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Toolchains and Application Development

RISC-V Linux Toolchain​

The Linux user-space toolchain is normally under prebuilt/rootfsbuilt. Its prefix depends on the selected board and musl/glibc configuration. Locate it first:

which gcc
find prebuilt -type f -name '*gcc' | head

Build a simple program:

${CROSS_COMPILE}gcc -O2 -Wall hello.c -o hello
file hello

Shared library:

${CROSS_COMPILE}gcc -fPIC -c demo.c -o demo.o
${CROSS_COMPILE}gcc -shared demo.o -o libdemo.so

Static library:

${CROSS_COMPILE}gcc -c demo.c -o demo.o
${CROSS_COMPILE}ar rcs libdemo.a demo.o

RISC-V MCU Toolchain​

The MCU toolchain is for RTOS projects and must not be mixed with the Linux user-space toolchain. Use the SDK mrtos build system so that the correct ABI and architecture flags are applied automatically.

Git/Gitea Workflow​

Create a clean vendor baseline:

git init
git switch -c main
git add .
git commit -m 'baseline: vendor V821 SDK'
git remote add origin <gitea-url>
git push -u origin main

quick_config, storage switching, and camera switching modify multiple files. Use a separate branch for each feature and inspect git status and git diff before and after the operation.

Adding a Tina Package​

Typical layout:

openwrt/package/utils/hello/
├── Makefile
└── src/
    ├── Makefile
    └── hello.c

The OpenWrt package Makefile defines metadata, dependencies, build steps, and rootfs installation. Then enable and build it:

make menuconfig
# select Utilities -> hello
m -j4

Auto-start Service​

Prefer an OpenWrt init script:

/etc/init.d/hello

Implement at least start() and stop(), and install the enable link from the package. For temporary board-side testing:

/etc/init.d/hello enable
/etc/init.d/hello start

The application should handle missing configuration, unavailable storage, delayed networking, and abnormal exits. A background command in rc.local is not a robust service design.