/* 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, IRQF_DISABLED, 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); }