Glossary
Terms as used in this guide and the OpenSMA tree at the pinned baseline.
| Term | Definition |
|---|---|
| SMA | System Management Agent — NVIDIA’s management-controller firmware. OpenSMA is its open-source implementation for the MCXN556S. The acronym is never expanded in the OpenSMA tree itself; this expansion is per vendor documentation. |
| MCU | Microcontroller unit. Here the NXP MCXN556S, a dual-core Arm Cortex-M33 SoC. |
| core0 / core1 | The two Cortex-M33 cores of the MCXN556S. Firmware is built per core and linked together (see mcu_build.sh, PLATFORM=mcxn556-both). |
| BSP | Board Support Package — SoC/board-specific startup, clocks, and drivers. Lives under src/sys/ and src/boards/. |
| SDK | NXP MCUXpresso SDK (SDK_25_09_00_MCXN556S) providing drivers and middleware, extracted into libexec/sdk/. |
| UBS | The build system under corepdk/ubs/ (make-based) that OpenSMA drives via mcu_build.sh. |
| MCTP | Management Component Transport Protocol — the base transport a host BMC uses to reach the controller. Implemented in src/nv/mctp/ and corepdk/modules/mctp-cpp/. |
| PLDM | Platform Level Data Model — DMTF management messages carried over MCTP. src/nv/pldm/, corepdk/modules/pldm-fd/. |
| PLDM FD | PLDM Firmware Device — the PLDM firmware-update responder role. |
| SPDM | Security Protocol and Data Model — attestation/measurement and secure session. src/nv/spdm/, corepdk/modules/spdm/. |
| SSIF | SMBus System Interface — an IPMI-style interface over SMBus. src/nv/ssif/. |
| NHP | NVIDIA host protocol handler. src/nv/nhp/. |
| LSTP | The LSTP messaging/parser used for bare-metal routing. src/nv/lstp/, src/nv/lstp_bm/. |
| FRU | Field Replaceable Unit — inventory/identity data. src/nv/fru/. |
| vRoT | Virtual Root of Trust — the boot/measurement trust anchor. src/nv/vrot/. |
| Secure boot | Authentication of firmware images before execution. src/nv/secure_boot/. |
| Keyset | A named set of signing keys passed as SIGN_KEYSET= (e.g. local, local-debug, local-prod, S0) to mcu_build.sh. |
| Debug token | A signed authorization (TLV-encoded) that unlocks debug capabilities. src/nv/debugtoken/. |
| AP | Application processor — the host/GPU side the controller manages (contrast MCU firmware itself). Appears in fw_parser_ap, ap_background_copy, etc. |
| OOB | Out-of-band — management access independent of the host OS/data path. |
| ADC | Analog-to-digital converter — used by voltage/telemetry monitoring. src/nv/volt_mon/. |
| IOX | I/O expander. src/nv/iox/. |
| VCOM | Virtual COM port (serial over USB). src/nv/vcom/. |
| MODE | Build mode selector for mcu_build.sh (dev, rel, …) controlling optimization/debug. |
| PLATFORM / BOARD / PROJECT | mcu_build.sh selectors: SoC/core platform, board variant, and buildable project respectively. |
| STREAMBOOT | mcu_build.sh flag to emit multi-binary (streamed) boot images. |
| UBS Docker image | The container (libexec/ubs.dockerfile) that pins the exact build/sign toolchain. |
| GNAT | The GNU Ada compiler (gnat_arm_elf), one of OpenSMA’s three toolchains. |
| DCO | Developer Certificate of Origin — commit sign-off (git commit -s) required by CONTRIBUTING.md. |
| SPDX | Software Package Data Exchange — the license/copyright header format required on source files. |