git.sur5r.net Git - freertos/blob - Source/portable/GCC/CORTUS_APS3/port.c

   1 /*
   2     FreeRTOS V6.0.4 - Copyright (C) 2010 Real Time Engineers Ltd.
   3
   4     ***************************************************************************
   5     *                                                                         *
   6     * If you are:                                                             *
   7     *                                                                         *
   8     *    + New to FreeRTOS,                                                   *
   9     *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
  10     *    + Looking for basic training,                                        *
  11     *    + Wanting to improve your FreeRTOS skills and productivity           *
  12     *                                                                         *
  13     * then take a look at the FreeRTOS eBook                                  *
  14     *                                                                         *
  15     *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
  16     *                  http://www.FreeRTOS.org/Documentation                  *
  17     *                                                                         *
  18     * A pdf reference manual is also available.  Both are usually delivered   *
  19     * to your inbox within 20 minutes to two hours when purchased between 8am *
  20     * and 8pm GMT (although please allow up to 24 hours in case of            *
  21     * exceptional circumstances).  Thank you for your support!                *
  22     *                                                                         *
  23     ***************************************************************************
  24
  25     This file is part of the FreeRTOS distribution.
  26
  27     FreeRTOS is free software; you can redistribute it and/or modify it under
  28     the terms of the GNU General Public License (version 2) as published by the
  29     Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
  30     ***NOTE*** The exception to the GPL is included to allow you to distribute
  31     a combined work that includes FreeRTOS without being obliged to provide the
  32     source code for proprietary components outside of the FreeRTOS kernel.
  33     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
  34     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  35     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  36     more details. You should have received a copy of the GNU General Public
  37     License and the FreeRTOS license exception along with FreeRTOS; if not it
  38     can be viewed here: http://www.freertos.org/a00114.html and also obtained
  39     by writing to Richard Barry, contact details for whom are available on the
  40     FreeRTOS WEB site.
  41
  42     1 tab == 4 spaces!
  43
  44     http://www.FreeRTOS.org - Documentation, latest information, license and
  45     contact details.
  46
  47     http://www.SafeRTOS.com - A version that is certified for use in safety
  48     critical systems.
  49
  50     http://www.OpenRTOS.com - Commercial support, development, porting,
  51     licensing and training services.
  52 */
  53
  54 /* Standard includes. */
  55 #include <stdlib.h>
  56
  57 /* Kernel includes. */
  58 #include "FreeRTOS.h"
  59 #include "task.h"
  60
  61 /* Machine includes */
  62 #include <machine/counter.h>
  63 #include <machine/ic.h>
  64 /*-----------------------------------------------------------*/
  65
  66 /* The initial PSR has the Previous Interrupt Enabled (PIEN) flag set. */
  67 #define portINITIAL_PSR                 ( 0x00020000 )
  68
  69 /*-----------------------------------------------------------*/
  70
  71 /*
  72  * Perform any hardware configuration necessary to generate the tick interrupt.
  73  */
  74 static void prvSetupTimerInterrupt( void );
  75 /*-----------------------------------------------------------*/
  76
  77 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE * pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
  78 {
  79         /* For the time being, mimic the stack when using the
  80         __attribute__((interrupt)) plus the extra caller saved registers. */
  81         This leaves a buffer of two works unused. */
  82         pxTopOfStack -= 18;
  83
  84         /* RTT */
  85         pxTopOfStack[ 16 ] = ( portSTACK_TYPE )pxCode;
  86
  87         /* PSR */
  88         pxTopOfStack[ 15 ] = portINITIAL_PSR;
  89
  90         /* R14 and R15 aka FuncSP and LR, respectively */
  91         pxTopOfStack[ 14 ] = 0x00000000;
  92         pxTopOfStack[ 13 ] = ( portSTACK_TYPE )( pxTopOfStack + 17 );
  93
  94         /* R7 to R2 */
  95         pxTopOfStack[ 12 ] = 0x07070707;
  96         pxTopOfStack[ 11 ] = 0x06060606;
  97         pxTopOfStack[ 10 ] = 0x05050505;
  98         pxTopOfStack[ 9 ] = 0x04040404;
  99         pxTopOfStack[ 8 ] = 0x03030303;
 100         pxTopOfStack[ 7 ] = ( portSTACK_TYPE )pvParameters;
 101
 102         /* Set the Interrupt Priority on Task entry. */
 103         pxTopOfStack[ 6 ] = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
 104
 105         /* R13 to R8. */
 106         pxTopOfStack[ 5 ] = 0x0D0D0D0D;
 107         pxTopOfStack[ 4 ] = 0x0C0C0C0C;
 108         pxTopOfStack[ 3 ] = 0x0B0B0B0B;
 109         pxTopOfStack[ 2 ] = 0x0A0A0A0A;
 110         pxTopOfStack[ 1 ] = 0x09090909;
 111         pxTopOfStack[ 0 ] = 0x08080808;
 112
 113         return pxTopOfStack;
 114 }
 115 /*-----------------------------------------------------------*/
 116
 117 portBASE_TYPE xPortStartScheduler( void )
 118 {
 119         /* Set-up the timer interrupt. */
 120         prvSetupTimerInterrupt();
 121
 122         /* Enable the TRAP yield. */
 123         irq[ portIRQ_TRAP_YIELD ].ien = 1;
 124         irq[ portIRQ_TRAP_YIELD ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
 125
 126         /* Integrated Interrupt Controller: Enable all interrupts. */
 127         ic->ien = 1;
 128
 129         /* Restore callee saved registers. */
 130         portRESTORE_CONTEXT();
 131
 132         /* Mimic an ISR epilogue to start the task executing. */
 133         asm __volatile__(                                               \
 134                 "ldd    r6, [r1]+0x20                   \n"     \
 135                 "mov    psr, r6                                 \n"     \
 136                 "mov    rtt, r7                                 \n"     \
 137                 "ldd    r14, [r1]+0x18                  \n"     \
 138                 "ldq    r4, [r1]+0x8                    \n"     \
 139                 "ldd    r2, [r1]                                \n"     \
 140                 "add    r1, #0x28                               \n"     \
 141                 "rti                                                    \n"     \
 142                 );                                                                      \
 143
 144         /* Should not get here. */
 145         return 0;
 146 }
 147 /*-----------------------------------------------------------*/
 148
 149 static void prvSetupTimerInterrupt( void )
 150 {
 151         /* Enable timer interrupts */
 152         counter1->reload = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1;
 153         counter1->value = counter1->reload;
 154         counter1->mask = 1;
 155
 156         /* Set the IRQ Handler priority and enable it. */
 157         irq[ IRQ_COUNTER1 ].ien = 1;
 158         irq[ IRQ_COUNTER1 ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
 159 }
 160 /*-----------------------------------------------------------*/
 161
 162 void interrupt_handler( portIRQ_TRAP_YIELD )
 163 {
 164         /* Save remaining registers. */
 165         portSAVE_CONTEXT();
 166
 167         vTaskSwitchContext();
 168
 169         /* Restore the first lot of registers, the remains will be restored when
 170         this function exits. */
 171         portRESTORE_CONTEXT();
 172 }
 173 /*-----------------------------------------------------------*/
 174
 175 /* Timer tick interrupt handler */
 176 void interrupt_handler( IRQ_COUNTER1 )
 177 {
 178         portSAVE_CONTEXT();
 179
 180         vTaskIncrementTick();
 181
 182         #if configUSE_PREEMPTION == 1
 183                 vTaskSwitchContext();
 184         #endif
 185
 186         /* Clear the Tick Interrupt. */
 187         counter1->expired = 0;
 188
 189         portRESTORE_CONTEXT();
 190 }
 191 /*-----------------------------------------------------------*/
 192
 193 void vPortEndScheduler( void )
 194 {
 195         /* Nothing to do. Unlikely to want to end. */
 196 }
 197 /*-----------------------------------------------------------*/