commsfwutils/commsbufs/reference/loopback_driver/pdd.cpp
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     1 // Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     2 // All rights reserved.
       
     3 // This component and the accompanying materials are made available
       
     4 // under the terms of "Eclipse Public License v1.0"
       
     5 // which accompanies this distribution, and is available
       
     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     7 //
       
     8 // Initial Contributors:
       
     9 // Nokia Corporation - initial contribution.
       
    10 //
       
    11 // Contributors:
       
    12 //
       
    13 // Description:
       
    14 //
       
    15 
       
    16 #include <kernel/kern_priv.h>
       
    17 
       
    18 #ifdef SYMBIAN_OLD_EXPORT_LOCATION
       
    19 #include <comms-infras/legacy_loopback_driver.h>
       
    20 #else
       
    21 //this header is not exported, needs to be a user include
       
    22 #include "legacy_loopback_driver.h"
       
    23 #endif
       
    24 
       
    25 #include "device.h"
       
    26 
       
    27 // Name for PDD, must match LDD name with a '.' and distinguishing name appended
       
    28 _LIT(KLegacyLoopbackPddName,"legacy_loopback.pdd");
       
    29 
       
    30 
       
    31 typedef TBuf8<KLoopbackMTU> TMTUBuffer;
       
    32 
       
    33 class TQueue
       
    34 	{
       
    35 public:
       
    36 	TMTUBuffer* HeadBuffer() {return &iQueue[iQueueHead];}
       
    37 	TMTUBuffer* TailBuffer() {return &iQueue[iQueueTail];}
       
    38 	
       
    39 	TBool IsEmpty() const {return iLength == 0;}
       
    40 	TBool IsFull() const {return iLength == KLoopbackQueueLen;}
       
    41 	TInt MaxLength() const {return KLoopbackQueueLen;}
       
    42 	TInt Length() const {return iLength;}
       
    43 
       
    44 	void Pop()
       
    45 		{
       
    46 		__ASSERT_ALWAYS(iLength > 0, Kern::Fault("comms loopback", KErrOverflow));
       
    47 		iQueueHead++;
       
    48 		if(iQueueHead == KLoopbackQueueLen)
       
    49 			{
       
    50 			iQueueHead = 0;
       
    51 			}
       
    52 		iLength--;
       
    53 		}
       
    54 
       
    55 	void Push()
       
    56 		{
       
    57 		__ASSERT_ALWAYS(iLength < KLoopbackQueueLen, Kern::Fault("comms loopback", KErrOverflow));
       
    58 		iQueueTail++;
       
    59 		if(iQueueTail == KLoopbackQueueLen)
       
    60 			{
       
    61 			iQueueTail = 0;
       
    62 			}
       
    63 		iLength++;
       
    64 		}
       
    65 
       
    66 	TQueue() : iQueueHead(0), iQueueTail(0), iLength(0) {}
       
    67 
       
    68 private:
       
    69 	TMTUBuffer iQueue[KLoopbackQueueLen];
       
    70 	TInt iQueueHead;
       
    71 	TInt iQueueTail;
       
    72 	TInt iLength;
       
    73 	};
       
    74 
       
    75 
       
    76 class DESockLoopbackDevice : public DESockLoopback
       
    77 	{
       
    78 public:
       
    79 	DESockLoopbackDevice(DESockLoopbackPddFactory* aFactory);
       
    80 	~DESockLoopbackDevice();
       
    81 	TInt DoCreate();
       
    82 	// Inherited from DESockLoopback. These called by the LDD.
       
    83 	virtual TInt BufferSize() const;
       
    84 	virtual TInt Speed() const;
       
    85 	virtual TInt SetSpeed(TInt aSpeed);
       
    86 	virtual TInt RequestDataSend();
       
    87 	virtual void SendDataCancel();
       
    88 	virtual TInt RequestDataReceipt();
       
    89 	virtual void ReceiveDataCancel();
       
    90 	virtual TDes8& SendBuffer();
       
    91 	virtual TDesC8& ReceiveBuffer();
       
    92 	virtual TBool ReceivedQueueLen();
       
    93 	virtual void AdvanceReceiveQueue();
       
    94 
       
    95 private:
       
    96 	void SendDataCallback();
       
    97 	void ReceiveDataCallback();
       
    98 	
       
    99 	static void DataRecvCallback(TAny* aSelf);
       
   100 	void DoDataRecvCallback();
       
   101 private:
       
   102 	DESockLoopbackPddFactory* iFactory;
       
   103 	TInt iSpeed;
       
   104 
       
   105 	TQueue iSendQueue;
       
   106 	TQueue iReceiveQueue;
       
   107 
       
   108 	TBool iPendingRead;
       
   109 	TDfc iRecvDataDfc;
       
   110 	};
       
   111 
       
   112 
       
   113 
       
   114 const TInt KESockLoopbackThreadPriority = 27;
       
   115 _LIT(KESockLoopbackThread,"ESockLoopbackThread");
       
   116 
       
   117 /**
       
   118   Standard export function for PDDs. This creates a DPhysicalDevice derived object,
       
   119   in this case, our DESockLoopbackPddFactory
       
   120 */
       
   121 DECLARE_STANDARD_PDD()
       
   122 	{
       
   123 	return new DESockLoopbackPddFactory;
       
   124 	}
       
   125 
       
   126 DESockLoopbackPddFactory::DESockLoopbackPddFactory()
       
   127 	{
       
   128 	// Set version number for this device
       
   129 	iVersion=RLegacyLoopbackDriver::VersionRequired();
       
   130 	}
       
   131 
       
   132 /**
       
   133   Second stage constructor for DPhysicalDevice derived objects.
       
   134   This must at least set a name for the driver object.
       
   135 
       
   136   @return KErrNone or standard error code.
       
   137 */
       
   138 TInt DESockLoopbackPddFactory::Install()
       
   139 	{
       
   140 	// Allocate a kernel thread to run the DFC 
       
   141 	TInt r = Kern::DynamicDfcQCreate(iDfcQ, KESockLoopbackThreadPriority, KESockLoopbackThread);
       
   142 	if (r == KErrNone)
       
   143 		{ 
       
   144 		r = SetName(&KLegacyLoopbackPddName);
       
   145 		} 	
       
   146 	return r;
       
   147 	}
       
   148 
       
   149 /**
       
   150   Returns the drivers capabilities. This is not used by the Symbian OS device driver framework
       
   151   but may be useful for the LDD to use.
       
   152 
       
   153   @param aDes Descriptor to write capabilities information into
       
   154 */
       
   155 void DESockLoopbackPddFactory::GetCaps(TDes8& aDes) const
       
   156 	{
       
   157 	// Create a capabilities object
       
   158 	DESockLoopback::TCaps caps;
       
   159 	caps.iVersion = iVersion;
       
   160 	// Zero the buffer
       
   161 	TInt maxLen = aDes.MaxLength();
       
   162 	aDes.FillZ(maxLen);
       
   163 	// Copy cpabilities
       
   164 	TInt size=sizeof(caps);
       
   165 	if(size>maxLen)
       
   166 		size=maxLen;
       
   167 	aDes.Copy((TUint8*)&caps,size);
       
   168 	}
       
   169 
       
   170 /**
       
   171   Called by the kernel's device driver framework to create a Physical Channel.
       
   172   This is called in the context of the user thread (client) which requested the creation of a Logical Channel
       
   173   (E.g. through a call to RBusLogicalChannel::DoCreate)
       
   174   The thread is in a critical section.
       
   175 
       
   176   @param aChannel Set to point to the created Physical Channel
       
   177   @param aUnit The unit argument supplied by the client to RBusLogicalChannel::DoCreate
       
   178   @param aInfo The info argument supplied by the client to RBusLogicalChannel::DoCreate
       
   179   @param aVer The version number of the Logical Channel which will use this Physical Channel 
       
   180 
       
   181   @return KErrNone or standard error code.
       
   182 */
       
   183 TInt DESockLoopbackPddFactory::Create(DBase*& aChannel, TInt aUnit, const TDesC8* aInfo, const TVersion& aVer)
       
   184 	{
       
   185 	// Ignore the parameters we aren't interested in...
       
   186 	(void)aUnit;
       
   187 	(void)aInfo;
       
   188 	(void)aVer;
       
   189 
       
   190 	// Create a new physical channel
       
   191 	DESockLoopbackDevice* device=new DESockLoopbackDevice(this);
       
   192 	aChannel=device;
       
   193 	if (!device)
       
   194 		return KErrNoMemory;
       
   195 	return device->DoCreate();
       
   196 	}
       
   197 
       
   198 /**
       
   199   Called by the kernel's device driver framework to check if this PDD is suitable for use with a Logical Channel.
       
   200   This is called in the context of the user thread (client) which requested the creation of a Logical Channel
       
   201   (E.g. through a call to RBusLogicalChannel::DoCreate)
       
   202   The thread is in a critical section.
       
   203 
       
   204   @param aUnit The unit argument supplied by the client to RBusLogicalChannel::DoCreate
       
   205   @param aInfo The info argument supplied by the client to RBusLogicalChannel::DoCreate
       
   206   @param aVer The version number of the Logical Channel which will use this Physical Channel 
       
   207 
       
   208   @return KErrNone or standard error code.
       
   209 */
       
   210 TInt DESockLoopbackPddFactory::Validate(TInt aUnit, const TDesC8* aInfo, const TVersion& aVer)
       
   211 	{
       
   212 	// Check version numbers
       
   213 	if ((!Kern::QueryVersionSupported(iVersion,aVer)) || (!Kern::QueryVersionSupported(aVer,TVersion(EMinimumLddMajorVersion,EMinimumLddMinorVersion,EMinimumLddBuild))))
       
   214 		return KErrNotSupported;
       
   215 
       
   216 	// We don't support units
       
   217     if (aUnit != -1)
       
   218         return KErrNotSupported;
       
   219 
       
   220 	// Ignore extra info, (this could be used for validation purposes)
       
   221 	// Note, aInof is a pointer to a descriptor in user memory, therefore safe methods should
       
   222 	// be used for reading its contents. E.g. using Kern::KUDesGet()
       
   223 	(void)aInfo;
       
   224 
       
   225 	// OK
       
   226 	return KErrNone;
       
   227 	}
       
   228 
       
   229 DESockLoopbackPddFactory::~DESockLoopbackPddFactory()
       
   230 	{
       
   231 	if (iDfcQ)
       
   232 		iDfcQ->Destroy();
       
   233 	}
       
   234 
       
   235 DESockLoopbackDevice::DESockLoopbackDevice(DESockLoopbackPddFactory* aFactory)
       
   236 	:	iFactory(aFactory),
       
   237 		iSpeed(100000),  // 100000us (100ms) per byte
       
   238 		iSendQueue(),
       
   239 		iReceiveQueue(),
       
   240 		iRecvDataDfc(DataRecvCallback, this, aFactory->iDfcQ, 1)
       
   241 
       
   242 	{
       
   243 	}
       
   244 
       
   245 DESockLoopbackDevice::~DESockLoopbackDevice()
       
   246 	{
       
   247 	// Driver no longer using hardware resources
       
   248 	NKern::LockedDec(iFactory->iHardwareInUse);
       
   249 	}
       
   250 
       
   251 TInt DESockLoopbackDevice::DoCreate()
       
   252 	{
       
   253 	// Claim the hardware resources by incrementing iHardwareInUse.
       
   254 	// Must do this before any other failure can happen in this function so that
       
   255 	// the destructor can safely decrement iHardwareInUse.
       
   256 	//
       
   257 	// This method of ensuring hardware is only in use by one driver at a time
       
   258 	// wouldn't be needed if the driver claimed real hardware resources which
       
   259 	// could only be used once. E.g. binding to an interrupt.
       
   260 	if(NKern::LockedInc(iFactory->iHardwareInUse))
       
   261 		return KErrInUse;
       
   262 
       
   263 	// Other setup goes here
       
   264 
       
   265 	return KErrNone;
       
   266 	}
       
   267 
       
   268 TInt DESockLoopbackDevice::BufferSize() const
       
   269 	{
       
   270 	return iSendQueue.MaxLength();
       
   271 	}
       
   272 
       
   273 TInt DESockLoopbackDevice::Speed() const
       
   274 	{
       
   275 	return iSpeed;
       
   276 	}
       
   277 
       
   278 TInt DESockLoopbackDevice::SetSpeed(TInt aSpeed)
       
   279 	{
       
   280 	if(aSpeed<=0)
       
   281 		return KErrArgument;
       
   282 	iSpeed = aSpeed;
       
   283 	return KErrNone;
       
   284 	}
       
   285 
       
   286 TInt DESockLoopbackDevice::RequestDataSend()
       
   287 	{
       
   288 	// Push our send buffer in to the queue
       
   289 	iSendQueue.Push();
       
   290 	
       
   291 	// Trigger reception
       
   292 	NKern::Lock(); 
       
   293 	SendDataCallback();
       
   294 	NKern::Unlock(); 
       
   295 	
       
   296 	return KErrNone;
       
   297 	}
       
   298 
       
   299 void DESockLoopbackDevice::SendDataCancel()
       
   300 	{
       
   301 	}
       
   302 
       
   303 void DESockLoopbackDevice::SendDataCallback()
       
   304 	{
       
   305 	// Tell self new data is coming
       
   306 	iRecvDataDfc.Add();
       
   307 
       
   308 	// Tell LDD we've done sending
       
   309 	iLdd->SendDataComplete(KErrNone);
       
   310 	}
       
   311 
       
   312 TInt DESockLoopbackDevice::RequestDataReceipt()
       
   313 	{
       
   314 	iPendingRead = ETrue;
       
   315 	if(!(iReceiveQueue.IsEmpty() && iSendQueue.IsEmpty()))
       
   316 		{
       
   317 		NKern::Lock(); 
       
   318 		ReceiveDataCallback();
       
   319 		NKern::Unlock(); 
       
   320 		}
       
   321 	return KErrNone;
       
   322 	}
       
   323 
       
   324 void DESockLoopbackDevice::ReceiveDataCancel()
       
   325 	{
       
   326 	}
       
   327 
       
   328 void DESockLoopbackDevice::ReceiveDataCallback()
       
   329 	{
       
   330 	// Copy buffer from send queue (it's like our receive hardware) to receive queue
       
   331 	if(!iReceiveQueue.IsFull() && !iSendQueue.IsEmpty())
       
   332 		{
       
   333 		// Copy the buffer from one queue to the other and patch up descriptor
       
   334 		TDes8* srcDesc = iSendQueue.HeadBuffer();
       
   335 		TDes8* destDesc = iReceiveQueue.TailBuffer();
       
   336 
       
   337 		const TUint8* srcPtr = srcDesc->Ptr();
       
   338 		const TUint8* destPtr = destDesc->Ptr();
       
   339 
       
   340 		TInt length = srcDesc->Length();
       
   341 
       
   342 		memcpy((void*)destPtr, (void*)srcPtr, length);
       
   343 
       
   344 		destDesc->SetLength(length);
       
   345 		
       
   346 		// Bump the receive queue now that we have loaded it
       
   347 		iReceiveQueue.Push();
       
   348 	
       
   349 		// Drop our incoming buffer
       
   350 		iSendQueue.Pop();
       
   351 
       
   352 		// If there is a pending read request then we can now satisfy it
       
   353 		if(iPendingRead)
       
   354 			{
       
   355 			iPendingRead = FALSE;
       
   356 
       
   357 			// Tell LDD we're done
       
   358 			iLdd->ReceiveDataComplete(KErrNone);
       
   359 			}
       
   360 		}
       
   361 	}
       
   362 
       
   363 TDes8& DESockLoopbackDevice::SendBuffer()
       
   364 	{
       
   365 	return *iSendQueue.TailBuffer();
       
   366 	}
       
   367 
       
   368 TDesC8& DESockLoopbackDevice::ReceiveBuffer()
       
   369 	{
       
   370 	return *iReceiveQueue.HeadBuffer();
       
   371 	}
       
   372 
       
   373 void DESockLoopbackDevice::AdvanceReceiveQueue()
       
   374 	{
       
   375 	iReceiveQueue.Pop();
       
   376 	}
       
   377 
       
   378 TInt DESockLoopbackDevice::ReceivedQueueLen()
       
   379 	{
       
   380 	return iReceiveQueue.Length();
       
   381 	}
       
   382 
       
   383 
       
   384 void DESockLoopbackDevice::DataRecvCallback(TAny* aSelf)
       
   385 	{
       
   386 	((DESockLoopbackDevice*)aSelf)->ReceiveDataCallback();
       
   387 	}