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/*
* This routine initializes the PIT on the MPC5xx.
* The tick frequency is specified by the BSP.
*/
/*
* MPC5xx port sponsored by Defence Research and Development Canada - Suffield
* Copyright (C) 2004, Real-Time Systems Inc. (querbach@realtime.bc.ca)
*
* Derived from c/src/lib/libcpu/powerpc/mpc8xx/clock/clock.c:
*
* Author: Jay Monkman (jmonkman@frasca.com)
* Copyright (C) 1998 by Frasca International, Inc.
*
* Derived from c/src/lib/libcpu/ppc/ppc403/clock/clock.c:
*
* Author: Andrew Bray <andy@i-cubed.co.uk>
*
* COPYRIGHT (c) 1995 by i-cubed ltd.
*
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of i-cubed limited not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* i-cubed limited makes no representations about the suitability
* of this software for any purpose.
*
* Derived from c/src/lib/libcpu/hppa1_1/clock/clock.c:
*
* COPYRIGHT (c) 1989-2007.
* 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 <rtems.h>
#include <rtems/clockdrv.h>
#include <rtems/libio.h>
#include <libcpu/irq.h>
#include <stdlib.h> /* for atexit() */
#include <mpc5xx.h>
volatile uint32_t Clock_driver_ticks;
extern int BSP_connect_clock_handler(rtems_isr_entry);
extern int BSP_disconnect_clock_handler(void);
extern uint32_t bsp_clicks_per_usec;
void Clock_exit( void );
/*
* ISR Handler
*/
rtems_isr Clock_isr(rtems_vector_number vector)
{
usiu.piscrk = USIU_UNLOCK_KEY;
usiu.piscr |= USIU_PISCR_PS; /* acknowledge interrupt */
usiu.piscrk = 0;
Clock_driver_ticks++;
rtems_clock_tick();
}
void clockOn(void* unused)
{
unsigned desiredLevel;
uint32_t pit_value;
/* calculate and set modulus */
pit_value = (rtems_configuration_get_microseconds_per_tick() *
bsp_clicks_per_usec) - 1 ;
if (pit_value > 0xffff) { /* pit is only 16 bits long */
rtems_fatal_error_occurred(-1);
}
usiu.sccrk = USIU_UNLOCK_KEY;
usiu.sccr &= ~USIU_SCCR_RTDIV; /* RTC and PIT clock is divided by 4 */
usiu.sccrk = 0;
usiu.pitck = USIU_UNLOCK_KEY;
usiu.pitc = pit_value;
usiu.pitck = 0;
/* set PIT irq level, enable PIT, PIT interrupts */
/* and clear int. status */
desiredLevel = CPU_irq_level_from_symbolic_name(CPU_PERIODIC_TIMER);
usiu.piscrk = USIU_UNLOCK_KEY;
usiu.piscr = USIU_PISCR_PIRQ(desiredLevel) /* set interrupt priority */
| USIU_PISCR_PS /* acknowledge interrupt */
| USIU_PISCR_PIE /* enable interrupt */
| USIU_PISCR_PITF /* freeze during debug */
| USIU_PISCR_PTE; /* enable timer */
usiu.piscrk = 0;
}
void clockOff(void* unused)
{
/* disable PIT and PIT interrupts */
usiu.piscrk = USIU_UNLOCK_KEY;
usiu.piscr &= ~(USIU_PISCR_PTE | USIU_PISCR_PIE);
usiu.piscrk = 0;
}
int clockIsOn(void* unused)
{
if (usiu.piscr & USIU_PISCR_PIE)
return 1;
return 0;
}
/*
* Called via atexit()
* Remove the clock interrupt handler by setting handler to NULL
*/
void Clock_exit(void)
{
(void) BSP_disconnect_clock_handler ();
}
static void Install_clock(rtems_isr_entry clock_isr)
{
Clock_driver_ticks = 0;
BSP_connect_clock_handler (clock_isr);
atexit(Clock_exit);
}
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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