firmware: use aux ping to determine when DRTIO satellite is ready

artiq/firmware/Cargo.lock

@@ -52,6 +52,16 @@ name = "cslice"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "drtioaux"
+version = "0.0.0"
+dependencies = [
+ "board 0.0.0",
+ "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "std_artiq 0.0.0",
+]
+
 [[package]]
 name = "fringe"
 version = "1.1.0"
@@ -125,6 +135,7 @@ dependencies = [
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.0 (git+https://github.com/rust-lang-nursery/compiler-builtins?rev=631b568)",
  "cslice 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "drtioaux 0.0.0",
  "fringe 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "logger_artiq 0.0.0",
@@ -145,6 +156,7 @@ dependencies = [
  "board 0.0.0",
  "build_artiq 0.0.0",
  "compiler_builtins 0.1.0 (git+https://github.com/rust-lang-nursery/compiler-builtins)",
+ "drtioaux 0.0.0",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "logger_artiq 0.0.0",
  "std_artiq 0.0.0",

artiq/firmware/runtime/Cargo.toml

@@ -19,6 +19,7 @@ logger_artiq = { path = "../liblogger_artiq" }
 cslice = { version = "0.3" }
 log = { version = "0.3", default-features = false, features = ["max_level_debug"] }
 board = { path = "../libboard", features = ["uart_console"] }
+drtioaux = { path = "../libdrtioaux" }
 fringe = { version = "= 1.1.0", default-features = false, features = ["alloc"] }
 byteorder = { version = "1.0", default-features = false }
 

artiq/firmware/runtime/lib.rs

@@ -14,6 +14,8 @@ extern crate fringe;
 extern crate smoltcp;
 #[macro_use]
 extern crate board;
+#[cfg(has_drtio)]
+extern crate drtioaux;
 
 use std::boxed::Box;
 use smoltcp::wire::{EthernetAddress, IpAddress};

artiq/firmware/runtime/rtio_mgt.rs

@@ -39,12 +39,27 @@ pub mod crg {
 #[cfg(has_drtio)]
 mod drtio {
     use super::*;
+    use drtioaux;
 
     pub fn startup(io: &Io) {
         io.spawn(4096, link_thread);
         io.spawn(4096, error_thread);
     }
 
+    static mut LINK_RUNNING: bool = false;
+
+    fn link_set_running(running: bool) {
+        unsafe {
+            LINK_RUNNING = running
+        }
+    }
+
+    fn link_is_running() -> bool {
+        unsafe {
+            LINK_RUNNING
+        }
+    }
+
     fn link_is_up() -> bool {
         unsafe {
             csr::drtio::link_status_read() == 1
@@ -80,7 +95,7 @@ mod drtio {
     }
 
     pub fn init() {
-        if link_is_up() {
+        if link_is_running() {
             unsafe {
                 csr::drtio::reset_write(1);
                 while csr::drtio::o_wait_read() == 1 {}
@@ -91,20 +106,40 @@ mod drtio {
         }
     }
 
+    fn ping_remote(io: &Io) -> u32 {
+        let mut count = 0;
+        loop {
+            if !link_is_up() {
+                return 0
+            }
+            count += 1;
+            drtioaux::send_packet(&drtioaux::Packet::EchoRequest).unwrap();
+            io.sleep(100).unwrap();
+            let pr = drtioaux::recv_packet();
+            match pr {
+                Ok(Some(drtioaux::Packet::EchoReply)) => return count,
+                _ => {}
+            }
+        }
+    }
+
     pub fn link_thread(io: Io) {
         loop {
             io.until(link_is_up).unwrap();
-            info!("link RX is up");
+            info!("link RX is up, pinging");
 
-            io.sleep(10000).unwrap();
-            info!("wait for remote side done");
-
-            init();  // clear all FIFOs first
-            reset_phy();
-            sync_tsc();
-            info!("link initialization completed");
+            let ping_count = ping_remote(&io);
+            if ping_count > 0 {
+                info!("remote replied after {} packets", ping_count);
+                link_set_running(true);
+                init();  // clear all FIFOs first
+                reset_phy();
+                sync_tsc();
+                info!("link initialization completed");
+            }
 
             io.until(|| !link_is_up()).unwrap();
+            link_set_running(false);
             info!("link is down");
         }
     }

artiq/firmware/satman/Cargo.toml

@@ -17,6 +17,7 @@ alloc_artiq = { path = "../liballoc_artiq" }
 std_artiq = { path = "../libstd_artiq", features = ["alloc"] }
 logger_artiq = { path = "../liblogger_artiq" }
 board = { path = "../libboard", features = ["uart_console"] }
+drtioaux = { path = "../libdrtioaux" }
 log = { version = "0.3", default-features = false }
 
 [dependencies.compiler_builtins]

artiq/firmware/satman/lib.rs

@@ -9,6 +9,26 @@ extern crate std_artiq as std;
 extern crate log;
 extern crate logger_artiq;
 extern crate board;
+extern crate drtioaux;
+
+
+fn process_aux_packet(p: drtioaux::Packet) {
+    match p {
+        drtioaux::Packet::EchoRequest => drtioaux::send_packet(&drtioaux::Packet::EchoReply).unwrap(),
+        _ => warn!("received unexpected aux packet {:?}", p)
+    }
+}
+
+
+fn process_aux_packets() {
+    let pr = drtioaux::recv_packet();
+    match pr {
+        Ok(None) => {},
+        Ok(Some(p)) => process_aux_packet(p),
+        Err(e) => warn!("aux packet error ({})", e)
+    }
+}
+
 
 #[cfg(rtio_frequency = "62.5")]
 const SI5324_SETTINGS: board::si5324::FrequencySettings
@@ -55,7 +75,9 @@ fn startup() {
         while !drtio_link_is_up() {}
         info!("link is up, switching to recovered clock");
         board::si5324::select_ext_input(true).expect("failed to switch clocks");
-        while drtio_link_is_up() {}
+        while drtio_link_is_up() {
+            process_aux_packets();
+        }
         info!("link is down, switching to local crystal clock");
         board::si5324::select_ext_input(false).expect("failed to switch clocks");
     }