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, TaskFunction_t pxCode, void *pvParameters )
74 {
75 uint16_t *pusTopOfStack;
76 uint32_t *pulTopOfStack, ulTemp;
77 
78     /*
79         Place a few bytes of known values on the bottom of the stack.
80         This is just useful for debugging and can be included if required.
81 
82         *pxTopOfStack = ( StackType_t ) 0x1111;
83         pxTopOfStack--;
84         *pxTopOfStack = ( StackType_t ) 0x2222;
85         pxTopOfStack--;
86         *pxTopOfStack = ( StackType_t ) 0x3333;
87         pxTopOfStack--;
88     */
89 
90     /* Data types are need either 16 bits or 32 bits depending on the data
91     and code model used. */
92     if( sizeof( pxCode ) == sizeof( uint16_t ) )
93     {
94         pusTopOfStack = ( uint16_t * ) pxTopOfStack;
95         ulTemp = ( uint32_t ) pxCode;
96         *pusTopOfStack = ( uint16_t ) ulTemp;
97     }
98     else
99     {
100         /* Make room for a 20 bit value stored as a 32 bit value. */
101         pusTopOfStack = ( uint16_t * ) pxTopOfStack;
102         pusTopOfStack--;
103         pulTopOfStack = ( uint32_t * ) pusTopOfStack;
104         *pulTopOfStack = ( uint32_t ) pxCode;
105     }
106 
107     pusTopOfStack--;
108     *pusTopOfStack = portFLAGS_INT_ENABLED;
109     pusTopOfStack -= ( sizeof( StackType_t ) / 2 );
110 
111     /* From here on the size of stacked items depends on the memory model. */
112     pxTopOfStack = ( StackType_t * ) pusTopOfStack;
113 
114     /* Next the general purpose registers. */
115     #ifdef PRELOAD_REGISTER_VALUES
116         *pxTopOfStack = ( StackType_t ) 0xffff;
117         pxTopOfStack--;
118         *pxTopOfStack = ( StackType_t ) 0xeeee;
119         pxTopOfStack--;
120         *pxTopOfStack = ( StackType_t ) 0xdddd;
121         pxTopOfStack--;
122         *pxTopOfStack = ( StackType_t ) pvParameters;
123         pxTopOfStack--;
124         *pxTopOfStack = ( StackType_t ) 0xbbbb;
125         pxTopOfStack--;
126         *pxTopOfStack = ( StackType_t ) 0xaaaa;
127         pxTopOfStack--;
128         *pxTopOfStack = ( StackType_t ) 0x9999;
129         pxTopOfStack--;
130         *pxTopOfStack = ( StackType_t ) 0x8888;
131         pxTopOfStack--;
132         *pxTopOfStack = ( StackType_t ) 0x5555;
133         pxTopOfStack--;
134         *pxTopOfStack = ( StackType_t ) 0x6666;
135         pxTopOfStack--;
136         *pxTopOfStack = ( StackType_t ) 0x5555;
137         pxTopOfStack--;
138         *pxTopOfStack = ( StackType_t ) 0x4444;
139         pxTopOfStack--;
140     #else
141         pxTopOfStack -= 3;
142         *pxTopOfStack = ( StackType_t ) pvParameters;
143         pxTopOfStack -= 9;
144     #endif
145 
146     /* A variable is used to keep track of the critical section nesting.
147     This variable has to be stored as part of the task context and is
148     initially set to zero. */
149     *pxTopOfStack = ( StackType_t ) portNO_CRITICAL_SECTION_NESTING;
150 
151     /* Return a pointer to the top of the stack we have generated so this can
152     be stored in the task control block for the task. */
153     return pxTopOfStack;
154 }
155 /*-----------------------------------------------------------*/
156 
vPortEndScheduler(void)157 void vPortEndScheduler( void )
158 {
159     /* It is unlikely that the MSP430 port will get stopped.  If required simply
160     disable the tick interrupt here. */
161 }
162 /*-----------------------------------------------------------*/
163 
164 /*
165  * Hardware initialisation to generate the RTOS tick.
166  */
vPortSetupTimerInterrupt(void)167 void vPortSetupTimerInterrupt( void )
168 {
169     vApplicationSetupTimerInterrupt();
170 }
171 /*-----------------------------------------------------------*/
172 
173 #pragma vector=configTICK_VECTOR
vTickISREntry(void)174 interrupt void vTickISREntry( void )
175 {
176 extern void vPortTickISR( void );
177 
178     __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
179     #if configUSE_PREEMPTION == 1
180         extern void vPortPreemptiveTickISR( void );
181         vPortPreemptiveTickISR();
182     #else
183         extern void vPortCooperativeTickISR( void );
184         vPortCooperativeTickISR();
185     #endif
186 }
187 
188 
189