// Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

 // All rights reserved.

 // This component and the accompanying materials are made available

 // under the terms of "Eclipse Public License v1.0"

 // which accompanies this distribution, and is available

 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

 //

 // Initial Contributors:

 // Nokia Corporation - initial contribution.

 //

 // Contributors:

 //

 // Description:

 // include/drivers/dma_hai.h

 // DMA Framework - Symbian Hardware Abstraction Interface (SHAI).

 //

 //

 #ifndef __DMA_HAI_H__

 #define __DMA_HAI_H__

 #include <kernel/kern_priv.h>

 //////////////////////////////////////////////////////////////////////////////

 /** Interface used by PIL to open and close DMA channels.

 	Must be implemented by the PSL.

 	@publishedPartner

 	@released

 */

 class DmaChannelMgr

 	{

 public:

 	/** Opens a channel using a client-provided identifier.

 		This function must be implemented by the PSL.

 		@param aOpenId PSL-specific magic cookie passed by client. This could

 		identify the channel exactly (by being just the channel number), or at

 		least sufficiently (for example for use with a certain peripheral), or

 		it may indicate some properties which the channel must possess. It may

 		be set to zero always if all channels are equivalent.

 		@param aDynChannel ETrue if the Open call is for a dynamic channel. A

 		dynamic channel is not exclusively reserved for just one client, and

 		further Open calls for more dynamic channels should succeed as long as

 		certain resources (but not including the number of available physical

 		channels) are not exceeded. Different transfer requests on this dynamic

 		channel may be serviced using different actual channels.

 		@param aPriority The desired channel priority as requested by the

 		client. This may be an actual hardware priority or a

 		platform-independent value. Not being able to satisfy the requested

 		value is not a reason for the PSL to return NULL. This parameter may be

 		ignored if aDynChannel is passed as ETrue. An overriding per-transfer

 		priority may be requested by a client later via

 		TDmaTransferArgs::iChannelPriority.

 		@see SDmacCaps::iChannelPriorities

 		@see TDmaPriority

 		@return Pointer to channel if available, NULL otherwise. It should not

 		be NULL if the Open call was for a dynamic channel unless a processing

 		error occurred.

 		@pre The PIL calls this function with a global fast mutex held to avoid

 		race conditions.

 		@post If a non-NULL pointer is returned, the object pointed to has its

 		iController, iDmacCaps, iPslId, iDynChannel and iPriority members set

 		to valid states.

 		iController should point to the controller handling the

 		channel.

 		iDmacCaps should point to a SDmacCaps structure containing values

 		relating to this particular channel.

 		iPslId should contain a value uniquely identifying the channel - the

 		PIL assigns this value later during request fragmentation to

 		TDmaTransferArgs::iChannelCookie. It can be given any convenient value

 		by the PSL (channel index, I/O port address, etc.).

 		iDynChannel should be set to ETrue by the PSL if a dynamic channel was

 		requested and has been opened.

 		If applicable, iPriority should contain the actual hardware priority

 		that has been configured or reserved. Otherwise it may be left at its

 		default value TDmaPriority::KDmaPriorityNone.

 	*/

 	static TDmaChannel* Open(TUint32 aOpenId, TBool aDynChannel, TUint aPriority);

 	/** Performs platform-specific operations when a channel is closed.

 		If aChannel was opened as a dynamic channel then this call is a sign

 		that there is a client which does not intend to queue any further

 		transfer requests via this channel.

 		This function must be implemented by the PSL but the implementation can

 		be a no-op.

 		@param aChannel The channel to close

 		@pre The PIL calls this function with a global fast mutex held to avoid

 		race conditions.

 	*/

 	static void Close(TDmaChannel* aChannel);

 	/** Function allowing PSL to extend DMA API with new channel-independent

 		operations.

 		This function must be implemented by the PSL.

 		@param aCmd Command identifier. Negative values are reserved for FW

 		internal use.

 		@param aArg PSL-specific

 		@return KErrNotSupported if aCmd is not supported. PSL-specific value

 		otherwise.

 	 */

 	static TInt StaticExtension(TInt aCmd, TAny* aArg);

 	/** Acquires the channel manager lock. Called by the PIL before opening and

 		closing a channel.

 	*/

 	static void Wait();

 	/** Releases the channel manager lock. Called by the PIL after opening and

 		closing a channel.

 	*/

 	static void Signal();

 private:

 	/** Declared, defined, and called by PSL's DECLARE_STANDARD_EXTENSION(). */

 	friend TInt InitExtension();

 	/** Must be called in the DMA DLL entry point. */

 	static TInt Initialise();

 	static NFastMutex Lock;

 	};

 //////////////////////////////////////////////////////////////////////////////

 /** Abstract base class representing a DMA controller.

 	The class has two purposes.

 	First, it is a container for channels, descriptors and descriptor headers.

 	Second, it exposes a set of virtual functions implemented by the PSL

 	(platform-specific layer).

 	These functions are the main interfaces between the PIL

 	(platform-independent layer) and PSL.

 	@publishedPartner

 	@released

 */

 class TDmac

 	{

 	friend class DmaChannelMgr;

 protected:

 	/** Data required for creating a new instance */

 	struct SCreateInfo

 		{

 		/** True if DMAC uses hardware descriptors (i.e. supports

 			scatter/gather mode).

 		*/

 		TBool iCapsHwDes;

 		/** Initial maximum number of descriptors and headers (shared by all

 			channels) to be allocated by the PIL. If at run time more

 			descriptors are needed then they will be dynamically allocated and

 			added to the available pool.

 			The PSL may consider a number of factors when providing this

 			initial value, such as the number of channels on this controller,

 			the maximum transfer size per descriptor and also likely usage

 			scenarios for the platform or device (number of drivers using DMA,

 			their traffic patterns, simultaneity of operations, etc.).

 		*/

 		TInt iDesCount;

 		/** Size of individual descriptors. Use sizeof(TDmaTransferArgs) for

 		 	single-buffer and double-buffer (i.e. non-s/g) controllers.

 		*/

 		TInt iDesSize;

 		/** Bitmask used when creating the memory chunk storing the descriptor

 			pool. Used only for hardware descriptors.

 			The access part must be EMapAttrSupRw. If the chunk is cached

 			and/or buffered, the PSL must flush the data cache and/or drain the

 			write buffer in InitHwDes() and related functions.

 			The physical start address of the chunk will always be MMU page

 		 	size aligned.

 		 	@see TMappingAttributes

 		 */

 		TUint iDesChunkAttribs;

 		};

 	/** Base class constructor. */

 	TDmac(const SCreateInfo& aInfo);

 	/** Base class 2nd-phase constructor. */

 	TInt Create(const SCreateInfo& aInfo);

 public:

 	/** Base class virtual destructor. */

 	virtual ~TDmac();

 	/** Allocates a number of headers (and hence also descriptors) from the

 		header/descriptor pools. Called by the PIL but may also be used by the

 		PSL.

 	*/

 	TInt ReserveSetOfDes(TInt aCount);

 	/** Returns previously allocated headers (and hence also descriptors) to

 		the header/descriptor pools. Called by the PIL but may also be used by

 		the PSL.

 	*/

 	void ReleaseSetOfDes(TInt aCount);

 	/** Called by the PIL during request fragmentation to fill a descriptor or

 		pseudo descriptor with transfer arguments.

 	*/

 	TInt InitDes(const SDmaDesHdr& aHdr, const TDmaTransferArgs& aTransferArgs);

 	/** Called by the PIL in TDmaChannel::IsrRedoRequest() if any of the

 		latter's arguments is non-zero.

 	*/

 	TInt UpdateDes(const SDmaDesHdr& aHdr, TUint32 aSrcAddr, TUint32 aDstAddr,

 				   TUint aTransferCount, TUint32 aPslRequestInfo);

 	/** Returns a reference to the associated pseudo descriptor for a given

 		descriptor header. For use by PIL and PSL.

 	*/

 	inline TDmaTransferArgs& HdrToDes(const SDmaDesHdr& aHdr) const;

 	/** Returns a reference to the associated hardware descriptor for a given

 		descriptor header. For use by PIL and PSL.

 	*/

 	inline TAny* HdrToHwDes(const SDmaDesHdr& aHdr) const;

 	/** Returns the physical address of the hardware descriptor

 		pointed to by aDes. For use by PIL and PSL.

 	*/

 	inline TUint32 HwDesLinToPhys(TAny* aDes) const;

 	/** Called by the PIL to acquire the controller lock which protects the

 		header and descriptor pools.

 	*/

 	inline void Wait();

 	/** Called by the PIL to release the controller lock which protects the

 		header and descriptor pools.

 	*/

 	inline void Signal();

 public:

 	/** Called by PIL when one fragment (single-buffer and double-buffer DMACs)

 		or list of fragments (scatter/gather DMAC) is to be transferred.

 		Called when initiating a new transfer and also, for double-buffer

 		DMACs, for configuring the next fragment to transfer while the current

 		one is ongoing.

 		The function must be implemented by the PSL if

 		SCreateInfo::iCaps::iAsymHwDescriptors is reported as false.

 		@note This function may be called in thread or ISR context by the PIL

 		@param aChannel The channel to use.

 		@param aHdr Header associated with fragment to transfer.

 	*/

 	virtual void Transfer(const TDmaChannel& aChannel, const SDmaDesHdr& aHdr);

 	/** Called by PIL when two lists of fragments (scatter/gather DMAC with

 		asymmetrical linked-list capability) are to be transferred.

 		Called when initiating a new transfer.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@note This function may be called in thread or ISR context by the PIL

 		@param aChannel The channel to use.

 		@param aSrcHdr Header associated with descriptor to transfer on the

 		source side.

 		@param aDstHdr Header associated with descriptor to transfer on the

 		destination side.

 	*/

 	virtual void Transfer(const TDmaChannel& aChannel, const SDmaDesHdr& aSrcHdr,

 						  const SDmaDesHdr& aDstHdr);

 	/** Called by PIL to stop a transfer on a given channel.

 		The stopping must occur synchronously as the PIL assumes the channel

 		is halted after calling this function. A channel stopped via this

 		function is not intended to be resumed. Function must always be

 		implemented by the PSL.

 		@param aChannel The channel to stop

 		@post The channel will be idle

 		@post No interrupt will occur from this channel until a new

 		request is queued.

 	*/

 	virtual void StopTransfer(const TDmaChannel& aChannel) = 0;

 	/** Called by PIL to pause (suspend) a transfer on a given channel.

 		A paused channel transfer must be able to be resumed by calling

 		ResumeTransfer().

 		The function must be implemented by the PSL if

 		SDmacCaps::iChannelPauseAndResume is reported as true.

 		@return KErrNone if the transfer has been paused successfully,

 		KErrCompletion if the transfer was already paused, KErrGeneral

 		if a general error occurred preventing a successful outcome.

 		@post No interrupt will occur from this channel until it is

 		resumed.

 	 */

 	virtual TInt PauseTransfer(const TDmaChannel& aChannel);

 	/** Called by PIL to resume a paused (suspended) transfer on a given

 		channel.

 		Resume() can be called when the transfer is paused as a result of a

 		previous call to PauseTransfer() or because the DMAC has encountered a

 		Pause bit in a H/W descriptor.

 		The function must be implemented by the PSL if

 		SDmacCaps::iChannelPauseAndResume is reported as true.

 		@return KErrNone if the transfer has been resumed successfully,

 		KErrCompletion if there was no paused transfer, KErrGeneral

 		if a general error occurred preventing a successful outcome.

 	 */

 	virtual TInt ResumeTransfer(const TDmaChannel& aChannel);

 	/** Called by PIL to check whether a DMA channel is idle.

 		'Idle' here means that the channel is ultimately stopped, for example

 		because the transfer has finished, or an error was encountered, or it

 		was manually stopped, but not because it was manually suspended (aka

 		'paused'), or it is waiting for a request line assertion to start the

 		transfer.

 		@param aChannel The channel to test

 		@return ETrue if channel idle, EFalse if transferring.

 	*/

 	virtual TBool IsIdle(const TDmaChannel& aChannel) = 0;

 	/** Called by PIL to retrieve from the PSL the maximum transfer length

 		based on the parameters passed.

 		@param aChannel Channel to be used for the transfer

 		@param aSrcFlags Bitmask characterising transfer source

 		@see TDmaTransferArgs::iSrcConfig::iFlags

 		@param aDstFlags Bitmask characterising transfer destination

 		@see TDmaTransferArgs::iDstConfig::iFlags

 		@param aPslInfo Cookie passed by client and used by the PSL

 		@see TDmaTransferArgs::iPslRequestInfo

 		@return 0 if transfer length is not limited, the maximum transfer

 		length in bytes otherwise.

 	*/

 	virtual TUint MaxTransferLength(TDmaChannel& aChannel, TUint aSrcFlags,

 									TUint aDstFlags, TUint32 aPslInfo) = 0;

 	/** Called by PIL to retrieve from the PSL the memory alignment mask based

 		on the parameters passed. Some DMA controllers impose alignment

 		constraints on the base address of memory buffers. This mask is AND'ed

 		against memory addresses computed during fragmentation.

 		The PIL will call this function separately for source and destination.

 		An assumption is that the PSL doesn't need to know if a call to this

 		function is for the source or the destination side, i.e. both ports

 		are, as far as the alignment is concerned, equivalent. All that matters

 		are the values of the relevant configuration parameters.

 		Another assumption is that the alignment requirement for a port on a

 		DMAC with potentially different values for source and destination does

 		not depend on the configuration of the respective other port.

 		@param aChannel Channel used for the transfer

 		@param aTargetFlags Bitmask characterising transfer source or

 		destination

 		@see TDmaTransferArgs::iSrcConfig::iFlags

 		@see TDmaTransferArgs::iDstConfig::iFlags

 		@param aElementSize Element size used for the transfer. May be zero if

 		not known or 'don't care'.

 		@param aPslInfo Cookie passed by client and used by the PSL

 		@see TDmaTransferArgs::iPslRequestInfo

 		@return A value representing the alignment mask (e.g. 3 if buffer must

 		be 4-byte aligned)

 	*/

 	virtual TUint AddressAlignMask(TDmaChannel& aChannel, TUint aTargetFlags,

 								   TUint aElementSize, TUint32 aPslInfo) = 0;

 	/** Called by PIL during fragmentation to initialise a hardware descriptor.

 		The PSL must assume the descriptor is the last in the chain and so set

 		the interrupt bit and set the next descriptor field to an end of chain

 		marker.

 		The function must be implemented by the PSL if and only if the DMAC

 		supports hardware descriptors and SDmaCaps::iAsymHwDescriptors is

 		reported as false.

 		@param aHdr Header associated with the hardware descriptor to

 		initialise

 		@param aTransferArgs The transfer parameters for this descriptor

 		@return KErrNone if the descriptor was successfully initialized,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt InitHwDes(const SDmaDesHdr& aHdr, const TDmaTransferArgs& aTransferArgs);

 	/** Called by PIL during fragmentation to initialise a hardware descriptor

 		on the source side of an asymmetric linked list.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@param aHdr Header associated with the hardware descriptor to

 		initialise

 		@param aTransferArgs The transfer parameters for this descriptor. Only

 		the elements relating to the source side should be relevant to the

 		implementation.

 		@return KErrNone if the descriptor was successfully initialized,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt InitSrcHwDes(const SDmaDesHdr& aHdr, const TDmaTransferArgs& aTransferArgs);

 	/** Called by PIL during fragmentation to initialise a hardware descriptor

 		on the destination side of an asymmetric linked list.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@param aHdr Header associated with the hardware descriptor to

 		initialise

 		@param aTransferArgs The transfer parameters for this descriptor. Only

 		the elements relating to the destination side should be relevant to the

 		implementation.

 		@return KErrNone if the descriptor was successfully initialized,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt InitDstHwDes(const SDmaDesHdr& aHdr, const TDmaTransferArgs& aTransferArgs);

 	/** Called by the PIL in ISR context to change specific fields in a

 		hardware descriptor.

 		The function must be implemented by the PSL if and only if the DMAC

 		supports hardware descriptors and SDmaCaps::iAsymHwDescriptors is

 		reported as false.

 		@param aHdr Header associated with the hardware descriptor to be

 		updated

 		@param aSrcAddr @see TDmaTransferArgs::iSrcConfig::iAddr

 		@param aDstAddr @see TDmaTransferArgs::iDstConfig::iAddr

 		@param aTransferCount @see TDmaTransferArgs::iTransferCount

 		@param aPslRequestInfo @see TDmaTransferArgs::iPslRequestInfo

 		Since Epoc::LinearToPhysical() cannot be called in ISR context the

 		addresses passed into this function are always physical ones, i.e.

 		TDmaTransferFlags::KDmaPhysAddr is implied.

 		@return KErrNone if the descriptor was successfully modified,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt UpdateHwDes(const SDmaDesHdr& aHdr, TUint32 aSrcAddr, TUint32 aDstAddr,

 							 TUint aTransferCount, TUint32 aPslRequestInfo);

 	/** Called by the PIL in ISR context to change specific fields in a

 		hardware descriptor.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@param aHdr Header associated with the hardware descriptor to be

 		updated

 		@param aSrcAddr @see TDmaTransferArgs::iSrcConfig::iAddr

 		@param aTransferCount @see TDmaTransferArgs::iTransferCount

 		@param aPslRequestInfo @see TDmaTransferArgs::iPslRequestInfo

 		Since Epoc::LinearToPhysical() cannot be called in ISR context the

 		address passed into this function is always a physical ones, i.e.

 		TDmaTransferFlags::KDmaPhysAddr is implied.

 		@return KErrNone if the descriptor was successfully modified,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt UpdateSrcHwDes(const SDmaDesHdr& aHdr, TUint32 aSrcAddr,

 								TUint aTransferCount, TUint32 aPslRequestInfo);

 	/** Called by the PIL in ISR context to change specific fields in a

 		hardware descriptor.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@param aHdr Header associated with the hardware descriptor to be

 		updated

 		@param aDstAddr @see TDmaTransferArgs::iDstConfig::iAddr

 		@param aTransferCount @see TDmaTransferArgs::iTransferCount

 		@param aPslRequestInfo @see TDmaTransferArgs::iPslRequestInfo

 		Since Epoc::LinearToPhysical() cannot be called in ISR context the

 		address passed into this function is always a physical ones, i.e.

 		TDmaTransferFlags::KDmaPhysAddr is implied.

 		@return KErrNone if the descriptor was successfully modified,

 		KErrArgument if any of the transfer arguments were detected to be

 		invalid, KErrGeneral if a general error occurred preventing a

 		successful outcome.

 	*/

 	virtual TInt UpdateDstHwDes(const SDmaDesHdr& aHdr, TUint32 aDstAddr,

 								TUint aTransferCount, TUint32 aPslRequestInfo);

 	/** Called by PIL, when fragmenting a request, to append a new hardware

 		descriptor to an existing descriptor chain. May also be called by

 		clients who wish to create their own descriptor chains.

 		Must clear the interrupt bit of the descriptor associated with aHdr.

 		The function must be implemented by the PSL if and only if the DMAC

 		supports hardware descriptors.

 		@param aHdr Header associated with last fragment in chain

 		@param aNextHdr Header associated with fragment to append

 	*/

 	virtual void ChainHwDes(const SDmaDesHdr& aHdr, const SDmaDesHdr& aNextHdr);

 	/** Called by PIL when queuing a new request while the channel is running.

 		Must append the first hardware descriptor of the new request to the

 		last descriptor in the existing chain.

 		The function must be implemented by the PSL if and only if the DMAC

 		supports hardware descriptors.

 		@param aChannel The channel where the transfer takes place

 		@param aLastHdr Header associated with last hardware descriptor in

 		chain

 		@param aNewHdr Header associated with first hardware descriptor in new

 		request

 	*/

 	virtual void AppendHwDes(const TDmaChannel& aChannel, const SDmaDesHdr& aLastHdr,

 							 const SDmaDesHdr& aNewHdr);

 	/** Called by PIL when queuing a new request while the channel is running.

 		Must append the first hardware descriptor of the new request to the

 		last descriptor in the existing chain.

 		The function must be implemented by the PSL if

 		SDmaCaps::iAsymHwDescriptors is reported as true.

 		@param aChannel The channel where the transfer takes place

 		@param aSrcLastHdr Header associated with the last descriptor in the

 		source side chain

 		@param aSrcNewHdr Header associated with the first source side

 		descriptor of the new request

 		@param aDstLastHdr Header associated with the last descriptor in the

 		destination side chain

 		@param aDstNewHdr Header associated with the first destination side

 		descriptor of the new request

 	*/

 	virtual void AppendHwDes(const TDmaChannel& aChannel,

 							 const SDmaDesHdr& aSrcLastHdr, const SDmaDesHdr& aSrcNewHdr,

 							 const SDmaDesHdr& aDstLastHdr, const SDmaDesHdr& aDstNewHdr);

 	/** Called by PIL when completing or cancelling a request to cause the PSL

 		to unlink the last item in the h/w descriptor chain from a subsequent

 		chain that it was possibly linked to.

 		The function must be implemented by the PSL if and only if the DMAC

 		supports hardware descriptors.

 		@param aChannel The channel where the request (and thus the descriptor)

 		was queued

 		@param aHdr Header associated with last h/w descriptor in

 		completed / cancelled chain

 	*/

 	virtual void UnlinkHwDes(const TDmaChannel& aChannel, SDmaDesHdr& aHdr);

 	/** Called by PIL when freeing descriptors back to the shared pool in

 		FreeDesList(). The PSL inside ClearHwDes() can clear the contents of

 		the h/w descriptor.

 		This may be necessary if the PSL implementation uses the h/w descriptor

 		as another header which in turn points to the actual DMA h/w descriptor

 		(aka LLI).

 		The function may be implemented by the PSL if the DMAC supports

 		hardware descriptors.

 		@param aHdr Header associated with the h/w descriptor being freed.

 	 */

 	virtual void ClearHwDes(const SDmaDesHdr& aHdr);

 	/** Called by PIL to logically link two physical channels.

 		The function must be implemented by the PSL if the DMAC supports

 		logical channel linking.

 		@see SDmacCaps::iChannelLinking

 		@param a1stChannel The channel which is to be linked to another channel

 		@param a2ndChannel The channel the first one is to be linked to

 		@return KErrNone if the two channels have been linked successfully,

 		KErrCompletion if a1stChannel was already linked to a2ndChannel,

 		KErrArgument if a1stChannel was already linked to a different channel,

 		KErrGeneral if a general error occurred preventing a successful

 		outcome. The default PIL implementation returns KErrNotSupported.

 	 */

 	virtual TInt LinkChannels(TDmaChannel& a1stChannel, TDmaChannel& a2ndChannel);

 	/** Called by PIL to logically unlink a physical channel from its linked-to

 		successor.

 		The function must be implemented by the PSL if the DMAC supports

 		logical channel linking.

 		@see SDmacCaps::iChannelLinking

 		@param aChannel The channel which is to be unlinked from its successor

 		@return KErrNone if the channel has been unlinked successfully,

 		KErrCompletion if the channel was not linked to another channel,

 		KErrGeneral if a general error occurred preventing a successful

 		outcome. The default PIL implementation returns KErrNotSupported.

 	 */

 	virtual TInt UnlinkChannel(TDmaChannel& aChannel);

 	/** Called by a test harness to force an error when the next fragment is

 		transferred.

 		Must be implemented by the PSL only if possible.

 		@param aChannel The channel where the error is to occur.

 		@return KErrNone if implemented. The default PIL implementation

 		returns KErrNotSupported.

 	*/

 	virtual TInt FailNext(const TDmaChannel& aChannel);

 	/** Called by a test harness to force the DMA controller to miss one or

 		more interrupts.

 		The function must be implemented by the PSL only if possible.

 		@param aChannel The channel where the error is to occur

 		@param aInterruptCount The number of interrupt to miss.

 		@return KErrNone if implemented. The default PIL implementation

 		returns KErrNotSupported.

 	*/

 	virtual TInt MissNextInterrupts(const TDmaChannel& aChannel, TInt aInterruptCount);

 	/** Function allowing platform-specific layer to extend channel API with

 		new channel-specific operations.

 		@see TDmaChannel::ChannelExtension

 		@param aChannel Channel to operate on

 		@param aCmd Command identifier. Negative values are reserved for use by

 		Nokia.

 		@param aArg PSL-specific argument

 		@return KErrNotSupported if aCmd is not supported. PSL-specific value

 		otherwise.

 	*/

 	virtual TInt Extension(TDmaChannel& aChannel, TInt aCmd, TAny* aArg);

 	/** Called by the PIL to query the number of elements that have so far been

 		transferred by the hardware descriptor associated with aHdr at the

 		source port.

 		If SDmacCaps::iAsymHwDescriptors is true then the PIL will call this

 		function only for source-side descriptors, and the PSL should fault the

 		kernel if this is not the case.

 		The function must be implemented (i.e. overridden) by the PSL if and

 		only if the DMAC supports hardware descriptors.

 		@param aHdr Descriptor header associated with the hardware descriptor

 		to be queried

 		@return The number of elements that have been transferred by the

 		hardware descriptor associated with aHdr at the source port

 	*/

 	virtual TUint32 HwDesNumSrcElementsTransferred(const SDmaDesHdr& aHdr);

 	/** Called by the PIL to query the number of elements that have so far been

 		transferred by the hardware descriptor associated with aHdr at the

 		destination port.

 		If SDmacCaps::iAsymHwDescriptors is true then the PIL will call this

 		function only for destination-side descriptors, and the PSL should

 		panic if this is not the case.

 		The function must be implemented (i.e. overridden) by the PSL if and

 		only if the DMAC supports hardware descriptors.

 		@param aHdr Descriptor header associated with the hardware descriptor

 		to be queried

 		@return The number of elements that have been transferred by the

 		hardware descriptor associated with aHdr at the destination port

 	*/

 	virtual TUint32 HwDesNumDstElementsTransferred(const SDmaDesHdr& aHdr);

 protected:

 	/** Called by the PSL in interrupt context upon a channel interrupt event.

 		@param aChannel The channel the ISR relates to

 		@param aEventMask Bitmask of one or more TDmaCallbackType values

 		@param aIsComplete Set to ETrue if no error was encountered

 	 */

 	static void HandleIsr(TDmaChannel& aChannel, TUint aEventMask, TBool aIsComplete);

 private:

 	/** Called in Create() */

 	TInt AllocDesPool(TUint aAttribs);

 	/** Called in ~TDmac() */

 	void FreeDesPool();

 private:

 	NFastMutex iLock;			 // protect descriptor reservation and allocation

 	const TInt iMaxDesCount;	 // initial number of descriptors and headers

 	TInt iAvailDesCount;		 // current available number of descriptors and headers

 	SDmaDesHdr* iHdrPool;		 // descriptor header dynamic array

 #ifndef __WINS__

 	DPlatChunkHw* iHwDesChunk;	 // chunk for hardware descriptor pool

 #endif

 	TAny* iDesPool;				 // hardware or pseudo descriptor dynamic array

 	const TInt iDesSize;		 // descriptor size in bytes

 public:

 	const TBool iCapsHwDes;		 /*< True if DMAC uses h/w descriptors */

 	SDmaDesHdr* iFreeHdr;		 /*< head of unallocated descriptors linked list */

 #ifdef _DEBUG

 	/** Tests whether aHdr points into the descriptor header array. */

 	TBool IsValidHdr(const SDmaDesHdr* aHdr);

 #endif

 	__DMA_DECLARE_INVARIANT

 	};

 //////////////////////////////////////////////////////////////////////////////

 /** Single-buffer DMA channel.

 	Can be instantiated or further derived by the PSL.

 	@publishedPartner

 	@released

 */

 class TDmaSbChannel : public TDmaChannel

 	{

 private:

 	virtual void DoQueue(const DDmaRequest& aReq);

 	virtual void DoCancelAll();

 	virtual void DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aCompletedHdr);

 private:

 	enum {EIdle = 0, ETransferring} iState;

 	};

 /** Double-buffer DMA channel.

 	Can be instantiated or further derived by the PSL.

 	@publishedPartner

 	@released

 */

 class TDmaDbChannel : public TDmaChannel

 	{

 private:

 	virtual void DoQueue(const DDmaRequest& aReq);

 	virtual void DoCancelAll();

 	virtual void DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aCompletedHdr);

 private:

 	enum {EIdle = 0, ETransferring, ETransferringLast} iState;

 	};

 /** Scatter-gather DMA channel.

 	Can be instantiated or further derived by the PSL.

 	@publishedPartner

 	@released

 */

 class TDmaSgChannel : public TDmaChannel

 	{

 private:

 	virtual void DoQueue(const DDmaRequest& aReq);

 	virtual void DoCancelAll();

 	virtual void DoUnlink(SDmaDesHdr& aHdr);

 	virtual void DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aCompletedHdr);

 private:

 	enum {EIdle = 0, ETransferring} iState;

 	};

 /** Scatter-gather DMA channel with asymmetric linked-lists.

 	Can be instantiated or further derived by the PSL.

 	@publishedPartner

 	@released

 */

 class TDmaAsymSgChannel : public TDmaChannel

 	{

 private:

 	virtual void DoQueue(const DDmaRequest& aReq);

 	virtual void DoCancelAll();

 	virtual void DoUnlink(SDmaDesHdr& aHdr);

 	virtual void DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aSrcCompletedHdr,

 					   SDmaDesHdr*& aDstCompletedHdr);

 private:

 	SDmaDesHdr* iSrcCurHdr;		   // source fragment being transferred or NULL

 	SDmaDesHdr** iSrcNullPtr; // Pointer to NULL pointer following last source fragment

 	SDmaDesHdr* iDstCurHdr;	  // destination fragment being transferred or NULL

 	SDmaDesHdr** iDstNullPtr; // Pointer to NULL pointer following last destination fragment

 	enum {EIdle = 0, ETransferring} iState;

 	};

 //////////////////////////////////////////////////////////////////////////////

 #include <drivers/dma_hai.inl>

 #endif	// #ifndef __DMA_HAI_H__