BFE EngineeringandClaude Opus 4.8
189f7aec38
- Dual license (LICENSE / LICENSE-MIT / LICENSE-APACHE) matching the crate manifests. - ADRs 0001-0005: kernel base (direct 5.10->6.18.46 forward-port), tiered MC/DC, standalone repo, CI runner (3rd repo-scoped runner on 0640), driver source-of-truth. - README goal 1 reconciled to the verified 6.18.46 forward-port (was stale plan44/6.6). - Drop tracked build objects (*.o now gitignored). - Capture the display (VOP dclk-pol + WIN1) and GT911 touch bring-up VERIFIED docs + capabilities-audit update from this session. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf
29 lines
1.4 KiB
Markdown
29 lines
1.4 KiB
Markdown
# ADR 0002 — Tiered MC/DC coverage policy
|
|
|
|
**Status:** Accepted (2026-08-25).
|
|
|
|
## Context
|
|
The goal "port + harden 100% of drivers to 100% MC/DC" is infeasible as literally
|
|
stated: ~97% of driver LOC is vendor blobs (the AIC8800 wifi driver alone is 88.5K
|
|
lines) that we cannot meaningfully unit-test to MC/DC on the host. Forcing MC/DC on
|
|
that code would be theatre, not assurance.
|
|
|
|
## Decision
|
|
A **two-tier** policy, measured against the Hardware Abstraction Seam:
|
|
|
|
- **Tier 1 — our own hardware-facing code → real 100% MC/DC.** `modbus_engine.c`,
|
|
`relays.c`, `warden_rga.c` (wrapper), `hpmcu.rs`, `devmem.rs`, `freshness.c`, plus
|
|
the two smallest near-mainline drivers where feasible. Enforced in CI
|
|
(`gcc-14 -fcondition-coverage` + `gcov-14 --conditions`; `cargo-llvm-cov --mcdc`
|
|
for Rust).
|
|
- **Tier 2 — ported/vendor drivers → fault-injection + branch coverage + benchmarks**
|
|
against the simulator, behind a stable seam. Explicitly NOT literal MC/DC.
|
|
|
|
## Consequences
|
|
- Matches the user's framing: "as many drivers as possible at 100% MC/DC; for the
|
|
rest, a very serious testing and benchmarking system."
|
|
- The seam is the shared object: the same thing MC/DC is measured against and the
|
|
simulator implements — the two goals reinforce, not duplicate.
|
|
- Every Tier-1 file gets a `drivers/<name>-mcdc/` host harness with an
|
|
`enforce-mcdc.sh` that fails CI below 100%.
|