blob: a1e2782c31f0d477eff4016620229c5f62d89169 (
plain) (
tree)
|
|
/**
* @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 found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#include <rtems.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <gba.h>
/*-------------------------------------------------------------------------+
| Clock isr variables
+--------------------------------------------------------------------------*/
rtems_isr Clock_isr(rtems_vector_number vector);
static void clock_isr_on(const rtems_irq_connect_data *unused);
static void clock_isr_off(const rtems_irq_connect_data *unused);
static int clock_isr_is_on(const rtems_irq_connect_data *irq);
rtems_irq_connect_data clock_isr_data = {BSP_IRQ_TIMER3,
(rtems_irq_hdl)Clock_isr,
NULL,
clock_isr_on,
clock_isr_off,
clock_isr_is_on};
#define CLOCK_VECTOR 0
#define Clock_driver_support_at_tick()
#define Clock_driver_support_install_isr( _new, _old ) \
do { \
BSP_install_rtems_irq_handler(&clock_isr_data); \
_old = NULL; \
} while(0)
#define Clock_driver_support_shutdown_hardware() \
do { \
BSP_remove_rtems_irq_handler(&clock_isr_data); \
} 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);
}
/**
* @brief This function is empty
*
* @param unused an unused parameter
* @return None
*/
static void clock_isr_on(const rtems_irq_connect_data *unused)
{
return;
}
/**
* @brief This function is empty
*
* @param unused an unused parameter
* @return None
*/
static void clock_isr_off(const rtems_irq_connect_data *unused)
{
return;
}
/**
* @brief This function is empty
*
* @param irq unused
* @return constant 1
*/
static int clock_isr_is_on(const rtems_irq_connect_data *irq)
{
return 1;
}
#include "../../../shared/clockdrv_shell.h"
|