296 lines
8.1 KiB
C
296 lines
8.1 KiB
C
/*
|
|
* 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
|
|
|
|
unsigned long cpu_khz;
|
|
|
|
#if defined(CONFIG_MIPS_ATLAS)
|
|
static char display_string[] = " LINUX ON ATLAS ";
|
|
#endif
|
|
#if defined(CONFIG_MIPS_MALTA)
|
|
#if defined(CONFIG_MIPS_MT_SMTC)
|
|
static char display_string[] = " SMTC LINUX ON MALTA ";
|
|
#else
|
|
static char display_string[] = " LINUX ON MALTA ";
|
|
#endif /* CONFIG_MIPS_MT_SMTC */
|
|
#endif
|
|
#if defined(CONFIG_MIPS_SEAD)
|
|
static char display_string[] = " LINUX ON SEAD ";
|
|
#endif
|
|
static unsigned int display_count;
|
|
#define MAX_DISPLAY_COUNT (sizeof(display_string) - 8)
|
|
|
|
#define CPUCTR_IMASKBIT (0x100 << MIPSCPU_INT_CPUCTR)
|
|
|
|
static unsigned int timer_tick_count;
|
|
static int mips_cpu_timer_irq;
|
|
extern void smtc_timer_broadcast(int);
|
|
|
|
static inline void scroll_display_message(void)
|
|
{
|
|
if ((timer_tick_count++ % HZ) == 0) {
|
|
mips_display_message(&display_string[display_count++]);
|
|
if (display_count == MAX_DISPLAY_COUNT)
|
|
display_count = 0;
|
|
}
|
|
}
|
|
|
|
static void mips_timer_dispatch(void)
|
|
{
|
|
do_IRQ(mips_cpu_timer_irq);
|
|
}
|
|
|
|
/*
|
|
* Redeclare until I get around mopping the timer code insanity on MIPS.
|
|
*/
|
|
extern int null_perf_irq(void);
|
|
|
|
extern int (*perf_irq)(void);
|
|
|
|
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.
|
|
*/
|
|
|
|
int vpflags;
|
|
|
|
/*
|
|
* We could be here due to timer interrupt,
|
|
* perf counter overflow, or both.
|
|
*/
|
|
if (read_c0_cause() & (1 << 26))
|
|
perf_irq();
|
|
|
|
if (read_c0_cause() & (1 << 30)) {
|
|
/* If timer interrupt, make it de-assert */
|
|
write_c0_compare (read_c0_count() - 1);
|
|
/*
|
|
* DVPE is necessary so long as cross-VPE interrupts
|
|
* are done via read-modify-write of Cause register.
|
|
*/
|
|
vpflags = dvpe();
|
|
clear_c0_cause(CPUCTR_IMASKBIT);
|
|
evpe(vpflags);
|
|
/*
|
|
* 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);
|
|
smtc_timer_broadcast(cpu_data[cpu].vpe_id);
|
|
scroll_display_message();
|
|
} else {
|
|
write_c0_compare(read_c0_count() +
|
|
(mips_hpt_frequency/HZ));
|
|
local_timer_interrupt(irq, dev_id);
|
|
smtc_timer_broadcast(cpu_data[cpu].vpe_id);
|
|
}
|
|
}
|
|
#else /* CONFIG_MIPS_MT_SMTC */
|
|
int r2 = cpu_has_mips_r2;
|
|
|
|
if (cpu == 0) {
|
|
/*
|
|
* CPU 0 handles the global timer interrupt job and process
|
|
* accounting resets count/compare registers to trigger next
|
|
* timer int.
|
|
*/
|
|
if (!r2 || (read_c0_cause() & (1 << 26)))
|
|
if (perf_irq())
|
|
goto out;
|
|
|
|
/* we keep interrupt disabled all the time */
|
|
if (!r2 || (read_c0_cause() & (1 << 30)))
|
|
timer_interrupt(irq, NULL);
|
|
|
|
scroll_display_message();
|
|
} 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 __init mips_rtc_get_time(void)
|
|
{
|
|
return mc146818_get_cmos_time();
|
|
}
|
|
|
|
void __init mips_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;
|
|
}
|
|
|
|
void __init plat_timer_setup(struct irqaction *irq)
|
|
{
|
|
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 (cpu_has_vint)
|
|
set_vi_handler (MIPSCPU_INT_CPUCTR, mips_timer_dispatch);
|
|
mips_cpu_timer_irq = MIPSCPU_INT_BASE + MIPSCPU_INT_CPUCTR;
|
|
}
|
|
|
|
|
|
/* 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, CPUCTR_IMASKBIT);
|
|
#else
|
|
setup_irq(mips_cpu_timer_irq, irq);
|
|
#endif /* CONFIG_MIPS_MT_SMTC */
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* irq_desc(riptor) is a global resource, when the interrupt overlaps
|
|
on seperate cpu's the first one tries to handle the second interrupt.
|
|
The effect is that the int remains disabled on the second cpu.
|
|
Mark the interrupt with IRQ_PER_CPU to avoid any confusion */
|
|
irq_desc[mips_cpu_timer_irq].status |= IRQ_PER_CPU;
|
|
#endif
|
|
|
|
/* to generate the first timer interrupt */
|
|
write_c0_compare (read_c0_count() + mips_hpt_frequency/HZ);
|
|
}
|