`make load` on a Kosagi FOMU board

[FelipeWcosta]

Hello everyone!

I am try to use CFU-Playground to load a minimal Vexriscv CPU added of a CFU because the FOMU board does not have resoucers enough to synthesize the full version of Vexriscv. Then, first of all I fixed the error that was occur when I was gonna attach the board into my Ubuntu-22.04 Virtual Machine, for this I just update the firmware with dfu-util:

 Fomu PVT running DFU Bootloader v1.9.1 -> Fomu PVT running DFU Bootloader v2.0.4

Following this tutorial.

The next step was made the board be available in the USB port, to do that, I just followed this steps. When I run dfu-util -l the log is:

dfu-util 0.11-dev

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2021 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

Found DFU: [1209:5bf0] ver=0101, devnum=3, cfg=1, intf=0, path="1-1", alt=0, name="Fomu PVT running DFU Bootloader v2.0.4", serial="UNKNOWN"

It is ok, I can load some hardware descriptions into FOMU board.

Then, I followed the CFU-Playground setup guide running make env and make enter to set a environment for Lattice FPGA's. I navigate to proj_template directory and runned make TARGET=kosagi_fomu EXTRA_LITE_ARGS="--cpu-variant=minimal+cfu" prog and the the compilation ends with:

And I runned make TARGET=kosagi_fomu EXTRA_LITE_ARGS="--cpu-variant=minimal+cfu" load, the result was this:

But, there is no /dev/ttyUSB0 available, for example, to attach the board:

And doing lsusb I can see the bootloader:

If someone can help me to fix it, I would appreciate!

[FelipeWcosta]

So, I closed this issue because I can runned the Person Detection int8 model on kosagi fomu with a manual way. The script don't load the image binary file by itself then I loaded it using dfu-util -D image.bin.dfu follow by the command sudo screen /dev/ttyACM0 and finally I could see the CFU-Playground menu.

There is a binary file called image.bin but it cause an erro and I cannot see any error with fomu workflow.

[FelipeWcosta]

The last update, I changed the programmer to use DFU directly on Fomu workflow and worked very well.

[tcal-x]

Hi @FelipeWcosta , I'm sorry I was not able to help earlier! Unfortunately your Fomu adventure coincided with 3 weeks of my travel away from keyboard.

I think you discovered the main issue, that the tty appears at /dev/ttyACM0 usually. Our suggested hack is to specify the TTY on the make line: make TARGET=kosagi_fomu .... TTY=/dev/ttyACM0 load. With this, it should be able to load the bitstream and the software together. There may be more tips that you find useful at https://github.com/google/CFU-Playground/wiki/Supported-Boards#fomu

We have 'fomu' and 'fomu+cfu' variants that also fit on the Fomu board and may give a bit more performance than the 'minimal' variants. If you try to use a variant other than 'fomu' or 'minimal', there is some scripting that will automatically substitute a 'fomu' variant for you. There is a short comment in the LiteX output that scrolls by, so it's easy to miss.

I'm not sure of your current status -- does everything seem to work for you if you use the TTY=/dev/ttyACM0 define?

[FelipeWcosta]

Hi @tcal-x, I've been working on using CFU-Playground with kosagi fomu board. In a first moment, I find out a problem to attach the board to my VM that was fixed updating the bootloader (in the first comment) and then the image.bin was not loaded directly by the fomu workflow script so I did this manually using DFU and some more commands and worked.

Looking at the fomu workflow script I changed to use only the DFU to program the board:

prog = dfu.DFUProg(pid='5bf0', vid='1209')

Finally, when I run make TARGET=kosagi_fomu EXTRA_LITE_ARGS="--cpu-variant=minimal+cfu" load TTY=/dev/ttyACM0 it's working fine.

Some considerations, the execution of the person detection model is very slow and considerably increases the number of cycles, I suppose it is because of the minimal version of vexriscv that very possibly has fewer resources.