Initial commit

firmware/.cargo/config.toml

@@ -0,0 +1,6 @@
+[target.riscv32i-unknown-none-elf]
+rustflags = ["-Clink-arg=-Tlink.ld"]
+[build]
+target = "riscv32i-unknown-none-elf"
+[unstable]
+build-std = ["core"]

firmware/.gitignore

@@ -0,0 +1 @@
+/target

firmware/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "firmware"
+version = "0.1.0"

firmware/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "firmware"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

firmware/link.ld

@@ -0,0 +1,35 @@
+ENTRY(__entry);
+
+SECTIONS {
+    . = 0x1000;
+
+    .text : {
+        *(.text.entry)
+        *(.text*)
+    }
+
+    . = ALIGN(4);
+
+    .rodata : {
+        *(.rodata*)
+        . = ALIGN(4);
+    }
+
+    . = 0x20000;
+
+    .vectors : {
+        *(.text.vectors)
+    }
+
+    . = 0x20000000;
+
+    .data : {
+        *(.data*)
+    }
+
+    . = ALIGN(16);
+
+    .bss : {
+        *(.bss*)
+    }
+}

firmware/src/entry.S

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+.global __entry
+
+.pushsection .text.entry
+.option push
+.option norvc
+__entry:
+    la sp, stack_top
+    jal {firmware_main}
+
+.option pop
+.popsection // .text.entry
+
+.pushsection .text.vectors
+__vector:
+    j .
+.popsection // .text.vectors
+
+.pushsection .bss
+stack_bottom:
+    .skip 2048
+stack_top:
+.popsection // .bss

firmware/src/main.rs

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+#![allow(unsafe_op_in_unsafe_fn)]
+#![no_std]
+#![no_main]
+
+use core::{arch::global_asm, fmt, panic::PanicInfo};
+
+#[panic_handler]
+fn panic_handler(_pi: &PanicInfo) -> ! {
+    loop {}
+}
+
+struct D;
+
+const DEBUG_BASE: usize = 0x1000_0000;
+
+impl fmt::Write for D {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        let ptr: *mut u32 = core::ptr::with_exposed_provenance_mut(DEBUG_BASE);
+        for byte in s.bytes() {
+            unsafe { ptr.write_volatile(byte as u32) };
+        }
+        Ok(())
+    }
+}
+
+unsafe extern "C" fn firmware_main() -> ! {
+    use fmt::Write;
+
+    let mut d = D;
+    for i in 0..10 {
+        write!(d, "Hello {i}").ok();
+        write!(d, "\n").ok();
+    }
+
+    loop {
+        // TODO pause/system/fence instruction not implemented
+        // core::hint::spin_loop();
+        core::arch::asm!("nop");
+    }
+}
+
+global_asm!(include_str!("entry.S"), firmware_main = sym firmware_main);