2 * linux/arch/arm/common/time-acorn.c
4 * Copyright (c) 1996-2000 Russell King.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 * 24-Sep-1996 RMK Created
12 * 10-Oct-1996 RMK Brought up to date with arch-sa110eval
13 * 04-Dec-1997 RMK Updated for new arch/arm/time.c
14 * 13=Jun-2004 DS Moved to arch/arm/common b/c shared w/CLPS7500
16 #include <linux/timex.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/irq.h>
21 #include <asm/hardware.h>
23 #include <asm/hardware/ioc.h>
25 #include <asm/mach/time.h>
27 unsigned long ioc_timer_gettimeoffset(void)
29 unsigned int count1, count2, status;
32 ioc_writeb (0, IOC_T0LATCH);
34 count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
36 status = ioc_readb(IOC_IRQREQA);
38 ioc_writeb (0, IOC_T0LATCH);
40 count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
43 if (count2 < count1) {
45 * We have not had an interrupt between reading count1
48 if (status & (1 << 5))
50 } else if (count2 > count1) {
52 * We have just had another interrupt between reading
58 offset = (LATCH - offset) * (tick_nsec / 1000);
59 return (offset + LATCH/2) / LATCH;
62 void __init ioctime_init(void)
64 ioc_writeb(LATCH & 255, IOC_T0LTCHL);
65 ioc_writeb(LATCH >> 8, IOC_T0LTCHH);
66 ioc_writeb(0, IOC_T0GO);
70 ioc_timer_interrupt(int irq, void *dev_id)
72 write_seqlock(&xtime_lock);
74 write_sequnlock(&xtime_lock);
78 static struct irqaction ioc_timer_irq = {
80 .flags = IRQF_DISABLED,
81 .handler = ioc_timer_interrupt
85 * Set up timer interrupt.
87 static void __init ioc_timer_init(void)
90 setup_irq(IRQ_TIMER, &ioc_timer_irq);
93 struct sys_timer ioc_timer = {
94 .init = ioc_timer_init,
95 .offset = ioc_timer_gettimeoffset,