diff -r 578be2adaf3e -r 307f4279f433 Adaptation/GUID-6DE69F29-45B0-5E62-AA13-DA4041B1BC46.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Adaptation/GUID-6DE69F29-45B0-5E62-AA13-DA4041B1BC46.dita Fri Oct 15 14:32:18 2010 +0100 @@ -0,0 +1,99 @@ + + + + + +Factory +ImplementationDescribes how to implement a factory. +

The Serial Port Driver PDD must provide a factory class to create channels. +The purpose of the PDD factory is to create the physical channel. For the +Uart, this is defined by the DDriverComm class, which is +derived from DPhysicalDevice. The class is defined in the +Uart source code:

+class DDriverComm : public DPhysicalDevice + { +public: + DDriverComm(); + virtual TInt Install(); + virtual void GetCaps(TDes8 &aDes) const; + virtual TInt Create(DBase*& aChannel, TInt aUnit, const TDesC8* anInfo, const TVersion &aVer); + virtual TInt Validate(TInt aUnit, const TDesC8* anInfo, const TVersion &aVer); + }; + +

This implements the four virtual functions that the base class defines, +as well as a default constructor.

+
Install()

Install() sets +the driver name. The name is the way that the physical device is identified. +The name is the same as the LDD name, but followed by a dot and a short string +to represent the physical device. If you have similar existing source, just +copy from there. The function is implemented as:

TInt DDriverComm::Install() + { + return SetName(&KPddName); + } +

In the template port, the name is the string Comm.Template.

See +also DPhysicalDevice::Install()

+
GetCaps()

GetCaps() returns +the capabilities of the physical driver factory (not the driver object). +Since driver factories all produce polymorphic objects there is no point in +differentiating between them so the function should ignore the passed in descriptor +reference. The driver object’s capabilities are returned by the DComm derived Caps() function.

GetCaps() +can be implemented as a stub function, i.e.:

Void DDriverComm::GetCaps(TDes8& /* aDes */) + { + }

See also DPhysicalDevice::GetCaps()

+
Validate()

Validate() verifies +that the physical driver version is compatible with the caller’s version. +This function can be copied in its entirety from any current driver source. +It also checks that the unit number used to create a physical channel object +is valid, typically checking that the number lies within a valid range.

TInt DDriverComm::Validate(TInt aUnit, const TDesC8* /*anInfo*/, const TVersion& aVer) + { + if ( + (!Kern::QueryVersionSupported(iVersion,aVer)) || + (!Kern::QueryVersionSupported(aVer,TVersion(KMinimumLddMajorVersion,KMinimumLddMinorVersion,KMinimumLddBuild))) + ) + return KErrNotSupported; + if (aUnit<UART_UNIT_OFFSET || aUnit>=(UART_TOTAL_NUMBER_UNITS+UART_UNIT_OFFSET)) + return KErrNotSupported; + return KErrNone; + } +

Note that iVersion is a data member in the +base class DPhysicalDevice.

See also:

    +

  • DPhysicalDevice::Validate()

    • +

  • Kern::QueryVersionSupported()

    • +
+
Create()

Create() creates +and returns a pointer to the physical channel object through the DBase *& +type argument. In the case of serial device drivers, a physical channel is +an instance of a class derived from DComm, which is itself +derived from DBase.

Implementing this function +may involve:

    +

  • setting up any port +related hardware; for example, defining GPIO pins as UART port I/O

    • +

  • initialising the UART +device itself; for example, enabling UART clock sources

    • +

  • binding any interrupt +resources to the UART Interrupt Service Routine (ISR).

    • +

The function sets a reference argument to point to the newly instantiated +physical channel object, but returns an error code if object allocation or +initialisation fails, i.e. the call to the physical channel object’s DoCreate() function +fails. Error codes are returned to the caller.

This code is typical, +and can be copied from any current source.

TInt DDriverComm::Create(DBase*& aChannel, TInt aUnit, const TDesC8* anInfo, const TVersion& aVer) + { + DCommXXX* pD=new DCommXXX; + aChannel=pD; + TInt r=KErrNoMemory; + if (pD) + r=pD->DoCreate(aUnit,anInfo); + return r; + } +

where DCommXXX is a DComm derived +class.

Customisation depends on the functions in the DCommXXX::DoCreate() function.

+ +Interrupt +Dispatcher Tutorial + \ No newline at end of file