/* time.c: FRV arch-specific time handling
*
* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/m68k/kernel/time.c
*
* 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> /* CONFIG_HEARTBEAT */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/irq.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/timer-regs.h>
#include <asm/mb-regs.h>
#include <asm/mb86943a.h>
#include <asm/irq-routing.h>
#include <linux/timex.h>
#define TICK_SIZE (tick_nsec / 1000)
extern unsigned long wall_jiffies;
unsigned long __nongprelbss __clkin_clock_speed_HZ;
unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
unsigned long __nongprelbss __res_bus_clock_speed_HZ;
unsigned long __nongprelbss __sdram_clock_speed_HZ;
unsigned long __nongprelbss __core_bus_clock_speed_HZ;
unsigned long __nongprelbss __core_clock_speed_HZ;
unsigned long __nongprelbss __dsu_clock_speed_HZ;
unsigned long __nongprelbss __serial_clock_speed_HZ;
unsigned long __delay_loops_MHz;
static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
static struct irqaction timer_irq = {
timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE, "timer", NULL, NULL
};
static inline int set_rtc_mmss(unsigned long nowtime)
{
return -1;
}
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
{
/* last time the cmos clock got updated */
static long last_rtc_update = 0;
/*
* Here we are in the timer irq handler. We just have irqs locally
* disabled but we don't know if the timer_bh is running on the other
* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
* the irq version of write_lock because as just said we have irq
* locally disabled. -arca
*/
write_seqlock(&xtime_lock);
do_timer(regs);
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING, regs);
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() 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 (set_rtc_mmss(xtime.tv_sec) == 0)
last_rtc_update = xtime.tv_sec;
else
last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
}
#ifdef CONFIG_HEARTBEAT
static unsigned short n;
n++;
__set_LEDS(n);
#endif /* CONFIG_HEARTBEAT */
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
void time_divisor_init(void)
{
unsigned short base, pre, prediv;
/* set the scheduling timer going */
pre = 1;
prediv = 4;
base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
__set_TPRV(pre);
__set_TxCKSL_DATA(0, prediv);
__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
__set_TCSR_DATA(0, base & 0xff);
__set_TCSR_DATA(0, base >> 8);
}
void time_init(void)
{
unsigned int year, mon, day, hour, min, sec;
extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
/* FIX by dqg : Set to zero for platforms that don't have tod */
/* without this time is undefined and can overflow time_t, causing */
/* very stange errors */
year = 1980;
mon = day = 1;
hour = min = sec = 0;
arch_gettod (&year, &mon, &day, &hour, &min, &sec);
if ((year += 1900) < 1970)
year += 100;
xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
xtime.tv_nsec = 0;
/* install scheduling interrupt handler */
setup_irq(IRQ_CPU_TIMER0, &timer_irq);
time_divisor_init();
}
/*
* This version of gettimeofday has near microsecond resolution.
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long seq;
unsigned long usec, sec;
unsigned long max_ntp_tick;
do {
unsigned long lost;
seq = read_seqbegin(&xtime_lock);
usec = 0;
lost = jiffies - wall_jiffies;
/*
* If time_adjust is negative then NTP is slowing the clock
* so make sure not to go into next possible interval.
* Better to lose some accuracy than have time go backwards..
*/
if (unlikely(time_adjust < 0)) {
max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
usec = min(usec, max_ntp_tick);
if (lost)
usec += lost * max_ntp_tick;
}
else if (unlikely(lost))
usec += lost * (USEC_PER_SEC / 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 -= 0 * 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);
ntp_clear();
write_sequnlock_irq(&xtime_lock);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return jiffies_64 * (1000000000 / HZ);
}
