libdrtioaux: do not attempt to access non-existent DRTIO gateware

artiq/firmware/libdrtioaux/Cargo.toml

@@ -2,6 +2,7 @@
 authors = ["M-Labs"]
 name = "drtioaux"
 version = "0.0.0"
+build = "build.rs"
 
 [lib]
 name = "drtioaux"

artiq/firmware/libdrtioaux/build.rs

@@ -0,0 +1,15 @@
+use std::env;
+use std::path::Path;
+use std::io::{BufRead, BufReader};
+use std::fs::File;
+
+fn main() {
+    let out_dir = env::var("BUILDINC_DIRECTORY").unwrap();
+    let cfg_path = Path::new(&out_dir).join("generated").join("rust-cfg");
+    println!("cargo:rerun-if-changed={}", cfg_path.to_str().unwrap());
+
+    let f = BufReader::new(File::open(&cfg_path).unwrap());
+    for line in f.lines() {
+        println!("cargo:rustc-cfg={}", line.unwrap());
+    }
+}

artiq/firmware/libdrtioaux/lib.rs

@@ -10,7 +10,7 @@ extern crate byteorder;
 mod proto;
 mod crc32;
 
-use std::io::{self, Cursor, Read, Write};
+use std::io::{self, Read, Write};
 use core::slice;
 use proto::*;
 
@@ -40,6 +40,11 @@ impl Packet {
     }
 }
 
+#[cfg(has_drtio)]
+pub mod hw {
+    use super::*;
+    use std::io::Cursor;
+
     const AUX_TX_BASE: usize = board::mem::DRTIO_AUX_BASE;
     const AUX_TX_SIZE: usize = board::mem::DRTIO_AUX_SIZE/2;
     const AUX_RX_BASE: usize = AUX_TX_BASE + AUX_TX_SIZE;
@@ -54,7 +59,7 @@ fn rx_has_error() -> bool {
         }
     }
 
-pub struct RxBuffer(&'static [u8]);
+    struct RxBuffer(&'static [u8]);
 
     impl Drop for RxBuffer {
         fn drop(&mut self) {
@@ -76,7 +81,7 @@ fn rx_get_buffer() -> Option<RxBuffer> {
         }
     }
 
-pub fn recv_packet() -> io::Result<Option<Packet>> {
+    pub fn recv() -> io::Result<Option<Packet>> {
         if rx_has_error() {
             return Err(io::Error::new(io::ErrorKind::Other, "gateware reported error"))
         }
@@ -122,7 +127,7 @@ fn tx_ack_buffer(length: u16) {
         }
     }
 
-pub fn send_packet(packet: &Packet) -> io::Result<()> {
+    pub fn send(packet: &Packet) -> io::Result<()> {
         let sl = tx_get_buffer();
 
         let mut writer = Cursor::new(sl);
@@ -145,3 +150,4 @@ pub fn send_packet(packet: &Packet) -> io::Result<()> {
 
         Ok(())
     }
+}

artiq/firmware/runtime/rtio_mgt.rs

@@ -113,9 +113,9 @@ mod drtio {
                 return 0
             }
             count += 1;
-            drtioaux::send_packet(&drtioaux::Packet::EchoRequest).unwrap();
+            drtioaux::hw::send(&drtioaux::Packet::EchoRequest).unwrap();
             io.sleep(100).unwrap();
-            let pr = drtioaux::recv_packet();
+            let pr = drtioaux::hw::recv();
             match pr {
                 Ok(Some(drtioaux::Packet::EchoReply)) => return count,
                 _ => {}

artiq/firmware/satman/lib.rs

@@ -14,14 +14,13 @@ extern crate drtioaux;
 
 fn process_aux_packet(p: drtioaux::Packet) {
     match p {
-        drtioaux::Packet::EchoRequest => drtioaux::send_packet(&drtioaux::Packet::EchoReply).unwrap(),
+        drtioaux::Packet::EchoRequest => drtioaux::hw::send(&drtioaux::Packet::EchoReply).unwrap(),
         _ => warn!("received unexpected aux packet {:?}", p)
     }
 }
 
-
 fn process_aux_packets() {
-    let pr = drtioaux::recv_packet();
+    let pr = drtioaux::hw::recv();
     match pr {
         Ok(None) => {},
         Ok(Some(p)) => process_aux_packet(p),