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Merged
n9wxu merged 4 commits into from
Sep 9, 2020
Merged

RISC-V: Add RV32E / FPU support for GCC #140

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d0d2442
Change vPortSetupTimerInterrupt in order to have 64bits access on rv64
e-puerto Aug 25, 2020
37aaa0a
Support RV32E - RISC-V architecture (GCC)
e-puerto Aug 26, 2020
fb9275d
Support FPU - RISC-V architecture (GCC)
e-puerto Aug 26, 2020
c291ffa
Fix interrupt managment and FPU initialization
e-puerto Sep 7, 2020
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137 changes: 91 additions & 46 deletions portable/GCC/RISC-V/port.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,9 +25,11 @@
* 1 tab == 4 spaces!
*/

/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the RISC-V RV32 port.
*----------------------------------------------------------*/
/* ------------------------------------------------------------------
* This file is part of the FreeRTOS distribution and was contributed
* to the project by SiFive
* ------------------------------------------------------------------
*/

/* Scheduler includes. */
#include "FreeRTOS.h"
Expand Down Expand Up @@ -118,31 +120,69 @@ task stack, not the ISR stack). */

#if( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 )

void vPortSetupTimerInterrupt( void )
{
uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
volatile uint32_t * const pulTimeHigh = ( volatile uint32_t * const ) ( ( configMTIME_BASE_ADDRESS ) + 4UL ); /* 8-byte typer so high 32-bit word is 4 bytes up. */
volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t ulHartId;

__asm volatile( "csrr %0, mhartid" : "=r"( ulHartId ) );
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;
}
#if( __riscv_xlen == 32 )
void vPortSetupTimerInterrupt( void )
{
uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
volatile uint32_t * const pulTimeHigh = ( volatile uint32_t * const ) ( ( configMTIME_BASE_ADDRESS ) + 4UL ); /* 8-byte typer so high 32-bit word is 4 bytes up. */
volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t * pulTimeCompareRegisterHigh;
volatile uint32_t * pulTimeCompareRegisterLow;

volatile uint32_t ulHartId;

__asm volatile ( "csrr %0, mhartid" : "=r" ( ulHartId ) );

/* pullMachineTimerCompareRegister is used by freertos_risc_v_trap_handler */
pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
pulTimeCompareRegisterLow = ( volatile uint32_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
pulTimeCompareRegisterHigh = ( volatile uint32_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) + 4UL );

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 );
/* Per spec, the RISC-V MTIME/MTIMECMP registers are 64 bit,
* and are NOT internally latched for multiword transfers.
* Need to be careful about sequencing to avoid triggering
* spurious interrupts: For that set the high word to a max
* value first.
*/
*pulTimeCompareRegisterHigh = 0xFFFFFFFF;
*pulTimeCompareRegisterLow = (uint32_t)( ullNextTime );
*pulTimeCompareRegisterHigh = (uint32_t)( ullNextTime >> 32ULL );

/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#endif /* __riscv_xlen == 32 */

#if( __riscv_xlen == 64 )
void vPortSetupTimerInterrupt( void )
{
volatile uint32_t * const pulTime = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );

volatile uint32_t ulHartId;

__asm volatile ( "csrr %0, mhartid" : "=r" ( ulHartId ) );

pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );

ullNextTime = *pulTime;

ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
*pullMachineTimerCompareRegister = ullNextTime;

/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#endif /* __riscv_xlen == 64 */

#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIME_BASE_ADDRESS != 0 ) */
/*-----------------------------------------------------------*/
Expand Down Expand Up @@ -178,20 +218,7 @@ extern void xPortStartFirstTask( void );
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 mie, %0" :: "r"(0x880) );
}
#else
{
/* Enable external interrupts. */
__asm volatile( "csrs mie, %0" :: "r"(0x800) );
}
#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 ) */

/* Enabling mtime and external interrupts will be made into xPortStartFirstTask function */
xPortStartFirstTask();

/* Should not get here as after calling xPortStartFirstTask() only tasks
Expand All @@ -205,8 +232,26 @@ void vPortEndScheduler( void )
/* Not implemented. */
for( ;; );
}
/*-----------------------------------------------------------*/





#if( configENABLE_FPU == 1 )
void vPortSetupFPU( void )
{
#ifdef __riscv_fdiv
__asm__ __volatile__ (
"csrr t0, misa \n" /* Get misa */
"li t1, 0x10028 \n" /* 0x10028 = Q,F,D Quad, Single or Double precission floating point */
"and t0, t0, t1 \n"
"beqz t0, 1f \n" /* check if Q,F or D is present into misa */
"csrr t0, mstatus \n" /* Floating point unit is present so need to put it into initial state */
"lui t1, 0x2 \n" /* t1 = 0x1 << 12 */
"or t0, t0, t1 \n"
"csrw mstatus, t0 \n" /* Set FS to initial state */
"csrwi fcsr, 0 \n" /* Clear Floating-point Control and Status Register */
"1: \n"
:::
);
#endif /* __riscv_fdiv */
}
#endif /* configENABLE_FPU */
/*-----------------------------------------------------------*/
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