no_std, regc tool, fix enum resolution, more safety

[rcgoodfellow]

• Adds no_std support.
• Adds a regc tool for checking/compiling/viewing RSF specs.
• Support for descriptors: registers that are not managed directly by the RPI but indirectly through things like DMA descriptor rings.
• Fixes type resolution issues when enums are referenced across modules.
• Via no_std support, infallible get/set/mask field operations bitset#4 there are now no unwraps needed on field get/set methods.
• Eliminate expect/unwrap from generated code and add a test to make sure it does not find it's way back in.

[Copilot]

Pull Request Overview

This PR adds no_std support to the Rust RPI library, introduces a regc tool for working with RSF specs, and eliminates unwrap/expect calls from generated code for improved safety. The changes also fix enum resolution issues across modules and add support for descriptor registers.

• Converts the library to no_std for embedded compatibility
• Replaces fallible operations in generated code with proper error handling
• Restructures the codebase into a workspace with separate rust_rpi crate

Reviewed Changes

Copilot reviewed 14 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
rust_rpi/src/lib.rs	Adds no_std support and moves OutOfRange error definition inline
rust_rpi/Cargo.toml	Creates new rust_rpi crate package definition
lib/tests/codegen.rs	Updates test paths and adds checks to prevent unwrap/expect in generated code
lib/test_data/nic_rpi.rs	Shows generated code changes with proper error handling instead of unwraps
lib/src/rust_codegen.rs	Major refactoring to eliminate unwraps and improve enum handling
lib/src/parser.rs	Improves error handling and updates test paths
lib/src/model.rs	Refactors module path handling and improves type resolution
lib/src/lib.rs	Removes unused modules from library exports
lib/src/common.rs	Adds utility method for Component trait
lib/src/ast.rs	Minor debug trait addition and test path updates
lib/Cargo.toml	Creates lib crate package definition with workspace dependencies
examples/nic.rsf	Updates enum width from 2 to 3 bits
Readme.md	Documents new regc tool and primitive types
Cargo.toml	Converts to workspace structure

Comments suppressed due to low confidence (3)

rust_rpi/Cargo.toml:4

• Rust edition "2024" does not exist. The available editions are "2015", "2018", and "2021". This should be changed to "2021" which is the latest stable edition.

edition = "2024"

lib/Cargo.toml:4

• Rust edition "2024" does not exist. The available editions are "2015", "2018", and "2021". This should be changed to "2021" which is the latest stable edition.

edition = "2024"

Cargo.toml:8

• Rust edition "2024" does not exist. The available editions are "2015", "2018", and "2021". This should be changed to "2021" which is the latest stable edition.

edition = "2024"