csgordon/openbsd-vf2.md

## openbsd-vf2.md

      
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    Installing OpenBSD 7.3-current on a VisionFive2

Here are some concise instructions for getting OpenBSD 7.3-current running on a StarFive VisionFive 2 (v1.3B, though from other reports referenced below, it sounds like the v1.2 boards can also be made to work).
You will need:

An SD card of at least 1GB
An eMMC module attached to the board (though see below for a variation that should work to install directly to sd card)
Internet access
A USB TTL serial adapter that supports 3.3V (some of these support multiple voltages, but if yours only supports other voltages and not 3.3 it will either not work or damage your board!)
A second machine to interact with the VF2 over serial

Before you start


Verify that the board boots StarFive's Debian or Fedora fork. For 1.2 boards you might need to update firmware, for my 1.3 board the June 2023 Debian image worked perfectly when the board was set to boot from SD.
Verify that the eMMC is inserted correctly. I, and others on the StarFive boards, have had trouble getting this seated correctly. If you can see it from Linux you're good to go. If you jumped ahead and nuked the sd card with your Linux image already, you can try to verify this from the u-boot prompt (see below to get there) with mmc dev 0, and if it's actually formatted you could try ls mmc 0:1 / depending on the filesystem.

Personally verified instructions


Burn install73.img from -current snapshots for riscv64 to an sd card
Mount the EFI partition and drop the dtb from this mailing list post in there, in the root of the partition: https://marc.info/?l=openbsd-misc&m=169046816826966&w=2. This is a file specific to board version 1.3B, though it sounds like it might have been used successfully on a v1.2 board. YMMV, I only have a 1.3B.
Eject the SD card from where you wrote it, stick it in the VF2
Attach the serial adapter to the appropriate GPIO pins on the VF2, as on page 35 of the quick start guide: https://doc-en.rvspace.org/VisionFive2/PDF/VisionFive2_QSG.pdf (see Figure 4-1)
Attach the USB end to whatever machine you're using.
Kick off a serial connection from the other machine. You might have to dig around for examples, but this step is the same as for Raspberry Pis, which makes instructions easier to come by.


On FreeBSD, I run sudo screen /dev/cuaU0 115200
On MacOS, I run sudo screen /dev/cu.URT0 115200


Boot the board (v1.3b) to the u-boot prompt from the internal u-boot (switches to 0,0), hit a key (in the terminal connection on the other computer!) to interrupt (in theory you could wait for it to time out), and run the commands from that post:

load mmc 1:1 ${fdt_addr_r} jh7110-starfive-visionfive-2-v1.3b.dtb
load mmc 1:1 ${kernel_addr_r} efi/boot/bootriscv64.efi
bootefi ${kernel_addr_r} ${fdt_addr_r}


If either of the first two commands fail, check that the card is inserted correctly, and that you inserted before powering on the VF2. (Technically you can re-probe the sd card with mmc rescan and mmc device 1, but this is sometimes flaky for me.)


Follow the install process as you typically would! The eMMC device should show up as sd0, the sd card is sd1. Choose the eMMC as the installation target, and when it gets to installing sets, choose disk, and follow the steps to mount sd1.
Reboot, this time using 0:1 (first partition of mmc device 0, the eMMC) in the second command that loads the  (but not the first, since the dtb file is still only on the sd card!)
Log in, mount the EFI partition on your eMMC, and the sd card, and copy the same dtb file from the EFI partition on the sd card to the EFI partition on the  eMMC


Unless you did some serious customization to your install, this should be the only FAT partition that shows up when you ask disklabel to show the eMMC's partitions.
Technically you should be able to mount the eMMC card's EFI partition and copy this over at the end of your install process if you want to, but I did not think to do this


You can now boot without the sd card, using 0:1 in both commands. The adventurous could set this as the default boot sequence in u-boot.

Speculative: Installing to SD Card or NVMe

The instructions above assume you have an eMMC module installed, as I did. But in theory installing to an SD card or NVMe is possible.
Installing to SD Card

If you only have an SD card, there's a way to boot the install process off the same media you're going to install to, as long as you have internet access during the install.
Grab miniroot73.img instead of install73. Boot as instructed, but when you get to installing sets you'll need an internet connection. Type ! to temporarily escape to a shell very early in the process, before configuring network, and use the date command to set the date, or SSL won't work. Then exit the shell back to the install program, and carry on, selecting the sd card as the destination. You can then choose http as the source for disk sets.  This will, however, overwrite your install media, so if something goes wrong be prepared to re-image miniroot73.img.
I did try this once but was having difficulty when specifying cdn.openbsd.org as the server (verifications were failing, the connection seemed flaky). I assumed at the time that the issue was my home internet (which is sometimes flaky) or the wifi dongle, but I've since discovered that this sometimes happens with the cdn server (https://dev.to/nabbisen/openbsd-pkgadd-didnt-work-due-to-ocsp-verify-failed-53b2). Instead, use ftp.openbsd.org, which is what I've since used to follow this approach on a Raspberry Pi 4B.
I haven't tried it, but have seen reports (LINK) that the wired ethernet works in at least one port, in which case you can use that. Or, if you have a wifi dongle compatible with OpenBSD, it should be recognized and usable during installation (I did configure my realtek dongle during one boot from the install media).
Another option, if you have a USB CD drive lying around: yes, that's right, you could download the sets (for the right architecture!) and burn them to a CD. I happen to have one plugged into the USB hub I used with my VF2, and it's detected during setup.
Installing to NVMe

I don't have an NVMe, but it has been done using edk2: https://marc.info/?l=openbsd-misc&m=169048799607277&w=2
Note, however, that if you stick a high-power NVMe drive in the VF2, it may draw too much power to be stable: https://forum.rvspace.org/t/unlocking-new-possibilities-starfive-visionfive-2-sbc-now-supports-tianocore-edk-ii-uefi/2779/42
Speculative: Cleaning up the boot sequence

Manually typing the load commands into u-boot every time is not pleasant. In principle, it should be possible to extend the onboard u-boot's settings with an option to try those manually (in addition to the things it tries by default).
Speculative: Getting a real TTY

The OpenBSD ARM install file notes that the OpenBSD boot loader --- which is what runs immediately after the bootefi command, and briefly gives you a prompt before booting the kernel --- can be directed to use a framebuffer for the serial device by typing set tty fb0 before the prompt times out. Presumably there's a way to set that permanently (on FreeBSD it would be a setting in /etc/boot.conf) but I haven't figured that out yet, or tried manually. I can see from dmesg output that my USB keyboard is detected.
What Works, What Doesn't

All critically depending on this one DTB...
Working


Storage on SD card and eMMC
PCIe and USB

Notably, USB peripherals that are supported on other platforms work, such as a Realtek wifi dongle using the urtwn driver


Notable not working / unimplemented

Mostly graphics support
Untested / Unexamined

Framebuffer support, GPIO pins (beyond serial), various extra board connectors (CSI, DSI), cpu temp, cpu frequency control, wired ethernet (though this is reported to work)
What's Happening in Step 8

I'll fill this in later with more detail, but basically we're telling u-boot to load the specific DTB from the SD card, and pass its contents to the OpenBSD loader, so the loader can in turn pass a reasonably-accurate device tree to the kernel. Without this, the kernel won't be able to locate various onboard devices and/or won't know the right settings to communicate with the devices.
Resources I used to get here

I originally set out to figure out if I could run FreeBSD on this device, not OpenBSD, because I am actually an active FreeBSD user. That search led me to a forum post:

https://forum.rvspace.org/t/freebsd-support/1313/8

Which in turn linked to:

A toolkit for booting the FreeBSD kernel plus a ramdisk, but without any driver support (even storage): https://github.com/robn/freebsd-vf2
A number of links to OpenBSD source changes for the VF2 (more precisely, the JH7110), which got me interested in seeing how OpenBSD worked on the board

After much, much more digging, I eventually found a very useful Reddit thread:

https://www.reddit.com/r/openbsd/comments/144f9wm/comment/jtnrtpv/ (whole thread)

Which linked to other interesting resources, but critically to the mailing list thread where someone had posted an actual DTB used for some of the OpenBSD support work:

https://marc.info/?l=openbsd-misc&m=169046816826966&w=2

Earlier I also found the record of someone trying to walk the same path as me before, of getting FreeBSD up and running on this to do some driver development: https://adventurist.me/posts/00315. Since that post, the documentation situation has gotten somewhat (slightly) better; not only did the OpenBSD developers find some useful info somewhere, it turns out the same chipset is used in the Pine64 Star64, and they have found much more informative datasheets than anything I could find on StarFive's wiki: https://wiki.pine64.org/wiki/STAR64#Datasheets_for_Components_and_Peripherals.
Now that I've confirmed the OpenBSD drivers work, I'm going to (a) use OpenBSD a bit(!), and (b) try porting some drivers to FreeBSD, since compared to the last person to try this, I have the benefit of working OpenBSD drivers to go off of, and seemingly slightly better technical documentation (not sure how much better).  I've already got a full cross-build of world and kernel for riscv64 from an amd64 machine (I'll write up those directions at some point, it took a bit of digging and cross-referencing), so we'll see how that goes. Some of the OpenBSD driver changes are actually minor adjustments to existing drivers to just recognize additional devices, but I'm not yet sure of the dependency order among drivers. I just hope the storage isn't connected via PCIe, I don't want that to be the first driver I have to port!  If I actually get somewhere, maybe I'll pick up a Star64 too...