Overview

Relevant source files

• Cargo.toml
• README.md

This document provides a comprehensive overview of the x86_rtc crate, a specialized Rust library that provides low-level hardware access to the Real Time Clock (RTC) on x86_64 systems via CMOS interface. The crate is designed for operating system kernels, embedded systems, and bare-metal applications that require direct hardware clock access without relying on operating system services.

For detailed API documentation and usage patterns, see RTC Driver API. For information about the underlying hardware protocols and register access, see CMOS Hardware Interface. For build configuration and dependency management, see Crate Definition and Metadata.

System Architecture

The x86_rtc crate operates as a hardware abstraction layer between application code and the x86_64 CMOS hardware that maintains system time.

High-Level System Architecture

flowchart TD
subgraph subGraph3["Physical Hardware"]
    CMOS["CMOS Chip"]
    RTC_HW["Real Time Clock"]
    BATTERY["Battery Backup"]
end
subgraph subGraph2["Hardware Abstraction"]
    X86_64["x86_64 crate"]
    PORTS["I/O Port Access"]
    CMD_PORT["CMOS_COMMAND_PORT"]
    DATA_PORT["CMOS_DATA_PORT"]
end
subgraph subGraph1["x86_rtc Crate"]
    API["Rtc struct"]
    TIMESTAMP["get_unix_timestamp()"]
    SETTER["set_unix_timestamp()"]
    CONVERSION["BCD/Binary Conversion"]
end
subgraph subGraph0["Application Layer"]
    APP["Application Code"]
    OS["Operating Systems"]
    EMBEDDED["Embedded Systems"]
end

API --> SETTER
API --> TIMESTAMP
APP --> API
CMD_PORT --> CMOS
CMOS --> BATTERY
CMOS --> RTC_HW
CONVERSION --> X86_64
DATA_PORT --> CMOS
EMBEDDED --> API
OS --> API
PORTS --> CMD_PORT
PORTS --> DATA_PORT
SETTER --> CONVERSION
TIMESTAMP --> CONVERSION

Sources: Cargo.toml(L1 - L22)  README.md(L1 - L13) 

Code Entity Mapping

This diagram maps the crate's public interface to its internal implementation and hardware dependencies, showing the relationship between user-facing APIs and underlying code constructs.

Code Entity Architecture

Sources: Cargo.toml(L14 - L18)  README.md(L9 - L12) 

Key Characteristics

Sources: Cargo.toml(L1 - L13) 

Integration Context

The x86_rtc crate is part of the broader ArceOS ecosystem, as indicated by its homepage and keywords. It serves as a specialized hardware driver component that can be integrated into larger operating system or embedded system projects.

Ecosystem Integration

flowchart TD
subgraph subGraph3["Use Cases"]
    SYSTEM_TIME["System Time Management"]
    BOOT_TIME["Boot Time Initialization"]
    TIMESTAMP["Event Timestamping"]
end
subgraph subGraph2["Target Platforms"]
    LINUX["x86_64-unknown-linux-gnu"]
    BARE_METAL["x86_64-unknown-none"]
    EMBEDDED["Embedded x86_64"]
end
subgraph subGraph1["x86_rtc Crate"]
    X86_RTC["x86_rtc v0.1.1"]
    RTC_API["RTC Hardware Interface"]
end
subgraph subGraph0["ArceOS Ecosystem"]
    ARCEOS["ArceOS Operating System"]
    DRIVERS["Hardware Drivers"]
    KERNEL["Kernel Components"]
end

ARCEOS --> DRIVERS
BARE_METAL --> BOOT_TIME
DRIVERS --> X86_RTC
EMBEDDED --> TIMESTAMP
KERNEL --> X86_RTC
LINUX --> SYSTEM_TIME
RTC_API --> BARE_METAL
RTC_API --> EMBEDDED
RTC_API --> LINUX
X86_RTC --> RTC_API

Sources: Cargo.toml(L8 - L12)  Cargo.toml(L11 - L12) 

The crate provides essential time-keeping functionality for systems that need direct hardware access to the RTC, particularly in contexts where higher-level operating system time services are unavailable or insufficient. Its design prioritizes minimal dependencies, hardware-specific optimization, and compatibility with both hosted and bare-metal environments.