62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/arch/ia64/sn/kernel/sn2/timer.c
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*
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* Copyright (C) 2003 Silicon Graphics, Inc.
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* Copyright (C) 2003 Hewlett-Packard Co
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* David Mosberger <davidm@hpl.hp.com>: updated for new timer-interpolation infrastructure
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/time.h>
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#include <linux/interrupt.h>
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#include <linux/clocksource.h>
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#include <asm/hw_irq.h>
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#include <asm/timex.h>
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#include <asm/sn/leds.h>
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#include <asm/sn/shub_mmr.h>
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#include <asm/sn/clksupport.h>
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extern unsigned long sn_rtc_cycles_per_second;
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static u64 read_sn2(struct clocksource *cs)
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{
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return (u64)readq(RTC_COUNTER_ADDR);
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}
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static struct clocksource clocksource_sn2 = {
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.name = "sn2_rtc",
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.rating = 450,
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.read = read_sn2,
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.mask = (1LL << 55) - 1,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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/*
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* sn udelay uses the RTC instead of the ITC because the ITC is not
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* synchronized across all CPUs, and the thread may migrate to another CPU
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* if preemption is enabled.
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*/
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static void
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ia64_sn_udelay (unsigned long usecs)
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{
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unsigned long start = rtc_time();
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unsigned long end = start +
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usecs * sn_rtc_cycles_per_second / 1000000;
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while (time_before((unsigned long)rtc_time(), end))
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cpu_relax();
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}
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void __init sn_timer_init(void)
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{
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clocksource_sn2.archdata.fsys_mmio = RTC_COUNTER_ADDR;
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clocksource_register_hz(&clocksource_sn2, sn_rtc_cycles_per_second);
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ia64_udelay = &ia64_sn_udelay;
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}
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