l0dable: works!

example/.cargo/config

@@ -2,7 +2,7 @@
 runner = "gdb -q -x openocd.gdb"
 rustflags = [
   "-C", "linker=arm-none-eabihf-gcc",
-  "-C", "link-args=-Tl0dable.ld -pie -fPIC",
+  "-C", "link-args=-Tl0dable.ld -n -pie -fPIC",
   "-C", "relocation-model=pic",
 ]
 

example/src/main.rs

 #![no_std]
 #![no_main]
 
+use core::fmt::Write;
 use panic_abort as _;
-use l0dable::entry;
+use l0dable::*;
 
-entry!(main);
-fn main() -> ! {
-    loop {}
+main!(main);
+fn main() {
+    writeln!(UART, "Hello from Rust\r").unwrap();
+
+    let display = Display::open();
+    for x in 0..160 {
+        display.print(160 - x, 10, "Hello Rust\0", 0xffff, 0);
+        display.update();
+    }
 }

l0dable/Cargo.toml

@@ -9,3 +9,4 @@ r0 = "0.2"
 
 [build-dependencies]
 cc = "1.0"
+bindgen = "0.51"
\ No newline at end of file

l0dable/build.rs

@@ -6,6 +6,7 @@ use std::path::PathBuf;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
+    // Linker script
     let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
     File::create(out.join("l0dable.ld"))
         .unwrap()
@@ -14,6 +15,7 @@ fn main() {
     println!("cargo:rustc-link-search={}", out.display());
     println!("cargo:rerun-if-changed=l0dable.ld");
 
+    // Link against C code
     cc::Build::new()
         .target("thumbv7em-none-eabihf")
         .compiler("arm-none-eabihf-gcc")
@@ -29,6 +31,30 @@ fn main() {
         .include("../c/lib/sdk/Libraries/CMSIS/Device/Maxim/MAX32665/Include")
         .include("../c/lib/sdk/Libraries/CMSIS/Include")
         .include("../c/lib/sdk/Libraries/MAX32665PeriphDriver/Include")
+        .file("../c/lib/sdk/Libraries/MAX32665PeriphDriver/Source/sema.c")
+        .file("../c/lib/sdk/Libraries/MAX32665PeriphDriver/Source/mxc_assert.c")
         .file("../c/l0dables/lib/hardware.c")
+        .file("../c/epicardium/api/caller.c")
+        .file("src/client.c")
         .compile("card10");
+
+    // Generate bindings to C code
+    let bindings = bindgen::Builder::default()
+        .clang_args(&[
+            "-Isrc",
+            "-I../c/epicardium",
+            "-I../c/lib/sdk/Libraries/CMSIS/Device/Maxim/MAX32665/Include",
+            "-I../c/lib/sdk/Libraries/CMSIS/Include",
+            "-I../c/lib/sdk/Libraries/MAX32665PeriphDriver/Include",
+        ])
+        .header("src/bindings.h")
+        .use_core()
+        .ctypes_prefix("super::ctypes")
+        .generate()
+        .expect("Unable to generate bindings");
+
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Couldn't write bindings!");
 }

l0dable/l0dable.ld

@@ -38,9 +38,6 @@ SECTIONS {
         KEEP(*(.text.isr_vector))
         *(.text*)
         *(.rodata*)
-
-        KEEP(*(.init))
-        KEEP(*(.fini))
     } :text
 
     .data :
@@ -75,5 +72,8 @@ SECTIONS {
         *(.interp)
         /* Dynamic linking section - nuke, we're not a .so and nothing is going to link against us. */
         *(.dynamic)
+
+        *(.debug*)
+        *(.init .fini .ARM.exidx.text.*)
     }
 }

l0dable/src/bindings.h

+#include <epicardium.h>

l0dable/src/display.rs

+use super::bindings::*;
+
+pub struct Display;
+
+impl Display {
+    pub fn open() -> Self {
+        unsafe { epic_disp_open(); }
+        Display
+    }
+
+    pub fn print(&self, x: u16, y: u16, s: &str, fg: u16, bg: u16) {
+        unsafe {
+            epic_disp_print(x, y, s.as_ptr(), fg, bg);
+        }
+    }
+
+    pub fn update(&self) {
+        unsafe {
+            epic_disp_update();
+        }
+    }
+}

l0dable/src/lib.rs

@@ -5,12 +5,12 @@ global_asm!(include_str!("crt.s"));
 
 /// Type check the user-supplied entry function.
 #[macro_export]
-macro_rules! entry {
+macro_rules! main {
     ($path:path) => {
         #[export_name = "main"]
-        pub unsafe fn __main() -> ! {
+        pub unsafe fn __main() {
             // type check the given path
-            let f: fn() -> ! = $path;
+            let f: fn() = $path;
 
             f()
         }
@@ -32,8 +32,44 @@ pub unsafe extern "C" fn Reset_Handler() -> ! {
     SystemInit();
 
     extern "Rust" {
-        fn main() -> !;
+        fn main();
     }
 
     main();
+    exit(0);
+}
+
+pub mod ctypes {
+    #![allow(non_camel_case_types)]
+
+    pub type c_int = i32;
+    pub type c_uint = u32;
+    pub type c_long = i32;
+    pub type c_ulong = u32;
+    pub type c_longlong = i64;
+    pub type c_ulonglong = u64;
+    pub type c_char = u8;
+    pub use core::ffi::c_void;
+}
+
+pub mod bindings {
+    #![allow(non_upper_case_globals)]
+    #![allow(non_camel_case_types)]
+    #![allow(non_snake_case)]
+
+    include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
+}
+use bindings::*;
+
+mod display;
+pub use display::Display;
+
+pub mod uart;
+pub const UART: uart::Uart = uart::Uart;
+
+pub fn exit(ret: i32) -> ! {
+    unsafe {
+        epic_exit(ret);
+    }
+    unreachable!()
 }

l0dable/src/uart.rs

+use core::fmt::Write;
+use super::bindings::*;
+
+pub struct Uart;
+
+impl Write for Uart {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        unsafe {
+            epic_uart_write_str(s.as_ptr(), s.len() as isize);
+        }
+        Ok(())
+    }
+}

shell.nix

@@ -16,6 +16,8 @@ stdenv.mkDerivation {
   RUST_BACKTRACE = 1;
 
   shellHook = ''
+    export LIBCLANG_PATH=${llvmPackages.libclang}/lib
+
     echo "Starting openocd…"
     ${openocd}/bin/openocd-card10 &