LXR linux/arch/arm/mach-footbridge/dc21285-timer.c

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