/*
	FreeRTOS V5.4.2 - Copyright (C) 2009 Real Time Engineers Ltd.

	This file is part of the FreeRTOS distribution.

	FreeRTOS is free software; you can redistribute it and/or modify it	under 
	the terms of the GNU General Public License (version 2) as published by the 
	Free Software Foundation and modified by the FreeRTOS exception.
	**NOTE** The exception to the GPL is included to allow you to distribute a
	combined work that includes FreeRTOS without being obliged to provide the 
	source code for proprietary components outside of the FreeRTOS kernel.  
	Alternative commercial license and support terms are also available upon 
	request.  See the licensing section of http://www.FreeRTOS.org for full 
	license details.

	FreeRTOS is distributed in the hope that it will be useful,	but WITHOUT
	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
	more details.

	You should have received a copy of the GNU General Public License along
	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
	Temple Place, Suite 330, Boston, MA  02111-1307  USA.


	***************************************************************************
	*                                                                         *
	* Looking for a quick start?  Then check out the FreeRTOS eBook!          *
	* See http://www.FreeRTOS.org/Documentation for details                   *
	*                                                                         *
	***************************************************************************

	1 tab == 4 spaces!

	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	http://www.FreeRTOS.org - Documentation, latest information, license and
	contact details.

	http://www.SafeRTOS.com - A version that is certified for use in safety
	critical systems.

	http://www.OpenRTOS.com - Commercial support, development, porting,
	licensing and training services.
*/

/*
	USB Communications Device Class driver.
	Implements task vUSBCDCTask and provides an Abstract Control Model serial 
	interface.  Control is through endpoint 0, device-to-host notification is 
	provided by interrupt-in endpoint 3, and raw data is transferred through 
	bulk endpoints 1 and 2.

	- developed from original FreeRTOS HID example by Scott Miller
	- modified to support 3.2 GCC by najay
*/

/* Standard includes. */
#include <string.h>
#include <stdio.h>

/* Demo board includes. */
#include "Board.h"

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

/* Demo app includes. */
#include "USB-CDC.h"
#include "descriptors.h"

#define usbNO_BLOCK ( ( portTickType ) 0 )

/* Reset all endpoints */
static void prvResetEndPoints( void );

/* Clear pull up resistor to detach device from host */
static void vDetachUSBInterface( void );

/* Set up interface and initialize variables */
static void vInitUSBInterface( void );

/* Handle control endpoint events. */
static void prvProcessEndPoint0Interrupt( xISRStatus *pxMessage );

/* Handle standard device requests. */
static void prvHandleStandardDeviceRequest( xUSB_REQUEST *pxRequest );

/* Handle standard interface requests. */
static void prvHandleStandardInterfaceRequest( xUSB_REQUEST *pxRequest );

/* Handle endpoint requests. */
static void prvHandleStandardEndPointRequest( xUSB_REQUEST *pxRequest );

/* Handle class interface requests. */
static void prvHandleClassInterfaceRequest( xUSB_REQUEST *pxRequest );

/* Prepare control data transfer.  prvSendNextSegment starts transfer. */
static void prvSendControlData( unsigned portCHAR *pucData, unsigned portSHORT usRequestedLength, unsigned portLONG ulLengthLeftToSend, portLONG lSendingDescriptor );

/* Send next segment of data for the control transfer */
static void prvSendNextSegment( void );

/* Send stall - used to respond to unsupported requests */
static void prvSendStall( void );

/* Send a zero-length (null) packet */
static void prvSendZLP( void );

/* Handle requests for standard interface descriptors */
static void prvGetStandardInterfaceDescriptor( xUSB_REQUEST *pxRequest );

/*------------------------------------------------------------*/

/* File scope static variables */
static unsigned portCHAR ucUSBConfig = ( unsigned portCHAR ) 0;
static unsigned portLONG ulReceivedAddress = ( unsigned portLONG ) 0;
static eDRIVER_STATE eDriverState = eNOTHING;

/* Incoming and outgoing control data structures */
static xCONTROL_MESSAGE pxControlTx;
static xCONTROL_MESSAGE pxControlRx;

/* Queue holding pointers to pending messages */
xQueueHandle xUSBInterruptQueue; 

/* Queues used to hold received characters, and characters waiting to be
transmitted.  Rx queue must be larger than FIFO size. */
static xQueueHandle xRxCDC; 
static xQueueHandle xTxCDC; 

/* Line coding - 115,200 baud, N-8-1 */
static const unsigned portCHAR pxLineCoding[] = { 0x00, 0xC2, 0x01, 0x00, 0x00, 0x00, 0x08 };

/* Status variables. */
static unsigned portCHAR ucControlState;
static unsigned int uiCurrentBank;


/*------------------------------------------------------------*/


void vUSBCDCTask( void *pvParameters )
{
xISRStatus *pxMessage;
unsigned portLONG ulStatus;
unsigned portLONG ulRxBytes;
unsigned portCHAR ucByte;
portBASE_TYPE xByte;

	( void ) pvParameters;

	/* Disconnect USB device from hub.  For debugging - causes host to register reset */
	portENTER_CRITICAL();
		 vDetachUSBInterface();
	portEXIT_CRITICAL();
	
	vTaskDelay( portTICK_RATE_MS * 60 );

	/* Init USB interface */
	portENTER_CRITICAL();
		vInitUSBInterface();
	portEXIT_CRITICAL();
	
	/* Main task loop.  Process incoming endpoint 0 interrupts, handle data transfers. */
	 
	for( ;; )
	{
		/* Look for data coming from the ISR. */
		if( xQueueReceive( xUSBInterruptQueue, &pxMessage, usbSHORTEST_DELAY ) )
		{
			if( pxMessage->ulISR & AT91C_UDP_EPINT0 )
			{
				/* All endpoint 0 interrupts are handled here. */
				prvProcessEndPoint0Interrupt( pxMessage );
			}

			if( pxMessage->ulISR & AT91C_UDP_ENDBUSRES )
			{
				/* End of bus reset - reset the endpoints and de-configure. */
				prvResetEndPoints();		
			}
		}
		
		/* See if we're ready to send and receive data. */
		if( eDriverState == eREADY_TO_SEND && ucControlState ) 
		{
			if( ( !(AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ] & AT91C_UDP_TXPKTRDY) ) && uxQueueMessagesWaiting( xTxCDC ) )
			{
				for( xByte = 0; xByte < 64; xByte++ )
				{				   
					if( !xQueueReceive( xTxCDC, &ucByte, 0 ) ) 
					{
						/* No data buffered to transmit. */
						break;
					}

					/* Got a byte to transmit. */
					AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_2 ] = ucByte;
				} 
				AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ] |= AT91C_UDP_TXPKTRDY;
			}

			/* Check for incoming data (host-to-device) on endpoint 1. */
			while( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] & (AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1) )
			{
				ulRxBytes = (AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] >> 16) & usbRX_COUNT_MASK;

				/* Only process FIFO if there's room to store it in the queue */
				if( ulRxBytes < ( USB_CDC_QUEUE_SIZE - uxQueueMessagesWaiting( xRxCDC ) ) )
				{
					while( ulRxBytes-- )
					{
						ucByte = AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_1 ];
						xQueueSend( xRxCDC, &ucByte, 0 );
					}

					/* Release the FIFO */
					portENTER_CRITICAL();
					{
						ulStatus = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ];
						usbCSR_CLEAR_BIT( &ulStatus, uiCurrentBank );
						AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] = ulStatus;
					}
					portEXIT_CRITICAL();

					/* Re-enable endpoint 1's interrupts */
					AT91C_BASE_UDP->UDP_IER = AT91C_UDP_EPINT1;
				
					/* Update the current bank in use */
					if( uiCurrentBank == AT91C_UDP_RX_DATA_BK0 ) 
					{
						uiCurrentBank = AT91C_UDP_RX_DATA_BK1;
					}
					else 
					{
						uiCurrentBank = AT91C_UDP_RX_DATA_BK0;
					}

				}
				else 
				{
					break;
				}
			}
		}
	}
}
/*------------------------------------------------------------*/

void vUSBSendByte( portCHAR cByte )
{
	/* Queue the byte to be sent.  The USB task will send it. */
	xQueueSend( xTxCDC, &cByte, usbNO_BLOCK );
}
/*------------------------------------------------------------*/

static void prvSendZLP( void )
{
unsigned portLONG ulStatus;

	/* Wait until the FIFO is free - even though we are not going to use it.
	THERE IS NO TIMEOUT HERE! */
	while( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_TXPKTRDY )
	{
		vTaskDelay( usbSHORTEST_DELAY );
	}

	portENTER_CRITICAL();
	{
		/* Cancel any further pending data */
		pxControlTx.ulTotalDataLength = pxControlTx.ulNextCharIndex;

		/* Set the TXPKTRDY bit to cause a transmission with no data. */
		ulStatus = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];
		usbCSR_SET_BIT( &ulStatus, AT91C_UDP_TXPKTRDY );
		AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulStatus;
	}
	portEXIT_CRITICAL();
}
/*------------------------------------------------------------*/

static void prvSendStall( void )
{
	unsigned portLONG ulStatus;

	portENTER_CRITICAL();
	{
		/* Force a stall by simply setting the FORCESTALL bit in the CSR. */
		ulStatus = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];
		usbCSR_SET_BIT( &ulStatus, AT91C_UDP_FORCESTALL );
		AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulStatus;
	}
	portEXIT_CRITICAL();
}
/*------------------------------------------------------------*/

static void prvResetEndPoints( void )
{
unsigned portLONG ulTemp;

	eDriverState = eJUST_RESET;
	ucControlState = 0;

	/* Reset all the end points. */
	AT91C_BASE_UDP->UDP_RSTEP  = usbEND_POINT_RESET_MASK;
	AT91C_BASE_UDP->UDP_RSTEP  = ( unsigned portLONG ) 0x00;

	/* Enable data to be sent and received. */
	AT91C_BASE_UDP->UDP_FADDR = AT91C_UDP_FEN;

	/* Repair the configuration end point. */
	portENTER_CRITICAL();
	{
		ulTemp = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];
		usbCSR_SET_BIT( &ulTemp, ( ( unsigned portLONG ) ( AT91C_UDP_EPEDS | AT91C_UDP_EPTYPE_CTRL ) ) );
		AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulTemp;
		AT91C_BASE_UDP->UDP_IER = AT91C_UDP_EPINT0;
	}
	portEXIT_CRITICAL();
	uiCurrentBank = AT91C_UDP_RX_DATA_BK0;
}
/*------------------------------------------------------------*/

static void prvProcessEndPoint0Interrupt( xISRStatus *pxMessage )
{
static xUSB_REQUEST xRequest;
unsigned portLONG ulRxBytes;

	/* Get number of bytes received, if any */
	ulRxBytes = pxMessage->ulCSR0 >> 16;
	ulRxBytes &= usbRX_COUNT_MASK;

	if( pxMessage->ulCSR0 & AT91C_UDP_TXCOMP )
	{
		/* We received a TX complete interrupt.  What we do depends on
		what we sent to get this interrupt. */

		if( eDriverState == eJUST_GOT_CONFIG )
		{
			/* We sent an acknowledgement of a SET_CONFIG request.  We
			are now at the end of the enumeration.
			
			TODO: Config 0 sets unconfigured state, should enter Address state.
			Request for unsupported config should stall. */
			AT91C_BASE_UDP->UDP_GLBSTATE = AT91C_UDP_CONFG;
			
			/* Set up endpoints */
			portENTER_CRITICAL();
			{
				unsigned portLONG ulTemp;

				/* Set endpoint 1 to bulk-out */
				ulTemp = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ];					
				usbCSR_SET_BIT( &ulTemp, AT91C_UDP_EPEDS | AT91C_UDP_EPTYPE_BULK_OUT );
				AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] = ulTemp;		
				AT91C_BASE_UDP->UDP_IER = AT91C_UDP_EPINT1;
				/* Set endpoint 2 to bulk-in */
				ulTemp = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ];					
				usbCSR_SET_BIT( &ulTemp, AT91C_UDP_EPEDS | AT91C_UDP_EPTYPE_BULK_IN );
				AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ] = ulTemp;		
				AT91C_BASE_UDP->UDP_IER = AT91C_UDP_EPINT2;
					/* Set endpoint 3 to interrupt-in, enable it, and enable interrupts */
				ulTemp = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_3 ];					
				usbCSR_SET_BIT( &ulTemp, AT91C_UDP_EPEDS | AT91C_UDP_EPTYPE_INT_IN );
				AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_3 ] = ulTemp;		
				/*AT91F_UDP_EnableIt( AT91C_BASE_UDP, AT91C_UDP_EPINT3 );				 */
			}
			portEXIT_CRITICAL();

			eDriverState = eREADY_TO_SEND;
		}		
		else if( eDriverState == eJUST_GOT_ADDRESS )
		{
			/* We sent an acknowledgement of a SET_ADDRESS request.  Move
			to the addressed state. */
			if( ulReceivedAddress != ( unsigned portLONG ) 0 )
			{			
				AT91C_BASE_UDP->UDP_GLBSTATE = AT91C_UDP_FADDEN;
			}
			else
			{
				AT91C_BASE_UDP->UDP_GLBSTATE = 0;
			}			

			AT91C_BASE_UDP->UDP_FADDR = ( AT91C_UDP_FEN | ulReceivedAddress );		
			eDriverState = eNOTHING;
		}
		else
		{		
			/* The TXCOMP was not for any special type of transmission.  See
			if there is any more data to send. */
			prvSendNextSegment();
		}
	}

	if( pxMessage->ulCSR0 & AT91C_UDP_RX_DATA_BK0 )
	{
		/* Received a control data packet.  May be a 0-length ACK or a data stage. */
		unsigned portCHAR ucBytesToGet;
	 
		/* Got data.  Cancel any outgoing data. */
		pxControlTx.ulNextCharIndex = pxControlTx.ulTotalDataLength;
		
		 /* Determine how many bytes we need to receive. */
		ucBytesToGet = pxControlRx.ulTotalDataLength - pxControlRx.ulNextCharIndex;
		if( ucBytesToGet > ulRxBytes ) 
		{	
			ucBytesToGet = ulRxBytes;
		}

		/* If we're not expecting any data, it's an ack - just quit now. */
		if( !ucBytesToGet )
		{
			 return;
		}

		/* Get the required data and update the index. */
		memcpy( pxControlRx.ucBuffer, pxMessage->ucFifoData, ucBytesToGet );
		pxControlRx.ulNextCharIndex += ucBytesToGet;	
	}

	if( pxMessage->ulCSR0 & AT91C_UDP_RXSETUP )
	{
		/* Received a SETUP packet.  May be followed by data packets. */

		if( ulRxBytes >= usbEXPECTED_NUMBER_OF_BYTES )
		{		 		
			/* Create an xUSB_REQUEST variable from the raw bytes array. */

			xRequest.ucReqType = pxMessage->ucFifoData[ usbREQUEST_TYPE_INDEX ];
			xRequest.ucRequest = pxMessage->ucFifoData[ usbREQUEST_INDEX ];

			xRequest.usValue = pxMessage->ucFifoData[ usbVALUE_HIGH_BYTE ];
			xRequest.usValue <<= 8;
			xRequest.usValue |= pxMessage->ucFifoData[ usbVALUE_LOW_BYTE ];
						
			xRequest.usIndex = pxMessage->ucFifoData[ usbINDEX_HIGH_BYTE ];
			xRequest.usIndex <<= 8;
			xRequest.usIndex |= pxMessage->ucFifoData[ usbINDEX_LOW_BYTE ];
			
			xRequest.usLength = pxMessage->ucFifoData[ usbLENGTH_HIGH_BYTE ];
			xRequest.usLength <<= 8;
			xRequest.usLength |= pxMessage->ucFifoData[ usbLENGTH_LOW_BYTE ];

			pxControlRx.ulNextCharIndex = 0;
			if( ! (xRequest.ucReqType & 0x80) ) /* Host-to-Device transfer, may need to get data first */
			{
				if( xRequest.usLength > usbMAX_CONTROL_MESSAGE_SIZE )
				{	
					/* Too big!  No space for control data, stall and abort. */
					prvSendStall();
					return;
				}

				pxControlRx.ulTotalDataLength = xRequest.usLength;
			}
			else
			{
				/* We're sending the data, don't wait for any. */
				pxControlRx.ulTotalDataLength = 0; 
			}
		}
	}

	/* See if we've got a pending request and all its associated data ready */
	if( ( pxMessage->ulCSR0 & ( AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RXSETUP ) ) 
		&& ( pxControlRx.ulNextCharIndex >= pxControlRx.ulTotalDataLength ) )
	{
		unsigned portCHAR ucRequest;

		/* Manipulate the ucRequestType and the ucRequest parameters to 
		generate a zero based request selection.  This is just done to 
		break up the requests into subsections for clarity.  The 
		alternative would be to have more huge switch statement that would
		be difficult to optimise. */
		ucRequest = ( ( xRequest.ucReqType & 0x60 ) >> 3 );
		ucRequest |= ( xRequest.ucReqType & 0x03 );
			
		switch( ucRequest )
		{
			case usbSTANDARD_DEVICE_REQUEST:	
				/* Standard Device request */
				prvHandleStandardDeviceRequest( &xRequest );
				break;

			case usbSTANDARD_INTERFACE_REQUEST:	
				/* Standard Interface request */
				prvHandleStandardInterfaceRequest( &xRequest );
				break;

			case usbSTANDARD_END_POINT_REQUEST:	
				/* Standard Endpoint request */
				prvHandleStandardEndPointRequest( &xRequest );
				break;

			case usbCLASS_INTERFACE_REQUEST:	
				/* Class Interface request */
				prvHandleClassInterfaceRequest( &xRequest );
				break;

			default:	/* This is not something we want to respond to. */
				prvSendStall();	
		}
	}
}
/*------------------------------------------------------------*/

static void prvGetStandardDeviceDescriptor( xUSB_REQUEST *pxRequest )
{
	/* The type is in the high byte.  Return whatever has been requested. */
	switch( ( pxRequest->usValue & 0xff00 ) >> 8 )
	{
		case usbDESCRIPTOR_TYPE_DEVICE:
			prvSendControlData( ( unsigned portCHAR * ) &pxDeviceDescriptor, pxRequest->usLength, sizeof( pxDeviceDescriptor ), pdTRUE );
			break;

		case usbDESCRIPTOR_TYPE_CONFIGURATION:
			prvSendControlData( ( unsigned portCHAR * ) &( pxConfigDescriptor ), pxRequest->usLength, sizeof( pxConfigDescriptor ), pdTRUE );
			break;

		case usbDESCRIPTOR_TYPE_STRING:

			/* The index to the string descriptor is the lower byte. */
			switch( pxRequest->usValue & 0xff )
			{			
				case usbLANGUAGE_STRING:
					prvSendControlData( ( unsigned portCHAR * ) &pxLanguageStringDescriptor, pxRequest->usLength, sizeof(pxLanguageStringDescriptor), pdTRUE );
					break;

				case usbMANUFACTURER_STRING:
					prvSendControlData( ( unsigned portCHAR * ) &pxManufacturerStringDescriptor, pxRequest->usLength, sizeof( pxManufacturerStringDescriptor ), pdTRUE );
					break;

				case usbPRODUCT_STRING:
					prvSendControlData( ( unsigned portCHAR * ) &pxProductStringDescriptor, pxRequest->usLength, sizeof( pxProductStringDescriptor ), pdTRUE );
					break;

				case usbCONFIGURATION_STRING:
					prvSendControlData( ( unsigned portCHAR * ) &pxConfigurationStringDescriptor, pxRequest->usLength, sizeof( pxConfigurationStringDescriptor ), pdTRUE );
					break;

				case usbINTERFACE_STRING:
					prvSendControlData( ( unsigned portCHAR * ) &pxInterfaceStringDescriptor, pxRequest->usLength, sizeof( pxInterfaceStringDescriptor ), pdTRUE );
					break;

				default:
					prvSendStall();
					break;
			}
			break;

		default:
			prvSendStall();
			break;
	}
}
/*------------------------------------------------------------*/

static void prvHandleStandardDeviceRequest( xUSB_REQUEST *pxRequest )
{
unsigned portSHORT usStatus = 0;

	switch( pxRequest->ucRequest )
	{
		case usbGET_STATUS_REQUEST:
			/* Just send two byte dummy status. */
			prvSendControlData( ( unsigned portCHAR * ) &usStatus, sizeof( usStatus ), sizeof( usStatus ), pdFALSE );
			break;

		case usbGET_DESCRIPTOR_REQUEST:
			/* Send device descriptor */
			prvGetStandardDeviceDescriptor( pxRequest );
			break;

		case usbGET_CONFIGURATION_REQUEST:
			/* Send selected device configuration */
			prvSendControlData( ( unsigned portCHAR * ) &ucUSBConfig, sizeof( ucUSBConfig ), sizeof( ucUSBConfig ), pdFALSE );
			break;

		case usbSET_FEATURE_REQUEST:
			prvSendZLP();
			break;

		case usbSET_ADDRESS_REQUEST:			
			/* Get assigned address and send ack, but don't implement new address until we get a TXCOMP */
			prvSendZLP();			
			eDriverState = eJUST_GOT_ADDRESS;			
			ulReceivedAddress = ( unsigned portLONG ) pxRequest->usValue;
			break;

		case usbSET_CONFIGURATION_REQUEST:
			/* Ack SET_CONFIGURATION request, but don't implement until TXCOMP */
			ucUSBConfig = ( unsigned portCHAR ) ( pxRequest->usValue & 0xff );
			eDriverState = eJUST_GOT_CONFIG;
			prvSendZLP();
			break;

		default:
			/* Any unsupported request results in a STALL response. */
			prvSendStall();
			break;
	}
}
/*------------------------------------------------------------*/

static void prvHandleClassInterfaceRequest( xUSB_REQUEST *pxRequest )
{
	switch( pxRequest->ucRequest )
	{
		case usbSEND_ENCAPSULATED_COMMAND:
			prvSendStall();
			break;

		case usbGET_ENCAPSULATED_RESPONSE:
			prvSendStall();
			break;

		case usbSET_LINE_CODING:
			/* Set line coding - baud rate, data bits, parity, stop bits */
			prvSendZLP();
			memcpy( ( void * ) pxLineCoding, pxControlRx.ucBuffer, sizeof( pxLineCoding ) );
			break;

		case usbGET_LINE_CODING:
			/* Get line coding */
			prvSendControlData( (unsigned portCHAR *) &pxLineCoding, pxRequest->usLength, sizeof( pxLineCoding ), pdFALSE );
			break;

		case usbSET_CONTROL_LINE_STATE:
			/* D0: 1=DTR, 0=No DTR,  D1: 1=Activate Carrier, 0=Deactivate carrier (RTS, half-duplex) */
			prvSendZLP();
			ucControlState = pxRequest->usValue;
			break;

		default:
			prvSendStall();
			break;
	}
}
/*------------------------------------------------------------*/

static void prvGetStandardInterfaceDescriptor( xUSB_REQUEST *pxRequest )
{
	switch( ( pxRequest->usValue & ( unsigned portSHORT ) 0xff00 ) >> 8 )
	{
		default:
			prvSendStall();
			break;
	}
}
/*-----------------------------------------------------------*/

static void prvHandleStandardInterfaceRequest( xUSB_REQUEST *pxRequest )
{
unsigned portSHORT usStatus = 0;

	switch( pxRequest->ucRequest )
	{
		case usbGET_STATUS_REQUEST:
			/* Send dummy 2 bytes. */
			prvSendControlData( ( unsigned portCHAR * ) &usStatus, sizeof( usStatus ), sizeof( usStatus ), pdFALSE );
			break;

		case usbGET_DESCRIPTOR_REQUEST:
			prvGetStandardInterfaceDescriptor( pxRequest ); 
			break;

		/* This minimal implementation does not respond to these. */
		case usbGET_INTERFACE_REQUEST:
		case usbSET_FEATURE_REQUEST:
		case usbSET_INTERFACE_REQUEST:	

		default:
			prvSendStall();
			break;
	}
}
/*-----------------------------------------------------------*/

static void prvHandleStandardEndPointRequest( xUSB_REQUEST *pxRequest )
{
	switch( pxRequest->ucRequest )
	{
		/* This minimal implementation does not expect to respond to these. */
		case usbGET_STATUS_REQUEST:
		case usbCLEAR_FEATURE_REQUEST: 
		case usbSET_FEATURE_REQUEST:

		default:			
			prvSendStall();
			break;
	}
}
/*-----------------------------------------------------------*/

static void vDetachUSBInterface( void)
{
	/* Setup the PIO for the USB pull up resistor. */
	AT91C_BASE_PIOA->PIO_PER = AT91C_PIO_PA16;
	AT91C_BASE_PIOA->PIO_OER = AT91C_PIO_PA16;


	/* Disable pull up */
	AT91C_BASE_PIOA->PIO_SODR = AT91C_PIO_PA16;
} 
/*-----------------------------------------------------------*/

static void vInitUSBInterface( void )
{
extern void ( vUSB_ISR_Wrapper )( void );

	/* Create the queue used to communicate between the USB ISR and task. */
	xUSBInterruptQueue = xQueueCreate( usbQUEUE_LENGTH + 1, sizeof( xISRStatus * ) );
	
	/* Create the queues used to hold Rx and Tx characters. */
	xRxCDC = xQueueCreate( USB_CDC_QUEUE_SIZE, ( unsigned portCHAR ) sizeof( signed portCHAR ) );
	xTxCDC = xQueueCreate( USB_CDC_QUEUE_SIZE + 1, ( unsigned portCHAR ) sizeof( signed portCHAR ) );

	if( (!xUSBInterruptQueue) || (!xRxCDC) || (!xTxCDC) )
	{	
		/* Not enough RAM to create queues!. */
		return;
	}
	
	/* Initialise a few state variables. */
	pxControlTx.ulNextCharIndex = ( unsigned portLONG ) 0;
	pxControlRx.ulNextCharIndex = ( unsigned portLONG ) 0;
	ucUSBConfig = ( unsigned portCHAR ) 0;
	eDriverState = eNOTHING;
	ucControlState = 0;
	uiCurrentBank = AT91C_UDP_RX_DATA_BK0;


	/* HARDWARE SETUP */

	/* Set the PLL USB Divider */
	AT91C_BASE_CKGR->CKGR_PLLR |= AT91C_CKGR_USBDIV_1;

	/* Enables the 48MHz USB clock UDPCK and System Peripheral USB Clock. */
	AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_UDP;
	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_UDP);

	/* Setup the PIO for the USB pull up resistor. */
	AT91C_BASE_PIOA->PIO_PER = AT91C_PIO_PA16;
	AT91C_BASE_PIOA->PIO_OER = AT91C_PIO_PA16;


	/* Start without the pullup - this will get set at the end of this 
	function. */
   	AT91C_BASE_PIOA->PIO_SODR = AT91C_PIO_PA16;


	/* When using the USB debugger the peripheral registers do not always get
	set to the correct default values.  To make sure set the relevant registers
	manually here. */
	AT91C_BASE_UDP->UDP_IDR = ( unsigned portLONG ) 0xffffffff;
	AT91C_BASE_UDP->UDP_ICR = ( unsigned portLONG ) 0xffffffff;
	AT91C_BASE_UDP->UDP_CSR[ 0 ] = ( unsigned portLONG ) 0x00;
	AT91C_BASE_UDP->UDP_CSR[ 1 ] = ( unsigned portLONG ) 0x00;
	AT91C_BASE_UDP->UDP_CSR[ 2 ] = ( unsigned portLONG ) 0x00;
	AT91C_BASE_UDP->UDP_CSR[ 3 ] = ( unsigned portLONG ) 0x00;
	AT91C_BASE_UDP->UDP_GLBSTATE = 0;
	AT91C_BASE_UDP->UDP_FADDR = 0;

	/* Enable the transceiver. */
	AT91C_UDP_TRANSCEIVER_ENABLE = 0;

	/* Enable the USB interrupts - other interrupts get enabled as the 
	enumeration process progresses. */
	AT91F_AIC_ConfigureIt( AT91C_ID_UDP, usbINTERRUPT_PRIORITY, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, ( void (*)( void ) ) vUSB_ISR_Wrapper );
	AT91C_BASE_AIC->AIC_IECR = 0x1 << AT91C_ID_UDP;


	/* Wait a short while before making our presence known. */
	vTaskDelay( usbINIT_DELAY );
	AT91C_BASE_PIOA->PIO_CODR = AT91C_PIO_PA16;
}
/*-----------------------------------------------------------*/

static void prvSendControlData( unsigned portCHAR *pucData, unsigned portSHORT usRequestedLength, unsigned portLONG ulLengthToSend, portLONG lSendingDescriptor )
{
	if( ( ( unsigned portLONG ) usRequestedLength < ulLengthToSend ) )
	{
		/* Cap the data length to that requested. */
		ulLengthToSend = ( unsigned portSHORT ) usRequestedLength;
	}
	else if( ( ulLengthToSend < ( unsigned portLONG ) usRequestedLength ) && lSendingDescriptor )
	{
		/* We are sending a descriptor.  If the descriptor is an exact 
		multiple of the FIFO length then it will have to be terminated
		with a NULL packet.  Set the state to indicate this if
		necessary. */
		if( ( ulLengthToSend % usbFIFO_LENGTH ) == 0 )
		{
			eDriverState = eSENDING_EVEN_DESCRIPTOR;
		}
	}

	/* Here we assume that the previous message has been sent.  THERE IS NO
	BUFFER OVERFLOW PROTECTION HERE.

	Copy the data to send into the buffer as we cannot send it all at once
	(if it is greater than 8 bytes in length). */
	memcpy( pxControlTx.ucBuffer, pucData, ulLengthToSend );

	/* Reinitialise the buffer index so we start sending from the start of 
	the data. */
	pxControlTx.ulTotalDataLength = ulLengthToSend;
	pxControlTx.ulNextCharIndex = ( unsigned portLONG ) 0;

	/* Send the first 8 bytes now.  The rest will get sent in response to 
	TXCOMP interrupts. */
	prvSendNextSegment();
}
/*-----------------------------------------------------------*/

static void prvSendNextSegment( void )
{
volatile unsigned portLONG ulNextLength, ulStatus, ulLengthLeftToSend;

	/* Is there any data to send? */
	if( pxControlTx.ulTotalDataLength > pxControlTx.ulNextCharIndex )
	{
		ulLengthLeftToSend = pxControlTx.ulTotalDataLength - pxControlTx.ulNextCharIndex;
	
		/* We can only send 8 bytes to the fifo at a time. */
		if( ulLengthLeftToSend > usbFIFO_LENGTH )
		{
			ulNextLength = usbFIFO_LENGTH;
		}
		else
		{
			ulNextLength = ulLengthLeftToSend;
		}

		/* Wait until we can place data in the fifo.  THERE IS NO TIMEOUT
		HERE! */
		while( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_TXPKTRDY )
		{
			vTaskDelay( usbSHORTEST_DELAY );
		}

		/* Write the data to the FIFO. */
		while( ulNextLength > ( unsigned portLONG ) 0 )
		{
			AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_0 ] = pxControlTx.ucBuffer[ pxControlTx.ulNextCharIndex ];
	
			ulNextLength--;
			pxControlTx.ulNextCharIndex++;
		}
	
		/* Start the transmission. */
		portENTER_CRITICAL();
		{
			ulStatus = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];
			usbCSR_SET_BIT( &ulStatus, ( ( unsigned portLONG ) 0x10 ) );
			AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulStatus;
		}
		portEXIT_CRITICAL();
	}
	else
	{
		/* There is no data to send.  If we were sending a descriptor and the 
		descriptor was an exact multiple of the max packet size then we need
		to send a null to terminate the transmission. */
		if( eDriverState == eSENDING_EVEN_DESCRIPTOR )
		{
			prvSendZLP();
			eDriverState = eNOTHING;
		}
	}
}