Configuration Management

Configuration Management		status: draft safety: ASIL_B
tags: contribution_request, feature_request
doc__config_mgmt		Generic Document

Feature flag

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experimental_config_mgmt

Abstract

Configuration Management feature is responsible for central storage, verification and modification of individual vehicle configuration properties. A generic interface for applications to access such properties is part of the feature.

Motivation

Embedded software usually needs specific adaptations to a particular vehicle in terms of configuration properties. Such configuration properties are called parameters in the following abstract. Examples of parameters are vehicle geometry or geographical region of use. Parameters are used in manifold computations and are expected to be constant during a driving cycle in customers’ hand. Currently we differentiate between two kinds of parameters depending on type of configuration and related development process: coding parameters and calibration parameters.

ConfigDaemon application implements an on-target data base for all parameters used in a particular ECU and a generic interface for parameter accesses by user applications.

The basic idea of ConfigDaemon is justified by the use case of having only flexible runtime dependencies on parameters from the viewpoint of a user application. Generic interface to access a parameter is defined by key-value principle, where key is a unique name for a required parameter and value is any data related to this name. Runtime dependencies have an added value in comparison to statically defined interfaces for every specific parameter, which must be resolved at build time. This approach allows to shorten build times and avoids the necessity of system model changes and following re-builds if a parameter changes.

ConfigDaemon is internally structured as

• an application, which implements a parameter data base and interface for parameter access and

• additional plugins, which handle specific kinds of parameters according to OEM functional requirements, like

• coding plugin or

• calibration plugin

Flexibility of the generic interface is achieved by representation of any parameter value as a string. To convert the string representation to the original data type of a parameter an additional library ConfigProvider is offered. ConfigProvider is supposed to be integrated in a user application. ConfigProvider, thus, is responsible for

• establishing of communication to ConfigDaemon,

• receiving eventual parameter updates,

• providing of typed access methods to parameters towards a user application.

Rationale

No objections or concerns raised yet.

Specification

InternalConfigProviderService passes parameter data as json string to satisfy Config provider interface (feat_req__config_mgmt__provider_interface).

ConfigProvider library translates such a json string in a typed parameter accessible by its name from user application according to Parameter Set access (feat_req__config_mgmt__parameter_set_access).

InternalConfigProviderService makes the usage of methods, events and fields. For instance

• method GetParameterSet { in { String parameter_set_name } out { String parameter_set } } returns a parameter set in JSON representation in terms of Parameter Set access (feat_req__config_mgmt__parameter_set_access)

• attribute InitialQualifierState InitialQualifierState readonly field provides qualifier state in terms of Parameter initial qualifier (feat_req__config_mgmt__prm_initial_qualifier)

• broadcast LastUpdatedParameterSet { out { ParameterSetName last_updated_parameter_set } } event notifies users in case a parameter set has been changed (updated) according to Parameter modification (feat_req__config_mgmt__parameter_modification).

LoLa can be used for IPC communication as soon as methods get supported.

ConfigDaemon uses the file system via json library to write and read files which contain parameters.

Plugin infrastructure may have further dependencies, like SOVD for Coding or persistent key-value storage.

Backwards Compatibility

No compatibility requirements imposed yet.

Security Impact

ConfigDaemon requires secpol abilities for IPC communication and file system accesses.

Further specific mitigations shall be implemented by plugins depending on a kind of parameter.

Safety Impact

Safety related parameters shall be protected by specific integrity checks. Their result will be indicated towards user applications according to Parameter Set qualifier (feat_req__config_mgmt__prm_set_qualifier) and Parameter initial qualifier (feat_req__config_mgmt__prm_initial_qualifier).

A safety related user application is assumed to consider a parameter as unsafe if belonging qualifier is not in a Qualified state.

This feature is rated with ASIL B.

License Impact

[How could the copyright impacted by the license of the new contribution?]

How to Teach This

Rejected Ideas

No ideas rejected yet.

Open Issues

No open issues identified yet.

Footnotes