blob: 581fca934bb3e73adb055bcb2d7caff9aef978f9 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/common/time-acorn.c
3 *
4 * Copyright (c) 1996-2000 Russell King.
5 *
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.
9 *
10 * Changelog:
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
15 */
16#include <linux/timex.h>
17#include <linux/init.h>
18#include <linux/interrupt.h>
Thomas Gleixnerc4bfa282006-07-01 22:32:14 +010019#include <linux/irq.h>
Russell Kingfced80c2008-09-06 12:10:45 +010020#include <linux/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Russell Kinga09e64f2008-08-05 16:14:15 +010022#include <mach/hardware.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <asm/hardware/ioc.h>
24
25#include <asm/mach/time.h>
26
27unsigned long ioc_timer_gettimeoffset(void)
28{
29 unsigned int count1, count2, status;
30 long offset;
31
32 ioc_writeb (0, IOC_T0LATCH);
33 barrier ();
34 count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
35 barrier ();
36 status = ioc_readb(IOC_IRQREQA);
37 barrier ();
38 ioc_writeb (0, IOC_T0LATCH);
39 barrier ();
40 count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
41
42 offset = count2;
43 if (count2 < count1) {
44 /*
45 * We have not had an interrupt between reading count1
46 * and count2.
47 */
48 if (status & (1 << 5))
49 offset -= LATCH;
50 } else if (count2 > count1) {
51 /*
52 * We have just had another interrupt between reading
53 * count1 and count2.
54 */
55 offset -= LATCH;
56 }
57
58 offset = (LATCH - offset) * (tick_nsec / 1000);
59 return (offset + LATCH/2) / LATCH;
60}
61
62void __init ioctime_init(void)
63{
64 ioc_writeb(LATCH & 255, IOC_T0LTCHL);
65 ioc_writeb(LATCH >> 8, IOC_T0LTCHH);
66 ioc_writeb(0, IOC_T0GO);
67}
68
69static irqreturn_t
Linus Torvalds0cd61b62006-10-06 10:53:39 -070070ioc_timer_interrupt(int irq, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -070071{
Linus Torvalds0cd61b62006-10-06 10:53:39 -070072 timer_tick();
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 return IRQ_HANDLED;
74}
75
76static struct irqaction ioc_timer_irq = {
77 .name = "timer",
Thomas Gleixner52e405e2006-07-03 02:20:05 +020078 .flags = IRQF_DISABLED,
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 .handler = ioc_timer_interrupt
80};
81
82/*
83 * Set up timer interrupt.
84 */
85static void __init ioc_timer_init(void)
86{
87 ioctime_init();
Russell King927b6c42012-03-01 16:55:44 +000088 setup_irq(IRQ_TIMER0, &ioc_timer_irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089}
90
91struct sys_timer ioc_timer = {
92 .init = ioc_timer_init,
93 .offset = ioc_timer_gettimeoffset,
94};
95