1/*
2 *  linux/arch/arm/mach-footbridge/dc21285-timer.c
3 *
4 *  Copyright (C) 1998 Russell King.
5 *  Copyright (C) 1998 Phil Blundell
6 */
7#include <linux/init.h>
8#include <linux/interrupt.h>
9#include <linux/irq.h>
10
11#include <asm/irq.h>
12
13#include <asm/hardware/dec21285.h>
14#include <asm/mach/time.h>
15
16#include "common.h"
17
18/*
19 * Footbridge timer 1 support.
20 */
21static unsigned long timer1_latch;
22
23static unsigned long timer1_gettimeoffset (void)
24{
25	unsigned long value = timer1_latch - *CSR_TIMER1_VALUE;
26
27	return ((tick_nsec / 1000) * value) / timer1_latch;
28}
29
30static irqreturn_t
31timer1_interrupt(int irq, void *dev_id)
32{
33	write_seqlock(&xtime_lock);
34
35	*CSR_TIMER1_CLR = 0;
36
37	timer_tick();
38
39	write_sequnlock(&xtime_lock);
40
41	return IRQ_HANDLED;
42}
43
44static struct irqaction footbridge_timer_irq = {
45	.name		= "Timer1 timer tick",
46	.handler	= timer1_interrupt,
47	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
48};
49
50/*
51 * Set up timer interrupt.
52 */
53static void __init footbridge_timer_init(void)
54{
55	timer1_latch = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
56
57	*CSR_TIMER1_CLR  = 0;
58	*CSR_TIMER1_LOAD = timer1_latch;
59	*CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16;
60
61	setup_irq(IRQ_TIMER1, &footbridge_timer_irq);
62
63	isa_rtc_init();
64}
65
66struct sys_timer footbridge_timer = {
67	.init		= footbridge_timer_init,
68	.offset		= timer1_gettimeoffset,
69};
70