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- /*
- * arch/arm/mach-ns9xxx/time.c
- *
- * Copyright (C) 2006 by Digi International Inc.
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
- #include <linux/jiffies.h>
- #include <linux/interrupt.h>
- #include <linux/irq.h>
- #include <asm/arch-ns9xxx/regs-sys.h>
- #include <asm/arch-ns9xxx/clock.h>
- #include <asm/arch-ns9xxx/irqs.h>
- #include <asm/arch/system.h>
- #include "generic.h"
- #define TIMERCLOCKSELECT 64
- static u32 usecs_per_tick;
- static irqreturn_t
- ns9xxx_timer_interrupt(int irq, void *dev_id)
- {
- write_seqlock(&xtime_lock);
- timer_tick();
- write_sequnlock(&xtime_lock);
- return IRQ_HANDLED;
- }
- static unsigned long ns9xxx_timer_gettimeoffset(void)
- {
- /* return the microseconds which have passed since the last interrupt
- * was _serviced_. That is, if an interrupt is pending or the counter
- * reloads, return one periode more. */
- u32 counter1 = SYS_TR(0);
- int pending = SYS_ISR & (1 << IRQ_TIMER0);
- u32 counter2 = SYS_TR(0);
- u32 elapsed;
- if (pending || counter2 > counter1)
- elapsed = 2 * SYS_TRC(0) - counter2;
- else
- elapsed = SYS_TRC(0) - counter1;
- return (elapsed * usecs_per_tick) >> 16;
- }
- static struct irqaction ns9xxx_timer_irq = {
- .name = "NS9xxx Timer Tick",
- .flags = IRQF_DISABLED | IRQF_TIMER,
- .handler = ns9xxx_timer_interrupt,
- };
- static void __init ns9xxx_timer_init(void)
- {
- int tc;
- usecs_per_tick =
- SH_DIV(1000000 * TIMERCLOCKSELECT, ns9xxx_cpuclock(), 16);
- /* disable timer */
- if ((tc = SYS_TC(0)) & SYS_TCx_TEN)
- SYS_TC(0) = tc & ~SYS_TCx_TEN;
- SYS_TRC(0) = SH_DIV(ns9xxx_cpuclock(), (TIMERCLOCKSELECT * HZ), 0);
- REGSET(tc, SYS_TCx, TEN, EN);
- REGSET(tc, SYS_TCx, TLCS, DIV64); /* This must match TIMERCLOCKSELECT */
- REGSET(tc, SYS_TCx, INTS, EN);
- REGSET(tc, SYS_TCx, UDS, DOWN);
- REGSET(tc, SYS_TCx, TDBG, STOP);
- REGSET(tc, SYS_TCx, TSZ, 32);
- REGSET(tc, SYS_TCx, REN, EN);
- SYS_TC(0) = tc;
- setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq);
- }
- struct sys_timer ns9xxx_timer = {
- .init = ns9xxx_timer_init,
- .offset = ns9xxx_timer_gettimeoffset,
- };
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