mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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0cd61b68c3
Untested, but this should fix up the bulk of the totally mechanical issues, and should make the actual detail fixing easier. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
/*
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* linux/arch/arm/mach-imx/time.c
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*
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* Copyright (C) 2000-2001 Deep Blue Solutions
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* Copyright (C) 2002 Shane Nay (shane@minirl.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/time.h>
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#include <asm/hardware.h>
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#include <asm/io.h>
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#include <asm/leds.h>
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#include <asm/irq.h>
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#include <asm/mach/time.h>
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/* Use timer 1 as system timer */
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#define TIMER_BASE IMX_TIM1_BASE
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/*
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* Returns number of us since last clock interrupt. Note that interrupts
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* will have been disabled by do_gettimeoffset()
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*/
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static unsigned long imx_gettimeoffset(void)
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{
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unsigned long ticks;
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/*
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* Get the current number of ticks. Note that there is a race
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* condition between us reading the timer and checking for
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* an interrupt. We get around this by ensuring that the
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* counter has not reloaded between our two reads.
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*/
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ticks = IMX_TCN(TIMER_BASE);
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/*
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* Interrupt pending? If so, we've reloaded once already.
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*/
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if (IMX_TSTAT(TIMER_BASE) & TSTAT_COMP)
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ticks += LATCH;
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/*
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* Convert the ticks to usecs
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*/
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return (1000000 / CLK32) * ticks;
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}
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/*
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* IRQ handler for the timer
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*/
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static irqreturn_t
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imx_timer_interrupt(int irq, void *dev_id)
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{
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write_seqlock(&xtime_lock);
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/* clear the interrupt */
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if (IMX_TSTAT(TIMER_BASE))
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IMX_TSTAT(TIMER_BASE) = 0;
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timer_tick();
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write_sequnlock(&xtime_lock);
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return IRQ_HANDLED;
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}
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static struct irqaction imx_timer_irq = {
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.name = "i.MX Timer Tick",
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.flags = IRQF_DISABLED | IRQF_TIMER,
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.handler = imx_timer_interrupt,
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};
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/*
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* Set up timer interrupt, and return the current time in seconds.
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*/
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static void __init imx_timer_init(void)
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{
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/*
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* Initialise to a known state (all timers off, and timing reset)
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*/
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IMX_TCTL(TIMER_BASE) = 0;
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IMX_TPRER(TIMER_BASE) = 0;
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IMX_TCMP(TIMER_BASE) = LATCH - 1;
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IMX_TCTL(TIMER_BASE) = TCTL_CLK_32 | TCTL_IRQEN | TCTL_TEN;
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/*
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* Make irqs happen for the system timer
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*/
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setup_irq(TIM1_INT, &imx_timer_irq);
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}
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struct sys_timer imx_timer = {
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.init = imx_timer_init,
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.offset = imx_gettimeoffset,
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};
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