1/*
2 *  linux/arch/arm/mach-clps711x/time.c
3 *
4 *  Copyright (C) 2001 Deep Blue Solutions Ltd.
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 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18 */
19#include <linux/timex.h>
20#include <linux/init.h>
21#include <linux/interrupt.h>
22#include <linux/irq.h>
23#include <linux/sched.h>
24
25#include <asm/hardware.h>
26#include <asm/irq.h>
27#include <asm/leds.h>
28#include <asm/io.h>
29#include <asm/hardware/clps7111.h>
30
31#include <asm/mach/time.h>
32
33
34/*
35 * gettimeoffset() returns time since last timer tick, in usecs.
36 *
37 * 'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy.
38 * 'tick' is usecs per jiffy.
39 */
40static unsigned long clps711x_gettimeoffset(void)
41{
42	unsigned long hwticks;
43	hwticks = LATCH - (clps_readl(TC2D) & 0xffff);	/* since last underflow */
44	return (hwticks * (tick_nsec / 1000)) / LATCH;
45}
46
47/*
48 * IRQ handler for the timer
49 */
50static irqreturn_t
51p720t_timer_interrupt(int irq, void *dev_id)
52{
53	write_seqlock(&xtime_lock);
54	timer_tick();
55	write_sequnlock(&xtime_lock);
56	return IRQ_HANDLED;
57}
58
59static struct irqaction clps711x_timer_irq = {
60	.name		= "CLPS711x Timer Tick",
61	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
62	.handler	= p720t_timer_interrupt,
63};
64
65static void __init clps711x_timer_init(void)
66{
67	struct timespec tv;
68	unsigned int syscon;
69
70	syscon = clps_readl(SYSCON1);
71	syscon |= SYSCON1_TC2S | SYSCON1_TC2M;
72	clps_writel(syscon, SYSCON1);
73
74	clps_writel(LATCH-1, TC2D); /* 512kHz / 100Hz - 1 */
75
76	setup_irq(IRQ_TC2OI, &clps711x_timer_irq);
77
78	tv.tv_nsec = 0;
79	tv.tv_sec = clps_readl(RTCDR);
80	do_settimeofday(&tv);
81}
82
83struct sys_timer clps711x_timer = {
84	.init		= clps711x_timer_init,
85	.offset		= clps711x_gettimeoffset,
86};
87