/*
 * FreeRTOS Kernel V10.4.1
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

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

/* Constants required for interrupt management. */
#define tcpCLEAR_VIC_INTERRUPT	( 0 )
#define tcpEINT0_VIC_CHANNEL_BIT	( ( unsigned long ) 0x4000 )

/* EINT0 interrupt handler.  This processes interrupts from the WIZnet device. */
void vEINT0_ISR_Wrapper( void ) __attribute__((naked));

/* The handler that goes with the EINT0 wrapper. */
void vEINT0_ISR_Handler( void );

/* Variable is required for its address, but does not otherwise get used. */
static long lDummyVariable;

/*
 * When the WIZnet device asserts an interrupt we send an (empty) message to
 * the TCP task.  This wakes the task so the interrupt can be processed.  The
 * source of the interrupt has to be ascertained by the TCP task as this 
 * requires an I2C transaction which cannot be performed from this ISR.
 * Note this code predates the introduction of semaphores, a semaphore should
 * be used in place of the empty queue message.
 */
void vEINT0_ISR_Handler( void )
{
extern QueueHandle_t xTCPISRQueue;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* Just wake the TCP task so it knows an ISR has occurred. */
	xQueueSendFromISR( xTCPISRQueue, ( void * ) &lDummyVariable, &xHigherPriorityTaskWoken );	

	/* We cannot carry on processing interrupts until the TCP task has 
	processed this one - so for now interrupts are disabled.  The TCP task will
	re-enable it. */
	VICIntEnClear |= tcpEINT0_VIC_CHANNEL_BIT;

	/* Clear the interrupt bit. */	
	VICVectAddr = tcpCLEAR_VIC_INTERRUPT;

	if( xHigherPriorityTaskWoken )
	{
		portYIELD_FROM_ISR();
	}
}
/*-----------------------------------------------------------*/

void vEINT0_ISR_Wrapper( void )
{
	/* Save the context of the interrupted task. */
	portSAVE_CONTEXT();

	/* The handler must be a separate function from the wrapper to
	ensure the correct stack frame is set up. */
	vEINT0_ISR_Handler();

	/* Restore the context of whichever task is going to run next. */
	portRESTORE_CONTEXT();
}