Merge #148

148: Add a script to build for RISC-V r=labbott a=labbott

Currently, all of the scripts that run elf2tab are for the ARM boards and
also call tockloader. None of the RISC-V boards use tockloader at the moment
but still need the final tbf binary. Add a simple script to build and then
run elf2tab.

This can certainly be expanded in the future but right now I'm looking for something simple that we can keep in tree to let RISC-V be built easily against master

Co-authored-by: Laura Abbott <laura@labbott.name>

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index 651ad97..dae25d0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@
 
 language: rust
 rust:
-  - nightly-2019-11-06
+  - nightly-2020-01-16
 
 os:
   - linux

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 68c463d..1caeca5 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -45,6 +45,7 @@
 [      OK ] Dynamic dispatch
 [      OK ] Formatting
 [      OK ] Heap
+[      OK ] Drivers only instantiable once
 [      OK ] Callbacks
 [      OK ] GPIO initialization
 [      OK ] GPIO activation

codegen/src/lib.rs

diff --git a/codegen/src/lib.rs b/codegen/src/lib.rs
index 6f51b9f..9804e29 100644
--- a/codegen/src/lib.rs
+++ b/codegen/src/lib.rs
@@ -5,7 +5,6 @@
 use proc_macro::TokenStream;
 
 use quote::quote;
-use syn;
 use syn::Error;
 use syn::ItemFn;
 

examples-alloc/libtock_test.rs

diff --git a/examples-alloc/libtock_test.rs b/examples-alloc/libtock_test.rs
index d764af3..26cccb4 100644
--- a/examples-alloc/libtock_test.rs
+++ b/examples-alloc/libtock_test.rs
@@ -46,6 +46,7 @@
     test.dynamic_dispatch()?;
     test.formatting()?;
     test.heap()?;
+    test.drivers_only_instantiable_once()?;
     test.callbacks(timer).await?;
     test.gpio(gpio)?;
     Ok(())
@@ -100,6 +101,13 @@
         self.check_if_true(string == "foobar", "Heap")
     }
 
+    fn drivers_only_instantiable_once(&mut self) -> TockResult<()> {
+        self.check_if_true(
+            libtock::retrieve_drivers().is_err(),
+            "Drivers only instantiable once",
+        )
+    }
+
     async fn callbacks(&mut self, timer_context: &mut DriverContext) -> TockResult<()> {
         let mut callback_hit = false;
         let mut with_callback = timer_context.with_callback(|_, _| callback_hit = true);

run_all_checks.sh

diff --git a/run_all_checks.sh b/run_all_checks.sh
index c445608..3dde5ff 100755
--- a/run_all_checks.sh
+++ b/run_all_checks.sh
@@ -5,6 +5,6 @@
 export PLATFORM=nrf52 # The specific platform doesn't matter for tests
 
 cargo fmt --all -- --check
-cargo test --workspace
 cargo clippy --workspace --all-targets
+cargo test --workspace
 ./build_examples.sh

rust-toolchain

diff --git a/rust-toolchain b/rust-toolchain
index 22e9048..20d9cda 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2019-11-06
+nightly-2020-01-16

src/drivers.rs

diff --git a/src/drivers.rs b/src/drivers.rs
index a8e1e98..4e7eff8 100644
--- a/src/drivers.rs
+++ b/src/drivers.rs
@@ -38,9 +38,15 @@
 
 /// Retrieve [Drivers] struct. Returns struct only once.
 pub fn retrieve_drivers() -> TockResult<Drivers> {
-    match unsafe { DRIVERS_SINGLETON.take() } {
-        Some(drivers) => Ok(drivers),
-        None => Err(TockError::Other(OtherError::DriverAlreadyTaken)),
+    static mut DRIVER_TAKEN: bool = false;
+
+    unsafe {
+        if DRIVER_TAKEN {
+            Err(TockError::Other(OtherError::DriverAlreadyTaken))
+        } else {
+            DRIVER_TAKEN = true;
+            Ok(retrieve_drivers_unsafe())
+        }
     }
 }
 
@@ -73,24 +79,3 @@
     humidity_sensor: HumiditySensor,
     ninedof: NinedofDriver,
 };
-
-static mut DRIVERS_SINGLETON: Option<Drivers> = Some(DRIVERS);
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    pub fn can_be_retrieved_once() {
-        reset_drivers_singleton();
-
-        assert!(retrieve_drivers().is_ok());
-        assert!(retrieve_drivers().is_err());
-    }
-
-    fn reset_drivers_singleton() {
-        unsafe {
-            DRIVERS_SINGLETON = Some(DRIVERS);
-        };
-    }
-}

src/lang_items.rs

diff --git a/src/lang_items.rs b/src/lang_items.rs
index b8731a2..9c301eb 100644
--- a/src/lang_items.rs
+++ b/src/lang_items.rs
@@ -27,11 +27,12 @@
 use core::panic::PanicInfo;
 
 #[lang = "start"]
-extern "C" fn start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8)
+extern "C" fn start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8) -> bool
 where
     T: Termination,
 {
     main().check_result();
+    true // Need to return anything sized. Otherwise, a linker error pops up. (See https://github.com/tock/libtock-rs/issues/138)
 }
 
 #[lang = "termination"]