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/*
* This routine initializes the Z80386 1 on the MVME136 board.
* The tick frequency is 1 millisecond.
*/
/*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* 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 <stdlib.h>
#include <bsp.h>
#include <rtems/zilog/z8036.h>
#define MICRVAL 0xe2 /* disable lower chain, no vec */
/* set right justified addr */
/* and master int enable */
#define MCCRVAL 0xc4 /* enable T1 and port B */
/* timers independent */
#define MS_COUNT 0x07d0 /* T1's countdown constant (1 ms) */
#define T1MSRVAL 0x80 /* T1 cont. cycle/pulse output */
#define T1CSRVAL 0xc6 /* enable interrupt, allow and */
/* and trigger countdown */
#define TIMER 0xfffb0000
#define RELOAD 0x24 /* clr IP & IUS,allow countdown */
#define CLOCK_VECTOR 66
uint32_t Clock_isrs; /* ISRs until next tick */
volatile uint32_t Clock_driver_ticks; /* ticks since initialization */
rtems_isr_entry Old_ticker;
void Clock_exit( void );
/*
* ISR Handler
*/
static rtems_isr Clock_isr(
rtems_vector_number vector
)
{
Clock_driver_ticks += 1;
((volatile struct z8036_map *) TIMER)->CT1_CMD_STATUS = RELOAD;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
}
else
Clock_isrs -= 1;
}
static void Install_clock(
rtems_isr_entry clock_isr
)
{
volatile struct z8036_map *timer;
Clock_driver_ticks = 0;
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
timer = (struct z8036_map *) 0xfffb0000;
timer->MASTER_INTR = MICRVAL;
timer->CT1_MODE_SPEC = T1MSRVAL;
*((uint16_t*)0xfffb0016) = MS_COUNT; /* write countdown value */
/*
* timer->CT1_TIME_CONST_MSB = (MS_COUNT >> 8);
* timer->CT1_TIME_CONST_LSB = (MS_COUNT & 0xff);
*/
timer->MASTER_CFG = MCCRVAL;
timer->CT1_CMD_STATUS = T1CSRVAL;
/*
* Enable interrupt via VME interrupt mask register
*/
(*(uint8_t*)0xfffb0038) &= 0xfd;
atexit( Clock_exit );
}
void Clock_exit( void )
{
volatile struct z8036_map *timer;
timer = (struct z8036_map *) 0xfffb0000;
timer->MASTER_INTR = 0x62;
timer->CT1_MODE_SPEC = 0x00;
timer->MASTER_CFG = 0xf4;
timer->CT1_CMD_STATUS = 0x00;
/* do not restore old vector */
}
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
return RTEMS_SUCCESSFUL;
}
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