Source

This document introduces the development environment, download, and compilation methods for the SDK source code.

Development Environment

Hardware Configuration

Recommended configuration:

• CPU: 12th Gen Intel(R) Core(TM) i5 or above
• Memory: 16GB or above
• Disk: SSD, 256GB or above

Operating System

Recommended Ubuntu 20.04 or newer LTS version, other Linux distributions have not been tested.

Install Dependencies

Ubuntu 16.04 and 18.04:

sudo apt-get install git build-essential cpio unzip rsync file bc wget python3 libncurses5-dev libssl-dev dosfstools mtools u-boot-tools flex bison python3-pip
sudo pip3 install pyyaml

Ubuntu 20.04 or higher:

sudo apt-get install git build-essential cpio unzip rsync file bc wget python3 python-is-python3 libncurses5-dev libssl-dev dosfstools mtools u-boot-tools flex bison python3-pip
sudo pip3 install pyyaml

Download

Preparation

Bianbu Linux code is hosted on Gitee and consists of several repositories managed by repo. Before downloading, you need to:

1. Before downloading, refer to this document to set up SSH Keys.

2. Use repo --version to confirm the version and the repo source. The repo version must be >= 2.41, and the source should be the Tsinghua mirror for downloading the complete SDK; otherwise, the download process may encounter issues.

repo --version
repo version v2.48
       (from https://mirrors.tuna.tsinghua.edu.cn/git/git-repo)
       (tracking refs/heads/stable)
       (Mon, 7 Oct 2024 18:44:19 +0000)
repo launcher version 2.50
       (from /usr/bin/repo)
       (currently at 2.48)
repo User-Agent git-repo/2.48 (Linux) git/2.25.1 Python/3.8.10
git 2.25.1
git User-Agent git/2.25.1 (Linux) git-repo/2.48
Python 3.8.10 (default, Nov  7 2024, 13:10:47)
[GCC 9.4.0]
OS Linux 5.4.0-196-generic (#216-Ubuntu SMP Thu Aug 29 13:26:53 UTC 2024)
CPU x86_64 (x86_64)
Bug reports: https://issues.gerritcodereview.com/issues/new?component=1370071

If the version requirement is not met or the source is not Tsinghua, refer to Git Repo Mirror Usage Help for installation.

Version Branches

The main branch of the manifests repository defines the manifest.xml files for different versions. The xml files specify the paths and branches of each repository.

Version	manifest.xml	Branch
v1.0	bl-v1.0.y.xml	bl-v1.0.y
v2.0	bl-v2.0.y.xml	bl-v2.0.y
v2.1	k1-bl-v2.1.y.xml	k1-bl-v2.1.y

Download Code

For example, to download the code for version 2.1:

mkdir ~/bianbu-linux-2.1
cd ~/bianbu-linux-2.1
repo init -u git@gitee.com:bianbu-linux/manifests.git -b main -m k1-bl-v2.1.y.xml
repo sync
repo start k1-bl-v2.1.y --all

To download other branches, specify a different manifest.xml using the -m option.

After downloading the source code, It is recommended to download the third-party software packages required by buildroot in advance and distribute them within the team to avoid network congestion on the main server.

wget -c -r -nv -np -nH -R "index.html*" http://archive.spacemit.com/buildroot/dl

Directory structure

├── bsp-src               # Stores linux kernel、uboot、opensbi source
│   ├── linux-6.6
│   ├── opensbi
│   └── uboot-2022.10
├── buildroot             # buildroot main directory
├── buildroot-ext         # Custom extensions, including board, configs, package, patches subdirectories
├── Makefile              # Top-level Makefile
├── package-src           # Directory for locally expanded application or library source code
│   ├── ai-support
│   ├── drm-test
│   ├── img-gpu-powervr
│   ├── k1x-cam
│   ├── k1x-jpu
│   ├── k1x-vpu-firmware
│   ├── k1x-vpu-test
│   ├── mesa3d
│   ├── mpp
│   └── v2d-test
└── scripts               # Scripts used for compilation

Cross Compilation

Bianbu Linux 2.0 First Complete Compilation

For the first compilation, it is recommended to use make envconfig for a complete build.

If you have modified buildroot-ext/configs/spacemit_<solution>_defconfig, use make envconfig to compile.

In other cases, use make to compile.

cd ~/bianbu-linux
make envconfig
Available configs in buildroot-ext/configs/:
  1. spacemit_k1_defconfig
  2. spacemit_k1_upstream_defconfig
  3. spacemit_k1_minimal_defconfig
  4. spacemit_k1_plt_defconfig
  5. spacemit_k1_rt_defconfig
  6. spacemit_k1_v2_defconfig


your choice (1-6): 

To compile Bianbu Linux 2.0 version, enter 6 and press Enter to start compiling.

The compilation process may require downloading some third-party software packages, and the time required depends on the network environment. If you have downloaded the third-party software packages required by buildroot in advance, the recommended hardware configuration compilation time is about 1 hour.

After the compilation is complete, you will see:

Images successfully packed into /home/username/bianbu-linux/output/k1_v2/images/bianbu-linux-k1_v2.zip


Generating sdcard.img...................................
INFO: cmd: "mkdir -p "/home/username/bianbu-linux/output/k1_v2/build/genimage.tmp"" (stderr):
INFO: cmd: "rm -rf "/home/username/bianbu-linux/output/k1_v2/build/genimage.tmp"/*" (stderr):
INFO: cmd: "mkdir -p "/home/username/bianbu-linux/output/k1_v2/images"" (stderr):
INFO: hdimage(sdcard.img): adding partition 'bootinfo' from 'factory/bootinfo_sd.bin' ...
INFO: hdimage(sdcard.img): adding partition 'fsbl' (in MBR) from 'factory/FSBL.bin' ...
INFO: hdimage(sdcard.img): adding partition 'env' (in MBR) from 'env.bin' ...
INFO: hdimage(sdcard.img): adding partition 'opensbi' (in MBR) from 'opensbi.itb' ...
INFO: hdimage(sdcard.img): adding partition 'uboot' (in MBR) from 'u-boot.itb' ...
INFO: hdimage(sdcard.img): adding partition 'bootfs' (in MBR) from 'bootfs.img' ...
INFO: hdimage(sdcard.img): adding partition 'rootfs' (in MBR) from 'rootfs.ext4' ...
INFO: hdimage(sdcard.img): adding partition '[MBR]' ...
INFO: hdimage(sdcard.img): adding partition '[GPT header]' ...
INFO: hdimage(sdcard.img): adding partition '[GPT array]' ...
INFO: hdimage(sdcard.img): adding partition '[GPT backup]' ...
INFO: hdimage(sdcard.img): writing GPT
INFO: hdimage(sdcard.img): writing protective MBR
INFO: hdimage(sdcard.img): writing MBR
Successfully generated at /home/username/work/bianbu-linux/output/k1_v2/images/bianbu-linux-k1_v2-sdcard.img

Among them, bianbu-linux-k1_v2.zip is suitable for Titan Flasher, or you can unzip it and use fastboot to flash; bianbu-linux-k1_v2-sdcard.img is the sdcard firmware, which can be written to the sdcard using the dd command or balenaEtcher after unzipping.

Titan Flasher User Guide: Flashing Tool User Guide

The default username for the firmware is root, and the password is bianbu.

Bianbu PREEMPT_RT Linux First Complete Compilation

For the first compilation, it is recommended to use make envconfig for a complete build.

If you have modified buildroot-ext/configs/spacemit_<solution>_defconfig, use make envconfig to compile.

In other cases, use make to compile.

cd ~/bianbu-linux
make envconfig
Available configs in buildroot-ext/configs/:
  1. spacemit_k1_defconfig
  2. spacemit_k1_upstream_defconfig
  3. spacemit_k1_minimal_defconfig
  4. spacemit_k1_plt_defconfig
  5. spacemit_k1_rt_defconfig
  6. spacemit_k1_v2_defconfig


your choice (1-6): 

To compile Bianbu PREEMPT_RT Linux 2.0 version, enter 5 ,then press Enter to start compiling, the compile process will apply PREEMPT_RT patch

buildroot-ext/configs//spacemit_k1_rt_defconfig
Patching linux with PREEMPT_RT patch
Applying rt-linux-support.patch using patch:
...

After the compilation is complete, you will see:

Images successfully packed into /home/username/bianbu-linux/output/k1_rt/images/bianbu-linux-k1_rt.zip
...
Successfully generated at /home/username/work/bianbu-linux/output/k1_rt/images/bianbu-linux-k1_rt-sdcard.img

Configuration

buildroot

Config:

make menuconfig

Save the configuration, which is saved by default to buildroot-ext/configs/spacemit_k1_v2_defconfig:

make savedefconfig

linux

Config:

make linux-menuconfig

Save the configuration, which is saved by default to bsp-src/linux-6.6/arch/riscv/configs/k1_defconfig:

make linux-update-defconfig

u-boot

Config:

make uboot-menuconfig

Save the configuration, which is saved by default to bsp-src/uboot-2022.10/configs/k1_defconfig:

make uboot-update-defconfig

Recompile Completely

If you have already compiled completely using make envconfig, you can directly use make to recompile completely.

Compile Specific Packages

buildroot supports compiling specific packages. You can view the guide with make help.

Common commands:

• Delete the build directory of <pkg>: make <pkg>-dirclean
• Compile <pkg>: make <pkg>

To compile the kernel:

make linux-rebuild

To compile u-boot:

make uboot-rebuild

After compiling the specified package, you can download it to the device for verification or compile it into the firmware:

make

Standalone Compilation

The cross-compiler download URL is http://archive.spacemit.com/toolchain/, and it can be used after decompression.

Such as spacemit-toolchain-linux-glibc-x86_64-v1.0.0.tar.xz:

sudo tar -Jxf /path/to/spacemit-toolchain-linux-glibc-x86_64-v1.0.0.tar.xz -C /opt

Set environment variables:

export PATH=/opt/spacemit-toolchain-linux-glibc-x86_64-v0.3.3/bin:$PATH
export CROSS_COMPILE=riscv64-unknown-linux-gnu-
export ARCH=riscv

Compile opensbi

cd bsp-src/opensbi
make -j$(nproc) PLATFORM_DEFCONFIG=k1_defconfig PLATFORM=generic

The compilation will finally generate platform/generic/firmware/fw_dynamic.itb.

Compile u-boot

cd bsp-src/uboot-2022.10
make k1_defconfig
make -j$(nproc)

The compilation will generate u-boot-env-default.bin based on board/spacemit/k1-x/k1-x.env, which corresponds to the image of the env partition in the partition table, and will also generate FSBL.bin and u-boot.itb.

Compile linux

cd bsp-src/linux-6.6
make k1_defconfig
LOCALVERSION="" make -j$(nproc)