Bump in-tree mctp-rs to dymk/mctp-rs @ 1b8b7f5

[dymk]

Bump in-tree mctp-rs to dymk/mctp-rs @ 1b8b7f5

Bumps the in-tree mctp-rs/ source from 3d941ba (current v0.2.0 baseline imported in #823) to 1b8b7f5 (the head of dymk/mctp-rs main). This brings the in-tree copy to parity with the dymk fork's main, after which dymk/mctp-rs will be archived.

The high-level MctpPacketContext::deserialize_packet/serialize_packet API signatures are identical between 3d941ba and 1b8b7f5 (only internal MctpMedium::deserialize/serialize cursor types changed). All 4 in-tree consumers (uart-service, espi-service, embedded-service, plus macro re-exports) use the high-level MctpPacketContext API, so zero consumer source changes were required. Consumer test counts are unchanged at 128.

What's picked up

• BufferEncoding trait + EncodingDecoder/EncodingEncoder cursor wrappers (src/buffer_encoding.rs, NEW) — stateless cross-medium encoding abstraction; threads through MctpMedium::deserialize/serialize internals
• MctpSerialMedium DSP0253 byte-stuffed serial framer with CRC-16/X-25 FCS (src/medium/serial.rs, NEW; gated behind opt-in serial feature)
• wire_size_of chunk-sizing fix in src/serialize.rs (correctly accounts for encoding overhead during packet chunking)
• SerialEncoding byte-stuffing implementation (in medium/serial.rs)

Source lineage

Source: dymk/mctp-rs main @ 1b8b7f5
Bumps from: 3d941ba (v0.2.0 baseline imported in #823)

Carry-forwards from #823

These edits are preserved across the bump:

• Dropped cargo-husky from [dev-dependencies] (workspace-root build script incompatibility; the source at 1b8b7f5 still has cargo-husky declared but the in-tree copy must drop it)
• Did NOT re-introduce per-crate mctp-rs/rustfmt.toml (workspace style governs; source at 1b8b7f5 has a rustfmt.toml for nightly rustfmt, but the workspace uses stable rustfmt with max_width = 120)
• [package.metadata.cargo-machete] ignored block updated to add "crc" (now an opt-in optional dep behind the serial feature; cargo-machete would otherwise false-positive at default features)
• Source reformatted under the workspace style (separate fmt-only commit; no semantic change)

Test results

Suite	Pre-bump	Post-bump	Delta
Workspace total passed	178	185	+7
mctp-rs unit tests	~47	54	+7
mctp-rs doctests	3	3	0
Consumer crates (sum)	128	128	0

cargo test --workspace exits 0. New mctp-rs tests come from buffer_encoding.rs cursor unit tests at default features. The 41+ medium/serial.rs golden-fixture tests live behind opt-in --features serial and are exercised by the hack-clippy cargo-hack feature-powerset job in check.yml.

Cargo.lock churn

• Workspace Cargo.lock regenerated via cargo build --workspace. mctp-rs entry remains source-less (path-pinned).
• NEW transitive entries in Cargo.lock: crc 3.4.0 and crc-catalog 2.4.0 (both gated behind opt-in serial; neither is reachable from cargo build --workspace at default features).
• cargo tree -p mctp-rs is byte-identical pre/post at default features (verified via diff).
• Example lockfiles regenerated via cd examples/<name> && cargo update -p mctp-rs: examples/std, examples/rt685s-evk, examples/pico-de-gallo updated. examples/rt633 does not depend on mctp-rs and is untouched.

cargo-vet

cargo vet --locked reports: Vetting Succeeded (220 fully audited, 1 partially audited, 15 exempted).

Added one new exemption for crc 3.4.0 as safe-to-deploy in supply-chain/config.toml (alphabetically interleaved via cargo vet fmt). crc-catalog 2.4.0 did not require a new exemption — already audited via imports.lock (OpenDevicePartnership-imported audit by Jerry Xie, Microsoft).

CI matrix coverage (hack-clippy)

check.yml's hack-clippy job runs cargo hack --feature-powerset --mutually-exclusive-features=log,defmt,defmt-timestamp-uptime workspace-wide across {stable,beta} × {x86_64-unknown-linux-gnu, thumbv8m.main-none-eabihf}. Since mctp-rs is a workspace member, this matrix automatically exercises the new serial feature (16 feature combinations total).

[Copilot]

Pull request overview

Updates the in-tree mctp-rs workspace member to a newer upstream snapshot, adding an internal buffer-encoding abstraction so media can transparently apply byte-stuffing, and introducing an opt-in DSP0253 serial medium (CRC/FCS + framing) while keeping the high-level MctpPacketContext::{deserialize_packet,serialize_packet} API surface stable for existing consumers.

Changes:

• Add BufferEncoding + EncodingDecoder/EncodingEncoder cursors and thread them through MctpMedium (de)serialization.
• Fix packet chunk sizing in serialization to account for encoding overhead (stuffing) when computing per-packet body size.
• Add a new serial feature implementing DSP0253 serial framing + CRC-16/X-25 (with new crc dependency + vet exemption).

Reviewed changes

Copilot reviewed 11 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
supply-chain/config.toml	Adds a cargo-vet exemption for crc 3.4.0.
mctp-rs/Cargo.toml	Introduces optional crc dep and serial feature; updates cargo-machete ignored list.
mctp-rs/src/buffer_encoding.rs	New encoding abstraction and encoder/decoder cursors (+ unit tests).
mctp-rs/src/deserialize.rs	Transport-header parsing updated to read via encoding-aware decoder.
mctp-rs/src/lib.rs	Wires in new module and re-exports encoding types; re-exports serial medium behind feature.
mctp-rs/src/mctp_packet_context.rs	Decodes packet bodies via EncodingDecoder to support stuffed media.
mctp-rs/src/medium/mod.rs	Extends MctpMedium trait with Encoding and updates serialize/deserialize signatures.
mctp-rs/src/medium/smbus_espi.rs	Adapts SMBus/eSPI medium to encoding-aware cursors (passthrough encoding).
mctp-rs/src/medium/serial.rs	New DSP0253 serial medium implementation + fixtures and tests (feature-gated).
mctp-rs/src/serialize.rs	Adjusts chunk sizing to account for encoding wire overhead; writes through encoder.
mctp-rs/src/test_util.rs	Updates test medium to the new encoding-aware MctpMedium signature.
Cargo.lock	Adds/updates lock entries for new optional crc dependency.
examples/std/Cargo.lock	Regenerated example lockfile (git pin churn).
examples/rt685s-evk/Cargo.lock	Regenerated example lockfile (git pin churn).
examples/pico-de-gallo/Cargo.lock	Regenerated example lockfile (git pin churn).

[williampMSFT]