2 FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS is free software; you can redistribute it and/or modify it under
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7 the terms of the GNU General Public License (version 2) as published by the
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8 Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS without being obliged to provide the
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11 source code for proprietary components outside of the FreeRTOS kernel.
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12 Alternative commercial license and support terms are also available upon
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13 request. See the licensing section of http://www.FreeRTOS.org for full
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16 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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21 You should have received a copy of the GNU General Public License along
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22 with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
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23 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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26 ***************************************************************************
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28 * Looking for a quick start? Then check out the FreeRTOS eBook! *
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29 * See http://www.FreeRTOS.org/Documentation for details *
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31 ***************************************************************************
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35 Please ensure to read the configuration and relevant port sections of the
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36 online documentation.
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38 http://www.FreeRTOS.org - Documentation, latest information, license and
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41 http://www.SafeRTOS.com - A version that is certified for use in safety
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44 http://www.OpenRTOS.com - Commercial support, development, porting,
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45 licensing and training services.
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48 /*-----------------------------------------------------------
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49 * Implementation of functions defined in portable.h for the ST STR71x ARM7
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51 *----------------------------------------------------------*/
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53 /* Library includes. */
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57 /* Standard includes. */
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60 /* Scheduler includes. */
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61 #include "FreeRTOS.h"
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64 /* Constants required to setup the initial stack. */
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65 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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66 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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68 /* Constants required to handle critical sections. */
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69 #define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
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71 #define portMICROS_PER_SECOND 1000000
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73 /*-----------------------------------------------------------*/
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75 /* Setup the watchdog to generate the tick interrupts. */
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76 static void prvSetupTimerInterrupt( void );
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78 /* ulCriticalNesting will get set to zero when the first task starts. It
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79 cannot be initialised to 0 as this will cause interrupts to be enabled
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80 during the kernel initialisation process. */
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81 unsigned portLONG ulCriticalNesting = ( unsigned portLONG ) 9999;
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83 /* Tick interrupt routines for cooperative and preemptive operation
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84 respectively. The preemptive version is not defined as __irq as it is called
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85 from an asm wrapper function. */
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86 __arm __irq void vPortNonPreemptiveTick( void );
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87 void vPortPreemptiveTick( void );
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89 /*-----------------------------------------------------------*/
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92 * Initialise the stack of a task to look exactly as if a call to
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93 * portSAVE_CONTEXT had been called.
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95 * See header file for description.
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97 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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99 portSTACK_TYPE *pxOriginalTOS;
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101 pxOriginalTOS = pxTopOfStack;
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103 /* Setup the initial stack of the task. The stack is set exactly as
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104 expected by the portRESTORE_CONTEXT() macro. */
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106 /* First on the stack is the return address - which in this case is the
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107 start of the task. The offset is added to make the return address appear
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108 as it would within an IRQ ISR. */
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109 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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112 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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114 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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116 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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118 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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120 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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122 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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124 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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126 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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128 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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130 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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132 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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134 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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136 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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138 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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141 /* When the task starts is will expect to find the function parameter in
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143 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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146 /* The status register is set for system mode, with interrupts enabled. */
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147 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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150 /* Interrupt flags cannot always be stored on the stack and will
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151 instead be stored in a variable, which is then saved as part of the
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153 *pxTopOfStack = portNO_CRITICAL_NESTING;
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155 return pxTopOfStack;
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157 /*-----------------------------------------------------------*/
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159 portBASE_TYPE xPortStartScheduler( void )
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161 extern void vPortStartFirstTask( void );
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163 /* Start the timer that generates the tick ISR. Interrupts are disabled
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165 prvSetupTimerInterrupt();
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167 /* Start the first task. */
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168 vPortStartFirstTask();
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170 /* Should not get here! */
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173 /*-----------------------------------------------------------*/
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175 void vPortEndScheduler( void )
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177 /* It is unlikely that the ARM port will require this function as there
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178 is nothing to return to. */
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180 /*-----------------------------------------------------------*/
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182 /* The cooperative scheduler requires a normal IRQ service routine to
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183 simply increment the system tick. */
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184 __arm __irq void vPortNonPreemptiveTick( void )
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186 /* Increment the tick count - which may wake some tasks but as the
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187 preemptive scheduler is not being used any woken task is not given
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188 processor time no matter what its priority. */
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189 vTaskIncrementTick();
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191 /* Clear the interrupt in the watchdog and EIC. */
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195 /*-----------------------------------------------------------*/
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197 /* This function is called from an asm wrapper, so does not require the __irq
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199 void vPortPreemptiveTick( void )
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201 /* Increment the tick counter. */
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202 vTaskIncrementTick();
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204 /* The new tick value might unblock a task. Ensure the highest task that
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205 is ready to execute is the task that will execute when the tick ISR
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207 vTaskSwitchContext();
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209 /* Clear the interrupt in the watchdog and EIC. */
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213 /*-----------------------------------------------------------*/
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215 static void prvSetupTimerInterrupt( void )
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217 /* Set the watchdog up to generate a periodic tick. */
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218 WDG_ECITConfig( DISABLE );
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219 WDG_CntOnOffConfig( DISABLE );
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220 WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ );
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222 /* Setup the tick interrupt in the EIC. */
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223 EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 );
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224 EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE );
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225 EIC_IRQConfig( ENABLE );
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226 WDG_ECITConfig( ENABLE );
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228 /* Start the timer - interrupts are actually disabled at this point so
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229 it is safe to do this here. */
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230 WDG_CntOnOffConfig( ENABLE );
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232 /*-----------------------------------------------------------*/
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234 __arm __interwork void vPortEnterCritical( void )
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236 /* Disable interrupts first! */
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237 __disable_interrupt();
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239 /* Now interrupts are disabled ulCriticalNesting can be accessed
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240 directly. Increment ulCriticalNesting to keep a count of how many times
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241 portENTER_CRITICAL() has been called. */
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242 ulCriticalNesting++;
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244 /*-----------------------------------------------------------*/
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246 __arm __interwork void vPortExitCritical( void )
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248 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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250 /* Decrement the nesting count as we are leaving a critical section. */
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251 ulCriticalNesting--;
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253 /* If the nesting level has reached zero then interrupts should be
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255 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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257 __enable_interrupt();
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261 /*-----------------------------------------------------------*/
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