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/*

    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.

    ***************************************************************************

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    ***************************************************************************

    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.

    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 and the FreeRTOS license exception along with FreeRTOS; if not it

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    by writing to Richard Barry, contact details for whom are available on the

    FreeRTOS WEB site.

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*/

/*

  BASIC INTERRUPT DRIVEN DRIVER FOR USB.

  This file contains all the usb components that must be compiled

  to ARM mode.  The components that can be compiled to either ARM or THUMB

  mode are contained in USB-CDC.c.

*/

/* Scheduler includes. */

#include "FreeRTOS.h"

#include "task.h"

#include "queue.h"

/* Demo application includes. */

#include "Board.h"

#include "usb.h"

#include "USB-CDC.h"

#define usbINT_CLEAR_MASK       (AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT | AT91C_UDP_RXSETUP | AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1 )

/*-----------------------------------------------------------*/

/* Messages and queue used to communicate between the ISR and the USB task. */

static xISRStatus xISRMessages[ usbQUEUE_LENGTH + 1 ];

extern xQueueHandle xUSBInterruptQueue;

/*-----------------------------------------------------------*/

/* The ISR can cause a context switch so is declared naked. */

void vUSB_ISR_Wrapper( void ) __attribute__ ((naked));

/* The function that actually performs the ISR work.  This must be separate

from the wrapper function to ensure the correct stack frame gets set up. */

void vUSB_ISR_Handler( void );

/*-----------------------------------------------------------*/

void vUSB_ISR_Handler( void )

{

portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

static volatile unsigned long ulNextMessage = 0;

xISRStatus *pxMessage;

unsigned long ulRxBytes;

unsigned char ucFifoIndex;

    /* Use the next message from the array. */

        pxMessage = &( xISRMessages[ ( ulNextMessage & usbQUEUE_LENGTH ) ] );

        ulNextMessage++;

    /* Save UDP ISR state for task-level processing. */

        pxMessage->ulISR = AT91C_BASE_UDP->UDP_ISR;

        pxMessage->ulCSR0 = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];

    /* Clear interrupts from ICR. */

        AT91C_BASE_UDP->UDP_ICR = AT91C_BASE_UDP->UDP_IMR | AT91C_UDP_ENDBUSRES;

        /* Process incoming FIFO data.  Must set DIR (if needed) and clear RXSETUP

        before exit. */

    /* Read CSR and get incoming byte count. */

        ulRxBytes = ( pxMessage->ulCSR0 >> 16 ) & usbRX_COUNT_MASK;

        /* Receive control transfers on endpoint 0. */

        if( pxMessage->ulCSR0 & ( AT91C_UDP_RXSETUP | AT91C_UDP_RX_DATA_BK0 ) )

        {

                /* Save FIFO data buffer for either a SETUP or DATA stage */

                for( ucFifoIndex = 0; ucFifoIndex < ulRxBytes; ucFifoIndex++ )

                {

                        pxMessage->ucFifoData[ ucFifoIndex ] = AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_0 ];

                }

                /* Set direction for data stage.  Must be done before RXSETUP is

                cleared. */

                if( ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RXSETUP ) )

                {

                        if( ulRxBytes && ( pxMessage->ucFifoData[ usbREQUEST_TYPE_INDEX ] & 0x80 ) )

                        {

                                AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] |= AT91C_UDP_DIR;

                                /* Might not be wise in an ISR! */

                                while( !(AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_DIR) );

                        }

                        /* Clear RXSETUP */

                        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~AT91C_UDP_RXSETUP;

                        /* Might not be wise in an ISR! */

                        while ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RXSETUP );

                }

                else

                {

                   /* Clear RX_DATA_BK0 */

                   AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~AT91C_UDP_RX_DATA_BK0;

                   /* Might not be wise in an ISR! */

                   while ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RX_DATA_BK0 );

                }

        }

        /* If we received data on endpoint 1, disable its interrupts until it is

        processed in the main loop */

        if( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] & ( AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1 ) )

        {

                AT91C_BASE_UDP->UDP_IDR = AT91C_UDP_EPINT1;

        }

        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~( AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT );

        /* Clear interrupts for the other endpoints, retain data flags for endpoint

        1. */

        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] &= ~( AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT | AT91C_UDP_RXSETUP );

        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ] &= ~usbINT_CLEAR_MASK;

        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_3 ] &= ~usbINT_CLEAR_MASK;

        /* Post ISR data to queue for task-level processing */

        xQueueSendFromISR( xUSBInterruptQueue, &pxMessage, &xHigherPriorityTaskWoken );

        /* Clear AIC to complete ISR processing */

        AT91C_BASE_AIC->AIC_EOICR = 0;

        /* Do a task switch if needed */

        if( xHigherPriorityTaskWoken )

        {

                /* This call will ensure that the unblocked task will be executed

                immediately upon completion of the ISR if it has a priority higher

                than the interrupted task. */

                portYIELD_FROM_ISR();

        }

}

/*-----------------------------------------------------------*/

void vUSB_ISR_Wrapper( void )

{

        /* Save the context of the interrupted task. */

        portSAVE_CONTEXT();

        /* Call the handler to do the work.  This must be a separate

        function to ensure the stack frame is set up correctly. */

        vUSB_ISR_Handler();

        /* Restore the context of whichever task will execute next. */

        portRESTORE_CONTEXT();

}