2 FreeRTOS V7.4.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not itcan be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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75 /*-----------------------------------------------------------
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76 * Implementation of functions defined in portable.h for the NIOS2 port.
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77 *----------------------------------------------------------*/
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79 /* Standard Includes. */
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83 /* Altera includes. */
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84 #include "sys/alt_irq.h"
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85 #include "altera_avalon_timer_regs.h"
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86 #include "priv/alt_irq_table.h"
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88 /* Scheduler includes. */
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89 #include "FreeRTOS.h"
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92 /* Interrupts are enabled. */
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93 #define portINITIAL_ESTATUS ( portSTACK_TYPE ) 0x01
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95 /*-----------------------------------------------------------*/
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98 * Setup the timer to generate the tick interrupts.
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100 static void prvSetupTimerInterrupt( void );
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103 * Call back for the alarm function.
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105 void vPortSysTickHandler( void * context, alt_u32 id );
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107 /*-----------------------------------------------------------*/
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109 static void prvReadGp( unsigned long *ulValue )
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111 asm( "stw gp, (%0)" :: "r"(ulValue) );
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113 /*-----------------------------------------------------------*/
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116 * See header file for description.
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118 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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120 portSTACK_TYPE *pxFramePointer = pxTopOfStack - 1;
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121 portSTACK_TYPE xGlobalPointer;
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123 prvReadGp( &xGlobalPointer );
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125 /* End of stack marker. */
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126 *pxTopOfStack = 0xdeadbeef;
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129 *pxTopOfStack = ( portSTACK_TYPE ) pxFramePointer;
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132 *pxTopOfStack = xGlobalPointer;
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134 /* Space for R23 to R16. */
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137 *pxTopOfStack = ( portSTACK_TYPE ) pxCode;
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140 *pxTopOfStack = portINITIAL_ESTATUS;
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142 /* Space for R15 to R5. */
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143 pxTopOfStack -= 12;
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145 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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147 /* Space for R3 to R1, muldiv and RA. */
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150 return pxTopOfStack;
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152 /*-----------------------------------------------------------*/
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155 * See header file for description.
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157 portBASE_TYPE xPortStartScheduler( void )
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159 /* Start the timer that generates the tick ISR. Interrupts are disabled
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161 prvSetupTimerInterrupt();
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163 /* Start the first task. */
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164 asm volatile ( " movia r2, restore_sp_from_pxCurrentTCB \n"
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167 /* Should not get here! */
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170 /*-----------------------------------------------------------*/
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172 void vPortEndScheduler( void )
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174 /* It is unlikely that the NIOS2 port will require this function as there
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175 is nothing to return to. */
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177 /*-----------------------------------------------------------*/
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180 * Setup the systick timer to generate the tick interrupts at the required
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183 void prvSetupTimerInterrupt( void )
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185 /* Try to register the interrupt handler. */
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186 if ( -EINVAL == alt_irq_register( SYS_CLK_IRQ, 0x0, vPortSysTickHandler ) )
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188 /* Failed to install the Interrupt Handler. */
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193 /* Configure SysTick to interrupt at the requested rate. */
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194 IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_STOP_MSK );
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195 IOWR_ALTERA_AVALON_TIMER_PERIODL( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) & 0xFFFF );
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196 IOWR_ALTERA_AVALON_TIMER_PERIODH( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) >> 16 );
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197 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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200 /* Clear any already pending interrupts generated by the Timer. */
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201 IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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203 /*-----------------------------------------------------------*/
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205 void vPortSysTickHandler( void * context, alt_u32 id )
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207 /* Increment the Kernel Tick. */
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208 vTaskIncrementTick();
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210 /* If using preemption, also force a context switch. */
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211 #if configUSE_PREEMPTION == 1
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212 vTaskSwitchContext();
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215 /* Clear the interrupt. */
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216 IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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218 /*-----------------------------------------------------------*/
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220 /** This function is a re-implementation of the Altera provided function.
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221 * The function is re-implemented to prevent it from enabling an interrupt
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222 * when it is registered. Interrupts should only be enabled after the FreeRTOS.org
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223 * kernel has its scheduler started so that contexts are saved and switched
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226 int alt_irq_register( alt_u32 id, void* context, void (*handler)(void*, alt_u32) )
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229 alt_irq_context status;
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234 * interrupts are disabled while the handler tables are updated to ensure
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235 * that an interrupt doesn't occur while the tables are in an inconsistent
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239 status = alt_irq_disable_all ();
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241 alt_irq[id].handler = handler;
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242 alt_irq[id].context = context;
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244 rc = (handler) ? alt_irq_enable (id): alt_irq_disable (id);
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246 /* alt_irq_enable_all(status); This line is removed to prevent the interrupt from being immediately enabled. */
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251 /*-----------------------------------------------------------*/
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