sam7_emac_isr.c

FreeRTOSV4.1.0 安裝文件 FreeRTOS 是一个源码公开的免费的嵌入式实时操作系统

/*
	FreeRTOS.org V4.1.0 - Copyright (C) 2003-2006 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.

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	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

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	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section
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	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license
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*/

/* 
Changes from V3.2.4

	+ Also read the EMAC_RSR register in the EMAC ISR as a work around the 
	  the EMAC bug that can reset the RX bit in EMAC_ISR register before the
	  bit has been read.

Changes from V4.0.1

	+ Only check the interrupt status register to see if an EMAC Tx interrupt
	  has occurred.  Previously the TSR register was also inspected.
*/

#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
#include "SAM7_EMAC.h"
#include "AT91SAM7X256.h"

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

/* The semaphore used to signal the arrival of new data to the interface
task. */
static xSemaphoreHandle xSemaphore = NULL;

void vEMACISR( void ) __attribute__((naked));

/*-----------------------------------------------------------*/
/*
 * The EMAC ISR.  Handles both Tx and Rx complete interrupts.
 */
void vEMACISR( void )
{
	/* This ISR can cause a context switch, so the first statement must be a
	call to the portENTER_SWITCHING_ISR() macro.  This must be BEFORE any
	variable declarations. */
	portENTER_SWITCHING_ISR();

	/* Variable definitions can be made now. */
	volatile unsigned portLONG ulIntStatus, ulEventStatus;
	portBASE_TYPE xSwitchRequired = pdFALSE;
    extern void vClearEMACTxBuffer( void );

	/* Find the cause of the interrupt. */
	ulIntStatus = AT91C_BASE_EMAC->EMAC_ISR;
	ulEventStatus = AT91C_BASE_EMAC->EMAC_RSR;

	if( ( ulIntStatus & AT91C_EMAC_RCOMP ) || ( ulEventStatus & AT91C_EMAC_REC ) )
	{
		/* A frame has been received, signal the lwIP task so it can process
		the Rx descriptors. */
		xSwitchRequired = xSemaphoreGiveFromISR( xSemaphore, pdFALSE );
		AT91C_BASE_EMAC->EMAC_RSR = AT91C_EMAC_REC;
	}

	if( ulIntStatus & AT91C_EMAC_TCOMP )
	{
		/* A frame has been transmitted.  Mark all the buffers used by the
		frame just transmitted as free again. */
		vClearEMACTxBuffer();
		AT91C_BASE_EMAC->EMAC_TSR = AT91C_EMAC_COMP;
	}

	/* Clear the interrupt. */
	AT91C_BASE_AIC->AIC_EOICR = 0;

	/* If a task was woken by either a frame being received then we may need to 
	switch to another task. */
	portEXIT_SWITCHING_ISR( xSwitchRequired );
}
/*-----------------------------------------------------------*/

void vPassEMACSemaphore( xSemaphoreHandle xCreatedSemaphore )
{
	/* Simply store the semaphore that should be used by the ISR. */
	xSemaphore = xCreatedSemaphore;
}