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Diffstat (limited to 'libraries/FreeRTOS/utility/port.c')
| -rwxr-xr-x | libraries/FreeRTOS/utility/port.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/libraries/FreeRTOS/utility/port.c b/libraries/FreeRTOS/utility/port.c new file mode 100755 index 0000000..dc01720 --- /dev/null +++ b/libraries/FreeRTOS/utility/port.c @@ -0,0 +1,292 @@ +/* + FreeRTOS V7.0.1 - Copyright (C) 2011 Real Time Engineers Ltd. + + + *************************************************************************** + * * + * FreeRTOS tutorial books are available in pdf and paperback. * + * Complete, revised, and edited pdf reference manuals are also * + * available. * + * * + * Purchasing FreeRTOS documentation will not only help you, by * + * ensuring you get running as quickly as possible and with an * + * in-depth knowledge of how to use FreeRTOS, it will also help * + * the FreeRTOS project to continue with its mission of providing * + * professional grade, cross platform, de facto standard solutions * + * for microcontrollers - completely free of charge! * + * * + * >>> See http://www.FreeRTOS.org/Documentation for details. <<< * + * * + * Thank you for using FreeRTOS, and thank you for your support! * + * * + *************************************************************************** + + + This file is part of the FreeRTOS distribution. + + FreeRTOS is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License (version 2) as published by the + Free Software Foundation AND MODIFIED BY the FreeRTOS exception. + >>>NOTE<<< The modification to the GPL is included to allow you to + distribute a combined work that includes FreeRTOS without being obliged to + provide the source code for proprietary components outside of the FreeRTOS + kernel. FreeRTOS is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + more details. You should have received a copy of the GNU General Public + License and the FreeRTOS license exception along with FreeRTOS; if not it + can be viewed here: http://www.freertos.org/a00114.html and also obtained + by writing to Richard Barry, contact details for whom are available on the + FreeRTOS WEB site. + + 1 tab == 4 spaces! + + http://www.FreeRTOS.org - Documentation, latest information, license and + contact details. + + http://www.SafeRTOS.com - A version that is certified for use in safety + critical systems. + + http://www.OpenRTOS.com - Commercial support, development, porting, + licensing and training services. +*/ + +/*----------------------------------------------------------- + * Implementation of functions defined in portable.h for the ARM CM3 port. + *----------------------------------------------------------*/ + +/* Scheduler includes. */ +#include "FreeRTOS.h" +#include "task.h" + +/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is +defined. The value should also ensure backward compatibility. +FreeRTOS.org versions prior to V4.4.0 did not include this definition. */ +#ifndef configKERNEL_INTERRUPT_PRIORITY + #define configKERNEL_INTERRUPT_PRIORITY 255 +#endif + +/* Constants required to manipulate the NVIC. */ +#define portNVIC_SYSTICK_CTRL ( ( volatile unsigned long *) 0xe000e010 ) +#define portNVIC_SYSTICK_LOAD ( ( volatile unsigned long *) 0xe000e014 ) +#define portNVIC_INT_CTRL ( ( volatile unsigned long *) 0xe000ed04 ) +#define portNVIC_SYSPRI2 ( ( volatile unsigned long *) 0xe000ed20 ) +#define portNVIC_SYSTICK_CLK 0x00000004 +#define portNVIC_SYSTICK_INT 0x00000002 +#define portNVIC_SYSTICK_ENABLE 0x00000001 +#define portNVIC_PENDSVSET 0x10000000 +#define portNVIC_PENDSV_PRI ( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 16 ) +#define portNVIC_SYSTICK_PRI ( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 24 ) + +/* Constants required to set up the initial stack. */ +#define portINITIAL_XPSR ( 0x01000000 ) + +/* The priority used by the kernel is assigned to a variable to make access +from inline assembler easier. */ +const unsigned long ulKernelPriority = configKERNEL_INTERRUPT_PRIORITY; + +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa; + +/* + * Setup the timer to generate the tick interrupts. + */ +static void prvSetupTimerInterrupt( void ); + +/* + * Exception handlers. + */ +void xPortPendSVHandler( void ) __attribute__ (( naked )); +void xPortSysTickHandler( void ); +void vPortSVCHandler( void ) __attribute__ (( naked )); + +/* + * Start first task is a separate function so it can be tested in isolation. + */ +void vPortStartFirstTask( void ) __attribute__ (( naked )); + +/*-----------------------------------------------------------*/ + +/* + * See header file for description. + */ +portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) +{ + /* Simulate the stack frame as it would be created by a context switch + interrupt. */ + pxTopOfStack--; /* Offset added to account for the way the MCU uses the stack on entry/exit of interrupts. */ + *pxTopOfStack = portINITIAL_XPSR; /* xPSR */ + pxTopOfStack--; + *pxTopOfStack = ( portSTACK_TYPE ) pxCode; /* PC */ + pxTopOfStack--; + *pxTopOfStack = 0; /* LR */ + pxTopOfStack -= 5; /* R12, R3, R2 and R1. */ + *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */ + pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */ + + return pxTopOfStack; +} +/*-----------------------------------------------------------*/ + +// !!! Maple +// void vPortSVCHandler( void ) +void __exc_svc( void ) +// !!! Maple +{ + __asm volatile ( + " ldr r3, pxCurrentTCBConst2 \n" /* Restore the context. */ + " ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */ + " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */ + " ldmia r0!, {r4-r11} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */ + " msr psp, r0 \n" /* Restore the task stack pointer. */ + " mov r0, #0 \n" + " msr basepri, r0 \n" + " orr r14, #0xd \n" + " bx r14 \n" + " \n" + " .align 2 \n" + "pxCurrentTCBConst2: .word pxCurrentTCB \n" + ); +} +/*-----------------------------------------------------------*/ + +void vPortStartFirstTask( void ) +{ + __asm volatile( + " ldr r0, =0xE000ED08 \n" /* Use the NVIC offset register to locate the stack. */ + " ldr r0, [r0] \n" + " ldr r0, [r0] \n" + " msr msp, r0 \n" /* Set the msp back to the start of the stack. */ + " cpsie i \n" /* Globally enable interrupts. */ + " svc 0 \n" /* System call to start first task. */ + " nop \n" + ); +} +/*-----------------------------------------------------------*/ + +/* + * See header file for description. + */ +portBASE_TYPE xPortStartScheduler( void ) +{ + /* Make PendSV, CallSV and SysTick the same priroity as the kernel. */ + *(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI; + *(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI; + +// !!! Maple + systick_attach_callback(&xPortSysTickHandler); +// /* Start the timer that generates the tick ISR. Interrupts are disabled +// here already. */ +// prvSetupTimerInterrupt(); +// !!! Maple + + /* Initialise the critical nesting count ready for the first task. */ + uxCriticalNesting = 0; + + /* Start the first task. */ + vPortStartFirstTask(); + + /* Should not get here! */ + return 0; +} +/*-----------------------------------------------------------*/ + +void vPortEndScheduler( void ) +{ + /* It is unlikely that the CM3 port will require this function as there + is nothing to return to. */ +} +/*-----------------------------------------------------------*/ + +void vPortYieldFromISR( void ) +{ + /* Set a PendSV to request a context switch. */ + *(portNVIC_INT_CTRL) = portNVIC_PENDSVSET; +} +/*-----------------------------------------------------------*/ + +void vPortEnterCritical( void ) +{ + portDISABLE_INTERRUPTS(); + uxCriticalNesting++; +} +/*-----------------------------------------------------------*/ + +void vPortExitCritical( void ) +{ + uxCriticalNesting--; + if( uxCriticalNesting == 0 ) + { + portENABLE_INTERRUPTS(); + } +} +/*-----------------------------------------------------------*/ + +// !!! Maple +// void xPortPendSVHandler( void ) +void __exc_pendsv( void ) +// !!! Maple +{ + /* This is a naked function. */ + + __asm volatile + ( + " mrs r0, psp \n" + " \n" + " ldr r3, pxCurrentTCBConst \n" /* Get the location of the current TCB. */ + " ldr r2, [r3] \n" + " \n" + " stmdb r0!, {r4-r11} \n" /* Save the remaining registers. */ + " str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */ + " \n" + " stmdb sp!, {r3, r14} \n" + " mov r0, %0 \n" + " msr basepri, r0 \n" + " bl vTaskSwitchContext \n" + " mov r0, #0 \n" + " msr basepri, r0 \n" + " ldmia sp!, {r3, r14} \n" + " \n" /* Restore the context, including the critical nesting count. */ + " ldr r1, [r3] \n" + " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */ + " ldmia r0!, {r4-r11} \n" /* Pop the registers. */ + " msr psp, r0 \n" + " bx r14 \n" + " \n" + " .align 2 \n" + "pxCurrentTCBConst: .word pxCurrentTCB \n" + ::"i"(configMAX_SYSCALL_INTERRUPT_PRIORITY) + ); +} +/*-----------------------------------------------------------*/ + +void xPortSysTickHandler( void ) +{ +unsigned long ulDummy; + + /* If using preemption, also force a context switch. */ + #if configUSE_PREEMPTION == 1 + *(portNVIC_INT_CTRL) = portNVIC_PENDSVSET; + #endif + + ulDummy = portSET_INTERRUPT_MASK_FROM_ISR(); + { + vTaskIncrementTick(); + } + portCLEAR_INTERRUPT_MASK_FROM_ISR( ulDummy ); +} +/*-----------------------------------------------------------*/ + +/* + * Setup the systick timer to generate the tick interrupts at the required + * frequency. + */ +void prvSetupTimerInterrupt( void ) +{ + /* Configure SysTick to interrupt at the requested rate. */ + *(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL; + *(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE; +} +/*-----------------------------------------------------------*/ + |