STATE => {
+                let dtr = (req.value & 0x0001) != 0;
+                let rts = (req.value & 0x0002) != 0;
+
+                let shared = self.shared();
+                shared.dtr.store(dtr, Ordering::Relaxed);
+                shared.rts.store(rts, Ordering::Relaxed);
+                debug!("Set dtr {}, rts {}", dtr, rts);
+
+                OutResponse::Accepted
+            }
+            _ => OutResponse::Rejected,
+        }
+    }
+
+    fn control_in<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
+        match req.request {
+            // REQ_GET_ENCAPSULATED_COMMAND is not really supported - it will be rejected below.
+            REQ_GET_LINE_CODING if req.length == 7 => {
+                debug!("Sending line coding");
+                let coding = self.shared().line_coding.lock(|x| x.get());
+                assert!(buf.len() >= 7);
+                buf[0..4].copy_from_slice(&coding.data_rate.to_le_bytes());
+                buf[4] = coding.stop_bits as u8;
+                buf[5] = coding.parity_type as u8;
+                buf[6] = coding.data_bits;
+                InResponse::Accepted(&buf[0..7])
+            }
+            _ => InResponse::Rejected,
+        }
+    }
+}
+
+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.
+    pub fn new(builder: &mut Builder<'d, D>, state: &'d mut State<'d>, max_packet_size: u16) -> Self {
+        let control = state.control.write(Control { shared: &state.shared });
+
+        let control_shared = &state.shared;
+
+        assert!(builder.control_buf_len() >= 7);
+
+        let mut func = builder.function(USB_CLASS_CDC, CDC_SUBCLASS_ACM, CDC_PROTOCOL_NONE);
+
+        // Control interface
+        let mut iface = func.interface();
+        iface.handler(control);
+        let comm_if = iface.interface_number();
+        let data_if = u8::from(comm_if) + 1;
+        let mut alt = iface.alt_setting(USB_CLASS_CDC, CDC_SUBCLASS_ACM, CDC_PROTOCOL_NONE);
+
+        alt.descriptor(
+            CS_INTERFACE,
+            &[
+                CDC_TYPE_HEADER, // bDescriptorSubtype
+                0x10,
+                0x01, // bcdCDC (1.10)
+            ],
+        );
+        alt.descriptor(
+            CS_INTERFACE,
+            &[
+                CDC_TYPE_ACM, // bDescriptorSubtype
+                0x00,         // bmCapabilities
+            ],
+        );
+        alt.descriptor(
+            CS_INTERFACE,
+            &[
+                CDC_TYPE_UNION, // bDescriptorSubtype
+                comm_if.into(), // bControlInterface
+                data_if.into(), // bSubordinateInterface
+            ],
+        );
+        alt.descriptor(
+            CS_INTERFACE,
+            &[
+                CDC_TYPE_CALL_MANAGEMENT, // bDescriptorSubtype
+                0x00,                     // bmCapabilities
+                data_if.into(),           // bDataInterface
+            ],
+        );
+
+        let comm_ep = alt.endpoint_interrupt_in(8, 255);
+
+        // Data interface
+        let mut iface = func.interface();
+        let data_if = iface.interface_number();
+        let mut alt = iface.alt_setting(USB_CLASS_CDC_DATA, 0x00, CDC_PROTOCOL_NONE);
+        let read_ep = alt.endpoint_bulk_out(max_packet_size);
+        let write_ep = alt.endpoint_bulk_in(max_packet_size);
+
+        CdcAcmClass {
+            _comm_ep: comm_ep,
+            _data_if: data_if,
+            read_ep,
+            write_ep,
+            control: control_shared,
+        }
+    }
+
+    /// Gets the maximum packet size in bytes.
+    pub fn max_packet_size(&self) -> u16 {
+        // The size is the same for both endpoints.
+        self.read_ep.info().max_packet_size
+    }
+
+    /// 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.control.line_coding.lock(|x| x.get())
+    }
+
+    /// Gets the DTR (data terminal ready) state
+    pub fn dtr(&self) -> bool {
+        self.control.dtr.load(Ordering::Relaxed)
+    }
+
+    /// Gets the RTS (request to send) state
+    pub fn rts(&self) -> bool {
+        self.control.rts.load(Ordering::Relaxed)
+    }
+
+    /// Writes a single packet into the IN endpoint.
+    pub async fn write_packet(&mut self, data: &[u8]) -> Result<(), EndpointError> {
+        self.write_ep.write(data).await
+    }
+
+    /// Reads a single packet from the OUT endpoint.
+    pub async fn read_packet(&mut self, data: &mut [u8]) -> Result<usize, EndpointError> {
+        self.read_ep.read(data).await
+    }
+
+    /// Waits for the USB host to enable this interface
+    pub async fn wait_connection(&mut self) {
+        self.read_ep.wait_enabled().await
+    }
+}
+
+/// Number of stop bits for LineCoding
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum StopBits {
+    /// 1 stop bit
+    One = 0,
+
+    /// 1.5 stop bits
+    OnePointFive = 1,
+
+    /// 2 stop bits
+    Two = 2,
+}
+
+impl From<u8> for StopBits {
+    fn from(value: u8) -> Self {
+        if value <= 2 {
+            unsafe { mem::transmute(value) }
+        } else {
+            StopBits::One
+        }
+    }
+}
+
+/// Parity for LineCoding
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum ParityType {
+    None = 0,
+    Odd = 1,
+    Even = 2,
+    Mark = 3,
+    Space = 4,
+}
+
+impl From<u8> for ParityType {
+    fn from(value: u8) -> Self {
+        if value <= 4 {
+            unsafe { mem::transmute(value) }
+        } else {
+            ParityType::None
+        }
+    }
+}
+
+/// Line coding parameters
+///
+/// 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(Clone, Copy, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct LineCoding {
+    stop_bits: StopBits,
+    data_bits: u8,
+    parity_type: ParityType,
+    data_rate: u32,
+}
+
+impl LineCoding {
+    /// Gets the number of stop bits for UART communication.
+    pub fn stop_bits(&self) -> StopBits {
+        self.stop_bits
+    }
+
+    /// Gets the number of data bits for UART communication.
+    pub fn data_bits(&self) -> u8 {
+        self.data_bits
+    }
+
+    /// Gets the parity type for UART communication.
+    pub fn parity_type(&self) -> ParityType {
+        self.parity_type
+    }
+
+    /// Gets the data rate in bits per second for UART communication.
+    pub fn data_rate(&self) -> u32 {
+        self.data_rate
+    }
+}
+
+impl Default for LineCoding {
+    fn default() -> Self {
+        LineCoding {
+            stop_bits: StopBits::One,
+            data_bits: 8,
+            parity_type: ParityType::None,
+            data_rate: 8_000,
+        }
+    }
+}