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Element: SharedDataDescription

Document type

SharedDataDescription

Document XPath

/SharedDataDescription

Schema XPath

/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription

Description

The SharedDataDescription element is the root element of a SharedDataDescription document that defines the configuration of the shared data region.

You create SharedDataDescription document as a file with SharedDataDescription as its root element. You include the shared data configuration file into your system configuration using an xi:include element in the SharedData element. Optionally, you can include the shared data description inline in the SharedData element.

When creating a SharedDataDescription document as a separate file, you should begin with an XML declaration:

<?xml version="1.0" encoding="UTF-8"?>
			

Following the XML declaration, insert the SharedDataDescription element:

<SharedDataDescription
 xmlns="http://www.windriver.com/vxWorks653/ConfigRecord"
 xmlns:xi="http://www.w3.org/2001/XInclude"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.windriver.com/vxWorks653/ConfigRecord ../cleanschema/Application.xsd">
 VirtualAddress="0x50001000"
 SystemAccess="READ_ONLY"
 DataType="DATABASE"
 CachePolicy="DEFAULT"
 Size="0x00001000">
</SharedDataDescription>
 

The SharedDataDescription element must include the required XML attributes that identify the schema and namespace for the document. The first three attributes are standard and should be entered exactly as shown. The xsi:schemaLocation attribute associates the namespace (http://www.windriver.com/vxWorks653/ConfigRecord) with the schema file (Application.xsd). You should provide the correct path to your copy of the schema. The location of the schema files in the install is installDir/vxworks653-2.2/target/config/xml/cleanschema.

If you use a schema-aware XML editor to create your files, it will probably create these attributes for you.

The other attributes shown are part of the SharedDataDescription element. They are described below.

Use

Required

Children

Extensions

Attributes

CachePolicy

DataType

Size

SystemAccess

VirtualAddress

Restrictions

None

Attribute: CachePolicy

Document XPath
/SharedDataDescription/@CachePolicy
Schema XPath
/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription/@CachePolicy
Description

The caching policy for the shared data region. A setting of DEFAULT is usually, but not always, safe. Consult the BSP documentation, or the person who created the BSP, to determine the appropriate value.

Use

Optional

Target location

ConfigRecord

XML data type

CachePolicyType

Destination data type

Unsigned 32 bit integer

Behavior if not specified

A value of DEFAULT is used.

Values with special meanings

None

Restrictions

None

Attribute: DataType

Document XPath
/SharedDataDescription/@DataType
Schema XPath
/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription/@DataType
Description

The type of data contained in the shared data region. This is used to determine whether the boot loader will load the object file for the shared data region onto the target.

Use

Optional

Target location

None

XML data type

DataRegionType

Destination data type

N/A

Behavior if not specified

The shared data object file will not be loaded.

Values with special meanings

CONFIG_FILE: The shared data object file will be loaded.

DATABASE: The shared data object file will be loaded.

VIRTUAL: The shared data object file will not be loaded.

Restrictions

None

Attribute: Size

Document XPath
/SharedDataDescription/@Size
Schema XPath
/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription/@Size
Description

The size (in bytes) of the shared data region.

To minimize the impact of change on the configuration and certification on the shared data region and the module as a whole, you should size the shared data region to accommodate the largest reasonably foreseeable size of the shared data, rather than setting it to the minimum size required to accommodate the current shared data.

If you increase the size of the shared data region, you may also have to change the values of the following settings to accommodate the increased size of the shared data:

Use

Required

Target location

ConfigRecord

XML data type

DecOrHexValueType

Destination data type

Unsigned 32 bit integer

Behavior if not specified

N/A

Values with special meanings

None

Restrictions

Attribute: SystemAccess

Document XPath
/SharedDataDescription/@SystemAccess
Schema XPath
/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription/@SystemAccess
Description

Determines whether the core OS has the right to access the shared data region.

The right of partitions to access a shared data region are configured using /ConfigRecord/Module/Partitions/Partition/PartitionDescription/SharedDataRegion. Note that the values of this attribute may be interpreted differently, or may not all be supported, on different target architectures. See your hardware documentation to determine what is supported on your target.

Use

Optional

Target location

ConfigRecord

XML data type

UserAccessRightsType

Destination data type

Signed 32 bit integer

Behavior if not specified

The core OS has read and write access to the region.

Values with special meanings

NONE: The core OS has no access to the region.

READ_ONLY: The core OS has read-only access to the region.

READ_WRITE: The core OS has read and write access to the region.

WRITE_ONLY: The core OS has write-only access to the region.

Restrictions

Attribute: VirtualAddress

Document XPath
/SharedDataDescription/@VirtualAddress
Schema XPath
/ConfigRecord/Module/SharedDataRegions/SharedData/SharedDataDescription/@VirtualAddress
Description

The virtual address of the shared data region.

To calculate a suitable virtual address for a shared data region, use the following procedure:

  1. Construct a Module XML document that lists each of your SharedDataDescription documents via a xi:include element. This does not need to be a complete Module document and does not need to conform to the Module document type, as long as the XPath location of the xi:include elements is correct.
  2. From each SharedDataDescription documents completely remove the from the SharedDataDescription file. (You must remove the entire attribute, not merely its value).
  3. For the first library, call the XMLGen tool with the virtaddr option: xmlgen --virtaddr module.xml my-sd (where "module.xml" is the name of the Module file that you created for this purpose, and "my-sd" is the name of the shared data region as expressed by /Module/SharedDataRegions/SharedData/@Name.
  4. For the first SharedDataDescription document, restore the the and give it the value generated by the XMLGen tool.
  5. Repeat for each SharedDataDescription document, making sure that the virtual address of the previous shared data region had be entered into its SharedDataDescription document. (The addresses of the other libraries are needed to calculate a correct address for the current shared data region.)
Use

Optional

Target location

ConfigRecord

XML data type

DecOrHexValueType

Destination data type

Unsigned 32 bit integer

Behavior if not specified

The address is assigned at runtime.

Values with special meanings

0: The address is assigned at runtime.

Restrictions



Generated on 2007-10-15 17:17:22.