c4595d2504
1, this RomFS's codebase is Nuttx romfs, then it is compatible with
Linux RomFS and you can create such a file system using the tool genromfs.
2, there are two major changes against with the original Nuttx romfs:
1), it is memory-based: all contents of the fs are stored in the
memory in the very first stage of "mount".
2), this version of romfs is altered to be compatible with our new
version of VFS to take advantage of vnode cache and path cache.
close: #I3S0CP
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|---|---|---|
| .gitee | ||
| apps | ||
| arch | ||
| bsd | ||
| compat/posix | ||
| drivers/char | ||
| figures | ||
| fs | ||
| kernel | ||
| lib | ||
| net | ||
| platform | ||
| security | ||
| shell | ||
| syscall | ||
| testsuites | ||
| tools | ||
| .gitignore | ||
| BUILD.gn | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| README_zh-HK.md | ||
| README_zh.md | ||
| build.sh | ||
| config.mk | ||
| kernel_test.sources | ||
README.md
LiteOS Cortex-A
Introduction
The OpenHarmony LiteOS Cortex-A is a new-generation kernel developed based on the Huawei LiteOS kernel. Huawei LiteOS is a lightweight operating system OS built for the Internet of Things IoT field. With the rapid development of the IoT industry, OpenHarmony LiteOS Cortex-A brings small-sized, low-power, and high-performance experience and builds a unified and open ecosystem for developers. In addition, it provides rich kernel mechanisms, more comprehensive Portable Operating System Interface POSIX, and a unified driver framework, Hardware Driver Foundation HDF, which offers unified access for device developers and friendly development experience for application developers. Figure 1 shows the architecture of the OpenHarmony LiteOS Cortex-A kernel.
Figure 1 Architecture of the OpenHarmony LiteOS Cortex-A kernel
Directory Structure
/kernel/liteos_a
├── apps # User-space init and shell application programs
├── arch # System architecture, such as ARM
│ └── arm # Code for ARM architecture
├── bsd # Code of the driver and adaptation layer module related to the FreeBSD, such as the USB module
├── compat # Kernel API compatibility
│ └── posix # POSIX APIs
├── drivers # Kernel drivers
│ └── char # Character device
│ ├── mem # Driver for accessing physical input/output (I/O) devices
│ ├── quickstart # APIs for quick start of the system
│ ├── random # Driver for random number generators
│ └── video # Framework of the framebuffer driver
├── fs # File system module, which mainly derives from the NuttX open-source project
│ ├── fat # FAT file system
│ ├── jffs2 # JFFS2 file system
│ ├── include # Header files exposed externally
│ ├── nfs # NFS file system
│ ├── proc # proc file system
│ ├── ramfs # RAMFS file system
│ └── vfs # VFS layer
├── kernel # Kernel modules including the process, memory, and IPC modules
│ ├── base # Basic kernel modules including the scheduling and memory modules
│ ├── common # Common components used by the kernel
│ ├── extended # Extended kernel modules including the dynamic loading, vDSO, and LiteIPC modules
│ ├── include # Header files exposed externally
│ └── user # Init process loading
├── lib # Kernel library
├── net # Network module, which mainly derives from the lwIP open-source project
├── platform # Code for supporting different systems on a chip (SOCs), such as Hi3516D V300
│ ├── hw # Logic code related to clocks and interrupts
│ ├── include # Header files exposed externally
│ └── uart # Logic code related to the serial port
├── platform # Code for supporting different systems on a chip (SOCs), such as Hi3516D V300
├── security # Code related to security features, including process permission management and virtual ID mapping management
├── syscall # System calling
└── tools # Building tools as well as related configuration and code
Constraints
- Programming languages: C and C++
- Applicable development boards: Hi3518E V300 and Hi3516D V300
- Hi3518E V300 uses the JFFS2 file system by default, and Hi3516D V300 uses the FAT file system by default.
Usage
OpenHarmony LiteOS Cortex-A supports the Hi3518E V300 and Hi3516D V300. You can develop and run your applications based on both development boards.
Preparations
You need to set up the compilation environment on Linux.
- For Hi3518E V300, see Setting Up the Hi3518 Development Environment.
- For Hi3516D V300, see Setting Up the Hi3516 Development Environment.
Source Code Acquisition
Download and decompress a set of source code on a Linux server to acquire the source code. For more acquisition methods, see Source Code Acquisition.
Compilation and Building
For details about how to develop the first application, see:
Repositories Involved
kernel_liteos_a