diff options
Diffstat (limited to 'arch/frv/kernel/time.c')
| -rw-r--r-- | arch/frv/kernel/time.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/arch/frv/kernel/time.c b/arch/frv/kernel/time.c new file mode 100644 index 000000000000..075db6644694 --- /dev/null +++ b/arch/frv/kernel/time.c @@ -0,0 +1,234 @@ +/* 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; + +u64 jiffies_64 = INITIAL_JIFFIES; +EXPORT_SYMBOL(jiffies_64); + +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 ((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 (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; +} + +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); + + 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); + clock_was_set(); + return 0; +} + +/* + * Scheduler clock - returns current time in nanosec units. + */ +unsigned long long sched_clock(void) +{ + return jiffies_64 * (1000000000 / HZ); +} |