Up Squared Audio DSP
System Requirements
Prerequisites
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.
Building Zephyr application
hello_world# From the root of the zephyr repository west build -b intel_adsp_cavs15 samples/hello_world
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.
Note that the /dev/hda device file created by the diagnostic
driver must be readable and writable by the process. This can be
accomplished via a simple chmod, via a udev handler that associates
the device with a particular user or group, or simply by running the
loader script as root:
$ sudo chmod 777 /dev/hda
$ boards/xtensa/intel_adsp_cavs15/tools/fw_loader.py -f <path to zephyr.ri>
Debugging
The only way to debug application is using logging. Logging and ADSP logging backend needs to be enabled in the application configuration.
ADSP logging backend writes logs to the ring buffer in the shared memory.
As above, the adsplog tool requires appropriate permissions, in
this case to the sysfs “resource4” device on the appropriate PCI
device. This can likewise be managed via any filesystem, setuid or
udev trick the operator prefers.
$ boards/xtensa/intel_adsp_cavs15/tools/adsplog.py
ERROR: Cannot open /sys/bus/pci/devices/0000:00:0e.0/resource4 for reading
$ sudo chmod 666 /sys/bus/pci/devices/0000:00:0e.0/resource4
$ boards/xtensa/intel_adsp_cavs15/tools/adsplog.py
Hello World! intel_adsp_cavs15
Integration Testing With Twister
The ADSP hardware also has integration for testing using the twister
tool. The adsplog 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. Remember to pass the
--no-history argument to adsplog.py, because by default it
will dump the current log buffer, which may contain output from a
previous test run.
$ZEPHYR_BASE/scripts/twister --device-testing -p intel_adsp_cavs15 \
--device-serial-pty $ZEPHYR_BASE/boards/xtensa/intel_adsp_cavs15/tools/adsplog.py,--no-history \
--west-flash $ZEPHYR_BASE/boards/xtensa/intel_adsp_cavs15/tools/flash.sh,$PATH_TO_KEYFILE.pem