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/*
* Use the last periodic interval timer (PIT2) as the system clock.
*/
#include <rtems.h>
#include <bsp.h>
/*
* Use INTC0 base
*/
#define CLOCK_VECTOR (64+56)
static uint32_t s_pcntrAtTick = 0;
static uint32_t s_nanoScale = 0;
/*
* Provide nanosecond extension
* Interrupts are disabled when this is called
*/
static uint32_t bsp_clock_nanoseconds_since_last_tick(void)
{
uint32_t i;
if (MCF_PIT1_PCSR & MCF_PIT_PCSR_PIF) {
i = s_pcntrAtTick + (MCF_PIT1_PMR - MCF_PIT1_PCNTR);
}
else {
i = s_pcntrAtTick - MCF_PIT1_PCNTR;
}
return i * s_nanoScale;
}
#define Clock_driver_nanoseconds_since_last_tick bsp_clock_nanoseconds_since_last_tick
/*
* Periodic interval timer interrupt handler
*/
#define Clock_driver_support_at_tick() \
do { \
s_pcntrAtTick = MCF_PIT1_PCNTR; \
MCF_PIT1_PCSR |= MCF_PIT_PCSR_PIF; \
} while (0) \
/*
* Attach clock interrupt handler
*/
#define Clock_driver_support_install_isr( _new, _old ) \
do { \
_old = (rtems_isr_entry)set_vector(_new, CLOCK_VECTOR, 1); \
} while(0)
/*
* Turn off the clock
*/
static void Clock_driver_support_shutdown_hardware(void)
{
MCF_PIT1_PCSR &= ~MCF_PIT_PCSR_EN;
}
/*
* Set up the clock hardware
*
* We need to have 1 interrupt every BSP_Configuration.microseconds_per_tick
*/
static void Clock_driver_support_initialize_hardware(void)
{
int level;
uint32_t pmr;
uint32_t preScaleCode = 0;
uint32_t clk = bsp_get_CPU_clock_speed() >> 1;
uint32_t tps = 1000000 / Configuration.microseconds_per_tick;
while (preScaleCode < 15) {
pmr = (clk >> preScaleCode) / tps;
if (pmr < (1 << 15))
break;
preScaleCode++;
}
s_nanoScale = 1000000000 / (clk >> preScaleCode);
MCF_INTC0_ICR56 = MCF_INTC_ICR_IL(PIT3_IRQ_LEVEL) |
MCF_INTC_ICR_IP(PIT3_IRQ_PRIORITY);
rtems_interrupt_disable(level);
MCF_INTC0_IMRH &= ~MCF_INTC_IMRH_MASK56;
MCF_PIT1_PCSR &= ~MCF_PIT_PCSR_EN;
rtems_interrupt_enable(level);
MCF_PIT1_PCSR = MCF_PIT_PCSR_PRE(preScaleCode) |
MCF_PIT_PCSR_OVW | MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD;
MCF_PIT1_PMR = pmr;
MCF_PIT1_PCSR = MCF_PIT_PCSR_PRE(preScaleCode) |
MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_EN;
s_pcntrAtTick = MCF_PIT1_PCNTR;
}
#include "../../../shared/clockdrv_shell.h"
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