1 /*
2 * FreeRTOS Kernel V10.6.2
3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4 *
5 * SPDX-License-Identifier: MIT
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy of
8 * this software and associated documentation files (the "Software"), to deal in
9 * the Software without restriction, including without limitation the rights to
10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
11 * the Software, and to permit persons to whom the Software is furnished to do so,
12 * subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in all
15 * copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * https://www.FreeRTOS.org
25 * https://github.com/FreeRTOS
26 *
27 */
28
29 /*
30 Changes from V3.2.1
31 + CallReturn Depth increased from 8 to 10 levels to accomodate wizC/fedC V12.
32
33 Changes from V3.2.0
34 + TBLPTRU is now initialised to zero during the initial stack creation of a new task. This solves
35 an error on devices with more than 64kB ROM.
36
37 Changes from V3.0.0
38 + ucCriticalNesting is now initialised to 0x7F to prevent interrupts from being
39 handled before the scheduler is started.
40
41 Changes from V3.0.1
42 */
43
44 /* Scheduler include files. */
45 #include <FreeRTOS.h>
46 #include <task.h>
47
48 #include <malloc.h>
49
50 /*---------------------------------------------------------------------------
51 * Implementation of functions defined in portable.h for the WizC PIC18 port.
52 *---------------------------------------------------------------------------*/
53
54 /*
55 * We require the address of the pxCurrentTCB variable, but don't want to
56 * know any details of its type.
57 */
58 typedef void TCB_t;
59 extern volatile TCB_t * volatile pxCurrentTCB;
60
61 /*
62 * Define minimal-stack constants
63 * -----
64 * FSR's:
65 * STATUS, WREG, BSR, PRODH, PRODL, FSR0H, FSR0L,
66 * FSR1H, FSR1L,TABLAT, (TBLPTRU), TBLPTRH, TBLPTRL,
67 * (PCLATU), PCLATH
68 * sfr's within parenthesis only on devices > 64kB
69 * -----
70 * Call/Return stack:
71 * 2 bytes per entry on devices <= 64kB
72 * 3 bytes per entry on devices > 64kB
73 * -----
74 * Other bytes:
75 * 2 bytes: FunctionParameter for initial taskcode
76 * 1 byte : Number of entries on call/return stack
77 * 1 byte : ucCriticalNesting
78 * 16 bytes: Free space on stack
79 */
80 #if _ROMSIZE > 0x8000
81 #define portSTACK_FSR_BYTES ( 15 )
82 #define portSTACK_CALLRETURN_ENTRY_SIZE ( 3 )
83 #else
84 #define portSTACK_FSR_BYTES ( 13 )
85 #define portSTACK_CALLRETURN_ENTRY_SIZE ( 2 )
86 #endif
87
88 #define portSTACK_MINIMAL_CALLRETURN_DEPTH ( 10 )
89 #define portSTACK_OTHER_BYTES ( 20 )
90
91 uint16_t usCalcMinStackSize = 0;
92
93 /*-----------------------------------------------------------*/
94
95 /*
96 * We initialise ucCriticalNesting to the middle value an
97 * uint8_t can contain. This way portENTER_CRITICAL()
98 * and portEXIT_CRITICAL() can be called without interrupts
99 * being enabled before the scheduler starts.
100 */
101 register uint8_t ucCriticalNesting = 0x7F;
102
103 /*-----------------------------------------------------------*/
104
105 /*
106 * Initialise the stack of a new task.
107 * See portSAVE_CONTEXT macro for description.
108 */
pxPortInitialiseStack(StackType_t * pxTopOfStack,TaskFunction_t pxCode,void * pvParameters)109 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
110 {
111 uint8_t ucScratch;
112 /*
113 * Get the size of the RAMarea in page 0 used by the compiler
114 * We do this here already to avoid W-register conflicts.
115 */
116 _Pragma("asm")
117 movlw OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE
118 movwf PRODL,ACCESS ; PRODL is used as temp register
119 _Pragma("asmend")
120 ucScratch = PRODL;
121
122 /*
123 * Place a few bytes of known values on the bottom of the stack.
124 * This is just useful for debugging.
125 */
126 // *pxTopOfStack-- = 0x11;
127 // *pxTopOfStack-- = 0x22;
128 // *pxTopOfStack-- = 0x33;
129
130 /*
131 * Simulate how the stack would look after a call to vPortYield()
132 * generated by the compiler.
133 */
134
135 /*
136 * First store the function parameters. This is where the task expects
137 * to find them when it starts running.
138 */
139 *pxTopOfStack-- = ( StackType_t ) ( (( uint16_t ) pvParameters >> 8) & 0x00ff );
140 *pxTopOfStack-- = ( StackType_t ) ( ( uint16_t ) pvParameters & 0x00ff );
141
142 /*
143 * Next are all the registers that form part of the task context.
144 */
145 *pxTopOfStack-- = ( StackType_t ) 0x11; /* STATUS. */
146 *pxTopOfStack-- = ( StackType_t ) 0x22; /* WREG. */
147 *pxTopOfStack-- = ( StackType_t ) 0x33; /* BSR. */
148 *pxTopOfStack-- = ( StackType_t ) 0x44; /* PRODH. */
149 *pxTopOfStack-- = ( StackType_t ) 0x55; /* PRODL. */
150 *pxTopOfStack-- = ( StackType_t ) 0x66; /* FSR0H. */
151 *pxTopOfStack-- = ( StackType_t ) 0x77; /* FSR0L. */
152 *pxTopOfStack-- = ( StackType_t ) 0x88; /* FSR1H. */
153 *pxTopOfStack-- = ( StackType_t ) 0x99; /* FSR1L. */
154 *pxTopOfStack-- = ( StackType_t ) 0xAA; /* TABLAT. */
155 #if _ROMSIZE > 0x8000
156 *pxTopOfStack-- = ( StackType_t ) 0x00; /* TBLPTRU. */
157 #endif
158 *pxTopOfStack-- = ( StackType_t ) 0xCC; /* TBLPTRH. */
159 *pxTopOfStack-- = ( StackType_t ) 0xDD; /* TBLPTRL. */
160 #if _ROMSIZE > 0x8000
161 *pxTopOfStack-- = ( StackType_t ) 0xEE; /* PCLATU. */
162 #endif
163 *pxTopOfStack-- = ( StackType_t ) 0xFF; /* PCLATH. */
164
165 /*
166 * Next the compiler's scratchspace.
167 */
168 while(ucScratch-- > 0)
169 {
170 *pxTopOfStack-- = ( StackType_t ) 0;
171 }
172
173 /*
174 * The only function return address so far is the address of the task entry.
175 * The order is TOSU/TOSH/TOSL. For devices > 64kB, TOSU is put on the
176 * stack, too. TOSU is always written as zero here because wizC does not allow
177 * functionpointers to point above 64kB in ROM.
178 */
179 #if _ROMSIZE > 0x8000
180 *pxTopOfStack-- = ( StackType_t ) 0;
181 #endif
182 *pxTopOfStack-- = ( StackType_t ) ( ( ( uint16_t ) pxCode >> 8 ) & 0x00ff );
183 *pxTopOfStack-- = ( StackType_t ) ( ( uint16_t ) pxCode & 0x00ff );
184
185 /*
186 * Store the number of return addresses on the hardware stack.
187 * So far only the address of the task entry point.
188 */
189 *pxTopOfStack-- = ( StackType_t ) 1;
190
191 /*
192 * The code generated by wizC does not maintain separate
193 * stack and frame pointers. Therefore the portENTER_CRITICAL macro cannot
194 * use the stack as per other ports. Instead a variable is used to keep
195 * track of the critical section nesting. This variable has to be stored
196 * as part of the task context and is initially set to zero.
197 */
198 *pxTopOfStack-- = ( StackType_t ) portNO_CRITICAL_SECTION_NESTING;
199
200 return pxTopOfStack;
201 }
202 /*-----------------------------------------------------------*/
203
usPortCALCULATE_MINIMAL_STACK_SIZE(void)204 uint16_t usPortCALCULATE_MINIMAL_STACK_SIZE( void )
205 {
206 /*
207 * Fetch the size of compiler's scratchspace.
208 */
209 _Pragma("asm")
210 movlw OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE
211 movlb usCalcMinStackSize>>8
212 movwf usCalcMinStackSize,BANKED
213 _Pragma("asmend")
214
215 /*
216 * Add minimum needed stackspace
217 */
218 usCalcMinStackSize += ( portSTACK_FSR_BYTES )
219 + ( portSTACK_MINIMAL_CALLRETURN_DEPTH * portSTACK_CALLRETURN_ENTRY_SIZE )
220 + ( portSTACK_OTHER_BYTES );
221
222 return(usCalcMinStackSize);
223 }
224
225 /*-----------------------------------------------------------*/
226
xPortStartScheduler(void)227 BaseType_t xPortStartScheduler( void )
228 {
229 extern void portSetupTick( void );
230
231 /*
232 * Setup a timer for the tick ISR for the preemptive scheduler.
233 */
234 portSetupTick();
235
236 /*
237 * Restore the context of the first task to run.
238 */
239 portRESTORE_CONTEXT();
240
241 /*
242 * This point should never be reached during execution.
243 */
244 return pdTRUE;
245 }
246
247 /*-----------------------------------------------------------*/
248
vPortEndScheduler(void)249 void vPortEndScheduler( void )
250 {
251 /*
252 * It is unlikely that the scheduler for the PIC port will get stopped
253 * once running. When called a reset is done which is probably the
254 * most valid action.
255 */
256 _Pragma(asmline reset);
257 }
258
259 /*-----------------------------------------------------------*/
260
261 /*
262 * Manual context switch. This is similar to the tick context switch,
263 * but does not increment the tick count. It must be identical to the
264 * tick context switch in how it stores the stack of a task.
265 */
vPortYield(void)266 void vPortYield( void )
267 {
268 /*
269 * Save the context of the current task.
270 */
271 portSAVE_CONTEXT( portINTERRUPTS_UNCHANGED );
272
273 /*
274 * Switch to the highest priority task that is ready to run.
275 */
276 vTaskSwitchContext();
277
278 /*
279 * Start executing the task we have just switched to.
280 */
281 portRESTORE_CONTEXT();
282 }
283 /*-----------------------------------------------------------*/
284
285 #if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
286
pvPortMalloc(uint16_t usWantedSize)287 void *pvPortMalloc( uint16_t usWantedSize )
288 {
289 void *pvReturn;
290
291 vTaskSuspendAll();
292 {
293 pvReturn = malloc( ( malloc_t ) usWantedSize );
294 }
295 xTaskResumeAll();
296
297 return pvReturn;
298 }
299
300 #endif /* configSUPPORT_STATIC_ALLOCATION */
301
302 /*-----------------------------------------------------------*/
303
304 #if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
305
vPortFree(void * pv)306 void vPortFree( void *pv )
307 {
308 if( pv )
309 {
310 vTaskSuspendAll();
311 {
312 free( pv );
313 }
314 xTaskResumeAll();
315 }
316 }
317
318 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
319
