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Update Cortex-M3 and Cortex-M4F ports to allow the SysTick to be clocked at a different speed than the system clock (as is done in the recent STM32L demo. ).

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Add additional asserts and isb instructions into the Cortex-M3 and Cortex-M4F ports.
This commit is contained in:
Richard Barry 2013-12-12 14:07:20 +00:00
parent 6b3393b4b6
commit 0d1e12522b
10 changed files with 110 additions and 67 deletions
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22
FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
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@ -243,6 +243,7 @@ __asm void vPortSVCHandler( void )
ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
ldmia r0!, {r4-r11} /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */
msr psp, r0 /* Restore the task stack pointer. */
isb
mov r0, #0
msr basepri, r0
orr r14, #0xd
@ -262,6 +263,8 @@ __asm void prvStartFirstTask( void )
msr msp, r0
/* Globally enable interrupts. */
cpsie i
dsb
isb
/* Call SVC to start the first task. */
svc 0
nop
@ -385,6 +388,7 @@ __asm void xPortPendSVHandler( void )
PRESERVE8
mrs r0, psp
isb
ldr r3, =pxCurrentTCB /* Get the location of the current TCB. */
ldr r2, [r3]
@ -404,6 +408,7 @@ __asm void xPortPendSVHandler( void )
ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
ldmia r0!, {r4-r11} /* Pop the registers and the critical nesting count. */
msr psp, r0
isb
bx r14
nop
}
@ -433,7 +438,7 @@ void xPortSysTickHandler( void )
__weak void vPortSuppressTicksAndSleep( portTickType xExpectedIdleTime )
{
unsigned long ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
unsigned long ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL;
portTickType xModifiableIdleTime;
/* Make sure the SysTick reload value does not overflow the counter. */
@ -446,7 +451,7 @@ void xPortSysTickHandler( void )
is accounted for as best it can be, but using the tickless mode will
inevitably result in some tiny drift of the time maintained by the
kernel with respect to calendar time. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT;
portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
/* Calculate the reload value required to wait xExpectedIdleTime
tick periods. -1 is used because this code will execute part way
@ -470,7 +475,7 @@ void xPortSysTickHandler( void )
portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
/* Reset the reload register to the value required for normal tick
periods. */
@ -490,7 +495,7 @@ void xPortSysTickHandler( void )
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
set its parameter to 0 to indicate that its implementation contains
@ -511,13 +516,14 @@ void xPortSysTickHandler( void )
accounted for as best it can be, but using the tickless mode will
inevitably result in some tiny drift of the time maintained by the
kernel with respect to calendar time. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT;
ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG;
portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT );
/* Re-enable interrupts - see comments above __disable_irq() call
above. */
__enable_irq();
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
{
unsigned long ulCalculatedLoadValue;
@ -569,7 +575,7 @@ void xPortSysTickHandler( void )
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
portENTER_CRITICAL();
{
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
vTaskStepTick( ulCompleteTickPeriods );
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
}
@ -600,7 +606,7 @@ void xPortSysTickHandler( void )
/* 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;
portNVIC_SYSTICK_CTRL_REG |= ( portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );
}
#endif /* configOVERRIDE_DEFAULT_TICK_CONFIGURATION */