Embedded Rust on RISC-V Part 1

First and foremost, this course don't cover toolchain installation This course starts with building blocks needed to bootstrap RISC-V processor into rust and finishes by booting Hifive1-Rev B board into Embedded Rust. Regarding the code management, there are many ways to manage code in rust; this course adopts Cargo workspace.

Section 1: Introduction

• Introduction

• Preamble

• What is covered & what isn't

• Resources & expectation

Section 2: Cargo Workspace

• Create Cargo workspace

• Create a binary crate to build an executable

• Create library crate to keep reusable code

• Create Cargo.toml to manage dependencies

  
  

Then this course jumps into the Embedded-rust & Cargo settings.

Section 3: Embedded-rust and Cargo settings for RISC-V Embedded Rust target

• What are attributes in Rust?

• What is Embedded Rust?

• Provide custom panic handler and entry function

• The difference between Cargo toml file vs config file

• How to configure Cargo Workspace to build for RISC-V instead of host?

• How to pass additional flags to Rust compiler?

• How to pass custom linker file for target (Hifive1-RevB board)?

NOTE: This course don't cover how to write linker file. However, the linker file is shared as downloadable resource.

Section 4: Commands to dissect ELF and RUSTFLAGS

• Commands to extract information from ELF

• RUSTFLAGS in rust to tweak compiler behaviour

• How to add custom linker file with RUSTFLAGS

With workspace & code management taken care, next is to add RISC-V boot up code in RISC-V assembly.

Section 5: Simple RISC-V boot code   (Binary Crate)

• How to add a assembly (.S) file?

• Disable interrupts at boot time

• Set the stack pointer to valid location

• How to jump from RISC-V assembly to Embedded Rust entry function?

• Build an executable with boot code in RISC-V assembly with entry & panic handler in Rust

Section 6: UART Driver in Rust  (Library Crate)

• Structs and Impls in Rust

• Uart driver functions

• Build an executable with boot code in RISC-V asm and UART driver in Rust.

• Connect to Hifive1-RevB board with OpenOCD & GDB server

• Load the executable into Hifive1-RevB

• Read messages from serial out with serial tools

NOTE: This section uses a OpenOCD script but don't discuss about the script content. However, the script is shared as downloadable resource. 

Update on Dec 5, 2024:  Attached boot.S file on Section #5