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/**
* @file clockdrv.c
*
* Game Boy Advance Clock driver.
*/
/*
* RTEMS GBA BSP
*
* Copyright (c) 2004 Markku Puro <markku.puro@kopteri.net>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <rtems.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <gba.h>
#include <assert.h>
void Clock_isr(void * arg);
#define Clock_driver_support_at_tick()
#define Clock_driver_support_install_isr( _new, _old ) \
do { \
rtems_status_code status = RTEMS_SUCCESSFUL; \
status = rtems_interrupt_handler_install( \
BSP_IRQ_TIMER3, \
"Clock", \
RTEMS_INTERRUPT_UNIQUE, \
Clock_isr, \
NULL \
); \
assert(status == RTEMS_SUCCESSFUL); \
_old = NULL; \
} while(0)
#define Clock_driver_support_shutdown_hardware() \
do { \
rtems_status_code status = RTEMS_SUCCESSFUL; \
status = rtems_interrupt_handler_remove( \
BSP_IRQ_TIMER3, \
Clock_isr, \
NULL \
); \
assert(status == RTEMS_SUCCESSFUL); \
} while (0)
/*
* Calculate Tick Times
* 1 / 16.78Mhz => 59.595 ns
* 64 / 16.78Mhz => 3.814 us
* 256 / 16.78Mhz => 15.256 us
* 1024 / 16.78Mhz => 61.025 us
*/
#define __TimTickTime_us ((1000000L/__ClockFrequency)*__TimPreScaler)
#define __TimTickTime_ns ((1000000000L/__ClockFrequency)*__TimPreScaler)
#if (__TimPreScaler==1)
#define GBA_TMCNT_PS 0x0000
#elif (__TimPreScaler==64)
#define GBA_TMCNT_PS 0x0001
#elif (__TimPreScaler==256)
#define GBA_TMCNT_PS 0x0002
#elif (__TimPreScaler==1024)
#define GBA_TMCNT_PS 0x0003
#else
#define GBA_TMCNT_PS 0x0003
#endif
/**
* @brief This function set up the clock hardware
*
* @param None
* @return None
*/
void Clock_driver_support_initialize_hardware(void)
{
int tmreload = ((rtems_configuration_get_microseconds_per_tick()*1000)/__TimTickTime_ns);
if (tmreload>0xFFFF) tmreload = 0xFFFF;
GBA_REG_TM3CNT = (GBA_TMCNT_PS);
GBA_REG_TM3D = (0x0000-tmreload);
GBA_REG_TM3CNT = (0x00c0|GBA_TMCNT_PS);
}
#include "../../../shared/clockdrv_shell.h"
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