2 FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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67 /*-----------------------------------------------------------
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68 * Implementation of functions defined in portable.h for the NIOS2 port.
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69 *----------------------------------------------------------*/
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71 /* Standard Includes. */
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75 /* Altera includes. */
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76 #include "sys/alt_irq.h"
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77 #include "altera_avalon_timer_regs.h"
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78 #include "priv/alt_irq_table.h"
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80 /* Scheduler includes. */
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81 #include "FreeRTOS.h"
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84 /* Interrupts are enabled. */
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85 #define portINITIAL_ESTATUS ( portSTACK_TYPE ) 0x01
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87 /*-----------------------------------------------------------*/
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90 * Setup the timer to generate the tick interrupts.
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92 static void prvSetupTimerInterrupt( void );
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95 * Call back for the alarm function.
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97 void vPortSysTickHandler( void * context, alt_u32 id );
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99 /*-----------------------------------------------------------*/
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101 void prvReadGp( unsigned long *ulValue )
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103 asm( "stw gp, (r4) " );
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105 /*-----------------------------------------------------------*/
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108 * See header file for description.
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110 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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112 portSTACK_TYPE *pxFramePointer = pxTopOfStack - 1;
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113 portSTACK_TYPE xGlobalPointer;
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115 prvReadGp( &xGlobalPointer );
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117 /* End of stack marker. */
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118 *pxTopOfStack = 0xdeadbeef;
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121 *pxTopOfStack = ( portSTACK_TYPE ) pxFramePointer;
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124 *pxTopOfStack = xGlobalPointer;
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126 /* Space for R23 to R16. */
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129 *pxTopOfStack = ( portSTACK_TYPE ) pxCode;
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132 *pxTopOfStack = portINITIAL_ESTATUS;
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134 /* Space for R15 to R5. */
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135 pxTopOfStack -= 12;
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137 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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139 /* Space for R3 to R1, muldiv and RA. */
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142 return pxTopOfStack;
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144 /*-----------------------------------------------------------*/
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147 * See header file for description.
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149 portBASE_TYPE xPortStartScheduler( void )
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151 /* Start the timer that generates the tick ISR. Interrupts are disabled
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153 prvSetupTimerInterrupt();
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155 /* Start the first task. */
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156 asm volatile ( " movia r2, restore_sp_from_pxCurrentTCB \n"
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159 /* Should not get here! */
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162 /*-----------------------------------------------------------*/
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164 void vPortEndScheduler( void )
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166 /* It is unlikely that the NIOS2 port will require this function as there
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167 is nothing to return to. */
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169 /*-----------------------------------------------------------*/
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172 * Setup the systick timer to generate the tick interrupts at the required
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175 void prvSetupTimerInterrupt( void )
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177 /* Try to register the interrupt handler. */
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178 if ( -EINVAL == alt_irq_register( SYS_CLK_IRQ, 0x0, vPortSysTickHandler ) )
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180 /* Failed to install the Interrupt Handler. */
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185 /* Configure SysTick to interrupt at the requested rate. */
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186 IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_STOP_MSK );
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187 IOWR_ALTERA_AVALON_TIMER_PERIODL( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) & 0xFFFF );
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188 IOWR_ALTERA_AVALON_TIMER_PERIODH( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) >> 16 );
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189 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 );
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192 /* Clear any already pending interrupts generated by the Timer. */
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193 IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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195 /*-----------------------------------------------------------*/
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197 void vPortSysTickHandler( void * context, alt_u32 id )
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199 /* Increment the Kernel Tick. */
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200 vTaskIncrementTick();
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202 /* If using preemption, also force a context switch. */
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203 #if configUSE_PREEMPTION == 1
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204 vTaskSwitchContext();
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207 /* Clear the interrupt. */
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208 IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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210 /*-----------------------------------------------------------*/
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212 /** This function is a re-implementation of the Altera provided function.
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213 * The function is re-implemented to prevent it from enabling an interrupt
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214 * when it is registered. Interrupts should only be enabled after the FreeRTOS.org
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215 * kernel has its scheduler started so that contexts are saved and switched
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218 int alt_irq_register( alt_u32 id, void* context, void (*handler)(void*, alt_u32) )
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221 alt_irq_context status;
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226 * interrupts are disabled while the handler tables are updated to ensure
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227 * that an interrupt doesn't occur while the tables are in an inconsistent
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231 status = alt_irq_disable_all ();
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233 alt_irq[id].handler = handler;
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234 alt_irq[id].context = context;
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236 rc = (handler) ? alt_irq_enable (id): alt_irq_disable (id);
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238 /* alt_irq_enable_all(status); This line is removed to prevent the interrupt from being immediately enabled. */
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243 /*-----------------------------------------------------------*/
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