About
Porting OpenWrt to RISC-V ISA.
Release early, release offen. So far it can build the vmlinux & ext4 image and boot up on riscv-qemu successfully. But it still need many works to do and lots of test, check the TODO List and Known Problems.
How to play
Prerequesites
- Ubuntu (I use 14.04 LTS) with the packages installed sudo apt-get git-core build-essential libssl-dev libncurses5-dev unzip gawk python2.7 subversion
- qemu-system-riscv installed (riscv-qemu])
- Bootloader(bbl) from here or build it by yourself.
Build
In terminal.
# clone and checkout
git clone https://github.com/xfguo/riscv-openwrt.git
cd riscv-openwrt
git checkout riscv-port
# todo: update and install packages feed,
# but there are some issue when compile kmods, we will fix it later
# ./scripts/feeds update -a
# ./scripts/feeds install -a
# temperory step, later will be removed.
cp openwrt.config .config
# config
make menuconfig
# start to build, N=6 is my preferd.
# if something error and stop, use make V=s to check the error.
make -jN [V=s]
Run on Qemu Simulator
If the buld has no error, the results will be placed at bin/riscv64-glibc
, try run it with qemu.
qemu-system-riscv -kernel BBL_PATH/bbl -append bin/riscv64-glibc/openwrt-riscv64-vmlinux.elf -drive file=bin/riscv64-glibc/openwrt-riscv64-ext4.img,format=raw -nographic
TODO List/Known Problems
TODOs
- Many temperory scripts exists and some of them need be checked:
toolchain/*
include/site/riscv64
- Support both RISCV32/64, and
target/linux/riscv64
->target/linux/riscv
. - OpenWrt trunk use gcc 5.2.0 but RISC-V use 5.3.0, patches need be checked.
- Now it use
CONFIG_KERNEL_GIT_CLONE_URI
to clone linux from riscv-openwrt-linux, later it need to become to vanilla kernel + patches. - Now it use gcc/binutils/glibc source code packages generated by project riscv-gnu-toolchain to build the toolchain (download from riscv-openwrt-files), later it need to become to official packages + patches.
- Support initramfs, a disk file must be attached when run riscv-qemu, how to disable it?
- More RISC-V devices and boards support.
- Of course, finally, contribute the port to OpenWrt community as a new arch.
Problems
- Failed when built kernel modules, seems riscv-linux port missing
ksymb.c
and export them. - It works basiclly fine with
CPU selection=Rocket
but it seems to stuck somewhere when boot that built withCPU selection=Generic RISC-V
config.
RISC-V Port Authors
- Alex Guo (xfguo@xfguo.org)