forked from Imagelibrary/rtems
109 lines
2.6 KiB
C
109 lines
2.6 KiB
C
/*
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* Use the last periodic interval timer (PIT2) as the system clock.
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*/
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#include <rtems.h>
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#include <rtems/timecounter.h>
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#include <bsp.h>
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/*
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* Use INTC0 base
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*/
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#define CLOCK_VECTOR (64+56)
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static rtems_timecounter_simple mcf5225x_tc;
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static uint32_t mcf5225x_tc_get(rtems_timecounter_simple *tc)
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{
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return MCF_PIT1_PCNTR;
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}
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static bool mcf5225x_tc_is_pending(rtems_timecounter_simple *tc)
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{
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return (MCF_PIT1_PCSR & MCF_PIT_PCSR_PIF) != 0;
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}
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static uint32_t mcf5225x_tc_get_timecount(struct timecounter *tc)
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{
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return rtems_timecounter_simple_downcounter_get(
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tc,
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mcf5225x_tc_get,
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mcf5225x_tc_is_pending
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);
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}
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static void mcf5225x_tc_tick(void)
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{
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rtems_timecounter_simple_downcounter_tick(&mcf5225x_tc, mcf5225x_tc_get);
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}
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/*
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* Periodic interval timer interrupt handler
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*/
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#define Clock_driver_support_at_tick() \
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do { \
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MCF_PIT1_PCSR |= MCF_PIT_PCSR_PIF; \
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} while (0) \
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/*
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* Attach clock interrupt handler
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*/
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#define Clock_driver_support_install_isr( _new, _old ) \
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do { \
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_old = (rtems_isr_entry)set_vector(_new, CLOCK_VECTOR, 1); \
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} while(0)
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/*
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* Turn off the clock
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*/
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static void Clock_driver_support_shutdown_hardware(void)
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{
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MCF_PIT1_PCSR &= ~MCF_PIT_PCSR_EN;
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}
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/*
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* Set up the clock hardware
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*
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* We need to have 1 interrupt every BSP_rtems_configuration_get_microseconds_per_tick()
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*/
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static void Clock_driver_support_initialize_hardware(void)
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{
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uint32_t mask;
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int level;
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uint32_t pmr;
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uint32_t preScaleCode = 0;
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uint32_t clk = bsp_get_CPU_clock_speed() >> 1;
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uint32_t tps = 1000000 / rtems_configuration_get_microseconds_per_tick();
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while (preScaleCode < 15) {
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pmr = (clk >> preScaleCode) / tps;
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if (pmr < (1 << 15))
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break;
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preScaleCode++;
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}
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MCF_INTC0_ICR56 = MCF_INTC_ICR_IL(PIT3_IRQ_LEVEL) |
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MCF_INTC_ICR_IP(PIT3_IRQ_PRIORITY);
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rtems_interrupt_disable(level);
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MCF_INTC0_IMRH &= ~MCF_INTC_IMRH_MASK56;
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MCF_PIT1_PCSR &= ~MCF_PIT_PCSR_EN;
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rtems_interrupt_enable(level);
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MCF_PIT1_PCSR = MCF_PIT_PCSR_PRE(preScaleCode) |
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MCF_PIT_PCSR_OVW | MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD;
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MCF_PIT1_PMR = pmr;
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MCF_PIT1_PCSR = MCF_PIT_PCSR_PRE(preScaleCode) |
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MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_EN;
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rtems_timecounter_simple_install(
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&mcf5225x_tc,
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clk >> preScaleCode,
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pmr,
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mcf5225x_tc_get_timecount
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);
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}
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#define Clock_driver_timecounter_tick() mcf5225x_tc_tick()
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#include "../../../shared/clockdrv_shell.h"
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