Licensing and Distribution

Relevant source files

• Cargo.toml

This document covers the licensing strategy and distribution mechanisms for the riscv_goldfish crate. It explains the triple licensing scheme, distribution channels, package metadata configuration, and legal implications for different integration scenarios. For information about target platform configuration and cross-compilation setup, see Target Platforms and Cross-Compilation.

Licensing Strategy

The riscv_goldfish crate employs a triple licensing approach that maximizes compatibility across different legal frameworks and use cases. The license specification uses an OR-based structure allowing users to choose the most appropriate license for their specific requirements.

Triple License Configuration

The crate is licensed under three alternative licenses as defined in Cargo.toml(L7) :

GPL-3.0-or-later OR Apache-2.0 OR MulanPSL-2.0

License Selection Framework

flowchart TD
subgraph use_cases["Use Case Compatibility"]
    COPYLEFT["Copyleft Projects"]
    PERMISSIVE["Permissive Projects"]
    CHINESE["Chinese Legal Framework"]
end
subgraph license_options["Available License Options"]
    GPL["GPL-3.0-or-later"]
    APACHE["Apache-2.0"]
    MULAN["MulanPSL-2.0"]
end
subgraph riscv_goldfish_crate["riscv_goldfish Crate"]
    LICENSE_FIELD["license = GPL-3.0-or-later OR Apache-2.0 OR MulanPSL-2.0"]
end

APACHE --> PERMISSIVE
CHINESE --> MULAN
COPYLEFT --> GPL
GPL --> COPYLEFT
LICENSE_FIELD --> APACHE
LICENSE_FIELD --> GPL
LICENSE_FIELD --> MULAN
MULAN --> CHINESE
PERMISSIVE --> APACHE

Sources: Cargo.toml(L7) 

License Characteristics

Sources: Cargo.toml(L7) 

Distribution Channels

The crate is distributed through multiple channels to ensure accessibility and discoverability across different platforms and communities.

Distribution Infrastructure

flowchart TD
subgraph discovery["Discovery Metadata"]
    KEYWORDS["keywords = arceos, riscv, rtc"]
    CATEGORIES["categories = os, hardware-support, no-std"]
end
subgraph documentation["Documentation"]
    DOCS_RS["docs.rs/riscv_goldfish"]
    DOC_URL["documentation = docs.rs/riscv_goldfish"]
end
subgraph package_registry["Package Registry"]
    CRATES_IO["crates.io"]
    CARGO_TOML["Cargo.toml metadata"]
end
subgraph source_control["Source Control"]
    REPO_URL["repository = github.com/arceos-org/riscv_goldfish"]
    HOMEPAGE["homepage = github.com/arceos-org/arceos"]
end

CARGO_TOML --> CRATES_IO
CATEGORIES --> CRATES_IO
CRATES_IO --> DOCS_RS
DOC_URL --> DOCS_RS
HOMEPAGE --> CRATES_IO
KEYWORDS --> CRATES_IO
REPO_URL --> CRATES_IO

Sources: Cargo.toml(L8 - L12) 

Package Metadata Configuration

The distribution strategy leverages comprehensive metadata to maximize discoverability and provide clear project context:

Core Metadata Fields

• Package Name: riscv_goldfish - clearly identifies the target platform and hardware component
• Version: 0.1.1 - semantic versioning with patch-level updates
• Authors: Keyang Hu <keyang.hu@qq.com> - primary maintainer contact
• Description: System Real Time Clock (RTC) Drivers for riscv based on goldfish

Discovery and Classification

The crate uses targeted keywords and categories to ensure proper classification in the Rust ecosystem:

Keywords Cargo.toml(L11) :

• arceos - Associates with the ArceOS operating system project
• riscv - Identifies the target processor architecture
• rtc - Specifies the hardware component type

Categories Cargo.toml(L12) :

• os - Operating system components
• hardware-support - Hardware abstraction and drivers
• no-std - Embedded and bare-metal compatibility

Sources: Cargo.toml(L2 - L12) 

Legal Implications and Use Cases

The triple licensing structure addresses different legal requirements and integration scenarios that may arise when incorporating the RTC driver into various projects.

Integration Scenarios

ArceOS Integration

The crate is designed for integration with the ArceOS operating system project, as indicated by the homepage reference Cargo.toml(L8)  The licensing allows ArceOS to choose the most appropriate license based on their distribution strategy.

Commercial Embedded Systems

The Apache-2.0 option enables integration into proprietary embedded systems and commercial products without source disclosure requirements, making it suitable for industrial IoT and embedded applications.

Open Source Projects

The GPL-3.0-or-later option ensures compatibility with other GPL-licensed operating system components while providing future license version flexibility.

Chinese Market Compliance

The MulanPSL-2.0 option addresses specific legal framework requirements for distribution within Chinese jurisdictions, supporting domestic technology adoption.

License Compatibility Matrix

flowchart TD
subgraph license_selection["License Selection"]
    CHOOSE_GPL["Choose GPL-3.0-or-later"]
    CHOOSE_APACHE["Choose Apache-2.0"]
    CHOOSE_MULAN["Choose MulanPSL-2.0"]
end
subgraph downstream_projects["Downstream Project Types"]
    GPL_PROJECT["GPL-licensed OS Components"]
    COMMERCIAL["Commercial Embedded Systems"]
    PERMISSIVE_PROJECT["MIT/BSD Licensed Projects"]
    CHINESE_PROJECT["Chinese Domestic Projects"]
end

CHINESE_PROJECT --> CHOOSE_MULAN
CHOOSE_APACHE --> COMMERCIAL
CHOOSE_APACHE --> PERMISSIVE_PROJECT
CHOOSE_GPL --> GPL_PROJECT
CHOOSE_MULAN --> CHINESE_PROJECT
COMMERCIAL --> CHOOSE_APACHE
GPL_PROJECT --> CHOOSE_GPL
PERMISSIVE_PROJECT --> CHOOSE_APACHE

Sources: Cargo.toml(L7 - L8) 

Distribution Workflow

The package distribution leverages Cargo's ecosystem integration to provide automated publishing and documentation generation:

1. Source Publication: Code is maintained in the GitHub repository specified in Cargo.toml(L9) 
2. Package Registry: Automated publishing to crates.io using metadata from Cargo.toml(L1 - L12) 
3. Documentation Generation: Automatic docs.rs publication linked from Cargo.toml(L10) 
4. Discoverability: Search optimization through keywords and categories in Cargo.toml(L11 - L12) 

The triple licensing approach ensures that regardless of the downstream project's legal requirements, there is a compatible license option available, maximizing the driver's utility across different integration scenarios while maintaining compliance with various legal frameworks.

Sources: Cargo.toml(L7 - L12)