Allow generic_timer example to build for Armv7-R.

It just stubs out all the timer code.

Author: thejpster

.github/workflows/build.yml

@@ -71,6 +71,8 @@ jobs:
       - name: Build
         run: |
           cargo build --target ${{ matrix.target }} -Zbuild-std=core
+          cargo build --target ${{ matrix.target }} -Zbuild-std=core --no-default-features
+          cargo build --target ${{ matrix.target }} -Zbuild-std=core --all-features
 
   # Gather all the above build jobs together for the purposes of getting an overall pass-fail
   build-all:

cortex-r-examples/src/bin/generic_timer.rs

@@ -4,7 +4,6 @@
 #![no_main]
 
 // pull in our start-up code
-use cortex_r::generic_timer::{El1PhysicalTimer, El1VirtualTimer, GenericTimer};
 use cortex_r_examples as _;
 
 use semihosting::println;
@@ -14,16 +13,20 @@ use semihosting::println;
 /// It is called by the start-up code in `cortex-m-rt`.
 #[no_mangle]
 pub extern "C" fn kmain() {
-    if let Err(e) = main() {
-        panic!("main returned {:?}", e);
-    }
+    main();
     semihosting::process::exit(0);
 }
 
-/// The main function of our Rust application.
-///
-/// Called by [`kmain`].
-fn main() -> Result<(), core::fmt::Error> {
+/// A placeholder function so that the workspace still builds
+#[cfg(not(arm_architecture = "v8-r"))]
+fn main() {
+    println!("No generic timers on this platform");
+}
+
+/// Let's test some timers!
+#[cfg(arm_architecture = "v8-r")]
+fn main() {
+    use cortex_r::generic_timer::{El1PhysicalTimer, El1VirtualTimer, GenericTimer};
     let cntfrq = cortex_r::register::Cntfrq::read().0;
     println!("cntfrq = {:.03} MHz", cntfrq as f32 / 1_000_000.0);
 
@@ -68,6 +71,4 @@ fn main() -> Result<(), core::fmt::Error> {
             timer.countdown() as i32
         );
     }
-
-    Ok(())
 }

cortex-r/src/lib.rs

@@ -5,21 +5,19 @@
 #[cfg(feature = "critical-section-single-core")]
 mod critical_section;
 
-pub mod register;
-
-pub mod interrupt;
-
 pub mod asm;
-
-#[cfg(any(test, arm_architecture = "v8-r"))]
-pub mod pmsav8;
+pub mod interrupt;
+pub mod register;
 
 #[cfg(any(test, arm_architecture = "v7-r"))]
 pub mod pmsav7;
 
-#[cfg(arm_architecture = "v8-r")]
+#[cfg(any(test, arm_architecture = "v8-r"))]
 pub mod generic_timer;
 
+#[cfg(any(test, arm_architecture = "v8-r"))]
+pub mod pmsav8;
+
 /// Generate an SVC call with the given argument.
 ///
 /// Safe to call even in Supervisor (Svc) mode, as long as your Svc handler

cortex-r/src/register/mod.rs

@@ -175,9 +175,9 @@ pub use vmpidr::Vmpidr;
 pub use vpidr::Vpidr;
 pub use vsctlr::Vsctlr;
 
-//#[cfg(arm_architecture = "v8-r")]
+#[cfg(arm_architecture = "v8-r")]
 pub mod armv8r;
-//#[cfg(arm_architecture = "v8-r")]
+#[cfg(arm_architecture = "v8-r")]
 pub use armv8r::*;
 
 pub use imp::*;