# Embedded Working Group Meeting 2024-05-14

* [Coordination Repository]
* Meetings: Tuesday 8pm Europe/Berlin time
* [Join the Chat]
* Today's date: 2024-05-14
* [Nominated issues](https://github.com/search?q=org%3Arust-embedded+label%3Anominated+is%3Aopen&type=Issues)
* [Discussion topic](https://github.com/rust-embedded/wg/discussions/747)
* [IRC logs]

[Coordination Repository]: https://github.com/rust-embedded/wg
[Join the Chat]: https://matrix.to/#/#rust-embedded:matrix.org
[IRC logs]: https://libera.irclog.whitequark.org/rust-embedded/2024-05-14

## Attendance

Write your GH username or Matrix handle here!

* adamgreig
* dirbaio
* jamesmunns
* Adam Hott
* hdoordt
* sirhcel
* nastevens
* alevy
* newAM
* therealprof
* bartmassey
* jannic (late)

## Agenda

* Announcements
* svd2rust 0.33.3 released
* tracking issue to discuss postcard 2.0 https://github.com/jamesmunns/postcard/issues/128
* RustNL recap
* https://hackmd.io/p6bQ0OzqTj-R9ra11LvP8A
* Roadmap for WG work
* Keep working on supported targets and foundational crates like embedded-hal
* Improve documentation, tutorials, examples, libraries to ensure many more
people can become embedded Rust developers
* Improve visibility and discoverability of our work, especially considering
specific target audiences
* Coordinate with vendors
* Ensure we have a good experience for hobbyists coming from platforms such as Arduino,
including GUI-only installation experience
* Working group meetings and structure
* We'd like to remain part of the Rust project and on the whole they'd like something like that too
* There's a proposed "Rust Application Organisation" (name TBC) to collect Rust _users_, which we might also become involved in
* We should be involved on the Rust Zulip more to improve communication with Project members
* Proposal for a new sub-team who are responsible for directly interacting with the Rust Project and have a weekly meeting on Zulip (maybe not every week, depending on what topics come up)
* Use of volatilecell and PAC singletons
* We need to stop using vcell, move svd2rust and cortex-m to chiptool-style pointers in structs which generate offsets for register access
* Still want to split c-m into PAC/HAL layer (and perhaps -asm)
* Concluded to propose removing owned singletons from svd2rust, make this a HAL concern instead
* Proposal for new MMIO functionality in Rust itself, e.g. mmio_read/mmio_write on ptr,
and in the interim we could emulate this in cortex-m with inline assembly
* Also add an mmio_fence function
* Rust + Bluetooth
* Work in progress on TrouBLE with some tasks assigned
* PAC/Arch/Runtime crate interactions
* Agreed on previous plan to make cortex-m-pac-interface with interrupt trait so that PACs don't have to depend on arch or runtime crates
* Looked at how Risc-V is split (-pac, -peripheral, -, -rt)
* Discussed interrupt macro syntax options to be able to separate it from the PACs,
current conclusion is something like `#[interrupt(pac::Interrupt::UART0)] fn foo() {}`
* Binary data structure representations
* Documentation
* Discussed a plan (see hackmd link above) for discovery book:
* Split and archive the old f3disco and mb1 books
* Pros
* Prevents creating new issues for the old books
* Cons
* Is there actually a need for maintaining the older books?
* What about just keeping them (along with their issues) "archived" (issues closed) in the same repo?
* In combination with hosting the older books as-is (see below)
* Update current book for full mb2
* Discussed having a simple BSP that's part of the book (or its own crate) to keep the first examples easy, moving to direct HAL use later in the book
* Might be able to obtain funding to pay students to help with some chapters
* Need better CI
* Also want to create a new FAQ page with common questions
* We should check where else users are asking questions, such as Discourse
* HAL reference examples
* Probe-rs
* Lots of things to work on and roadmap items planned, see doc for details
* Discussed embedded pain points with Rust project
* Future of static mut
* We discussed the `grounded` crate
* Rust wants to more or less deprecate the use of static mut, it already generates a warning and will
be forbidden in the 2024 edition
* `grounded` offers some well-documented wrappers for many common use cases
* We decided to keep developing/documenting grounded as-is for the immediate time being, with a plan to move it into the wg libs team soon, and potentially see some structs move into Rust itself later
* Binary code size discussion
* Various code size pain points discussed
* RFC opened to add a new flag to std allowing size optimisations
* Embedded HAL
* Documentation
* Discovery book
* Issues [#568](https://github.com/rust-embedded/discovery/issues/568) & [#567](https://github.com/rust-embedded/discovery/issues/567)
* Permission to resources team for @hdoordt and @bartmassey?
* https://github.com/rust-embedded/wg/pull/756
* Keeping the previous books hosted?
* Pros
* Keeping these variants still easily accessible
* Catching unknown links under https://docs.rust-embedded.org/discovery/, tell about the new book and still guide to the older variants
* Being friendly and not letting aspiring Rust embedded devs with already some cognitive load on their journey just hit a 404 wall
* Cons
* Some work for embedded WG
* Referencing known-good documentation for architectures not covered in the book like std-sync and std-async (on ESP32)
* See for example https://github.com/rust-embedded/discovery/pull/559
* Providing some guidance in contrast somewhat somewhat overwhelming _Awesome Embedded Rust_ for beginners
* Actions-rs deprecated for GitHub Actions
* Issue [#754](https://github.com/rust-embedded/wg/issues/754)
* Do we need separate issues per-repo, or "just do it"?
* Preferences for rust-toolchain versus just rustup?
* Anything (checks, dependabot, etc) that should be included/excluded from all repos?
* Decided nastevens will go through repos currently on actions-rs and do simple migration
* Then use what's learned from this migration to propose CI template if it makes sense
* risc-v CSR access unsafe or not? https://github.com/rust-embedded/riscv/issues/209

## Last Week's Minutes

* Announcements
* embedded-hal-bus 0.2 released with AtomicDevice
* Target docs for thumb targets PR underway: https://github.com/rust-lang/rust/pull/124404
* @thejpster stepping down from wg and leadership council
* next week's meeting is skipped, resuming the week after (on 14th may)
* Embedded HAL
* AtomicDevice use of portable_atomic means build fails on armv6 https://github.com/rust-embedded/embedded-hal/issues/598
* add atomic-device feature, enable AtomicDevice if feature is enabled or cfg(target_has_atomic..), add atomic-critical-section and atomic-unsafe-assume-single-core (or portable-atomic-...?) which proxy to p-a and also enable atomic-device, document this, release as 0.3
* Tooling docs update: https://github.com/CodingInGreen/tooling
* what to add?
* Maintenance of STM32 Discovery Book?
* Is our most complete book
* Does not seem to be in widespread use anymore
* Board has changed version
* Two books is a lot
* Conclusion: don't worry about the stm32 book, mark it as more clearly archived/read-only/deprecated