109 lines
2.5 KiB
C
109 lines
2.5 KiB
C
/*
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* arch/arm/mach-iop3xx/iop321-time.c
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*
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* Timer code for IOP321 based systems
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*
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* Author: Deepak Saxena <dsaxena@mvista.com>
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*
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* Copyright 2002-2003 MontaVista Software Inc.
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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/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/timex.h>
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#include <asm/hardware.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <asm/uaccess.h>
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#include <asm/mach/irq.h>
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#include <asm/mach/time.h>
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#define IOP321_TIME_SYNC 0
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static inline unsigned long get_elapsed(void)
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{
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return LATCH - *IOP321_TU_TCR0;
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}
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static unsigned long iop321_gettimeoffset(void)
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{
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unsigned long elapsed, usec;
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u32 tisr1, tisr2;
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/*
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* If an interrupt was pending before we read the timer,
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* we've already wrapped. Factor this into the time.
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* If an interrupt was pending after we read the timer,
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* it may have wrapped between checking the interrupt
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* status and reading the timer. Re-read the timer to
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* be sure its value is after the wrap.
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*/
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asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr1));
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elapsed = get_elapsed();
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asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr2));
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if(tisr1 & 1)
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elapsed += LATCH;
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else if (tisr2 & 1)
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elapsed = LATCH + get_elapsed();
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/*
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* Now convert them to usec.
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*/
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usec = (unsigned long)(elapsed / (CLOCK_TICK_RATE/1000000));
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return usec;
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}
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static irqreturn_t
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iop321_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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{
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u32 tisr;
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write_seqlock(&xtime_lock);
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asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr));
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tisr |= 1;
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asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (tisr));
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timer_tick(regs);
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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 iop321_timer_irq = {
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.name = "IOP321 Timer Tick",
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.handler = iop321_timer_interrupt,
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.flags = SA_INTERRUPT | SA_TIMER,
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};
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static void __init iop321_timer_init(void)
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{
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u32 timer_ctl;
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setup_irq(IRQ_IOP321_TIMER0, &iop321_timer_irq);
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timer_ctl = IOP321_TMR_EN | IOP321_TMR_PRIVILEGED | IOP321_TMR_RELOAD |
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IOP321_TMR_RATIO_1_1;
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asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (LATCH));
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asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
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}
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struct sys_timer iop321_timer = {
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.init = &iop321_timer_init,
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.offset = iop321_gettimeoffset,
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};
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