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/*
* Carsten Langgaard, carstenl@mips.com
* Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* Setting up the clock on the MIPS boards.
*/
#include <linux/types.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/mc146818rtc.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
#include <asm/div64.h>
#include <asm/cpu.h>
#include <asm/time.h>
#include <asm/mc146818-time.h>
#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/prom.h>
unsigned long cpu_khz;
#if defined(CONFIG_MIPS_SEAD)
#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ5)
#else
#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5)
#endif
#if defined(CONFIG_MIPS_ATLAS)
static char display_string[] = " LINUX ON ATLAS ";
#endif
#if defined(CONFIG_MIPS_MALTA)
static char display_string[] = " LINUX ON MALTA ";
#endif
#if defined(CONFIG_MIPS_SEAD)
static char display_string[] = " LINUX ON SEAD ";
#endif
static unsigned int display_count = 0;
#define MAX_DISPLAY_COUNT (sizeof(display_string) - 8)
#define MIPS_CPU_TIMER_IRQ (NR_IRQS-1)
static unsigned int timer_tick_count=0;
void mips_timer_interrupt(struct pt_regs *regs)
{
if ((timer_tick_count++ % HZ) == 0) {
mips_display_message(&display_string[display_count++]);
if (display_count == MAX_DISPLAY_COUNT)
display_count = 0;
}
ll_timer_interrupt(MIPS_CPU_TIMER_IRQ, regs);
}
/*
* Estimate CPU frequency. Sets mips_counter_frequency as a side-effect
*/
static unsigned int __init estimate_cpu_frequency(void)
{
unsigned int prid = read_c0_prid() & 0xffff00;
unsigned int count;
#ifdef CONFIG_MIPS_SEAD
/*
* The SEAD board doesn't have a real time clock, so we can't
* really calculate the timer frequency
* For now we hardwire the SEAD board frequency to 12MHz.
*/
if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
(prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
count = 12000000;
else
count = 6000000;
#endif
#if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA)
unsigned int flags;
local_irq_save(flags);
/* Start counter exactly on falling edge of update flag */
while (CMOS_READ(RTC_REG_A) & RTC_UIP);
while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
/* Start r4k counter. */
write_c0_count(0);
/* Read counter exactly on falling edge of update flag */
while (CMOS_READ(RTC_REG_A) & RTC_UIP);
while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
count = read_c0_count();
/* restore interrupts */
local_irq_restore(flags);
#endif
mips_hpt_frequency = count;
if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
(prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
count *= 2;
count += 5000; /* round */
count -= count%10000;
return count;
}
unsigned long __init mips_rtc_get_time(void)
{
return mc146818_get_cmos_time();
}
void __init mips_time_init(void)
{
unsigned int est_freq, flags;
local_irq_save(flags);
#if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA)
/* Set Data mode - binary. */
CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
#endif
est_freq = estimate_cpu_frequency ();
printk("CPU frequency %d.%02d MHz\n", est_freq/1000000,
(est_freq%1000000)*100/1000000);
cpu_khz = est_freq / 1000;
local_irq_restore(flags);
}
void __init mips_timer_setup(struct irqaction *irq)
{
/* we are using the cpu counter for timer interrupts */
irq->handler = no_action; /* we use our own handler */
setup_irq(MIPS_CPU_TIMER_IRQ, irq);
/* to generate the first timer interrupt */
write_c0_compare (read_c0_count() + mips_hpt_frequency/HZ);
set_c0_status(ALLINTS);
}
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