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/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the RX600 port.
*----------------------------------------------------------*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
/* Library includes. */
#include "string.h"
/* Hardware specifics. */
#include "iodefine.h"
/*-----------------------------------------------------------*/
/* Tasks should start with interrupts enabled and in Supervisor mode, therefore
* PSW is set with U and I set, and PM and IPL clear. */
#define portINITIAL_PSW ( ( StackType_t ) 0x00030000 )
#define portINITIAL_FPSW ( ( StackType_t ) 0x00000100 )
/*-----------------------------------------------------------*/
/* The following lines are to ensure vSoftwareInterruptEntry can be referenced,
* and therefore installed in the vector table, when the FreeRTOS code is built
* as a library. */
extern BaseType_t vSoftwareInterruptEntry;
const BaseType_t * p_vSoftwareInterruptEntry = &vSoftwareInterruptEntry;
/*-----------------------------------------------------------*/
/*
* Function to start the first task executing - written in asm code as direct
* access to registers is required.
*/
static void prvStartFirstTask( void );
/*
* Software interrupt handler. Performs the actual context switch (saving and
* restoring of registers). Written in asm code as direct register access is
* required.
*/
static void prvYieldHandler( void );
/*
* The entry point for the software interrupt handler. This is the function
* that calls the inline asm function prvYieldHandler(). It is installed in
* the vector table, but the code that installs it is in prvYieldHandler rather
* than using a #pragma.
*/
void vSoftwareInterruptISR( void );
/*-----------------------------------------------------------*/
/* This is accessed by the inline assembler functions so is file scope for
* convenience. */
extern void * pxCurrentTCB;
extern void vTaskSwitchContext( void );
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
TaskFunction_t pxCode,
void * pvParameters )
{
/* R0 is not included as it is the stack pointer. */
*pxTopOfStack = 0x00;
pxTopOfStack--;
*pxTopOfStack = portINITIAL_PSW;
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) pxCode;
/* When debugging it can be useful if every register is set to a known
* value. Otherwise code space can be saved by just setting the registers
* that need to be set. */
#ifdef USE_FULL_REGISTER_INITIALISATION
{
pxTopOfStack--;
*pxTopOfStack = 0xffffffff; /* r15. */
pxTopOfStack--;
*pxTopOfStack = 0xeeeeeeee;
pxTopOfStack--;
*pxTopOfStack = 0xdddddddd;
pxTopOfStack--;
*pxTopOfStack = 0xcccccccc;
pxTopOfStack--;
*pxTopOfStack = 0xbbbbbbbb;
pxTopOfStack--;
*pxTopOfStack = 0xaaaaaaaa;
pxTopOfStack--;
*pxTopOfStack = 0x99999999;
pxTopOfStack--;
*pxTopOfStack = 0x88888888;
pxTopOfStack--;
*pxTopOfStack = 0x77777777;
pxTopOfStack--;
*pxTopOfStack = 0x66666666;
pxTopOfStack--;
*pxTopOfStack = 0x55555555;
pxTopOfStack--;
*pxTopOfStack = 0x44444444;
pxTopOfStack--;
*pxTopOfStack = 0x33333333;
pxTopOfStack--;
*pxTopOfStack = 0x22222222;
pxTopOfStack--;
}
#else /* ifdef USE_FULL_REGISTER_INITIALISATION */
{
pxTopOfStack -= 15;
}
#endif /* ifdef USE_FULL_REGISTER_INITIALISATION */
*pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
pxTopOfStack--;
*pxTopOfStack = portINITIAL_FPSW;
pxTopOfStack--;
*pxTopOfStack = 0x12345678; /* Accumulator. */
pxTopOfStack--;
*pxTopOfStack = 0x87654321; /* Accumulator. */
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
BaseType_t xPortStartScheduler( void )
{
extern void vApplicationSetupTimerInterrupt( void );
/* Use pxCurrentTCB just so it does not get optimised away. */
if( pxCurrentTCB != NULL )
{
/* Call an application function to set up the timer that will generate the
* tick interrupt. This way the application can decide which peripheral to
* use. A demo application is provided to show a suitable example. */
vApplicationSetupTimerInterrupt();
/* Enable the software interrupt. */
_IEN( _ICU_SWINT ) = 1;
/* Ensure the software interrupt is clear. */
_IR( _ICU_SWINT ) = 0;
/* Ensure the software interrupt is set to the kernel priority. */
_IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
/* Start the first task. */
prvStartFirstTask();
}
/* Just to make sure the function is not optimised away. */
( void ) vSoftwareInterruptISR();
/* Should not get here. */
return pdFAIL;
}
/*-----------------------------------------------------------*/
#pragma inline_asm prvStartFirstTask
static void prvStartFirstTask( void )
{
/* When starting the scheduler there is nothing that needs moving to the
* interrupt stack because the function is not called from an interrupt.
* Just ensure the current stack is the user stack. */
SETPSW U
/* Obtain the location of the stack associated with which ever task
* pxCurrentTCB is currently pointing to. */
MOV.L # _pxCurrentTCB, R15
MOV.L[ R15 ], R15
MOV.L[ R15 ], R0
/* Restore the registers from the stack of the task pointed to by
* pxCurrentTCB. */
POP R15
MVTACLO R15 /* Accumulator low 32 bits. */
POP R15
MVTACHI R15 /* Accumulator high 32 bits. */
POP R15
MVTC R15, FPSW /* Floating point status word. */
POPM R1 - R15 /* R1 to R15 - R0 is not included as it is the SP. */
RTE /* This pops the remaining registers. */
NOP
NOP
}
/*-----------------------------------------------------------*/
#pragma interrupt ( vTickISR( vect = _VECT( configTICK_VECTOR ), enable ) )
void vTickISR( void )
{
/* Increment the tick, and perform any processing the new tick value
* necessitates. */
set_ipl( configMAX_SYSCALL_INTERRUPT_PRIORITY );
{
if( xTaskIncrementTick() != pdFALSE )
{
taskYIELD();
}
}
set_ipl( configKERNEL_INTERRUPT_PRIORITY );
}
/*-----------------------------------------------------------*/
void vSoftwareInterruptISR( void )
{
prvYieldHandler();
}
/*-----------------------------------------------------------*/
#pragma inline_asm prvYieldHandler
static void prvYieldHandler( void )
{
/* Re-enable interrupts. */
SETPSW I
/* Move the data that was automatically pushed onto the interrupt stack when
* the interrupt occurred from the interrupt stack to the user stack.
*
* R15 is saved before it is clobbered. */
PUSH.L R15
/* Read the user stack pointer. */
MVFC USP, R15
/* Move the address down to the data being moved. */
SUB # 12, R15
MVTC R15, USP
/* Copy the data across. */
MOV.L[ R0 ], [ R15 ];
R15
MOV.L 4[ R0 ], 4[ R15 ];
PC
MOV.L 8[ R0 ], 8[ R15 ];
PSW
/* Move the interrupt stack pointer to its new correct position. */
ADD # 12, R0
/* All the rest of the registers are saved directly to the user stack. */
SETPSW U
/* Save the rest of the general registers (R15 has been saved already). */
PUSHM R1 - R14
/* Save the FPSW and accumulator. */
MVFC FPSW, R15
PUSH.L R15
MVFACHI R15
PUSH.L R15
MVFACMI R15;
Middle order word.
SHLL # 16, R15;
Shifted left as it is restored to the low order word.
PUSH.L R15
/* Save the stack pointer to the TCB. */
MOV.L # _pxCurrentTCB, R15
MOV.L[ R15 ], R15
MOV.L R0, [ R15 ]
/* Ensure the interrupt mask is set to the syscall priority while the kernel
* structures are being accessed. */
MVTIPL # configMAX_SYSCALL_INTERRUPT_PRIORITY
/* Select the next task to run. */
BSR.A _vTaskSwitchContext
/* Reset the interrupt mask as no more data structure access is required. */
MVTIPL # configKERNEL_INTERRUPT_PRIORITY
/* Load the stack pointer of the task that is now selected as the Running
* state task from its TCB. */
MOV.L # _pxCurrentTCB, R15
MOV.L[ R15 ], R15
MOV.L[ R15 ], R0
/* Restore the context of the new task. The PSW (Program Status Word) and
* PC will be popped by the RTE instruction. */
POP R15
MVTACLO R15
POP R15
MVTACHI R15
POP R15
MVTC R15, FPSW
POPM R1 - R15
RTE
NOP
NOP
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
/* Not implemented in ports where there is nothing to return to.
* Artificially force an assert. */
configASSERT( pxCurrentTCB == NULL );
/* The following line is just to prevent the symbol getting optimised away. */
( void ) vTaskSwitchContext();
}
/*-----------------------------------------------------------*/