bup: it works!

beginner/apps/Cargo.toml

@@ -18,7 +18,7 @@ debug = 1
 debug-assertions = true # !
 incremental = false
 lto = "fat"
-opt-level = 'z' # !
+opt-level = 0
 overflow-checks = false
 
 [profile.release]

tools/Cargo.lock

@@ -169,6 +169,7 @@ dependencies = [
  "probe-rs",
  "probe-rs-rtt",
  "rustc-demangle",
+ "thiserror",
  "xmas-elf",
 ]
 

tools/dk-run/Cargo.toml

@@ -15,3 +15,4 @@ probe-rs = "0.6.2"
 probe-rs-rtt = "0.1.0"
 rustc-demangle = "0.1.16"
 xmas-elf = "0.7.0"
+thiserror = "1.0.11"

tools/dk-run/src/main.rs

@@ -13,6 +13,7 @@ use std::{
     process,
     rc::Rc,
 };
+use core::fmt::Error;
 
 use anyhow::{anyhow, bail};
 use arrayref::array_ref;
@@ -192,17 +193,42 @@ fn notmain() -> Result<i32, anyhow::Error> {
     // run
 
     let core = Rc::new(core);
-    let mut rtt = Rtt::attach_region(
-        core.clone(),
-        &sess,
-        &ScanRegion::Exact(rtt_addr.ok_or_else(|| anyhow!("RTT control block not available"))?),
-    )?;
+    let mut num_retries = 5;
+
+    let mut rtt: Result<Rtt, probe_rs_rtt::Error>;
+
+    loop {
+        // TODO how do i best to this without allocating two rtts
+        rtt = Rtt::attach_region(
+            core.clone(),
+            &sess,
+            &ScanRegion::Exact(rtt_addr.ok_or_else(|| anyhow!("RTT control block not available"))?), // todo only do this once?
+        );
+
+        // todo clean up control flow
+        if rtt.is_ok() {
+            log::info!("successfully attached rtt");
+            break;
+        }
+
+        num_retries -= 1;
+        if num_retries == 0 {
+            // todo return last err instead
+            break;
+        }
+        log::info!("Rtt::attach_region failed. retrying.");
+    }
+
+    log::info!("go rtt");
 
     let channel = rtt
+        .unwrap()
         .up_channels()
         .take(0)
         .ok_or_else(|| anyhow!("RTT up channel 0 not found"))?;
 
+    log::info!("chan");
+
     static CONTINUE: AtomicBool = AtomicBool::new(true);
 
     ctrlc::set_handler(|| {