RISC-V port updates: The machine timer compare register can now be for any HART, and correct the sequence used to update the 64-bit machine timer compare register on 32-bit cores.

FreeRTOS/Source/portable/GCC/RISC-V/port.c

@@ -75,7 +75,8 @@ void vPortSetupTimerInterrupt( void ) __attribute__(( weak ));
 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. */
-volatile uint64_t * const pullMachineTimerCompareRegister = ( volatile uint64_t * const ) ( configCLINT_BASE_ADDRESS + 0x4000 );
+volatile uint64_t * const pullMachineTimerCompareRegisterBase = ( volatile uint64_t * const ) ( configCLINT_BASE_ADDRESS + 0x4000 );
+volatile uint64_t * pullMachineTimerCompareRegister = 0;
 
 /* 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
@@ -110,6 +111,10 @@ task stack, not the ISR stack). */
 	uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
 	volatile uint32_t * const pulTimeHigh = ( volatile uint32_t * const ) ( configCLINT_BASE_ADDRESS + 0xBFFC );
 	volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configCLINT_BASE_ADDRESS + 0xBFF8 );
+	volatile uint32_t ulHartId = 0;
+
+		__asm volatile( "csrr %0, mhartid" : "=r"( ulHartId ) );
+		pullMachineTimerCompareRegister  = &( pullMachineTimerCompareRegisterBase[ ulHartId ] );
 
 		do
 		{

FreeRTOS/Source/portable/GCC/RISC-V/portASM.S

@@ -92,11 +92,13 @@ at the top of this file. */
 .extern pxCurrentTCB
 .extern ulPortTrapHandler
 .extern vTaskSwitchContext
+.extern xTaskIncrementTick
 .extern Timer_IRQHandler
 .extern pullMachineTimerCompareRegister
 .extern pullNextTime
 .extern uxTimerIncrementsForOneTick /* size_t type so 32-bit on 32-bit core and 64-bits on 64-bit core. */
 .extern xISRStackTop
+.extern portasmHANDLE_INTERRUPT
 
 /*-----------------------------------------------------------*/
 
@@ -167,10 +169,12 @@ handle_asynchronous:
 		#if( __riscv_xlen == 32 )
 
 			/* Update the 64-bit mtimer compare match value in two 32-bit writes. */
+			li t4, -1
 			lw t2, 0(t1)				/* Load the low word of ullNextTime into t2. */
 			lw t3, 4(t1)				/* Load the high word of ullNextTime into t3. */
+			sw t4, 0(t0)				/* Low word no smaller than old value. */
+			sw t3, 4(t0)				/* Store high word of ullNextTime into compare register.  No smaller than new value. */
 			sw t2, 0(t0)				/* Store low word of ullNextTime into compare register. */
-			sw t3, 4(t0)				/* Store high word of ullNextTime into compare register. */
 			lw t0, uxTimerIncrementsForOneTick	/* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
 			add t4, t0, t2				/* Add the low word of ullNextTime to the timer increments for one tick (assumes timer increment for one tick fits in 32-bits). */
 			sltu t5, t4, t2				/* See if the sum of low words overflowed (what about the zero case?). */

FreeRTOS/Source/portable/IAR/RISC-V/chip_specific_extensions/Pulpino_Vega_RV32M1RM/freertos_risc_v_chip_specific_extensions.h

@@ -1,109 +0,0 @@
-/*
- * FreeRTOS Kernel V10.2.1
- * Copyright (C) 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
- *
- * 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 t
-
- o 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.
- *
- * http://www.FreeRTOS.org
- * http://aws.amazon.com/freertos
- *
- * 1 tab == 4 spaces!
- */
-
-/*
- * The FreeRTOS kernel's RISC-V port is split between the the code that is
- * common across all currently supported RISC-V chips (implementations of the
- * RISC-V ISA), and code that tailors the port to a specific RISC-V chip:
- *
- * + FreeRTOS\Source\portable\GCC\RISC-V-RV32\portASM.S contains the code that
- *   is common to all currently supported RISC-V chips.  There is only one
- *   portASM.S file because the same file is built for all RISC-V target chips.
- *
- * + Header files called freertos_risc_v_chip_specific_extensions.h contain the
- *   code that tailors the FreeRTOS kernel's RISC-V port to a specific RISC-V
- *   chip.  There are multiple freertos_risc_v_chip_specific_extensions.h files
- *   as there are multiple RISC-V chip implementations.
- *
- * !!!NOTE!!!
- * TAKE CARE TO INCLUDE THE CORRECT freertos_risc_v_chip_specific_extensions.h
- * HEADER FILE FOR THE CHIP IN USE.  This is done using the assembler's (not the
- * compiler's!) include path.  For example, if the chip in use includes a core
- * local interrupter (CLINT) and does not include any chip specific register
- * extensions then add the path below to the assembler's include path:
- * FreeRTOS\Source\portable\GCC\RISC-V-RV32\chip_specific_extensions\RV32I_CLINT_no_extensions
- *
- */
-
-/*
- * This freertos_risc_v_chip_specific_extensions.h is for use with Pulpino Ri5cy
- * devices, developed and tested using the Vega board RV32M1RM.
- */
-
-#ifndef __FREERTOS_RISC_V_EXTENSIONS_H__
-#define __FREERTOS_RISC_V_EXTENSIONS_H__
-
-#define portasmHAS_CLINT 0
-
-/* Constants to define the additional registers found on the Pulpino RI5KY. */
-#define lpstart0 	0x7b0
-#define lpend0 		0x7b1
-#define lpcount0 	0x7b2
-#define lpstart1 	0x7b4
-#define lpend1 		0x7b5
-#define lpcount1 	0x7b6
-
-/* Six additional registers to save and restore, as per the #defines above. */
-#define portasmADDITIONAL_CONTEXT_SIZE 6 /* Must be even number on 32-bit cores. */
-
-/* Save additional registers found on the Pulpino. */
-.macro portasmSAVE_ADDITIONAL_REGISTERS
-	addi sp, sp, -(portasmADDITIONAL_CONTEXT_SIZE * portWORD_SIZE) /* Make room for the additional registers. */
-	csrr t0, lpstart0							 /* Load additional registers into accessible temporary registers. */
-	csrr t1, lpend0
-	csrr t2, lpcount0
-	csrr t3, lpstart1
-	csrr t4, lpend1
-	csrr t5, lpcount1
-	sw t0, 1 * portWORD_SIZE( sp )
-	sw t1, 2 * portWORD_SIZE( sp )
-	sw t2, 3 * portWORD_SIZE( sp )
-	sw t3, 4 * portWORD_SIZE( sp )
-	sw t4, 5 * portWORD_SIZE( sp )
-	sw t5, 6 * portWORD_SIZE( sp )
-	.endm
-
-/* Restore the additional registers found on the Pulpino. */
-.macro portasmRESTORE_ADDITIONAL_REGISTERS
-	lw t0, 1 * portWORD_SIZE( sp )			/* Load additional registers into accessible temporary registers. */
-	lw t1, 2 * portWORD_SIZE( sp )
-	lw t2, 3 * portWORD_SIZE( sp )
-	lw t3, 4 * portWORD_SIZE( sp )
-	lw t4, 5 * portWORD_SIZE( sp )
-	lw t5, 6 * portWORD_SIZE( sp )
-	csrw lpstart0, t0
-	csrw lpend0, t1
-	csrw lpcount0, t2
-	csrw lpstart1, t3
-	csrw lpend1, t4
-	csrw lpcount1, t5
-	addi sp, sp, (portasmADDITIONAL_CONTEXT_SIZE * portWORD_SIZE )/* Remove space added for additional registers. */
-	.endm
-
-#endif /* __FREERTOS_RISC_V_EXTENSIONS_H__ */

FreeRTOS/Source/portable/IAR/RISC-V/port.c

@@ -56,7 +56,7 @@ 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 };
-	StackType_t xISRStackTop = ( StackType_t ) 0;
+	const StackType_t xISRStackTop = ( StackType_t ) &( xISRStack[ configISR_STACK_SIZE_WORDS & ~portBYTE_ALIGNMENT_MASK ] );
 #else
 	extern const uint32_t __freertos_irq_stack_top[];
 	const StackType_t xISRStackTop = ( StackType_t ) __freertos_irq_stack_top;
@@ -75,7 +75,8 @@ void vPortSetupTimerInterrupt( void ) __attribute__(( weak ));
 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. */
-volatile uint64_t * const pullMachineTimerCompareRegister = ( uint64_t * ) ( configCLINT_BASE_ADDRESS + 0x4000 );
+volatile uint64_t * const pullMachineTimerCompareRegisterBase = ( uint64_t * ) ( configCLINT_BASE_ADDRESS + 0x4000 );
+volatile uint64_t * pullMachineTimerCompareRegister = 0;
 
 /* 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
@@ -110,6 +111,10 @@ task stack, not the ISR stack). */
 	uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
 	volatile uint32_t * const pulTimeHigh = ( uint32_t * ) ( configCLINT_BASE_ADDRESS + 0xBFFC );
 	volatile uint32_t * const pulTimeLow = ( uint32_t * ) ( configCLINT_BASE_ADDRESS + 0xBFF8 );
+	volatile uint32_t ulHartId = 0;
+
+		__asm volatile( "csrr %0, 0xf14" : "=r"( ulHartId ) ); /* 0xf14 is hartid. */
+		pullMachineTimerCompareRegister  = &( pullMachineTimerCompareRegisterBase[ ulHartId ] );
 
 		do
 		{
@@ -133,10 +138,6 @@ task stack, not the ISR stack). */
 BaseType_t xPortStartScheduler( void )
 {
 extern void xPortStartFirstTask( void );
-#warning Replicate this change in the GCC version.
-	#ifdef configISR_STACK_SIZE_WORDS
-		xISRStackTop = ( ( StackType_t ) &( xISRStack[ configISR_STACK_SIZE_WORDS - 1 ] ) & ~portBYTE_ALIGNMENT_MASK );
-	#endif
 
 	#if( configASSERT_DEFINED == 1 )
 	{

FreeRTOS/Source/portable/IAR/RISC-V/portASM.s

@@ -177,10 +177,12 @@ handle_asynchronous:
 		#if( __riscv_xlen == 32 )
 
 			/* Update the 64-bit mtimer compare match value in two 32-bit writes. */
+			li t4, -1
 			lw t2, 0(t1)				/* Load the low word of ullNextTime into t2. */
 			lw t3, 4(t1)				/* Load the high word of ullNextTime into t3. */
+			sw t4, 0(t0)				/* Low word no smaller than old value. */
+			sw t3, 4(t0)				/* Store high word of ullNextTime into compare register.  No smaller than new value. */
 			sw t2, 0(t0)				/* Store low word of ullNextTime into compare register. */
-			sw t3, 4(t0)				/* Store high word of ullNextTime into compare register. */
 			lw t0, uxTimerIncrementsForOneTick	/* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
 			add t4, t0, t2				/* Add the low word of ullNextTime to the timer increments for one tick (assumes timer increment for one tick fits in 32-bits). */
 			sltu t5, t4, t2				/* See if the sum of low words overflowed (what about the zero case?). */