Adding RPU Firmware to boot.bin

You can include an RPU executable in boot.bin by adding kas/conf/rpu-firmware.yml to the kas build configuration.

$ kas build kas/scobc-v1.yml:kas/conf/rpu-firmware.yml

The generated boot.bin contains the Zephyr philosophers sample as the RPU firmware by default. The firmware is configured to run on the RPU in lockstep mode.

Running the RPU Firmware

When the board is powered on from a boot device containing the generated boot.bin, the RPU starts automatically and executes the ELF file included in boot.bin.

The default philosophers sample produces output similar to the following:

$ tio /dev/ttyUSB2
Philosopher 0 [C:-2]   EATING  [  375 ms ]
Philosopher 1 [P: 2]  THINKING [  725 ms ]
Philosopher 2 [P: 1]  THINKING [  700 ms ]
Philosopher 3 [P: 0]    HOLDING ONE FORK
Philosopher 4 [C:-1]   EATING  [  600 ms ]
Philosopher 5 [C:-2]        STARVING

Demo Description
----------------
An implementation of a solution to the Dining Philosophers
problem (a classic multi-thread synchronization problem).
This particular implementation demonstrates the usage of multiple
preemptible and cooperative threads of differing priorities, as
well as dynamic mutexes and thread sleeping.

Using Custom RPU Firmware

To include a different RPU executable, set RPU_FIRMWARE_URI to the URI of the executable and RPU_FIRMWARE_SHA256 to its SHA-256 checksum before running the build.

$ export RPU_FIRMWARE_URI="file:///absolute/path/to/rpu-firmware.elf"
$ export RPU_FIRMWARE_SHA256="<SHA-256 checksum of rpu-firmware.elf>"
$ kas build kas/scobc-v1.yml:kas/conf/rpu-firmware.yml