2 FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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52 /*-----------------------------------------------------------
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53 * Implementation of functions defined in portable.h for the ST STR71x ARM7
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55 *----------------------------------------------------------*/
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57 /* Library includes. */
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61 /* Standard includes. */
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64 /* Scheduler includes. */
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65 #include "FreeRTOS.h"
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68 /* Constants required to setup the initial stack. */
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69 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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70 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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72 /* Constants required to handle critical sections. */
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73 #define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
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75 #define portMICROS_PER_SECOND 1000000
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77 /*-----------------------------------------------------------*/
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79 /* Setup the watchdog to generate the tick interrupts. */
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80 static void prvSetupTimerInterrupt( void );
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82 /* ulCriticalNesting will get set to zero when the first task starts. It
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83 cannot be initialised to 0 as this will cause interrupts to be enabled
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84 during the kernel initialisation process. */
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85 unsigned portLONG ulCriticalNesting = ( unsigned portLONG ) 9999;
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87 /* Tick interrupt routines for cooperative and preemptive operation
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88 respectively. The preemptive version is not defined as __irq as it is called
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89 from an asm wrapper function. */
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90 __arm __irq void vPortNonPreemptiveTick( void );
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91 void vPortPreemptiveTick( void );
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93 /*-----------------------------------------------------------*/
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96 * Initialise the stack of a task to look exactly as if a call to
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97 * portSAVE_CONTEXT had been called.
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99 * See header file for description.
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101 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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103 portSTACK_TYPE *pxOriginalTOS;
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105 pxOriginalTOS = pxTopOfStack;
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107 /* Setup the initial stack of the task. The stack is set exactly as
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108 expected by the portRESTORE_CONTEXT() macro. */
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110 /* First on the stack is the return address - which in this case is the
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111 start of the task. The offset is added to make the return address appear
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112 as it would within an IRQ ISR. */
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113 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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116 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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118 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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120 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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122 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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124 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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126 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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128 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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130 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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132 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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134 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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136 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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138 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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140 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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142 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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145 /* When the task starts is will expect to find the function parameter in
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147 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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150 /* The status register is set for system mode, with interrupts enabled. */
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151 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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154 /* Interrupt flags cannot always be stored on the stack and will
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155 instead be stored in a variable, which is then saved as part of the
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157 *pxTopOfStack = portNO_CRITICAL_NESTING;
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159 return pxTopOfStack;
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161 /*-----------------------------------------------------------*/
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163 portBASE_TYPE xPortStartScheduler( void )
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165 extern void vPortStartFirstTask( void );
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167 /* Start the timer that generates the tick ISR. Interrupts are disabled
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169 prvSetupTimerInterrupt();
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171 /* Start the first task. */
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172 vPortStartFirstTask();
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174 /* Should not get here! */
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177 /*-----------------------------------------------------------*/
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179 void vPortEndScheduler( void )
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181 /* It is unlikely that the ARM port will require this function as there
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182 is nothing to return to. */
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184 /*-----------------------------------------------------------*/
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186 /* The cooperative scheduler requires a normal IRQ service routine to
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187 simply increment the system tick. */
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188 __arm __irq void vPortNonPreemptiveTick( void )
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190 /* Increment the tick count - which may wake some tasks but as the
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191 preemptive scheduler is not being used any woken task is not given
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192 processor time no matter what its priority. */
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193 vTaskIncrementTick();
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195 /* Clear the interrupt in the watchdog and EIC. */
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199 /*-----------------------------------------------------------*/
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201 /* This function is called from an asm wrapper, so does not require the __irq
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203 void vPortPreemptiveTick( void )
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205 /* Increment the tick counter. */
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206 vTaskIncrementTick();
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208 /* The new tick value might unblock a task. Ensure the highest task that
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209 is ready to execute is the task that will execute when the tick ISR
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211 vTaskSwitchContext();
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213 /* Clear the interrupt in the watchdog and EIC. */
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217 /*-----------------------------------------------------------*/
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219 static void prvSetupTimerInterrupt( void )
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221 /* Set the watchdog up to generate a periodic tick. */
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222 WDG_ECITConfig( DISABLE );
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223 WDG_CntOnOffConfig( DISABLE );
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224 WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ );
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226 /* Setup the tick interrupt in the EIC. */
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227 EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 );
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228 EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE );
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229 EIC_IRQConfig( ENABLE );
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230 WDG_ECITConfig( ENABLE );
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232 /* Start the timer - interrupts are actually disabled at this point so
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233 it is safe to do this here. */
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234 WDG_CntOnOffConfig( ENABLE );
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236 /*-----------------------------------------------------------*/
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238 __arm __interwork void vPortEnterCritical( void )
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240 /* Disable interrupts first! */
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241 __disable_interrupt();
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243 /* Now interrupts are disabled ulCriticalNesting can be accessed
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244 directly. Increment ulCriticalNesting to keep a count of how many times
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245 portENTER_CRITICAL() has been called. */
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246 ulCriticalNesting++;
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248 /*-----------------------------------------------------------*/
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250 __arm __interwork void vPortExitCritical( void )
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252 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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254 /* Decrement the nesting count as we are leaving a critical section. */
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255 ulCriticalNesting--;
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257 /* If the nesting level has reached zero then interrupts should be
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259 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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261 __enable_interrupt();
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265 /*-----------------------------------------------------------*/
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