Prepare the Compilation Environment. Using a local Ubuntu system, the officially supported compilation environment is `Ubuntu Jammy 22.04.x amd64` only!
If you are using other Linux distributions, we strongly recommend that you use the Docker environment to compile to reduce the probability of compilation errors.
### Ubuntu 22.04 LTSに必要なツール
The following describes the compilation methods in the two environments.
*Note: The first compilation will automatically download the required toolchain, which is approximately 840MB in size. Once downloaded, it will be automatically extracted to the `host-tools` directory in the SDK directory. For subsequent compilations, if the `host-tools` directory is detected, the download will not be performed again*.
### 手動コンパイル
### <2>. Step-by-step Compilation
手動コンパイルをしたい場合は以下のコマンドを順に実行します。
If you wish to perform step-by-step compilation, you can enter the following commands sequentially:
Location of the generated image: `install/soc_cv1800b_milkv_duo_sd/milkv-duo.img`.
## 2. Compiled using Docker
Docker support is required on hosts running Linux systems. For how to use Docker, please refer to the [official documentation](https://docs.docker.com/) or other tutorials.
We put the SDK source code on the Linux host system and call the Docker image environment provided by Milk-V to compile it.
-`duodocker` The name of the running Docker must be consistent with the name set in the previous step.
-`"*"` In quotes is the shell command to be run in the Docker image.
-`cd /home/work` Switch to the /home/work directory. Since this directory has been bound to the host's code directory during runtime, the /home/work directory in Docker is the source code directory of the SDK.
-`cat /etc/issue` Displays the version number of the image used by Docker. It is currently Ubuntu 22.04.3 LTS and is used for debugging.
After successful compilation, you can see the generated SD card burning image `milkv-duo-*-*.img` in the `out` directory.
### <2>. Compile step by step using Docker
Step-by-step compilation requires logging into Docker to operate. Use the command `docker ps -a` to view and record the ID number of the container, such as 8edea33c2239.
After compilation is completed, you can use the `exit` command to exit the Docker environment:
```
root@8edea33c2239:/home/work# exit
```
The generated firmware can also be seen in the host code directory.
### Stop Docker
After compilation is completed, if the above Docker running environment is no longer needed, you can stop it first and then delete it:
```
docker stop 8edea33c2239
docker rm 8edea33c2239
```
## Other compilation considerations
If you want to try to compile this SDK in an environment other than the above two environments, the following are things you may need to pay attention to, for reference only.
### cmake version
Note：`cmake` minimum version requirement is `3.16.5`.
Check the version of `cmake` in the system:
```bash
cmake --version
```
For example, the version of `cmake` installed using apt in the `Ubuntu 20.04` is:
```
cmake version 3.16.3
```
The minimum requirement of this SDK is not met. Manual installation of the latest version `3.27.6` is needed:
sudo sh cmake-3.27.6-linux-x86_64.sh --skip-license--prefix=/usr/local/
```
When manually installed, `cmake` is located in `/usr/local/bin`. To check its version, use the command `cmake --version`, which should display:
```
cmake version 3.27.6
```
### Compiling with Windows Linux Subsystem (WSL)
If you wish to perform the compilation with WSL, there's an small issue building the image.
The $PATH, due Windows interoperability, has Windows environment variables which include some spaces between the paths.
To solve this problem you need to change the `/etc/wsl.conf` file and add the following lines:
```
[interop]
appendWindowsPath = false
```
After that, you need to reboot the WSL with `wsl.exe --reboot`. Then you able to run the `./build_milkv.sh` script or the `build_all` line in the step-by-step compilation method.
To rollback this change in `/etc/wsl.conf` file set `appendWindowsPath` as true. To reboot the WSL, can you use the Windows PowerShell command `wsl.exe --shutdown` then `wsl.exe`, after that the Windows environment variables become avaliable again in $PATH.
