2 * FreeRTOS Kernel V10.0.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software. If you wish to use our Amazon
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14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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23 * http://www.FreeRTOS.org
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24 * http://aws.amazon.com/freertos
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26 * 1 tab == 4 spaces!
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29 /*-----------------------------------------------------------
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30 * Implementation of functions defined in portable.h for the ST STR71x ARM7
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32 *----------------------------------------------------------*/
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34 /* Library includes. */
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38 /* Standard includes. */
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41 /* Scheduler includes. */
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42 #include "FreeRTOS.h"
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45 /* Constants required to setup the initial stack. */
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46 #define portINITIAL_SPSR ( ( StackType_t ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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47 #define portTHUMB_MODE_BIT ( ( StackType_t ) 0x20 )
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48 #define portINSTRUCTION_SIZE ( ( StackType_t ) 4 )
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50 /* Constants required to handle critical sections. */
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51 #define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
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53 #define portMICROS_PER_SECOND 1000000
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55 /*-----------------------------------------------------------*/
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57 /* Setup the watchdog to generate the tick interrupts. */
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58 static void prvSetupTimerInterrupt( void );
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60 /* ulCriticalNesting will get set to zero when the first task starts. It
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61 cannot be initialised to 0 as this will cause interrupts to be enabled
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62 during the kernel initialisation process. */
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63 uint32_t ulCriticalNesting = ( uint32_t ) 9999;
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65 /* Tick interrupt routines for cooperative and preemptive operation
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66 respectively. The preemptive version is not defined as __irq as it is called
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67 from an asm wrapper function. */
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68 __arm __irq void vPortNonPreemptiveTick( void );
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69 void vPortPreemptiveTick( void );
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71 /*-----------------------------------------------------------*/
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74 * Initialise the stack of a task to look exactly as if a call to
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75 * portSAVE_CONTEXT had been called.
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77 * See header file for description.
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79 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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81 StackType_t *pxOriginalTOS;
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83 pxOriginalTOS = pxTopOfStack;
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85 /* To ensure asserts in tasks.c don't fail, although in this case the assert
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86 is not really required. */
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89 /* Setup the initial stack of the task. The stack is set exactly as
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90 expected by the portRESTORE_CONTEXT() macro. */
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92 /* First on the stack is the return address - which in this case is the
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93 start of the task. The offset is added to make the return address appear
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94 as it would within an IRQ ISR. */
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95 *pxTopOfStack = ( StackType_t ) pxCode + portINSTRUCTION_SIZE;
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98 *pxTopOfStack = ( StackType_t ) 0xaaaaaaaa; /* R14 */
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100 *pxTopOfStack = ( StackType_t ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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102 *pxTopOfStack = ( StackType_t ) 0x12121212; /* R12 */
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104 *pxTopOfStack = ( StackType_t ) 0x11111111; /* R11 */
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106 *pxTopOfStack = ( StackType_t ) 0x10101010; /* R10 */
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108 *pxTopOfStack = ( StackType_t ) 0x09090909; /* R9 */
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110 *pxTopOfStack = ( StackType_t ) 0x08080808; /* R8 */
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112 *pxTopOfStack = ( StackType_t ) 0x07070707; /* R7 */
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114 *pxTopOfStack = ( StackType_t ) 0x06060606; /* R6 */
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116 *pxTopOfStack = ( StackType_t ) 0x05050505; /* R5 */
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118 *pxTopOfStack = ( StackType_t ) 0x04040404; /* R4 */
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120 *pxTopOfStack = ( StackType_t ) 0x03030303; /* R3 */
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122 *pxTopOfStack = ( StackType_t ) 0x02020202; /* R2 */
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124 *pxTopOfStack = ( StackType_t ) 0x01010101; /* R1 */
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127 /* When the task starts is will expect to find the function parameter in
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129 *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
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132 /* The status register is set for system mode, with interrupts enabled. */
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133 *pxTopOfStack = ( StackType_t ) portINITIAL_SPSR;
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135 if( ( ( uint32_t ) pxCode & 0x01UL ) != 0x00UL )
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137 /* We want the task to start in thumb mode. */
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138 *pxTopOfStack |= portTHUMB_MODE_BIT;
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143 /* Interrupt flags cannot always be stored on the stack and will
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144 instead be stored in a variable, which is then saved as part of the
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146 *pxTopOfStack = portNO_CRITICAL_NESTING;
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148 return pxTopOfStack;
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150 /*-----------------------------------------------------------*/
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152 BaseType_t xPortStartScheduler( void )
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154 extern void vPortStartFirstTask( void );
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156 /* Start the timer that generates the tick ISR. Interrupts are disabled
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158 prvSetupTimerInterrupt();
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160 /* Start the first task. */
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161 vPortStartFirstTask();
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163 /* Should not get here! */
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166 /*-----------------------------------------------------------*/
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168 void vPortEndScheduler( void )
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170 /* It is unlikely that the ARM port will require this function as there
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171 is nothing to return to. */
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173 /*-----------------------------------------------------------*/
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175 /* The cooperative scheduler requires a normal IRQ service routine to
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176 simply increment the system tick. */
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177 __arm __irq void vPortNonPreemptiveTick( void )
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179 /* Increment the tick count - which may wake some tasks but as the
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180 preemptive scheduler is not being used any woken task is not given
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181 processor time no matter what its priority. */
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182 xTaskIncrementTick();
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184 /* Clear the interrupt in the watchdog and EIC. */
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188 /*-----------------------------------------------------------*/
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190 /* This function is called from an asm wrapper, so does not require the __irq
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192 void vPortPreemptiveTick( void )
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194 /* Increment the tick counter. */
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195 if( xTaskIncrementTick() != pdFALSE )
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197 /* Select a new task to execute. */
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198 vTaskSwitchContext();
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201 /* Clear the interrupt in the watchdog and EIC. */
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205 /*-----------------------------------------------------------*/
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207 static void prvSetupTimerInterrupt( void )
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209 /* Set the watchdog up to generate a periodic tick. */
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210 WDG_ECITConfig( DISABLE );
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211 WDG_CntOnOffConfig( DISABLE );
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212 WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ );
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214 /* Setup the tick interrupt in the EIC. */
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215 EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 );
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216 EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE );
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217 EIC_IRQConfig( ENABLE );
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218 WDG_ECITConfig( ENABLE );
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220 /* Start the timer - interrupts are actually disabled at this point so
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221 it is safe to do this here. */
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222 WDG_CntOnOffConfig( ENABLE );
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224 /*-----------------------------------------------------------*/
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226 __arm __interwork void vPortEnterCritical( void )
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228 /* Disable interrupts first! */
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229 __disable_interrupt();
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231 /* Now interrupts are disabled ulCriticalNesting can be accessed
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232 directly. Increment ulCriticalNesting to keep a count of how many times
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233 portENTER_CRITICAL() has been called. */
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234 ulCriticalNesting++;
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236 /*-----------------------------------------------------------*/
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238 __arm __interwork void vPortExitCritical( void )
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240 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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242 /* Decrement the nesting count as we are leaving a critical section. */
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243 ulCriticalNesting--;
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245 /* If the nesting level has reached zero then interrupts should be
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247 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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249 __enable_interrupt();
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253 /*-----------------------------------------------------------*/
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