probe-rs-linux

Linux probe drivers for probe-rs

This crate contains Linux-specific probe drivers for probe-rs:

• linuxgpiod — bit-bangs SWD over the Linux GPIO character-device interface (/dev/gpiochipN).
• linuxspidevswd — emulates SWD over a spidev SPI bus with PICO and POCI tied together through a series resistor.

Both drivers are no-ops on non-Linux targets so the crate always compiles.

Usage

Add the crate as a dependency in your Cargo.toml:

[dependencies]
probe-rs-linux = <current version>

Then register the plugin with probe-rs:

fn main() {
    probe_rs_linux::register_plugin();

    // ... rest of the code
}

linuxgpiod (bit-banged SWD over GPIO)

Select a probe with the synthetic selector 0:0:<gpiochip>,swclk=<offset>,swdio=<offset>[,srst=<offset>], where <gpiochip> is gpiochipN, /dev/gpiochipN, or just N:

probe-rs run --probe 0:0:gpiochip1,swclk=26,swdio=25,srst=38 \
    --chip STM32F439ZITx hello_world.elf

The VID:PID portion of the selector is ignored; the serial portion carries the chip-and-pin map. srst is optional.

linuxspidevswd (SWD over spidev)

Wiring on a Raspberry Pi

To use this backend on a Raspberry Pi, connect the SWD pins to the SPI GPIOs. Tie MOSI to MISO through a series resistor (typically 1 kΩ) and use that node as SWDIO. This driver does not assume the underlying spidev supports 3-wire mode. The Pi pinout for SPI0 is:

GPIO Pin	Function	Pin-header number
GPIO 10	SPI0 MOSI	19
GPIO 9	SPI0 MISO	21
GPIO 11	SPI0 SCLK	23

Run raspi-config to enable SPI on the Raspberry Pi, then reboot. After rebooting, you should see the spidev device at /dev/spidev0.0. You can then use this device with probe-rs to connect to your target via SWD.

Probe selection

Select the device directly with a synthetic selector that carries the spidev path in the serial portion:

probe-rs info --probe 0:0:/dev/spidev0.0

The VID:PID portion is ignored. For safety, probe-rs list only exposes explicit /dev/spidev_swd* udev links, so probe-rs does not implicitly try every SPI device on the system.

Cross-compiling for the Raspberry Pi

# pi1, pi-zero
cross build -p probe-rs-tools --target arm-unknown-linux-gnueabihf --release --features remote
# pi3, pi4, pi5
cross build -p probe-rs-tools --target aarch64-unknown-linux-gnu   --release --features remote

# copy the resulting binary to the Pi
scp target/arm-unknown-linux-gnueabihf/release/probe-rs pi-zero-w:~/

Running on the Raspberry Pi

Direct use on the Pi:

./probe-rs info --protocol swd --probe "0:0:/dev/spidev0.0" --speed 1000

To run as a remote server, create a server config TOML file on the Pi as described in the docs and run:

./probe-rs serve

With the Pi running as a server, drive it from your PC:

# check connection:
probe-rs --host ws://pi-zero-w.local:3000 --token "token" info \
    --protocol swd --speed 1000 --probe "0:0:/dev/spidev0.0"

# run a binary:
probe-rs --host ws://pi-zero-w.local:3000 --token "token" run hello_world.elf \
    --protocol swd --chip STM32F439ZITx --speed 1000 --log-file ./temp_probers_log

This has been tested on a Raspberry Pi Zero W with an STM32F439ZI target up to 16 MHz, though above 4–6 MHz little additional performance was observed.