2 * FreeRTOS Kernel V10.0.0
\r
3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
\r
5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
\r
6 * this software and associated documentation files (the "Software"), to deal in
\r
7 * the Software without restriction, including without limitation the rights to
\r
8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
\r
9 * the Software, and to permit persons to whom the Software is furnished to do so,
\r
10 * subject to the following conditions:
\r
12 * The above copyright notice and this permission notice shall be included in all
\r
13 * copies or substantial portions of the Software. If you wish to use our Amazon
\r
14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
\r
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
\r
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
\r
18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
\r
19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
\r
20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
\r
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\r
23 * http://www.FreeRTOS.org
\r
24 * http://aws.amazon.com/freertos
\r
26 * 1 tab == 4 spaces!
\r
31 #include "FreeRTOS.h"
\r
34 /*-----------------------------------------------------------
\r
35 * Implementation of functions defined in portable.h for the AVR/IAR port.
\r
36 *----------------------------------------------------------*/
\r
38 /* Start tasks with interrupts enables. */
\r
39 #define portFLAGS_INT_ENABLED ( ( StackType_t ) 0x80 )
\r
41 /* Hardware constants for timer 1. */
\r
42 #define portCLEAR_COUNTER_ON_MATCH ( ( uint8_t ) 0x08 )
\r
43 #define portPRESCALE_64 ( ( uint8_t ) 0x03 )
\r
44 #define portCLOCK_PRESCALER ( ( uint32_t ) 64 )
\r
45 #define portCOMPARE_MATCH_A_INTERRUPT_ENABLE ( ( uint8_t ) 0x10 )
\r
47 /* The number of bytes used on the hardware stack by the task start address. */
\r
48 #define portBYTES_USED_BY_RETURN_ADDRESS ( 2 )
\r
49 /*-----------------------------------------------------------*/
\r
51 /* Stores the critical section nesting. This must not be initialised to 0.
\r
52 It will be initialised when a task starts. */
\r
53 #define portNO_CRITICAL_NESTING ( ( UBaseType_t ) 0 )
\r
54 UBaseType_t uxCriticalNesting = 0x50;
\r
58 * Perform hardware setup to enable ticks from timer 1, compare match A.
\r
60 static void prvSetupTimerInterrupt( void );
\r
63 * The IAR compiler does not have full support for inline assembler, so
\r
64 * these are defined in the portmacro assembler file.
\r
66 extern void vPortYieldFromTick( void );
\r
67 extern void vPortStart( void );
\r
69 /*-----------------------------------------------------------*/
\r
72 * See header file for description.
\r
74 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
\r
77 StackType_t *pxTopOfHardwareStack;
\r
79 /* Place a few bytes of known values on the bottom of the stack.
\r
80 This is just useful for debugging. */
\r
82 *pxTopOfStack = 0x11;
\r
84 *pxTopOfStack = 0x22;
\r
86 *pxTopOfStack = 0x33;
\r
89 /* Remember where the top of the hardware stack is - this is required
\r
91 pxTopOfHardwareStack = pxTopOfStack;
\r
94 /* Simulate how the stack would look after a call to vPortYield(). */
\r
96 /*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */
\r
100 /* The IAR compiler requires two stacks per task. First there is the
\r
101 hardware call stack which uses the AVR stack pointer. Second there is the
\r
102 software stack (local variables, parameter passing, etc.) which uses the
\r
105 This function places both stacks within the memory block passed in as the
\r
106 first parameter. The hardware stack is placed at the bottom of the memory
\r
107 block. A gap is then left for the hardware stack to grow. Next the software
\r
108 stack is placed. The amount of space between the software and hardware
\r
109 stacks is defined by configCALL_STACK_SIZE.
\r
113 The first part of the stack is the hardware stack. Place the start
\r
114 address of the task on the hardware stack. */
\r
115 usAddress = ( uint16_t ) pxCode;
\r
116 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
120 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
124 /* Leave enough space for the hardware stack before starting the software
\r
125 stack. The '- 2' is because we have already used two spaces for the
\r
126 address of the start of the task. */
\r
127 pxTopOfStack -= ( configCALL_STACK_SIZE - 2 );
\r
131 /* Next simulate the stack as if after a call to portSAVE_CONTEXT().
\r
132 portSAVE_CONTEXT places the flags on the stack immediately after r0
\r
133 to ensure the interrupts get disabled as soon as possible, and so ensuring
\r
134 the stack use is minimal should a context switch interrupt occur. */
\r
135 *pxTopOfStack = ( StackType_t ) 0x00; /* R0 */
\r
137 *pxTopOfStack = portFLAGS_INT_ENABLED;
\r
140 /* Next place the address of the hardware stack. This is required so
\r
141 the AVR stack pointer can be restored to point to the hardware stack. */
\r
142 pxTopOfHardwareStack -= portBYTES_USED_BY_RETURN_ADDRESS;
\r
143 usAddress = ( uint16_t ) pxTopOfHardwareStack;
\r
146 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
151 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
157 /* Now the remaining registers. */
\r
158 *pxTopOfStack = ( StackType_t ) 0x01; /* R1 */
\r
160 *pxTopOfStack = ( StackType_t ) 0x02; /* R2 */
\r
162 *pxTopOfStack = ( StackType_t ) 0x03; /* R3 */
\r
164 *pxTopOfStack = ( StackType_t ) 0x04; /* R4 */
\r
166 *pxTopOfStack = ( StackType_t ) 0x05; /* R5 */
\r
168 *pxTopOfStack = ( StackType_t ) 0x06; /* R6 */
\r
170 *pxTopOfStack = ( StackType_t ) 0x07; /* R7 */
\r
172 *pxTopOfStack = ( StackType_t ) 0x08; /* R8 */
\r
174 *pxTopOfStack = ( StackType_t ) 0x09; /* R9 */
\r
176 *pxTopOfStack = ( StackType_t ) 0x10; /* R10 */
\r
178 *pxTopOfStack = ( StackType_t ) 0x11; /* R11 */
\r
180 *pxTopOfStack = ( StackType_t ) 0x12; /* R12 */
\r
182 *pxTopOfStack = ( StackType_t ) 0x13; /* R13 */
\r
184 *pxTopOfStack = ( StackType_t ) 0x14; /* R14 */
\r
186 *pxTopOfStack = ( StackType_t ) 0x15; /* R15 */
\r
189 /* Place the parameter on the stack in the expected location. */
\r
190 usAddress = ( uint16_t ) pvParameters;
\r
191 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
195 *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
\r
198 *pxTopOfStack = ( StackType_t ) 0x18; /* R18 */
\r
200 *pxTopOfStack = ( StackType_t ) 0x19; /* R19 */
\r
202 *pxTopOfStack = ( StackType_t ) 0x20; /* R20 */
\r
204 *pxTopOfStack = ( StackType_t ) 0x21; /* R21 */
\r
206 *pxTopOfStack = ( StackType_t ) 0x22; /* R22 */
\r
208 *pxTopOfStack = ( StackType_t ) 0x23; /* R23 */
\r
210 *pxTopOfStack = ( StackType_t ) 0x24; /* R24 */
\r
212 *pxTopOfStack = ( StackType_t ) 0x25; /* R25 */
\r
214 *pxTopOfStack = ( StackType_t ) 0x26; /* R26 X */
\r
216 *pxTopOfStack = ( StackType_t ) 0x27; /* R27 */
\r
219 /* The Y register is not stored as it is used as the software stack and
\r
220 gets saved into the task control block. */
\r
222 *pxTopOfStack = ( StackType_t ) 0x30; /* R30 Z */
\r
224 *pxTopOfStack = ( StackType_t ) 0x031; /* R31 */
\r
227 *pxTopOfStack = portNO_CRITICAL_NESTING; /* Critical nesting is zero when the task starts. */
\r
229 /*lint +e950 +e611 +e923 */
\r
231 return pxTopOfStack;
\r
233 /*-----------------------------------------------------------*/
\r
235 BaseType_t xPortStartScheduler( void )
\r
237 /* Setup the hardware to generate the tick. */
\r
238 prvSetupTimerInterrupt();
\r
240 /* Restore the context of the first task that is going to run.
\r
241 Normally we would just call portRESTORE_CONTEXT() here, but as the IAR
\r
242 compiler does not fully support inline assembler we have to make a call.*/
\r
245 /* Should not get here! */
\r
248 /*-----------------------------------------------------------*/
\r
250 void vPortEndScheduler( void )
\r
252 /* It is unlikely that the AVR port will get stopped. If required simply
\r
253 disable the tick interrupt here. */
\r
255 /*-----------------------------------------------------------*/
\r
258 * Setup timer 1 compare match A to generate a tick interrupt.
\r
260 static void prvSetupTimerInterrupt( void )
\r
262 uint32_t ulCompareMatch;
\r
263 uint8_t ucHighByte, ucLowByte;
\r
265 /* Using 16bit timer 1 to generate the tick. Correct fuses must be
\r
266 selected for the configCPU_CLOCK_HZ clock. */
\r
268 ulCompareMatch = configCPU_CLOCK_HZ / configTICK_RATE_HZ;
\r
270 /* We only have 16 bits so have to scale to get our required tick rate. */
\r
271 ulCompareMatch /= portCLOCK_PRESCALER;
\r
273 /* Adjust for correct value. */
\r
274 ulCompareMatch -= ( uint32_t ) 1;
\r
276 /* Setup compare match value for compare match A. Interrupts are disabled
\r
277 before this is called so we need not worry here. */
\r
278 ucLowByte = ( uint8_t ) ( ulCompareMatch & ( uint32_t ) 0xff );
\r
279 ulCompareMatch >>= 8;
\r
280 ucHighByte = ( uint8_t ) ( ulCompareMatch & ( uint32_t ) 0xff );
\r
281 OCR1AH = ucHighByte;
\r
282 OCR1AL = ucLowByte;
\r
284 /* Setup clock source and compare match behaviour. */
\r
285 ucLowByte = portCLEAR_COUNTER_ON_MATCH | portPRESCALE_64;
\r
286 TCCR1B = ucLowByte;
\r
288 /* Enable the interrupt - this is okay as interrupt are currently globally
\r
290 TIMSK |= portCOMPARE_MATCH_A_INTERRUPT_ENABLE;
\r
292 /*-----------------------------------------------------------*/
\r
294 #if configUSE_PREEMPTION == 1
\r
297 * Tick ISR for preemptive scheduler. We can use a __task attribute as
\r
298 * the context is saved at the start of vPortYieldFromTick(). The tick
\r
299 * count is incremented after the context is saved.
\r
301 __task void SIG_OUTPUT_COMPARE1A( void )
\r
303 vPortYieldFromTick();
\r
310 * Tick ISR for the cooperative scheduler. All this does is increment the
\r
311 * tick count. We don't need to switch context, this can only be done by
\r
312 * manual calls to taskYIELD();
\r
314 * THE INTERRUPT VECTOR IS POPULATED IN portmacro.s90. DO NOT INSTALL
\r
315 * IT HERE USING THE USUAL PRAGMA.
\r
317 __interrupt void SIG_OUTPUT_COMPARE1A( void )
\r
319 xTaskIncrementTick();
\r
322 /*-----------------------------------------------------------*/
\r
324 void vPortEnterCritical( void )
\r
326 portDISABLE_INTERRUPTS();
\r
327 uxCriticalNesting++;
\r
329 /*-----------------------------------------------------------*/
\r
331 void vPortExitCritical( void )
\r
333 uxCriticalNesting--;
\r
334 if( uxCriticalNesting == portNO_CRITICAL_NESTING )
\r
336 portENABLE_INTERRUPTS();
\r