syfala-linux getting started

Requirements

gcc-arm-none-eabi gnutls-dev bison flex libssl-dev bc u-boot-tools cpio libyaml-dev curl kmod squashfs-tools qemu-user-static

Building

Available commands

From scratch

First, a regular syfala project has to be built with the following options: 

syfala examples/virtualAnalog.dsp --linux

The --linux option is used for compiling the host-side (ARM) application with the linux-specific source files (otherwise, it would be compiling the standard baremetal one).

After synthesis, the script will detect that you don't currently have a linux build, which is required for building the application, and will download and build everything for you, you'll just have to flash it to your formatted SD card afterwards

Outputs

The build outputs are located in thebuild-linux/output directory, with two distinct boot and root subdirectories, which then will have to be be flashed on the first and second partitions of your SD card.

Usage

Formatting the SD card

The SD card has to be formatted like so:

There are many ways to achieve this, for instance:

# you can just replace </dev/...> with your SD device, e.g: /dev/sda or /dev/mmcblk0
sudo parted /dev/... --script -- mklabel msdos
sudo parted /dev/... --script -- mkpart primary fat32 1MiB 128MiB
sudo parted /dev/... --script -- mkpart primary ext4 128MiB 100%
sudo parted /dev/... --script -- set 1 boot on
sudo parted /dev/... --script -- set 1 lba on
sudo mkfs.vfat /dev/device-partition-1 # e.g. /dev/sda1
sudo mkfs.ext4 /dev/device-partition-2 # e.g. /dev/sda2
sudo parted /dev/... --script print

Flashing boot & root partitions

# In case your SD device is /dev/sda
# 1. Copying boot partition files
sudo mount /dev/sda1 /mnt
sudo cp -r build-linux/output/boot/* /mnt
sync
sudo umount /mnt
# 2. Copying root partition contents
sudo mount /dev/sda2 /mnt
sudo cp -r ~/Repositories/syfala/dev/main/build-linux/root/alpine-3.19.1/alpine-root/* .
# This might take a while...
sync 
sudo umount /mnt

Booting

Once flashed, just insert the SD card in your device's socket, make also sure it is configured to boot on SD (For the Zybo boards, you'll have to place a shorting jumper on SD instead of JTAG/QSPI).

Connecting

You can still connect through the ttyUSB Serial Port, or with SSH.

minicom -b 115200 -D/dev/ttyUSB1 -8

(check hardware flow control in minicom, ctrl-A Z). Linux booting console will appear. A login prompt will appear as soon as the booting process has completed:

Welcome to Alpine Linux 3.17
Kernel 6.6.0-xilinx on an armv7l (/dev/ttyPS0)

syfala login: 

ssh root@192.168.0.1 .

Login/users

The rootfs has the same structure as any Linux build. All DSP builds are located in the/root/ directory

Faust DSP builds

All the DSP builds made with the syfala toolchain are placed in the /root directory by default. For instance, if you make a build from the virtualAnalog.dsp file , the bitstream/application outputs will be located in:

You can then use the 

syfala-load <target> [--list | --help]

utility command (e.g. syfala-load virtualAnalog), which will take care of loading the bitstream and executing the app properly.

You can also do all of that manually of course: first, load the bitstream by entering the following command line:

fpgautil -b /root/virtualAnalog/bitstream.bin

and then execute the Host application like you would normally do with a Linux binary:

cd /root/virtualAnalog
./application.elf

If you wish to add another build to the SD card, you just have to re-run the syfala toolchain normally on your computer, with the --linux option. Your previous builds won't be erased or modified.

syfala examples/fm.dsp --linux

Once the build is complete, you will have two distinct project directories in yourbuild-linux/root/alpine-3.19.1/alpine-root/ directory:

You will then have to re-flash your SD card to update the root partition, or directly copy the directory through ssh (e.g. with the scp command).

Getting the device's IP & port from avahi (for network-based control)

Once a DSP target is loaded with the syfala-load command, an avahi service is automatically started in a separate thread. If your desktop machine is on the same network as the FPGA board, and you have avahi installed & running, you should be able to retrieve the FPGA board's IP address and port required for the HTTP/OSC controls. You can use the avahi-browse command in order to do so:

avahi-browse _syfala._tcp --resolve

HTTP control

In order to build a target with HTTP support, you can add the --http flag to the command line:

syfala examples/fm.dsp --linux --http

After loading a DSP target with the syfala-load command (or manually), the host application will create a HTTP server allowing users to control the Faust DSP parameters remotely (given that you are on the same network as your FPGA board).

At runtime, when executed, the application will print the device's current network IP (IPv4), and the port used by the HTTP server. You can then use any web browser, and control the application by entering the server's URL, for example http://192.168.0.1:5510

OSC control

In order to build a target with OSC support, you can add the --osc flag to the command line:

syfala examples/fm.dsp --linux --osc

Note: your Faust .dsp file must also contain this line in order to enable OSC support:

declare options "[osc:on]";

In parallel, the Host application will also create an Open Sound Control-compliant UDP server, and print its send/receive ports when executed. You can then control remotely the Faust DSP parameters by sending OSC messages like so:

More on: https://faustdoc.grame.fr/manual/osc/

MIDI control

In order to build a target with MIDI support, you can add the --midi flag to the command line:

syfala examples/fm.dsp --linux --midi

Note: your Faust .dsp file must also contain this line in order to enable MIDI support:

declare options "[midi:on]";

The Zybo boards have a Host USB port, located next to the switches. It can be used to connect a MIDI device and map its controls accordingly. No additional driver configuration is needed, but the board needs to be powered from an external power supply source:

The supply must use a center-positive 2.1mm internal-diameter plug and deliver between 4.5V to 5.5V DC. It should also be able to output at least 2.5 A (12.5 Watts) in order to support power-hungry Zynq projects and external peripherals. To use an external supply with a barrel jack, plug it into the power jack (J17), set jumper JP6 to “WALL”, and then set SW4 to “ON”.

You'll also have to put a shorting jumper on JP2 (HOST), next to the USB port.

The Faust midi-mapping process is explained here: https://faustdoc.grame.fr/manual/midi/

Wi-Fi

Wi-Fi is handled by iwd (provided you have an USB dongle, or the appropriate additional hardware, which Zybo boards do not possess natively), the available commands are: 

# List your available wifi device(s), look for wlan0
iwctl device list
# If you don't know the SSID of your network, you can run a scan and retrieve a list of all the detected networks:
iwctl station wlan0 scan && iwctl station wlan0 get-networks
# To connect to a network (use connect-hidden if it is a private network):
iwctl station wlan0 connect <SSID>

more on: https://wiki.alpinelinux.org/wiki/Wi-Fi

Autologin / Autostart DSP target

In order to autologin as root on the board, you have to edit the file /etc/inittab like the following:

#ttyPS0::respawn:/sbin/getty -L ttyPS0 115200 vt100
# For autologin (as root): comment out the previous line and uncomment the next one:
ttyPS0::respawn:/sbin/mingetty --autologin root --noclear ttyPS0 115200 vt100

To autostart a DSP target on boot, create a .start file in /etc/local.d , for example /etc/local.d/virtualAnalog.start:

#!/bin/sh
syfala-load virtualAnalog

Execute chmod 755 /etc/local.d/virtualAnalog . That's it!