1 /*
2 * FreeRTOS Kernel V11.1.0
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 * Implementation of functions defined in portable.h for the RX600 port.
31 *----------------------------------------------------------*/
32
33 /* Scheduler includes. */
34 #include "FreeRTOS.h"
35 #include "task.h"
36
37 /* Library includes. */
38 #include "string.h"
39
40 /* Hardware specifics. */
41 #include "iodefine.h"
42
43 /*-----------------------------------------------------------*/
44
45 /* Tasks should start with interrupts enabled and in Supervisor mode, therefore
46 PSW is set with U and I set, and PM and IPL clear. */
47 #define portINITIAL_PSW ( ( StackType_t ) 0x00030000 )
48 #define portINITIAL_FPSW ( ( StackType_t ) 0x00000100 )
49
50 /*-----------------------------------------------------------*/
51
52 /* The following lines are to ensure vSoftwareInterruptEntry can be referenced,
53 and therefore installed in the vector table, when the FreeRTOS code is built
54 as a library. */
55 extern BaseType_t vSoftwareInterruptEntry;
56 const BaseType_t * p_vSoftwareInterruptEntry = &vSoftwareInterruptEntry;
57
58 /*-----------------------------------------------------------*/
59
60 /*
61 * Function to start the first task executing - written in asm code as direct
62 * access to registers is required.
63 */
64 static void prvStartFirstTask( void );
65
66 /*
67 * Software interrupt handler. Performs the actual context switch (saving and
68 * restoring of registers). Written in asm code as direct register access is
69 * required.
70 */
71 static void prvYieldHandler( void );
72
73 /*
74 * The entry point for the software interrupt handler. This is the function
75 * that calls the inline asm function prvYieldHandler(). It is installed in
76 * the vector table, but the code that installs it is in prvYieldHandler rather
77 * than using a #pragma.
78 */
79 void vSoftwareInterruptISR( void );
80
81 /*-----------------------------------------------------------*/
82
83 /* This is accessed by the inline assembler functions so is file scope for
84 convenience. */
85 extern void *pxCurrentTCB;
86 extern void vTaskSwitchContext( void );
87
88 /*-----------------------------------------------------------*/
89
90 /*
91 * See header file for description.
92 */
pxPortInitialiseStack(StackType_t * pxTopOfStack,TaskFunction_t pxCode,void * pvParameters)93 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
94 {
95 /* R0 is not included as it is the stack pointer. */
96
97 *pxTopOfStack = 0x00;
98 pxTopOfStack--;
99 *pxTopOfStack = portINITIAL_PSW;
100 pxTopOfStack--;
101 *pxTopOfStack = ( StackType_t ) pxCode;
102
103 /* When debugging it can be useful if every register is set to a known
104 value. Otherwise code space can be saved by just setting the registers
105 that need to be set. */
106 #ifdef USE_FULL_REGISTER_INITIALISATION
107 {
108 pxTopOfStack--;
109 *pxTopOfStack = 0xffffffff; /* r15. */
110 pxTopOfStack--;
111 *pxTopOfStack = 0xeeeeeeee;
112 pxTopOfStack--;
113 *pxTopOfStack = 0xdddddddd;
114 pxTopOfStack--;
115 *pxTopOfStack = 0xcccccccc;
116 pxTopOfStack--;
117 *pxTopOfStack = 0xbbbbbbbb;
118 pxTopOfStack--;
119 *pxTopOfStack = 0xaaaaaaaa;
120 pxTopOfStack--;
121 *pxTopOfStack = 0x99999999;
122 pxTopOfStack--;
123 *pxTopOfStack = 0x88888888;
124 pxTopOfStack--;
125 *pxTopOfStack = 0x77777777;
126 pxTopOfStack--;
127 *pxTopOfStack = 0x66666666;
128 pxTopOfStack--;
129 *pxTopOfStack = 0x55555555;
130 pxTopOfStack--;
131 *pxTopOfStack = 0x44444444;
132 pxTopOfStack--;
133 *pxTopOfStack = 0x33333333;
134 pxTopOfStack--;
135 *pxTopOfStack = 0x22222222;
136 pxTopOfStack--;
137 }
138 #else
139 {
140 pxTopOfStack -= 15;
141 }
142 #endif
143
144 *pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
145 pxTopOfStack--;
146 *pxTopOfStack = portINITIAL_FPSW;
147 pxTopOfStack--;
148 *pxTopOfStack = 0x12345678; /* Accumulator. */
149 pxTopOfStack--;
150 *pxTopOfStack = 0x87654321; /* Accumulator. */
151
152 return pxTopOfStack;
153 }
154 /*-----------------------------------------------------------*/
155
xPortStartScheduler(void)156 BaseType_t xPortStartScheduler( void )
157 {
158 extern void vApplicationSetupTimerInterrupt( void );
159
160 /* Use pxCurrentTCB just so it does not get optimised away. */
161 if( pxCurrentTCB != NULL )
162 {
163 /* Call an application function to set up the timer that will generate the
164 tick interrupt. This way the application can decide which peripheral to
165 use. A demo application is provided to show a suitable example. */
166 vApplicationSetupTimerInterrupt();
167
168 /* Enable the software interrupt. */
169 _IEN( _ICU_SWINT ) = 1;
170
171 /* Ensure the software interrupt is clear. */
172 _IR( _ICU_SWINT ) = 0;
173
174 /* Ensure the software interrupt is set to the kernel priority. */
175 _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
176
177 /* Start the first task. */
178 prvStartFirstTask();
179 }
180
181 /* Just to make sure the function is not optimised away. */
182 ( void ) vSoftwareInterruptISR();
183
184 /* Should not get here. */
185 return pdFAIL;
186 }
187 /*-----------------------------------------------------------*/
188
189 #pragma inline_asm prvStartFirstTask
prvStartFirstTask(void)190 static void prvStartFirstTask( void )
191 {
192 /* When starting the scheduler there is nothing that needs moving to the
193 interrupt stack because the function is not called from an interrupt.
194 Just ensure the current stack is the user stack. */
195 SETPSW U
196
197 /* Obtain the location of the stack associated with which ever task
198 pxCurrentTCB is currently pointing to. */
199 MOV.L #_pxCurrentTCB, R15
200 MOV.L [R15], R15
201 MOV.L [R15], R0
202
203 /* Restore the registers from the stack of the task pointed to by
204 pxCurrentTCB. */
205 POP R15
206 MVTACLO R15 /* Accumulator low 32 bits. */
207 POP R15
208 MVTACHI R15 /* Accumulator high 32 bits. */
209 POP R15
210 MVTC R15,FPSW /* Floating point status word. */
211 POPM R1-R15 /* R1 to R15 - R0 is not included as it is the SP. */
212 RTE /* This pops the remaining registers. */
213 NOP
214 NOP
215 }
216 /*-----------------------------------------------------------*/
217
218 #pragma interrupt ( vTickISR( vect = _VECT( configTICK_VECTOR ), enable ) )
vTickISR(void)219 void vTickISR( void )
220 {
221 /* Increment the tick, and perform any processing the new tick value
222 necessitates. */
223 set_ipl( configMAX_SYSCALL_INTERRUPT_PRIORITY );
224 {
225 if( xTaskIncrementTick() != pdFALSE )
226 {
227 taskYIELD();
228 }
229 }
230 set_ipl( configKERNEL_INTERRUPT_PRIORITY );
231 }
232 /*-----------------------------------------------------------*/
233
vSoftwareInterruptISR(void)234 void vSoftwareInterruptISR( void )
235 {
236 prvYieldHandler();
237 }
238 /*-----------------------------------------------------------*/
239
240 #pragma inline_asm prvYieldHandler
prvYieldHandler(void)241 static void prvYieldHandler( void )
242 {
243 /* Re-enable interrupts. */
244 SETPSW I
245
246 /* Move the data that was automatically pushed onto the interrupt stack when
247 the interrupt occurred from the interrupt stack to the user stack.
248
249 R15 is saved before it is clobbered. */
250 PUSH.L R15
251
252 /* Read the user stack pointer. */
253 MVFC USP, R15
254
255 /* Move the address down to the data being moved. */
256 SUB #12, R15
257 MVTC R15, USP
258
259 /* Copy the data across. */
260 MOV.L [ R0 ], [ R15 ] ; R15
261 MOV.L 4[ R0 ], 4[ R15 ] ; PC
262 MOV.L 8[ R0 ], 8[ R15 ] ; PSW
263
264 /* Move the interrupt stack pointer to its new correct position. */
265 ADD #12, R0
266
267 /* All the rest of the registers are saved directly to the user stack. */
268 SETPSW U
269
270 /* Save the rest of the general registers (R15 has been saved already). */
271 PUSHM R1-R14
272
273 /* Save the FPSW and accumulator. */
274 MVFC FPSW, R15
275 PUSH.L R15
276 MVFACHI R15
277 PUSH.L R15
278 MVFACMI R15 ; Middle order word.
279 SHLL #16, R15 ; Shifted left as it is restored to the low order word.
280 PUSH.L R15
281
282 /* Save the stack pointer to the TCB. */
283 MOV.L #_pxCurrentTCB, R15
284 MOV.L [ R15 ], R15
285 MOV.L R0, [ R15 ]
286
287 /* Ensure the interrupt mask is set to the syscall priority while the kernel
288 structures are being accessed. */
289 MVTIPL #configMAX_SYSCALL_INTERRUPT_PRIORITY
290
291 /* Select the next task to run. */
292 BSR.A _vTaskSwitchContext
293
294 /* Reset the interrupt mask as no more data structure access is required. */
295 MVTIPL #configKERNEL_INTERRUPT_PRIORITY
296
297 /* Load the stack pointer of the task that is now selected as the Running
298 state task from its TCB. */
299 MOV.L #_pxCurrentTCB,R15
300 MOV.L [ R15 ], R15
301 MOV.L [ R15 ], R0
302
303 /* Restore the context of the new task. The PSW (Program Status Word) and
304 PC will be popped by the RTE instruction. */
305 POP R15
306 MVTACLO R15
307 POP R15
308 MVTACHI R15
309 POP R15
310 MVTC R15,FPSW
311 POPM R1-R15
312 RTE
313 NOP
314 NOP
315 }
316 /*-----------------------------------------------------------*/
317
vPortEndScheduler(void)318 void vPortEndScheduler( void )
319 {
320 /* Not implemented in ports where there is nothing to return to.
321 Artificially force an assert. */
322 configASSERT( pxCurrentTCB == NULL );
323
324 /* The following line is just to prevent the symbol getting optimised away. */
325 ( void ) vTaskSwitchContext();
326 }
327 /*-----------------------------------------------------------*/
328
