wpan: factor mac logic into other mod

embassy-stm32-wpan/src/sub/mac.rs

@@ -0,0 +1,133 @@
+use core::future::poll_fn;
+use core::marker::PhantomData;
+use core::ptr;
+use core::sync::atomic::{AtomicBool, Ordering};
+use core::task::Poll;
+
+use embassy_futures::poll_once;
+use embassy_stm32::ipcc::Ipcc;
+use embassy_sync::waitqueue::AtomicWaker;
+
+use crate::cmd::CmdPacket;
+use crate::consts::TlPacketType;
+use crate::evt::{EvtBox, EvtPacket};
+use crate::mac::commands::MacCommand;
+use crate::mac::event::MacEvent;
+use crate::mac::typedefs::MacError;
+use crate::tables::{MAC_802_15_4_CMD_BUFFER, MAC_802_15_4_NOTIF_RSP_EVT_BUFFER};
+use crate::{channels, evt};
+
+static MAC_WAKER: AtomicWaker = AtomicWaker::new();
+static MAC_EVT_OUT: AtomicBool = AtomicBool::new(false);
+
+pub struct Mac {
+    phantom: PhantomData<Mac>,
+}
+
+impl Mac {
+    pub(crate) fn new() -> Self {
+        Self { phantom: PhantomData }
+    }
+
+    /// `HW_IPCC_MAC_802_15_4_EvtNot`
+    ///
+    /// This function will stall if the previous `EvtBox` has not been dropped
+    pub async fn tl_read(&self) -> EvtBox<Self> {
+        // Wait for the last event box to be dropped
+        poll_fn(|cx| {
+            MAC_WAKER.register(cx.waker());
+            if MAC_EVT_OUT.load(Ordering::SeqCst) {
+                Poll::Pending
+            } else {
+                Poll::Ready(())
+            }
+        })
+        .await;
+
+        // Return a new event box
+        Ipcc::receive(channels::cpu2::IPCC_MAC_802_15_4_NOTIFICATION_ACK_CHANNEL, || unsafe {
+            // The closure is not async, therefore the closure must execute to completion (cannot be dropped)
+            // Therefore, the event box is guaranteed to be cleaned up if it's not leaked
+            MAC_EVT_OUT.store(true, Ordering::SeqCst);
+
+            Some(EvtBox::new(MAC_802_15_4_NOTIF_RSP_EVT_BUFFER.as_mut_ptr() as *mut _))
+        })
+        .await
+    }
+
+    /// `HW_IPCC_MAC_802_15_4_CmdEvtNot`
+    pub async fn tl_write_and_get_response(&self, opcode: u16, payload: &[u8]) -> u8 {
+        self.tl_write(opcode, payload).await;
+        Ipcc::flush(channels::cpu1::IPCC_MAC_802_15_4_CMD_RSP_CHANNEL).await;
+
+        unsafe {
+            let p_event_packet = MAC_802_15_4_CMD_BUFFER.as_ptr() as *const EvtPacket;
+            let p_mac_rsp_evt = &((*p_event_packet).evt_serial.evt.payload) as *const u8;
+
+            ptr::read_volatile(p_mac_rsp_evt)
+        }
+    }
+
+    /// `TL_MAC_802_15_4_SendCmd`
+    pub async fn tl_write(&self, opcode: u16, payload: &[u8]) {
+        Ipcc::send(channels::cpu1::IPCC_MAC_802_15_4_CMD_RSP_CHANNEL, || unsafe {
+            CmdPacket::write_into(
+                MAC_802_15_4_CMD_BUFFER.as_mut_ptr(),
+                TlPacketType::MacCmd,
+                opcode,
+                payload,
+            );
+        })
+        .await;
+    }
+
+    pub async fn send_command<T>(&self, cmd: &T) -> Result<(), MacError>
+    where
+        T: MacCommand,
+    {
+        let mut payload = [0u8; MAX_PACKET_SIZE];
+        cmd.copy_into_slice(&mut payload);
+
+        let response = self
+            .tl_write_and_get_response(T::OPCODE as u16, &payload[..T::SIZE])
+            .await;
+
+        if response == 0x00 {
+            Ok(())
+        } else {
+            Err(MacError::from(response))
+        }
+    }
+
+    pub async fn read(&self) -> Result<MacEvent, ()> {
+        let evt_box = self.tl_read().await;
+        let payload = evt_box.payload();
+
+        MacEvent::try_from(payload)
+    }
+}
+
+const MAX_PACKET_SIZE: usize = 255;
+
+impl evt::MemoryManager for Mac {
+    /// SAFETY: passing a pointer to something other than a managed event packet is UB
+    unsafe fn drop_event_packet(_: *mut EvtPacket) {
+        // Write the ack
+        CmdPacket::write_into(
+            MAC_802_15_4_NOTIF_RSP_EVT_BUFFER.as_mut_ptr() as *mut _,
+            TlPacketType::OtAck,
+            0,
+            &[],
+        );
+
+        // Clear the rx flag
+        let _ = poll_once(Ipcc::receive::<bool>(
+            channels::cpu2::IPCC_MAC_802_15_4_NOTIFICATION_ACK_CHANNEL,
+            || None,
+        ));
+
+        // Allow a new read call
+        MAC_EVT_OUT.store(false, Ordering::SeqCst);
+        MAC_WAKER.wake();
+    }
+}