Root/arch/arm/mach-clps711x/time.c

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#include <linux/io.h>
25
26#include <mach/hardware.h>
27#include <asm/irq.h>
28#include <asm/leds.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    timer_tick();
54    return IRQ_HANDLED;
55}
56
57static struct irqaction clps711x_timer_irq = {
58    .name = "CLPS711x Timer Tick",
59    .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
60    .handler = p720t_timer_interrupt,
61};
62
63static void __init clps711x_timer_init(void)
64{
65    struct timespec tv;
66    unsigned int syscon;
67
68    syscon = clps_readl(SYSCON1);
69    syscon |= SYSCON1_TC2S | SYSCON1_TC2M;
70    clps_writel(syscon, SYSCON1);
71
72    clps_writel(LATCH-1, TC2D); /* 512kHz / 100Hz - 1 */
73
74    setup_irq(IRQ_TC2OI, &clps711x_timer_irq);
75
76    tv.tv_nsec = 0;
77    tv.tv_sec = clps_readl(RTCDR);
78    do_settimeofday(&tv);
79}
80
81struct sys_timer clps711x_timer = {
82    .init = clps711x_timer_init,
83    .offset = clps711x_gettimeoffset,
84};
85

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