arch/m68k/hp300/time.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/m68k/hp300/time.c
   4  *
   5  *  Copyright (C) 1998 Philip Blundell <philb@gnu.org>
   6  *
   7  *  This file contains the HP300-specific time handling code.
   8  */
   9
  10 #include <asm/ptrace.h>
  11 #include <linux/types.h>
  12 #include <linux/init.h>
  13 #include <linux/sched.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/interrupt.h>
  16 #include <asm/machdep.h>
  17 #include <asm/irq.h>
  18 #include <asm/io.h>
  19 #include <asm/traps.h>
  20 #include <asm/blinken.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
  39 static irqreturn_t hp300_tick(int irq, void *dev_id)
  40 {
  41         unsigned long tmp;
  42         irq_handler_t vector = dev_id;
  43         in_8(CLOCKBASE + CLKSR);
  44         asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
  45         /* Turn off the network and SCSI leds */
  46         blinken_leds(0, 0xe0);
  47         return vector(irq, NULL);
  48 }
  49
  50 u32 hp300_gettimeoffset(void)
  51 {
  52   /* Read current timer 1 value */
  53   unsigned char lsb, msb1, msb2;
  54   unsigned short ticks;
  55
  56   msb1 = in_8(CLOCKBASE + 5);
  57   lsb = in_8(CLOCKBASE + 7);
  58   msb2 = in_8(CLOCKBASE + 5);
  59   if (msb1 != msb2)
  60     /* A carry happened while we were reading.  Read it again */
  61     lsb = in_8(CLOCKBASE + 7);
  62   ticks = INTVAL - ((msb2 << 8) | lsb);
  63   return ((USECS_PER_JIFFY * ticks) / INTVAL) * 1000;
  64 }
  65
  66 void __init hp300_sched_init(irq_handler_t vector)
  67 {
  68   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  69   out_8(CLOCKBASE + CLKCR1, 0x1);               /* reset */
  70
  71   asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
  72
  73   if (request_irq(IRQ_AUTO_6, hp300_tick, 0, "timer tick", vector))
  74     pr_err("Couldn't register timer interrupt\n");
  75
  76   out_8(CLOCKBASE + CLKCR2, 0x1);               /* select CR1 */
  77   out_8(CLOCKBASE + CLKCR1, 0x40);              /* enable irq */
  78 }