mcf5235/clock/clock.c

0001 /*
0002  * Use the last periodic interval timer (PIT3) as the system clock.
0003  */
0004
0005 #include <rtems.h>
0006 #include <bsp.h>
0007 #include <mcf5235/mcf5235.h>
0008
0009 /*
0010  * Use INTC0 base
0011  */
0012 #define CLOCK_VECTOR (64+39)
0013
0014 /*
0015  * Periodic interval timer interrupt handler
0016  */
0017 #define Clock_driver_support_at_tick(arg)          \
0018     do {                                           \
0019         MCF5235_PIT_PCSR3 |= MCF5235_PIT_PCSR_PIF; \
0020     } while (0)                                    \
0021
0022 /*
0023  * Attach clock interrupt handler
0024  */
0025 #define Clock_driver_support_install_isr( _new ) \
0026     set_vector(_new, CLOCK_VECTOR, 1)
0027
0028 /*
0029  * Set up the clock hardware
0030  *
0031  * We need to have 1 interrupt every 10,000 microseconds
0032  * so we need to set prescaler to 64 and the PMR register to 0x2DC6
0033  */
0034 #define Clock_driver_support_initialize_hardware()                       \
0035     do {                                                                 \
0036         int level;                                                       \
0037         int preScaleCode = 6;                                            \
0038         MCF5235_INTC0_ICR39 = MCF5235_INTC_ICR_IL(PIT3_IRQ_LEVEL) |      \
0039                               MCF5235_INTC_ICR_IP(PIT3_IRQ_PRIORITY);    \
0040         rtems_interrupt_disable( level );                                \
0041         MCF5235_INTC0_IMRH &= ~MCF5235_INTC0_IMRH_INT39;                  \
0042     MCF5235_PIT_PCSR3 &= ~MCF5235_PIT_PCSR_EN;               \
0043         rtems_interrupt_enable( level );                                 \
0044         MCF5235_PIT_PMR3 = 0x2DC6;                               \
0045         MCF5235_PIT_PCSR3 = MCF5235_PIT_PCSR_PRE(preScaleCode) | \
0046                             MCF5235_PIT_PCSR_PIE |                       \
0047                             MCF5235_PIT_PCSR_RLD |                       \
0048                             MCF5235_PIT_PCSR_EN;                         \
0049     } while (0)
0050
0051 #define CLOCK_DRIVER_USE_DUMMY_TIMECOUNTER
0052
0053 #include "../../../shared/dev/clock/clockimpl.h"