1 files changed, 103 insertions, 0 deletions

diff --git a/embassy-net/src/device.rs b/embassy-net/src/device.rs
new file mode 100644
index 000000000..95a62e792
--- /dev/null
+++ b/embassy-net/src/device.rs
@@ -0,0 +1,103 @@
+use core::task::{Poll, Waker};
+use smoltcp::phy::Device as SmolDevice;
+use smoltcp::phy::DeviceCapabilities;
+use smoltcp::time::Instant as SmolInstant;
+use smoltcp::Result;
+
+use crate::fmt::*;
+use crate::{Packet, PacketBox, PacketBuf};
+
+#[derive(PartialEq, Eq, Clone, Copy)]
+pub enum LinkState {
+    Down,
+    Up,
+}
+
+pub trait Device {
+    fn is_transmit_ready(&mut self) -> bool;
+    fn transmit(&mut self, pkt: PacketBuf);
+    fn receive(&mut self) -> Option<PacketBuf>;
+
+    fn register_waker(&mut self, waker: &Waker);
+    fn capabilities(&mut self) -> DeviceCapabilities;
+    fn link_state(&mut self) -> LinkState;
+}
+
+pub struct DeviceAdapter {
+    pub device: &'static mut dyn Device,
+    caps: DeviceCapabilities,
+}
+
+impl DeviceAdapter {
+    pub(crate) fn new(device: &'static mut dyn Device) -> Self {
+        Self {
+            caps: device.capabilities(),
+            device,
+        }
+    }
+}
+
+impl<'a> SmolDevice<'a> for DeviceAdapter {
+    type RxToken = RxToken;
+    type TxToken = TxToken<'a>;
+
+    fn receive(&'a mut self) -> Option<(Self::RxToken, Self::TxToken)> {
+        let rx_pkt = self.device.receive()?;
+        let tx_pkt = PacketBox::new(Packet::new()).unwrap(); // TODO: not sure about unwrap
+        let rx_token = RxToken { pkt: rx_pkt };
+        let tx_token = TxToken {
+            device: self.device,
+            pkt: tx_pkt,
+        };
+
+        Some((rx_token, tx_token))
+    }
+
+    /// Construct a transmit token.
+    fn transmit(&'a mut self) -> Option<Self::TxToken> {
+        if !self.device.is_transmit_ready() {
+            return None;
+        }
+
+        let tx_pkt = PacketBox::new(Packet::new())?;
+        Some(TxToken {
+            device: self.device,
+            pkt: tx_pkt,
+        })
+    }
+
+    /// Get a description of device capabilities.
+    fn capabilities(&self) -> DeviceCapabilities {
+        self.caps.clone()
+    }
+}
+
+pub struct RxToken {
+    pkt: PacketBuf,
+}
+
+impl smoltcp::phy::RxToken for RxToken {
+    fn consume<R, F>(mut self, _timestamp: SmolInstant, f: F) -> Result<R>
+    where
+        F: FnOnce(&mut [u8]) -> Result<R>,
+    {
+        f(&mut self.pkt)
+    }
+}
+
+pub struct TxToken<'a> {
+    device: &'a mut dyn Device,
+    pkt: PacketBox,
+}
+
+impl<'a> smoltcp::phy::TxToken for TxToken<'a> {
+    fn consume<R, F>(mut self, _timestamp: SmolInstant, len: usize, f: F) -> Result<R>
+    where
+        F: FnOnce(&mut [u8]) -> Result<R>,
+    {
+        let mut buf = self.pkt.slice(0..len);
+        let r = f(&mut buf)?;
+        self.device.transmit(buf);
+        Ok(r)
+    }
+}