Demo/ARM7_AT91SAM7X256_Eclipse/RTOSDemo/USB/USB_ISR.c

/*
	FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org 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.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section 
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

    ***************************************************************************
    ***************************************************************************
    *                                                                         *
    * Get the FreeRTOS eBook!  See http://www.FreeRTOS.org/Documentation      *
	*                                                                         *
	* This is a concise, step by step, 'hands on' guide that describes both   *
	* general multitasking concepts and FreeRTOS specifics. It presents and   *
	* explains numerous examples that are written using the FreeRTOS API.     *
	* Full source code for all the examples is provided in an accompanying    *
	* .zip file.                                                              *
    *                                                                         *
    ***************************************************************************
    ***************************************************************************

	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.
*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

/* Demo app includes. */
#include "USBSample.h"

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

#define usbCSR_CLEAR_BIT( pulValueNow, ulBit )											\
{																						\
	/* Set TXCOMP, RX_DATA_BK0, RXSETUP, */												\
	/* STALLSENT and RX_DATA_BK1 to 1 so the */											\
	/* write has no effect. */															\
	( * ( ( unsigned portLONG * ) pulValueNow ) ) |= ( unsigned portLONG ) 0x4f;		\
																						\
	/* Clear the FORCE_STALL and TXPKTRDY bits */										\
	/* so the write has no effect. */													\
	( * ( ( unsigned portLONG * ) pulValueNow ) ) &= ( unsigned portLONG ) 0xffffffcf;	\
																						\
	/* Clear whichever bit we want clear. */											\
	( * ( ( unsigned portLONG * ) pulValueNow ) ) &= ( ~ulBit );						\
}


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

/*
 * ISR entry point.
 */

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

/*
 * Actual ISR handler.  This must be separate from the entry point as the stack
 * is used.
 */
void vUSB_ISR_Handler( void );

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

/* Array in which the USB interrupt status is passed between the ISR and task. */
static xISRStatus xISRMessages[ usbQUEUE_LENGTH + 1 ];

/* Queue used to pass messages between the ISR and the task. */
extern xQueueHandle xUSBInterruptQueue; 

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

void vUSB_ISR_Handler( void )
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; 
static volatile unsigned portLONG ulNextMessage = 0;
xISRStatus *pxMessage;
unsigned portLONG ulTemp, ulRxBytes;

	/* To reduce the amount of time spent in this interrupt it would be 
	possible to defer the majority of this processing to an 'interrupt task',
	that is a task that runs at a higher priority than any of the application
	tasks. */

	/* Take the next message from the queue.  Note that usbQUEUE_LENGTH *must*
	be all 1's, as in 0x01, 0x03, 0x07, etc. */
	pxMessage = &( xISRMessages[ ( ulNextMessage & usbQUEUE_LENGTH ) ] );
	ulNextMessage++;

	/* Take a snapshot of the current USB state for processing at the task
	level. */
	pxMessage->ulISR = AT91C_BASE_UDP->UDP_ISR;
	pxMessage->ulCSR0 = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];

	/* Clear the interrupts from the ICR register.  The bus end interrupt is
	cleared separately as it does not appear in the mask register. */
	AT91C_BASE_UDP->UDP_ICR = AT91C_BASE_UDP->UDP_IMR | AT91C_UDP_ENDBUSRES;
	
	/* If there are bytes in the FIFO then we have to retrieve them here.  
	Ideally this would be done at the task level.  However we need to clear the
	RXSETUP interrupt before leaving the ISR, and this may cause the data in
	the FIFO to be overwritten.  Also the DIR bit has to be changed before the
	RXSETUP bit is cleared (as per the SAM7 manual). */
	ulTemp = pxMessage->ulCSR0;
	
	/* Are there any bytes in the FIFO? */
	ulRxBytes = ulTemp >> 16;
	ulRxBytes &= usbRX_COUNT_MASK;
	
	/* With this minimal implementation we are only interested in receiving 
	setup bytes on the control end point. */
	if( ( ulRxBytes > 0 ) && ( ulTemp & AT91C_UDP_RXSETUP ) )
	{
		/* Take off 1 for a zero based index. */
		while( ulRxBytes > 0 )
		{
			ulRxBytes--;
			pxMessage->ucFifoData[ ulRxBytes ] = AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_0 ];			
		}
		
		/* The direction must be changed first. */
		usbCSR_SET_BIT( &ulTemp, ( AT91C_UDP_DIR ) );
		AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulTemp;
	}
	
	/* Must write zero's to TXCOMP, STALLSENT, RXSETUP, and the RX DATA
	registers to clear the interrupts in the CSR register. */
	usbCSR_CLEAR_BIT( &ulTemp, usbINT_CLEAR_MASK );
	AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] = ulTemp;

	/* Also clear the interrupts in the CSR1 register. */
	ulTemp = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ];
	usbCSR_CLEAR_BIT( &ulTemp, usbINT_CLEAR_MASK );	
	AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] = ulTemp;

	/* The message now contains the entire state and optional data from
	the USB interrupt.  This can now be posted on the Rx queue ready for
	processing at the task level. */
	xQueueSendFromISR( xUSBInterruptQueue, &pxMessage, &xHigherPriorityTaskWoken );

	/* We may want to switch to the USB task, if this message has made
	it the highest priority task that is ready to execute. */
	if( xHigherPriorityTaskWoken )
	{
		portYIELD_FROM_ISR();
	}

	/* Clear the AIC ready for the next interrupt. */		
	AT91C_BASE_AIC->AIC_EOICR = 0;
}
/*-----------------------------------------------------------*/

void vUSB_ISR_Wrapper( void )
{
	/* Save the context of the interrupted task. */
	portSAVE_CONTEXT();

	/* Call the handler itself.  This must be a separate function as it uses
	the stack. */
	vUSB_ISR_Handler();

	/* Restore the context of the task that is going to 
	execute next. This might not be the same as the originally 
	interrupted task.*/
	portRESTORE_CONTEXT();
}