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 /* Scheduler includes. */
30 #include "FreeRTOS.h"
31 #include "task.h"
32
33 /*-----------------------------------------------------------
34 * Implementation of functions defined in portable.h for the MSP430X port.
35 *----------------------------------------------------------*/
36
37 /* Constants required for hardware setup. The tick ISR runs off the ACLK,
38 * not the MCLK. */
39 #define portACLK_FREQUENCY_HZ ( ( TickType_t ) 32768 )
40 #define portINITIAL_CRITICAL_NESTING ( ( uint16_t ) 10 )
41 #define portFLAGS_INT_ENABLED ( ( StackType_t ) 0x08 )
42
43 /* We require the address of the pxCurrentTCB variable, but don't want to know
44 * any details of its type. */
45 typedef void TCB_t;
46 extern volatile TCB_t * volatile pxCurrentTCB;
47
48 /* Each task maintains a count of the critical section nesting depth. Each
49 * time a critical section is entered the count is incremented. Each time a
50 * critical section is exited the count is decremented - with interrupts only
51 * being re-enabled if the count is zero.
52 *
53 * usCriticalNesting will get set to zero when the scheduler starts, but must
54 * not be initialised to zero as this will cause problems during the startup
55 * sequence. */
56 volatile uint16_t usCriticalNesting = portINITIAL_CRITICAL_NESTING;
57 /*-----------------------------------------------------------*/
58
59
60 /*
61 * Sets up the periodic ISR used for the RTOS tick. This uses timer 0, but
62 * could have alternatively used the watchdog timer or timer 1.
63 */
64 void vPortSetupTimerInterrupt( void );
65 /*-----------------------------------------------------------*/
66
67 /*
68 * Initialise the stack of a task to look exactly as if a call to
69 * portSAVE_CONTEXT had been called.
70 *
71 * See the header file portable.h.
72 */
pxPortInitialiseStack(StackType_t * pxTopOfStack,TaskFunction_t pxCode,void * pvParameters)73 StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
74 TaskFunction_t pxCode,
75 void * pvParameters )
76 {
77 uint16_t * pusTopOfStack;
78 uint32_t * pulTopOfStack;
79
80 /*
81 * Place a few bytes of known values on the bottom of the stack.
82 * This is just useful for debugging and can be included if required.
83 *
84 * pxTopOfStack = ( StackType_t ) 0x1111;
85 * pxTopOfStack--;
86 * pxTopOfStack = ( StackType_t ) 0x2222;
87 * pxTopOfStack--;
88 * pxTopOfStack = ( StackType_t ) 0x3333;
89 */
90
91 /* StackType_t is either 16 bits or 32 bits depending on the data model.
92 * Some stacked items do not change size depending on the data model so have
93 * to be explicitly cast to the correct size so this function will work
94 * whichever data model is being used. */
95 if( sizeof( StackType_t ) == sizeof( uint16_t ) )
96 {
97 /* Make room for a 20 bit value stored as a 32 bit value. */
98 pusTopOfStack = ( uint16_t * ) pxTopOfStack;
99 pusTopOfStack--;
100 pulTopOfStack = ( uint32_t * ) pusTopOfStack;
101 }
102 else
103 {
104 pulTopOfStack = ( uint32_t * ) pxTopOfStack;
105 }
106
107 *pulTopOfStack = ( uint32_t ) pxCode;
108
109 pusTopOfStack = ( uint16_t * ) pulTopOfStack;
110 pusTopOfStack--;
111 *pusTopOfStack = portFLAGS_INT_ENABLED;
112 pusTopOfStack -= ( sizeof( StackType_t ) / 2 );
113
114 /* From here on the size of stacked items depends on the memory model. */
115 pxTopOfStack = ( StackType_t * ) pusTopOfStack;
116
117 /* Next the general purpose registers. */
118 #ifdef PRELOAD_REGISTER_VALUES
119 *pxTopOfStack = ( StackType_t ) 0xffff;
120 pxTopOfStack--;
121 *pxTopOfStack = ( StackType_t ) 0xeeee;
122 pxTopOfStack--;
123 *pxTopOfStack = ( StackType_t ) 0xdddd;
124 pxTopOfStack--;
125 *pxTopOfStack = ( StackType_t ) pvParameters;
126 pxTopOfStack--;
127 *pxTopOfStack = ( StackType_t ) 0xbbbb;
128 pxTopOfStack--;
129 *pxTopOfStack = ( StackType_t ) 0xaaaa;
130 pxTopOfStack--;
131 *pxTopOfStack = ( StackType_t ) 0x9999;
132 pxTopOfStack--;
133 *pxTopOfStack = ( StackType_t ) 0x8888;
134 pxTopOfStack--;
135 *pxTopOfStack = ( StackType_t ) 0x5555;
136 pxTopOfStack--;
137 *pxTopOfStack = ( StackType_t ) 0x6666;
138 pxTopOfStack--;
139 *pxTopOfStack = ( StackType_t ) 0x5555;
140 pxTopOfStack--;
141 *pxTopOfStack = ( StackType_t ) 0x4444;
142 pxTopOfStack--;
143 #else /* ifdef PRELOAD_REGISTER_VALUES */
144 pxTopOfStack -= 3;
145 *pxTopOfStack = ( StackType_t ) pvParameters;
146 pxTopOfStack -= 9;
147 #endif /* ifdef PRELOAD_REGISTER_VALUES */
148
149
150 /* A variable is used to keep track of the critical section nesting.
151 * This variable has to be stored as part of the task context and is
152 * initially set to zero. */
153 *pxTopOfStack = ( StackType_t ) portNO_CRITICAL_SECTION_NESTING;
154
155 /* Return a pointer to the top of the stack we have generated so this can
156 * be stored in the task control block for the task. */
157 return pxTopOfStack;
158 }
159 /*-----------------------------------------------------------*/
160
vPortEndScheduler(void)161 void vPortEndScheduler( void )
162 {
163 /* It is unlikely that the MSP430 port will get stopped. If required simply
164 * disable the tick interrupt here. */
165 }
166 /*-----------------------------------------------------------*/
167
168 /*
169 * Hardware initialisation to generate the RTOS tick.
170 */
vPortSetupTimerInterrupt(void)171 void vPortSetupTimerInterrupt( void )
172 {
173 vApplicationSetupTimerInterrupt();
174 }
175 /*-----------------------------------------------------------*/
176
177 #pragma vector=configTICK_VECTOR
vTickISREntry(void)178 __interrupt __raw void vTickISREntry( void )
179 {
180 extern void vPortTickISR( void );
181
182 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
183 vPortTickISR();
184 }
185
