2 FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd.
\r
5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
\r
7 ***************************************************************************
\r
9 * FreeRTOS provides completely free yet professionally developed, *
\r
10 * robust, strictly quality controlled, supported, and cross *
\r
11 * platform software that has become a de facto standard. *
\r
13 * Help yourself get started quickly and support the FreeRTOS *
\r
14 * project by purchasing a FreeRTOS tutorial book, reference *
\r
15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
\r
19 ***************************************************************************
\r
21 This file is part of the FreeRTOS distribution.
\r
23 FreeRTOS is free software; you can redistribute it and/or modify it under
\r
24 the terms of the GNU General Public License (version 2) as published by the
\r
25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
\r
27 >>! NOTE: The modification to the GPL is included to allow you to !<<
\r
28 >>! distribute a combined work that includes FreeRTOS without being !<<
\r
29 >>! obliged to provide the source code for proprietary components !<<
\r
30 >>! outside of the FreeRTOS kernel. !<<
\r
32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
\r
33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
\r
34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
\r
35 link: http://www.freertos.org/a00114.html
\r
39 ***************************************************************************
\r
41 * Having a problem? Start by reading the FAQ "My application does *
\r
42 * not run, what could be wrong?" *
\r
44 * http://www.FreeRTOS.org/FAQHelp.html *
\r
46 ***************************************************************************
\r
48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
\r
49 license and Real Time Engineers Ltd. contact details.
\r
51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
\r
52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
\r
53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
\r
55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
\r
56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
\r
57 licenses offer ticketed support, indemnification and middleware.
\r
59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
\r
60 engineered and independently SIL3 certified version for use in safety and
\r
61 mission critical applications that require provable dependability.
\r
66 /* Standard includes. */
\r
69 /* Scheduler includes. */
\r
70 #include "FreeRTOS.h"
\r
73 #ifndef configINTERRUPT_CONTROLLER_BASE_ADDRESS
\r
74 #error configINTERRUPT_CONTROLLER_BASE_ADDRESS must be defined. See http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html
\r
77 #ifndef configINTERRUPT_CONTROLLER_CPU_INTERFACE_OFFSET
\r
78 #error configINTERRUPT_CONTROLLER_CPU_INTERFACE_OFFSET must be defined. See http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html
\r
81 #ifndef configUNIQUE_INTERRUPT_PRIORITIES
\r
82 #error configUNIQUE_INTERRUPT_PRIORITIES must be defined. See http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html
\r
85 #ifndef configSETUP_TICK_INTERRUPT
\r
86 #error configSETUP_TICK_INTERRUPT() must be defined. See http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html
\r
87 #endif /* configSETUP_TICK_INTERRUPT */
\r
89 #ifndef configMAX_API_CALL_INTERRUPT_PRIORITY
\r
90 #error configMAX_API_CALL_INTERRUPT_PRIORITY must be defined. See http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html
\r
93 #if configMAX_API_CALL_INTERRUPT_PRIORITY == 0
\r
94 #error configMAX_API_CALL_INTERRUPT_PRIORITY must not be set to 0
\r
97 #if configMAX_API_CALL_INTERRUPT_PRIORITY > configUNIQUE_INTERRUPT_PRIORITIES
\r
98 #error configMAX_API_CALL_INTERRUPT_PRIORITY must be less than or equal to configUNIQUE_INTERRUPT_PRIORITIES as the lower the numeric priority value the higher the logical interrupt priority
\r
101 #if configUSE_PORT_OPTIMISED_TASK_SELECTION == 1
\r
102 /* Check the configuration. */
\r
103 #if( configMAX_PRIORITIES > 32 )
\r
104 #error configUSE_PORT_OPTIMISED_TASK_SELECTION can only be set to 1 when configMAX_PRIORITIES is less than or equal to 32. It is very rare that a system requires more than 10 to 15 difference priorities as tasks that share a priority will time slice.
\r
106 #endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */
\r
108 /* In case security extensions are implemented. */
\r
109 #if configMAX_API_CALL_INTERRUPT_PRIORITY <= ( configUNIQUE_INTERRUPT_PRIORITIES / 2 )
\r
110 #error configMAX_API_CALL_INTERRUPT_PRIORITY must be greater than ( configUNIQUE_INTERRUPT_PRIORITIES / 2 )
\r
113 /* Used to check non ISR safe API functions are not called from inside an
\r
115 #define portASSERT_IF_IN_INTERRUPT() configASSERT( ( portICCRPR_RUNNING_PRIORITY_REGISTER == 0xffUL ) || ( portICCRPR_RUNNING_PRIORITY_REGISTER == portLOWEST_INTERRUPT_PRIORITY ) )
\r
117 /* Some vendor specific files default configCLEAR_TICK_INTERRUPT() in
\r
119 #ifndef configCLEAR_TICK_INTERRUPT
\r
120 #define configCLEAR_TICK_INTERRUPT()
\r
123 /* A critical section is exited when the critical section nesting count reaches
\r
125 #define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
\r
127 /* In all GICs 255 can be written to the priority mask register to unmask all
\r
128 (but the lowest) interrupt priority. */
\r
129 #define portUNMASK_VALUE ( 0xFFUL )
\r
131 /* Tasks are not created with a floating point context, but can be given a
\r
132 floating point context after they have been created. A variable is stored as
\r
133 part of the tasks context that holds portNO_FLOATING_POINT_CONTEXT if the task
\r
134 does not have an FPU context, or any other value if the task does have an FPU
\r
136 #define portNO_FLOATING_POINT_CONTEXT ( ( StackType_t ) 0 )
\r
138 /* Constants required to setup the initial task context. */
\r
139 #define portINITIAL_SPSR ( ( StackType_t ) 0x1f ) /* System mode, ARM mode, IRQ enabled FIQ enabled. */
\r
140 #define portTHUMB_MODE_BIT ( ( StackType_t ) 0x20 )
\r
141 #define portINTERRUPT_ENABLE_BIT ( 0x80UL )
\r
142 #define portTHUMB_MODE_ADDRESS ( 0x01UL )
\r
144 /* Used by portASSERT_IF_INTERRUPT_PRIORITY_INVALID() when ensuring the binary
\r
146 #define portBINARY_POINT_BITS ( ( uint8_t ) 0x03 )
\r
148 /* Masks all bits in the APSR other than the mode bits. */
\r
149 #define portAPSR_MODE_BITS_MASK ( 0x1F )
\r
151 /* The value of the mode bits in the APSR when the CPU is executing in user
\r
153 #define portAPSR_USER_MODE ( 0x10 )
\r
155 /* The critical section macros only mask interrupts up to an application
\r
156 determined priority level. Sometimes it is necessary to turn interrupt off in
\r
157 the CPU itself before modifying certain hardware registers. */
\r
158 #define portCPU_IRQ_DISABLE() \
\r
159 __asm volatile ( "CPSID i" ); \
\r
160 __asm volatile ( "DSB" ); \
\r
161 __asm volatile ( "ISB" );
\r
163 #define portCPU_IRQ_ENABLE() \
\r
164 __asm volatile ( "CPSIE i" ); \
\r
165 __asm volatile ( "DSB" ); \
\r
166 __asm volatile ( "ISB" );
\r
169 /* Macro to unmask all interrupt priorities. */
\r
170 #define portCLEAR_INTERRUPT_MASK() \
\r
172 portCPU_IRQ_DISABLE(); \
\r
173 portICCPMR_PRIORITY_MASK_REGISTER = portUNMASK_VALUE; \
\r
176 portCPU_IRQ_ENABLE(); \
\r
179 #define portINTERRUPT_PRIORITY_REGISTER_OFFSET 0x400UL
\r
180 #define portMAX_8_BIT_VALUE ( ( uint8_t ) 0xff )
\r
181 #define portBIT_0_SET ( ( uint8_t ) 0x01 )
\r
183 /*-----------------------------------------------------------*/
\r
186 * Starts the first task executing. This function is necessarily written in
\r
187 * assembly code so is implemented in portASM.s.
\r
189 extern void vPortRestoreTaskContext( void );
\r
191 /*-----------------------------------------------------------*/
\r
193 /* A variable is used to keep track of the critical section nesting. This
\r
194 variable has to be stored as part of the task context and must be initialised to
\r
195 a non zero value to ensure interrupts don't inadvertently become unmasked before
\r
196 the scheduler starts. As it is stored as part of the task context it will
\r
197 automatically be set to 0 when the first task is started. */
\r
198 volatile uint32_t ulCriticalNesting = 9999UL;
\r
200 /* Saved as part of the task context. If ulPortTaskHasFPUContext is non-zero then
\r
201 a floating point context must be saved and restored for the task. */
\r
202 uint32_t ulPortTaskHasFPUContext = pdFALSE;
\r
204 /* Set to 1 to pend a context switch from an ISR. */
\r
205 uint32_t ulPortYieldRequired = pdFALSE;
\r
207 /* Counts the interrupt nesting depth. A context switch is only performed if
\r
208 if the nesting depth is 0. */
\r
209 uint32_t ulPortInterruptNesting = 0UL;
\r
211 __attribute__(( used )) const uint32_t ulICCIAR = portICCIAR_INTERRUPT_ACKNOWLEDGE_REGISTER_ADDRESS;
\r
212 __attribute__(( used )) const uint32_t ulICCEOIR = portICCEOIR_END_OF_INTERRUPT_REGISTER_ADDRESS;
\r
213 __attribute__(( used )) const uint32_t ulICCPMR = portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS;
\r
214 __attribute__(( used )) const uint32_t ulMaxAPIPriorityMask = ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT );
\r
216 /*-----------------------------------------------------------*/
\r
219 * See header file for description.
\r
221 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
\r
223 /* Setup the initial stack of the task. The stack is set exactly as
\r
224 expected by the portRESTORE_CONTEXT() macro.
\r
226 The fist real value on the stack is the status register, which is set for
\r
227 system mode, with interrupts enabled. A few NULLs are added first to ensure
\r
228 GDB does not try decoding a non-existent return address. */
\r
229 *pxTopOfStack = ( StackType_t ) NULL;
\r
231 *pxTopOfStack = ( StackType_t ) NULL;
\r
233 *pxTopOfStack = ( StackType_t ) NULL;
\r
235 *pxTopOfStack = ( StackType_t ) portINITIAL_SPSR;
\r
237 if( ( ( uint32_t ) pxCode & portTHUMB_MODE_ADDRESS ) != 0x00UL )
\r
239 /* The task will start in THUMB mode. */
\r
240 *pxTopOfStack |= portTHUMB_MODE_BIT;
\r
245 /* Next the return address, which in this case is the start of the task. */
\r
246 *pxTopOfStack = ( StackType_t ) pxCode;
\r
249 /* Next all the registers other than the stack pointer. */
\r
250 *pxTopOfStack = ( StackType_t ) 0x00000000; /* R14 */
\r
252 *pxTopOfStack = ( StackType_t ) 0x12121212; /* R12 */
\r
254 *pxTopOfStack = ( StackType_t ) 0x11111111; /* R11 */
\r
256 *pxTopOfStack = ( StackType_t ) 0x10101010; /* R10 */
\r
258 *pxTopOfStack = ( StackType_t ) 0x09090909; /* R9 */
\r
260 *pxTopOfStack = ( StackType_t ) 0x08080808; /* R8 */
\r
262 *pxTopOfStack = ( StackType_t ) 0x07070707; /* R7 */
\r
264 *pxTopOfStack = ( StackType_t ) 0x06060606; /* R6 */
\r
266 *pxTopOfStack = ( StackType_t ) 0x05050505; /* R5 */
\r
268 *pxTopOfStack = ( StackType_t ) 0x04040404; /* R4 */
\r
270 *pxTopOfStack = ( StackType_t ) 0x03030303; /* R3 */
\r
272 *pxTopOfStack = ( StackType_t ) 0x02020202; /* R2 */
\r
274 *pxTopOfStack = ( StackType_t ) 0x01010101; /* R1 */
\r
276 *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
\r
279 /* The task will start with a critical nesting count of 0 as interrupts are
\r
281 *pxTopOfStack = portNO_CRITICAL_NESTING;
\r
284 /* The task will start without a floating point context. A task that uses
\r
285 the floating point hardware must call vPortTaskUsesFPU() before executing
\r
286 any floating point instructions. */
\r
287 *pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
\r
289 return pxTopOfStack;
\r
291 /*-----------------------------------------------------------*/
\r
293 BaseType_t xPortStartScheduler( void )
\r
297 #if( configASSERT_DEFINED == 1 )
\r
299 volatile uint32_t ulOriginalPriority;
\r
300 volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( configINTERRUPT_CONTROLLER_BASE_ADDRESS + portINTERRUPT_PRIORITY_REGISTER_OFFSET );
\r
301 volatile uint8_t ucMaxPriorityValue;
\r
303 /* Determine how many priority bits are implemented in the GIC.
\r
305 Save the interrupt priority value that is about to be clobbered. */
\r
306 ulOriginalPriority = *pucFirstUserPriorityRegister;
\r
308 /* Determine the number of priority bits available. First write to
\r
309 all possible bits. */
\r
310 *pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE;
\r
312 /* Read the value back to see how many bits stuck. */
\r
313 ucMaxPriorityValue = *pucFirstUserPriorityRegister;
\r
315 /* Shift to the least significant bits. */
\r
316 while( ( ucMaxPriorityValue & portBIT_0_SET ) != portBIT_0_SET )
\r
318 ucMaxPriorityValue >>= ( uint8_t ) 0x01;
\r
321 /* Sanity check configUNIQUE_INTERRUPT_PRIORITIES matches the read
\r
323 configASSERT( ucMaxPriorityValue == portLOWEST_INTERRUPT_PRIORITY );
\r
325 /* Restore the clobbered interrupt priority register to its original
\r
327 *pucFirstUserPriorityRegister = ulOriginalPriority;
\r
329 #endif /* conifgASSERT_DEFINED */
\r
332 /* Only continue if the CPU is not in User mode. The CPU must be in a
\r
333 Privileged mode for the scheduler to start. */
\r
334 __asm volatile ( "MRS %0, APSR" : "=r" ( ulAPSR ) );
\r
335 ulAPSR &= portAPSR_MODE_BITS_MASK;
\r
336 configASSERT( ulAPSR != portAPSR_USER_MODE );
\r
338 if( ulAPSR != portAPSR_USER_MODE )
\r
340 /* Only continue if the binary point value is set to its lowest possible
\r
341 setting. See the comments in vPortValidateInterruptPriority() below for
\r
342 more information. */
\r
343 configASSERT( ( portICCBPR_BINARY_POINT_REGISTER & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
\r
345 if( ( portICCBPR_BINARY_POINT_REGISTER & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE )
\r
347 /* Interrupts are turned off in the CPU itself to ensure tick does
\r
348 not execute while the scheduler is being started. Interrupts are
\r
349 automatically turned back on in the CPU when the first task starts
\r
351 portCPU_IRQ_DISABLE();
\r
353 /* Start the timer that generates the tick ISR. */
\r
354 configSETUP_TICK_INTERRUPT();
\r
356 /* Start the first task executing. */
\r
357 vPortRestoreTaskContext();
\r
361 /* Will only get here if xTaskStartScheduler() was called with the CPU in
\r
362 a non-privileged mode or the binary point register was not set to its lowest
\r
366 /*-----------------------------------------------------------*/
\r
368 void vPortEndScheduler( void )
\r
370 /* Not implemented in ports where there is nothing to return to.
\r
371 Artificially force an assert. */
\r
372 configASSERT( ulCriticalNesting == 1000UL );
\r
374 /*-----------------------------------------------------------*/
\r
376 void vPortEnterCritical( void )
\r
378 /* This is not the interrupt safe version of the enter critical function.
\r
379 Only API functions that end in "FromISR" can be used in an interrupt. */
\r
380 portASSERT_IF_IN_INTERRUPT();
\r
382 /* Mask interrupts up to the max syscall interrupt priority. */
\r
383 ulPortSetInterruptMask();
\r
385 /* Now interrupts are disabled ulCriticalNesting can be accessed
\r
386 directly. Increment ulCriticalNesting to keep a count of how many times
\r
387 portENTER_CRITICAL() has been called. */
\r
388 ulCriticalNesting++;
\r
390 /*-----------------------------------------------------------*/
\r
392 void vPortExitCritical( void )
\r
394 /* This is not the interrupt safe version of the enter critical function.
\r
395 Only API functions that end in "FromISR" can be used in an interrupt. */
\r
396 portASSERT_IF_IN_INTERRUPT();
\r
398 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
\r
400 /* Decrement the nesting count as the critical section is being
\r
402 ulCriticalNesting--;
\r
404 /* If the nesting level has reached zero then all interrupt
\r
405 priorities must be re-enabled. */
\r
406 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
\r
408 /* Critical nesting has reached zero so all interrupt priorities
\r
409 should be unmasked. */
\r
410 portCLEAR_INTERRUPT_MASK();
\r
414 /*-----------------------------------------------------------*/
\r
416 void FreeRTOS_Tick_Handler( void )
\r
418 /* Set interrupt mask before altering scheduler structures. The tick
\r
419 handler runs at the lowest priority, so interrupts cannot already be masked,
\r
420 so there is no need to save and restore the current mask value. It is
\r
421 necessary to turn off interrupts in the CPU itself while the ICCPMR is being
\r
423 portCPU_IRQ_DISABLE();
\r
424 portICCPMR_PRIORITY_MASK_REGISTER = ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT );
\r
425 __asm volatile ( "dsb \n"
\r
427 portCPU_IRQ_ENABLE();
\r
429 /* Increment the RTOS tick. */
\r
430 if( xTaskIncrementTick() != pdFALSE )
\r
432 ulPortYieldRequired = pdTRUE;
\r
435 /* Ensure all interrupt priorities are active again. */
\r
436 portCLEAR_INTERRUPT_MASK();
\r
437 configCLEAR_TICK_INTERRUPT();
\r
439 /*-----------------------------------------------------------*/
\r
441 void vPortTaskUsesFPU( void )
\r
443 uint32_t ulInitialFPSCR = 0;
\r
445 /* A task is registering the fact that it needs an FPU context. Set the
\r
446 FPU flag (which is saved as part of the task context). */
\r
447 ulPortTaskHasFPUContext = pdTRUE;
\r
449 /* Initialise the floating point status register. */
\r
450 __asm volatile ( "FMXR FPSCR, %0" :: "r" (ulInitialFPSCR) );
\r
452 /*-----------------------------------------------------------*/
\r
454 void vPortClearInterruptMask( uint32_t ulNewMaskValue )
\r
456 if( ulNewMaskValue == pdFALSE )
\r
458 portCLEAR_INTERRUPT_MASK();
\r
461 /*-----------------------------------------------------------*/
\r
463 uint32_t ulPortSetInterruptMask( void )
\r
467 /* Interrupt in the CPU must be turned off while the ICCPMR is being
\r
469 portCPU_IRQ_DISABLE();
\r
470 if( portICCPMR_PRIORITY_MASK_REGISTER == ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) )
\r
472 /* Interrupts were already masked. */
\r
477 ulReturn = pdFALSE;
\r
478 portICCPMR_PRIORITY_MASK_REGISTER = ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT );
\r
479 __asm volatile ( "dsb \n"
\r
482 portCPU_IRQ_ENABLE();
\r
486 /*-----------------------------------------------------------*/
\r
488 #if( configASSERT_DEFINED == 1 )
\r
490 void vPortValidateInterruptPriority( void )
\r
492 /* The following assertion will fail if a service routine (ISR) for
\r
493 an interrupt that has been assigned a priority above
\r
494 configMAX_SYSCALL_INTERRUPT_PRIORITY calls an ISR safe FreeRTOS API
\r
495 function. ISR safe FreeRTOS API functions must *only* be called
\r
496 from interrupts that have been assigned a priority at or below
\r
497 configMAX_SYSCALL_INTERRUPT_PRIORITY.
\r
499 Numerically low interrupt priority numbers represent logically high
\r
500 interrupt priorities, therefore the priority of the interrupt must
\r
501 be set to a value equal to or numerically *higher* than
\r
502 configMAX_SYSCALL_INTERRUPT_PRIORITY.
\r
504 FreeRTOS maintains separate thread and ISR API functions to ensure
\r
505 interrupt entry is as fast and simple as possible. */
\r
507 configASSERT( portICCRPR_RUNNING_PRIORITY_REGISTER >= ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) );
\r
509 /* Priority grouping: The interrupt controller (GIC) allows the bits
\r
510 that define each interrupt's priority to be split between bits that
\r
511 define the interrupt's pre-emption priority bits and bits that define
\r
512 the interrupt's sub-priority. For simplicity all bits must be defined
\r
513 to be pre-emption priority bits. The following assertion will fail if
\r
514 this is not the case (if some bits represent a sub-priority).
\r
516 The priority grouping is configured by the GIC's binary point register
\r
517 (ICCBPR). Writting 0 to ICCBPR will ensure it is set to its lowest
\r
518 possible value (which may be above 0). */
\r
519 configASSERT( ( portICCBPR_BINARY_POINT_REGISTER & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
\r
522 #endif /* configASSERT_DEFINED */
\r
523 /*-----------------------------------------------------------*/
\r