subkernel: port master support

src/libboard_artiq/src/drtioaux_proto.rs

@@ -1,8 +1,11 @@
 use core_io::{Error as IoError, Read, Write};
 use io::proto::{ProtoRead, ProtoWrite};
 
-pub const DMA_TRACE_MAX_SIZE: usize = /*max size*/512 - /*CRC*/4 - /*packet ID*/1 - /*trace ID*/4 - /*last*/1 -/*length*/2;
+// maximum size of arbitrary payloads
-pub const ANALYZER_MAX_SIZE: usize  = /*max size*/512 - /*CRC*/4 - /*packet ID*/1 - /*last*/1 - /*length*/2;
+// used by satellite -> master analyzer, subkernel exceptions
+pub const SAT_PAYLOAD_MAX_SIZE: usize  = /*max size*/512 - /*CRC*/4 - /*packet ID*/1 - /*last*/1 - /*length*/2;
+// used by DDMA, subkernel program data (need to provide extra ID and destination)
+pub const MASTER_PAYLOAD_MAX_SIZE: usize = SAT_PAYLOAD_MAX_SIZE - /*destination*/1 - /*ID*/4;
 
 #[derive(Debug)]
 pub enum Error {
@@ -150,7 +153,7 @@ pub enum Packet {
     AnalyzerData {
         last: bool,
         length: u16,
-        data: [u8; ANALYZER_MAX_SIZE],
+        data: [u8; SAT_PAYLOAD_MAX_SIZE],
     },
 
     DmaAddTraceRequest {
@@ -158,7 +161,7 @@ pub enum Packet {
         id: u32,
         last: bool,
         length: u16,
-        trace: [u8; DMA_TRACE_MAX_SIZE],
+        trace: [u8; MASTER_PAYLOAD_MAX_SIZE],
     },
     DmaAddTraceReply {
         succeeded: bool,
@@ -185,6 +188,53 @@ pub enum Packet {
         channel: u32,
         timestamp: u64,
     },
+
+    SubkernelAddDataRequest {
+        destination: u8,
+        id: u32,
+        last: bool,
+        length: u16,
+        data: [u8; MASTER_PAYLOAD_MAX_SIZE],
+    },
+    SubkernelAddDataReply {
+        succeeded: bool,
+    },
+    SubkernelLoadRunRequest {
+        destination: u8,
+        id: u32,
+        run: bool,
+    },
+    SubkernelLoadRunReply {
+        succeeded: bool,
+    },
+    SubkernelStopRequest {
+        destination: u8,
+    },
+    SubkernelStopReply {
+        succeeded: bool,
+    },
+    SubkernelFinished {
+        id: u32,
+        with_exception: bool,
+    },
+    SubkernelExceptionRequest {
+        destination: u8,
+    },
+    SubkernelException {
+        last: bool,
+        length: u16,
+        data: [u8; SAT_PAYLOAD_MAX_SIZE],
+    },
+    SubkernelMessage {
+        destination: u8,
+        id: u32,
+        last: bool,
+        length: u16,
+        data: [u8; MASTER_PAYLOAD_MAX_SIZE],
+    },
+    SubkernelMessageAck {
+        destination: u8,
+    },
 }
 
 impl Packet {
@@ -329,7 +379,7 @@ impl Packet {
             0xa3 => {
                 let last = reader.read_bool()?;
                 let length = reader.read_u16()?;
-                let mut data: [u8; ANALYZER_MAX_SIZE] = [0; ANALYZER_MAX_SIZE];
+                let mut data: [u8; SAT_PAYLOAD_MAX_SIZE] = [0; SAT_PAYLOAD_MAX_SIZE];
                 reader.read_exact(&mut data[0..length as usize])?;
                 Packet::AnalyzerData {
                     last: last,
@@ -343,7 +393,7 @@ impl Packet {
                 let id = reader.read_u32()?;
                 let last = reader.read_bool()?;
                 let length = reader.read_u16()?;
-                let mut trace: [u8; DMA_TRACE_MAX_SIZE] = [0; DMA_TRACE_MAX_SIZE];
+                let mut trace: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
                 reader.read_exact(&mut trace[0..length as usize])?;
                 Packet::DmaAddTraceRequest {
                     destination: destination,
@@ -379,6 +429,75 @@ impl Packet {
                 timestamp: reader.read_u64()?,
             },
 
+            0xc0 => {
+                let destination = reader.read_u8()?;
+                let id = reader.read_u32()?;
+                let last = reader.read_bool()?;
+                let length = reader.read_u16()?;
+                let mut data: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
+                reader.read_exact(&mut data[0..length as usize])?;
+                Packet::SubkernelAddDataRequest {
+                    destination: destination,
+                    id: id,
+                    last: last,
+                    length: length as u16,
+                    data: data,
+                }
+            }
+            0xc1 => Packet::SubkernelAddDataReply {
+                succeeded: reader.read_bool()?,
+            },
+            0xc4 => Packet::SubkernelLoadRunRequest {
+                destination: reader.read_u8()?,
+                id: reader.read_u32()?,
+                run: reader.read_bool()?,
+            },
+            0xc5 => Packet::SubkernelLoadRunReply {
+                succeeded: reader.read_bool()?,
+            },
+            0xc6 => Packet::SubkernelStopRequest {
+                destination: reader.read_u8()?,
+            },
+            0xc7 => Packet::SubkernelStopReply {
+                succeeded: reader.read_bool()?,
+            },
+            0xc8 => Packet::SubkernelFinished {
+                id: reader.read_u32()?,
+                with_exception: reader.read_bool()?,
+            },
+            0xc9 => Packet::SubkernelExceptionRequest {
+                destination: reader.read_u8()?,
+            },
+            0xca => {
+                let last = reader.read_bool()?;
+                let length = reader.read_u16()?;
+                let mut data: [u8; SAT_PAYLOAD_MAX_SIZE] = [0; SAT_PAYLOAD_MAX_SIZE];
+                reader.read_exact(&mut data[0..length as usize])?;
+                Packet::SubkernelException {
+                    last: last,
+                    length: length,
+                    data: data,
+                }
+            }
+            0xcb => {
+                let destination = reader.read_u8()?;
+                let id = reader.read_u32()?;
+                let last = reader.read_bool()?;
+                let length = reader.read_u16()?;
+                let mut data: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
+                reader.read_exact(&mut data[0..length as usize])?;
+                Packet::SubkernelMessage {
+                    destination: destination,
+                    id: id,
+                    last: last,
+                    length: length as u16,
+                    data: data,
+                }
+            }
+            0xcc => Packet::SubkernelMessageAck {
+                destination: reader.read_u8()?,
+            },
+
             ty => return Err(Error::UnknownPacket(ty)),
         })
     }
@@ -648,6 +767,76 @@ impl Packet {
                 writer.write_u32(channel)?;
                 writer.write_u64(timestamp)?;
             }
+
+            Packet::SubkernelAddDataRequest {
+                destination,
+                id,
+                last,
+                data,
+                length,
+            } => {
+                writer.write_u8(0xc0)?;
+                writer.write_u8(destination)?;
+                writer.write_u32(id)?;
+                writer.write_bool(last)?;
+                writer.write_u16(length)?;
+                writer.write_all(&data[0..length as usize])?;
+            }
+            Packet::SubkernelAddDataReply { succeeded } => {
+                writer.write_u8(0xc1)?;
+                writer.write_bool(succeeded)?;
+            }
+            Packet::SubkernelLoadRunRequest { destination, id, run } => {
+                writer.write_u8(0xc4)?;
+                writer.write_u8(destination)?;
+                writer.write_u32(id)?;
+                writer.write_bool(run)?;
+            }
+            Packet::SubkernelLoadRunReply { succeeded } => {
+                writer.write_u8(0xc5)?;
+                writer.write_bool(succeeded)?;
+            }
+            Packet::SubkernelStopRequest { destination } => {
+                writer.write_u8(0xc6)?;
+                writer.write_u8(destination)?;
+            }
+            Packet::SubkernelStopReply { succeeded } => {
+                writer.write_u8(0xc7)?;
+                writer.write_bool(succeeded)?;
+            }
+            Packet::SubkernelFinished { id, with_exception } => {
+                writer.write_u8(0xc8)?;
+                writer.write_u32(id)?;
+                writer.write_bool(with_exception)?;
+            }
+            Packet::SubkernelExceptionRequest { destination } => {
+                writer.write_u8(0xc9)?;
+                writer.write_u8(destination)?;
+            }
+            Packet::SubkernelException { last, length, data } => {
+                writer.write_u8(0xca)?;
+                writer.write_bool(last)?;
+                writer.write_u16(length)?;
+                writer.write_all(&data[0..length as usize])?;
+            }
+            Packet::SubkernelMessage {
+                destination,
+                id,
+                last,
+                data,
+                length,
+            } => {
+                writer.write_u8(0xcb)?;
+                writer.write_u8(destination)?;
+                writer.write_u32(id)?;
+                writer.write_bool(last)?;
+                writer.write_u16(length)?;
+                writer.write_all(&data[0..length as usize])?;
+            }
+            Packet::SubkernelMessageAck { destination } => {
+                writer.write_u8(0xcc)?;
+                writer.write_u8(destination)?;
+            }
         }
         Ok(())
     }

src/runtime/src/comms.rs

@@ -1,8 +1,11 @@
 use alloc::{collections::BTreeMap, rc::Rc, string::String, vec, vec::Vec};
 use core::{cell::RefCell, fmt, slice, str};
 
+use core_io::Error as IoError;
 use cslice::CSlice;
 use futures::{future::FutureExt, select_biased};
+#[cfg(has_drtio)]
+use io::{Cursor, ProtoRead};
 use libasync::{smoltcp::{Sockets, TcpStream},
                task};
 use libboard_artiq::drtio_routing;
@@ -28,13 +31,18 @@ use crate::{analyzer, kernel, mgmt, moninj,
             proto_async::*,
             rpc, rtio_dma,
             rtio_mgt::{self, resolve_channel_name}};
+#[cfg(has_drtio)]
+use crate::{subkernel, subkernel::Error as SubkernelError};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Error {
     NetworkError(smoltcp::Error),
+    IoError,
     UnexpectedPattern,
     UnrecognizedPacket,
     BufferExhausted,
+    #[cfg(has_drtio)]
+    SubkernelError(subkernel::Error),
 }
 
 pub type Result<T> = core::result::Result<T, Error>;
@@ -43,9 +51,12 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Error::NetworkError(error) => write!(f, "network error: {}", error),
+            Error::IoError => write!(f, "io error"),
             Error::UnexpectedPattern => write!(f, "unexpected pattern"),
             Error::UnrecognizedPacket => write!(f, "unrecognized packet"),
             Error::BufferExhausted => write!(f, "buffer exhausted"),
+            #[cfg(has_drtio)]
+            Error::SubkernelError(error) => write!(f, "subkernel error: {:?}", error),
         }
     }
 }
@@ -56,6 +67,19 @@ impl From<smoltcp::Error> for Error {
     }
 }
 
+impl From<IoError> for Error {
+    fn from(_error: IoError) -> Self {
+        Error::IoError
+    }
+}
+
+#[cfg(has_drtio)]
+impl From<subkernel::Error> for Error {
+    fn from(error: subkernel::Error) -> Self {
+        Error::SubkernelError(error)
+    }
+}
+
 #[derive(Debug, FromPrimitive, ToPrimitive)]
 enum Request {
     SystemInfo = 3,
@@ -63,6 +87,7 @@ enum Request {
     RunKernel = 6,
     RPCReply = 7,
     RPCException = 8,
+    UploadSubkernel = 9,
 }
 
 #[derive(Debug, FromPrimitive, ToPrimitive)]
@@ -162,6 +187,22 @@ async fn handle_run_kernel(
 ) -> Result<()> {
     control.borrow_mut().tx.async_send(kernel::Message::StartRequest).await;
     loop {
+        #[cfg(has_drtio)]
+        while let Some(subkernel_finished) =
+            subkernel::get_finished_with_exception(aux_mutex, routing_table, timer).await?
+        {
+            if subkernel_finished.status == subkernel::FinishStatus::CommLost {
+                error!(
+                    "Communication with satellite lost while subkernel {} was running",
+                    subkernel_finished.id
+                );
+            }
+            if let Some(exception) = subkernel_finished.exception {
+                if let Some(stream) = stream {
+                    write_chunk(stream, &exception).await?;
+                }
+            }
+        }
         let reply = control.borrow_mut().rx.async_recv().await;
         match reply {
             kernel::Message::RpcSend { is_async, data } => {
@@ -365,6 +406,117 @@ async fn handle_run_kernel(
                 control.borrow_mut().tx.async_send(reply).await;
             }
             #[cfg(has_drtio)]
+            kernel::Message::SubkernelLoadRunRequest { id, run } => {
+                let succeeded = match subkernel::load(aux_mutex, routing_table, timer, id, run).await {
+                    Ok(()) => true,
+                    Err(e) => {
+                        error!("Error loading subkernel: {:?}", e);
+                        false
+                    }
+                };
+                control
+                    .borrow_mut()
+                    .tx
+                    .async_send(kernel::Message::SubkernelLoadRunReply { succeeded: succeeded })
+                    .await;
+            }
+            #[cfg(has_drtio)]
+            kernel::Message::SubkernelAwaitFinishRequest { id, timeout } => {
+                let res = subkernel::await_finish(aux_mutex, routing_table, timer, id, timeout).await;
+                let status = match res {
+                    Ok(ref res) => {
+                        if res.status == subkernel::FinishStatus::CommLost {
+                            kernel::SubkernelStatus::CommLost
+                        } else if let Some(exception) = &res.exception {
+                            error!("Exception in subkernel");
+                            match stream {
+                                None => (),
+                                Some(stream) => {
+                                    write_chunk(stream, exception).await?;
+                                }
+                            }
+                            // will not be called after exception is served
+                            kernel::SubkernelStatus::OtherError
+                        } else {
+                            kernel::SubkernelStatus::NoError
+                        }
+                    }
+                    Err(SubkernelError::Timeout) => kernel::SubkernelStatus::Timeout,
+                    Err(SubkernelError::IncorrectState) => kernel::SubkernelStatus::IncorrectState,
+                    Err(_) => kernel::SubkernelStatus::OtherError,
+                };
+                control
+                    .borrow_mut()
+                    .tx
+                    .async_send(kernel::Message::SubkernelAwaitFinishReply { status: status })
+                    .await;
+            }
+            #[cfg(has_drtio)]
+            kernel::Message::SubkernelMsgSend { id, data } => {
+                let res = subkernel::message_send(aux_mutex, routing_table, timer, id, data).await;
+                match res {
+                    Ok(_) => (),
+                    Err(e) => {
+                        error!("error sending subkernel message: {:?}", e)
+                    }
+                };
+            }
+            #[cfg(has_drtio)]
+            kernel::Message::SubkernelMsgRecvRequest { id, timeout } => {
+                let message_received = subkernel::message_await(id, timeout, timer).await;
+                let status = match message_received {
+                    Ok(_) => kernel::SubkernelStatus::NoError,
+                    Err(SubkernelError::Timeout) => kernel::SubkernelStatus::Timeout,
+                    Err(SubkernelError::IncorrectState) => kernel::SubkernelStatus::IncorrectState,
+                    Err(SubkernelError::CommLost) => kernel::SubkernelStatus::CommLost,
+                    Err(_) => kernel::SubkernelStatus::OtherError,
+                };
+                control
+                    .borrow_mut()
+                    .tx
+                    .async_send(kernel::Message::SubkernelMsgRecvReply { status: status })
+                    .await;
+                if let Ok((tag, data)) = message_received {
+                    // receive code almost identical to RPC recv, except we are not reading from a stream
+                    let mut reader = Cursor::new(data);
+                    let mut tag: [u8; 1] = [tag];
+                    loop {
+                        // kernel has to consume all arguments in the whole message
+                        let slot = match fast_recv(&mut control.borrow_mut().rx).await {
+                            kernel::Message::RpcRecvRequest(slot) => slot,
+                            other => panic!("expected root value slot from core1, not {:?}", other),
+                        };
+                        rpc::recv_return_cursor(&mut reader, &tag, slot, &|size| {
+                            let control = control.clone();
+                            async move {
+                                if size == 0 {
+                                    0 as *mut ()
+                                } else {
+                                    let mut control = control.borrow_mut();
+                                    fast_send(&mut control.tx, kernel::Message::RpcRecvReply(Ok(size))).await;
+                                    match fast_recv(&mut control.rx).await {
+                                        kernel::Message::RpcRecvRequest(slot) => slot,
+                                        other => {
+                                            panic!("expected nested value slot from kernel CPU, not {:?}", other)
+                                        }
+                                    }
+                                }
+                            }
+                        })
+                        .await?;
+                        control
+                            .borrow_mut()
+                            .tx
+                            .async_send(kernel::Message::RpcRecvReply(Ok(0)))
+                            .await;
+                        match reader.read_u8() {
+                            Ok(0) | Err(_) => break, // reached the end of data, we're done
+                            Ok(t) => tag[0] = t,     // update the tag for next read
+                        };
+                    }
+                }
+            }
+            #[cfg(has_drtio)]
             kernel::Message::UpDestinationsRequest(destination) => {
                 let result = _up_destinations.borrow()[destination as usize];
                 control
@@ -434,9 +586,13 @@ async fn handle_connection(
         return Err(Error::UnexpectedPattern);
     }
     stream.send_slice("e".as_bytes()).await?;
+    #[cfg(has_drtio)]
+    subkernel::clear_subkernels().await;
     loop {
         let request = read_request(stream, true).await?;
         if request.is_none() {
+            #[cfg(has_drtio)]
+            subkernel::clear_subkernels().await;
             return Ok(());
         }
         let request = request.unwrap();
@@ -460,6 +616,29 @@ async fn handle_connection(
                 )
                 .await?;
             }
+            Request::UploadSubkernel => {
+                #[cfg(has_drtio)]
+                {
+                    let id = read_i32(stream).await? as u32;
+                    let destination = read_i8(stream).await? as u8;
+                    let buffer = read_bytes(stream, 1024 * 1024).await?;
+                    subkernel::add_subkernel(id, destination, buffer).await;
+                    match subkernel::upload(aux_mutex, routing_table, timer, id).await {
+                        Ok(_) => write_header(stream, Reply::LoadCompleted).await?,
+                        Err(_) => {
+                            write_header(stream, Reply::LoadFailed).await?;
+                            write_chunk(stream, b"subkernel failed to load").await?;
+                            return Err(Error::UnexpectedPattern);
+                        }
+                    }
+                }
+                #[cfg(not(has_drtio))] 
+                {
+                    write_header(stream, Reply::LoadFailed).await?;
+                    write_chunk(stream, b"No DRTIO on this system, subkernels are not supported").await?;
+                    return Err(Error::UnexpectedPattern);
+                }
+            }
             _ => {
                 error!("unexpected request from host: {:?}", request);
                 return Err(Error::UnrecognizedPacket);

src/runtime/src/eh_artiq.rs

@@ -422,7 +422,7 @@ extern "C" fn stop_fn(
 }
 
 // Must be kept in sync with preallocate_runtime_exception_names() in artiq/language/embedding_map.py
-static EXCEPTION_ID_LOOKUP: [(&str, u32); 11] = [
+static EXCEPTION_ID_LOOKUP: [(&str, u32); 12] = [
     ("RuntimeError", 0),
     ("RTIOUnderflow", 1),
     ("RTIOOverflow", 2),
@@ -434,6 +434,7 @@ static EXCEPTION_ID_LOOKUP: [(&str, u32); 11] = [
     ("ZeroDivisionError", 8),
     ("IndexError", 9),
     ("UnwrapNoneError", 10),
+    ("SubkernelError", 11),
 ];
 
 pub fn get_exception_id(name: &str) -> u32 {

src/runtime/src/kernel/api.rs

@@ -9,6 +9,8 @@ use super::{cache,
             core1::rtio_get_destination_status,
             dma,
             rpc::{rpc_recv, rpc_send, rpc_send_async}};
+#[cfg(has_drtio)]
+use super::subkernel;
 use crate::{eh_artiq, i2c, rtio};
 
 extern "C" {
@@ -114,6 +116,16 @@ pub fn resolve(required: &[u8]) -> Option<u32> {
         api!(i2c_read = i2c::read),
         api!(i2c_switch_select = i2c::switch_select),
 
+        // subkernel
+        #[cfg(has_drtio)]
+        api!(subkernel_load_run = subkernel::load_run),
+        #[cfg(has_drtio)]
+        api!(subkernel_await_finish = subkernel::await_finish),
+        #[cfg(has_drtio)]
+        api!(subkernel_send_message = subkernel::send_message),
+        #[cfg(has_drtio)]
+        api!(subkernel_await_message = subkernel::await_message),
+
         // Double-precision floating-point arithmetic helper functions
         // RTABI chapter 4.1.2, Table 2
         api!(__aeabi_dadd),

src/runtime/src/kernel/mod.rs

@@ -13,6 +13,8 @@ mod dma;
 mod rpc;
 pub use dma::DmaRecorder;
 mod cache;
+#[cfg(has_drtio)]
+mod subkernel;
 
 #[derive(Debug, Clone)]
 pub struct RPCException {
@@ -25,6 +27,16 @@ pub struct RPCException {
     pub function: u32,
 }
 
+#[cfg(has_drtio)]
+#[derive(Debug, Clone)]
+pub enum SubkernelStatus {
+    NoError,
+    Timeout,
+    IncorrectState,
+    CommLost,
+    OtherError,
+}
+
 #[derive(Debug, Clone)]
 pub enum Message {
     LoadRequest(Vec<u8>),
@@ -72,6 +84,39 @@ pub enum Message {
     UpDestinationsRequest(i32),
     #[cfg(has_drtio)]
     UpDestinationsReply(bool),
+
+    #[cfg(has_drtio)]
+    SubkernelLoadRunRequest {
+        id: u32,
+        run: bool,
+    },
+    #[cfg(has_drtio)]
+    SubkernelLoadRunReply {
+        succeeded: bool,
+    },
+    #[cfg(has_drtio)]
+    SubkernelAwaitFinishRequest {
+        id: u32,
+        timeout: u64,
+    },
+    #[cfg(has_drtio)]
+    SubkernelAwaitFinishReply {
+        status: SubkernelStatus,
+    },
+    #[cfg(has_drtio)]
+    SubkernelMsgSend {
+        id: u32,
+        data: Vec<u8>,
+    },
+    #[cfg(has_drtio)]
+    SubkernelMsgRecvRequest {
+        id: u32,
+        timeout: u64,
+    },
+    #[cfg(has_drtio)]
+    SubkernelMsgRecvReply {
+        status: SubkernelStatus,
+    },
 }
 
 static CHANNEL_0TO1: Mutex<Option<sync_channel::Sender<'static, Message>>> = Mutex::new(None);

src/runtime/src/kernel/subkernel.rs

@@ -0,0 +1,94 @@
+use alloc::vec::Vec;
+
+use cslice::CSlice;
+
+use super::{Message, SubkernelStatus, KERNEL_CHANNEL_0TO1, KERNEL_CHANNEL_1TO0};
+use crate::{artiq_raise, rpc::send_args};
+
+pub extern "C" fn load_run(id: u32, run: bool) {
+    unsafe {
+        KERNEL_CHANNEL_1TO0
+            .as_mut()
+            .unwrap()
+            .send(Message::SubkernelLoadRunRequest { id: id, run: run });
+    }
+    match unsafe { KERNEL_CHANNEL_0TO1.as_mut().unwrap() }.recv() {
+        Message::SubkernelLoadRunReply { succeeded: true } => (),
+        Message::SubkernelLoadRunReply { succeeded: false } => {
+            artiq_raise!("SubkernelError", "Error loading or running the subkernel")
+        }
+        _ => panic!("Expected SubkernelLoadRunReply after SubkernelLoadRunRequest!"),
+    }
+}
+
+pub extern "C" fn await_finish(id: u32, timeout: u64) {
+    unsafe {
+        KERNEL_CHANNEL_1TO0
+            .as_mut()
+            .unwrap()
+            .send(Message::SubkernelAwaitFinishRequest {
+                id: id,
+                timeout: timeout,
+            });
+    }
+    match unsafe { KERNEL_CHANNEL_0TO1.as_mut().unwrap() }.recv() {
+        Message::SubkernelAwaitFinishReply {
+            status: SubkernelStatus::NoError,
+        } => (),
+        Message::SubkernelAwaitFinishReply {
+            status: SubkernelStatus::IncorrectState,
+        } => artiq_raise!("SubkernelError", "Subkernel not running"),
+        Message::SubkernelAwaitFinishReply {
+            status: SubkernelStatus::Timeout,
+        } => artiq_raise!("SubkernelError", "Subkernel timed out"),
+        Message::SubkernelAwaitFinishReply {
+            status: SubkernelStatus::CommLost,
+        } => artiq_raise!("SubkernelError", "Lost communication with satellite"),
+        Message::SubkernelAwaitFinishReply {
+            status: SubkernelStatus::OtherError,
+        } => artiq_raise!("SubkernelError", "An error occurred during subkernel operation"),
+        _ => panic!("expected SubkernelAwaitFinishReply after SubkernelAwaitFinishRequest"),
+    }
+}
+
+pub extern "C" fn send_message(id: u32, tag: &CSlice<u8>, data: *const *const ()) {
+    let mut buffer = Vec::<u8>::new();
+    send_args(&mut buffer, 0, tag.as_ref(), data).expect("RPC encoding failed");
+    unsafe {
+        KERNEL_CHANNEL_1TO0.as_mut().unwrap().send(Message::SubkernelMsgSend {
+            id: id,
+            data: buffer[4..].to_vec(),
+        });
+    }
+}
+
+pub extern "C" fn await_message(id: u32, timeout: u64) {
+    unsafe {
+        KERNEL_CHANNEL_1TO0
+            .as_mut()
+            .unwrap()
+            .send(Message::SubkernelMsgRecvRequest {
+                id: id,
+                timeout: timeout,
+            });
+    }
+    match unsafe { KERNEL_CHANNEL_0TO1.as_mut().unwrap() }.recv() {
+        Message::SubkernelMsgRecvReply {
+            status: SubkernelStatus::NoError,
+        } => (),
+        Message::SubkernelMsgRecvReply {
+            status: SubkernelStatus::IncorrectState,
+        } => artiq_raise!("SubkernelError", "Subkernel not running"),
+        Message::SubkernelMsgRecvReply {
+            status: SubkernelStatus::Timeout,
+        } => artiq_raise!("SubkernelError", "Subkernel timed out"),
+        Message::SubkernelMsgRecvReply {
+            status: SubkernelStatus::CommLost,
+        } => artiq_raise!("SubkernelError", "Lost communication with satellite"),
+        Message::SubkernelMsgRecvReply {
+            status: SubkernelStatus::OtherError,
+        } => artiq_raise!("SubkernelError", "An error occurred during subkernel operation"),
+        _ => panic!("expected SubkernelMsgRecvReply after SubkernelMsgRecvRequest"),
+    }
+    // RpcRecvRequest should be called after this to receive message data
+}

src/runtime/src/main.rs

@@ -51,6 +51,8 @@ mod rtio;
 mod rtio_clocking;
 mod rtio_dma;
 mod rtio_mgt;
+#[cfg(has_drtio)]
+mod subkernel;
 
 static mut SEEN_ASYNC_ERRORS: u8 = 0;
 

src/runtime/src/rpc.rs

@@ -1,11 +1,15 @@
 use alloc::boxed::Box;
+#[cfg(has_drtio)]
+use alloc::vec::Vec;
 use core::{future::Future, str};
 
 use async_recursion::async_recursion;
 use byteorder::{ByteOrder, NativeEndian};
 use core_io::{Error, Write};
 use cslice::{CMutSlice, CSlice};
-use io::proto::ProtoWrite;
+#[cfg(has_drtio)]
+use io::{Cursor, ProtoRead};
+use io::ProtoWrite;
 use libasync::smoltcp::TcpStream;
 use libboard_zynq::smoltcp;
 use log::trace;
@@ -224,6 +228,173 @@ where
     Ok(())
 }
 
+// versions for Cursor rather than TcpStream
+// they will be made into sync for satellite subkernels later
+#[cfg(has_drtio)]
+#[async_recursion(?Send)]
+async unsafe fn recv_elements_cursor<F>(
+    cursor: &mut Cursor<Vec<u8>>,
+    elt_tag: Tag<'async_recursion>,
+    length: usize,
+    storage: *mut (),
+    alloc: &(impl Fn(usize) -> F + 'async_recursion),
+) -> Result<(), Error>
+where
+    F: Future<Output = *mut ()>,
+{
+    match elt_tag {
+        Tag::Bool => {
+            let dest = core::slice::from_raw_parts_mut(storage as *mut u8, length);
+            cursor.read_exact(dest)?;
+        }
+        Tag::Int32 => {
+            let ptr = storage as *mut u32;
+            let dest = core::slice::from_raw_parts_mut(ptr as *mut u8, length * 4);
+            cursor.read_exact(dest)?;
+            drop(dest);
+            let dest = core::slice::from_raw_parts_mut(ptr, length);
+            NativeEndian::from_slice_u32(dest);
+        }
+        Tag::Int64 | Tag::Float64 => {
+            let ptr = storage as *mut u64;
+            let dest = core::slice::from_raw_parts_mut(ptr as *mut u8, length * 8);
+            cursor.read_exact(dest)?;
+            drop(dest);
+            let dest = core::slice::from_raw_parts_mut(ptr, length);
+            NativeEndian::from_slice_u64(dest);
+        }
+        _ => {
+            let mut data = storage;
+            for _ in 0..length {
+                recv_value_cursor(cursor, elt_tag, &mut data, alloc).await?
+            }
+        }
+    }
+    Ok(())
+}
+
+#[cfg(has_drtio)]
+#[async_recursion(?Send)]
+async unsafe fn recv_value_cursor<F>(
+    cursor: &mut Cursor<Vec<u8>>,
+    tag: Tag<'async_recursion>,
+    data: &mut *mut (),
+    alloc: &(impl Fn(usize) -> F + 'async_recursion),
+) -> Result<(), Error>
+where
+    F: Future<Output = *mut ()>,
+{
+    macro_rules! consume_value {
+        ($ty:ty, | $ptr:ident | $map:expr) => {{
+            let $ptr = align_ptr_mut::<$ty>(*data);
+            *data = $ptr.offset(1) as *mut ();
+            $map
+        }};
+    }
+
+    match tag {
+        Tag::None => Ok(()),
+        Tag::Bool => consume_value!(i8, |ptr| {
+            *ptr = cursor.read_u8()? as i8;
+            Ok(())
+        }),
+        Tag::Int32 => consume_value!(i32, |ptr| {
+            *ptr = cursor.read_u32()? as i32;
+            Ok(())
+        }),
+        Tag::Int64 | Tag::Float64 => consume_value!(i64, |ptr| {
+            *ptr = cursor.read_u64()? as i64;
+            Ok(())
+        }),
+        Tag::String | Tag::Bytes | Tag::ByteArray => {
+            consume_value!(CMutSlice<u8>, |ptr| {
+                let length = cursor.read_u32()? as usize;
+                *ptr = CMutSlice::new(alloc(length).await as *mut u8, length);
+                cursor.read_exact((*ptr).as_mut())?;
+                Ok(())
+            })
+        }
+        Tag::Tuple(it, arity) => {
+            let alignment = tag.alignment();
+            *data = round_up_mut(*data, alignment);
+            let mut it = it.clone();
+            for _ in 0..arity {
+                let tag = it.next().expect("truncated tag");
+                recv_value_cursor(cursor, tag, data, alloc).await?
+            }
+            *data = round_up_mut(*data, alignment);
+            Ok(())
+        }
+        Tag::List(it) => {
+            #[repr(C)]
+            struct List {
+                elements: *mut (),
+                length: usize,
+            }
+            consume_value!(*mut List, |ptr_to_list| {
+                let tag = it.clone().next().expect("truncated tag");
+                let length = cursor.read_u32()? as usize;
+
+                let list_size = 4 + 4;
+                let storage_offset = round_up(list_size, tag.alignment());
+                let storage_size = tag.size() * length;
+
+                let allocation = alloc(storage_offset + storage_size).await as *mut u8;
+                *ptr_to_list = allocation as *mut List;
+                let storage = allocation.offset(storage_offset as isize) as *mut ();
+
+                (**ptr_to_list).length = length;
+                (**ptr_to_list).elements = storage;
+                recv_elements_cursor(cursor, tag, length, storage, alloc).await
+            })
+        }
+        Tag::Array(it, num_dims) => {
+            consume_value!(*mut (), |buffer| {
+                let mut total_len: usize = 1;
+                for _ in 0..num_dims {
+                    let len = cursor.read_u32()? as usize;
+                    total_len *= len;
+                    consume_value!(usize, |ptr| *ptr = len)
+                }
+
+                let elt_tag = it.clone().next().expect("truncated tag");
+                *buffer = alloc(elt_tag.size() * total_len).await;
+                recv_elements_cursor(cursor, elt_tag, total_len, *buffer, alloc).await
+            })
+        }
+        Tag::Range(it) => {
+            *data = round_up_mut(*data, tag.alignment());
+            let tag = it.clone().next().expect("truncated tag");
+            recv_value_cursor(cursor, tag, data, alloc).await?;
+            recv_value_cursor(cursor, tag, data, alloc).await?;
+            recv_value_cursor(cursor, tag, data, alloc).await?;
+            Ok(())
+        }
+        Tag::Keyword(_) => unreachable!(),
+        Tag::Object => unreachable!(),
+    }
+}
+
+#[cfg(has_drtio)]
+pub async fn recv_return_cursor<F>(
+    cursor: &mut Cursor<Vec<u8>>,
+    tag_bytes: &[u8],
+    data: *mut (),
+    alloc: &impl Fn(usize) -> F,
+) -> Result<(), Error>
+where
+    F: Future<Output = *mut ()>,
+{
+    let mut it = TagIterator::new(tag_bytes);
+    trace!("recv ...->{}", it);
+
+    let tag = it.next().expect("truncated tag");
+    let mut data = data;
+    unsafe { recv_value_cursor(cursor, tag, &mut data, alloc).await? };
+
+    Ok(())
+}
+
 unsafe fn send_elements<W>(writer: &mut W, elt_tag: Tag, length: usize, data: *const ()) -> Result<(), Error>
 where W: Write + ?Sized {
     writer.write_u8(elt_tag.as_u8())?;

src/runtime/src/rtio_mgt.rs

@@ -16,12 +16,13 @@ pub mod drtio {
 
     use embedded_hal::blocking::delay::DelayMs;
     use libasync::{delay, task};
-    use libboard_artiq::{drtioaux::Error, drtioaux_async, drtioaux_async::Packet, drtioaux_proto::DMA_TRACE_MAX_SIZE};
+    use libboard_artiq::{drtioaux::Error, drtioaux_async, drtioaux_async::Packet,
+                         drtioaux_proto::MASTER_PAYLOAD_MAX_SIZE};
     use libboard_zynq::time::Milliseconds;
     use log::{error, info, warn};
 
     use super::*;
-    use crate::{analyzer::remote_analyzer::RemoteBuffer, rtio_dma::remote_dma, ASYNC_ERROR_BUSY,
+    use crate::{analyzer::remote_analyzer::RemoteBuffer, rtio_dma::remote_dma, subkernel, ASYNC_ERROR_BUSY,
                 ASYNC_ERROR_COLLISION, ASYNC_ERROR_SEQUENCE_ERROR, SEEN_ASYNC_ERRORS};
 
     pub fn startup(
@@ -44,7 +45,7 @@ pub mod drtio {
         unsafe { (csr::DRTIO[linkno].rx_up_read)() == 1 }
     }
 
-    async fn process_async_packets(packet: Packet) -> Option<Packet> {
+    async fn process_async_packets(linkno: u8, packet: Packet) -> Option<Packet> {
         // returns None if an async packet has been consumed
         match packet {
             Packet::DmaPlaybackStatus {
@@ -57,6 +58,24 @@ pub mod drtio {
                 remote_dma::playback_done(id, destination, error, channel, timestamp).await;
                 None
             }
+            Packet::SubkernelFinished { id, with_exception } => {
+                subkernel::subkernel_finished(id, with_exception).await;
+                None
+            }
+            Packet::SubkernelMessage {
+                id,
+                destination: from,
+                last,
+                length,
+                data,
+            } => {
+                subkernel::message_handle_incoming(id, last, length as usize, &data).await;
+                // acknowledge receiving part of the message
+                drtioaux_async::send(linkno, &Packet::SubkernelMessageAck { destination: from })
+                    .await
+                    .unwrap();
+                None
+            }
             other => Some(other),
         }
     }
@@ -193,7 +212,7 @@ pub mod drtio {
         let _lock = aux_mutex.async_lock().await;
         match drtioaux_async::recv(linkno).await {
             Ok(Some(packet)) => {
-                if let Some(packet) = process_async_packets(packet).await {
+                if let Some(packet) = process_async_packets(linkno, packet).await {
                     warn!("[LINK#{}] unsolicited aux packet: {:?}", linkno, packet);
                 }
             }
@@ -286,6 +305,14 @@ pub mod drtio {
                                         false,
                                     )
                                     .await;
+                                    subkernel::destination_changed(
+                                        aux_mutex,
+                                        routing_table,
+                                        timer,
+                                        destination,
+                                        false,
+                                    )
+                                    .await;
                                 }
                                 Ok(Packet::DestinationOkReply) => (),
                                 Ok(Packet::DestinationSequenceErrorReply { channel }) => {
@@ -328,6 +355,7 @@ pub mod drtio {
                     } else {
                         destination_set_up(routing_table, up_destinations, destination, false).await;
                         remote_dma::destination_changed(aux_mutex, routing_table, timer, destination, false).await;
+                        subkernel::destination_changed(aux_mutex, routing_table, timer, destination, false).await;
                     }
                 } else {
                     if up_links[linkno as usize] {
@@ -347,6 +375,8 @@ pub mod drtio {
                                 init_buffer_space(destination as u8, linkno).await;
                                 remote_dma::destination_changed(aux_mutex, routing_table, timer, destination, true)
                                     .await;
+                                subkernel::destination_changed(aux_mutex, routing_table, timer, destination, true)
+                                    .await;
                             }
                             Ok(packet) => error!("[DEST#{}] received unexpected aux packet: {:?}", destination, packet),
                             Err(e) => error!("[DEST#{}] communication failed ({})", destination, e),
@@ -433,6 +463,36 @@ pub mod drtio {
         }
     }
 
+    async fn partition_data<PacketF, HandlerF>(
+        linkno: u8,
+        aux_mutex: &Rc<Mutex<bool>>,
+        timer: GlobalTimer,
+        data: &[u8],
+        packet_f: PacketF,
+        reply_handler_f: HandlerF,
+    ) -> Result<(), &'static str>
+    where
+        PacketF: Fn(&[u8; MASTER_PAYLOAD_MAX_SIZE], bool, usize) -> Packet,
+        HandlerF: Fn(&Packet) -> Result<(), &'static str>,
+    {
+        let mut i = 0;
+        while i < data.len() {
+            let mut slice: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
+            let len: usize = if i + MASTER_PAYLOAD_MAX_SIZE < data.len() {
+                MASTER_PAYLOAD_MAX_SIZE
+            } else {
+                data.len() - i
+            } as usize;
+            let last = i + len == data.len();
+            slice[..len].clone_from_slice(&data[i..i + len]);
+            i += len;
+            let packet = packet_f(&slice, last, len);
+            let reply = aux_transact(aux_mutex, linkno, &packet, timer).await?;
+            reply_handler_f(&reply)?;
+        }
+        Ok(())
+    }
+
     pub async fn ddma_upload_trace(
         aux_mutex: &Rc<Mutex<bool>>,
         routing_table: &drtio_routing::RoutingTable,
@@ -442,44 +502,25 @@ pub mod drtio {
         trace: &Vec<u8>,
     ) -> Result<(), &'static str> {
         let linkno = routing_table.0[destination as usize][0] - 1;
-        let mut i = 0;
+        partition_data(
-        while i < trace.len() {
-            let mut trace_slice: [u8; DMA_TRACE_MAX_SIZE] = [0; DMA_TRACE_MAX_SIZE];
-            let len: usize = if i + DMA_TRACE_MAX_SIZE < trace.len() {
-                DMA_TRACE_MAX_SIZE
-            } else {
-                trace.len() - i
-            } as usize;
-            let last = i + len == trace.len();
-            trace_slice[..len].clone_from_slice(&trace[i..i + len]);
-            i += len;
-            let reply = aux_transact(
-                aux_mutex,
             linkno,
-                &Packet::DmaAddTraceRequest {
+            aux_mutex,
+            timer,
+            trace,
+            |slice, last, len| Packet::DmaAddTraceRequest {
                 id: id,
                 destination: destination,
                 last: last,
                 length: len as u16,
-                    trace: trace_slice,
+                trace: *slice,
+            },
+            |reply| match reply {
+                Packet::DmaAddTraceReply { succeeded: true } => Ok(()),
+                Packet::DmaAddTraceReply { succeeded: false } => Err("error adding trace on satellite"),
+                _ => Err("adding DMA trace failed, unexpected aux packet"),
             },
-                timer,
         )
-            .await;
+        .await
-            match reply {
-                Ok(Packet::DmaAddTraceReply { succeeded: true }) => (),
-                Ok(Packet::DmaAddTraceReply { succeeded: false }) => {
-                    return Err("error adding trace on satellite");
-                }
-                Ok(_) => {
-                    return Err("adding DMA trace failed, unexpected aux packet");
-                }
-                Err(_) => {
-                    return Err("adding DMA trace failed, aux error");
-                }
-            }
-        }
-        Ok(())
     }
 
     pub async fn ddma_send_erase(
@@ -608,6 +649,122 @@ pub mod drtio {
         }
         Ok(remote_buffers)
     }
+
+    pub async fn subkernel_upload(
+        aux_mutex: &Rc<Mutex<bool>>,
+        routing_table: &drtio_routing::RoutingTable,
+        timer: GlobalTimer,
+        id: u32,
+        destination: u8,
+        data: &Vec<u8>,
+    ) -> Result<(), &'static str> {
+        let linkno = routing_table.0[destination as usize][0] - 1;
+        partition_data(
+            linkno,
+            aux_mutex,
+            timer,
+            data,
+            |slice, last, len| Packet::SubkernelAddDataRequest {
+                id: id,
+                destination: destination,
+                last: last,
+                length: len as u16,
+                data: *slice,
+            },
+            |reply| match reply {
+                Packet::SubkernelAddDataReply { succeeded: true } => Ok(()),
+                Packet::SubkernelAddDataReply { succeeded: false } => Err("error adding subkernel on satellite"),
+                _ => Err("adding subkernel failed, unexpected aux packet"),
+            },
+        )
+        .await
+    }
+
+    pub async fn subkernel_load(
+        aux_mutex: &Rc<Mutex<bool>>,
+        routing_table: &drtio_routing::RoutingTable,
+        timer: GlobalTimer,
+        id: u32,
+        destination: u8,
+        run: bool,
+    ) -> Result<(), &'static str> {
+        let linkno = routing_table.0[destination as usize][0] - 1;
+        let reply = aux_transact(
+            aux_mutex,
+            linkno,
+            &Packet::SubkernelLoadRunRequest {
+                id: id,
+                destination: destination,
+                run: run,
+            },
+            timer,
+        )
+        .await?;
+        match reply {
+            Packet::SubkernelLoadRunReply { succeeded: true } => return Ok(()),
+            Packet::SubkernelLoadRunReply { succeeded: false } => return Err("error on subkernel run request"),
+            _ => return Err("received unexpected aux packet during subkernel run"),
+        }
+    }
+
+    pub async fn subkernel_retrieve_exception(
+        aux_mutex: &Rc<Mutex<bool>>,
+        routing_table: &drtio_routing::RoutingTable,
+        timer: GlobalTimer,
+        destination: u8,
+    ) -> Result<Vec<u8>, &'static str> {
+        let linkno = routing_table.0[destination as usize][0] - 1;
+        let mut remote_data: Vec<u8> = Vec::new();
+        loop {
+            let reply = aux_transact(
+                aux_mutex,
+                linkno,
+                &Packet::SubkernelExceptionRequest {
+                    destination: destination,
+                },
+                timer,
+            )
+            .await?;
+            match reply {
+                Packet::SubkernelException { last, length, data } => {
+                    remote_data.extend(&data[0..length as usize]);
+                    if last {
+                        return Ok(remote_data);
+                    }
+                }
+                _ => return Err("received unexpected aux packet during subkernel exception request"),
+            }
+        }
+    }
+
+    pub async fn subkernel_send_message(
+        aux_mutex: &Rc<Mutex<bool>>,
+        routing_table: &drtio_routing::RoutingTable,
+        timer: GlobalTimer,
+        id: u32,
+        destination: u8,
+        message: &[u8],
+    ) -> Result<(), &'static str> {
+        let linkno = routing_table.0[destination as usize][0] - 1;
+        partition_data(
+            linkno,
+            aux_mutex,
+            timer,
+            message,
+            |slice, last, len| Packet::SubkernelMessage {
+                destination: destination,
+                id: id,
+                last: last,
+                length: len as u16,
+                data: *slice,
+            },
+            |reply| match reply {
+                Packet::SubkernelMessageAck { .. } => Ok(()),
+                _ => Err("sending message to subkernel failed, unexpected aux packet"),
+            },
+        )
+        .await
+    }
 }
 
 fn read_device_map(cfg: &Config) -> BTreeMap<u32, String> {

src/runtime/src/subkernel.rs

@@ -0,0 +1,321 @@
+use alloc::{collections::BTreeMap, rc::Rc, vec::Vec};
+
+use libasync::task;
+use libboard_artiq::{drtio_routing::RoutingTable, drtioaux_proto::MASTER_PAYLOAD_MAX_SIZE};
+use libboard_zynq::{time::Milliseconds, timer::GlobalTimer};
+use libcortex_a9::mutex::Mutex;
+use log::error;
+
+use crate::rtio_mgt::drtio;
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum FinishStatus {
+    Ok,
+    CommLost,
+    Exception,
+}
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum SubkernelState {
+    NotLoaded,
+    Uploaded,
+    Running,
+    Finished { status: FinishStatus },
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Error {
+    Timeout,
+    IncorrectState,
+    SubkernelNotFound,
+    CommLost,
+    DrtioError(&'static str),
+}
+
+impl From<&'static str> for Error {
+    fn from(value: &'static str) -> Error {
+        Error::DrtioError(value)
+    }
+}
+
+pub struct SubkernelFinished {
+    pub id: u32,
+    pub status: FinishStatus,
+    pub exception: Option<Vec<u8>>,
+}
+
+struct Subkernel {
+    pub destination: u8,
+    pub data: Vec<u8>,
+    pub state: SubkernelState,
+}
+
+impl Subkernel {
+    pub fn new(destination: u8, data: Vec<u8>) -> Self {
+        Subkernel {
+            destination: destination,
+            data: data,
+            state: SubkernelState::NotLoaded,
+        }
+    }
+}
+
+static SUBKERNELS: Mutex<BTreeMap<u32, Subkernel>> = Mutex::new(BTreeMap::new());
+
+pub async fn add_subkernel(id: u32, destination: u8, kernel: Vec<u8>) {
+    SUBKERNELS
+        .async_lock()
+        .await
+        .insert(id, Subkernel::new(destination, kernel));
+}
+
+pub async fn upload(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+    id: u32,
+) -> Result<(), Error> {
+    if let Some(subkernel) = SUBKERNELS.async_lock().await.get_mut(&id) {
+        drtio::subkernel_upload(
+            aux_mutex,
+            routing_table,
+            timer,
+            id,
+            subkernel.destination,
+            &subkernel.data,
+        )
+        .await?;
+        subkernel.state = SubkernelState::Uploaded;
+        Ok(())
+    } else {
+        Err(Error::SubkernelNotFound)
+    }
+}
+
+pub async fn load(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+    id: u32,
+    run: bool,
+) -> Result<(), Error> {
+    if let Some(subkernel) = SUBKERNELS.async_lock().await.get_mut(&id) {
+        if subkernel.state != SubkernelState::Uploaded {
+            return Err(Error::IncorrectState);
+        }
+        drtio::subkernel_load(aux_mutex, routing_table, timer, id, subkernel.destination, run).await?;
+        if run {
+            subkernel.state = SubkernelState::Running;
+        }
+        Ok(())
+    } else {
+        Err(Error::SubkernelNotFound)
+    }
+}
+
+pub async fn clear_subkernels() {
+    SUBKERNELS.async_lock().await.clear();
+    MESSAGE_QUEUE.async_lock().await.clear();
+    CURRENT_MESSAGES.async_lock().await.clear();
+}
+
+pub async fn subkernel_finished(id: u32, with_exception: bool) {
+    // called upon receiving DRTIO SubkernelRunDone
+    // may be None if session ends and is cleared
+    if let Some(subkernel) = SUBKERNELS.async_lock().await.get_mut(&id) {
+        subkernel.state = SubkernelState::Finished {
+            status: match with_exception {
+                true => FinishStatus::Exception,
+                false => FinishStatus::Ok,
+            },
+        }
+    }
+}
+
+pub async fn destination_changed(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+    destination: u8,
+    up: bool,
+) {
+    let mut locked_subkernels = SUBKERNELS.async_lock().await;
+    for (id, subkernel) in locked_subkernels.iter_mut() {
+        if subkernel.destination == destination {
+            if up {
+                match drtio::subkernel_upload(aux_mutex, routing_table, timer, *id, destination, &subkernel.data).await
+                {
+                    Ok(_) => subkernel.state = SubkernelState::Uploaded,
+                    Err(e) => error!("Error adding subkernel on destination {}: {}", destination, e),
+                }
+            } else {
+                subkernel.state = match subkernel.state {
+                    SubkernelState::Running => SubkernelState::Finished {
+                        status: FinishStatus::CommLost,
+                    },
+                    _ => SubkernelState::NotLoaded,
+                }
+            }
+        }
+    }
+}
+
+pub async fn get_finished_with_exception(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+) -> Result<Option<SubkernelFinished>, Error> {
+    let mut locked_subkernels = SUBKERNELS.async_lock().await;
+    for (id, subkernel) in locked_subkernels.iter_mut() {
+        match subkernel.state {
+            SubkernelState::Finished {
+                status: FinishStatus::Ok,
+            } => (),
+            SubkernelState::Finished { status } => {
+                subkernel.state = SubkernelState::Finished {
+                    status: FinishStatus::Ok,
+                };
+                return Ok(Some(SubkernelFinished {
+                    id: *id,
+                    status: status,
+                    exception: if status == FinishStatus::Exception {
+                        Some(
+                            drtio::subkernel_retrieve_exception(aux_mutex, routing_table, timer, subkernel.destination)
+                                .await?,
+                        )
+                    } else {
+                        None
+                    },
+                }));
+            }
+            _ => (),
+        }
+    }
+    Ok(None)
+}
+
+pub async fn await_finish(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+    id: u32,
+    timeout: u64,
+) -> Result<SubkernelFinished, Error> {
+    match SUBKERNELS.async_lock().await.get(&id).unwrap().state {
+        SubkernelState::Running | SubkernelState::Finished { .. } => (),
+        _ => return Err(Error::IncorrectState),
+    }
+    let max_time = timer.get_time() + Milliseconds(timeout);
+    while timer.get_time() < max_time {
+        {
+            match SUBKERNELS.async_lock().await.get(&id).unwrap().state {
+                SubkernelState::Finished { .. } => break,
+                _ => (),
+            };
+        }
+        task::r#yield().await;
+    }
+    if timer.get_time() >= max_time {
+        error!("Remote subkernel finish await timed out");
+        return Err(Error::Timeout);
+    }
+    if let Some(subkernel) = SUBKERNELS.async_lock().await.get_mut(&id) {
+        match subkernel.state {
+            SubkernelState::Finished { status } => {
+                subkernel.state = SubkernelState::Uploaded;
+                Ok(SubkernelFinished {
+                    id: id,
+                    status: status,
+                    exception: if status == FinishStatus::Exception {
+                        Some(
+                            drtio::subkernel_retrieve_exception(aux_mutex, routing_table, timer, subkernel.destination)
+                                .await?,
+                        )
+                    } else {
+                        None
+                    },
+                })
+            }
+            _ => Err(Error::IncorrectState),
+        }
+    } else {
+        Err(Error::SubkernelNotFound)
+    }
+}
+
+struct Message {
+    from_id: u32,
+    pub tag: u8,
+    pub data: Vec<u8>,
+}
+
+// FIFO queue of messages
+static MESSAGE_QUEUE: Mutex<Vec<Message>> = Mutex::new(Vec::new());
+// currently under construction message(s) (can be from multiple sources)
+static CURRENT_MESSAGES: Mutex<BTreeMap<u32, Message>> = Mutex::new(BTreeMap::new());
+
+pub async fn message_handle_incoming(id: u32, last: bool, length: usize, data: &[u8; MASTER_PAYLOAD_MAX_SIZE]) {
+    // called when receiving a message from satellite
+    if SUBKERNELS.async_lock().await.get(&id).is_none() {
+        // do not add messages for non-existing or deleted subkernels
+        return;
+    }
+    let mut current_messages = CURRENT_MESSAGES.async_lock().await;
+    match current_messages.get_mut(&id) {
+        Some(message) => message.data.extend(&data[..length]),
+        None => {
+            current_messages.insert(
+                id,
+                Message {
+                    from_id: id,
+                    tag: data[0],
+                    data: data[1..length].to_vec(),
+                },
+            );
+        }
+    };
+    if last {
+        // when done, remove from working queue
+        MESSAGE_QUEUE
+            .async_lock()
+            .await
+            .push(current_messages.remove(&id).unwrap());
+    }
+}
+
+pub async fn message_await(id: u32, timeout: u64, timer: GlobalTimer) -> Result<(u8, Vec<u8>), Error> {
+    match SUBKERNELS.async_lock().await.get(&id).unwrap().state {
+        SubkernelState::Finished {
+            status: FinishStatus::CommLost,
+        } => return Err(Error::CommLost),
+        SubkernelState::Running | SubkernelState::Finished { .. } => (),
+        _ => return Err(Error::IncorrectState),
+    }
+    let max_time = timer.get_time() + Milliseconds(timeout);
+    while timer.get_time() < max_time {
+        {
+            let mut message_queue = MESSAGE_QUEUE.async_lock().await;
+            for i in 0..message_queue.len() {
+                let msg = &message_queue[i];
+                if msg.from_id == id {
+                    let message = message_queue.remove(i);
+                    return Ok((message.tag, message.data));
+                }
+            }
+        }
+        task::r#yield().await;
+    }
+    Err(Error::Timeout)
+}
+
+pub async fn message_send<'a>(
+    aux_mutex: &Rc<Mutex<bool>>,
+    routing_table: &RoutingTable,
+    timer: GlobalTimer,
+    id: u32,
+    message: Vec<u8>,
+) -> Result<(), Error> {
+    let destination = SUBKERNELS.async_lock().await.get(&id).unwrap().destination;
+    // rpc data prepared by the kernel core already
+    Ok(drtio::subkernel_send_message(aux_mutex, routing_table, timer, id, destination, &message).await?)
+}

src/satman/src/analyzer.rs

@@ -1,6 +1,6 @@
 use core::cmp::min;
 
-use libboard_artiq::{drtioaux_proto::ANALYZER_MAX_SIZE, pl::csr};
+use libboard_artiq::{drtioaux_proto::SAT_PAYLOAD_MAX_SIZE, pl::csr};
 use libcortex_a9::cache;
 
 const BUFFER_SIZE: usize = 512 * 1024;
@@ -100,10 +100,10 @@ impl Analyzer {
         }
     }
 
-    pub fn get_data(&mut self, data_slice: &mut [u8; ANALYZER_MAX_SIZE]) -> AnalyzerSliceMeta {
+    pub fn get_data(&mut self, data_slice: &mut [u8; SAT_PAYLOAD_MAX_SIZE]) -> AnalyzerSliceMeta {
         let data = unsafe { &BUFFER.data[..] };
         let i = (self.data_pointer + self.sent_bytes) % BUFFER_SIZE;
-        let len = min(ANALYZER_MAX_SIZE, self.data_len - self.sent_bytes);
+        let len = min(SAT_PAYLOAD_MAX_SIZE, self.data_len - self.sent_bytes);
         let last = self.sent_bytes + len == self.data_len;
 
         if i + len >= BUFFER_SIZE {

src/satman/src/main.rs

@@ -27,7 +27,7 @@ use embedded_hal::blocking::delay::DelayUs;
 use libboard_artiq::io_expander;
 #[cfg(has_si5324)]
 use libboard_artiq::si5324;
-use libboard_artiq::{drtio_routing, drtioaux, drtioaux_proto::ANALYZER_MAX_SIZE, identifier_read, logger, pl::csr};
+use libboard_artiq::{drtio_routing, drtioaux, drtioaux_proto::SAT_PAYLOAD_MAX_SIZE, identifier_read, logger, pl::csr};
 #[cfg(feature = "target_kasli_soc")]
 use libboard_zynq::error_led::ErrorLED;
 use libboard_zynq::{gic, i2c::I2c, mpcore, print, println, stdio, time::Milliseconds, timer::GlobalTimer};
@@ -450,7 +450,7 @@ fn process_aux_packet(
             destination: _destination,
         } => {
             forward!(_routing_table, _destination, *_rank, _repeaters, &packet, timer);
-            let mut data_slice: [u8; ANALYZER_MAX_SIZE] = [0; ANALYZER_MAX_SIZE];
+            let mut data_slice: [u8; SAT_PAYLOAD_MAX_SIZE] = [0; SAT_PAYLOAD_MAX_SIZE];
             let meta = analyzer.get_data(&mut data_slice);
             drtioaux::send(
                 0,