Improvements to the Cortex-M ports:

- Clear the SysTick current value register before starting the SysTick (only required if something uses SysTick before starting the scheduler).
- Ensure atomic operations are thread safe by executing clrex in the context switch.

git-svn-id: http://svn.code.sf.net/p/freertos/code/trunk@2465 1d2547de-c912-0410-9cb9-b8ca96c0e9e2

5 files changed, 40 insertions, 10 deletions

diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM0/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM0/port.c
index 6fc1e94b6..1de444935 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM0/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM0/port.c
@@ -76,8 +76,9 @@
 #include "task.h"

 

 /* Constants required to manipulate the NVIC. */

-#define portNVIC_SYSTICK_CTRL		( ( volatile uint32_t *) 0xe000e010 )

-#define portNVIC_SYSTICK_LOAD		( ( volatile uint32_t *) 0xe000e014 )

+#define portNVIC_SYSTICK_CTRL			( ( volatile uint32_t * ) 0xe000e010 )

+#define portNVIC_SYSTICK_LOAD			( ( volatile uint32_t * ) 0xe000e014 )

+#define portNVIC_SYSTICK_CURRENT_VALUE	( ( volatile uint32_t * ) 0xe000e018 )

 #define portNVIC_INT_CTRL			( ( volatile uint32_t *) 0xe000ed04 )

 #define portNVIC_SYSPRI2			( ( volatile uint32_t *) 0xe000ed20 )

 #define portNVIC_SYSTICK_CLK		0x00000004

@@ -341,6 +342,10 @@ uint32_t ulPreviousMask;
  */

 void prvSetupTimerInterrupt( void )

 {

+	/* Stop and reset the SysTick. */

+	*(portNVIC_SYSTICK_CTRL) = 0UL;

+	*(portNVIC_SYSTICK_CURRENT_VALUE) = 0UL;

+

 	/* Configure SysTick to interrupt at the requested rate. */

 	*(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;

 	*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;

diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
index 61d85967d..8ce6d098d 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
@@ -407,6 +407,7 @@ __asm void xPortPendSVHandler( void )
 

 	stmdb r0!, {r4-r11}			/* Save the remaining registers. */

 	str r0, [r2]				/* Save the new top of stack into the first member of the TCB. */

+	clrex						/* Ensure thread safety of atomic operations. */

 

 	stmdb sp!, {r3, r14}

 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

@@ -621,6 +622,10 @@ void xPortSysTickHandler( void )
 		}

 		#endif /* configUSE_TICKLESS_IDLE */

 

+		/* Stop and clear the SysTick. */

+		portNVIC_SYSTICK_CTRL_REG = 0UL;

+		portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;

+

 		/* Configure SysTick to interrupt at the requested rate. */

 		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;

 		portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );

diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
index 1dc1b5b00..aaf9efd21 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
@@ -479,6 +479,9 @@ __asm void xPortPendSVHandler( void )
 	/* Save the new top of stack into the first member of the TCB. */

 	str r0, [r2]

 

+	/* Ensure thread safety of atomic operations. */

+	clrex

+

 	stmdb sp!, {r3}

 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

 	msr basepri, r0

@@ -696,7 +699,7 @@ void xPortSysTickHandler( void )
  * Setup the SysTick timer to generate the tick interrupts at the required

  * frequency.

  */

-#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0

+#if( configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 )

 

 	void vPortSetupTimerInterrupt( void )

 	{

@@ -709,6 +712,10 @@ void xPortSysTickHandler( void )
 		}

 		#endif /* configUSE_TICKLESS_IDLE */

 

+		/* Stop and clear the SysTick. */

+		portNVIC_SYSTICK_CTRL_REG = 0UL;

+		portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;

+

 		/* Configure SysTick to interrupt at the requested rate. */

 		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;

 		portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );

diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c
index bbe2a96a8..0623859e8 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c
@@ -91,6 +91,7 @@ task.h is included from an application file. */
 /* Constants required to access and manipulate the NVIC. */

 #define portNVIC_SYSTICK_CTRL_REG				( * ( ( volatile uint32_t * ) 0xe000e010 ) )

 #define portNVIC_SYSTICK_LOAD_REG				( * ( ( volatile uint32_t * ) 0xe000e014 ) )

+#define portNVIC_SYSTICK_CURRENT_VALUE_REG		( * ( ( volatile uint32_t * ) 0xe000e018 ) )

 #define portNVIC_SYSPRI2_REG					( *	( ( volatile uint32_t * ) 0xe000ed20 ) )

 #define portNVIC_SYSPRI1_REG					( * ( ( volatile uint32_t * ) 0xe000ed1c ) )

 #define portNVIC_SYS_CTRL_STATE_REG				( * ( ( volatile uint32_t * ) 0xe000ed24 ) )

@@ -206,7 +207,7 @@ static void vPortEnableVFP( void );
  * Utility function.

  */

 static uint32_t prvPortGetIPSR( void );

-	

+

 /*

  * Used by the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() macro to ensure

  * FreeRTOS API functions are not called from interrupts that have been assigned

@@ -297,7 +298,7 @@ uint32_t ulReg;
 __asm void vPortSVCHandler( void )

 {

 	extern prvSVCHandler

-		

+

 	PRESERVE8

 

 	/* Assumes psp was in use. */

@@ -424,7 +425,7 @@ BaseType_t xPortStartScheduler( void )
 __asm void prvStartFirstTask( void )

 {

 	PRESERVE8

-	

+

 	ldr r0, =0xE000ED08	/* Use the NVIC offset register to locate the stack. */

 	ldr r0, [r0]

 	ldr r0, [r0]

@@ -491,6 +492,7 @@ __asm void xPortPendSVHandler( void )
 	mrs r1, control

 	stmdb r0!, {r1, r4-r11, r14}	/* Save the remaining registers. */

 	str r0, [r2]					/* Save the new top of stack into the first member of the TCB. */

+	clrex							/* Ensure thread safety of atomic operations. */

 

 	stmdb sp!, {r3}

 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

@@ -544,6 +546,10 @@ uint32_t ulDummy;
  */

 static void prvSetupTimerInterrupt( void )

 {

+	/* Reset the SysTick. */

+	portNVIC_SYSTICK_CTRL_REG = 0UL;

+	portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;

+

 	/* Configure SysTick to interrupt at the requested rate. */

 	portNVIC_SYSTICK_LOAD_REG = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;

 	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;

@@ -553,18 +559,18 @@ static void prvSetupTimerInterrupt( void )
 __asm void vPortSwitchToUserMode( void )

 {

 	PRESERVE8

-	

+

 	mrs r0, control

 	orr r0, #1

 	msr control, r0

 	bx r14

 }

 /*-----------------------------------------------------------*/

-	

+

 __asm void vPortEnableVFP( void )

 {

 	PRESERVE8

-	

+

 	ldr.w r0, =0xE000ED88		/* The FPU enable bits are in the CPACR. */

 	ldr r1, [r0]

 

@@ -682,7 +688,7 @@ extern uint32_t __SRAM_segment_end__;
 extern uint32_t __privileged_data_start__;

 extern uint32_t __privileged_data_end__;

 

-	

+

 int32_t lIndex;

 uint32_t ul;

 

diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c
index ef34402f6..9f0dc3330 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c
@@ -463,6 +463,9 @@ __asm void xPortPendSVHandler( void )
 	/* Save the new top of stack into the first member of the TCB. */

 	str r0, [r2]

 

+	/* Ensure thread safety of atomic operations. */

+	clrex

+

 	stmdb sp!, {r3}

 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

 	cpsid i

@@ -695,6 +698,10 @@ void xPortSysTickHandler( void )
 		}

 		#endif /* configUSE_TICKLESS_IDLE */

 

+		/* Stop and clear the SysTick. */

+		portNVIC_SYSTICK_CTRL_REG = 0UL;

+		portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;

+

 		/* Configure SysTick to interrupt at the requested rate. */

 		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;

 		portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );