RISC-V Architecture Layer for OpenEmbedded/Yocto

This is the general hardware-specific BSP overlay for the RISC-V based devices.

More information can be found at: https://riscv.org/ (Official Site)

The core BSP part of meta-riscv should work with different OpenEmbedded/Yocto distributions and layer stacks, such as:

• Distro-less (only with OE-Core).
• Yoe Distro.
• Yocto/Poky.

This layer depends on:

• URI: https://github.com/openembedded/openembedded-core
  • branch: master
  • revision: HEAD
• URI: https://github.com/openembedded/bitbake
  • branch: master
  • revision: HEAD

Note: You only need this if you do not have an existing Yocto Project build environment.

Make sure to install the repo command by Google first.

mkdir riscv-yocto && cd riscv-yocto
repo init -u https://github.com/riscv/meta-riscv  -b master -m tools/manifests/riscv-yocto.xml
repo sync
repo start work --all

In order to bring all the layers up to date with upstream

cd riscv-yocto
repo sync
repo rebase

. ./meta-riscv/setup.sh

The different machines you can build for are:

• freedom-u540: The SiFive HiFive Unleashed board
• beaglev-starlight-jh7100: BeagleV - Based on Starlight JH7100 SOC

Note that this layer also provides improvements and features for the upstream qemuriscv32 and qemuriscv64 machines.

Additional beagleV notes on bringup are here

A console-only image for the 64-bit QEMU machine

MACHINE=qemuriscv64 bitbake core-image-full-cmdline
MACHINE=beaglev-starlight-jh7100 bitbake core-image-full-cmdline

To build an image to run on the HiFive Unleashed using Wayland run the following

MACHINE=freedom-u540 bitbake core-image-weston

To build an image to run on the BeagleV using Wayland run the following

MACHINE=beaglev-starlight-jh7100 bitbake core-image-weston

To build a full GUI equipped image running Plasma Mobile see the in-tree documentation here.

Run the 64-bit machine in QEMU using the following command:

MACHINE=qemuriscv64 runqemu nographic

Run the 32-bit machine in QEMU using the following command:

MACHINE=qemuriscv32 runqemu nographic

If you would like to boot the images from a TFTP server (optional) you should set your TFTP server address in your local.conf with the following line. Change 127.0.0.1 to the IP address of your TFTP server and copy the uImage to the server.

TFTP_SERVER_IP = "127.0.0.1"

To use the Microsemi expansion board with your HiFive Unleased add the following line to your local.conf. This tells the Unleashed to use a device tree with the PCIe device described:

RISCV_SBI_FDT:freedom-u540 = "hifive-unleashed-a00-microsemi.dtb"

The output of the build can also be written to an SD card using bmaptool, the steps to do this are below:

$ MACHINE=freedom-u540 wic create freedom-u540-opensbi -e core-image-minimal
$ bmaptool create ./freedom-u540-opensbi-201812181337-mmcblk.direct > image.bmap
$ sudo bmaptool copy --bmap image.bmap ./freedom-u540-opensbi-201812181337-mmcblk.direct /dev/sdX

The output of a freedom-u540 or beaglev-starlight-jh7100 build will be a <image>.wic.gz file. You can write this file to an sd card using:

$ zcat <image>-<machine>.wic.gz | sudo dd of=/dev/sdX bs=4M iflag=fullblock oflag=direct conv=fsync status=progress

• Khem Raj <raj dot khem at gmail.com>