LXR linux/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