fw: do most of command interface

firmware/Cargo.lock

@@ -50,6 +50,12 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "crc-any"
+version = "2.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "774646b687f63643eb0f4bf13dc263cb581c8c9e57973b6ddf78bda3994d88df"
+
 [[package]]
 name = "critical-section"
 version = "1.1.1"
@@ -102,6 +108,7 @@ dependencies = [
 name = "fw"
 version = "0.1.0"
 dependencies = [
+ "crc-any",
  "defmt",
  "embedded-hal",
  "panic-halt",

firmware/Cargo.toml

@@ -11,11 +11,12 @@ riscv = "0.10.1"
 panic-halt = "0.2.0"
 embedded-hal = "0.2.7"
 defmt = { version = "0.3.4", features = ["encoding-raw"] }
+crc-any = { version = "2.4", default-features = false }
 
 [dependencies.smoltcp]
 version = "0.9.1"
 default-features = false
-features = ["medium-ethernet", "proto-ipv4", "socket-icmp", "defmt"]
+features = ["medium-ethernet", "proto-ipv4", "socket-tcp", "socket-icmp", "defmt"]
 
 [profile.release]
 debug = true

firmware/src/command_interface.rs

@@ -0,0 +1,97 @@
+use smoltcp::socket::tcp::{Socket, State};
+
+use crate::proto::{
+    serialize_response_error, serialize_response_value, PacketParser, ResponsePacket, Settings, ErrorCodes
+};
+
+struct CommandInterface {
+    parser: PacketParser,
+}
+
+impl CommandInterface {
+    pub fn new() -> Self {
+        Self {
+            parser: PacketParser::new(),
+        }
+    }
+
+    /// Run the command interface
+    pub fn run(&mut self, sock: &mut Socket) {
+        // Note that we don't attempt to check status of the connection. All of
+        // the smoltcp functions handle the error cases gracefully. Recv
+        // provides a buffer of length 0 when there is nothing to receive, so we
+        // are good there. We just reset on any smoltcp errors.
+
+        // TODO should put packet parsing behind a fn with the smoltcp result, then on smoltcp error
+        // we reconfigure here instead of calling it 4 times
+
+        // Try and parse a packet
+        let res = sock.recv(|rx_buf| {
+            let (res, processed_bytes) = self.parser.try_parse(rx_buf);
+
+            (processed_bytes, res.ok())
+        });
+
+        // Check for socket errors
+        let packet = match res {
+            Ok(Some(packet)) => packet,
+            // No packet to process
+            Ok(None) => return,
+            // Any socket error means we just want to drop the connection and re-connect
+            Err(_) => {
+                Self::reestablish_socket(sock);
+                return;
+            }
+        };
+
+        // Check that setting is valid
+        let setting = match Settings::try_from(packet.setting) {
+            Ok(v) => v,
+            Err(()) => {
+                // Write out an error packet
+                let result = sock.send(|tx_buf| {
+                    if tx_buf.len() < 8 {
+                        return (0, ());
+                    }
+
+                    let response = serialize_response_error(packet.setting, ErrorCodes::InvalidSetting);
+                    &tx_buf[0..8].copy_from_slice(&response);
+                    return (8, ());
+                });
+
+                if let Err(_) = result {
+                    // TX error, close socket and reconnect
+                    Self::reestablish_socket(sock);
+                }
+
+                return;
+            }
+        };
+
+        // TODO validate setting values
+
+        // TODO handle actually changing/getting settings in all the ways
+        // For temp testing, return values sent
+        match sock.send(|tx_buf| {
+            if tx_buf.len() < 8 {
+                // Since this is a low-BW configuration socket, we assume we have space, and drop
+                // the response otherwise. If this is an issue, may re-think this and queue commands but
+                // for now this is fine.
+                return (0, ());
+            }
+            let response = serialize_response_value(setting, packet.value);
+            &tx_buf[0..8].copy_from_slice(&response);
+            return (8, ());
+        }) {
+            Ok(()) => (),
+            Err(_) => {
+                Self::reestablish_socket(sock);
+            }
+        };
+    }
+
+    fn reestablish_socket(sock: &mut Socket) {
+        sock.abort();
+        sock.listen(2000);
+    }
+}

firmware/src/main.rs

@@ -29,6 +29,7 @@ mod uart;
 mod litex_uart;
 mod logging;
 mod proto;
+mod command_interface;
 
 const MAC: [u8; 6] = [0xA0, 0xBB, 0xCC, 0xDD, 0xEE, 0xF0];