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 * Implementation of functions defined in portable.h for the SH2A port.
31 *----------------------------------------------------------*/
32
33 /* Scheduler includes. */
34 #include "FreeRTOS.h"
35 #include "task.h"
36
37 /* Library includes. */
38 #include "string.h"
39
40 /*-----------------------------------------------------------*/
41
42 /* The SR assigned to a newly created task. The only important thing in this
43 value is for all interrupts to be enabled. */
44 #define portINITIAL_SR ( 0UL )
45
46 /* Dimensions the array into which the floating point context is saved.
47 Allocate enough space for FPR0 to FPR15, FPUL and FPSCR, each of which is 4
48 bytes big. If this number is changed then the 72 in portasm.src also needs
49 changing. */
50 #define portFLOP_REGISTERS_TO_STORE ( 18 )
51 #define portFLOP_STORAGE_SIZE ( portFLOP_REGISTERS_TO_STORE * 4 )
52
53 #if( configSUPPORT_DYNAMIC_ALLOCATION == 0 )
54 #error configSUPPORT_DYNAMIC_ALLOCATION must be 1 to use this port.
55 #endif
56
57 /*-----------------------------------------------------------*/
58
59 /*
60 * The TRAPA handler used to force a context switch.
61 */
62 void vPortYield( void );
63
64 /*
65 * Function to start the first task executing - defined in portasm.src.
66 */
67 extern void vPortStartFirstTask( void );
68
69 /*
70 * Obtains the current GBR value - defined in portasm.src.
71 */
72 extern uint32_t ulPortGetGBR( void );
73
74 /*-----------------------------------------------------------*/
75
76 /*
77 * See header file for description.
78 */
pxPortInitialiseStack(StackType_t * pxTopOfStack,TaskFunction_t pxCode,void * pvParameters)79 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
80 {
81 /* Mark the end of the stack - used for debugging only and can be removed. */
82 *pxTopOfStack = 0x11111111UL;
83 pxTopOfStack--;
84 *pxTopOfStack = 0x22222222UL;
85 pxTopOfStack--;
86 *pxTopOfStack = 0x33333333UL;
87 pxTopOfStack--;
88
89 /* SR. */
90 *pxTopOfStack = portINITIAL_SR;
91 pxTopOfStack--;
92
93 /* PC. */
94 *pxTopOfStack = ( uint32_t ) pxCode;
95 pxTopOfStack--;
96
97 /* PR. */
98 *pxTopOfStack = 15;
99 pxTopOfStack--;
100
101 /* 14. */
102 *pxTopOfStack = 14;
103 pxTopOfStack--;
104
105 /* R13. */
106 *pxTopOfStack = 13;
107 pxTopOfStack--;
108
109 /* R12. */
110 *pxTopOfStack = 12;
111 pxTopOfStack--;
112
113 /* R11. */
114 *pxTopOfStack = 11;
115 pxTopOfStack--;
116
117 /* R10. */
118 *pxTopOfStack = 10;
119 pxTopOfStack--;
120
121 /* R9. */
122 *pxTopOfStack = 9;
123 pxTopOfStack--;
124
125 /* R8. */
126 *pxTopOfStack = 8;
127 pxTopOfStack--;
128
129 /* R7. */
130 *pxTopOfStack = 7;
131 pxTopOfStack--;
132
133 /* R6. */
134 *pxTopOfStack = 6;
135 pxTopOfStack--;
136
137 /* R5. */
138 *pxTopOfStack = 5;
139 pxTopOfStack--;
140
141 /* R4. */
142 *pxTopOfStack = ( uint32_t ) pvParameters;
143 pxTopOfStack--;
144
145 /* R3. */
146 *pxTopOfStack = 3;
147 pxTopOfStack--;
148
149 /* R2. */
150 *pxTopOfStack = 2;
151 pxTopOfStack--;
152
153 /* R1. */
154 *pxTopOfStack = 1;
155 pxTopOfStack--;
156
157 /* R0 */
158 *pxTopOfStack = 0;
159 pxTopOfStack--;
160
161 /* MACL. */
162 *pxTopOfStack = 16;
163 pxTopOfStack--;
164
165 /* MACH. */
166 *pxTopOfStack = 17;
167 pxTopOfStack--;
168
169 /* GBR. */
170 *pxTopOfStack = ulPortGetGBR();
171
172 /* GBR = global base register.
173 VBR = vector base register.
174 TBR = jump table base register.
175 R15 is the stack pointer. */
176
177 return pxTopOfStack;
178 }
179 /*-----------------------------------------------------------*/
180
xPortStartScheduler(void)181 BaseType_t xPortStartScheduler( void )
182 {
183 extern void vApplicationSetupTimerInterrupt( void );
184
185 /* Call an application function to set up the timer that will generate the
186 tick interrupt. This way the application can decide which peripheral to
187 use. A demo application is provided to show a suitable example. */
188 vApplicationSetupTimerInterrupt();
189
190 /* Start the first task. This will only restore the standard registers and
191 not the flop registers. This does not really matter though because the only
192 flop register that is initialised to a particular value is fpscr, and it is
193 only initialised to the current value, which will still be the current value
194 when the first task starts executing. */
195 trapa( portSTART_SCHEDULER_TRAP_NO );
196
197 /* Should not get here. */
198 return pdFAIL;
199 }
200 /*-----------------------------------------------------------*/
201
vPortEndScheduler(void)202 void vPortEndScheduler( void )
203 {
204 /* Not implemented as there is nothing to return to. */
205 }
206 /*-----------------------------------------------------------*/
207
vPortYield(void)208 void vPortYield( void )
209 {
210 int32_t lInterruptMask;
211
212 /* Ensure the yield trap runs at the same priority as the other interrupts
213 that can cause a context switch. */
214 lInterruptMask = get_imask();
215
216 /* taskYIELD() can only be called from a task, not an interrupt, so the
217 current interrupt mask can only be 0 or portKERNEL_INTERRUPT_PRIORITY and
218 the mask can be set without risk of accidentally lowering the mask value. */
219 set_imask( portKERNEL_INTERRUPT_PRIORITY );
220
221 trapa( portYIELD_TRAP_NO );
222
223 /* Restore the interrupt mask to whatever it was previously (when the
224 function was entered). */
225 set_imask( ( int ) lInterruptMask );
226 }
227 /*-----------------------------------------------------------*/
228
xPortUsesFloatingPoint(TaskHandle_t xTask)229 BaseType_t xPortUsesFloatingPoint( TaskHandle_t xTask )
230 {
231 uint32_t *pulFlopBuffer;
232 BaseType_t xReturn;
233 extern void * volatile pxCurrentTCB;
234
235 /* This function tells the kernel that the task referenced by xTask is
236 going to use the floating point registers and therefore requires the
237 floating point registers saved as part of its context. */
238
239 /* Passing NULL as xTask is used to indicate that the calling task is the
240 subject task - so pxCurrentTCB is the task handle. */
241 if( xTask == NULL )
242 {
243 xTask = ( TaskHandle_t ) pxCurrentTCB;
244 }
245
246 /* Allocate a buffer large enough to hold all the flop registers. */
247 pulFlopBuffer = ( uint32_t * ) pvPortMalloc( portFLOP_STORAGE_SIZE );
248
249 if( pulFlopBuffer != NULL )
250 {
251 /* Start with the registers in a benign state. */
252 memset( ( void * ) pulFlopBuffer, 0x00, portFLOP_STORAGE_SIZE );
253
254 /* The first thing to get saved in the buffer is the FPSCR value -
255 initialise this to the current FPSCR value. */
256 *pulFlopBuffer = get_fpscr();
257
258 /* Use the task tag to point to the flop buffer. Pass pointer to just
259 above the buffer because the flop save routine uses a pre-decrement. */
260 vTaskSetApplicationTaskTag( xTask, ( void * ) ( pulFlopBuffer + portFLOP_REGISTERS_TO_STORE ) );
261 xReturn = pdPASS;
262 }
263 else
264 {
265 xReturn = pdFAIL;
266 }
267
268 return xReturn;
269 }
270 /*-----------------------------------------------------------*/
271
