VSS to VHAL mapper.

[jankubovy]

This mapper should serve as a basis for the ongoing generic VHAL discussions. See the docs/vhal.md for more information.

[mikehaller]

Would you be able to provide an example vss_to_android_property_map.json ?

[jankubovy]

Would you be able to provide an example vss_to_android_property_map.json ?

Just generate one with:
vspec export jsonvhal --vspec /path/to/vehicle_signal_specification/spec/VehicleSignalSpecification.vspec --min-property-id 32768 --vhal-map vss_to_android_property_map.json --output-dir /path/to/output

The --vhal-map is input/output. If the file does not exist it will be created. You just need to point to checked out https://github.com/COVESA/vehicle_signal_specification with the --vspec param.

Eventually COVESA should maintain a common vss_to_android_property_map.json but that should be discussed further. For now and testing everyone can just generate their own.

[jankubovy]

Would you be able to provide an example vss_to_android_property_map.json ?

@mikehaller there are minimal examples in the tests if you just want to see how it may look like. E.g. tests/vspec/test_static_uids_vhal/validation_jsons/validation_group_1_min_32768.json

[erikbosch]

MoM:

• Presented at meeting

[slawr]

From the doc (https://github.com/COVESA/vss-tools/blob/a2c86a73c939c0818d88116771461c7186aee2c1/docs/vhal.md#property-change-mode):

STATIC : used to VSS node types ATTRIBUTE and ACTUATOR

Can you explain why an VSS actuator node has a static change mode? Perhaps I misunderstand the meaning of change mode in the mapper.

[jankubovy]

From the doc (https://github.com/COVESA/vss-tools/blob/a2c86a73c939c0818d88116771461c7186aee2c1/docs/vhal.md#property-change-mode):

STATIC : used to VSS node types ATTRIBUTE and ACTUATOR

Can you explain why an VSS actuator node has a static change mode? Perhaps I misunderstand the meaning of change mode in the mapper.

Hi, I have overlooked https://covesa.github.io/vehicle_signal_specification/rule_set/data_entry/sensor_actuator/#actuator-type:

..., can be read and written. ...

should be same as sensor. I will fix that.

[erikbosch]

Thanks for the updates @jankubovy . Is the PR ready to review (and later merge) - if so change status to "ready to review"

[erikbosch]

MoM:

• Please review/discuss
• See also PDF at https://wiki.covesa.global/display/WIK4/Automotive+AOSP+App+Framework+Standardization+Expert+Group#AutomotiveAOSPAppFrameworkStandardizationExpertGroup-Agenda2025-07-28

[jankubovy]

Thanks for the updates @jankubovy . Is the PR ready to review (and later merge) - if so change status to "ready to review"

Hi @erikbosch I would merge it when the output, the VHAL exporter here is producing, is actually going to be used in the VHAL project. That project did not start yet, therefore I would not merge this PR yet. What do you think?

[erikbosch]

Thanks for the clarification @jankubovy. Based on that explanation I see no problem keeping it in Draft status. We do not have any major refactoring for vss-tools planned, so should in general not be a too big risk for regressions due to changes in vss-tools framework.

[sschleemilch]

should be in dev dependencies but I guess that's what the x is for?

[renjithrajagopal-sudo]

@jankubovy Thanks for reference. Have you done some mapping of data types of VSS vs VHAL & it's incompatibility somewhere ? Will VSS change for VHAL ? E.g Vehicle.Chassis.SteeringWheel.Angle is int16 where as VHAL is Float.

@petervolvowinz Mapping file could be a reference for your semantic matching tool though that is applicable for VHAL to VSS as well.

[jankubovy]

Have you done some mapping of data types of VSS vs VHAL & it's incompatibility somewhere ? Will VSS change for VHAL ? E.g Vehicle.Chassis.SteeringWheel.Angle is int16 where as VHAL is Float.

Hi @renjithrajagopal-sudo we have the field "formula" for mapping differences like those you are mentioning. Still work in progress. As of now such conversions have to entered manually in the generated mapping file. But it will be preserved on future runs of the mapper.

[renjithrajagopal-sudo]

Have you done some mapping of data types of VSS vs VHAL & it's incompatibility somewhere ? Will VSS change for VHAL ? E.g Vehicle.Chassis.SteeringWheel.Angle is int16 where as VHAL is Float.

Hi @renjithrajagopal-sudo we have the field "formula" for mapping differences like those you are mentioning. Still work in progress. As of now such conversions have to entered manually in the generated mapping file. But it will be preserved on future runs of the mapper.

Ok. Do you mean both range and scale will be preserved under this formula as well for similar use case? E.g A float which was converted to int16(due to VSS) then VSS to VHAL which expects float. Subsystem(100.34) -> VSS(10034) -> VHAL(100.34) , then formula validates range and know scale of 100