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/*
* Clock Tick Device Driver
*
* This routine utilizes the Decrementer Register common to the PPC family.
*
* The tick frequency is directly programmed to the configured number of
* microseconds per tick.
*
* COPYRIGHT (c) 1989-1997.
* On-Line Applications Research Corporation (OAR).
* Copyright assigned to U.S. Government, 1994.
*
* The license and distribution terms for this file may in
* the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* Modified to support the MPC750.
* Modifications Copyright (c) 1999 Eric Valette valette@crf.canon.fr
*
* $Id$
*/
#include <rtems.h>
#include <rtems/libio.h>
#include <stdlib.h> /* for atexit() */
#include <assert.h>
#include <libcpu/cpu.h>
#include <libcpu/c_clock.h>
/*
* Clock ticks since initialization
*/
volatile rtems_unsigned32 Clock_driver_ticks;
/*
* This is the value programmed into the count down timer.
*/
rtems_unsigned32 Clock_Decrementer_value;
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_minor_number rtems_clock_minor;
void clockOff(void* unused)
{
/*
* Nothing to do as we cannot disable all interrupts and
* the decrementer interrupt enable is MSR_EE
*/
}
void clockOn(void* unused)
{
PPC_Set_decrementer( Clock_Decrementer_value );
}
/*
* Clock_isr
*
* This is the clock tick interrupt handler.
*
* Input parameters:
* vector - vector number
*
* Output parameters: NONE
*
* Return values: NONE
*
*/
void clockIsr()
{
/*
* The driver has seen another tick.
*/
PPC_Set_decrementer( Clock_Decrementer_value );
Clock_driver_ticks += 1;
/*
* Real Time Clock counter/timer is set to automatically reload.
*/
rtems_clock_tick();
}
int clockIsOn(void* unused)
{
unsigned32 msr_value;
_CPU_MSR_GET( msr_value );
if (msr_value & MSR_EE) return 1;
return 0;
}
/*
* Clock_exit
*
* This routine allows the clock driver to exit by masking the interrupt and
* disabling the clock's counter.
*
* Input parameters: NONE
*
* Output parameters: NONE
*
* Return values: NONE
*
*/
void Clock_exit( void )
{
(void) BSP_disconnect_clock_handler ();
}
/*
* Clock_initialize
*
* This routine initializes the clock driver.
*
* Input parameters:
* major - clock device major number
* minor - clock device minor number
* parg - pointer to optional device driver arguments
*
* Output parameters: NONE
*
* Return values:
* rtems_device_driver status code
*/
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)*
(BSP_Configuration.microseconds_per_tick/1000);
if (!BSP_connect_clock_handler ()) {
printk("Unable to initialize system clock\n");
rtems_fatal_error_occurred(1);
}
/* make major/minor avail to others such as shared memory driver */
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
} /* Clock_initialize */
/*
* Clock_control
*
* This routine is the clock device driver control entry point.
*
* Input parameters:
* major - clock device major number
* minor - clock device minor number
* parg - pointer to optional device driver arguments
*
* Output parameters: NONE
*
* Return values:
* rtems_device_driver status code
*/
rtems_device_driver Clock_control(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
rtems_libio_ioctl_args_t *args = pargp;
if (args == 0)
goto done;
Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)*
(BSP_Configuration.microseconds_per_tick/1000);
if (args->command == rtems_build_name('I', 'S', 'R', ' '))
clockIsr();
else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
{
if (!BSP_connect_clock_handler ()) {
printk("Error installing clock interrupt handler!\n");
rtems_fatal_error_occurred(1);
}
}
done:
return RTEMS_SUCCESSFUL;
}
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