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/traps.h>
  19 #include <asm/blinken.h>
  20
  21 /* Clock hardware definitions */
  22
  23 #define CLOCKBASE       0xf05f8000
  24
  25 #define CLKCR1          0x1
  26 #define CLKCR2          0x3
  27 #define CLKCR3          CLKCR1
  28 #define CLKSR           CLKCR2
  29 #define CLKMSB1         0x5
  30 #define CLKMSB2         0x9
  31 #define CLKMSB3         0xD
  32
  33 /* This is for machines which generate the exact clock. */
  34 #define USECS_PER_JIFFY (1000000/HZ)
  35
  36 #define INTVAL ((10000 / 4) - 1)
  37
  38 static irqreturn_t hp300_tick(int irq, void *dev_id)
  39 {
  40         unsigned long tmp;
  41         irq_handler_t vector = dev_id;
  42         in_8(CLOCKBASE + CLKSR);
  43         asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
  44         /* Turn off the network and SCSI leds */
  45         blinken_leds(0, 0xe0);
  46         return vector(irq, NULL);
  47 }
  48
  49 unsigned long hp300_gettimeoffset(void)
  50 {
  51   /* Read current timer 1 value */
  52   unsigned char lsb, msb1, msb2;
  53   unsigned short ticks;
  54
  55   msb1 = in_8(CLOCKBASE + 5);
  56   lsb = in_8(CLOCKBASE + 7);
  57   msb2 = in_8(CLOCKBASE + 5);
  58   if (msb1 != msb2)
  59     /* A carry happened while we were reading.  Read it again */
  60     lsb = in_8(CLOCKBASE + 7);
  61   ticks = INTVAL - ((msb2 << 8) | lsb);
  62   return (USECS_PER_JIFFY * ticks) / INTVAL;
  63 }
  64
  65 void __init hp300_sched_init(irq_handler_t vector)
  66 {
  67   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  68   out_8(CLOCKBASE + CLKCR1, 0x1);               /* reset */
  69
  70   asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
  71
  72   if (request_irq(IRQ_AUTO_6, hp300_tick, 0, "timer tick", vector))
  73     pr_err("Couldn't register timer interrupt\n");
  74
  75   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  76   out_8(CLOCKBASE + CLKCR1, 0x40);              /* enable irq */
  77 }