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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [mips/] [kernel/] [time.c] - Blame information for rev 3

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1 3 xianfeng 
/*
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 * Copyright 2001 MontaVista Software Inc.
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 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
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 * Copyright (c) 2003, 2004  Maciej W. Rozycki
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 *
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 * Common time service routines for MIPS machines.
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 *
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 * This program is free software; you can redistribute  it and/or modify it
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 * under  the terms of  the GNU General  Public License as published by the
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 * Free Software Foundation;  either version 2 of the  License, or (at your
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 * option) any later version.
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 */
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#include <linux/bug.h>
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#include <linux/clockchips.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/param.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <linux/smp.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <asm/cpu-features.h>
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#include <asm/div64.h>
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#include <asm/smtc_ipi.h>
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#include <asm/time.h>
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/*
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 * forward reference
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 */
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL(rtc_lock);
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int __weak rtc_mips_set_time(unsigned long sec)
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{
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        return 0;
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}
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EXPORT_SYMBOL(rtc_mips_set_time);
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int __weak rtc_mips_set_mmss(unsigned long nowtime)
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{
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        return rtc_mips_set_time(nowtime);
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}
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int update_persistent_clock(struct timespec now)
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{
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        return rtc_mips_set_mmss(now.tv_sec);
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}
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int (*mips_timer_state)(void);
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int null_perf_irq(void)
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{
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        return 0;
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}
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EXPORT_SYMBOL(null_perf_irq);
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int (*perf_irq)(void) = null_perf_irq;
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EXPORT_SYMBOL(perf_irq);
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/*
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 * time_init() - it does the following things.
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 *
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 * 1) plat_time_init() -
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 *      a) (optional) set up RTC routines,
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 *      b) (optional) calibrate and set the mips_hpt_frequency
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 *          (only needed if you intended to use cpu counter as timer interrupt
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 *           source)
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 * 2) calculate a couple of cached variables for later usage
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 */
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unsigned int mips_hpt_frequency;
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void __init clocksource_set_clock(struct clocksource *cs, unsigned int clock)
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{
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        u64 temp;
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        u32 shift;
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        /* Find a shift value */
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        for (shift = 32; shift > 0; shift--) {
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                temp = (u64) NSEC_PER_SEC << shift;
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                do_div(temp, clock);
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                if ((temp >> 32) == 0)
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                        break;
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        }
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        cs->shift = shift;
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        cs->mult = (u32) temp;
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}
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void __cpuinit clockevent_set_clock(struct clock_event_device *cd,
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        unsigned int clock)
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{
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        u64 temp;
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        u32 shift;
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        /* Find a shift value */
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        for (shift = 32; shift > 0; shift--) {
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                temp = (u64) clock << shift;
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                do_div(temp, NSEC_PER_SEC);
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                if ((temp >> 32) == 0)
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                        break;
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        }
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        cd->shift = shift;
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        cd->mult = (u32) temp;
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}
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/*
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 * This function exists in order to cause an error due to a duplicate
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 * definition if platform code should have its own implementation.  The hook
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 * to use instead is plat_time_init.  plat_time_init does not receive the
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 * irqaction pointer argument anymore.  This is because any function which
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 * initializes an interrupt timer now takes care of its own request_irq rsp.
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 * setup_irq calls and each clock_event_device should use its own
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 * struct irqrequest.
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 */
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void __init plat_timer_setup(void)
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{
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        BUG();
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}
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static __init int cpu_has_mfc0_count_bug(void)
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{
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        switch (current_cpu_type()) {
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        case CPU_R4000PC:
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        case CPU_R4000SC:
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        case CPU_R4000MC:
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                /*
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                 * V3.0 is documented as suffering from the mfc0 from count bug.
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                 * Afaik this is the last version of the R4000.  Later versions
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                 * were marketed as R4400.
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                 */
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                return 1;
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        case CPU_R4400PC:
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        case CPU_R4400SC:
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        case CPU_R4400MC:
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                /*
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                 * The published errata for the R4400 upto 3.0 say the CPU
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                 * has the mfc0 from count bug.
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                 */
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                if ((current_cpu_data.processor_id & 0xff) <= 0x30)
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                        return 1;
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                /*
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                 * we assume newer revisions are ok
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                 */
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                return 0;
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        }
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        return 0;
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}
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void __init time_init(void)
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{
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        plat_time_init();
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        if (mips_clockevent_init() || !cpu_has_mfc0_count_bug())
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                init_mips_clocksource();
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}

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