/*
* FreeRTOS Kernel V10.6.2
* 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 RISC-V port.
*----------------------------------------------------------*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "portmacro.h"
/* Standard includes. */
#include "string.h"
#ifdef configCLINT_BASE_ADDRESS
#warning The configCLINT_BASE_ADDRESS constant has been deprecated. configMTIME_BASE_ADDRESS and configMTIMECMP_BASE_ADDRESS are currently being derived from the (possibly 0) configCLINT_BASE_ADDRESS setting. Please update to define configMTIME_BASE_ADDRESS and configMTIMECMP_BASE_ADDRESS dirctly in place of configCLINT_BASE_ADDRESS. See https: /*www.FreeRTOS.org/Using-FreeRTOS-on-RISC-V.html */
#endif
#ifndef configMTIME_BASE_ADDRESS
#warning configMTIME_BASE_ADDRESS must be defined in FreeRTOSConfig.h. If the target chip includes a memory-mapped mtime register then set configMTIME_BASE_ADDRESS to the mapped address. Otherwise set configMTIME_BASE_ADDRESS to 0. See https: /*www.FreeRTOS.org/Using-FreeRTOS-on-RISC-V.html */
#endif
#ifndef configMTIMECMP_BASE_ADDRESS
#warning configMTIMECMP_BASE_ADDRESS must be defined in FreeRTOSConfig.h. If the target chip includes a memory-mapped mtimecmp register then set configMTIMECMP_BASE_ADDRESS to the mapped address. Otherwise set configMTIMECMP_BASE_ADDRESS to 0. See https: /*www.FreeRTOS.org/Using-FreeRTOS-on-RISC-V.html */
#endif
/* Let the user override the pre-loading of the initial LR with the address of
* prvTaskExitError() in case it messes up unwinding of the stack in the
* debugger. */
#ifdef configTASK_RETURN_ADDRESS
#define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS
#else
#define portTASK_RETURN_ADDRESS prvTaskExitError
#endif
/* The stack used by interrupt service routines. Set configISR_STACK_SIZE_WORDS
* to use a statically allocated array as the interrupt stack. Alternative leave
* configISR_STACK_SIZE_WORDS undefined and update the linker script so that a
* linker variable names __freertos_irq_stack_top has the same value as the top
* of the stack used by main. Using the linker script method will repurpose the
* stack that was used by main before the scheduler was started for use as the
* interrupt stack after the scheduler has started. */
#ifdef configISR_STACK_SIZE_WORDS
static __attribute__( ( aligned( 16 ) ) ) StackType_t xISRStack[ configISR_STACK_SIZE_WORDS ] = { 0 };
const StackType_t xISRStackTop = ( StackType_t ) &( xISRStack[ configISR_STACK_SIZE_WORDS & ~portBYTE_ALIGNMENT_MASK ] );
/* Don't use 0xa5 as the stack fill bytes as that is used by the kernerl for
* the task stacks, and so will legitimately appear in many positions within
* the ISR stack. */
#define portISR_STACK_FILL_BYTE 0xee
#else
extern const uint32_t __freertos_irq_stack_top[];
const StackType_t xISRStackTop = ( StackType_t ) __freertos_irq_stack_top;
#endif
/**
* @brief Used to catch tasks that attempt to return from their implementing
* function.
*/
static void prvTaskExitError( void );
/*
* Setup the timer to generate the tick interrupts. The implementation in this
* file is weak to allow application writers to change the timer used to
* generate the tick interrupt.
*/
void vPortSetupTimerInterrupt( void ) __attribute__( ( weak ) );
/*-----------------------------------------------------------*/
/* Used to program the machine timer compare register. */
uint64_t ullNextTime = 0ULL;
const uint64_t * pullNextTime = &ullNextTime;
const size_t uxTimerIncrementsForOneTick = ( size_t ) ( ( configCPU_CLOCK_HZ ) / ( configTICK_RATE_HZ ) ); /* Assumes increment won't go over 32-bits. */
uint32_t const ullMachineTimerCompareRegisterBase = configMTIMECMP_BASE_ADDRESS;
volatile uint64_t * pullMachineTimerCompareRegister = NULL;
/* Holds the critical nesting value - deliberately non-zero at start up to
* ensure interrupts are not accidentally enabled before the scheduler starts. */
size_t xCriticalNesting = ( size_t ) 0xaaaaaaaa;
size_t * pxCriticalNesting = &xCriticalNesting;
/* Used to catch tasks that attempt to return from their implementing function. */
size_t xTaskReturnAddress = ( size_t ) portTASK_RETURN_ADDRESS;
/* Set configCHECK_FOR_STACK_OVERFLOW to 3 to add ISR stack checking to task
* stack checking. A problem in the ISR stack will trigger an assert, not call
* the stack overflow hook function (because the stack overflow hook is specific
* to a task stack, not the ISR stack). */
#if defined( configISR_STACK_SIZE_WORDS ) && ( configCHECK_FOR_STACK_OVERFLOW > 2 )
#warning This path not tested, or even compiled yet.
static const uint8_t ucExpectedStackBytes[] =
{
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE
}; \
#define portCHECK_ISR_STACK() configASSERT( ( memcmp( ( void * ) xISRStack, ( void * ) ucExpectedStackBytes, sizeof( ucExpectedStackBytes ) ) == 0 ) )
#else /* if defined( configISR_STACK_SIZE_WORDS ) && ( configCHECK_FOR_STACK_OVERFLOW > 2 ) */
/* Define the function away. */
#define portCHECK_ISR_STACK()
#endif /* configCHECK_FOR_STACK_OVERFLOW > 2 */
/*-----------------------------------------------------------*/
static void prvTaskExitError( void )
{
volatile uint32_t ulDummy = 0UL;
/* A function that implements a task must not exit or attempt to return to
* its caller as there is nothing to return to. If a task wants to exit it
* should instead call vTaskDelete( NULL ). Artificially force an assert()
* to be triggered if configASSERT() is defined, then stop here so
* application writers can catch the error. */
configASSERT( xCriticalNesting == ~0UL );
portDISABLE_INTERRUPTS();
while( ulDummy == 0 )
{
/* This file calls prvTaskExitError() after the scheduler has been
* started to remove a compiler warning about the function being
* defined but never called. ulDummy is used purely to quieten other
* warnings about code appearing after this function is called - making
* ulDummy volatile makes the compiler think the function could return
* and therefore not output an 'unreachable code' warning for code that
* appears after it. */
}
}
/*-----------------------------------------------------------*/
#if ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 )
void vPortSetupTimerInterrupt( void )
{
uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
volatile uint32_t * const pulTimeHigh = ( uint32_t * ) ( ( configMTIME_BASE_ADDRESS ) + 4UL ); /* 8-byte type so high 32-bit word is 4 bytes up. */
volatile uint32_t * const pulTimeLow = ( uint32_t * ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t ulHartId;
__asm volatile ( "csrr %0, 0xf14" : "=r" ( ulHartId ) ); /* 0xf14 is hartid. */
pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
do
{
ulCurrentTimeHigh = *pulTimeHigh;
ulCurrentTimeLow = *pulTimeLow;
} while( ulCurrentTimeHigh != *pulTimeHigh );
ullNextTime = ( uint64_t ) ulCurrentTimeHigh;
ullNextTime <<= 32ULL; /* High 4-byte word is 32-bits up. */
ullNextTime |= ( uint64_t ) ulCurrentTimeLow;
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
*pullMachineTimerCompareRegister = ullNextTime;
/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIME_BASE_ADDRESS != 0 ) */
/*-----------------------------------------------------------*/
BaseType_t xPortStartScheduler( void )
{
extern void xPortStartFirstTask( void );
#if ( configASSERT_DEFINED == 1 )
{
/* Check alignment of the interrupt stack - which is the same as the
* stack that was being used by main() prior to the scheduler being
* started. */
configASSERT( ( xISRStackTop & portBYTE_ALIGNMENT_MASK ) == 0 );
#ifdef configISR_STACK_SIZE_WORDS
{
memset( ( void * ) xISRStack, portISR_STACK_FILL_BYTE, sizeof( xISRStack ) );
}
#endif /* configISR_STACK_SIZE_WORDS */
}
#endif /* configASSERT_DEFINED */
/* If there is a CLINT then it is ok to use the default implementation
* in this file, otherwise vPortSetupTimerInterrupt() must be implemented to
* configure whichever clock is to be used to generate the tick interrupt. */
vPortSetupTimerInterrupt();
#if ( ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 ) )
{
/* Enable mtime and external interrupts. 1<<7 for timer interrupt,
* 1<<11 for external interrupt. _RB_ What happens here when mtime is
* not present as with pulpino? */
__asm volatile ( "csrs 0x304, %0" ::"r" ( 0x880 ) ); /* 0x304 is mie. */
}
#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 ) */
xPortStartFirstTask();
/* Should not get here as after calling xPortStartFirstTask() only tasks
* should be executing. */
return pdFAIL;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
/* Not implemented. */
for( ; ; )
{
}
}
/*-----------------------------------------------------------*/