2005-04-16 16:20:36 -06:00
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/*
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* linux/arch/arm/mach-sa1100/time.c
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*
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* Copyright (C) 1998 Deborah Wallach.
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* Twiddles (C) 1999 Hugo Fiennes <hugo@empeg.com>
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*
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* 2000/03/29 (C) Nicolas Pitre <nico@cam.org>
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* Rewritten: big cleanup, much simpler, better HZ accuracy.
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*
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*/
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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2006-07-01 15:32:38 -06:00
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#include <linux/irq.h>
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2005-04-16 16:20:36 -06:00
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#include <linux/timex.h>
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#include <linux/signal.h>
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2007-11-12 14:55:12 -07:00
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#include <linux/clocksource.h>
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2005-04-16 16:20:36 -06:00
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#include <asm/mach/time.h>
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#include <asm/hardware.h>
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#define RTC_DEF_DIVIDER (32768 - 1)
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#define RTC_DEF_TRIM 0
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static int sa1100_set_rtc(void)
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{
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unsigned long current_time = xtime.tv_sec;
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if (RTSR & RTSR_ALE) {
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/* make sure not to forward the clock over an alarm */
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unsigned long alarm = RTAR;
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if (current_time >= alarm && alarm >= RCNR)
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return -ERESTARTSYS;
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}
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RCNR = current_time;
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return 0;
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}
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2005-09-01 05:48:48 -06:00
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#ifdef CONFIG_NO_IDLE_HZ
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static unsigned long initial_match;
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static int match_posponed;
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#endif
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2005-04-16 16:20:36 -06:00
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static irqreturn_t
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2006-10-06 11:53:39 -06:00
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sa1100_timer_interrupt(int irq, void *dev_id)
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2005-04-16 16:20:36 -06:00
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{
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unsigned int next_match;
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2005-09-01 05:48:48 -06:00
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#ifdef CONFIG_NO_IDLE_HZ
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if (match_posponed) {
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match_posponed = 0;
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OSMR0 = initial_match;
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}
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#endif
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2005-09-01 05:48:47 -06:00
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/*
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* Loop until we get ahead of the free running timer.
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* This ensures an exact clock tick count and time accuracy.
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* Since IRQs are disabled at this point, coherence between
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* lost_ticks(updated in do_timer()) and the match reg value is
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* ensured, hence we can use do_gettimeofday() from interrupt
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* handlers.
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*/
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2005-04-16 16:20:36 -06:00
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do {
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timer_tick();
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2005-04-16 16:20:36 -06:00
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OSSR = OSSR_M0; /* Clear match on timer 0 */
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next_match = (OSMR0 += LATCH);
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} while ((signed long)(next_match - OSCR) <= 0);
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return IRQ_HANDLED;
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}
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static struct irqaction sa1100_timer_irq = {
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.name = "SA11xx Timer Tick",
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.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
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2005-06-26 10:06:36 -06:00
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.handler = sa1100_timer_interrupt,
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2005-04-16 16:20:36 -06:00
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};
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2007-11-12 14:55:12 -07:00
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static cycle_t sa1100_read_oscr(void)
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{
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return OSCR;
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}
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static struct clocksource cksrc_sa1100_oscr = {
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.name = "oscr",
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.rating = 200,
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.read = sa1100_read_oscr,
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.mask = CLOCKSOURCE_MASK(32),
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.shift = 20,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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2005-04-16 16:20:36 -06:00
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static void __init sa1100_timer_init(void)
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{
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2006-11-20 14:17:09 -07:00
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unsigned long flags;
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set_rtc = sa1100_set_rtc;
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2005-11-08 15:43:06 -07:00
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OIER = 0; /* disable any timer interrupts */
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2005-04-16 16:20:36 -06:00
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OSSR = 0xf; /* clear status on all timers */
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setup_irq(IRQ_OST0, &sa1100_timer_irq);
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2006-11-20 14:17:09 -07:00
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local_irq_save(flags);
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2005-11-08 15:43:06 -07:00
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OIER = OIER_E0; /* enable match on timer 0 to cause interrupts */
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2006-11-20 14:17:09 -07:00
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OSMR0 = OSCR + LATCH; /* set initial match */
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local_irq_restore(flags);
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2007-11-12 14:55:12 -07:00
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cksrc_sa1100_oscr.mult =
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clocksource_hz2mult(CLOCK_TICK_RATE, cksrc_sa1100_oscr.shift);
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clocksource_register(&cksrc_sa1100_oscr);
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2005-04-16 16:20:36 -06:00
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}
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2005-09-01 05:48:48 -06:00
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#ifdef CONFIG_NO_IDLE_HZ
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static int sa1100_dyn_tick_enable_disable(void)
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{
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/* nothing to do */
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return 0;
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}
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static void sa1100_dyn_tick_reprogram(unsigned long ticks)
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{
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if (ticks > 1) {
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initial_match = OSMR0;
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OSMR0 = initial_match + ticks * LATCH;
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match_posponed = 1;
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}
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}
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static irqreturn_t
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sa1100_dyn_tick_handler(int irq, void *dev_id)
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{
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if (match_posponed) {
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match_posponed = 0;
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OSMR0 = initial_match;
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if ((signed long)(initial_match - OSCR) <= 0)
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return sa1100_timer_interrupt(irq, dev_id);
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2005-09-01 05:48:48 -06:00
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}
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return IRQ_NONE;
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}
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static struct dyn_tick_timer sa1100_dyn_tick = {
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.enable = sa1100_dyn_tick_enable_disable,
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.disable = sa1100_dyn_tick_enable_disable,
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.reprogram = sa1100_dyn_tick_reprogram,
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.handler = sa1100_dyn_tick_handler,
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};
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#endif
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2005-04-16 16:20:36 -06:00
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#ifdef CONFIG_PM
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unsigned long osmr[4], oier;
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static void sa1100_timer_suspend(void)
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{
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osmr[0] = OSMR0;
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osmr[1] = OSMR1;
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osmr[2] = OSMR2;
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osmr[3] = OSMR3;
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oier = OIER;
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}
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static void sa1100_timer_resume(void)
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{
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OSSR = 0x0f;
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OSMR0 = osmr[0];
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OSMR1 = osmr[1];
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OSMR2 = osmr[2];
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OSMR3 = osmr[3];
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OIER = oier;
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/*
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* OSMR0 is the system timer: make sure OSCR is sufficiently behind
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*/
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OSCR = OSMR0 - LATCH;
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}
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#else
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#define sa1100_timer_suspend NULL
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#define sa1100_timer_resume NULL
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#endif
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struct sys_timer sa1100_timer = {
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.init = sa1100_timer_init,
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.suspend = sa1100_timer_suspend,
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.resume = sa1100_timer_resume,
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2005-09-01 05:48:48 -06:00
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#ifdef CONFIG_NO_IDLE_HZ
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.dyn_tick = &sa1100_dyn_tick,
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#endif
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2005-04-16 16:20:36 -06:00
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};
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