/*

File:SCSIEmulatorAdapter.cpp

Abstract: Implementation of the core a virtual SCSI HBA based off of
		IOSCSIParallelInterfaceController

Version: 1.0

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*/
#include <IOKit/IOTypes.h>
#include <IOKit/IOMessage.h>
#include <IOKit/scsi/SCSICommandOperationCodes.h>
#include <IOKit/storage/IOStorageProtocolCharacteristics.h>
#include <IOKit/scsi/spi/IOSCSIParallelInterfaceController.h>

#include "SCSIEmulator.h"
#include "SCSIEmulatorAdapter.h"
#include "SCSIEmulatorAdapterNub.h"
#include "SCSIEmulatorIOKitDriver.h"
#include "SCSIEmulatorEventSource.h"

#ifndef MAX_TARGET_ID
#define kMaxTargetID 256
#else
#define kMaxTargetID MAX_TARGET_ID
#endif

#ifndef MAX_LUNS
#define kMaxLUNs 64
#else
#define kMaxLUNs MAX_LUNS
#endif

#ifndef MAX_TASKS
#define kMaxTasks 32 // Arbitrary number.  This sample code will work with anything >= 1
#else
#define kMaxTasks MAX_TASKS
#endif

#ifndef SENSE_BUFFER_LEN
#define kSenseBufferLen 128
#else
#define kSenseBufferLen SENSE_BUFFER_LEN
#endif

#define INITIATOR_IDENTIFIER 0x87654321


// Define superclass
#define super IOSCSIParallelInterfaceController

// REQUIRED! This macro defines the class's constructors, destructors,
// and several other methods I/O Kit requires. Do NOT use super as the
// second parameter. You must use the literal name of the superclass.
OSDefineMetaClassAndStructors(com_apple_dts_SCSIEmulatorAdapter, IOSCSIParallelInterfaceController)

// Only present to provide a debug checkpoint
bool com_apple_dts_SCSIEmulatorAdapter::willTerminate(IOService *provider, IOOptionBits options)
{
    return super::willTerminate(provider, options);
}


// Only present to provide a debug checkpoint
bool com_apple_dts_SCSIEmulatorAdapter::didTerminate(IOService *provider, IOOptionBits options, bool *defer)
{
    return super::didTerminate(provider, options, defer);
}

// Only present to provide a debug checkpoint
bool
com_apple_dts_SCSIEmulatorAdapter::terminate( IOOptionBits options)
{
	bool res = super::terminate(options);
	return res;
}


IOReturn
com_apple_dts_SCSIEmulatorAdapter::message(UInt32 type, IOService *provider, void *argument)
{
	
	IOReturn ret;

#if 1 // Work-around for bug in IOSCSIParallelFamily.  Radar:4914658
	switch (type) {
		case kIOMessageServiceIsRequestingClose:
		{
			// As the provider is opened by IOSCSIParallelInterfaceController itself, it should
			// be responsible for closing it, not us.  Currently, this is not the case
			ret = super::message(type, provider, argument);

			if (getProvider()->isOpen(this))
				getProvider()->close(this);
				
			return (getProvider()->isOpen(this) == false) ? ret : kIOReturnError;

			break;
		}

		default:
		{
			break;
		}
	}
#endif

	ret = super::message(type, provider, argument);
	
	return ret;
}

SCSILogicalUnitNumber
com_apple_dts_SCSIEmulatorAdapter::ReportHBAHighestLogicalUnitNumber ( void )
{
	// Report the highest LUN number devices on this HBA are allowed to have.
	// 0 is a valid response for HBAs that only allow a single LUN per device

	SCSILogicalUnitNumber maxLUN = kMaxLUNs - 1; // Report LUNs for our sample
	return maxLUN;
}

bool
com_apple_dts_SCSIEmulatorAdapter::DoesHBASupportSCSIParallelFeature ( SCSIParallelFeature theFeature )
{
	bool ret = false; // return false for any unimplemented or unknown features

	switch (theFeature) {
		case kSCSIParallelFeature_WideDataTransfer:
			ret = true;
			break;
		case kSCSIParallelFeature_SynchronousDataTransfer:
			ret = true;
			break;
		case kSCSIParallelFeature_QuickArbitrationAndSelection:
			ret = true;
			break;
		case kSCSIParallelFeature_DoubleTransitionDataTransfers:
			ret = true;
			break;
		case kSCSIParallelFeature_InformationUnitTransfers:
			ret = true;
			break;
	}

	return ret;
}

bool
com_apple_dts_SCSIEmulatorAdapter::InitializeTargetForID ( SCSITargetIdentifier targetID )
{	
	bool retVal = false;

	com_apple_dts_SCSIEmulatorAdapterNub *nub = OSDynamicCast(com_apple_dts_SCSIEmulatorAdapterNub, getProvider());
	
	if (nub) {
		com_apple_dts_SCSIEmulator *emulator = nub->getEmulator(this, targetID);

		if (emulator) {
			if (mTargetsArray)
				mTargetsArray->setObject(targetID, emulator);

			retVal = true;
		}
	}

	return retVal;
}


SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::AbortTaskRequest ( 	
							SCSITargetIdentifier 		theT,
							SCSILogicalUnitNumber		theL,
							SCSITaggedTaskIdentifier	theQ )
{
	// Returning general failure for AbortTaskRequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}

SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::AbortTaskSetRequest (
							SCSITargetIdentifier 		theT,
							SCSILogicalUnitNumber		theL )
{
	// Returning general failure for AbortTaskSetRequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}
	
SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::ClearACARequest (
							SCSITargetIdentifier 		theT,
							SCSILogicalUnitNumber		theL )
{
	// Returning general failure for ClearACARequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}
	
SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::ClearTaskSetRequest (
							SCSITargetIdentifier 		theT,
							SCSILogicalUnitNumber		theL )
{
	// Returning general failure for ClearTaskSetRequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}
	
SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::LogicalUnitResetRequest (
							SCSITargetIdentifier 		theT,
							SCSILogicalUnitNumber		theL )
{
	// Returning general failure for LogicalUnitResetRequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}
	
SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::TargetResetRequest (
							SCSITargetIdentifier		theT )
{
	// Returning general failure for TargetResetRequest as this isn't yet supported by our HBA

	return kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
}

SCSIInitiatorIdentifier
com_apple_dts_SCSIEmulatorAdapter::ReportInitiatorIdentifier ( void )
{
	// What device ID does our HBA occupy on the bus?

	SCSIInitiatorIdentifier ourIdentity = INITIATOR_IDENTIFIER;
	return ourIdentity;
}

SCSIDeviceIdentifier
com_apple_dts_SCSIEmulatorAdapter::ReportHighestSupportedDeviceID ( void )
{
	// This HBA can handle how many attached devices?  The actual number can be lower

	SCSIDeviceIdentifier highestValidDevice = kMaxTargetID;
	return highestValidDevice;
}

UInt32
com_apple_dts_SCSIEmulatorAdapter::ReportMaximumTaskCount ( void )
{
	// How many concurrent tasks does our HBA support?
	// Given that this is the parallel tasking SCSI family, you'd
	// expect this to be greater than 1, but single task HBAs are
	// supported as well

	UInt32 maxTasks = kMaxTasks;
	return maxTasks;
}

UInt32
com_apple_dts_SCSIEmulatorAdapter::ReportHBASpecificTaskDataSize ( void )
{
	// How much space do we need allocated internally for each task?

	UInt32 taskDataSize = sizeof(SCSIEmulatorRequestBlock);
	return taskDataSize;
}

UInt32
com_apple_dts_SCSIEmulatorAdapter::ReportHBASpecificDeviceDataSize ( void )
{
	// How much space do we need allocated internally for each attached device?

	UInt32 hbaDataSize = sizeof(com_apple_dts_SCSIEmulator *);
	return hbaDataSize;
}

bool
com_apple_dts_SCSIEmulatorAdapter::DoesHBAPerformDeviceManagement ( void )
{
	// Report that we *DO NOT* manage our own devices
	// We will have the system query each possible target during startup
	// and do not expect or handle changes to this list while running

	// If you know that the bus is static and won't change, you can report false here and let the
	// OS handle discovering any attached devices.  If this is a SCSI bus where devices can be
	// dynamically added/removed, then you will need to return true and have a mechanism for
	// detecting, adding and removing devices as needed.

#if 0
	// If you were to do device management yourself, you would have to do something like:
	SCSIDeviceIdentifier index = 0
	CreateTargetForID(index++);
	
	// Use DestroyTargetForID() to remove targets as they disappear
#endif

	// This HBA does not support a mechanism for device attach/detach 
	// notification, go ahead and create target devices.
	return false;
}

bool
com_apple_dts_SCSIEmulatorAdapter::InitializeController ( void )
{
	com_apple_dts_SCSIEmulatorAdapterNub *nub = NULL;
	IOReturn ret = kIOReturnSuccess;

	nub	= OSDynamicCast(com_apple_dts_SCSIEmulatorAdapterNub, getProvider());
	if (!nub) {
		IOLog("InitializeController: failed to cast provider\n");
		goto failed;
	}

	mTargetsArray = OSArray::withCapacity(kMaxTargetID);
	
	mResponderEventSource = OSTypeAlloc(com_apple_dts_SCSIEmulatorEventSource);
	if (!mResponderEventSource) {
		IOLog("InitializeController: failed to alloc mResponderEventSource\n");
		goto failed;
	}

	if (!mResponderEventSource->init(this,  &com_apple_dts_SCSIEmulatorAdapter::TaskComplete)) {
		IOLog("InitializeController: failed to init mResponderEventSource\n");
		mResponderEventSource->release();
		goto failed;
	}

	ret = GetWorkLoop()->addEventSource(mResponderEventSource);
	if (ret != kIOReturnSuccess) {
		IOLog("InitializeController: failed to add event source.  ret = 0x%X\n", ret);
		mResponderEventSource->release();
		goto failed;
	}

	goto success;
	
failed:
	return false;
	
success:
	// The controller is now initialized and ready for operation
	return true;
}

void
com_apple_dts_SCSIEmulatorAdapter::TerminateController ( void )
{
	if (GetWorkLoop()->removeEventSource(mResponderEventSource) != kIOReturnSuccess) {
		IOLog("TerminateController: failed to de-register eventsource?\n");
	}

	if (mResponderEventSource)
		mResponderEventSource->release();

	if (mTargetsArray)
		mTargetsArray->release();
}

bool
com_apple_dts_SCSIEmulatorAdapter::StartController ( void )
{
	// Start providing HBA services.  Re-init anything needed and go

	return true;
}

void
com_apple_dts_SCSIEmulatorAdapter::StopController ( void )
{
	// We've been requested to stop providing HBA services.  Clean up and shut down
}

void
com_apple_dts_SCSIEmulatorAdapter::HandleInterruptRequest ( void )
{
	// OK, odds are, your driver will want to do something here to get info from the HBA.
	// Usually, this will be pulling task completion info, etc. and then calling TaskCompleted().
	//
	// this->TaskCompleted(task, transportSucceeded, scsiStatus, transferredDataLength, senseData, senseDataLength);
	//

	// Since this example operates without using a real primary interrupt, this will never get called
	IOLog("HandleInterruptRequest: captured interrupt?");
}

SCSIServiceResponse
com_apple_dts_SCSIEmulatorAdapter::ProcessParallelTask ( SCSIParallelTaskIdentifier parallelRequest )
{
	// Not all of these may be required.  Unused ones are commented out to avoid compiler warnings
	SCSITargetIdentifier		targetID				= GetTargetIdentifier(parallelRequest);
//	SCSITaskIdentifier			task					= GetSCSITaskIdentifier(parallelRequest);
//	SCSITaggedTaskIdentifier	taggedTask				= GetTaggedTaskIdentifier(parallelRequest);
	SCSILogicalUnitNumber		lun						= GetLogicalUnitNumber(parallelRequest);
//	SCSITaskAttribute			taskAttribute			= GetTaskAttribute(parallelRequest);
	
	UInt8						transferDir				= GetDataTransferDirection(parallelRequest);
	UInt64						transferSize			= GetRequestedDataTransferCount(parallelRequest);
	IOMemoryDescriptor *		transferMemDesc			= GetDataBuffer(parallelRequest);
//	UInt64						transferMemDescOffset   = GetDataBufferOffset(parallelRequest);

	// Get the CDB
	UInt8						cdbLength				= GetCommandDescriptorBlockSize(parallelRequest);
	SCSICommandDescriptorBlock  cdbData;
	
	SCSITaskStatus 				scsiStatus 				= kSCSITaskStatus_GOOD;
	UInt64 						dataLen 				= 0;

	UInt8						senseBuffer[kSenseBufferLen];
	UInt64						senseBufferLen 			= sizeof(senseBuffer);

	com_apple_dts_SCSIEmulator *emulator = (com_apple_dts_SCSIEmulator *)mTargetsArray->getObject(targetID);

	// Fail if we don't have a SCSI emulator backing this target
	if (!emulator) {
		IOLog("ProcessParallelTask: ABORT - !emulator for targetID = %ud\n", targetID);
		goto failure_exit;
	}

	// Fail if we're supposed to transfer data and don't have a data buffer
	if (!transferMemDesc && (transferDir != kSCSIDataTransfer_NoDataTransfer)) {
		IOLog("ProcessParallelTask: ABORT - !transferMemDesc && (transferDir != kSCSIDataTransfer_NoDataTransfer) - %p and %d\n", transferMemDesc, transferDir);
		goto failure_exit;
	}

	// Fail if we don't have a large enough CDB buffer set aside
	if (cdbLength > sizeof(cdbData)) {
		IOLog("ProcessParallelTask: ABORT - cdbLength > sizeof(cdbData) - %d vs. %d\n", cdbLength, sizeof(cdbData));
		goto failure_exit;
	}

	if (!GetCommandDescriptorBlock(parallelRequest, &cdbData)) {
		IOLog("ProcessParallelTask: ABORT - !GetCommandDescriptorBlock(parallelRequest, &cdbData)\n");
		goto failure_exit;
	}

	if (transferMemDesc && (transferDir != kSCSIDataTransfer_NoDataTransfer)) {
#if 0
		// This block isn't necessary as memory descriptors passed in are always autoprepared for us.
		// Remember: Any memory descriptors allocated and used internally should be prepared before sending
		// or receiving data to/from real hardware
		IOReturn res = transferMemDesc->prepare();
		if (res != kIOReturnSuccess) {
			goto failure_exit;
		}
#endif

		// We are guaranteed that the memory descriptor will always be sized large enough by
		// by SAM/STUC to hold the transfer size requested
		dataLen = transferSize;
	}

	// This is where the "real" work should get done by your hardware.  The individual parameters
	// are being sent instead of just the task reference as the task is opaque by design and
	// the getter/setter methods are protected and available within this class, but not within
	// the emulator itself.
	emulator->sendCommand(cdbData, cdbLength, transferMemDesc, &dataLen, lun, &scsiStatus, senseBuffer, &senseBufferLen);

	// Real hardware should be doing the task processing internally and providing responses
	// via an interrupt mechanism.  IOSCSIParallelInterfaceController expects this and you
	// should always do your task completions from the workloop thread.
	CompleteTaskOnWorkloopThread(parallelRequest, true, scsiStatus, dataLen, senseBuffer, senseBufferLen);
	return kSCSIServiceResponse_Request_In_Process;

failure_exit:
	CompleteTaskOnWorkloopThread(parallelRequest, false, scsiStatus, dataLen, senseBuffer, senseBufferLen);
	return kSCSIServiceResponse_Request_In_Process;
}

void
com_apple_dts_SCSIEmulatorAdapter::CompleteTaskOnWorkloopThread (
	SCSIParallelTaskIdentifier		parallelRequest,
	bool							transportSuccessful,
	SCSITaskStatus					scsiStatus,
	UInt64							actuallyTransferred,
	UInt8*							senseBuffer,
	int								senseLength)
{
//	SCSITargetIdentifier		target					= GetTargetIdentifier(parallelRequest);
	UInt8						transferDir				= GetDataTransferDirection(parallelRequest);
	UInt64						transferSizeMax			= GetRequestedDataTransferCount(parallelRequest);
//	IOMemoryDescriptor *		transferMemDesc			= GetDataBuffer(parallelRequest);
	SCSIEmulatorRequestBlock *	srb						= ( SCSIEmulatorRequestBlock * ) GetHBADataPointer ( parallelRequest );
	
	if (transportSuccessful && (scsiStatus != kSCSITaskStatus_TASK_SET_FULL)) {
		// set the realized transfer counts
		switch (transferDir) {
			case kSCSIDataTransfer_FromTargetToInitiator:
			{
				if (actuallyTransferred > transferSizeMax) {
					actuallyTransferred = transferSizeMax;
				}
				if (!SetRealizedDataTransferCount(parallelRequest, actuallyTransferred)) {
					IOLog("CompleteTaskOnWorkloopThread: SetRealizedDataTransferCount (%d bytes) returned FAIL\n", actuallyTransferred);
				}
				break;
			}
			case kSCSIDataTransfer_FromInitiatorToTarget:
			{
				if (actuallyTransferred > transferSizeMax) {
					actuallyTransferred = transferSizeMax;
				}
				if (!SetRealizedDataTransferCount(parallelRequest, actuallyTransferred)) {
					IOLog("CompleteTaskOnWorkloopThread: SetRealizedDataTransferCount (%d bytes) returned FAIL\n", actuallyTransferred);
				}
				break;
			}
			case kSCSIDataTransfer_NoDataTransfer:
			default:
			{
				break;
			}
		}
	}

	// Now, add the completion to the queue to be checked by the workloop thread.  The completion needs
	// to be done on the workloop to allow the stack to unwind itself or you risk running into a panic.
	// The addItemToQueue method in the event source signals the workloop to check the queue after the task
	// is added.
	if (!transportSuccessful) {
		IOLog("CompleteTaskOnWorkloopThread: Failed transport - task = %p, transferDir = %d, transferSize = %lld, scsiStatus = 0x%X\n", parallelRequest, transferDir, transferSizeMax, scsiStatus);
		
		queue_init(&srb->fQueueChain);
		srb->fTask = parallelRequest;
		srb->fTaskStatus = scsiStatus;
		srb->fServiceResponse = kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
		
		mResponderEventSource->addItemToQueue(srb);
		
	} else {
		// handle sense data in common fashion and complete the task
		if (senseLength > 0) {
			if (!SetAutoSenseData(parallelRequest, (SCSI_Sense_Data*) senseBuffer, senseLength)) {
				IOLog("CompleteTaskOnWorkloopThread: Could not set sense data in parallel task\n");
			}
		}
		
		queue_init(&srb->fQueueChain);
		srb->fTask = parallelRequest;
		srb->fTaskStatus = scsiStatus;
		srb->fServiceResponse = kSCSIServiceResponse_TASK_COMPLETE;
		
		mResponderEventSource->addItemToQueue(srb);
	}
	
}

void
com_apple_dts_SCSIEmulatorAdapter::TaskComplete (com_apple_dts_SCSIEmulatorAdapter *owner, SCSIEmulatorRequestBlock response)
{
	owner->CompleteParallelTask(response.fTask, response.fTaskStatus, response.fServiceResponse);
}