/*
* Copyright 2001 MontaVista Software Inc.
* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
* Copyright (c) 2003 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/config.h>
#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/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/cpu.h>
#include <asm/div64.h>
#include <asm/hardirq.h>
#include <asm/sections.h>
#include <asm/time.h>
/* This is for machines which generate the exact clock. */
#define USECS_PER_JIFFY (1000000/HZ)
#define USECS_PER_JIFFY_FRAC ((u32)((1000000ULL << 32) / HZ))
#define TICK_SIZE (tick_nsec / 1000)
u64 jiffies_64 = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
/*
* forward reference
*/
extern volatile unsigned long wall_jiffies;
spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
/*
* whether we emulate local_timer_interrupts for SMP machines.
*/
int emulate_local_timer_interrupt;
/*
* 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_get_time)(void) = null_rtc_get_time;
int (*rtc_set_time)(unsigned long) = null_rtc_set_time;
int (*rtc_set_mmss)(unsigned long);
/*
* This version of gettimeofday has microsecond resolution and better than
* microsecond precision on fast machines with cycle counter.
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long seq;
unsigned long usec, sec;
do {
seq = read_seqbegin(&xtime_lock);
usec = do_gettimeoffset();
{
unsigned long lost = jiffies - wall_jiffies;
if (lost)
usec += lost * (1000000 / HZ);
}
sec = xtime.tv_sec;
usec += (xtime.tv_nsec / 1000);
} while (read_seqretry(&xtime_lock, seq));
while (usec >= 1000000) {
usec -= 1000000;
sec++;
}
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
/*
* This is revolting. We need to set "xtime" correctly. However, the
* value in this location is the value at the most recent update of
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
nsec -= do_gettimeoffset() * NSEC_PER_USEC;
nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
write_sequnlock_irq(&xtime_lock);
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
/*
* Gettimeoffset routines. These routines returns the time duration
* since last timer interrupt in usecs.
*
* If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset.
* Otherwise use calibrate_gettimeoffset()
*
* If the CPU does not have counter register all, you can either supply
* your own gettimeoffset() routine, or use null_gettimeoffset() routines,
* which gives the same resolution as HZ.
*/
/* usecs per counter cycle, shifted to left by 32 bits */
static unsigned int sll32_usecs_per_cycle;
/* how many counter cycles in a jiffy */
static unsigned long cycles_per_jiffy;
/* Cycle counter value at the previous timer interrupt.. */
static unsigned int timerhi, timerlo;
/* expirelo is the count value for next CPU timer interrupt */
static unsigned int expirelo;
/* last time when xtime and rtc are sync'ed up */
static long last_rtc_update;
/* the function pointer to one of the gettimeoffset funcs*/
unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset;
unsigned long null_gettimeoffset(void)
{
return 0;
}
unsigned long fixed_rate_gettimeoffset(void)
{
u32 count;
unsigned long res;
/* Get last timer tick in absolute kernel time */
count = read_c0_count();
/* .. relative to previous jiffy (32 bits is enough) */
count -= timerlo;
__asm__("multu %1,%2"
: "=h" (res)
: "r" (count), "r" (sll32_usecs_per_cycle)
: "lo", "accum");
/*
* Due to possible jiffies inconsistencies, we need to check
* the result so that we'll get a timer that is monotonic.
*/
if (res >= USECS_PER_JIFFY)
res = USECS_PER_JIFFY - 1;
return res;
}
/*
* Cached "1/(clocks per usec) * 2^32" value.
* It has to be recalculated once each jiffy.
*/
static unsigned long cached_quotient;
/* Last jiffy when calibrate_divXX_gettimeoffset() was called. */
static unsigned long last_jiffies;
/*
* This is copied from dec/time.c:do_ioasic_gettimeoffset() by Maciej.
*/
unsigned long calibrate_div32_gettimeoffset(void)
{
u32 count;
unsigned long res, tmp;
unsigned long quotient;
tmp = jiffies;
quotient = cached_quotient;
if (last_jiffies != tmp) {
last_jiffies = tmp;
if (last_jiffies != 0) {
unsigned long r0;
do_div64_32(r0, timerhi, timerlo, tmp);
do_div64_32(quotient, USECS_PER_JIFFY,
USECS_PER_JIFFY_FRAC, r0);
cached_quotient = quotient;
}
}
/* Get last timer tick in absolute kernel time */
count = read_c0_count();
/* .. relative to previous jiffy (32 bits is enough) */
count -= timerlo;
__asm__("multu %1,%2"
: "=h" (res)
: "r" (count), "r" (quotient)
: "lo", "accum");
/*
* Due to possible jiffies inconsistencies, we need to check
* the result so that we'll get a timer that is monotonic.
*/
if (res >= USECS_PER_JIFFY)
res = USECS_PER_JIFFY - 1;
return res;
}
unsigned long calibrate_div64_gettimeoffset(void)
{
u32 count;
unsigned long res, tmp;
unsigned long quotient;
tmp = jiffies;
quotient = cached_quotient;
if (tmp && last_jiffies != tmp) {
last_jiffies = tmp;
__asm__(".set push\n\t"
".set noreorder\n\t"
".set noat\n\t"
".set mips3\n\t"
"lwu %0,%2\n\t"
"dsll32 $1,%1,0\n\t"
"or $1,$1,%0\n\t"
"ddivu $0,$1,%3\n\t"
"mflo $1\n\t"
"dsll32 %0,%4,0\n\t"
"nop\n\t"
"ddivu $0,%0,$1\n\t"
"mflo %0\n\t"
".set pop"
: "=&r" (quotient)
: "r" (timerhi), "m" (timerlo),
"r" (tmp), "r" (USECS_PER_JIFFY));
cached_quotient = quotient;
}
/* Get last timer tick in absolute kernel time */
count = read_c0_count();
/* .. relative to previous jiffy (32 bits is enough) */
count -= timerlo;
__asm__("multu %1,%2"
: "=h" (res)
: "r" (count), "r" (quotient)
: "lo", "accum");
/*
* Due to possible jiffies inconsistencies, we need to check
* the result so that we'll get a timer that is monotonic.
*/
if (res >= USECS_PER_JIFFY)
res = USECS_PER_JIFFY - 1;
return res;
}
/*
* 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, struct pt_regs *regs)
{
if (!user_mode(regs)) {
if (prof_buffer && current->pid) {
unsigned long pc = regs->cp0_epc;
pc -= (unsigned long) _stext;
pc >>= prof_shift;
/*
* Dont ignore out-of-bounds pc values silently,
* put them into the last histogram slot, so if
* present, they will show up as a sharp peak.
*/
if (pc > prof_len - 1)
pc = prof_len - 1;
atomic_inc((atomic_t *)&prof_buffer[pc]);
}
}
#ifdef CONFIG_SMP
/* in UP mode, update_process_times() is invoked by do_timer() */
update_process_times(user_mode(regs));
#endif
}
/*
* 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, struct pt_regs *regs)
{
if (cpu_has_counter) {
unsigned int count;
/* ack timer interrupt, and try to set next interrupt */
expirelo += cycles_per_jiffy;
write_c0_compare(expirelo);
count = read_c0_count();
/* check to see if we have missed any timer interrupts */
if ((count - expirelo) < 0x7fffffff) {
/* missed_timer_count++; */
expirelo = count + cycles_per_jiffy;
write_c0_compare(expirelo);
}
/* Update timerhi/timerlo for intra-jiffy calibration. */
timerhi += count < timerlo; /* Wrap around */
timerlo = count;
}
/*
* call the generic timer interrupt handling
*/
do_timer(regs);
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be
* called as close as possible to 500 ms before the new second starts.
*/
write_seqlock(&xtime_lock);
if ((time_status & STA_UNSYNC) == 0 &&
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_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);
/*
* If jiffies has overflowed in this timer_interrupt we must
* update the timer[hi]/[lo] to make fast gettimeoffset funcs
* quotient calc still valid. -arca
*/
if (!jiffies) {
timerhi = timerlo = 0;
}
#if !defined(CONFIG_SMP)
/*
* 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, regs);
#else /* CONFIG_SMP */
if (emulate_local_timer_interrupt) {
/*
* this is the place where we send out inter-process
* interrupts and let each CPU do its own profiling
* and process accouting.
*
* Obviously we need to call local_timer_interrupt() for
* the current CPU too.
*/
panic("Not implemented yet!!!");
}
#endif /* CONFIG_SMP */
return IRQ_HANDLED;
}
asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs)
{
irq_enter();
kstat_this_cpu.irqs[irq]++;
/* we keep interrupt disabled all the time */
timer_interrupt(irq, NULL, regs);
irq_exit();
}
asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs)
{
irq_enter();
kstat_this_cpu.irqs[irq]++;
/* we keep interrupt disabled all the time */
local_timer_interrupt(irq, NULL, regs);
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_counter_frequency
* (only needed if you intended to use fixed_rate_gettimeoffset
* or use cpu counter as timer interrupt source)
* 2) setup xtime based on rtc_get_time().
* 3) choose a appropriate gettimeoffset routine.
* 4) calculate a couple of cached variables for later usage
* 5) board_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);
void (*board_timer_setup)(struct irqaction *irq);
unsigned int mips_counter_frequency;
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = SA_INTERRUPT,
.name = "timer",
};
void __init time_init(void)
{
if (board_time_init)
board_time_init();
if (!rtc_set_mmss)
rtc_set_mmss = rtc_set_time;
xtime.tv_sec = rtc_get_time();
xtime.tv_nsec = 0;
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
/* choose appropriate gettimeoffset routine */
if (!cpu_has_counter) {
/* no cpu counter - sorry */
do_gettimeoffset = null_gettimeoffset;
} else if (mips_counter_frequency != 0) {
/* we have cpu counter and know counter frequency! */
do_gettimeoffset = fixed_rate_gettimeoffset;
} else if ((current_cpu_data.isa_level == MIPS_CPU_ISA_M32) ||
(current_cpu_data.isa_level == MIPS_CPU_ISA_I) ||
(current_cpu_data.isa_level == MIPS_CPU_ISA_II) ) {
/* we need to calibrate the counter but we don't have
* 64-bit division. */
do_gettimeoffset = calibrate_div32_gettimeoffset;
} else {
/* we need to calibrate the counter but we *do* have
* 64-bit division. */
do_gettimeoffset = calibrate_div64_gettimeoffset;
}
/* caclulate cache parameters */
if (mips_counter_frequency) {
cycles_per_jiffy = mips_counter_frequency / HZ;
/* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */
/* any better way to do this? */
sll32_usecs_per_cycle = mips_counter_frequency / 100000;
sll32_usecs_per_cycle = 0xffffffff / sll32_usecs_per_cycle;
sll32_usecs_per_cycle *= 10;
/*
* For those using cpu counter as timer, this sets up the
* first interrupt
*/
write_c0_compare(cycles_per_jiffy);
write_c0_count(0);
expirelo = cycles_per_jiffy;
}
/*
* Call board specific timer interrupt setup.
*
* this pointer must be setup in machine setup routine.
*
* Even if the machine choose to use 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.
*/
board_timer_setup(&timer_irqaction);
}
#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_set_time);
EXPORT_SYMBOL(rtc_get_time);
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