Longan Configuration and Build

Longan builds the T527 bootloader, kernel, BSP, Device Tree, and firmware inputs. Run its configuration and build commands from the Longan root.

cd <ANDROID_TOP>/longan
pwd
ls build.sh bsp device kernel

Select a Target

./build.sh config

A typical Linux BSP selection is:

platform  : linux
linux_dev : bsp
kern_ver  : linux-5.15
ic        : t527
board     : <BOARD>
flash     : default

A typical Android selection is:

platform  : android
ic        : t527
board     : <BOARD>
flash     : default

Use the board list printed by the current branch. Common names include demo, demo_car, and demo_linux_aiot, but company branches may use custom targets.

Inspect the generated configuration:

cat .buildconfig

Important variables include LICHEE_PLATFORM, LICHEE_IC, LICHEE_BOARD, LICHEE_KERN_VER, LICHEE_KERN_DEFCONF, LICHEE_PACK_HOOK, and LICHEE_OUT_DIR.

Common Commands

Command	Purpose
./build.sh config	Select platform, chip, board, and flash
./build.sh	Build the current Longan target
./build.sh bootloader	Build boot0 and U-Boot components
./build.sh kernel	Build kernel, BSP, DTS, and modules
./build.sh menuconfig	Open kernel configuration
./build.sh saveconfig	Save kernel configuration
./build.sh loadconfig <defconfig>	Load a selected defconfig
./build.sh buildroot	Build the Buildroot target
./build.sh buildroot_menuconfig	Open Buildroot configuration
./build.sh buildroot_saveconfig	Save Buildroot configuration
./build.sh pack	Package a Linux image or invoke the configured pack hook
./build.sh pack_debug	Package with the debug serial-port setting
./build.sh clean	Clean the current target output
./build.sh distclean	Remove additional generated configuration and output

Full Android firmware is commonly packaged from the Android root with pack or build -p. Whether ./build.sh pack works for Android depends on the branch and LICHEE_PACK_HOOK.

Directory Shortcuts

Some SDKs provide:

source build/envsetup.sh
cbsp
ckernel
cconfigs

Use direct paths and find when those shell functions are not available.

Locate Output

find out -maxdepth 5 -type f \
    \( -name 'vmlinux' -o -name '*.dtb' -o -name '*.ko' -o -name '*.img' \) \
    -print | head -100

Common locations include out/t527/<BOARD>/kernel/build/, kernel/staging/, pack_out/, and the top-level image output.