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 <asm/blinken.h>
  21 #include "ints.h"
  22
  23 /* Clock hardware definitions */
  24
  25 #define CLOCKBASE       0xf05f8000
  26
  27 #define CLKCR1          0x1
  28 #define CLKCR2          0x3
  29 #define CLKCR3          CLKCR1
  30 #define CLKSR           CLKCR2
  31 #define CLKMSB1         0x5
  32 #define CLKMSB2         0x9
  33 #define CLKMSB3         0xD
  34
  35 /* This is for machines which generate the exact clock. */
  36 #define USECS_PER_JIFFY (1000000/HZ)
  37
  38 #define INTVAL ((10000 / 4) - 1)
  39
  40 static irqreturn_t hp300_tick(int irq, void *dev_id, struct pt_regs *regs)
  41 {
  42         unsigned long tmp;
  43         irqreturn_t (*vector)(int, void *, struct pt_regs *) = dev_id;
  44         in_8(CLOCKBASE + CLKSR);
  45         asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
  46         /* Turn off the network and SCSI leds */
  47         blinken_leds(0, 0xe0);
  48         return vector(irq, NULL, regs);
  49 }
  50
  51 unsigned long hp300_gettimeoffset(void)
  52 {
  53   /* Read current timer 1 value */
  54   unsigned char lsb, msb1, msb2;
  55   unsigned short ticks;
  56
  57   msb1 = in_8(CLOCKBASE + 5);
  58   lsb = in_8(CLOCKBASE + 7);
  59   msb2 = in_8(CLOCKBASE + 5);
  60   if (msb1 != msb2)
  61     /* A carry happened while we were reading.  Read it again */
  62     lsb = in_8(CLOCKBASE + 7);
  63   ticks = INTVAL - ((msb2 << 8) | lsb);
  64   return (USECS_PER_JIFFY * ticks) / INTVAL;
  65 }
  66
  67 void __init hp300_sched_init(irqreturn_t (*vector)(int, void *, struct pt_regs *))
  68 {
  69   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  70   out_8(CLOCKBASE + CLKCR1, 0x1);               /* reset */
  71
  72   asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
  73
  74   cpu_request_irq(6, hp300_tick, IRQ_FLG_STD, "timer tick", vector);
  75
  76   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  77   out_8(CLOCKBASE + CLKCR1, 0x40);              /* enable irq */
  78 }