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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/i8253.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/irqchip/mips-gic.h>
#include <linux/timex.h>
#include <linux/mc146818rtc.h>
#include <asm/cpu.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#include <asm/hardirq.h>
#include <asm/irq.h>
#include <asm/div64.h>
#include <asm/setup.h>
#include <asm/time.h>
#include <asm/mc146818-time.h>
#include <asm/msc01_ic.h>
#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/maltaint.h>
static int mips_cpu_timer_irq;
static int mips_cpu_perf_irq;
extern int cp0_perfcount_irq;
static unsigned int gic_frequency;
static void mips_timer_dispatch(void)
{
do_IRQ(mips_cpu_timer_irq);
}
static void mips_perf_dispatch(void)
{
do_IRQ(mips_cpu_perf_irq);
}
static unsigned int freqround(unsigned int freq, unsigned int amount)
{
freq += amount;
freq -= freq % (amount*2);
return freq;
}
/*
* Estimate CPU and GIC frequencies.
*/
static void __init estimate_frequencies(void)
{
unsigned long flags;
unsigned int count, start;
cycle_t giccount = 0, gicstart = 0;
#if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
return;
#endif
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));
/* Initialize counters. */
start = read_c0_count();
if (gic_present) {
gic_start_count();
gicstart = gic_read_count();
}
/* 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();
if (gic_present)
giccount = gic_read_count();
local_irq_restore(flags);
count -= start;
mips_hpt_frequency = count;
if (gic_present) {
giccount -= gicstart;
gic_frequency = giccount;
}
}
void read_persistent_clock(struct timespec *ts)
{
ts->tv_sec = mc146818_get_cmos_time();
ts->tv_nsec = 0;
}
int get_c0_fdc_int(void)
{
/*
* Some cores claim the FDC is routable through the GIC, but it doesn't
* actually seem to be connected for those Malta bitstreams.
*/
switch (current_cpu_type()) {
case CPU_INTERAPTIV:
case CPU_PROAPTIV:
return -1;
};
if (cpu_has_veic)
return -1;
else if (gic_present)
return gic_get_c0_fdc_int();
else if (cp0_fdc_irq >= 0)
return MIPS_CPU_IRQ_BASE + cp0_fdc_irq;
else
return -1;
}
int get_c0_perfcount_int(void)
{
if (cpu_has_veic) {
set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
} else if (gic_present) {
mips_cpu_perf_irq = gic_get_c0_perfcount_int();
} else if (cp0_perfcount_irq >= 0) {
mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
} else {
mips_cpu_perf_irq = -1;
}
return mips_cpu_perf_irq;
}
unsigned int get_c0_compare_int(void)
{
if (cpu_has_veic) {
set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
} else if (gic_present) {
mips_cpu_timer_irq = gic_get_c0_compare_int();
} else {
mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
}
return mips_cpu_timer_irq;
}
static void __init init_rtc(void)
{
unsigned char freq, ctrl;
/* Set 32KHz time base if not already set */
freq = CMOS_READ(RTC_FREQ_SELECT);
if ((freq & RTC_DIV_CTL) != RTC_REF_CLCK_32KHZ)
CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
/* Ensure SET bit is clear so RTC can run */
ctrl = CMOS_READ(RTC_CONTROL);
if (ctrl & RTC_SET)
CMOS_WRITE(ctrl & ~RTC_SET, RTC_CONTROL);
}
void __init plat_time_init(void)
{
unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
unsigned int freq;
init_rtc();
estimate_frequencies();
freq = mips_hpt_frequency;
if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
(prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
freq *= 2;
freq = freqround(freq, 5000);
printk("CPU frequency %d.%02d MHz\n", freq/1000000,
(freq%1000000)*100/1000000);
mips_scroll_message();
#ifdef CONFIG_I8253
/* Only Malta has a PIT. */
setup_pit_timer();
#endif
#ifdef CONFIG_MIPS_GIC
if (gic_present) {
freq = freqround(gic_frequency, 5000);
printk("GIC frequency %d.%02d MHz\n", freq/1000000,
(freq%1000000)*100/1000000);
#ifdef CONFIG_CLKSRC_MIPS_GIC
gic_clocksource_init(gic_frequency);
#endif
}
#endif
}
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