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Improvements to the Cortex-M ports:

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- 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.
This commit is contained in:
Richard Barry 2016-06-27 13:13:05 +00:00
parent 6c975cd46a
commit c296e2cff8
23 changed files with 139 additions and 40 deletions
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20
FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c
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@ -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;