LXR linux-old/arch/m68k/hp300/time.c

   1/*
   2 *  linux/arch/m68k/hp300/time.c
   3 *
   4 *  Copyright (C) 1998 Philip Blundell <philb@gnu.org>
   5 *
   6 *  This file contains the HP300-specific time handling code.
   7 */
   8
   9#include <asm/ptrace.h>
  10#include <linux/types.h>
  11#include <linux/init.h>
  12#include <linux/sched.h>
  13#include <linux/kernel_stat.h>
  14#include <linux/interrupt.h>
  15#include <asm/machdep.h>
  16#include <asm/irq.h>
  17#include <asm/io.h>
  18#include <asm/system.h>
  19#include <asm/traps.h>
  20#include "ints.h"
  21
  22/* Clock hardware definitions */
  23
  24#define CLOCKBASE       0xf05f8000
  25
  26#define CLKCR1          0x1
  27#define CLKCR2          0x3
  28#define CLKCR3          CLKCR1
  29#define CLKSR           CLKCR2
  30#define CLKMSB1         0x5
  31#define CLKMSB2         0x9
  32#define CLKMSB3         0xD
  33
  34/* This is for machines which generate the exact clock. */
  35#define USECS_PER_JIFFY (1000000/HZ)
  36
  37#define INTVAL ((10000 / 4) - 1)
  38
  39static void hp300_tick(int irq, void *dev_id, struct pt_regs *regs)
  40{
  41  unsigned long tmp;
  42  void (*vector)(int, void *, struct pt_regs *) = dev_id;
  43  in_8(CLOCKBASE + CLKSR);
  44  asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
  45  vector(irq, NULL, regs);
  46}
  47
  48unsigned long hp300_gettimeoffset(void)
  49{
  50  /* Read current timer 1 value */
  51  unsigned char lsb, msb1, msb2;
  52  unsigned short ticks;
  53
  54  msb1 = in_8(CLOCKBASE + 5);
  55  lsb = in_8(CLOCKBASE + 7);
  56  msb2 = in_8(CLOCKBASE + 5);
  57  if (msb1 != msb2)
  58    /* A carry happened while we were reading.  Read it again */
  59    lsb = in_8(CLOCKBASE + 7);
  60  ticks = INTVAL - ((msb2 << 8) | lsb);
  61  return (USECS_PER_JIFFY * ticks) / INTVAL;
  62}
  63
  64void __init hp300_sched_init(void (*vector)(int, void *, struct pt_regs *))
  65{
  66  out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  67  out_8(CLOCKBASE + CLKCR1, 0x1);               /* reset */
  68
  69  asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
  70
  71  sys_request_irq(6, hp300_tick, IRQ_FLG_STD, "timer tick", vector);
  72
  73  out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  74  out_8(CLOCKBASE + CLKCR1, 0x40);              /* enable irq */
  75}
  76