2 FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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70 /*-----------------------------------------------------------
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71 * Implementation of functions defined in portable.h for the ST STR75x ARM7
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73 *----------------------------------------------------------*/
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75 /* Library includes. */
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77 #include "75x_eic.h"
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79 /* Scheduler includes. */
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80 #include "FreeRTOS.h"
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83 /* Constants required to setup the initial stack. */
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84 #define portINITIAL_SPSR ( ( StackType_t ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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85 #define portINSTRUCTION_SIZE ( ( StackType_t ) 4 )
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87 /* Constants required to handle critical sections. */
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88 #define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
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90 /* Prescale used on the timer clock when calculating the tick period. */
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91 #define portPRESCALE 20
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94 /*-----------------------------------------------------------*/
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96 /* Setup the TB to generate the tick interrupts. */
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97 static void prvSetupTimerInterrupt( void );
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99 /* ulCriticalNesting will get set to zero when the first task starts. It
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100 cannot be initialised to 0 as this will cause interrupts to be enabled
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101 during the kernel initialisation process. */
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102 uint32_t ulCriticalNesting = ( uint32_t ) 9999;
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104 /* Tick interrupt routines for preemptive operation. */
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105 __arm void vPortPreemptiveTick( void );
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107 /*-----------------------------------------------------------*/
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110 * Initialise the stack of a task to look exactly as if a call to
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111 * portSAVE_CONTEXT had been called.
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113 * See header file for description.
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115 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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117 StackType_t *pxOriginalTOS;
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119 pxOriginalTOS = pxTopOfStack;
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121 /* To ensure asserts in tasks.c don't fail, although in this case the assert
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122 is not really required. */
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125 /* Setup the initial stack of the task. The stack is set exactly as
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126 expected by the portRESTORE_CONTEXT() macro. */
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128 /* First on the stack is the return address - which in this case is the
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129 start of the task. The offset is added to make the return address appear
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130 as it would within an IRQ ISR. */
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131 *pxTopOfStack = ( StackType_t ) pxCode + portINSTRUCTION_SIZE;
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134 *pxTopOfStack = ( StackType_t ) 0xaaaaaaaa; /* R14 */
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136 *pxTopOfStack = ( StackType_t ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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138 *pxTopOfStack = ( StackType_t ) 0x12121212; /* R12 */
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140 *pxTopOfStack = ( StackType_t ) 0x11111111; /* R11 */
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142 *pxTopOfStack = ( StackType_t ) 0x10101010; /* R10 */
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144 *pxTopOfStack = ( StackType_t ) 0x09090909; /* R9 */
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146 *pxTopOfStack = ( StackType_t ) 0x08080808; /* R8 */
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148 *pxTopOfStack = ( StackType_t ) 0x07070707; /* R7 */
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150 *pxTopOfStack = ( StackType_t ) 0x06060606; /* R6 */
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152 *pxTopOfStack = ( StackType_t ) 0x05050505; /* R5 */
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154 *pxTopOfStack = ( StackType_t ) 0x04040404; /* R4 */
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156 *pxTopOfStack = ( StackType_t ) 0x03030303; /* R3 */
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158 *pxTopOfStack = ( StackType_t ) 0x02020202; /* R2 */
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160 *pxTopOfStack = ( StackType_t ) 0x01010101; /* R1 */
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163 /* When the task starts is will expect to find the function parameter in
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165 *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
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168 /* The status register is set for system mode, with interrupts enabled. */
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169 *pxTopOfStack = ( StackType_t ) portINITIAL_SPSR;
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172 /* Interrupt flags cannot always be stored on the stack and will
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173 instead be stored in a variable, which is then saved as part of the
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175 *pxTopOfStack = portNO_CRITICAL_NESTING;
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177 return pxTopOfStack;
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179 /*-----------------------------------------------------------*/
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181 BaseType_t xPortStartScheduler( void )
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183 extern void vPortStartFirstTask( void );
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185 /* Start the timer that generates the tick ISR. Interrupts are disabled
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187 prvSetupTimerInterrupt();
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189 /* Start the first task. */
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190 vPortStartFirstTask();
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192 /* Should not get here! */
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195 /*-----------------------------------------------------------*/
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197 void vPortEndScheduler( void )
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199 /* It is unlikely that the ARM port will require this function as there
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200 is nothing to return to. */
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202 /*-----------------------------------------------------------*/
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204 __arm void vPortPreemptiveTick( void )
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206 /* Increment the tick counter. */
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207 if( xTaskIncrementTick() != pdFALSE )
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209 /* Select a new task to execute. */
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210 vTaskSwitchContext();
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213 TB_ClearITPendingBit( TB_IT_Update );
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215 /*-----------------------------------------------------------*/
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217 static void prvSetupTimerInterrupt( void )
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219 EIC_IRQInitTypeDef EIC_IRQInitStructure;
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220 TB_InitTypeDef TB_InitStructure;
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222 /* Setup the EIC for the TB. */
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223 EIC_IRQInitStructure.EIC_IRQChannelCmd = ENABLE;
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224 EIC_IRQInitStructure.EIC_IRQChannel = TB_IRQChannel;
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225 EIC_IRQInitStructure.EIC_IRQChannelPriority = 1;
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226 EIC_IRQInit(&EIC_IRQInitStructure);
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228 /* Setup the TB for the generation of the tick interrupt. */
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229 TB_InitStructure.TB_Mode = TB_Mode_Timing;
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230 TB_InitStructure.TB_CounterMode = TB_CounterMode_Down;
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231 TB_InitStructure.TB_Prescaler = portPRESCALE - 1;
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232 TB_InitStructure.TB_AutoReload = ( ( configCPU_CLOCK_HZ / portPRESCALE ) / configTICK_RATE_HZ );
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233 TB_Init(&TB_InitStructure);
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235 /* Enable TB Update interrupt */
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236 TB_ITConfig(TB_IT_Update, ENABLE);
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238 /* Clear TB Update interrupt pending bit */
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239 TB_ClearITPendingBit(TB_IT_Update);
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244 /*-----------------------------------------------------------*/
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246 __arm __interwork void vPortEnterCritical( void )
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248 /* Disable interrupts first! */
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249 __disable_interrupt();
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251 /* Now interrupts are disabled ulCriticalNesting can be accessed
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252 directly. Increment ulCriticalNesting to keep a count of how many times
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253 portENTER_CRITICAL() has been called. */
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254 ulCriticalNesting++;
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256 /*-----------------------------------------------------------*/
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258 __arm __interwork void vPortExitCritical( void )
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260 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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262 /* Decrement the nesting count as we are leaving a critical section. */
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263 ulCriticalNesting--;
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265 /* If the nesting level has reached zero then interrupts should be
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267 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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269 __enable_interrupt();
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273 /*-----------------------------------------------------------*/
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