drivers/timer.c

   1 /*
   2  *   OpenBIOS native timer driver
   3  *
   4  *   (C) 2004 Stefan Reinauer <stepan@openbios.org>
   5  *
   6  *   This program is free software; you can redistribute it and/or
   7  *   modify it under the terms of the GNU General Public License
   8  *   version 2
   9  *
  10  */
  11
  12 #include "config.h"
  13 #include "drivers/drivers.h"
  14 #include "timer.h"
  15 #include "asm/io.h"
  16
  17 #if defined(CONFIG_X86) || defined(CONFIG_AMD64)
  18
  19 void setup_timers(void)
  20 {
  21         /* nothing to do */
  22 }
  23
  24 static void load_timer2(unsigned int ticks)
  25 {
  26         /* Set up the timer gate, turn off the speaker */
  27         outb((inb(PPC_PORTB) & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
  28         outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
  29              TIMER_MODE_PORT);
  30         outb(ticks & 0xFF, TIMER2_PORT);
  31         outb(ticks >> 8, TIMER2_PORT);
  32 }
  33
  34 void udelay(unsigned int usecs)
  35 {
  36         load_timer2((usecs * TICKS_PER_MS) / 1000);
  37         while ((inb(PPC_PORTB) & PPCB_T2OUT) == 0);
  38 }
  39
  40 unsigned long currticks(void)
  41 {
  42         static unsigned long totticks = 0UL;    /* High resolution */
  43         unsigned long ticks = 0;
  44         unsigned char portb = inb(PPC_PORTB);
  45
  46         /*
  47          * Read the timer, and hope it hasn't wrapped around
  48          * (call this again within 54ms), then restart it
  49          */
  50         outb(TIMER2_SEL | LATCH_COUNT, TIMER_MODE_PORT);
  51         ticks = inb(TIMER2_PORT);
  52         ticks |= inb(TIMER2_PORT) << 8;
  53         outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
  54              TIMER_MODE_PORT);
  55         outb(0, TIMER2_PORT);
  56         outb(0, TIMER2_PORT);
  57
  58         /*
  59          * Check if the timer was running. If not,
  60          * result is rubbish and need to start it
  61          */
  62         if (portb & PPCB_T2GATE) {
  63                 totticks += (0x10000 - ticks);
  64         } else {
  65                 /* Set up the timer gate, turn off the speaker */
  66                 outb((portb & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
  67         }
  68         return totticks / TICKS_PER_MS;
  69 }
  70 #endif
  71
  72 #ifdef CONFIG_PPC
  73
  74 void setup_timers(void)
  75 {
  76         /* nothing to do */
  77 }
  78
  79 /*
  80  * TODO: pass via lb table
  81  */
  82
  83 unsigned long get_timer_freq(void)
  84 {
  85         return 10000000 / 4;
  86 }
  87
  88 void udelay(unsigned int usecs)
  89 {
  90         unsigned long ticksperusec = get_timer_freq() / 1000000;
  91         _wait_ticks(ticksperusec * usecs);
  92 }
  93
  94 #endif
  95
  96 void ndelay(unsigned int nsecs)
  97 {
  98         udelay((nsecs + 999) / 1000);
  99 }
 100
 101 void mdelay(unsigned int msecs)
 102 {
 103         udelay(msecs * 1000);
 104 }