Up Squared Audio DSP

System Requirements


The Zephyr SDK 0.11 or higher is required.

Since firmware binary signing for Audio DSP is mandatory on Intel products form Skylake onwards the signing tool and key are needed.

up_squared board is running Linux with SOF Diagnostic Driver 2 built and loaded.

Signing tool

rimage is Audio DSP firmware image creation and signing tool. The tool is used by Sound Open Firmware 3 to generate binary firmware signed images.

For the building instructions refer to rimage Build Instructions 4.

Signing keys

The key used is Intel Open Source Technology Center (OTC) community key. It can be freely used by anyone and intended for firmware developers. Please download and store private key from the location: https://github.com/thesofproject/sof/blob/master/keys/otc_private_key.pem

For more information about keys refer to rimage keys 5.

Setup up_squared board

To setup Linux on up_squared board refer to Getting Started with Ubuntu Core on an UP Squared Board 1.

After installing Linux build and install SOF Diagnostic Driver 2.

Programming and Debugging

Build Zephyr application

Applications can be build in the usual way (see Building an Application for more details). The only additional step required is signing. For example, for building hello_world application following steps are needed.

  1. Building Zephyr application hello_world

    # From the root of the zephyr repository
    west build -b intel_adsp_cavs15 samples/hello_world
  2. Sign and create firmware image

    west sign -t rimage -- -k <path to otc_private_key.pem>

Loading image to Audio DSP

SOF Diagnostic Driver 2 provide interface for firmware loading. Python tools in the board support directory use the interface to load firmware to ADSP.

Assume that the up_squared board’s host name is cavs15 (It also can be an ip address), and the user account is user. Then copy the python tool to the up_squared board from your build environment:

$ scp boards/xtensa/intel_adsp/tools/cavstool.py user@cavs15:

Note that the /dev/hda device file created by the diagnostic driver must be readable and writable by the process. So we simply by running the loader script as root:

cavs15$ sudo ./cavstool.py

Cavstool_server.py is a daemon which accepts a firmware image from a remote host and loads it into the ADSP. After successful firmware download, the daemon also sends any log messages or output back to the client.

Running and Debugging

While the python script is running on up_squared board, you can start load image and run the application by:

west flash --remote-host cavs15


west flash --remote-host 192.168.x.x

Then you can see the log message immediately:

Hello World! intel_adsp_cavs15

Integration Testing With Twister

The ADSP hardware also has integration for testing using the twister tool. The cavstool_client.py script can be used as the --device-serial-pty handler, and the west flash script should take a path to the same key file used above.

./scripts/twister --device-testing -p intel_adsp_cavs15 \
  --device-serial-pty $ZEPHYR_BASE/soc/xtensa/intel_adsp/tools/cavstool_client.py,cavs15,-l \
  --west-flash "--remote-host=cavs15,--pty"

And if you install the SOF software stack in rather than the default path, you also can specify the location of the rimage tool, signing key and the toml config, for example:

./scripts/twister --device-testing -p intel_adsp_cavs15 \
  --device-serial-pty $ZEPHYR_BASE/soc/xtensa/intel_adsp/tools/cavstool_client.py,cavs15,-l \
  --west-flash "--remote-host=cavs15,--pty\