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/*
* FreeRTOS Kernel V10.5.1
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* 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.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the NIOS2 port.
*----------------------------------------------------------*/
/* Standard Includes. */
#include <string.h>
#include <errno.h>
/* Altera includes. */
#include "sys/alt_irq.h"
#include "sys/alt_exceptions.h"
#include "altera_avalon_timer_regs.h"
#include "priv/alt_irq_table.h"
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
/* Interrupts are enabled. */
#define portINITIAL_ESTATUS ( StackType_t ) 0x01
int _alt_ic_isr_register(alt_u32 ic_id, alt_u32 irq, alt_isr_func isr,
void *isr_context, void *flags);
/*-----------------------------------------------------------*/
/*
* Setup the timer to generate the tick interrupts.
*/
static void prvSetupTimerInterrupt( void );
/*
* Call back for the alarm function.
*/
void vPortSysTickHandler( void * context);
/*-----------------------------------------------------------*/
static void prvReadGp( uint32_t *ulValue )
{
asm( "stw gp, (%0)" :: "r"(ulValue) );
}
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
StackType_t *pxFramePointer = pxTopOfStack - 1;
StackType_t xGlobalPointer;
prvReadGp( &xGlobalPointer );
/* End of stack marker. */
*pxTopOfStack = 0xdeadbeef;
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) pxFramePointer;
pxTopOfStack--;
*pxTopOfStack = xGlobalPointer;
/* Space for R23 to R16. */
pxTopOfStack -= 9;
*pxTopOfStack = ( StackType_t ) pxCode;
pxTopOfStack--;
*pxTopOfStack = portINITIAL_ESTATUS;
/* Space for R15 to R5. */
pxTopOfStack -= 12;
*pxTopOfStack = ( StackType_t ) pvParameters;
/* Space for R3 to R1, muldiv and RA. */
pxTopOfStack -= 5;
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
BaseType_t xPortStartScheduler( void )
{
/* Start the timer that generates the tick ISR. Interrupts are disabled
here already. */
prvSetupTimerInterrupt();
/* Start the first task. */
asm volatile ( " movia r2, restore_sp_from_pxCurrentTCB \n"
" jmp r2 " );
/* Should not get here! */
return 0;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
/* It is unlikely that the NIOS2 port will require this function as there
is nothing to return to. */
}
/*-----------------------------------------------------------*/
/*
* Setup the systick timer to generate the tick interrupts at the required
* frequency.
*/
void prvSetupTimerInterrupt( void )
{
/* Try to register the interrupt handler. */
if ( -EINVAL == _alt_ic_isr_register( SYS_CLK_IRQ_INTERRUPT_CONTROLLER_ID, SYS_CLK_IRQ, vPortSysTickHandler, 0x0, 0x0 ) )
{
/* Failed to install the Interrupt Handler. */
asm( "break" );
}
else
{
/* Configure SysTick to interrupt at the requested rate. */
IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_STOP_MSK );
IOWR_ALTERA_AVALON_TIMER_PERIODL( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) & 0xFFFF );
IOWR_ALTERA_AVALON_TIMER_PERIODH( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) >> 16 );
IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_CONT_MSK | ALTERA_AVALON_TIMER_CONTROL_START_MSK | ALTERA_AVALON_TIMER_CONTROL_ITO_MSK );
}
/* Clear any already pending interrupts generated by the Timer. */
IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
}
/*-----------------------------------------------------------*/
void vPortSysTickHandler( void * context)
{
/* Increment the kernel tick. */
if( xTaskIncrementTick() != pdFALSE )
{
vTaskSwitchContext();
}
/* Clear the interrupt. */
IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
}
/*-----------------------------------------------------------*/
/** This function is a re-implementation of the Altera provided function.
* The function is re-implemented to prevent it from enabling an interrupt
* when it is registered. Interrupts should only be enabled after the FreeRTOS.org
* kernel has its scheduler started so that contexts are saved and switched
* correctly.
*/
int _alt_ic_isr_register(alt_u32 ic_id, alt_u32 irq, alt_isr_func isr,
void *isr_context, void *flags)
{
int rc = -EINVAL;
alt_irq_context status;
int id = irq; /* IRQ interpreted as the interrupt ID. */
if (id < ALT_NIRQ)
{
/*
* interrupts are disabled while the handler tables are updated to ensure
* that an interrupt doesn't occur while the tables are in an inconsistant
* state.
*/
status = alt_irq_disable_all ();
alt_irq[id].handler = isr;
alt_irq[id].context = isr_context;
rc = (isr) ? alt_ic_irq_enable(ic_id, id) : alt_ic_irq_disable(ic_id, id);
/* alt_irq_enable_all(status); This line is removed to prevent the interrupt from being immediately enabled. */
}
return rc;
}
/*-----------------------------------------------------------*/
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