/*
* 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/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/mipsmtregs.h>
#include <asm/hardirq.h>
#include <asm/irq.h>
#include <asm/div64.h>
#include <asm/cpu.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/prom.h>
#ifdef CONFIG_MIPS_ATLAS
#include <asm/mips-boards/atlasint.h>
#endif
#ifdef CONFIG_MIPS_MALTA
#include <asm/mips-boards/maltaint.h>
#endif
#ifdef CONFIG_MIPS_SEAD
#include <asm/mips-boards/seadint.h>
#endif
unsigned long cpu_khz;
static int mips_cpu_timer_irq;
extern int cp0_perfcount_irq;
extern void smtc_timer_broadcast(void);
static void mips_timer_dispatch(void)
{
do_IRQ(mips_cpu_timer_irq);
}
static void mips_perf_dispatch(void)
{
do_IRQ(cp0_perfcount_irq);
}
/*
* Redeclare until I get around mopping the timer code insanity on MIPS.
*/
extern int null_perf_irq(void);
extern int (*perf_irq)(void);
/*
* Possibly handle a performance counter interrupt.
* Return true if the timer interrupt should not be checked
*/
static inline int handle_perf_irq (int r2)
{
/*
* The performance counter overflow interrupt may be shared with the
* timer interrupt (cp0_perfcount_irq < 0). If it is and a
* performance counter has overflowed (perf_irq() == IRQ_HANDLED)
* and we can't reliably determine if a counter interrupt has also
* happened (!r2) then don't check for a timer interrupt.
*/
return (cp0_perfcount_irq < 0) &&
perf_irq() == IRQ_HANDLED &&
!r2;
}
irqreturn_t mips_timer_interrupt(int irq, void *dev_id)
{
int cpu = smp_processor_id();
#ifdef CONFIG_MIPS_MT_SMTC
/*
* In an SMTC system, one Count/Compare set exists per VPE.
* Which TC within a VPE gets the interrupt is essentially
* random - we only know that it shouldn't be one with
* IXMT set. Whichever TC gets the interrupt needs to
* send special interprocessor interrupts to the other
* TCs to make sure that they schedule, etc.
*
* That code is specific to the SMTC kernel, not to
* the a particular platform, so it's invoked from
* the general MIPS timer_interrupt routine.
*/
/*
* We could be here due to timer interrupt,
* perf counter overflow, or both.
*/
(void) handle_perf_irq(1);
if (read_c0_cause() & (1 << 30)) {
/*
* There are things we only want to do once per tick
* in an "MP" system. One TC of each VPE will take
* the actual timer interrupt. The others will get
* timer broadcast IPIs. We use whoever it is that takes
* the tick on VPE 0 to run the full timer_interrupt().
*/
if (cpu_data[cpu].vpe_id == 0) {
timer_interrupt(irq, NULL);
} else {
write_c0_compare(read_c0_count() +
(mips_hpt_frequency/HZ));
local_timer_interrupt(irq, dev_id);
}
smtc_timer_broadcast();
}
#else /* CONFIG_MIPS_MT_SMTC */
int r2 = cpu_has_mips_r2;
if (handle_perf_irq(r2))
goto out;
if (r2 && ((read_c0_cause() & (1 << 30)) == 0))
goto out;
if (cpu == 0) {
/*
* CPU 0 handles the global timer interrupt job and process
* accounting resets count/compare registers to trigger next
* timer int.
*/
timer_interrupt(irq, NULL);
} else {
/* Everyone else needs to reset the timer int here as
ll_local_timer_interrupt doesn't */
/*
* FIXME: need to cope with counter underflow.
* More support needs to be added to kernel/time for
* counter/timer interrupts on multiple CPU's
*/
write_c0_compare(read_c0_count() + (mips_hpt_frequency/HZ));
/*
* Other CPUs should do profiling and process accounting
*/
local_timer_interrupt(irq, dev_id);
}
out:
#endif /* CONFIG_MIPS_MT_SMTC */
return IRQ_HANDLED;
}
/*
* Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect
*/
static unsigned int __init estimate_cpu_frequency(void)
{
unsigned int prid = read_c0_prid() & 0xffff00;
unsigned int count;
#if defined(CONFIG_MIPS_SEAD) || defined(CONFIG_MIPS_SIM)
/*
* 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 long flags;
unsigned int start;
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. */
start = read_c0_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() - start;
/* 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 read_persistent_clock(void)
{
return mc146818_get_cmos_time();
}
void __init plat_time_init(void)
{
unsigned int est_freq;
/* Set Data mode - binary. */
CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
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;
mips_scroll_message();
}
irqreturn_t mips_perf_interrupt(int irq, void *dev_id)
{
return perf_irq();
}
static struct irqaction perf_irqaction = {
.handler = mips_perf_interrupt,
.flags = IRQF_DISABLED | IRQF_PERCPU,
.name = "performance",
};
void __init plat_perf_setup(struct irqaction *irq)
{
cp0_perfcount_irq = -1;
#ifdef MSC01E_INT_BASE
if (cpu_has_veic) {
set_vi_handler (MSC01E_INT_PERFCTR, mips_perf_dispatch);
cp0_perfcount_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
} else
#endif
if (cp0_perfcount_irq >= 0) {
if (cpu_has_vint)
set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
#ifdef CONFIG_MIPS_MT_SMTC
setup_irq_smtc(cp0_perfcount_irq, irq,
0x100 << cp0_perfcount_irq);
#else
setup_irq(cp0_perfcount_irq, irq);
#endif /* CONFIG_MIPS_MT_SMTC */
#ifdef CONFIG_SMP
set_irq_handler(cp0_perfcount_irq, handle_percpu_irq);
#endif
}
}
void __init plat_timer_setup(struct irqaction *irq)
{
#ifdef MSC01E_INT_BASE
if (cpu_has_veic) {
set_vi_handler (MSC01E_INT_CPUCTR, mips_timer_dispatch);
mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
}
else
#endif
{
if (cpu_has_vint)
set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
}
/* we are using the cpu counter for timer interrupts */
irq->handler = mips_timer_interrupt; /* we use our own handler */
#ifdef CONFIG_MIPS_MT_SMTC
setup_irq_smtc(mips_cpu_timer_irq, irq, 0x100 << cp0_compare_irq);
#else
setup_irq(mips_cpu_timer_irq, irq);
#endif /* CONFIG_MIPS_MT_SMTC */
#ifdef CONFIG_SMP
set_irq_handler(mips_cpu_timer_irq, handle_percpu_irq);
#endif
plat_perf_setup(&perf_irqaction);
}
