/* | |
* 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 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( ; ; ) | |
{ | |
} | |
} | |
/*-----------------------------------------------------------*/ |