OpenBIC Overview

OpenBIC is an open-source Baseboard Management Controller (BMC) firmware built on Zephyr RTOS, demonstrating enterprise-grade embedded system design.

What is OpenBIC?

OpenBIC provides out-of-band management capabilities for server platforms:

flowchart TB
    subgraph Server
        CPU[Host CPU]
        MEM[Memory]
        Storage[Storage]
        PSU[Power Supply]
    end

    subgraph OpenBIC["OpenBIC BMC"]
        MGMT[Management Controller]
        SENSOR[Sensor Monitoring]
        POWER[Power Control]
        COMM[Communication]
    end

    subgraph External
        Admin[Admin Console]
        Cloud[Cloud Management]
    end

    MGMT --> CPU
    SENSOR --> MEM & PSU & CPU
    POWER --> PSU
    COMM --> Admin & Cloud

    CPU -.->|IPMI/PLDM| MGMT

Key Features

Feature	Description
Sensor Monitoring	Temperature, voltage, power sensors
Power Management	Host power control, sequencing
Event Logging	SEL (System Event Log)
Remote Management	IPMI, PLDM protocols
Firmware Update	In-band and out-of-band updates

Project Structure

openbic/
├── common/                 # Shared code across platforms
│   ├── dev/               # Device drivers
│   ├── lib/               # Common libraries
│   ├── service/           # Services (IPMI, PLDM, etc.)
│   └── shell/             # Shell commands
├── meta-facebook/         # Platform-specific configs
│   └── boards/            # Board configurations
├── fix_patch/             # Zephyr patches
└── scripts/               # Build and utility scripts

Why Zephyr?

OpenBIC chose Zephyr for several reasons:

Real-time Capabilities - Predictable response times for hardware monitoring
Small Footprint - Fits in constrained BMC hardware
Rich Driver Support - I2C, SPI, GPIO for sensor access
Active Community - Continuous improvements and security updates
Vendor Neutral - No licensing restrictions

Hardware Platform

Typical OpenBIC deployment:

flowchart LR
    subgraph BMC["BMC SoC"]
        ARM[ARM Cortex-M]
        I2C[I2C Controllers]
        SPI[SPI Controllers]
        UART[UART]
        ETH[Ethernet MAC]
    end

    subgraph Sensors
        TEMP[Temp Sensors]
        VOLT[Voltage Monitors]
        FAN[Fan Controllers]
        PWR[Power Monitors]
    end

    subgraph Host
        CPU[Host CPU]
        ME[Management Engine]
    end

    I2C --> Sensors
    SPI --> Flash[Boot Flash]
    UART --> Host
    ETH --> Network[Management Network]

Getting Started

Prerequisites

# Install Zephyr SDK
# Install west

# Clone repository
git clone https://github.com/facebook/openbic.git
cd openbic

Build

# Initialize west workspace
west init -l .
west update

# Build for specific platform
west build -b ast1030_evb meta-facebook/yv35-cl/

Flash

west flash

Configuration System

OpenBIC uses Kconfig extensively:

# Platform selection
CONFIG_META_FACEBOOK=y
CONFIG_PLAT_CC=y

# Features
CONFIG_IPMI=y
CONFIG_PLDM=y
CONFIG_SENSOR_MONITOR=y

# Hardware
CONFIG_I2C=y
CONFIG_GPIO=y
CONFIG_SPI=y

Development Workflow

flowchart LR
    Dev[Development] --> Build[Build]
    Build --> Test[Test on EVB]
    Test --> Review[Code Review]
    Review --> CI[CI Testing]
    CI --> Merge[Merge]
    Merge --> Release[Release]

Learning Outcomes

From studying OpenBIC, you’ll learn:

Modular Architecture - How to structure large Zephyr projects
Protocol Implementation - IPMI/PLDM message handling
Sensor Framework - Scalable sensor management
Platform Abstraction - Supporting multiple hardware variants
Production Practices - CI/CD, testing, release management

Next Steps

Dive into the OpenBIC Architecture to understand its internal design.