/*
* Copyright 2001 MontaVista Software Inc.
* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
* Copyright (c) 2003, 2004 Maciej W. Rozycki
*
* Common time service routines for MIPS machines. See
* Documentation/mips/time.README.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/bootinfo.h>
#include <asm/cache.h>
#include <asm/compiler.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm/div64.h>
#include <asm/sections.h>
#include <asm/time.h>
/*
* The integer part of the number of usecs per jiffy is taken from tick,
* but the fractional part is not recorded, so we calculate it using the
* initial value of HZ. This aids systems where tick isn't really an
* integer (e.g. for HZ = 128).
*/
#define USECS_PER_JIFFY TICK_SIZE
#define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ))
#define TICK_SIZE (tick_nsec / 1000)
/*
* forward reference
*/
DEFINE_SPINLOCK(rtc_lock);
/*
* By default we provide the null RTC ops
*/
static unsigned long null_rtc_get_time(void)
{
return mktime(2000, 1, 1, 0, 0, 0);
}
static int null_rtc_set_time(unsigned long sec)
{
return 0;
}
unsigned long (*rtc_mips_get_time)(void) = null_rtc_get_time;
int (*rtc_mips_set_time)(unsigned long) = null_rtc_set_time;
int (*rtc_mips_set_mmss)(unsigned long);
/* how many counter cycles in a jiffy */
static unsigned long cycles_per_jiffy __read_mostly;
/* expirelo is the count value for next CPU timer interrupt */
static unsigned int expirelo;
/*
* Null timer ack for systems not needing one (e.g. i8254).
*/
static void null_timer_ack(void) { /* nothing */ }
/*
* Null high precision timer functions for systems lacking one.
*/
static cycle_t null_hpt_read(void)
{
return 0;
}
/*
* Timer ack for an R4k-compatible timer of a known frequency.
*/
static void c0_timer_ack(void)
{
unsigned int count;
/* Ack this timer interrupt and set the next one. */
expirelo += cycles_per_jiffy;
write_c0_compare(expirelo);
/* Check to see if we have missed any timer interrupts. */
while (((count = read_c0_count()) - expirelo) < 0x7fffffff) {
/* missed_timer_count++; */
expirelo = count + cycles_per_jiffy;
write_c0_compare(expirelo);
}
}
/*
* High precision timer functions for a R4k-compatible timer.
*/
static cycle_t c0_hpt_read(void)
{
return read_c0_count();
}
/* For use both as a high precision timer and an interrupt source. */
static void __init c0_hpt_timer_init(void)
{
expirelo = read_c0_count() + cycles_per_jiffy;
write_c0_compare(expirelo);
}
int (*mips_timer_state)(void);
void (*mips_timer_ack)(void);
/* last time when xtime and rtc are sync'ed up */
static long last_rtc_update;
/*
* local_timer_interrupt() does profiling and process accounting
* on a per-CPU basis.
*
* In UP mode, it is invoked from the (global) timer_interrupt.
*
* In SMP mode, it might invoked by per-CPU timer interrupt, or
* a broadcasted inter-processor interrupt which itself is triggered
* by the global timer interrupt.
*/
void local_timer_interrupt(int irq, void *dev_id)
{
profile_tick(CPU_PROFILING);
update_process_times(user_mode(get_irq_regs()));
}
/*
* High-level timer interrupt service routines. This function
* is set as irqaction->handler and is invoked through do_IRQ.
*/
irqreturn_t timer_interrupt(int irq, void *dev_id)
{
write_seqlock(&xtime_lock);
mips_timer_ack();
/*
* call the generic timer interrupt handling
*/
do_timer(1);
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be
* called as close as possible to 500 ms before the new second starts.
*/
if (ntp_synced() &&
xtime.tv_sec > last_rtc_update + 660 &&
(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
if (rtc_mips_set_mmss(xtime.tv_sec) == 0) {
last_rtc_update = xtime.tv_sec;
} else {
/* do it again in 60 s */
last_rtc_update = xtime.tv_sec - 600;
}
}
write_sequnlock(&xtime_lock);
/*
* In UP mode, we call local_timer_interrupt() to do profiling
* and process accouting.
*
* In SMP mode, local_timer_interrupt() is invoked by appropriate
* low-level local timer interrupt handler.
*/
local_timer_interrupt(irq, dev_id);
return IRQ_HANDLED;
}
int null_perf_irq(void)
{
return 0;
}
int (*perf_irq)(void) = null_perf_irq;
EXPORT_SYMBOL(null_perf_irq);
EXPORT_SYMBOL(perf_irq);
/*
* Timer interrupt
*/
int cp0_compare_irq;
/*
* Performance counter IRQ or -1 if shared with timer
*/
int cp0_perfcount_irq;
EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
/*
* 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;
}
asmlinkage void ll_timer_interrupt(int irq)
{
int r2 = cpu_has_mips_r2;
irq_enter();
kstat_this_cpu.irqs[irq]++;
if (handle_perf_irq(r2))
goto out;
if (r2 && ((read_c0_cause() & (1 << 30)) == 0))
goto out;
timer_interrupt(irq, NULL);
out:
irq_exit();
}
asmlinkage void ll_local_timer_interrupt(int irq)
{
irq_enter();
if (smp_processor_id() != 0)
kstat_this_cpu.irqs[irq]++;
/* we keep interrupt disabled all the time */
local_timer_interrupt(irq, NULL);
irq_exit();
}
/*
* time_init() - it does the following things.
*
* 1) board_time_init() -
* a) (optional) set up RTC routines,
* b) (optional) calibrate and set the mips_hpt_frequency
* (only needed if you intended to use cpu counter as timer interrupt
* source)
* 2) setup xtime based on rtc_mips_get_time().
* 3) calculate a couple of cached variables for later usage
* 4) plat_timer_setup() -
* a) (optional) over-write any choices made above by time_init().
* b) machine specific code should setup the timer irqaction.
* c) enable the timer interrupt
*/
void (*board_time_init)(void);
unsigned int mips_hpt_frequency;
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = IRQF_DISABLED | IRQF_PERCPU,
.name = "timer",
};
static unsigned int __init calibrate_hpt(void)
{
cycle_t frequency, hpt_start, hpt_end, hpt_count, hz;
const int loops = HZ / 10;
int log_2_loops = 0;
int i;
/*
* We want to calibrate for 0.1s, but to avoid a 64-bit
* division we round the number of loops up to the nearest
* power of 2.
*/
while (loops > 1 << log_2_loops)
log_2_loops++;
i = 1 << log_2_loops;
/*
* Wait for a rising edge of the timer interrupt.
*/
while (mips_timer_state());
while (!mips_timer_state());
/*
* Now see how many high precision timer ticks happen
* during the calculated number of periods between timer
* interrupts.
*/
hpt_start = clocksource_mips.read();
do {
while (mips_timer_state());
while (!mips_timer_state());
} while (--i);
hpt_end = clocksource_mips.read();
hpt_count = (hpt_end - hpt_start) & clocksource_mips.mask;
hz = HZ;
frequency = hpt_count * hz;
return frequency >> log_2_loops;
}
struct clocksource clocksource_mips = {
.name = "MIPS",
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init init_mips_clocksource(void)
{
u64 temp;
u32 shift;
if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
return;
/* Calclate a somewhat reasonable rating value */
clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
/* Find a shift value */
for (shift = 32; shift > 0; shift--) {
temp = (u64) NSEC_PER_SEC << shift;
do_div(temp, mips_hpt_frequency);
if ((temp >> 32) == 0)
break;
}
clocksource_mips.shift = shift;
clocksource_mips.mult = (u32)temp;
clocksource_register(&clocksource_mips);
}
void __init time_init(void)
{
if (board_time_init)
board_time_init();
if (!rtc_mips_set_mmss)
rtc_mips_set_mmss = rtc_mips_set_time;
xtime.tv_sec = rtc_mips_get_time();
xtime.tv_nsec = 0;
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
/* Choose appropriate high precision timer routines. */
if (!cpu_has_counter && !clocksource_mips.read)
/* No high precision timer -- sorry. */
clocksource_mips.read = null_hpt_read;
else if (!mips_hpt_frequency && !mips_timer_state) {
/* A high precision timer of unknown frequency. */
if (!clocksource_mips.read)
/* No external high precision timer -- use R4k. */
clocksource_mips.read = c0_hpt_read;
} else {
/* We know counter frequency. Or we can get it. */
if (!clocksource_mips.read) {
/* No external high precision timer -- use R4k. */
clocksource_mips.read = c0_hpt_read;
if (!mips_timer_state) {
/* No external timer interrupt -- use R4k. */
mips_timer_ack = c0_timer_ack;
/* Calculate cache parameters. */
cycles_per_jiffy =
(mips_hpt_frequency + HZ / 2) / HZ;
/*
* This sets up the high precision
* timer for the first interrupt.
*/
c0_hpt_timer_init();
}
}
if (!mips_hpt_frequency)
mips_hpt_frequency = calibrate_hpt();
/* Report the high precision timer rate for a reference. */
printk("Using %u.%03u MHz high precision timer.\n",
((mips_hpt_frequency + 500) / 1000) / 1000,
((mips_hpt_frequency + 500) / 1000) % 1000);
}
if (!mips_timer_ack)
/* No timer interrupt ack (e.g. i8254). */
mips_timer_ack = null_timer_ack;
/*
* Call board specific timer interrupt setup.
*
* this pointer must be setup in machine setup routine.
*
* Even if a machine chooses to use a low-level timer interrupt,
* it still needs to setup the timer_irqaction.
* In that case, it might be better to set timer_irqaction.handler
* to be NULL function so that we are sure the high-level code
* is not invoked accidentally.
*/
plat_timer_setup(&timer_irqaction);
init_mips_clocksource();
}
#define FEBRUARY 2
#define STARTOFTIME 1970
#define SECDAY 86400L
#define SECYR (SECDAY * 365)
#define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400))
#define days_in_year(y) (leapyear(y) ? 366 : 365)
#define days_in_month(m) (month_days[(m) - 1])
static int month_days[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
void to_tm(unsigned long tim, struct rtc_time *tm)
{
long hms, day, gday;
int i;
gday = day = tim / SECDAY;
hms = tim % SECDAY;
/* Hours, minutes, seconds are easy */
tm->tm_hour = hms / 3600;
tm->tm_min = (hms % 3600) / 60;
tm->tm_sec = (hms % 3600) % 60;
/* Number of years in days */
for (i = STARTOFTIME; day >= days_in_year(i); i++)
day -= days_in_year(i);
tm->tm_year = i;
/* Number of months in days left */
if (leapyear(tm->tm_year))
days_in_month(FEBRUARY) = 29;
for (i = 1; day >= days_in_month(i); i++)
day -= days_in_month(i);
days_in_month(FEBRUARY) = 28;
tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */
/* Days are what is left over (+1) from all that. */
tm->tm_mday = day + 1;
/*
* Determine the day of week
*/
tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */
}
EXPORT_SYMBOL(rtc_lock);
EXPORT_SYMBOL(to_tm);
EXPORT_SYMBOL(rtc_mips_set_time);
EXPORT_SYMBOL(rtc_mips_get_time);
