199 lines
6.6 KiB
C
199 lines
6.6 KiB
C
/*
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FreeRTOS.org V4.7.1 - Copyright (C) 2003-2008 Richard Barry.
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This file is part of the FreeRTOS.org distribution.
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FreeRTOS.org is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS.org, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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Please ensure to read the configuration and relevant port sections of the
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online documentation.
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+++ http://www.FreeRTOS.org +++
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Documentation, latest information, license and contact details.
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+++ http://www.SafeRTOS.com +++
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A version that is certified for use in safety critical systems.
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+++ http://www.OpenRTOS.com +++
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Commercial support, development, porting, licensing and training services.
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***************************************************************************
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the PIC32MX port.
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*----------------------------------------------------------*/
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* Hardware specifics. */
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#define portTIMER_PRESCALE 8
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/* Bits within various registers. */
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#define portIE_BIT ( 0x00000001 )
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#define portEXL_BIT ( 0x00000002 )
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#define portIPL_SHIFT ( 10 )
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#define portALL_IPL_BITS ( 0x1f << portIPL_SHIFT )
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/* The EXL bit is set to ensure interrupts do not occur while the context of
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the first task is being restored. */
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#define portINITIAL_SR ( portIE_BIT | portEXL_BIT )
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/* Records the nesting depth of calls to portENTER_CRITICAL(). */
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unsigned portBASE_TYPE uxCriticalNesting = 0x55555555;
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/* The stack used by interrupt service routines that cause a context switch. */
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portSTACK_TYPE xISRStack[ configISR_STACK_SIZE ] = { 0 };
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/* The top of stack value ensures there is enough space to store 6 registers on
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the callers stack, as some functions seem to want to do this. */
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const portBASE_TYPE * const xISRStackTop = &( xISRStack[ configISR_STACK_SIZE - 7 ] );
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/* Place the prototype here to ensure the interrupt vector is correctly installed. */
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extern void __attribute__( (interrupt(ipl1), vector(_TIMER_1_VECTOR))) vT1InterruptHandler( void );
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/*
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* General exception handler that will be called for all general exceptions
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* other than SYS. This should be overridden by a user provided handler.
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*/
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void vApplicationGeneralExceptionHandler( unsigned portLONG ulCause, unsigned portLONG ulStatus ) __attribute__((weak));
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/*-----------------------------------------------------------*/
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/*
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* See header file for description.
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*/
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portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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{
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*pxTopOfStack = (portSTACK_TYPE) 0xDEADBEEF;
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pxTopOfStack--;
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*pxTopOfStack = (portSTACK_TYPE) 0x12345678; /* Word to which the stack pointer will be left pointing after context restore. */
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pxTopOfStack--;
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*pxTopOfStack = (portSTACK_TYPE) _CP0_GET_CAUSE();
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pxTopOfStack--;
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*pxTopOfStack = (portSTACK_TYPE) portINITIAL_SR; /* CP0_STATUS */
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pxTopOfStack--;
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*pxTopOfStack = (portSTACK_TYPE) pxCode; /* CP0_EPC */
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pxTopOfStack--;
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*pxTopOfStack = (portSTACK_TYPE) NULL; /* ra */
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pxTopOfStack -= 15;
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*pxTopOfStack = (portSTACK_TYPE) pvParameters; /* Parameters to pass in */
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pxTopOfStack -= 14;
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*pxTopOfStack = (portSTACK_TYPE) 0x00000000; /* critical nesting level */
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pxTopOfStack--;
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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/*
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* Setup a timer for a regular tick.
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*/
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void prvSetupTimerInterrupt( void )
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{
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const unsigned portLONG ulCompareMatch = (configPERIPHERAL_CLOCK_HZ / portTIMER_PRESCALE) / configTICK_RATE_HZ;
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OpenTimer1( ( T1_ON | T1_PS_1_8 | T1_SOURCE_INT ), ulCompareMatch );
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ConfigIntTimer1( T1_INT_ON | configKERNEL_INTERRUPT_PRIORITY );
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler(void)
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{
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/* It is unlikely that the scheduler for the PIC port will get stopped
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once running. If required disable the tick interrupt here, then return
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to xPortStartScheduler(). */
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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void vPortEnterCritical(void)
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{
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unsigned portLONG ulStatus;
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/* Mask interrupts at and below the kernel interrupt priority. */
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ulStatus = _CP0_GET_STATUS();
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ulStatus |= ( configKERNEL_INTERRUPT_PRIORITY << portIPL_SHIFT );
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_CP0_SET_STATUS( ulStatus );
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/* Once interrupts are disabled we can access the nesting count directly. */
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uxCriticalNesting++;
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}
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/*-----------------------------------------------------------*/
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void vPortExitCritical(void)
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{
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unsigned portLONG ulStatus;
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/* If we are in a critical section then we can access the nesting count
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directly. */
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uxCriticalNesting--;
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/* Has the nesting unwound? */
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if( uxCriticalNesting == 0 )
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{
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/* Unmask all interrupts. */
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ulStatus = _CP0_GET_STATUS();
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ulStatus &= ~portALL_IPL_BITS;
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_CP0_SET_STATUS( ulStatus );
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}
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xPortStartScheduler( void )
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{
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extern void vPortStartFirstTask( void );
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/* Setup the timer to generate the tick. Interrupts will have been
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disabled by the time we get here. */
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prvSetupTimerInterrupt();
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/* Kick off the highest priority task that has been created so far. */
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vPortStartFirstTask();
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/* Should never get here as the tasks will now be executing. */
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return pdFALSE;
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}
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/*-----------------------------------------------------------*/
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void vApplicationGeneralExceptionHandler( unsigned portLONG ulCause, unsigned portLONG ulStatus )
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{
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/* This function is declared weak and should be overridden by the users
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application. */
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while( 1 );
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}
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