2 * arch/arm/mach-ns9xxx/time.c
4 * Copyright (C) 2006 by Digi International Inc.
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
11 #include <linux/jiffies.h>
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
14 #include <asm/arch-ns9xxx/regs-sys.h>
15 #include <asm/arch-ns9xxx/clock.h>
16 #include <asm/arch-ns9xxx/irqs.h>
17 #include <asm/arch/system.h>
20 #define TIMERCLOCKSELECT 64
22 static u32 usecs_per_tick;
25 ns9xxx_timer_interrupt(int irq, void *dev_id)
27 int timerno = irq - IRQ_TIMER0;
30 write_seqlock(&xtime_lock);
32 write_sequnlock(&xtime_lock);
36 if (REGGET(tc, SYS_TCx, REN) == SYS_TCx_REN_DIS) {
37 REGSET(tc, SYS_TCx, TEN, DIS);
40 REGSET(tc, SYS_TCx, INTC, SET);
42 REGSET(tc, SYS_TCx, INTC, UNSET);
48 static unsigned long ns9xxx_timer_gettimeoffset(void)
50 /* return the microseconds which have passed since the last interrupt
51 * was _serviced_. That is, if an interrupt is pending or the counter
52 * reloads, return one period more. */
54 u32 counter1 = SYS_TR(0);
55 int pending = SYS_ISR & (1 << IRQ_TIMER0);
56 u32 counter2 = SYS_TR(0);
59 if (pending || counter2 > counter1)
60 elapsed = 2 * SYS_TRC(0) - counter2;
62 elapsed = SYS_TRC(0) - counter1;
64 return (elapsed * usecs_per_tick) >> 16;
68 static struct irqaction ns9xxx_timer_irq = {
69 .name = "NS9xxx Timer Tick",
70 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
71 .handler = ns9xxx_timer_interrupt,
74 static void __init ns9xxx_timer_init(void)
79 SH_DIV(1000000 * TIMERCLOCKSELECT, ns9xxx_cpuclock(), 16);
82 if ((tc = SYS_TC(0)) & SYS_TCx_TEN)
83 SYS_TC(0) = tc & ~SYS_TCx_TEN;
85 SYS_TRC(0) = SH_DIV(ns9xxx_cpuclock(), (TIMERCLOCKSELECT * HZ), 0);
87 REGSET(tc, SYS_TCx, TEN, EN);
88 REGSET(tc, SYS_TCx, TLCS, DIV64); /* This must match TIMERCLOCKSELECT */
89 REGSET(tc, SYS_TCx, INTS, EN);
90 REGSET(tc, SYS_TCx, UDS, DOWN);
91 REGSET(tc, SYS_TCx, TDBG, STOP);
92 REGSET(tc, SYS_TCx, TSZ, 32);
93 REGSET(tc, SYS_TCx, REN, EN);
96 setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq);
99 struct sys_timer ns9xxx_timer = {
100 .init = ns9xxx_timer_init,
101 .offset = ns9xxx_timer_gettimeoffset,