FreeRTOS/Demo/ColdFire_MCF52259_CodeWarrior/FreeRTOS_Tick_Setup.c

/*
 * FreeRTOS Kernel V10.3.0
 * 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!
 */

#include "FreeRTOS.h"
#include "task.h"

__declspec(interrupt:0) void vPIT0InterruptHandler( void );

/* Constants used to configure the interrupts. */
#define portPRESCALE_VALUE			64
#define portPRESCALE_REG_SETTING	( 5 << 8 )
#define portPIT_INTERRUPT_ENABLED	( 0x08 )
#define configPIT0_INTERRUPT_VECTOR	( 55 )

/*
 * FreeRTOS.org requires two interrupts - a tick interrupt generated from a
 * timer source, and a spare interrupt vector used for context switching.
 * The configuration below uses PIT0 for the former, and vector 16 for the
 * latter.  **IF YOUR APPLICATION HAS BOTH OF THESE INTERRUPTS FREE THEN YOU DO
 * NOT NEED TO CHANGE ANY OF THIS CODE** - otherwise instructions are provided
 * here for using alternative interrupt sources.
 *
 * To change the tick interrupt source:
 *
 *	1) Modify vApplicationSetupInterrupts() below to be correct for whichever
 *	peripheral is to be used to generate the tick interrupt.  The name of the
 *  handler function (currently vPIT0InterruptHandler()) should also be updated
 *  to indicate which peripheral is generating the interrupt.
 *
 *	2) Make sure the interrupt source is cleared within the interrupt handler function.
 *  Currently vPIT0InterruptHandler() clears the PIT0 interrupt.
 *
 *  3) Update the vector table within mcf5225x_vectors.s to install the tick
 *  interrupt handler in the correct vector position.
 *
 * To change the spare interrupt source:
 *
 *  1) Modify vApplicationSetupInterrupts() below to be correct for whichever
 *  interrupt vector is to be used.  Make sure you use a spare interrupt on interrupt
 *  controller 0, otherwise the register used to request context switches will also
 *  require modification.
 *
 *  2) Change the definition of configYIELD_INTERRUPT_VECTOR within FreeRTOSConfig.h
 *  to be correct for your chosen interrupt vector.
 *
 *  3) Update the vector table within mcf5225x_vectors.s to install the handler
 *  _vPortYieldISR() in the correct vector position (by default vector number 16 is
 *  used).
 */
void vApplicationSetupInterrupts( void )
{
const unsigned short usCompareMatchValue = ( ( configCPU_CLOCK_HZ / portPRESCALE_VALUE ) / configTICK_RATE_HZ );

    /* Configure interrupt priority and level and unmask interrupt for PIT0. */
    MCF_INTC0_ICR55 = ( 1 | ( configKERNEL_INTERRUPT_PRIORITY << 3 ) );
    MCF_INTC0_IMRH &= ~( MCF_INTC_IMRH_INT_MASK55 );

    /* Do the same for vector 63 (interrupt controller 0.  I don't think the
    write to MCF_INTC0_IMRH is actually required here but is included for
    completeness. */
    MCF_INTC0_ICR16 = ( 0 | configKERNEL_INTERRUPT_PRIORITY << 3 );
    MCF_INTC0_IMRL &= ~( MCF_INTC_IMRL_INT_MASK16 | 0x01 );

    /* Configure PIT0 to generate the RTOS tick. */
    MCF_PIT0_PCSR |= MCF_PIT_PCSR_PIF;
    MCF_PIT0_PCSR = ( portPRESCALE_REG_SETTING | MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_EN );
	MCF_PIT0_PMR = usCompareMatchValue;
}
/*-----------------------------------------------------------*/

__declspec(interrupt:0) void vPIT0InterruptHandler( void )
{
unsigned long ulSavedInterruptMask;

	/* Clear the PIT0 interrupt. */
	MCF_PIT0_PCSR |= MCF_PIT_PCSR_PIF;

	/* Increment the RTOS tick. */
	ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
		if( xTaskIncrementTick() != pdFALSE )
		{
			taskYIELD();
		}
	portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
}