forked from feilipu/miniAVRfreeRTOS
/
port.c
575 lines (509 loc) · 18.4 KB
/
port.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
/*
FreeRTOS V8.2.3 - Copyright (C) 2015 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
***************************************************************************
>>! NOTE: The modification to the GPL is included to allow you to !<<
>>! distribute a combined work that includes FreeRTOS without being !<<
>>! obliged to provide the source code for proprietary components !<<
>>! outside of the FreeRTOS kernel. !<<
***************************************************************************
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
#include <stdlib.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>
#include "FreeRTOS.h"
#include "task.h"
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the AVR port.
*----------------------------------------------------------*/
/* Start tasks with interrupts enabled. */
#define portFLAGS_INT_ENABLED ( (StackType_t) 0x80 )
#define portSCHEDULER_ISR WDT_vect
/*-----------------------------------------------------------*/
/* We require the address of the pxCurrentTCB variable, but don't want to know
any details of its type. */
typedef void TCB_t;
extern volatile TCB_t * volatile pxCurrentTCB;
/*-----------------------------------------------------------*/
/*
* Perform hardware setup to enable ticks from Watchdog Timer.
*/
static void prvSetupTimerInterrupt( void );
/*-----------------------------------------------------------*/
/*
* Macro to save all the general purpose registers, the save the stack pointer
* into the TCB.
*
* The first thing we do is save the flags then disable interrupts. This is to
* guard our stack against having a context switch interrupt after we have already
* pushed the registers onto the stack - causing the 32 registers to be on the
* stack twice.
*
* r1 is set to zero as the compiler expects it to be thus, however some
* of the math routines make use of R1.
*
* The interrupts will have been disabled during the call to portSAVE_CONTEXT()
* so we need not worry about reading/writing to the stack pointer.
*/
#if defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)
/* 3-Byte PC Save */
#define portSAVE_CONTEXT() \
__asm__ __volatile__ ( "push r0 \n\t" \
"in r0, __SREG__ \n\t" \
"cli \n\t" \
"push r0 \n\t" \
"in r0, 0x3b \n\t" \
"push r0 \n\t" \
"in r0, 0x3c \n\t" \
"push r0 \n\t" \
"push r1 \n\t" \
"clr r1 \n\t" \
"push r2 \n\t" \
"push r3 \n\t" \
"push r4 \n\t" \
"push r5 \n\t" \
"push r6 \n\t" \
"push r7 \n\t" \
"push r8 \n\t" \
"push r9 \n\t" \
"push r10 \n\t" \
"push r11 \n\t" \
"push r12 \n\t" \
"push r13 \n\t" \
"push r14 \n\t" \
"push r15 \n\t" \
"push r16 \n\t" \
"push r17 \n\t" \
"push r18 \n\t" \
"push r19 \n\t" \
"push r20 \n\t" \
"push r21 \n\t" \
"push r22 \n\t" \
"push r23 \n\t" \
"push r24 \n\t" \
"push r25 \n\t" \
"push r26 \n\t" \
"push r27 \n\t" \
"push r28 \n\t" \
"push r29 \n\t" \
"push r30 \n\t" \
"push r31 \n\t" \
"lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"in r0, 0x3d \n\t" \
"st x+, r0 \n\t" \
"in r0, 0x3e \n\t" \
"st x+, r0 \n\t" \
);
#else
/* 2-Byte PC Save */
#define portSAVE_CONTEXT() \
__asm__ __volatile__ ( "push r0 \n\t" \
"in r0, __SREG__ \n\t" \
"cli \n\t" \
"push r0 \n\t" \
"push r1 \n\t" \
"clr r1 \n\t" \
"push r2 \n\t" \
"push r3 \n\t" \
"push r4 \n\t" \
"push r5 \n\t" \
"push r6 \n\t" \
"push r7 \n\t" \
"push r8 \n\t" \
"push r9 \n\t" \
"push r10 \n\t" \
"push r11 \n\t" \
"push r12 \n\t" \
"push r13 \n\t" \
"push r14 \n\t" \
"push r15 \n\t" \
"push r16 \n\t" \
"push r17 \n\t" \
"push r18 \n\t" \
"push r19 \n\t" \
"push r20 \n\t" \
"push r21 \n\t" \
"push r22 \n\t" \
"push r23 \n\t" \
"push r24 \n\t" \
"push r25 \n\t" \
"push r26 \n\t" \
"push r27 \n\t" \
"push r28 \n\t" \
"push r29 \n\t" \
"push r30 \n\t" \
"push r31 \n\t" \
"lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"in r0, 0x3d \n\t" \
"st x+, r0 \n\t" \
"in r0, 0x3e \n\t" \
"st x+, r0 \n\t" \
);
#endif
/*
* Opposite to portSAVE_CONTEXT(). Interrupts will have been disabled during
* the context save so we can write to the stack pointer.
*/
#if defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)
/* 3-Byte PC Restore */
#define portRESTORE_CONTEXT() \
__asm__ __volatile__ ( "lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"ld r28, x+ \n\t" \
"out __SP_L__, r28 \n\t" \
"ld r29, x+ \n\t" \
"out __SP_H__, r29 \n\t" \
"pop r31 \n\t" \
"pop r30 \n\t" \
"pop r29 \n\t" \
"pop r28 \n\t" \
"pop r27 \n\t" \
"pop r26 \n\t" \
"pop r25 \n\t" \
"pop r24 \n\t" \
"pop r23 \n\t" \
"pop r22 \n\t" \
"pop r21 \n\t" \
"pop r20 \n\t" \
"pop r19 \n\t" \
"pop r18 \n\t" \
"pop r17 \n\t" \
"pop r16 \n\t" \
"pop r15 \n\t" \
"pop r14 \n\t" \
"pop r13 \n\t" \
"pop r12 \n\t" \
"pop r11 \n\t" \
"pop r10 \n\t" \
"pop r9 \n\t" \
"pop r8 \n\t" \
"pop r7 \n\t" \
"pop r6 \n\t" \
"pop r5 \n\t" \
"pop r4 \n\t" \
"pop r3 \n\t" \
"pop r2 \n\t" \
"pop r1 \n\t" \
"pop r0 \n\t" \
"out 0x3c, r0 \n\t" \
"pop r0 \n\t" \
"out 0x3b, r0 \n\t" \
"pop r0 \n\t" \
"out __SREG__, r0 \n\t" \
"pop r0 \n\t" \
);
#else
/* 2-Byte PC Restore */
#define portRESTORE_CONTEXT() \
__asm__ __volatile__ ( "lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"ld r28, x+ \n\t" \
"out __SP_L__, r28 \n\t" \
"ld r29, x+ \n\t" \
"out __SP_H__, r29 \n\t" \
"pop r31 \n\t" \
"pop r30 \n\t" \
"pop r29 \n\t" \
"pop r28 \n\t" \
"pop r27 \n\t" \
"pop r26 \n\t" \
"pop r25 \n\t" \
"pop r24 \n\t" \
"pop r23 \n\t" \
"pop r22 \n\t" \
"pop r21 \n\t" \
"pop r20 \n\t" \
"pop r19 \n\t" \
"pop r18 \n\t" \
"pop r17 \n\t" \
"pop r16 \n\t" \
"pop r15 \n\t" \
"pop r14 \n\t" \
"pop r13 \n\t" \
"pop r12 \n\t" \
"pop r11 \n\t" \
"pop r10 \n\t" \
"pop r9 \n\t" \
"pop r8 \n\t" \
"pop r7 \n\t" \
"pop r6 \n\t" \
"pop r5 \n\t" \
"pop r4 \n\t" \
"pop r3 \n\t" \
"pop r2 \n\t" \
"pop r1 \n\t" \
"pop r0 \n\t" \
"out __SREG__, r0 \n\t" \
"pop r0 \n\t" \
);
#endif
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
uint16_t usAddress;
/* Place a few bytes of known values on the bottom of the stack.
This is just useful for debugging. */
*pxTopOfStack = 0x11;
pxTopOfStack--;
*pxTopOfStack = 0x22;
pxTopOfStack--;
*pxTopOfStack = 0x33;
pxTopOfStack--;
/* Simulate how the stack would look after a call to vPortYield() generated by
the compiler. */
/* The start of the task code will be popped off the stack last, so place
it on first. */
#if defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)
/* The AVR ATmega2560/ATmega2561 have 256KBytes of program memory and a 17-bit
* program counter. When a code address is stored on the stack, it takes 3 bytes
* instead of 2 for the other ATmega* chips.
*
* Store 0 as the top byte since we force all task routines to the bottom 128K
* of flash. We do this by using the .lowtext label in the linker script.
*
* In order to do this properly, we would need to get a full 3-byte pointer to
* pxCode. That requires a change to GCC. Not likely to happen any time soon.
*/
usAddress = ( uint16_t ) pxCode;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
usAddress >>= 8;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
*pxTopOfStack = 0;
pxTopOfStack--;
#else
usAddress = ( uint16_t ) pxCode;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
usAddress >>= 8;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
#endif
/* Next simulate the stack as if after a call to portSAVE_CONTEXT().
portSAVE_CONTEXT places the flags on the stack immediately after r0
to ensure the interrupts get disabled as soon as possible, and so ensuring
the stack use is minimal should a context switch interrupt occur. */
*pxTopOfStack = ( StackType_t ) 0x00; /* R0 */
pxTopOfStack--;
*pxTopOfStack = portFLAGS_INT_ENABLED;
pxTopOfStack--;
#if defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)
/* If we have an ATmega256x, we are also saving the RAMPZ and EIND registers.
* We should default those to 0.
*/
*pxTopOfStack = ( StackType_t ) 0x00; /* EIND */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x00; /* RAMPZ */
pxTopOfStack--;
#endif
/* Now the remaining registers. The compiler expects R1 to be 0. */
*pxTopOfStack = ( StackType_t ) 0x00; /* R1 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x02; /* R2 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x03; /* R3 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x04; /* R4 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x05; /* R5 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x06; /* R6 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x07; /* R7 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x08; /* R8 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x09; /* R9 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x10; /* R10 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x11; /* R11 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x12; /* R12 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x13; /* R13 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x14; /* R14 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x15; /* R15 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x16; /* R16 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x17; /* R17 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x18; /* R18 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x19; /* R19 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x20; /* R20 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x21; /* R21 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x22; /* R22 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x23; /* R23 */
pxTopOfStack--;
/* Place the parameter on the stack in the expected location. */
usAddress = ( uint16_t ) pvParameters;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
usAddress >>= 8;
*pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x26; /* R26 X */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x27; /* R27 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x28; /* R28 Y */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x29; /* R29 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x30; /* R30 Z */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0x031; /* R31 */
pxTopOfStack--;
/*lint +e950 +e611 +e923 */
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
BaseType_t xPortStartScheduler( void )
{
/* Setup the relevant timer hardware to generate the tick. */
prvSetupTimerInterrupt();
/* Restore the context of the first task that is going to run. */
portRESTORE_CONTEXT();
/* Simulate a function call end as generated by the compiler. We will now
jump to the start of the task the context of which we have just restored. */
__asm__ __volatile__ ( "ret" );
/* Should not get here. */
return pdTRUE;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
/* It is unlikely that the AVR port will get stopped. If required simply
disable the tick interrupt here. */
wdt_disable(); // disable Watchdog Timer
}
/*-----------------------------------------------------------*/
/*
* Manual context switch. The first thing we do is save the registers so we
* can use a naked attribute.
*/
void vPortYield( void ) __attribute__ ( ( hot, flatten, naked ) );
void vPortYield( void )
{
portSAVE_CONTEXT();
vTaskSwitchContext();
portRESTORE_CONTEXT();
__asm__ __volatile__ ( "ret" );
}
/*-----------------------------------------------------------*/
/*
* Context switch function used by the tick. This must be identical to
* vPortYield() from the call to vTaskSwitchContext() onwards. The only
* difference from vPortYield() is the tick count is incremented as the
* call comes from the tick ISR.
*/
void vPortYieldFromTick( void ) __attribute__ ( ( hot, flatten, naked ) );
void vPortYieldFromTick( void )
{
portSAVE_CONTEXT();
if( xTaskIncrementTick() != pdFALSE )
{
vTaskSwitchContext();
}
portRESTORE_CONTEXT();
__asm__ __volatile__ ( "ret" );
}
/*-----------------------------------------------------------*/
//initialize watchdog
void prvSetupTimerInterrupt( void )
{
//reset watchdog
wdt_reset();
//set up WDT Interrupt (rather than the WDT Reset).
wdt_interrupt_enable( portUSE_WDTO );
}
/*-----------------------------------------------------------*/
#if configUSE_PREEMPTION == 1
/*
* Tick ISR for preemptive scheduler. We can use a naked attribute as
* the context is saved at the start of vPortYieldFromTick(). The tick
* count is incremented after the context is saved.
*
* use ISR_NOBLOCK where there is an important timer running, that should preempt the scheduler.
*
*/
// ISR(portSCHEDULER_ISR, ISR_NAKED ISR_NOBLOCK)
ISR(portSCHEDULER_ISR, ISR_NAKED) __attribute__ ((hot, flatten));
ISR(portSCHEDULER_ISR, ISR_NAKED)
{
vPortYieldFromTick();
__asm__ __volatile__ ( "reti" );
}
#else
/*
* Tick ISR for the cooperative scheduler. All this does is increment the
* tick count. We don't need to switch context, this can only be done by
* manual calls to taskYIELD();
*
* use ISR_NOBLOCK where there is an important timer running, that should preempt the scheduler.
*/
// ISR(portSCHEDULER_ISR, ISR_NOBLOCK)
ISR(portSCHEDULER_ISR) __attribute__ ((hot, flatten));
ISR(portSCHEDULER_ISR)
{
xTaskIncrementTick();
}
#endif // configUSE_PREEMPTION