deluge-linux

Linux on the Synthstrom Deluge, a Renesas RZ/A1L (single-core Cortex-A9 @ 400 MHz, 64 MB SDRAM). Mainline kernel with PREEMPT_RT, plus drivers for the instrument's own hardware: the pad grid, OLED, encoders, audio codec, MIDI, and CV/gate.

This repo is the BSP and the image factory, everything needed to go from nothing to a bootable Linux image. It's a Buildroot BR2_EXTERNAL tree: board files, kernel drivers, and patches that Buildroot assembles into U-Boot, the kernel, and the root filesystem. The repo root is the external tree, so there's no separate Buildroot checkout to manage.

Applications for the Deluge are built against libdeluge (C/C++) or deluge-sdk (Rust), which wrap the kernel ABI this repo exposes (documented in docs/drivers.md) and consumes the release bundle this repo publishes (documented in docs/release.md).

Status

Boots from the deluge-sdk app-loader off the SD card or over USB, and runs from SDRAM without writing the flash. The app-loader itself is installed once, like a firmware update; read Before you start first. Hardware-verified:

subsystem	driver	userspace interface
Audio out + in	deluge-ssi, deluge-audio	ALSA card Deluge (pcmC0D0p / pcmC0D0c)
DIN MIDI	deluge-midi	ALSA rawmidi (midiC0D0)
USB MIDI 2.0	f_midi2 gadget	ALSA UMP (umpC2D0)
OLED display	deluge-oled	fbdev fb1 (128×43)
Pad grid	deluge-pad	fbdev fb0 (18×8) + evdev multi-touch
Buttons	deluge-pic	evdev
Encoders (6×)	deluge-encoders	evdev
LEDs	leds-deluge	sysfs LEDs (36 indicators + 2 gold columns)
CV / gate	deluge-cv	IIO DAC (iio:device0) + GPIO lines
Clock in	deluge-clkin	evdev
Fast SRAM	deluge-sram	/dev/deluge-sram (1 MB, on-chip)
USB gadget	composite	CDC-ACM + UAC2 + MIDI 2.0, plus NCM on platform only (1d6b:0104)

Device numbers in the table (fb0, iio:device0, pcmC0D0p, …) are what a current image produces. They depend on probe order, so apps should resolve devices by name; docs/drivers.md lists the names.

Every tagged release ships the deluge-base bundle, which is what libdeluge and deluge-sdk consume to build app images without running Buildroot. See docs/release.md.

Quickstart

Just want to try it? Each release has a prebuilt LINUX.ELF: the platform image, which boots into the app launcher. Read Before you start, copy it to the SD card's /APPS/, and pick it from the app-loader's boot menu.

To build it yourself, you need a host compiler, make, git, and Buildroot's host prerequisites. The cross-toolchain is a prebuilt tarball Buildroot downloads, so you don't need one installed.

1. Install the prerequisites (Debian/Ubuntu package names; see CONTRIBUTING.md for what each is for):

   sudo apt install build-essential bc cpio file git rsync unzip wget python3 \
                    libncurses-dev device-tree-compiler python3-serial

2. Clone and build the appliance profile, the same image the Deluge's own app-loader boots (no shell, no login, just the instrument):

   git clone https://github.com/FirestormAudio/deluge-linux.git
   cd deluge-linux
   make base       # ~15 min cold on a multi-core desktop, mostly the kernel
   make appelf     # packs the result into out/LINUX.ELF

3. Get the image onto the board. Easiest is over USB, with no SD card: put the Deluge on its boot menu with DEV MODE on (see Before you start), then:

   python3 tools/devupload.py out/LINUX.ELF

   Copying out/LINUX.ELF to the SD card's /APPS/ and picking it from the boot menu works too. See docs/boot.md.

4. Verify it booted. The base profile has no login by design (its USB serial port shows kernel messages only), so what you'll see is the instrument's own UI coming up on the pad grid and OLED. For a shell and confirmation that the drivers loaded, build make platform instead; it adds a USB console and SSH, and boots into the app launcher for the apps in the card's /LINUX/APPS/. See docs/debugging.md.

   platform logs in as root with the password deluge, on the USB console and over SSH. Change it (BR2_TARGET_GENERIC_ROOT_PASSWD in configs/deluge_defconfig) before building, or don't use platform on a host or network you don't trust. See SECURITY.md.

Run make with no arguments for the full target list.

Layout

board/synthstrom/deluge/   the board: kernel drivers + DTS, U-Boot support, rootfs overlays
configs/                   Buildroot defconfig + the two profile fragments
package/                   Buildroot packages
scripts/                   installs the board's files into the upstream trees;
                           mk-bundle.sh assembles the release bundle
tools/                     host tools:
  mk-app-elf.py              pack out/ into the app-loader ELF
  check-app-elf.py           validate an app-loader ELF against the memory map
  deluge-mkimage             pack an app into an image from the release bundle
  devupload.py               boot an ELF over USB in DEV MODE
  net-connect.sh             host side of the platform profile's USB network
  deluge-midi-send.c         send MIDI 2.0 to the board's USB gadget via libusb
  gen-splash-fonts.py        regenerate the boot splash's font headers
tests/                     pytest suite for the Python tools
debug/                     J-Link / RTT harness
.buildroot/                pinned Buildroot, fetched by make (gitignored, throwaway)

board/synthstrom/deluge/ is the source of truth. Buildroot fetches pristine upstream sources and the scripts/install-*.sh hooks stamp the board's files into them at build time; nothing under .buildroot/ is ever edited by hand.

Docs

• CONTRIBUTING.md: the development workflow. Build prereqs, running the tests, adding a driver or package, patching upstream.
• docs/hardware.md: the board itself. The SoC, the peripherals, and how each one is wired. Start here.
• docs/launcher.md: the platform image's app launcher. Putting apps on the card, the escape chord, logs and shutdown.
• docs/boot.md: safety notes, app-loader to U-Boot to kernel, the memory map, and how to get an image onto the board.
• docs/drivers.md: the deluge-* drivers and the userspace ABI they expose, which is what libdeluge is written against.
• docs/debugging.md: the USB console (CDC-ACM) and network link, JTAG and the RTT console, and what to check when it won't boot.
• docs/release.md: the release bundle, CI, and how app builds consume what this repo produces.

License

GPL-2.0. The kernel drivers are derivative works of Linux; the U-Boot board support is GPL-2.0-or-later. The exception is the launcher in package/deluge-launcher/, which is GPL-3.0-or-later (see its LICENSE) because the deluge-sdk UI toolkit and fonts it builds on are.