System Architecture

The PeripheralAdmin service maintains a list of Peripheral objects representing physical devices connected to the system. Using the PeripheralAdmin service allows you to have the Java drivers for devices attached to your gateway automatically configured, updated, started or stopped.

PeripheralAdmin Service

The PeripheralAdmin service provides access to and capabilities for management of devices attached to the hardware. On every device (un)plug it is notified by the respective DeviceObserver service. In a list of PeripheralDescriptor objects the PeripheralAdmin service maintains meta-data about known devices that are expected to connect. The PeripheralAdmin uses the SpecificInfoProvider service to get the specific info about a peripheral device that is plugged. The PeripheralAdmin service uses the ConfigAdmin service to set the configurations for plugged devices and their drivers. To track the driver status of a device plugged to the system and to perform operations with this driver ((un)install, update, start, stop), the PeripheralAdmin uses the ElementInfoProvider service. To publish events to the FW when a device or its driver changes its state (see the diagrams and tables below), the PeripheralAdmin makes use of the EventAdmin service.

DeviceObserver Service

To be notified when devices are attached to or detached from your hardware, the PeripheralAdmin service relies on DeviceObserver services. For communication with the PeripheralAdmin, the respective DeviceObserver uses a PeripheralAdminSpi (PeripheralAdmin Service Provider Interface) object. During its initialization the PeripheralAdmin service provides a PeripheralAdminSpi object to all available DeviceObserver services. Different implementations of the DeviceObserver service interface are used for the different interconnect interfaces (e.g. USB, UPnP, eSATA, PCMCIA, Printer Ports, etc.). Currently, DeviceObserver implementations are available for USB and UPnP devices.

PeripheralDescriptor

In a list of PeripheralDescriptor objects the PeripheralAdmin service maintains meta-data about known devices that are expected to connect. Each PeripheralDescriptor object is associated with a real device and contains data such as:

• the configuration identifier within the ConfiguarationAdmin (PID or Factory PID)
• the properties (name, type, vendor, version, model) that the PeripheralAdmin service sets to the Peripheral object, that represents the plugged peripheral device
• the information about the Peripheral's OSGi driver and its configuration
• the names of the specific properties for the device (e.g. the COM port for a device with a serial interface)
• the properties which values need to match those of a plugged peripheral device in order to associate the device with this PeripheralDescriptor object

For more information about the Peripheral Descriptor structure refer to: Peripheral Descriptor Structure

SpecificInfoProvider Service

The PeripheralAdmin uses the SpecificInfoProvider service to get the specific info about a peripheral device that is plugged, e.g. the COM port to which the device is attached. For the different operating systems platforms different SpecificInfoProvider implementations are used.

DriverInstaller Service

The DriverInstaller service extends the ElementInfoProvider service with the functionality to perform driver (un)install, update, start, stop. Also here different DriverInstaller implementations are used for the different operating systems platforms. The default DriverInstaller implementation (peripheral.driver.installer.noagent, which is used in the target image of the product) after a plugged peripheral device is matched with a descriptor it sends information to the PeripheralAdmin about the state of the required driver to be configured by the PeripheralAdmin.

The PeripheralAdmin Workflow

A typical flow of events after plugging a device:

1. A device is attached (plugged) - > the implementation of the DeviceObserver service corresponding to the interconnect interface of the device notifies the PeripheralAdmin.
2. The PeripheralAdmin tries to match the plugged device with one of the descriptors available.
3. The PeripheralAdmin requests from the SpecificInfoProvider the names of the specific properties for the device plugged.
4. The PeripheralAdmin requests from the ElementInfoProvider service the DriverInfo.
5. If the required driver for the plugged device is installed the PeripheralAdmin sets the configuration for the device and its driver. Otherwise the device cannot be used.
6. A device is un-plugged - > the implementation of the DeviceObserver service corresponding to the interconnect interface of the device notifies the PeripheralAdmin.
7. The PeripheralAdmin removes this device from its list of available devices. If the peripheral.driver.uninstall.auto system property is set to "true", the PeripheralAdmin schedules a task for uninstalling the driver for this device. Depending on the value of the peripheral.driver.uninstall.delay.minutes system property, the driver can be uninstalled with a specific delay after the device is removed.

Device States

Device Driver States

When a peripheral device is plugged the initial state of the device is NOT_ASSOCIATED and the initial state of its driver is NOT_INITIALIZED.

Module Design