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/* clock.c
*
* This routine initializes the PIT on the MPC8xx.
* The tick frequency is specified by the bsp.
*
* 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.com/license/LICENSE.
*/
#include <rtems.h>
#include <rtems/clockdrv.h>
#include <rtems/libio.h>
#include <rtems/powerpc/powerpc.h>
#include <stdlib.h> /* for atexit() */
#include <mpc8xx.h>
volatile uint32_t Clock_driver_ticks;
extern volatile m8xx_t m8xx;
extern int BSP_get_clock_irq_level(void);
extern int BSP_connect_clock_handler(rtems_isr_entry);
extern int BSP_disconnect_clock_handler(void);
extern uint32_t bsp_clicks_per_usec;
extern uint32_t bsp_clock_speed;
void Clock_exit( void );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_minor_number rtems_clock_minor;
/*
* ISR Handler
*/
rtems_isr Clock_isr(rtems_vector_number vector)
{
m8xx.piscr |= M8xx_PISCR_PS;
Clock_driver_ticks++;
rtems_clock_tick();
}
void clockOn(void* unused)
{
unsigned desiredLevel;
uint32_t pit_value;
uint32_t extclk;
bool force_prescaler = false;
uint32_t immr_val;
if (bsp_clicks_per_usec == 0) {
/*
* oscclk is too low for PIT, compute extclk and derive PIT from there
*/
/*
* determine external input clock by examining the PLL settings
* this must be done differently depending on type of PLL
*/
_mfspr(immr_val,M8xx_IMMR);
if (8 == ((immr_val & 0x0000FF00) >> 8)) {
/*
* for MPC866: complex PLL
*/
uint32_t plprcr_val;
uint32_t mfn_value;
uint32_t mfd_value;
uint32_t mfi_value;
uint32_t pdf_value;
uint32_t s_value;
plprcr_val = m8xx.plprcr;
mfn_value = (plprcr_val & (0xf8000000)) >> (31- 4);
mfd_value = (plprcr_val & (0x07c00000)) >> (31- 9);
s_value = (plprcr_val & (0x00300000)) >> (31-11);
mfi_value = (plprcr_val & (0x000f0000)) >> (31-15);
pdf_value = (plprcr_val & (0x00000006)) >> (31-30);
extclk = (((uint64_t)bsp_clock_speed)
* ((pdf_value + 1) * (mfd_value + 1))
/ (mfi_value * (mfd_value + 1) + mfn_value)
* (1 << s_value));
}
else {
/*
* for MPC860/850 etc: simple PLL
*/
uint32_t mf_value;
mf_value = m8xx.plprcr >> 20;
extclk = bsp_clock_speed / (mf_value+1);
}
pit_value = (extclk
/ 1000
/ 4
* rtems_configuration_get_microseconds_per_tick()
/ 1000);
m8xx.sccr |= (1<<23);
force_prescaler = true;
}
else {
pit_value = (rtems_configuration_get_microseconds_per_tick() *
bsp_clicks_per_usec);
m8xx.sccr &= ~(1<<23);
}
if ((pit_value > 0xffff) || force_prescaler){
/*
* try to activate prescaler
* NOTE: divider generates odd values now...
*/
pit_value = pit_value / 128;
m8xx.sccr |= (1<<24);
}
else {
m8xx.sccr &= ~(1<<24);
}
if (pit_value > 0xffff) { /* pit is only 16 bits long */
rtems_fatal_error_occurred(-1);
}
m8xx.pitc = pit_value - 1;
desiredLevel = BSP_get_clock_irq_level();
/* set PIT irq level, enable PIT, PIT interrupts */
/* and clear int. status */
m8xx.piscr = M8xx_PISCR_PIRQ(desiredLevel) |
M8xx_PISCR_PTE | M8xx_PISCR_PS | M8xx_PISCR_PIE;
}
/*
* Called via atexit()
* Remove the clock interrupt handler by setting handler to NULL
*/
void
clockOff(void* unused)
{
/* disable PIT and PIT interrupts */
m8xx.piscr &= ~(M8xx_PISCR_PTE | M8xx_PISCR_PIE);
}
int clockIsOn(void* unused)
{
if (m8xx.piscr & M8xx_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 ();
}
void Install_clock(rtems_isr_entry clock_isr)
{
Clock_driver_ticks = 0;
BSP_connect_clock_handler (clock_isr);
atexit(Clock_exit);
}
void
ReInstall_clock(rtems_isr_entry new_clock_isr)
{
BSP_connect_clock_handler (new_clock_isr);
}
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
}
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