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25 This file is part of the FreeRTOS distribution.
27 FreeRTOS is free software; you can redistribute it and/or modify it under
28 the terms of the GNU General Public License (version 2) as published by the
29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
30 ***NOTE*** The exception to the GPL is included to allow you to distribute
31 a combined work that includes FreeRTOS without being obliged to provide the
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54 /* Standard includes. */
57 /* Kernel includes. */
61 /* Machine includes */
62 #include <machine/counter.h>
63 #include <machine/ic.h>
64 /*-----------------------------------------------------------*/
66 /* The initial PSR has the Previous Interrupt Enabled (PIEN) flag set. */
67 #define portINITIAL_PSR ( 0x00020000 )
69 /*-----------------------------------------------------------*/
72 * Perform any hardware configuration necessary to generate the tick interrupt.
74 static void prvSetupTickInterrupt( void );
75 /*-----------------------------------------------------------*/
77 /* Variables used to hold interrupt and critical nesting depths, with variables
78 that provide a convenient method of obtaining their addresses. */
79 volatile unsigned portBASE_TYPE uxInterruptNestingCount = 999UL;
80 const volatile unsigned portBASE_TYPE *puxInterruptNestingCount = &uxInterruptNestingCount;
81 volatile unsigned portBASE_TYPE uxInterruptStack[ configMINIMAL_STACK_SIZE ];
82 const volatile unsigned portBASE_TYPE *puxTopOfInterruptStack = &( uxInterruptStack[ configMINIMAL_STACK_SIZE - 1 ] );
83 /*-----------------------------------------------------------*/
85 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE * pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
87 /* For the time being, mimic the stack when using the
88 __attribute__((interrupt)) plus the extra caller saved registers. */
92 pxTopOfStack[ 16 ] = ( portSTACK_TYPE )pxCode;
95 pxTopOfStack[ 15 ] = portINITIAL_PSR;
97 /* R14 and R15 aka FuncSP and LR, respectively */
98 pxTopOfStack[ 14 ] = 0x00000000;
99 pxTopOfStack[ 13 ] = ( portSTACK_TYPE )( pxTopOfStack + 17 );
102 pxTopOfStack[ 12 ] = 0x07070707;
103 pxTopOfStack[ 11 ] = 0x06060606;
104 pxTopOfStack[ 10 ] = 0x05050505;
105 pxTopOfStack[ 9 ] = 0x04040404;
106 pxTopOfStack[ 8 ] = 0x03030303;
107 pxTopOfStack[ 7 ] = ( portSTACK_TYPE )pvParameters;
109 /* Set the Interrupt Priority on Task entry. */
110 pxTopOfStack[ 6 ] = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
113 pxTopOfStack[ 5 ] = 0x0D0D0D0D;
114 pxTopOfStack[ 4 ] = 0x0C0C0C0C;
115 pxTopOfStack[ 3 ] = 0x0B0B0B0B;
116 pxTopOfStack[ 2 ] = 0x0A0A0A0A;
117 pxTopOfStack[ 1 ] = 0x09090909;
118 pxTopOfStack[ 0 ] = 0x08080808;
122 /*-----------------------------------------------------------*/
124 portBASE_TYPE xPortStartScheduler( void )
126 /* Set-up the Tick Interrupt. */
127 prvSetupTickInterrupt();
129 /* Enable the TRAP yield. */
130 irq[ portIRQ_TRAP_YIELD ].ien = 1;
131 irq[ portIRQ_TRAP_YIELD ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
133 /* Integrated Interrupt Controller: Enable all interrupts. */
135 uxInterruptNestingCount = 1UL;
137 /* Restore calleree saved registers. */
138 portRESTORE_CONTEXT_REDUCED();
140 /* Mimic an ISR epiplogue to start the task executing. */
143 "ldd r6, [r1]+0x20 \n" \
146 "ldd r14, [r1]+0x18 \n" \
147 "ldq r4, [r1]+0x8 \n" \
153 /* Should not get here. */
156 /*-----------------------------------------------------------*/
158 static void prvSetupTickInterrupt( void )
160 /* Enable timer interrupts */
161 counter1->reload = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1;
162 counter1->value = counter1->reload;
165 /* Set the IRQ Handler priority and enable it. */
166 irq[ IRQ_COUNTER1 ].ien = 1;
167 irq[ IRQ_COUNTER1 ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
169 /*-----------------------------------------------------------*/
171 void interrupt_handler( portIRQ_TRAP_YIELD )
173 /* Save remaining registers. */
174 portSAVE_CONTEXT_REDUCED();
176 /* Perform the actual Yield. */
177 portYIELD_FROM_ISR();
179 /* Restore the first lot of registers, the remains will be resotred when
180 this function exits. */
181 portRESTORE_CONTEXT_REDUCED();
183 /*-----------------------------------------------------------*/
185 /* Timer tick interrupt handler */
186 void interrupt_handler( IRQ_COUNTER1 )
188 portSAVE_CONTEXT_REDUCED();
191 " sub r1, #4 \n" /* Make space on the stack. r1 is stack pointer. */
192 " movhi r2, #16384 \n" /* Load the pointer to the IC. */
193 " ldub r3, [r2]+2 \n" /* Copy the Current Priority Level. */
194 " st r3, [r1] \n" /* Store it on the stack. */
195 " mov r3, #%0 \n" /* Load the highest priority level. */
196 " stb r3, [r2]+2 \n" /* Set the CPL to the highest level. */
197 " call vTaskIncrementTick \n" /* Increment the tick. */
198 " ld r3, [r1] \n" /* Load the previous CPL from the stack. */
199 " movhi r2, #16384 \n" /* Load the pointer to the IC. */
200 " stb r3, [r2]+2 \n" /* Set the CPL to the previous CPL. */
203 :"i"( portSYSTEM_INTERRUPT_PRIORITY_LEVEL + 1 )
204 :"r2","r3" /* Fix the stack. */
207 #if configUSE_PREEMPTION == 1
208 portYIELD_FROM_ISR();
212 /* Clear the Tick Interrupt. */
213 counter1->expired = 0;
216 portRESTORE_CONTEXT_REDUCED();
218 /*-----------------------------------------------------------*/
220 void vPortEndScheduler( void )
222 /* Nothing to do. Unlikely to want to end. */
224 /*-----------------------------------------------------------*/