wifi-densepose/firmware/esp32-csi-node/components/ruv_temporal

ruv_temporal — ESP32-S3 on-device temporal head

ESP-IDF component implementing ADR-095 (#513). The Rust staticlib at src/lib.rs wraps ruvllm_sparse_attention (vendored at vendor/ruvector/crates/ruvllm_sparse_attention) and exposes a narrow C ABI declared in include/ruv_temporal.h.

Status

Phase	Scope	State
4 — Scaffold	Cargo.toml, src/{lib.rs,window.rs}, include/ruv_temporal.h, CMakeLists.txt, .cargo/config.toml	Done. Source compiles host-side syntax check; not yet cross-compiled to xtensa.
5 — Cross-compile	cargo +esp build --release --target xtensa-esp32s3-none-elf produces libruv_temporal.a.	Blocked — see below.
6 — Wire from edge_processing.c	FreeRTOS task on Core 1, queue from adaptive_controller fast loop, push() in fast tick, classify() at 1 Hz, emit 0xC5110007 packet.	Not started.
7 — COM8 validation	Flash 8MB build with CONFIG_CSI_TEMPORAL_HEAD_ENABLED=y, soak ≥5 min, check no Tmr Svc / task_wdt overflow.	Not started.

Phase 5 blocker — esp toolchain rust-src bug

The system esp toolchain at C:\Users\ruv\.rustup\toolchains\esp has no precompiled core for xtensa-esp32s3-none-elf. It requires -Z build-std=core,alloc, but the bundled rust-src snapshot (esp channel, nightly 2025-09-16) hits two known bugs when build-std compiles core:

1. library/portable-simd/crates/core_simd/src/simd/ptr/mut_ptr.rs — Copy trait and size_of not in scope, ~16,000 errors.
2. library/core itself — "cannot resolve a prelude import", "attributes starting with rustc are reserved", concat! macro not found.

These are upstream Rust nightly snapshot regressions, not anything this component is doing wrong. The fix is to refresh the esp toolchain to a newer nightly:

C:/Users/ruv/.cargo/bin/espup.exe install
# (re-source export-esp.ps1 / export-esp.sh after install)

espup install pulls the latest pinned esp Rust + LLVM. It is a ~1.5 GB download and ~5-10 min install. That step lands in the next loop iteration of #513 implementation work.

Build (once Phase 5 unblocks)

From this directory:

cargo +esp build --release --target xtensa-esp32s3-none-elf

Output: target/xtensa-esp32s3-none-elf/release/libruv_temporal.a.

ESP-IDF's idf.py build will pick this up via CMakeLists.txt — add_custom_command runs the cargo build before idf_component_register consumes the static library.

C ABI summary

esp_err_t ruv_temporal_init(const uint8_t *weights, size_t wlen,
                            uint32_t input_dim, uint32_t window_len,
                            uint32_t n_classes,
                            ruv_temporal_ctx_t **out_ctx);
esp_err_t ruv_temporal_push(ruv_temporal_ctx_t *ctx, const float *frame);
esp_err_t ruv_temporal_classify(ruv_temporal_ctx_t *ctx,
                                float *logits, uint32_t n_classes);
void      ruv_temporal_destroy(ruv_temporal_ctx_t *ctx);
esp_err_t ruv_temporal_kernel_self_test(void);

Threading: caller is responsible. Per ADR-095 §3.3, the firmware will spawn a single dedicated FreeRTOS task that owns the context and serialises all calls — push() and classify() are not internally synchronised.