![Alexey Dobriyan](/assets/img/avatar_default.png)
Use attribute(weak). Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
205 lines
4.6 KiB
C
205 lines
4.6 KiB
C
/*
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* arch/xtensa/kernel/time.c
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*
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* Timer and clock support.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2005 Tensilica Inc.
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*
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* Chris Zankel <chris@zankel.net>
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*/
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/profile.h>
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#include <linux/delay.h>
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#include <asm/timex.h>
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#include <asm/platform.h>
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL(rtc_lock);
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#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
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unsigned long ccount_per_jiffy; /* per 1/HZ */
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unsigned long ccount_nsec; /* nsec per ccount increment */
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#endif
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unsigned int last_ccount_stamp;
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static long last_rtc_update = 0;
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static irqreturn_t timer_interrupt(int irq, void *dev_id);
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static struct irqaction timer_irqaction = {
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.handler = timer_interrupt,
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.flags = IRQF_DISABLED,
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.name = "timer",
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};
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void __init time_init(void)
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{
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time_t sec_o, sec_n = 0;
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/* The platform must provide a function to calibrate the processor
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* speed for the CALIBRATE.
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*/
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#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
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printk("Calibrating CPU frequency ");
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platform_calibrate_ccount();
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printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
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(int)(ccount_per_jiffy/(10000/HZ))%100);
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#endif
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/* Set time from RTC (if provided) */
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if (platform_get_rtc_time(&sec_o) == 0)
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while (platform_get_rtc_time(&sec_n))
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if (sec_o != sec_n)
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break;
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xtime.tv_nsec = 0;
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last_rtc_update = xtime.tv_sec = sec_n;
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last_ccount_stamp = get_ccount();
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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/* Initialize the linux timer interrupt. */
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setup_irq(LINUX_TIMER_INT, &timer_irqaction);
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set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
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}
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int do_settimeofday(struct timespec *tv)
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{
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time_t wtm_sec, sec = tv->tv_sec;
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long wtm_nsec, nsec = tv->tv_nsec;
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unsigned long ccount;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irq(&xtime_lock);
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/* This is revolting. We need to set "xtime" correctly. However, the
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* value in this location is the value at the most recent update of
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* wall time. Discover what correction gettimeofday() would have
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* made, and then undo it!
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*/
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ccount = get_ccount();
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nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC;
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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set_normalized_timespec(&xtime, sec, nsec);
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set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
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ntp_clear();
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write_sequnlock_irq(&xtime_lock);
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return 0;
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}
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EXPORT_SYMBOL(do_settimeofday);
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void do_gettimeofday(struct timeval *tv)
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{
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unsigned long flags;
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unsigned long sec, usec, delta, seq;
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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delta = get_ccount() - last_ccount_stamp;
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sec = xtime.tv_sec;
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usec = (xtime.tv_nsec / NSEC_PER_USEC);
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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usec += (delta * CCOUNT_NSEC) / NSEC_PER_USEC;
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for (; usec >= 1000000; sec++, usec -= 1000000)
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;
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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}
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EXPORT_SYMBOL(do_gettimeofday);
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/*
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* The timer interrupt is called HZ times per second.
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*/
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irqreturn_t timer_interrupt (int irq, void *dev_id)
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{
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unsigned long next;
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next = get_linux_timer();
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again:
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while ((signed long)(get_ccount() - next) > 0) {
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profile_tick(CPU_PROFILING);
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#ifndef CONFIG_SMP
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update_process_times(user_mode(get_irq_regs()));
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#endif
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write_seqlock(&xtime_lock);
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last_ccount_stamp = next;
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next += CCOUNT_PER_JIFFY;
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do_timer (1); /* Linux handler in kernel/timer.c */
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if (ntp_synced() &&
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xtime.tv_sec - last_rtc_update >= 659 &&
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abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ) {
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if (platform_set_rtc_time(xtime.tv_sec+1) == 0)
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last_rtc_update = xtime.tv_sec+1;
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else
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/* Do it again in 60 s */
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last_rtc_update += 60;
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}
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write_sequnlock(&xtime_lock);
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}
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/* NOTE: writing CCOMPAREn clears the interrupt. */
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set_linux_timer (next);
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/* Make sure we didn't miss any tick... */
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if ((signed long)(get_ccount() - next) > 0)
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goto again;
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/* Allow platform to do something useful (Wdog). */
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platform_heartbeat();
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return IRQ_HANDLED;
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}
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#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
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void __devinit calibrate_delay(void)
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{
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loops_per_jiffy = CCOUNT_PER_JIFFY;
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printk("Calibrating delay loop (skipped)... "
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"%lu.%02lu BogoMIPS preset\n",
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loops_per_jiffy/(1000000/HZ),
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(loops_per_jiffy/(10000/HZ)) % 100);
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}
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#endif
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