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 /* Kernel includes. */
30 #include "FreeRTOS.h"
31 #include "task.h"
32
33
34 #define portINITIAL_FORMAT_VECTOR ( ( StackType_t ) 0x4000 )
35
36 /* Supervisor mode set. */
37 #define portINITIAL_STATUS_REGISTER ( ( StackType_t ) 0x2000)
38
39 /* The clock prescale into the timer peripheral. */
40 #define portPRESCALE_VALUE ( ( uint8_t ) 10 )
41
42 /* The clock frequency into the RTC. */
43 #define portRTC_CLOCK_HZ ( ( uint32_t ) 1000 )
44
45 asm void interrupt VectorNumber_VL1swi vPortYieldISR( void );
46 static void prvSetupTimerInterrupt( void );
47
48 /* Used to keep track of the number of nested calls to taskENTER_CRITICAL(). This
49 will be set to 0 prior to the first task being started. */
50 static uint32_t ulCriticalNesting = 0x9999UL;
51
52 /*-----------------------------------------------------------*/
53
pxPortInitialiseStack(StackType_t * pxTopOfStack,TaskFunction_t pxCode,void * pvParameters)54 StackType_t *pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
55 {
56
57 uint32_t ulOriginalA5;
58
59 __asm{ MOVE.L A5, ulOriginalA5 };
60
61
62 *pxTopOfStack = (StackType_t) 0xDEADBEEF;
63 pxTopOfStack--;
64
65 /* Exception stack frame starts with the return address. */
66 *pxTopOfStack = ( StackType_t ) pxCode;
67 pxTopOfStack--;
68
69 *pxTopOfStack = ( portINITIAL_FORMAT_VECTOR << 16UL ) | ( portINITIAL_STATUS_REGISTER );
70 pxTopOfStack--;
71
72 *pxTopOfStack = ( StackType_t ) 0x0; /*FP*/
73 pxTopOfStack -= 14; /* A5 to D0. */
74
75 /* Parameter in A0. */
76 *( pxTopOfStack + 8 ) = ( StackType_t ) pvParameters;
77
78 /* A5 must be maintained as it is reserved by the compiler. */
79 *( pxTopOfStack + 13 ) = ulOriginalA5;
80
81 return pxTopOfStack;
82 }
83 /*-----------------------------------------------------------*/
84
xPortStartScheduler(void)85 BaseType_t xPortStartScheduler( void )
86 {
87 extern void vPortStartFirstTask( void );
88
89 ulCriticalNesting = 0UL;
90
91 /* Configure a timer to generate the tick interrupt. */
92 prvSetupTimerInterrupt();
93
94 /* Start the first task executing. */
95 vPortStartFirstTask();
96
97 return pdFALSE;
98 }
99 /*-----------------------------------------------------------*/
100
prvSetupTimerInterrupt(void)101 static void prvSetupTimerInterrupt( void )
102 {
103 /* Prescale by 1 - ie no prescale. */
104 RTCSC |= 8;
105
106 /* Compare match value. */
107 RTCMOD = portRTC_CLOCK_HZ / configTICK_RATE_HZ;
108
109 /* Enable the RTC to generate interrupts - interrupts are already disabled
110 when this code executes. */
111 RTCSC_RTIE = 1;
112 }
113 /*-----------------------------------------------------------*/
114
vPortEndScheduler(void)115 void vPortEndScheduler( void )
116 {
117 /* Not implemented as there is nothing to return to. */
118 }
119 /*-----------------------------------------------------------*/
120
vPortEnterCritical(void)121 void vPortEnterCritical( void )
122 {
123 if( ulCriticalNesting == 0UL )
124 {
125 /* Guard against context switches being pended simultaneously with a
126 critical section being entered. */
127 do
128 {
129 portDISABLE_INTERRUPTS();
130 if( INTC_FRC == 0UL )
131 {
132 break;
133 }
134
135 portENABLE_INTERRUPTS();
136
137 } while( 1 );
138 }
139 ulCriticalNesting++;
140 }
141 /*-----------------------------------------------------------*/
142
vPortExitCritical(void)143 void vPortExitCritical( void )
144 {
145 ulCriticalNesting--;
146 if( ulCriticalNesting == 0 )
147 {
148 portENABLE_INTERRUPTS();
149 }
150 }
151 /*-----------------------------------------------------------*/
152
vPortYieldHandler(void)153 void vPortYieldHandler( void )
154 {
155 uint32_t ulSavedInterruptMask;
156
157 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
158 {
159 /* Note this will clear all forced interrupts - this is done for speed. */
160 INTC_CFRC = 0x3E;
161 vTaskSwitchContext();
162 }
163 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
164 }
165 /*-----------------------------------------------------------*/
166
vPortTickISR(void)167 void interrupt VectorNumber_Vrtc vPortTickISR( void )
168 {
169 uint32_t ulSavedInterruptMask;
170
171 /* Clear the interrupt. */
172 RTCSC |= RTCSC_RTIF_MASK;
173
174 /* Increment the RTOS tick. */
175 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
176 {
177 if( xTaskIncrementTick() != pdFALSE )
178 {
179 taskYIELD();
180 }
181 }
182 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
183 }
184
